781 research outputs found
Towards integrated powertrain control: thermal management of NG heated catalyst system
Towards Integrated Powertrain Control: Thermal Management of NG Heated Catalyst System — The conversion efficiency of catalytic converters is mainly defined by the temperature range wherein they are operating. Traditionally, ignition retard has been used to reduce the light-off time of the catalyst. This is however associated with a fuel penalty. With increasing vehicle electrification, external heating facilities present an alternative, especially for hybrid vehicles. Nevertheless, system complexity of hybrid vehicles prevents engineers to evaluate possible heating technologies with respect to traditional solutions
Freeze–thaw cycles have minimal effect on the mineralisation of low molecular weight, dissolved organic carbon in Arctic soils
Warmer winters in Arctic regions may melt
insulating snow cover and subject soils to more freeze–
thaw cycles. The effect of freeze–thaw cycles on the
microbial use of low molecular weight, dissolved organic
carbon (LMW-DOC) is poorly understood. In this study,
soils from the Arctic heath tundra, Arctic meadow tundra
and a temperate grassland were frozen to -7.5 C and
thawed once and three times. Subsequently, the mineralisation of 3 LMW-DOC substrates types (sugars, amino
acids and peptides) was measured over an 8-day period and
compared to controls which had not been frozen. This
allowed the comparison of freeze–thaw effects between
Arctic and temperate soil and between different substrates.
The results showed that freeze–thaw cycles had no significant effect on C mineralisation in the Arctic tundra
soils. In contrast, for the same intensity freeze–thaw cycles,
a significant effect on C mineralisation was observed for all
substrate types in the temperate soil although the response
was substrate specific. Peptide and amino acid mineralisation were similarly affected by FT, whilst glucose had a
different response. Further work is required to fully
understand microbial use of LMW-DOC after freeze–thaw,
yet these results suggest that relatively short freeze–thaw
cycles have little effect on microbial use of LMW-DOC in
Arctic tundra soils after thaw
Entrainment of the Melatonin Rhythms in Early Postnatal Lambs and Their Mothers
Although the developing sheep can produce an appropriately timed melatonin rhythm as early as 1 week after birth, it is not known whether the lamb is able to adjust its melatonin rhythm to a change in daylength. The ability of the young lamb to entrain its pattern of melatonin secretion to a new photoperiod was determined in the present study. Eight female lambs and their mothers were raised in long days (LD 16:8) beginning 2 weeks post partum. At 7 weeks of age, the time of lights-off was advanced 8 hr, the short-day photoperiod then being LD 8:16; the time of lights-on remained unchanged. Concentrations of melatonin were measured in blood samples collected hourly on days - 1, 0, 2, 4, 6, and 13 relative to the light change. On day 0, all mothers and daughters had advanced the onset of melatonin secretion by at least 1 hr, and by day 13, 12 of 16 had completely entrained to the new photoperiod. The rate of entrainment among individuals varied; the mean rate for lambs and mothers did not differ. This study provides evidence that the melatonin-rhythm-generating system matures shortly after birth.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/68290/2/10.1177_074873048900400405.pd
Experimental Facilities Development
This research was sponsored by the National Science Foundation Grant NSF PHY 87-1440
Study of the Giant Resonance Region by Inelastic Scattering of Polarized Protons
Supported by the National Science Foundation and Indiana Universit
Search for 3p-3h States in the A=12 and 16 Systems with the (6-Li,t) and (6-Li,3-He) Reaction
Supported by the National Science Foundation and Indiana Universit
Excitation of the Giant Resonance Region by Inelastic Scattering of Polarized Protons
This work was supported by the National Science Foundation Grants NSF PHY 78-22774 A03, NSF PHY 81-14339, and by Indiana Universit
Measurements of the (n,p) Reaction at IUCF
This research was sponsored by the National Science Foundation Grant NSF PHY 87-1440
Analyzing Powers for Deuteron-Induced Reactions Leading to Continuum Final States
This work was supported by the National Science Foundation Grant NSF PHY 78-22774 A02 & A03 and by Indiana Universit
Study of (n,p) Reactions Between 100 and 200 MeV
This research was sponsored by the National Science Foundation Grant NSF PHY 87-1440
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