ESTIMATION OF pH OF SUGAR CANE JUICES A . T HIGH TEMPERATURE
A Philips digital pH-meter (PW9422) equipped with a Philips high temperature pH-electrode (CH 85D-SD) and platinum 100 thermometer was used in the autocalibrate mode to standardise itself using 2 NBS-buffers (phthalate and borax solutions). The instrument automatically identifies each buffer and uses the current temperature to select the exact buffer value from its look-up table. Temperature compensation for electrode slope changes due to temperature changes was also automatic.
INVESTIGATIONS OF UNDETERMINED LOSSES AT PONGOLA
A review of the history of undetermined loss at Pongola showed that the problem began in about 1974 and grew steadily. Major factory modifications took place just prior to 1974 but the dominant cane variety also changed at this time and the use of variety NCo 376 increased in parallel with the undetermined loss. The loss has shown a seasonal trend with maxima at the beginnings and ends of seasons. Weekly measurements of sucrose lost from the stage between mixed juice and syrup showed that usually more than 50%, and sometimes more than 80%, of the undetermined loss occurred from this stage. When particularly high loss occurred however it was mainly from a stage after syrup. Very high losses invariably occurred only in the late season. In the laboratory, composite weekly samples of late season molasses.evolved gas at a rate which correlated with the factory undetermined loss. Some samples of late season syrups lost sucrose at unexpectedly high rates when heated at 70°C for 48 hours, and the losses correlated with those measured in the factory. No such correlations were evident for mid-season samples.
When to Cross the Spread? Trading in Two-Sided Limit Order Books
In this paper the problem of optimal trading in illiquid markets is addressed when the deviations from a given stochastic target function describing, for instance, external aggregate client flow are penalized. Using techniques of singular stochastic control, we extend the results of [F. Naujokat and N. Westray, Math. Financ. Econ., 4 (2011), pp. 299--335] to a two-sided limit order market with temporary market impact and resilience, where the bid ask spread is now also controlled. In addition to using market orders, the trader can also submit orders to a dark pool. We first show existence and uniqueness of an optimal control. In a second step, a suitable version of the stochastic maximum principle is derived which yields a characterization of the optimal trading strategy in terms of a nonstandard coupled forward-backward stochastic differential equation (FBSDE). We show that the optimal control can be characterized via buy, sell, and no-trade regions. The new feature is that we now get a nondegenerate no-...