In-shock Cooling in Numerical Simulations

We model a one-dimensional shock-tube using smoothed particle hydrodynamics and investigate the consequences of having finite shock-width in numerical simulations. We investigate the cooling of gas during passage through the shock for different cooling regimes. For a shock temperature of 10^5K, the maximum temperature of the gas is much reduced and the cooling time was reduced by a factor of 2. At lower temperatures, we are especially interested in the production of molecular Hydrogen and so we follow the ionization level and H_2 abundance across the shock. This regime is particularly relevent to simulations of primordial galaxy formation for halos in which the virial temperature of the galaxy is sufficiently high to partially re-ionize the gas. The effect of in-shock cooling is substantial: the maximum temperature the gas reaches compared to the theoretical temperature was found to vary between 0.15 and 0.81 for the simulations performed. The downstream ionization level is reduced from the theoretical level by a factor of between 2.4 and 12.5, and the resulting H_2 abundance was found to be reduced to a fraction of 0.45 to 0.74 of its theoretical value. At temperatures above 10^5K, radiative shocks are unstable and will oscillate. We reproduce these oscillations and find good agreement with the previous work of Chevalier and Imamura (1982), and Imamura, Wolff and Durisen (1984). The effect of in-shock cooling in such shocks is difficult to quantify, but is undoubtedly present.Comment: 8 pages, LaTeX, 7 figure

Hesperioidea e Papilionoidea (Lepidoptera) coligidos em expedição aos Rios Nhamundá e Abacaxis, Amazonas, Brasil: novos subsídios para o conhecimento da biodiversidade da Amazônia Brasileira

Hesperioidea e Papilionoidea (Lepidoptera) coligidos em expedição aos Rios Nhamundá e Abacaxis, Amazonas, Brasil: novos subsídios para o conhecimento da biodiversidade da Amazônia Brasileira. Objetivando um aprimoramento do conhecimento da lepidopterofauna diurna da Amazônia brasileira, este estudo lista 180 taxa coligidos em cinco pontos distintos de dois afluentes do Rio Amazonas, envolvendo as áreas de endemismo Guiana e Rondônia. As coletas foram passivas e ativas e as diferentes localidades comparadas através de análise de Escalonamento Multidimensional Não-Métrico (NMDS).Hesperioidea and Papilionoidea (Lepidoptera) collected in an expedition to the Nhamundá and Abacaxis rivers, Amazonas, Brazil: new insights for understanding the biodiversity of the Brazilian Amazon. Aiming at improving the knowledge of the diurnal lepidopterofauna of the Amazon rainforest, this study lists 180 taxa collected at five different points along two tributaries of the Amazon River, including the Guyana and Rondonia areas of endemism. The different localities were compared using Non-Metric Multidimensional Scaling analysis (NMDS)

How big were the first cosmological objects?

We calculate the cooling times at constant density for halos with virial temperatures from 100 K to 10^5 K that originate from a 3-sigma fluctuation of a CDM power spectrum in three different cosmologies. Our intention is to determine the first objects that can cool to low temperatures, but not to follow their dynamical evolution. We identify two generations of halos: those with low virial temperatures, Tvir < 9000 K that remain largely neutral, and those with larger virial temperatures that become ionized. The lower-temperature, lower-mass halos are the first to cool to 75 percent of their virial temperature. The precise temperature and mass of the first objects are dependent upon the molecular hydrogen (H2) cooling function and the cosmological model. The higher-mass halos collapse later but, in this paradigm, cool much more efficiently once they have done so, first via electronic transitions and then via molecular cooling: in fact, a greater residual ionization once the halos cool below 9000 K results in an enhanced H2 production and hence a higher cooling rate at low temperatures than for the lower-mass halos, so that within our constant-density model it is the former that are the first to cool to really low temperatures. We discuss the possible significance of this result in the context of CDM models in which the shallow slope of the initial fluctuation spectrum on small scales leads to a wide range of halo masses (of differing overdensities) collapsing over a small redshift interval. This ``crosstalk'' is sufficiently important that both high- and low-mass halos collapse during the lifetimes of the massive stars which may be formed at these epochs. Further investigation is thus required to determine which generation of halos plays the dominant role in early structure formation.Comment: 11 pages, 8 figures. Accepted for publication in MNRAS. Inclusion of Helium in the reaction networ

Friction and wear phenomena of vegetable oil based lubricants with additives at severe sliding wear conditions

The tribological responses of palm oil and soybean oil, combined with two commercial antiwear additives (zinc dialkyl dithiophosphate and boron compound), were investigated at a lubricant temperature of 100 °C and under severe contact conditions in a reciprocating sliding contact. The friction coefficient of palm oil with zinc dialkyl dithiophosphate was closest to the commercial mineral engine oil, with a 2% difference. The soybean oil with zinc dialkyl dithiophosphate produced a 57% improvement in wear resistance compared to its pure oil state. The existence of boron nitride in vegetable oils was only responsive in reduction of wear rather than friction. The response of commercial antiwear additives with vegetable oils showed a potential for the future improvement in the performance of vegetable oils

Proceedings of Patient Reported Outcome Measure’s (PROMs) Conference Oxford 2017: Advances in Patient Reported Outcomes Research

A33-Effects of Out-of-Pocket (OOP) Payments and Financial Distress on Quality of Life (QoL) of People with Parkinson’s (PwP) and their Carer

Understanding the relevance of in-mouth food processing. A review of in vitro techniques

[EN] Oral processing of food is the first step in the eating process. Although the food undergoes a number of changes during mastication that influence the subsequent steps, this stage has very often been neglected in studies of digestion, bioavailability, flavor release, satiety potential, glycemic index determination, etc. The present review draws on different sources such as nutrition, medicine, phoniatry and dentistry to explain some in vitro oral processing methods and techniques that could be transferred to food technology studies to mimic in vivo comminution, insalivation, and bolus formation, describing, as a necessary reference, the respective in vivo physiological processes they attempt to imitate. Developing a deeper understanding of all the aspects of in-mouth process will help food technologists to give this crucial step the necessary attention its due importance and to consider better ways to incorporate it into their studies.The authors wish to acknowledge the financial support of the Spanish Government (project AGL2012-36753-C02) and gratefully acknowledge the financial support of EU FEDER funds. Mary Georgina Hardinge assisted with the translation and corrected the English text.Morell Esteve, P.; Hernando Hernando, MI.; Fiszman, SM. (2014). Understanding the relevance of in-mouth food processing. A review of in vitro techniques. Trends in Food Science and Technology. 35(1):18-31. https://doi.org/10.1016/j.tifs.2013.10.005S183135

Nurses' perceptions of aids and obstacles to the provision of optimal end of life care in ICU

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