Acids are either “strong” or “weak.” This relates to the amount of free hydrogen ions in the solution of a given concentration. Thus, nitric acid is a strong acid, since all of the nitric-acid molecules are dissociated into active hydrogen ions and nitrate ions. However, acetic acid is a weak acid. A solution of acetic acid of the same molar concentration as nitric acid would have a very differ...

Electronic control over the generation, transport, and delivery of ions is useful in order to regulate reactions, functions, and processes in various chemical and biological systems. Different kinds of ion diodes and transistors that exhibit non-linear current versus voltage characteristics have been explored to generate chemical gradients and signals. Bipolar membranes (BMs) exhibit both ion c...

This paper reports an innovative method based on electrochemistry to adjust the pH in nutrient solutions used in hydroponics. The required quantity of H or OH ions is produced insitu through electrolytic water decomposition. Because the direction and rate of electrochemical reactions can be easily manipulated by controlling the polarity and voltage applied between electrodes, the most important...

A fuzzy controller f o r a neutralization process is described. The controller was set up fo r a laboratory pilot plant. The approach is shown to be effective and can be extended to highly nonlinear and nonstationary processes. The "operator" knowledge encoded in the rules was obtained by several experimental runs o f the system using manual control. Rules are composed using the max-min composi...

Despite diverse and changing extracellular environments, fungi maintain a relatively constant cytosolic pH and numerous organelles of distinct lumenal pH. Key players in fungal pH control are V-ATPases and the P-type proton pump Pma1. These two proton pumps act in concert with a large array of other transporters and are highly regulated. The activities of Pma1 and the V-ATPase are coordinated u...

This paper presents a novel nonlinear Internal Model Controller architecture that achieves linear rejection of input disturbances from the control signal. For a large class of SISO nonlinear systems, appropriate open loop stability properties guarantee closed loop tracking and disturbance rejection of asymptotically constant signals. The convenient tuning and improved performance is illustrated...

An active modal-fuzzy control method using hydraulic actuators is presented for seismic response reduction. In the proposed control system, a new fuzzy controller designed in the modal space produces the desired active control force. This type controller has all advantages of the fuzzy control algorithm and modal approach. Since it is very difficult to select input variables used in fuzzy contr...

The paper addresses control related design issues for neutralization plants. Mainly for control reasons, the neutralization is usually performed in several steps (mixing tanks) with gradual change in the concentration. The aim is to give recommendations for issues like tank sizes and number of tanks. Assuming strong acids and bases, we derive linearized relationships from the disturbance variab...