Modeling and numerical study of primary breakup under diesel conditions

A recently introduced stochastic model for reduced numerical simulation of primary jet breakup is evaluated by comparing model predictions to DNS results for primary jet breakup under diesel conditions. The model uses one-dimensional turbulence (ODT) to simulate liquid and gas time advancement along a lateral line of sight. This one-dimensional domain is interpreted as a Lagrangian object that is advected downstream at the jet bulk velocity, thus producing a flow state expressed as a function of streamwise and lateral location. Multiple realizations are run to gather ensemble statistics that are compared to DNS results. The model incorporates several empirical extensions of the original ODT model that represent the phenomenology governing the Weber number dependence of global jet structure. The model as previously formulated, including the assigned values of tunable parameters, is used here without modification in order to test its capability to predict various statistics of droplets generated by primary breakup. This test is enabled by the availability of DNS results that are suitable for model validation. Properties that are examined are the rate of bulk liquid mass conversion into droplets, the droplet size distribution, and the dependence of droplet velocities on droplet diameter. Quantities of greatest importance for engine modeling are found to be predicted with useful accuracy, thereby demonstrating a more detailed predictive capability by a highly reduced numerical model of primary jet breakup than has previously been achieved

Capability and Technology Performance Goals for the Next Step in Affordable Human Exploration of Space

The capability for living off the land, commonly called in-situ resource utilization, is finally gaining traction in space exploration architectures. Production of oxygen from the Martian atmosphere is called an enabling technology for human return from Mars, and a flight demonstration to be flown on the Mars 2020 robotic lander is in development. However, many of the individual components still require technical improvements, and system-level trades will be required to identify the best combination of technology options. Based largely on work performed for two recent roadmap activities, this paper defines the capability and technology requirements that will need to be achieved before this game-changing capability can reach its full potential

Modeling of Neuronal Growth In Vitro: Comparison of Simulation Tools NETMORPH and CX3D

We simulate the growth of neuronal networks using the two recently published tools, NETMORPH and CX3D. The goals of the work are (1) to examine and compare the simulation tools, (2) to construct a model of growth of neocortical cultures, and (3) to characterize the changes in network connectivity during growth, using standard graph theoretic methods. Parameters for the neocortical culture are chosen after consulting both the experimental and the computational work presented in the literature. The first (three) weeks in culture are known to be a time of development of extensive dendritic and axonal arbors and establishment of synaptic connections between the neurons. We simulate the growth of networks from day 1 to day 21. It is shown that for the properly selected parameters, the simulators can reproduce the experimentally obtained connectivity. The selected graph theoretic methods can capture the structural changes during growth.Peer reviewe

Orientational order parameters of a de Vries–type ferroelectric liquid crystal obtained by polarized Raman spectroscopy and x-ray diffraction

The orientational order parameters 〈P2〉 and 〈P4〉 of the ferroelectric, de Vries–type liquid crystal 9HL have been determined in the SmA* and SmC* phases by means of polarized Raman spectroscopy, and in the SmA* phase using x-ray diffraction. Quantum density functional theory predicts Raman spectra for 9HL that are in good agreement with the observations and indicates that the strong Raman band probed in the experiment corresponds to the uniaxial, coupled vibration of the three phenyl rings along the molecular long axis. The magnitudes of the orientational order parameters obtained in the Raman and x-ray experiments differ dramatically from each other, a discrepancy that is resolved by considering that the two techniques probe the orientational distributions of different molecular axes. We have developed a systematic procedure in which we calculate the angle between these axes and rescale the orientational order parameters obtained from x-ray scattering with results that are then in good agreement with the Raman data. At least in the case of 9HL, the results obtained by both techniques support a “sugar loaf” orientational distribution in the SmA* phase with no qualitative difference to conventional smectics A. The role of individual molecular fragments in promoting de Vries–type behavior is considered

Near-range receiver unit of next generation PollyXT used with Koldeway aerosol Raman lidar in Arctic

The Near-range Aerosol Raman lidar (NARLa) receiver unit, that was designed to enhance the detection range of the NeXT generation PollyXT Aerosol-Depolarization-Raman (ADR) lidar of the University of Warsaw, was employed next the Koldeway Aerosol Raman Lidar (KARL) at the AWI-IPEV German-French station in Arctic during Spring 2015. Here we introduce shortly design of both lidars, the scheme of their installation next to each other, and preliminary results of observations aiming at arctic haze investigation by the lidars and the iCAP a set of particle counter and aethalometer installed under a tethered balloon

Die wirtschaftliche Lage Rußlands: Wachstumsperspektive fehlt weiterhin, Schuldenerlaß keine Lösung. Fünfzehnter Bericht

Der Ausbruch der russischen Finanzkrise im Sommer 1998 brachte für die Wirtschaft des Landes außerordentlich starke Produktionsrückgänge mit sich. Der Rubel verlor etwa drei Viertel seines Wertes, die Reallöhne gingen um etwa ein Drittel zurück. Der Weltmarktpreis für Rohöl hat sich gegenüber seinem Tiefpunkt wieder mehr als verdoppelt. Diese Faktoren trugen dazu bei, daß die russische Wirtschaft, wie einige asiatische Krisenländer auch, die Produktionsrückgänge schneller als zunächst erwartet wieder wettmachen konnte. Die Meinungen über die weiteren Aussichten der russischen Wirtschaft sind nun allerdings sehr geteilt. Die Gruppe der langjährigen Optimisten, die sich von der Krise deutlich geschockt zeigte, knüpft an die zuletzt kräftige Zunahme der Industrieproduktion positive Erwartungen. Die Skeptiker dagegen sehen weiterhin nur eine düstere Zukunft für die russische Wirtschaft. Für beide Positionen lassen sich gewichtige Belege finden. Im folgenden soll auch geprüft werden, ob die jüngsten Entwicklungen geeignet sind, zusätzliches Licht auf die Frage der Zukunftsaussichten für die russische Wirtschaft zu werfen. --

Diet or exercise, or both, for weight reduction in women after childbirth

Background: Weight retention after pregnancy may contribute to obesity. It is known that diet and exercise are recommended components of any weight loss programme in the general population. However, strategies to achieve healthy body weight among postpartum women have not been adequately evaluated. Objectives: The objectives of this review were to evaluate the effect of diet, exercise or both for weight reduction in women after childbirth, and to assess the impact of these interventions on maternal body composition, cardiorespiratory fitness, breastfeeding performance and other child and maternal outcomes. Search methods: We searched the Cochrane Pregnancy and Childbirth Group’s Trials Register (31 January 2012) and LILACS (31 January 2012). We scanned secondary references and contacted experts in the field. We updated the search of the Cochrane Pregnancy and Childbirth Group’s Trials Register on 30 April 2013 and added the results to the awaiting classification section of the review. Selection criteria: All published and unpublished randomised controlled trials (RCTs) and quasi-randomised trials of diet or exercise or both, among women during the postpartum period. Data collection and analysis Both review authors independently assessed trial quality and extracted data. Results are presented using risk ratio (RR) for categorical data and mean difference (MD) for continuous data. Data were analysed with a fixed-effect model. A random-effects model was used in the presence of heterogeneity. Main results: Fourteen trials were included, but only 12 trials involving 910 women contributed data to outcome analysis. Women who exercised did not lose significantly more weight than women in the usual care group (two trials; n = 53; MD -0.10 kg; 95% confidence interval (CI) -1.90 to 1.71). Women who took part in a diet (one trial; n = 45; MD -1.70 kg; 95% CI -2.08 to -1.32), or diet plus exercise programme (seven trials; n = 573; MD -1.93 kg; 95% CI -2.96 to -0.89; random-effects, T² = 1.09, I² = 71%), lost significantly more weight than women in the usual care group. There was no difference in the magnitude of weight loss between diet alone and diet plus exercise group (one trial; n = 43; MD 0.30 kg; 95% CI -0.06 to 0.66). The interventions seemed not to affect breastfeeding performance adversely. Authors’ conclusions: Evidence from this review suggests that both diet and exercise together and diet alone help women to lose weight after childbirth. Nevertheless, it may be preferable to lose weight through a combination of diet and exercise as this improves maternal cardiorespiratory fitness and preserves fat-free mass, while diet alone reduces fat-free mass. This needs confirmation in large trials of high methodological quality. For women who are breastfeeding, more evidence is required to confirm whether diet or exercise, or both, is not detrimental for either mother or baby