Abstract: Detecting network congestion at a network device by collecting, for various time intervals, measurements of a quantifiable characteristic of traffic transiting the network device at a plurality of respective measurement times during each of the time intervals. Described systems and methods select two or more sets of measurements, each set corresponding to a respective time interval; determine, for each of the selected sets of measurements, respective upper and lower boundaries for the quantifiable characteristic during the respective time interval; and analyze trends for a time window inclusive of the time intervals corresponding to the selected sets of measurements, the trends including an upper boundary trend and a lower boundary trend. Congestion is then identified responsive to the analysis detecting a substantially constant upper boundary trend concurrent with a rising lower boundary trend.

Abstract: A cellulosic cationic ion-exchange composition is formed by sulfonation of activated cellulose having of high surface area characteristics, using an acid such as concentrated H.sub.2 SO.sub.4. The sulfonated material is convertible into different forms, viz., H-form, Na-form, K-form, NH.sub.4.sup.+ form, Ba-form, Ca-form, and Cu-form by appropriate reaction. The cation-exchanger has been found useful to treat industrial effluents for the removal of heavy metals, to achieve recovery of precious metals, to carry out water-softening, and the like.