Ultrasound‐activated Knoevenagel condensation of malononitrile with carbonylic compounds catalysed by alkaline‐doped saponites

α,β‐Unsaturated nitriles have been synthesized by Knoevenagel condensation of a carbonylic compound with malononitrile, assisted by sonochemical irradiation. Two alkaline‐promoted clays (Li⁺‐ and Cs⁺‐exchanged saponites) have been employed as catalysts. The influence of the carbonylic compound (benzaldehyde or cyclohexanone) and the use of a solvent on the catalytic activity have been studied. Remarkable increase in the conversion values has been found when the reaction is activated by ultrasound, as compared with the thermal activation. In this green, solvent‐free procedure, α,β‐unsaturated nitriles have been produced in very high yields (97%) when the Cs⁺‐saponite is used as catalyst. Copyright © 2004 Society of Chemical Industry     

Material state remapping in computational solid mechanics

A computational procedure for remapping material state information from one finite element mesh to another is described. The procedure is useful in connection with evolving meshes for inelastic problems, as for example occur in the context of fracture simulation and adaptive mesh refinement. The proposed method is based on weak enforcement of equality between corresponding fields on the two meshes, where piecewise‐constant fields on both meshes are generalized from the quadrature‐point values. The essential algorithmic problem is that of calculating the volume partition of an arbitrary convex region with respect to a covering set of disjoint convex regions. Instead of geometrically resolving the associated intersections, the problem is herein approximated by a constrained optimization problem, which may be readily and efficiently solved computationally. This formulation is a main contribution of the paper. Computational examples are given that illustrate the effectiveness of the proposed procedure. Copyright © 2002 John Wiley & Sons, Ltd.     

Influence ofAmaranthus hybridus L. allelochemics on oviposition behavior ofSpodoptera exigua andS. eridania (Lepidoptera: Noctuidae)

Common pigweed,Amaranthus hybridus L., is a favorite host of the beet army worm (BAW),Spodoptera exigua L. Chemicals extracted from homogenized pigweed with distilled water, ethanol, or dichloromethane and sprayed back on pigweed deterred oviposition by the BAW. Similarly, water extracts of frass from conspecific larvae or southern armyworm (SAW) larvae,S. eridania (Cramer), fed pigweed leaves and sprayed back on pigweed plants also deterred BAW oviposition, thus confirming that deterrence was due to plant allelochemics rather than specific compounds associated with the metabolic or excretory products of the larvae. Confirmation of the presence of oviposition-deterring chemicals in pigweed was used to explain a previously observed seasonal displacement of BAW by SAW on pigweed in the field.Mention of a commercial or proprietary product does not constitute an endorsement by the USDA.     

A hybrid extended finite element/level set method for modeling phase transformations

A hybrid numerical method for modelling the evolution of sharp phase interfaces on fixed grids is presented. We focus attention on two‐dimensional solidification problems, where the temperature field evolves according to classical heat conduction in two subdomains separated by a moving freezing front. The enrichment strategies of the eXtended Finite Element Method (X‐FEM) are employed to represent the jump in the temperature gradient that governs the velocity of the phase boundary. A new approach with the X‐FEM is suggested for this class of problems whereby the partition of unity is constructed with C¹(Ω) polynomials and enriched with a C⁰(Ω) function. This approach leads to jumps in temperature gradient occurring only at the phase boundary, and is shown to significantly improve estimates for the front velocity. Temporal derivatives of the temperature field in the vicinity of the phase front are obtained with a projection that employs discontinuous enrichment. In conjunction with a finer finite difference grid, the Level Set method is used to represent the evolution of the phase interface. An iterative procedure is adopted to satisfy the constraints on the temperature field on the phase boundary. The robustness and utility of the method is demonstrated with several benchmark problems of phase transformation. Copyright © 2002 John Wiley & Sons, Ltd.     

A Composite Index of Compliance for Chronic In‐Center Hemodialysis Patients

We developed a composite compliance index as the sum of the compliance scores for interdialytic weight gain (IDWG), pre‐dialysis serum potassium and phosphorus concentrations (each scored from zero to 3, with 3 indicating the poorest compliance), and skipping hemodialysis sessions (scored from zero to 9, with 9 indicating the poorest compliance). We used this composite score to prospectively evaluate compliance in 25 prevalent hemodialysis patients over a period of 1 year. We then followed these patients for another 3.5 years. The patients studied were divided into two groups: group A (poor compliance) consisted of 9 subjects with composite score ≥ 9 (13.2 ± 3.2); group B (better compliance) consisted of 16 subjects with composite score < 9 (4.7 ± 1.8). Age, duration of hemodialysis, and frequency of diabetes mellitus did not differ between the groups. Group A contained higher fractions of subjects with history of alcoholism (66.7% vs 12.5%, p = 0.010), other substance addiction (44.4% vs 0%, p = 0.010), and severe psychosocial problems (88.9% vs 18.8%, p = 0.002). Mean survival from the beginning of observation, estimated by actuarial life‐table survival analysis, was 1.19 years in group A and 2.60 years in group B (p = 0.0265). A composite compliance index incorporating domains indicating adherence to diet, medications, and dialysis schedule identified other behavioral problems in poorly compliant patients. Hemodialysis patients characterized by this composite index as poorly compliant had shortened survival.     

Temperature effects on the mass flow rate in the SBI and similar heat‐release rate test equipment

In various medium‐to‐large‐scale fire test equipments like the ISO room corner test (RC), and more recently, the single burning item test (SBI) the mass flow rate measurement of the combustion gases plays a key role in the determination of the heat‐release rate and smoke‐production rate. With the knowledge of the velocity profile and the temperature of the flow, the mass flow rate is obtained by measuring the velocity on the axis of the duct. This is done by means of a bi‐directional probe based on the pitot principle. However, due to the variation of the mean temperature and the temperature gradient in any cross section of the duct, introduced by ever changing combustion gas temperatures, the velocity nor the density profile are constant in time. This paper examines the resulting uncertainty on the mass flow rate. Copyright © 2006 John Wiley & Sons, Ltd.     

Automatic playlist generation based on tracking user’s listening habits

Algorithms for automatic playlist generation solve the problem of tedious and time consuming manual selection of musical playlists. These algorithms generate playlists according to the user’s music preferences of the moment. The user describes his preferences either by manually inputting a couple of example songs, or by defining constraints for the choice of music. The approaches to automatic playlist generation up to now were based on examining the metadata attached to the music pieces. Some of them took also the listening history into account. But anyway, a heavy accent has been put on the metadata, while the listening history, if it was used at all, had a minor role. Missings and errors in metadata frequently appear, especially when the music is acquired from the Internet. When the metadata is missing or wrong, the approaches proposed so far cannot work. Besides, entering constraints for the playlist generation can be a difficult activity. In our approach we ignored the metadata and focused on examining the listening habits. We developed two simple algorithms that track the listening habits and form a listener model—a profile of listening habits. The listener model is then used for automatic playlist generation. We developed a simple media player which tracks the listening habits and generates playlists according to the listener model. We tried the solution with a group of users. The experiment was not a successful one, but it threw some new light on the relationship between the listening habits and playlist generation.     

Improvement of levitation characteristics in a magnetic bearing system using HTSC‐permanent magnet hybrid structure

Magnetic bearing using pinning force of a permanent magnet and a high‐temperature superconductor has been developed. Additional permanent magnet is introduced to increase the levitation force of the magnetic bearing. In this hybrid magnetic bearing system, levitation force is mainly given by the repulsive force of the permanent magnets, and stability for the lateral direction is given by pinning force of the superconductor. The experimental device is developed. A ring‐type superconductor and a bulk one are examined. Levitation characteristics of the hybrid magnetic bearing are measured. The bulk superconductor shows better characteristics of both levitation and lateral stability than the ring one. Levitation force of the hybrid system becomes about twice as large as that of the nonhybrid one. Although, the repulsive force of the permanent magnet decreases the lateral stability of the system, its influence becomes small by choosing an adequate position of the permanent magnets and the superconductor. © 2004 Wiley Periodicals, Inc. Electr Eng Jpn, 150(1): 71–77, 2005; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/eej.10350     

Performance prediction of a hybrid‐excitation synchronous machine with axially arranged excitation poles and permanent‐magnet poles

This paper presents a method of predicting the steady‐state performance of a new hybrid‐excitation synchronous machine (HESM) theoretically. The field pole of this HESM is axially divided into two parts; one is an excitation part and the other a permanent‐magnet (PM) part. A nonlinear equivalent circuit, which can include the saliency of the rotor and the magnetic saturation due to the iron core, is derived. Based on this equivalent circuit, the steady‐state performance of the HESM is calculated, and the results are confirmed through experiments. © 2004 Wiley Periodicals, Inc. Electr Eng Jpn, 150(2): 43–49, 2005; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/eej.20033