A study on the interaction between local flow and flame structure for mixing-controlled Diesel sprays

[EN] A detailed study on the spray local flow and flame structure has been performed by means of PIV and laser-sheet LIF techniques under Diesel spray conditions. Operating conditions were based on Engine Combustion Network recommendations. A consistent comparison of inert and reacting axial velocity fields has produced quantitative information on the effect of heat release on the local flow. Local axial velocity has been shown to increase 50-60% compared to the inert case, while the combustion-induced radial expansion of the spray has been quantified in terms of a 0.9-2.1 mm radius increase. As a result, the drop in entrainment rate has been quantified around 25% compared to the inert case. Streamline analysis also hints at a reduced entrainment under reacting conditions. A 1D spray model under reacting condition has been used, which confirms the modifications obtained in the main flow metrics when moving from inert to reacting conditions. When comparing the flow evolution with the flame structure, little effect of chemical activity on the spray flow upstream the lift-off length has been evidenced, in spite of the presence of formaldehyde in such regions. Only downstream of the lift-off length, as defined by OH LIF, has a strong change in flow pattern been observed as a result of combustion-induced heat release. (C) 2017 The Combustion Institute. Published by Elsevier Inc. All rights reserved.This work was carried out during a scientific visit period by J.M. Garcia-Oliver at IFPEN in 2015, which was funded by the Spanish Ministry of Education, Culture and Sport (Grant PRX14/00192). This study was partially funded by the Spanish Ministry of Economy and Competitiveness in the frame of the COMEFF (TRA2014-59483-R) project.García-Oliver, JM.; Malbec, L.; Toda, HB.; Bruneaux, G. (2017). A study on the interaction between local flow and flame structure for mixing-controlled Diesel sprays. Combustion and Flame. 179:157-171. https://doi.org/10.1016/j.combustflame.2017.01.023S15717117

A conceptual model of the flame stabilization mechanisms for a lifted Diesel-type flame based on direct numerical simulation and experiments

This work presents an analysis of the stabilization of diffusion flames created by the injection of fuel into hot air, as found in Diesel engines. It is based on experimental observations and uses a dedicated Direct Numerical Simulation (DNS) approach to construct a numerical setup, which reproduces the ignition features obtained experimentally. The resulting DNS data are then used to classify and analyze the events that allow the flame to stabilize at a certain Lift-Off Length (LOL) from the fuel injector. Both DNS and experiments reveal that this stabilization is intermittent: flame elements first auto-ignite before being convected downstream until another sudden auto-ignition event occurs closer to the fuel injector. The flame topologies associated to such events are discussed in detail using the DNS results, and a conceptual model summarizing the observation made is proposed. Results show that the main flame stabilization mechanism is auto-ignition. However, multiple reaction zone topologies, such as triple flames, are also observed at the periphery of the fuel jet helping the flame to stabilize by filling high-temperature burnt gases reservoirs localized at the periphery, which trigger auto-ignitions

Deficiency of Src family kinases compromises the repopulating ability of hematopoietic stem cells

OBJECTIVE: Src family kinases (SFK) have been implicated in regulating growth factor and integrin-induced proliferation, migration, and gene expression in multiple cell types. However, little is known about the role of these kinases in the growth, homing, and engraftment potential of hematopoietic stem and progenitor cells. RESULTS: Here we show that loss of hematopoietic-specific SFKs Hck, Fgr, and Lyn results in increased number of Sca-1(+)Lin(-) cells in the bone marrow, which respond differentially to cytokine-induced growth in vitro and manifest a significant defect in the long-term repopulating potential in vivo. Interestingly, a significant increase in expression of adhesion molecules, known to coincide with the homing potential of wild-type bone marrow cells is also observed on the surface of SFK(-/-) cells, although, this increase did not affect the homing potential of more primitive Lin(-)Sca-1(+) SFK(-/-) cells. The stem cell-repopulating defect observed in mice transplanted with SFK(-/-) bone marrow cells is due to the loss of Lyn Src kinase, because deficiency of Lyn, but not Hck or Fgr, recapitulated the long-term stem cell defect observed in mice transplanted with SFK(-/-) bone marrow cells. CONCLUSIONS: Taken together, our results demonstrate an essential role for Lyn kinase in positively regulating the long-term and multilineage engraftment of stem cells, which is distinct from its role in mature B cells and myeloid cells

Inflammatory Cytokine Expression Is Associated with Chikungunya Virus Resolution and Symptom Severity

The Chikungunya virus infection zones have now quickly spread from Africa to parts of Asia, North America and Europe. Originally thought to trigger a disease of only mild symptoms, recently Chikungunya virus caused large-scale fatalities and widespread economic loss that was linked to recent virus genetic mutation and evolution. Due to the paucity of information on Chikungunya immunological progression, we investigated the serum levels of 13 cytokines/chemokines during the acute phase of Chikungunya disease and 6- and 12-month post-infection follow-up from patients of the Italian outbreak. We found that CXCL9/MIG, CCL2/MCP-1, IL-6 and CXCL10/IP-10 were significantly raised in the acute phase compared to follow-up samples. Furthermore, IL-1β, TNF-α, Il-12, IL-10, IFN-γ and IL-5 had low initial acute phase levels that significantly increased at later time points. Analysis of symptom severity showed association with CXCL9/MIG, CXCL10/IP-10 and IgG levels. These data give insight into Chikungunya disease establishment and subsequent convalescence, which is imperative to the treatment and containment of this quickly evolving and frequently re-emerging disease

HIV-1 suppression and durable control by combining single broadly neutralizing antibodies and antiretroviral drugs in humanized mice

Effective control of HIV-1 infection in humans is achieved using combinations of antiretroviral therapy (ART) drugs. In humanized mice (hu-mice), control of viremia can be achieved using either ART or by immunotherapy using combinations of broadly neutralizing antibodies (bNAbs). Here we show that treatment of HIV-1–infected hu-mice with a combination of three highly potent bNAbs not only resulted in complete viremic control but also led to a reduction in cell-associated HIV-1 DNA. Moreover, lowering the initial viral load by coadministration of ART and immunotherapy enabled prolonged viremic control by a single bNAb after ART was withdrawn. Similarly, a single injection of adeno-associated virus directing expression of one bNAb produced durable viremic control after ART was terminated. We conclude that immunotherapy reduces plasma viral load and cell-associated HIV-1 DNA and that decreasing the initial viral load enables single bNAbs to control viremia in hu-mice

Ertüchtigung der Flachschleifmaschine ELB SF 30

Aufbauend auf dem Praktikumsbericht wird in der vorliegenden Bachelorarbeit, das Thema „Ertüchtigung der Flachschleifmaschine ELB“ weiter behandelt. Es wird dabei speziell die Einführung eines neuen Bedienpanels an der Maschine konkretisiert. Zu Beginn erfolgt die Auswahl eines geeigneten Panels, welches zu der vorhandenen Steuerung kompatibel ist. Daraufhin folgt die Vorstellung der Visualisierungssoftware, sowie der Software zum Testen der projektierten Oberfläche des Bediengerätes. Im weiteren Verlauf finden sich Erläuterungen zur Programmierung des Panels, bezogen auf das ELB-Projekt wieder. Das letzte Kapitel bezieht sich auf die konkrete SPS-Lösung zwei ausgewählter Steuerungsfunktionen, zum einen die Magnetsteuerung und zum anderen die Querantriebsteuerung

Corrigendum to:No intolerance of errors "The effect of intolerance of uncertainty on performance monitoring revisited” [Int. J. Psychophysiol. 179 (2022) 77–88, (S0167876022001726), (10.1016/j.ijpsycho.2022.07.001)]

The authors regret to acknowledge three errors in the published article. Primarily, discrepancies were identified in Table 1 (p. 83), specifically pertaining to mean and standard deviation values. Although the accurate values are correctly presented in the variable descriptions in Section 2 (Materials and Methods), they were not appropriately reproduced in the table. Additionally, an oversight was noted in the reporting of the mean and standard deviation of the Inhibitory Intolerance of Uncertainty subscale on page 79. Regrettably, these values were erroneously derived from the Beck Depression Inventory, also listed on the same page. The correct values for Inhibitory IU are M = 11.15, SD = 3.68. Upon a thorough re-examination of all analyses, it was discovered that in Table 3 (p. 84), for the worry model in Model 2, the reported beta of the total IU variable was 0.05, whereas the correct value is 0.06. As a result of this investigation, the two first authors also have carefully checked again all analyses using the publicly available R-script and dataset that accompanied the publication (https://osf.io/4mtn3/) and using the raw data. Via this thorough check, we have verified that all other reported values and statistics in the paper are correct. The three errors above constitute unfortunate mistakes; however, importantly, they do not jeopardize the accuracy of any results and interpretations in the paper. Consequently, the conclusions drawn from this study remain unaffected. The authors would like to apologise for any inconvenience caused.</p

Study of culinary sayings in traditional Lebanese recipes by means of molecular gastronomy

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Characterization of a set of ECN Spray A injectors : nozzle to nozzle variations and effect on spray characteristics

The Engine Combustion Network (ECN) is becoming a leading group concerning the experimental and computational analysis of Engine combustion. In order to establish a coherent database for model validation, all the institutions participating to the experimental effort carry out experiments at well-defined standard conditions (in particular at Spray A conditions: 22.8kg/m3, 900K, 0% and 15% O2) and with Diesel injectors having the same specifications. Due to the rising number of ECN participants and also to unavoidable damages, additional injectors are required. This raises the question of injector's characteristics reproducibility and of the appropriate method to introduce such new injectors in the ECN network. In order to investigate this issue, a set of 8 new injectors with identical nominal Spray A specification were purchased and 4 of them were characterized using ECN standard diagnostics. In particular, the measurements include the nozzle hole diameter, the rate of injection, the liquid and vapor penetrations, the auto-ignition delay and the lift-off length. Variations of ambient temperature, oxygen concentration and density have also been performed. In general the results show similar behavior to ECN standard injectors, confirming that this set of new injectors can be integrated into the pool of ECN injectors. However, discrepancies between spray characteristics were observed, although the injector specifications and the boundary conditions were sensibly the same. The sources of variations from injector to injector are analyzed in order to provide new information on the reproducibility of injectors characteristics, and improve the comparison methodology between experimental data and simulation

Regulation of high-affinity IgE receptor-mediated mast cell activation by murine low-affinity IgG receptors.

Allergic symptoms result from the release of granular and lipidic mediators and of cytokines by inflammatory cells. The whole process is initiated by the aggregation of mast cell and basophil high-affinity IgE receptors (Fc epsilon RI) by IgE and antigen. We report here that IgE-induced release of mediator and cytokine can be inhibited by cross-linking Fc epsilon RI to low-affinity IgG receptors (Fc gamma RII) which are constitutively expressed on mast cells and basophils. Using a model of stable transfectants in RBL-2H3 cells expressing endogeneous rat Fc epsilon RI and recombinant murine Fc gamma RII, we showed that inhibition requires that Fc epsilon RI be crosslinked to Fc gamma RII by the same multivalent ligand. Inhibition of cross-linked receptors left non-cross-linked Fc epsilon RI capable of triggering mediator release and was reversible upon disengagement. Both isoforms of wild-type Fc gamma RII were equally capable of inhibiting Fc epsilon RI-mediated mast cell activation provided they had an intact intracytoplasmic domain. Our results demonstrate that mast cell secretory responses triggered by high-affinity receptors for IgE may be controlled by low-affinity receptors for IgG. This regulation of Fc epsilon RI-mediated mast cell activation is of potential interest in mast cell physiology and in allergic pathology