Investigations of Protostellar Outflow Launching and Gas Entrainment: Hydrodynamic Simulations and Molecular Emission

We investigate protostellar outflow evolution, gas entrainment, and star formation efficiency using radiation-hydrodynamic simulations of isolated, turbulent low-mass cores. We adopt an X-wind launching model, in which the outflow rate is coupled to the instantaneous protostellar accretion rate and evolution. We vary the outflow collimation angle from $\theta$=0.01-0.1 and find that even well collimated outflows effectively sweep up and entrain significant core mass. The Stage 0 lifetime ranges from 0.14-0.19 Myr, which is similar to the observed Class 0 lifetime. The star formation efficiency of the cores spans 0.41-0.51. In all cases, the outflows drive strong turbulence in the surrounding material. Although the initial core turbulence is purely solenoidal by construction, the simulations converge to approximate equipartition between solenoidal and compressive motions due to a combination of outflow driving and collapse. When compared to a simulation of a cluster of protostars, which is not gravitationally centrally condensed, we find that the outflows drive motions that are mainly solenoidal. The final turbulent velocity dispersion is about twice the initial value of the cores, indicating that an individual outflow is easily able to replenish turbulent motions on sub-parsec scales. We post-process the simulations to produce synthetic molecular line emission maps of $^{12}$CO, $^{13}$CO, and C$^{18}$O and evaluate how well these tracers reproduce the underlying mass and velocity structure.Comment: Accepted to ApJ, 17 pages, 15 figure

Coupled Elastodynamics of Piston Compression Ring Subject to Sweep Excitation

The piston compression ring's primary function is to seal the combustion chamber, thus mitigating gas leakage to the crankcase and avoiding loss of pressure loading. As a result, the ring is meant to conform closely to the cylinder surface which promotes increased friction. The compression ring is subjected to combustion pressure loading, ring tension, varying inertial force and friction. It is a slender ring of low mass, thus undergoes complex elastodynamic behaviour, when subjected to a multitude of forces. These motions occur in the ring's radial in-plane and axial out-of-plane dynamics, which comprise flutter, ring axial jump, compression-extension, ring twist and rotational drag. An implication of these motions can be loss of sealing, gas blow-by, loss of power and lubricant degradation/oil loss, to name but a few. Consequently, understanding and accurately predicting ring dynamic behaviour under transient conditions is an important step in any subsequent modelling for evaluation of cylinder system efficiency. There have been a plethora of investigations for ring dynamics, often decoupling the ring behaviour in its in-plane and out-of-plane motions. This approach disregards any transfer of dynamic energy from one degree of freedom to another which is only applicable to rectangular ring cross-sections. Alternatively, there are computationally intensive approaches such as finite element analysis which are not conducive for inclusion in any subsequent system level engine modelling where ring response alters in an instantaneous manner. This would require embedded finite element analysis within a transient analysis. This paper presents a finite difference numerical analysis for coupled in-plane and out-of-plane motions of compression rings with practical cross-sectional geometries, which are mostly not rectangular. The formulated method can be integrated into a system level transient cyclic analysis of ring-bore contact. The presented approach takes into account the energy transfer between different degrees of freedom. The predictions are validated against precise non-contact measurements of ring elastodynamic behaviour under amplitude-frequency sweeps. This approach has not hitherto been reported in literature and constitutes the main contribution of the paper

An Investigation into the Oil Transport and Starvation of Piston-Ring Pack

In order to accurately predict the lubricant film thickness and generated friction in any tribological contact, it is important to determine appropriate boundary conditions, taking into account the oil availability and extent of starvation. This paper presents a two-dimensional hydrodynamic model of a piston ring pack for prediction of lubricant film thickness, friction and total power loss. The model takes into account starvation caused by reverse flow at the conjunctional inlet wedge, and applied to a ring pack, comprising a compression and scraper ring. Inlet boundaries are calculated for an engine cycle of a four-cylinder, four-stroke gasoline engine operating at 1500 r/min with conditions pertaining to the New European Drive Cycle. The analysis shows the two main sources of starvation: first, due to a physical lack of inlet meniscus and second, due to reverse flow at the inlet wedge significantly affecting the prevailing conditions from the generally assumed idealised boundary conditions. Such an approach has not hitherto been reported in literature

RTL551 Treatment of EAE Reduces CD226 and T-bet+ CD4 T Cells in Periphery and Prevents Infiltration of T-bet+ IL-17, IFN-γ Producing T Cells into CNS

Recombinant T cell receptor ligands (RTLs) that target encephalitogenic T-cells can reverse clinical and histological signs of EAE, and are currently in clinical trials for treatment of multiple sclerosis. To evaluate possible regulatory mechanisms, we tested effects of RTL therapy on expression of pathogenic and effector T-cell maturation markers, CD226, T-bet and CD44, by CD4+ Th1 cells early after treatment of MOG-35-55 peptide-induced EAE in C57BL/6 mice. We showed that 1–5 daily injections of RTL551 (two-domain I-Ab covalently linked to MOG-35-55 peptide), but not the control RTL550 (“empty” two-domain I-Ab without a bound peptide) or Vehicle, reduced clinical signs of EAE, prevented trafficking of cells outside the spleen, significantly reduced the frequency of CD226 and T-bet expressing CD4+ T-cells in blood and inhibited expansion of CD44 expressing CD4+ T-cells in blood and spleen. Concomitantly, RTL551 selectively reduced CNS inflammatory lesions, absolute numbers of CNS infiltrating T-bet expressing CD4+ T-cells and IL-17 and IFN-γ secretion by CNS derived MOG-35-55 reactive cells cultured ex vivo. These novel results demonstrate that a major effect of RTL therapy is to attenuate Th1 specific changes in CD4+ T-cells during EAE and prevent expansion of effector T-cells that mediate clinical signs and CNS inflammation in EAE

Effect of cylinder de-activation on the tribological performance of compression ring conjunction

The paper presents transient thermal-mixed-hydrodynamics of piston compression ring-cylinder liner conjunction for a 4-cylinder 4-stroke gasoline engine during a part of the New European Drive Cycle (NEDC). Analyses are carried out with and without cylinder de-activation (CDA) technology in order to investigate its effect upon the generated tribological conditions. In particular, the effect of CDA upon frictional power loss is studied. The predictions show that overall power losses in the piston-ring cylinder system worsen by as much as 10% because of the increased combustion pressures and liner temperatures in the active cylinders of an engine operating under CDA. This finding shows the down-side of this progressively employed technology, which otherwise is effective in terms of combustion efficiency with additional benefits for operation of catalytic converters. The expounded approach has not hitherto been reported in literature

Targeted natural killer cell–based adoptive immunotherapy for the treatment of patients with NSCLC after radiochemotherapy: a randomized phase II clinical trial

Purpose: Non–small cell lung cancer (NSCLC) is a fatal disease with poor prognosis. A membrane-bound form of Hsp70 (mHsp70) which is selectively expressed on high-risk tumors serves as a target for mHsp70-targeting natural killer (NK) cells. Patients with advanced mHsp70-positive NSCLC may therefore benefit from a therapeutic intervention involving mHsp70-targeting NK cells. The randomized phase II clinical trial (EudraCT2008-002130-30) explores tolerability and efficacy of ex vivo–activated NK cells in patients with NSCLC after radiochemotherapy (RCT). Patients and Methods: Patients with unresectable, mHsp70-positive NSCLC (stage IIIa/b) received 4 cycles of autologous NK cells activated ex vivo with TKD/IL2 [interventional arm (INT)] after RCT (60–70 Gy, platinum-based chemotherapy) or RCT alone [control arm (CTRL)]. The primary objective was progression-free survival (PFS), and secondary objectives were the assessment of quality of life (QoL, QLQ-LC13), toxicity, and immunobiological responses. Results: The NK-cell therapy after RCT was well tolerated, and no differences in QoL parameters between the two study arms were detected. Estimated 1-year probabilities for PFS were 67% [95% confidence interval (CI), 19%–90%] for the INT arm and 33% (95% CI, 5%–68%) for the CTRL arm (P = 0.36, 1-sided log-rank test). Clinical responses in the INT group were associated with an increase in the prevalence of activated NK cells in their peripheral blood

Detour and break optimising distance, a new perspective on transport and urbanism

International audienceFrom a discussion about the mathematical properties of metrics, we identify three fundamental characteristics of distance, which are optimality, detour and break. We then explore the implications of these properties for transport planning, urbanism and spatial planning. We state that distances contain the idea of optimum and that any distance is associated to a search for optimisation. Pedestrian movements obey this principle and sometimes depart from designed routes. Local sub-optimality conveyed by public transport maps has to be corrected by interventions on public space to relieve the load on central parts of networks. The second principle we state is that detour in distances is most often a means to optimise movement. Fast transport systems generates most of the detour observed in geographical spaces at regional scale. This is why detour has to be taken into account in regional transport policies. The third statement is that breaks in movement contribute to optimising distances. Benches, cafés, pieces of art, railway stations are examples of the urban break. These facilities of break represent an urban paradox: they organise the possibility of a break, of a waste of time in a trip, and they also contribute to optimising distances in a wider network. In that sense break should be considered as a relevant principle for the design of urban space in order to support a pedestrian oriented urban form

Boundary friction characterisation of a used cylinder liner subject to fired engine conditions and surface deposition

In cylinder friction contributes as a primary source of parasitic dissipations in IC engines. For future engines to become more efficient, with enhanced fuel economy and increased power output, accurate prediction of new designs is required over the full lifetime of an engine. The work carried out presents use of a local pressure coefficient of boundary shear strength of asperities value, taking into account the localised effects of surface texture, coating and surface deposition. XPS spectra analysis was also carried out to identify the surface depositions as a result of combustion, not previously taken into account during piston ring pack simulation. Friction was shown by simulation to drop by up to 30% between the compression and combustion stroke as a result of using a carriable coefficient of boundary shear strength of asperities. It was found that piston varnish on the liner corresponded to higher values of the pressure coefficient of boundary shear strength of asperities, therefore showing the importance of using real system components run under representative operating conditions or numerical analyses

Probing Episodic Accretion in Very Low Luminosity Objects

Episodic accretion has been proposed as a solution to the long-standing luminosity problem in star formation; however, the process remains poorly understood. We present observations of line emission from N2H+ and CO isotopologues using the Atacama Large Millimeter/submillimeter Array (ALMA) in the envelopes of eight very low luminosity objects (VeLLOs). In five of the sources the spatial distribution of emission from N2H+ and CO isotopologues shows a clear anticorrelation. It is proposed that this is tracing the CO snow line in the envelopes: N2H+ emission is depleted toward the center of these sources, in contrast to the CO isotopologue emission, which exhibits a peak. The positions of the CO snow lines traced by the N2H+ emission are located at much larger radii than those calculated using the current luminosities of the central sources. This implies that these five sources have experienced a recent accretion burst because the CO snow line would have been pushed outward during the burst because of the increased luminosity of the central star. The N2H+ and CO isotopologue emission from DCE161, one of the other three sources, is most likely tracing a transition disk at a later evolutionary stage. Excluding DCE161, five out of seven sources (i.e., ~70%) show signatures of a recent accretion burst. This fraction is larger than that of the Class 0/I sources studied by Jørgensen et al. and Frimann et al., suggesting that the interval between accretion episodes in VeLLOs is shorter than that in Class 0/I sources