PhD Diary - Exploration Geophysics

'Cation exchange capacity' (CEC), is a term that gets thrown around when discussing the electrical properties of clays, but what does it actually mean? The literal definition is:  "...the number of exchangeable cations per-dry-weight that a soil is capable of holding, and available for exchange with the soil water solution." What does this actually mean? Going right back to basics, charges can be divided in anions (an-eye-ən) and cations (kat-eye-ən), representing negative and positively charged ions , or ' non-equally charged atom or molecule ', respectively. A high cation-exchange-capacity therefore means there is a large number of positively charged, mobile ions available to 'exchange' with other ions. What about the physical values? Soil colloid — CEC meq/100 g Sesquioxides — 0–3 Kaolinite — 3–15 Illite — 25–40 Montmorillonite — 60–100 Vermiculite — 80–150 Humus — 100–300 Table from Wikipedia (https://en.wikipedia.org/wiki/Ca

I bought a car. It's a Mitsubishi Lancer CJ ES Sport 2014 model, and features a continuously variable transmission (CVT) drive train. The CVT is quite interesting. Very simple in theory. CVT makes for optimal tuning between the smaller pulley piston, reducing flow amount of oil pump, and the direct control torque converter by which an efficient engine output transfer and a smooth ride are realized. Based on accelerator travel information from actual drivers under actual driving conditions, the system controls to obtain the driving force in accordance with the driving situation, at the optimal efficiency point of the engine and the CVT. This enables a supple and smooth driving feel under all driving conditions while also achieving low fuel consumption. Sounds like nonsense and advertising spin. This picture explains it much better. The gear ratio is adjusted via continuously increasing or decreasing the radius of the gear to maintain the most efficient power deliv

La Nina and El Nino events are not actually related to Perth. To be more specific (or should I say, 'Pa-cific'), they're associated with the cooling or heating of the Pacific ocean surface temperature, where the result is an increase or decrease in the convection cell driving localised rainfall. The differential temperatures strongly affects the location and amount of rainfall (amongst other things) found at the increasing gradient of the cell. The Bureau of Meteorology has a nice picture describing the phenomenon, The dominant weather pattern affecting Perth's climate is the 'West Trough', and to a lesser extent, the 'Indian Ocean Dipole'. In fact, there are a vast number of weather patterns which all affect Perth, to some extent. The recent weather is highly erratic, breaking the record for coolest January, and 6th wettest on record.  A combination of tropical lows, and a shift in the sub-tropical ridge are generally believed t