Computer simulation of fire-sprinkler interaction

The research work presented herein addresses the problem of the mathematical modelling of fire and fire-sprinkler scenarios. This involved the numerical simulation of two-phase, three-dimensional, buoyant, turbulent, recirculating flows. The simulations were carried out in two successive and distinct stages. The first stage dealt with the modelling of buoyant hot turbulent gas flows generated by a fire within room-sized compartments. These single phase studies were based on the field modelling approach to fire simulation. The second part of the study involved the introduction of the cold water droplets through a single sprinkler head, thus, extending the scenario into the more complex two-phase regime. This led to expanding the single-phase fire model to take account of two concurrently present phases, ie. gas/liquid. The strategy used to model the twophase process was the Eulerian-Eulerian technique or volume-fraction method. In order to take into account the physics involved in this process, interphase friction or drag was considered. Furthermore, due to the large difference in temperatures between the hot gases and the cold water droplets it was necessary to introduce interphase heat transfer. Due to the subsequent evaporation of the water droplets interphase mass transfer was also accounted for. Models for both steady-state and time-dependent situations were developed, whereby experimental results of transient fire-sprinkler tests were used for validation. The simulations performed indicated the creation of extremely complex flow fields within the compartments both prior and during sprinkler activation. Phenomena such as the significant cooling of the hot combustion gases caused by the active sprinkler and the evaporation of water droplets have also been predicted. This has been verified by the experimental data. Thus, it can be concluded that the models outlined herein are capable of simulating the complex two-phase fire-sprinkler scenarios. The need for subsequent investigative studies into such areas as the effect of using different auxiliary relationships eg. heat transfer, sprinkler characteristics and gridspacing has been highlighted. In order to complete the validation process, further experimental data needs to be made available. This two-phase technique has proven to be very computationally intensive with simulations requiring days of CPU time. 'Mis is clearly unacceptable. However, it is suggested that parallel computing technology may provide a means for reducing the CPU time involved to hours. It can be concluded that though the model developed requires further investigation and refinements, it provides a basis for a practical and useful fire engineering tool

Megaphone: Latency-conscious state migration for distributed streaming dataflows

We design and implement Megaphone, a data migration mechanism for stateful distributed dataflow engines with latency objectives. When compared to existing migration mechanisms, Megaphone has the following differentiating characteristics: (i) migrations can be subdivided to a configurable granularity to avoid latency spikes, and (ii) migrations can be prepared ahead of time to avoid runtime coordination. Megaphone is implemented as a library on an unmodified timely dataflow implementation, and provides an operator interface compatible with its existing APIs. We evaluate Megaphone on established benchmarks with varying amounts of state and observe that compared to na\"ive approaches Megaphone reduces service latencies during reconfiguration by orders of magnitude without significantly increasing steady-state overhead

Összetett reakciórendszerek egyensúlyi és kinetikai vizsgálata = Equilibrium and kinetic studies of complex chemical systems

A válaszreakciók korábban kidolgozott elméletére alapozva definiáltuk az egyensúlyi csatolás fogalmát. Bemutattuk, hogy - megfelelő körülmények között - szinte törvényszerűen jelentkeznek a Le Chatelier Braun elvnek látszólag ellentmondó jelenségek. Az egyensúlyi csatolás elméletileg megalapozott fogalom, s helyettesitheti a folyamatok egyszerüsitett értelmezéséböl származó, ellentmondásos termodinamikai csatolás fogalmát. Nyolc különböző összetett kinetikai rendszeren végeztünk kinetikai vizsgálatokat, s javasoltunk mechanizmust, amellyekkel számos egzotikus kinetikai jelenség (szuperkatalizis, mintázatképződés, tized-rendű reakció) értelmezhetővé vált. | Based on the theory of response reactions elaborated by us before, we have introduced the concept od equilibrium coupling. It was shown that - under appropriate conditions - the phenomena seemingly in contradiction with the L Catelier Barun principle are almost inevitable in multilple equilibrium systems. The equilibrium coupling is theorethically sound principle and may replace the concept of thermodynamic coupling which is originated from the simplified interpretation of the chemical reactions. Detailed kinetic studies have been carried out in eigth different complex kinetic systems. Based on the experiments appropriate mechanisms are suggested which interpret the different exotic phenomena (super-catalysis, pattern formation, formal reaction order of ten)

Limited Potential or Unfavorable Manipulations? Strategies Toward Efficient Mesenchymal Stem/Stromal Cell Applications

Despite almost 50 years of research and over 20 years of preclinical and clinical studies, the question of curative potential of mesenchymal stem/stromal cells (MSCs) is still widely discussed in the scientific community. Non-reproducible treatment outcomes or even absence of treatment effects in comparison to control groups challenges the potential of these cells for routine application both in tissue engineering and in regenerative medicine. One of the reasons of such outcomes is non-standardized and often disadvantageous ex vivo manipulation of MSCs prior therapy. In most cases, clinically relevant cell numbers for MSC-based therapies can be only obtained by in vitro expansion of isolated cells. In this mini review, we will discuss point by point possible pitfalls in the production of human MSCs for cell therapies, without consideration of material-based applications. Starting with cell source, choice of donor and recipient, as well as isolation methods, we will then discuss existing expansion protocols (two-/three-dimensional cultivation, basal medium, medium supplements, static/dynamic conditions, and hypoxic/normoxic conditions) and influence of these strategies on the cell functionality after implantation. The role of potency assays will also be addressed. The final aim of this mini review is to illustrate the heterogeneity of current strategies for gaining MSCs for clinical applications with their strengths and weaknesses. Only a careful consideration and standardization of all pretreatment processes/methods for the different applications of MSCs will ensure robust and reproducible performance of these cell populations in the different experimental and clinical settings

Effects of environmental enrichment upon ethanol-induced conditioned place preference and pre-frontal BDNF levels in adolescent and adult mice

Environmental enrichment (EE) provides a non-pharmacological tool to alter drug-induced reward, yet its effects on ethanol-induced reward remain controversial. We analyzed adolescent vs. adult (mice) differences in the influence of EE on ethanol-induced conditioned place preference (CPP). The effects of these treatments on brain-derived neurotrophic factor (BDNF) levels in the prefrontal cortex were examined in a separate group of animals. Ethanol-induced CPP was found in adults, and it was similar in EE and in animals reared under standard housing conditions (SC). Adolescents kept under EE, but not those in SC, exhibited CPP. Among SC, but not among EE, adolescents, BDNF levels were significantly lower in those treated with ethanol than in those given vehicle. These results indicate that, compared to adults, adolescent exhibited reduced sensitivity to ethanol's rewarding effects, yet the youth but not the adults exhibited sensitivity to the promoting effect of EE upon CPP by ethanol. Ethanol significantly reduced BDNF levels in adolescents reared under standard housing conditions, but not in adult mice nor in adolescents given EE housing conditions. The present results add to the plethora of adolescent-specific responses to ethanol or to environmental stimuli that may put the youth at risk for escalation of ethanol intake.Fil: Pautassi, Ricardo Marcos. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Investigación Médica Mercedes y Martín Ferreyra. Universidad Nacional de Córdoba. Instituto de Investigación Médica Mercedes y Martín Ferreyra; Argentina. Universidad Nacional de Córdoba. Facultad de Psicología; ArgentinaFil: Suarez, Andrea Beatriz. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Investigaciones Médicas. Universidad de Buenos Aires. Facultad de Medicina. Instituto de Investigaciones Médicas; ArgentinaFil: Hoffmann, Lucas Barbosa. Universidade de Sao Paulo; BrasilFil: Rueda, André Veloso. Universidade de Sao Paulo; BrasilFil: Rae, Mariana. Universidade de Sao Paulo; BrasilFil: Marianno, Priscila. Universidade de Sao Paulo; BrasilFil: Camarini, Rosana. Universidade de Sao Paulo; Brasi

Effect of short-term storage on quality of wheat stored in large polyethylene bags

Abstract: The aim of this study was to compare the short-term storage of food grains in large polyethylene bag silos with the conventional bulk storage of grain regarding quality parameters.  This storage option provides the chance to get along fluctuations in prices without investment in building operations.75 t newly harvested wheat with a dry matter content of 89.1% was stored during a period of six months in two polyethylene bags and as control in a granary on the same farm.  After two weeks, one month, three and six months samples were collected off the first bag below the polyethylene film and in 1.20 m depth and at the same time samples were taken in the granary.  The second bag was kept closed over the six month. Results demonstrated that there are no differences between the measuring points within a bag, between the two bags and no differences between the storage systems regarding the parameters dry matter, pH, starch, crude protein, content of mesophilic microorganisms (bacteria, yeast, mould) and germination.  The temperature in the polyethylene bag silos resembled rapidly to the ambient temperature.  There was no local overheating due to microbiological activity.  The results demonstrate that the temporary grain storage in polyethylene bags does not lead to any grain quality loss compared to the conventional storage.  Because of the very low cost, the flexible bagging system represents an alternative to high investment in permanent storage structures for grain. Key words: wheat, storage, polyethylene bags, quality, costs

Implementierung der Schuss-Schlag-Betäubung im zugelassenen Schlachtbetrieb

A total of 1248 animals was stunned in two EU approved slaughterhouses using either cartridge activated or pneumatic concussion stunning devices. In total, 12 % of the animals had to be stunned twice. If the shooting position deviated from the midline the rate of re-stunning increased considerably. In the main experiment carried out in the larger of the two slaughterhouses 67.8 % of the animals lay without any movement immediately after falling out of the stunning box. Pathological examinations carried out after splitting the skull longitudinally showed a low to high degree of haematoma formation in the brain in more than half of the animals stunned by concussion stunning. The haematomas were localized on the frontal side of the brain immediately beneath the stunning position and on the opposite side of the brain stem. The haematomas occurred also in animals the lamina interna and the dura mater of which were not injured. Following concussion stunning 69 electrocardiograms were made. Except for one animal which could not be evaluated all animals showed normal heart activity corresponding to that observed after captive bolt stunning. The examination of several meat quality parameters did not yield any clear deviations from meat maturation after captive bolt stunning. Meat color, pH value and temperature were measured in the Musculus longissimus dorsi. The most important conclusion of this study is that the application of concussion stunning can improve the safety of the slaughterhouse workers in several critical positions of the slaughtering line (stunning, hoisting and sticking). As long as the dura mater remains intact, the worker responsible for stunning does not come into contact with potentially infected brain material. In addition, after concussion stunning carcass stillness was clearly improved in comparison to captive bolt stunning. However, the results concerning animal welfare are still unsatisfactory as too many animals have to be stunned twice. With respect to consumer protection concussion stunning also does not offer advantages over captive bolt stunning since the distribution of nerval tissue via blood cannot be ruled out because of the haemorrhages occurring in the brain.In zwei industriellen Schlachtbetrieben wurden insgesamt 1248 Tiere entweder mit kartuschen- oder pressluftbetriebenen Schuss-Schlag-Betäubungsapparaten betäubt. Insgesamt mussten 12 % der Tiere nachbetäubt werden. Wich die Ansatzstelle von der Medianen ab, erhöhte sich die Rate der Nachbetäubungen erheblich. Direkt nach dem Auswurf aus der Betäubungsfalle lagen 67,8 % der Tiere im Hauptversuch in dem größeren Schlachtbetrieb völlig ruhig auf dem Trockenlanderost. Bei über der Hälfte der mittels Schuss-Schlag betäubten Tiere fielen bei der pathologisch-anatomischen Untersuchung am längs gespaltenen Schädel gering- bis hochgradige Hämatome am Gehirn auf. Diese waren an der Frontseite direkt unter der Ansatzstelle der Schuss-Schlag-Betäubung und kontralateral am Hirnstamm lokalisiert. Die Hämatome traten auch bei den Tieren auf, bei denen die innere Knochenlamelle und die harte Hirnhaut unverletzt waren. Nach der Schuss-Schlag-Betäubung wurden 69 EKG´s abgeleitet. Die Tiere zeigten bis auf eines, das nicht ausgewertet werden konnte, normale Herzaktionen, wie sie auch nach der Bolzenschussbetäubung bestehen. Bei der Untersuchung einiger Parameter der Fleischqualität fielen keine deutlichen Abweichungen zur Fleischreifung nach einer Bolzenschussbetäubung auf. Gemessen wurde die Farbe, der pH-Wert und die Temperatur des Fleisches am Musculus longissimus dorsi. Als wichtigste Schlussfolgerung bleibt festzuhalten, dass durch Anwendung der Schuss-Schlag-Betäubung beim Rind der Arbeitsschutz an einigen kritischen Arbeitsplätzen (Betäuben, Anschlingen und Stechen) verbessert werden kann. Solange die harte Hirnhaut unversehrt bleibt, kommt der Betäuber nicht mit möglicherweise infiziertem Gehirnmaterial in Kontakt. Auch weisen die Tiere nach der Schuss-Schlag-Betäubung eine bessere Ruhiglage auf dem Rost auf als nach der Bolzenschussbetäubung. Die Ergebnisse bezüglich des Tierschutzes sind dagegen noch unbefriedigend, da zu viele Tiere nachbetäubt werden müssen. Auch für den Verbraucherschutz stellt die Schuss-Schlag-Betäubung im Vergleich zur Bolzenschussbetäubung keine Verbesserung dar, da aufgrund der auftretenden Blutungen am Gehirn eine Verschleppung von Nervengewebe über das Blut nicht ausgeschlossen werden kann

Die kulturelle Seite des Antisemitismus – Zwischen Aufklärung und Shoah

Die Publikation geht auf die internationale Tagung „Die kulturelle Seite des Antisemitismus zwischen Aufklärung und Shoah“ am Ludwig-Uhland-Institut in Tübingen zurück, die im Oktober 2004 in Kooperation mit dem Vidal Sassoon International Center for the Study of Antisemitism an der Hebrew University in Jerusalem (SICSA) veranstaltet wurde. Die deutschen und englischsprachigen Beiträge untersuchen exemplarisch Aspekte der kulturellen Seite des Antisemitismus zwischen dem späten 18. und dem 20. Jahrhundert in Zentraleuropa. Thematisiert werden nicht nur kultur- und geistesgeschichtliche Grundlagen des modernen Antisemitismus, die Tradition und Wirkungsmacht antijüdischer Bilder, Stereotype und Codes, sondern auch alltägliche und diskursive Formen der Judenfeindschaft und Reaktionen von jüdischer Seite auf den Antisemitismus. Als internationaler und interdisziplinärer Forschungsaustausch können die Tübinger kulturwissenschaftlichen Gespräche zu weiteren Diskussionen anregen.Druckfahne der Print-Ausgabe 200