This study examined the foraging locations of adult male and female Antarctic fur seals (Arctocephalus gazella) in the Scotia Sea during the postbreeding period. Satellite transmitters were used to track adult males and females and to obtain information about dive depths. Male fur seals migrated away from the breeding area during the postbreeding period whereas females remained close to the breeding grounds and foraged in the same area during two consecutive years. The most intensive foraging by females was associated with the edge of the continental shelf of South Georgia. Males dived deeper than females. Counts of males at South Georgia and at the South Orkney Islands support the result from satellite tracking data showing that males move from South Georgia to the South Orkney Islands at the end of the breeding season. Unlike males, females were limited in their foraging range by the necessity to return to feed dependent young, so breeding sites are likely to be located close to foraging areas that are optimal for females. Locations used for feeding by females were avoided by males, either because they were suboptimal for males or because foraging by females at South Georgia causes local depletion of food, and males, which have the option to forage further afield, can forage more successfully in regions where there are no females. Comparison with fisheries data also suggests that these fur seals are targeting the most abundant exploitable prey.

Thls study examned the relahve contribution of environmental varlatlon and the seasonal demands of pup reanng on the foraging behav~our of female Antarctic fur seals Arctocephalus gazella dl Blrd Island, South Georgla (54"S, 38"W), dunng 3 austral summers (1994 to 1996) Time-depth recorders measured the diving behaviour of 72 ~ndlvlduals during a total of 385 foraging tnps totalling 1964 d at sea. The frequenc~es of knll, flsh and squld In the dlet were estimated from prey items contained in scats In 1996, a year of hlgh knll abundance, femaldsmade shorter foraging tnps, fewer dives and spent more time ashore than In 1994 when krdl was scarce Females fed exclusively on krill in 1996, and frequent shallow daytime divingindkcated that krlll were close to the surface during the day In 1994 and 1995 deeper and longer-duration daytlme d~ves were associated wlth a higher proportion of fish and squid In the diet Foraglng trip durat~on. ashore duration and d~v e frequency increased through the course of the 1995 and 1996 lactation seasew. Females, therefore, appeared to match pup demands by increasing both time feeding at Sea and energy dellvery to the pup on land However, the ~mporta.",ce of sea su:!acc :empera:uie c,nd d~r a i l u l~ ui 111yht in muinpla regression models suggested that physical factors were also impoltant In explaining the seasonal pattern of fur seal foiaging behaviour

The impact of lubricants on energy efficiency is considered. Molecular details of base oils used in lubricants can have a great impact on the lubricant's physical properties which will affect the energy efficiency performance of a lubricant. In addition, molecular details of lubricant additives can result in significant differences in measured friction coefficients for machine elements operating in the mixed/boundary lubrication regime. In single machine elements, these differences will result in lower friction losses, and for complete systems (such as cars, trucks, hydraulic circuits, industrial gearboxes etc.) lower fuel consumption or lower electricity consumption can result.

Seasonal haul-out patterns and diet of individually marked leopard seals (Hydrurga leptonyx) were investigated at Bird Island, South Georgia during the 1983–96 winters. A total of 2956 leopard seal sightings were made, and 121 seals were tagged during the study, mainly between 1993 and 1996. Photographs of scars and pelage patterns were also used to identify a subset of these individuals across years, which provided no evidence of tag loss between or within years. Leopard seals were observed between April and November; the mean time between the first and last sightings in each year was 208 d (s d ± 48). Between 1993–96, eight seals were resident around the island for more than 100 d, and the longest recorded residence was 130 d. The proportion of tagged seals resighted was 0.35 and 0.17 in 1995 and 1996 respectively. Based on estimates of body length, <5% of the seals were juveniles (0–1 years) and >70% were not sexually mature. There was considerable inter-annual variation in abundance, with a maximum of 502 sightings during 1994, compared with a minimum of 21 during 1986 and 1989. Antarctic fur seals (Arctocephalus gazella) were the main prey item (58% of kills observed and 53% of scats). Other items included penguins (28% of kills observed and 20% of scats) and fish (24% of scats). Antarctic krill (Euphausia superba), southern elephant seals (Mirounga leonina) and seabirds other than penguins were also present in the diet in small quantities.

The diving behaviour of Antarctic fur seal (Arctocephalus gazella) pups on Bird Island, South Georgia (54°S, 38°W), was examined during February-April 1996 using capillary-tube depth gauges (CDGs) and time-depth recorders (TDRs). CDGs were deployed on 6 female and 10 male pups aged 65-101 days. Depths measured by CDGs were within 10% of maximum depths recorded by TDRs. Maximum dive depths averaged 13.8 m and ranged from 4.2 to 28.1 m. Body length alone accounted for 66% of the total variation in maximum dive depth. TDRs were deployed on one female and two male pups aged 89-101 days. In total, 4858 dives were recorded during 173 h at sea. The average dive depth and duration was 4.2 m and 20 s, respectively. Pups made a total of 34 trips and each spent 50% of its time at sea. Not all trips included dives; however, when diving took place trips lasted, on average, 6.8 h and contained 214 dives, most of which took place during daylight. Dives were made at a frequency of 30/h and the vertical distance dived was 124 m · h-1. The number of dives, percentage of time spent submerged, percentage of time spent diving, dive frequency, and dive rate were positively correlated with trip duration. These results show that Antarctic fur seal pups develop diving skills at an early age, and by the time they are close to being weaned they have the diving ability to exploit prey similar to those taken by adults.

No abstract

There is currently a strong focus on producing increasingly fuel-efficient vehicles, both to help meet CO 2 emissions reductions targets arising from the Kyoto Agreement on climate change, and, in certain countries, to avoid large government-imposed financial penalties. This paper reviews the role that lubricants can play in reducing a vehicle's fuel consumption. The paper reviews the lubricant factors that affect fuel consumption. The paper also reviews a number of engine friction models, which help to give insight into the relative importance of the different engine components to total engine friction. The paper reviews how these models compare with results from the European and US passenger car standard fuel economy engine tests now in place. The paper also reviews the issues surrounding engine durability with the lower-viscosity fuel economy lubricants that are now being developed. The majority of the paper is concerned with fuel economy in passenger car vehicles, but there is also some discussion of the issues surrounding improved fuel economy in heavy-duty diesel trucks.

A detailed analysis of ‘squeeze’ lubrication effects in piston rings and reciprocating line contacts is reported. Inclusion of ‘squeeze’ effects leads to significant oil film thicknesses at reversal positions, and the pressure distribution in the lubricated contact can extend over the full face of the contact, whereas in models which neglect ‘squeeze’ effects, oil film thicknesses are predicted to be zero at reversal positions, and only half the contact is wetted. If it is desired to reduce friction losses without affecting durability, it is shown that one interesting ‘co-engineering’ option would be to use a lower viscosity lubricant, and at the same time, use ‘flatter’ piston rings. This is shown to lead to both lower friction and higher oil minimum film thicknesses. The model developed for piston rings can be applied to reciprocating line contacts with very little modification, and once again, it is found that the inclusion of ‘squeeze’ effects has a significant impact on oil film thickness, and it is also shown that the friction force is different dependent on the direction of sliding of the contact.