A statistical appraisal on accuracy of smartphone location services: a case study at the University of Moratuwa, Sri Lanka

Smartphones have become an essential companion in most of the communities. Yet, we may not be quite aware of the capabilities and services that these devices could provide. As a result, features such as location services are underutilized and mostly used for navigation and location sharing. This study explores the limitations of embedded GPS receivers in smartphones with reference to the performance of a consumer-grade hand-held GPS device. The location coordinates obtained with the GPS unit and six smartphones on five locations over ten consecutive days revealed that over 70% of smartphone records provide the location coordinates within 0 to 10 m accuracy. Furthermore, at certain locations, over 75% of records have maintained the coordinate accuracy within 0 to 5 m. Hence, the use of smartphone location information in place of standalone GPS readings, can be recommended for moderate location accuracy requirements, such as geo-tagged data collection. Nevertheless, hand-held GPS units provide better approximations than the smartphones, for elevation readings at the studied locations. Accordingly, further investigations are recommended, to evaluate the discrepancies in elevation records, provided the ambiguities generated while recording the elevation measurements from the hand-held GPS units are minimized

Applicability of pre-heating techniques for recovery of garnet from garnet biotite gneiss

In mineral processing industry, the highest energy is consumed by crushing and grinding operations. However, if we can initiate micro cracks in the hard rock pieces in advance, we should be able to reduce the crushing energy and liberate useful minerals economically. Various pre-heating techniques have been tried by the scientists around the world to liberate minerals from rocks. In this investigation, pre-heating techniques were used to liberate Garnet from Garnet Biotite Gneiss. The market price of Garnet varies with the particle size. Hence, the samples were crushed and sized into industry needed three size fractions: (+250-850) μm, (+180-250) μm and (-180) μm. Afterwards, by means of Wilfley Table, Garnet was separated from rocks. Final Garnet recovery percentage was recorded for different temperatures. Furthermore, energy calculation was done for each sample to get an idea about the power consumption. It was observed that the crushing strength decreases with the temperature increment and it has been proven by identifying propagation of micro cracks in thin sections, prepared from rock samples pre-heat treated in Muffle Furnace and Microwave Oven. The analysis reveals that the preheat treated and quenched samples give higher Garnet recovery than Garnet recovered from as-received samples of Garnet rich Biotite Gneiss