An evaluation of detailed reaction mechanisms for hydrogen combustion under gas turbine conditions

Chemical kinetics in hydrogen combustion for elevated pressures have recently become more relevant because of the implementation of hydrogen as a fuel in future gas turbine combustion applications, such as IGCC or IRCC systems. The aim of this study is to identify a reaction mechanism that accurately represents H₂/O₂ kinetics over a large range of conditions, particularly at elevated pressures as present in a gas turbine combustor. Based on a literature review, six mechanisms of different research groups have been selected for further comparisons within this study. Reactor calculations of ignition delay times show that the mechanisms of Li et al. and Ó Conaire et al. yield the best agreement with data from shock tube experiments at pressures up to 33 bar. The investigation of one-dimensional laminar hydrogen flames indicate that these two mechanisms also yield the best agreement with experimental data of laminar flame speed, particularly for elevated pressures. The present study suggests that the Li mechanism is best suited for the prediction of H₂/O₂ chemistry since it includes more up-to date data for the range of interest.     

A database approach for information communication in a peer‐to‐peer collaborative CAD environment

Timely and efficient information communication is a key factor in ensuring successful collaboration in engineering collaborative design. This work proposes a database approach to support information communication between distributed and autonomous CAD systems. It provides the designer with an easy and flexible way, a project‐based propagation meta‐table, to specify what parts of a CAD information model should be communicated to other collaborating designers. A CAD peer manager, containing a peer database that stores information to be exchanged with the other collaborators, wraps each participating CAD system. The peer manager identifies changes made to the CAD model by using stored procedures and active rules in the peer database that are automatically generated based on the propagation meta‐table. The identified updates are propagated in a timely manner to other peers via inter‐database message passing, thereby minimizing the volume of necessary information to be exchanged. Furthermore, remote peer designers can flexibly incorporate, filter, or delete received updates by using a propagation control interface, which is also used to issue user's commands to download the data from the CAD system to the peer database and lookup the received messages in the peer database. The approach is applicable on any CAD system having a CORBA interface and can also be applied to other kinds of object‐oriented interfaces. Copyright © 2007 John Wiley & Sons, Ltd.     

Exploring the active-site of a rationally redesigned lipase for catalysis of Michael-type additions

Michael-type additions of various thiols and alpha,beta-unsaturated carbonyl compounds were performed in organic solvent catalyzed by wild-type and a rationally redesigned mutant of Candida antarctica lipase B. The mutant lacks the nucleophilic serine 105 in the active-site; this results in a changed catalytic mechanism of the enzyme. The possibility of utilizing this mutant for Michael-type additions was initially explored by quantum-chemical calculations on the reaction between acrolein and methanethiol in a model system. The model system was constructed on the basis of docking and molecular-dynamics simulations and was designed to simulate the catalytic properties of the active site. The catalytic system was explored experimentally with a range of different substrates. The kca values were found to be in the range of 10(-3) to 4 min(-1), similar to the values obtained with aldolase antibodies. The enzyme proficiency was 10(7). Furthermore, the Michael-type reactions followed saturation kinetics and were confirmed to take place in the enzyme active site.     

The Wavelength Dependence of Scattered Light Intensity in Rabbit Corneas

It is well known that the almost lossless transmission of light through normal mammalian corneas, an obvious fact, requires a theoretical explanation. The reason for this is the pronounced scattering one would expect if the spatial arrangement of the large number of long transversely submicroscopic fibrils that exist in the stroma were purely random. In a recent theory it was shown that the high corneal transparency can be quantitatively well explained if the fibril arrangement can be described in terms of distorted lattices. One conclusion of this theory is that the ratio of scattered light intensity to incident light intensity in the stroma should be inversely proportional to the fifth power of the light wavelength. In the present work this ratio has been measured for 12 rabbit corneas as a function of the wavelength in the range 3900 to 7250 ?. The results are in very good agreement with the theoretical prediction.     

Application of the finite element method to machinery

The finite element method has given the designer of machinery components and structures a new tool for analysis of stresses, temperatures and dynamic vibrations.In the following some applications of the tool to different problems within this field are shown (by some examples), using the SESAM-69 complex.Three-dimensional solids as well as three-dimensional plate and bar structures are treated, and the results are compared to analytical or experimental solutions where such are known.These examples should verify the FEM as very attractive to the modem machinery-designer.     

Gert Wingårdh

From his main office in Gothenburg, Sweden's second city, Gert Wingårdh has spawned a practice that has brought him national success. He has completed two embassy buildings for the Swedish foreign office in Washington DC and Berlin and two major museums. Timothy Tore Hebb describes the work of an architect whose designs are able to be both responsive to the natural environment and ingenious in their juxtapositions and contrasts. Copyright © 2007 John Wiley & Sons, Ltd.     

Group climate development in cognitive and interpersonal group therapy for social phobia.

This study was designed as a longitudinal study of 80 participants in cognitive group therapy (RCT, n = 40) and interpersonal group therapy (RIPT, n = 40) for social phobia during 10 weeks of residential therapy. The aim was to investigate the patterns of group climate development and its impact on treatment outcome. Data were collected using MacKenzie's Group Climate Questionnaire (GCQ) 4 times during treatment, and a multilevel (mixed) model approach was used in the analyses. Engagement in RCT groups showed a linear increase during treatment in contrast to a linear decline among patients in RIPT groups. This divergence might be explained by the focus on extragroup and intragroup relationships in RCT and RIPT, respectively. Neither conflict nor avoidance followed the expected pattern, nor did their mean levels influence outcome. However, when 6 extreme values of conflict were removed, there was support for a low–high–low pattern of conflict. In general, these results do not support MacKenzie's generic model of group climate development but suggest that sample characteristics, treatment models, and setting can play major roles in determining the group climate. Of the group climate variables, only the mean level of engagement predicted a change in social anxiety over the course of treatment. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

Synthesis of N-Aryl- and N-alkyl-Substituted Imidazolium Silver Complexes: Cytotoxic Screening by Using Human Cell Lines Modelling Acute Myeloid Leukaemia

A series of N-aryl- and N-alkyl substituted imidazoles has been synthesised and complexed with Ag⁺ to obtain silver-NHC complexes of the form [Ag(NHC)₂]X. These silver-NHC complexes were tested in vitro against the human cell lines HL-60 and MOLM-13, which both model acute myeloid leukaemia (AML). A substantial difference in cytotoxicity was revealed varying in the range 13–4 μM and 22–9 μM for HL-60 and MOLM-13, respectively. Furthermore, this study revealed that when an alkyl group is installed on the imidazole scaffold, its position substantially influences the cytotoxicity of the corresponding silver NHC complex.     

The relationship between activating affects, inhibitory affects, and self-compassion in patients with Cluster C personality disorders.

In the short-term dynamic psychotherapy model termed “Affect Phobia Treatment,” it is assumed that increase in patients' defense recognition, decrease in inhibitory affects (e.g., anxiety, shame, guilt), and increase in the experience of activating affects (e.g., sadness, anger, closeness) are related to enhanced self-compassion across therapeutic approaches. The present study aimed to test this assumption on the basis of data from a randomized controlled trial, which compared a 40-session short-term dynamic psychotherapy (N = 25) with 40-session cognitive treatment (N = 25) for outpatients with Cluster C personality disorders. Patients' defense recognition, inhibitory affects, activating affects, and self-compassion were rated with the Achievement of Therapeutic Objectives Scale (McCullough et al., 2003b) in Sessions 6 and 36. Results showed that increase in self-compassion from early to late in therapy significantly predicted pre- to post-decrease in psychiatric symptoms, interpersonal problems, and personality pathology. Decrease in levels of inhibitory affects and increase in levels of activating affects during therapy were significantly associated with higher self-compassion toward the end of treatment. Increased levels of defense recognition did not predict higher self-compassion when changes in inhibitory and activating affects were statistically controlled for. There were no significant interaction effects with type of treatment. These findings support self-compassion as an important goal of psychotherapy and indicate that increase in the experience of activating affects and decrease in inhibitory affects seem to be worthwhile therapeutic targets when working to enhance self-compassion in patients with Cluster C personality disorders. (PsycINFO Database Record (c) 2011 APA, all rights reserved)