Mammalian and avian diversity of the Rewa Head, Rupununi, Southern Guyana

We report the results of a short expedition to the remote headwaters of the River Rewa, a tributary of the River Essequibo in the Rupununi, Southern Guyana. We used a combination of camera trapping, mist netting and spot count surveys to document the mammalian and avian diversity found in the region. We recorded a total of 33 mammal species including all 8 of Guyana's monkey species as well as threatened species such as lowland tapir (Tapirus terrestris), giant otter (Pteronura brasiliensis) and bush dog (Speothos venaticus). We recorded a minimum population size of 35 giant otters in five packs along the 95 km of river surveyed. In total we observed 193 bird species from 47 families. With the inclusion of Smithsonian Institution data from 2006, the bird species list for the Rewa Head rises to 250 from 54 families. These include 10 Guiana Shield endemics and two species recorded as rare throughout their ranges: the harpy eagle (Harpia harpyja) and crested eagle (Morphnus guianensis).

KEPADATAN DAN FREKUENSI JENIS BURUNG PEMANGSA DI HUTAN GUNUNG EMPUNG, TOMOHON, SULAWESI UTARA

Tujuan penelitian ini adalah untuk menentukan kepadatan dan frekuensi jenis-jenis burung pemangsa yang hidup di hutan Gunung Empung, Tomohon, Sulawesi Utara. Penelitian ini dilaksanakan selama kurang lebih 2 bulan, yaitu dari awal bulan Oktober hingga akhir November 2010. Penelitian ini menggunakan metode Titik Hitung yang ditempatkan secara acak mulai dari ketinggian 1000 m di atas permukaan laut (dpl) hingga ke puncak gunung. Hasil penelitian menunjukkan bahwa di hutan Gunung Empung terdapat 3 jenis burung pemangsa, yaitu Accipiter griseiceps, Accipiter gularis dan Milvus migrans. Burung pemangsa dengan kepadatan tertinggi adalah Milvus migrans, sedangkan burung pemangsa dengan frekuensi kehadiran tertinggi adalah Accipiter gularis. DENSITY AND FREQUENCY OF RAPTORS SPECIESAT MOUNT EMPUNG’S FOREST, TOMOHON, NORTH SULAWESIABSTRACTThe aim of this research was to determine the density and frequency of raptors at Mount Empung, Tomohon, North Sulawesi. This research was carried out for approximately 2 months, from early October until the end of November 2010. The method used for this research was Spot Count Method that was randomly placed from the altitude 1000 m above the sea surface to the top of the mount. The result showed that 3 species of raptors inhabited Empung’s forest, i.e. Accipiter griseiceps, Accipiter gularis and Milvus migrans. Raptor with the highest density rate was Milvus migrans, whereas the most frequent raptor was Accipiter gularis.

A Tribological Investigation of Carbon-Carbon Composites and the Effect of Roughness and Waviness Parameters on Friction Performance

Friction tests for two types of carbon-carbon (C-C) composites were performed using a sub-scale aircraft brake dynamometer for 100 stops. Worn surface profiles were measured using a surface profilometer. Roughness and waviness parameters from the profilometry measurements were compared to weight loss, thickness loss, effectiveness, stop time, and torque for each C-C composite type. The results show that when roughness is analyzed, for an increase in torque and effectiveness and a decrease in stop time, there is a decrease in skewness and high spot count; and an increase in maximum valley depth, mean spacing of local peaks, and mean arithmetic wavelength. For waviness profiles, for an increase in torque and effectiveness and a decrease in stop time, there is a decrease in skewness; and an increase in high spot count, maximum valley depth, mean spacing of local peaks, and mean arithmetic wavelength. Furthermore, there are differences in both friction performance and surface topography between the CC composite types which can be attributed to the differences in fiber orientation and microstructure at the wear surfaces.

Paper 11: Mathematical Expression of Surface-Finish Characteristics

Recent developments in mechanical engineering technology have highlighted the inadequacy of the existing criteria of surface classification. It has been suggested that a bearing area curve and a high spot count are more satisfactory criteria than those utilized hitherto. Research into fields such as the stiffness of plane joints has indicated the validity of these criteria. In order to obtain a quantitative prediction of the magnitude of such parameters it is necessary to endow surfaces with certain mathematical properties. This paper is intended to indicate methods whereby this may be achieved.