Vorstellung eines neuartigen Brenners zur Erzeugung von turbulenten, verdrallten Kohlenwasserstoff – Diffusionsflammen

Technische industrielle Verbrennung ist meistens turbulente Verbrennung von Kohlenwasserstoffen in Diffusionsflammen. Die Grundlagenforschung auf diesem Gebiet basiert auf den drei Säulen physikalische Modellierung, numerische Simulationen und Validierung durch Experimente meistens mittels Laserdiagnostik. Es gibt eine lange Historie über die Konstruktion und den Bau von geeigneten Brennern, mit denen turbulente Kohlenwasserstoff Diffusionsflammen erzeugt werden können, die sowohl simuliert als auch vermessen werden können. Von diesen beiden Methoden ausgehend gibt es eine Reihe von Restriktionen bezüglich des endgültigen Designs des Brenners und der Flammen, die untersucht werden sollen. Ein kritischer Aspekt sind dabei die lokalen Ruß- und PAH- Konzentrationen in den Flammen, weil alle spektroskopischen Messtechniken, die für Konzentrationsmessungen verwendet werden müssen, durch Ruß und PAH stark gestört werden. Mit den meisten Brennern, die man bis jetzt verwendet hat, hat man versucht, dieses Problem mit mehr oder weniger Erfolg und mit mehr oder weniger Nachteilen bezüglich anderer Aspekte zu überwinden, indem man Kompromisse einging. Wir haben einen neuartigen Brenner entwickelt, der einige dabei auftretenden Probleme löst und den wir als neuen Testfallbrenner vorschlagen. Mit diesem Brenner werden verdrallte turbulente Diffusionsflammen mit sehr wenig lokalen Ruß- und PAH -Konzentrationen geschaffen. Bis jetzt wurde Methan als Brennstoff verwendet. Die Vor- und Nachteile des Brenners und der Flammen werden in diesem Artikel detailliert diskutiert. Weiterhin werden erste Ergebnisse vorgestellt. Mehr Informationen zu diesen Arbeiten sind zu finden unter: http://www. ltt-rostock.de/text/tmd_vbfltt.htm.Technical and industrial combustion is mostly turbulent diffusion combustion with hydrocarbon fuels. Fundamental research on this field is based on three columns, physical modeling, numerical simulations and validation experiments mostly done by laser diagnostics. There is a long tradition in constructing and building burners that will create turbulent hydrocarbon diffusion flames which can be both, simulated and measured. From these both methods result a number of different requirements for the final design of burner and flames to be investigated. One critical aspect is local soot and PAH concentration within the flames due to the fact, that spectroscopic measurement techniques which have to be used for concentration determination are strongly hampered by soot or PAHs. With most of the burners used so far it has been tried to overcome this problem with more or less success and with more or less disadvantages on other aspects as they tried to make a trade-off. We have developed a new kind of burner which will overcome some problems and which we propose as a new test case burner. It creates swirling turbulent diffusion hydrocarbon flames with very low level of local soot or PAHs. So far we used methane as fuel. The advantages and disadvantages of the burner and flames are discussed in detail within this paper. First results are also reported, more information about this work can be found under http://www.ltt-rostock.de/text/tmd_vbfltt.htm.

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The Structure of Goal Contents Across 15 Cultures.

The authors investigated the structure of goal contents in a group of 1,854 undergraduates from 15 cultures around the world. Results suggested that the 11 types of goals the authors assessed were consistently organized in a circumplex fashion across the 15 cultures. The circumplex was well described by positing 2 primary dimensions underlying the goals: intrinsic (e.g., self-acceptance, affiliation) versus extrinsic (e.g., financial success, image) and self-transcendent (e.g., spirituality) versus physical (e.g., hedonism). The circumplex model of goal contents was also quite similar in both wealthier and poorer nations, although there were some slight cross-cultural variations. The relevance of these results for several theories of motivation and personality are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Fluvoxamine in the treatment of binge-eating disorder: a multicenter placebo-controlled, double-blind trial

OBJECTIVE: The purpose of this study was to assess the efficacy of fluvoxamine in the treatment of binge-eating disorder. Binge-eating disorder is a newly described eating disorder characterized by recurrent episodes of binge eating but without purging behaviors. Uncontrolled reports have suggested that serotonin selective reuptake inhibitors (SSRIs) may be effective in treating this disorder. METHOD: Eighty-five outpatients with a DSM-IV diagnosis of binge-eating disorder were randomly assigned to receive either fluvoxamine (N=42) or placebo (N=43) in a 9-week, parallel-group, double-blind, flexible dose (50-300 mg) study at three centers. The primary outcome measures were frequency of binge eating, expressed as log ([binges/week]+1), and Clinical Global Impression (CGI) scale ratings. Secondary measures included the level of response (based on the percentage change in frequency of binges), body mass index, and Hamilton Rating Scale for Depression score. Except for the level of response, the outcome measures were analyzed by random regression methods; the treatment-by-time interaction was the measure of treatment effect. RESULTS: Compared with placebo, fluvoxamine was associated with a significantly greater rate of reduction in the frequency of binges, rate of reduction in CGI severity scores, rate of increase in CGI improvement scores, level of response for patients who completed the 9-week study, and rate of reduction in body mass index. There was no significant difference between placebo and fluvoxamine groups in the rate of decrease in Hamilton depression scale scores. A significantly greater proportion of patients receiving fluvoxamine than those receiving placebo discontinued treatment because of an adverse medical event. CONCLUSIONS: In this placebo-controlled trial, fluvoxamine was found to be effective according to most outcome measures in the acute treatment of binge-eating disorder.     

Acquisition of five high-Mr penicillin-binding protein variants during transfer of high-level beta-lactam resistance from Streptococcus mitis to Streptococcus pneumoniae

Penicillin-resistant isolates of Streptococcus pneumoniae generally contain mosaic genes encoding the low-affinity penicillin-binding proteins (PBPs) PBP2x, PBP2b, and PBP1a. We now present evidence that PBP2a and PBP1b also appear to be low-affinity variants and are encoded by distinct alleles in beta-lactam-resistant transformants of S. pneumoniae obtained with chromosomal donor DNA from a Streptococcus mitis isolate. Different lineages of beta-lactam-resistant pneumococcal transformants were analyzed, and transformants with low-affinity variants of all high-molecular-mass PBPs, PBP2x, -2a, -2b, -1a, and -1b, were isolated. The MICs of benzyl-penicillin, oxacillin, and cefotaxime for these transformants were up to 40, 100, and 50 microg/ml, respectively, close to the MICs for the S. mitis donor strain. Recruitment of low-affinity PBPs was accompanied by a decrease in cross-linked muropeptides as revealed by high-performance liquid chromatography of muramidase-digested cell walls, but no qualitative changes in muropeptide chemistry were detected. The growth rates of all transformants were identical to that of the parental S. pneumoniae strain. The results stress the potential for the acquisition by S. pneumoniae of high-level beta-lactam resistance by interspecies gene transfer.     

DSM-IV intermittent explosive disorder: a report of 27 cases

BACKGROUND: The authors' objective was to provide data regarding the demographic, phenomenological, course of illness, associated psychiatric and medical comorbidity, family history, and psychiatric treatment response characteristics of rigorously diagnosed subjects who met DSM-IV criteria for intermittent explosive disorder. METHOD: Twenty-seven subjects meeting DSM-IV criteria for a current or past history of intermittent explosive disorder were given structured diagnostic interviews. The subjects' medical histories, family histories of psychiatric disorders, and responses to psychiatric treatments were also assessed. RESULTS: Most subjects described their intermittent explosive disorder symptoms as very distressing and/or highly problematic. All 27 subjects described aggressive impulses prior to their aggressive acts. Of 24 subjects who were systematically queried, 21 (88%) experienced tension with the impulses; 18 (75%), relief with the aggressive acts; and 11 (48%), pleasure with the acts. Most subjects stated that their aggressive impulses and acts were also associated with affective symptoms, particularly changes in mood and energy level. Twenty-five (93%) subjects had lifetime DSM-IV diagnoses of mood disorders; 13 (48%), substance use disorders; 13 (48%), anxiety disorders; 6 (22%), eating disorders; and 12 (44%), an impulse-control disorder other than intermittent explosive disorder. Subjects also displayed high rates of comorbid migraine headaches. First-degree relatives displayed high rates of mood, substance use, and impulse-control disorders. Twelve (60%) of 20 subjects receiving monotherapy with an antidepressant or a mood stabilizer reported moderate or marked reduction of their aggressive impulses and/or episodes. CONCLUSION: Intermittent explosive disorder appears to be a bona fide impulse-control disorder that may be related to mood disorder and may represent another form of affective spectrum disorder.     

Strategies towards a better understanding of antibiotic action: folate pathway inhibition in Haemophilus influenzae as an example

Two-dimensional electrophoresis was applied to the global analysis of the cellular response of Haemophilus influenzae to sulfamethoxazole and trimethoprim, both inhibitors of tetrahydrofolate synthesis. Deregulation of the synthesis rate of 118 proteins, involved in different metabolic pathways, was observed. The regulation of the genes involved in the metabolism of the amino acids methionine, threonine, serine, glycine, and aspartate was investigated in detail by analysis of protein synthesis and Northern hybridization. The results suggested that the synthesis of methionine biosynthetic enzymes in H. influenzae is regulated in a similar fashion as in Escherichia coli. A good correlation between the results obtained by Northern hybridization and quantification of protein synthesis was observed. In contrast to trimethoprim, sulfamethoxazole triggered the increased synthesis of the heat shock proteins DnaK, GroEL, and GroES.     

The fabrication of metal matrix composites by a pressureless infiltration technique

A novel technique for fabricating metal matrix composites by the spontaneous (pressureless) infiltration of filler preforms with molten aluminium alloys is described. Numerous reinforcing materials, including Al₂O₃ and SiC of various configurations, such as particles, agglomerates, and fibres, have been incorporated as fillers. The effects of processing variables, such as alloy chemistry, process temperature, and filler material, on the infiltration kinetics and resultant microstructures are discussed. Comparisons with existing infiltration technology and preliminary composite properties are presented.