Abstract: The position of the focus of a laser beam arrangement relative to a reference surface is determined by (A) irradiating a laser beam on the reference surface, (B) measuring the intensity of reflection light generated by the surface due to the laser beam, wherein in (C), (A) and (B) are repeated for a plurality of different, effective distances between the surface and the arrangement, and (D) that effective distance is determined as the focal distance representative for the position of the focus for which the measured or an interpolated intensity of reflection light is extremal, if, (E) every time (A) and (B) are performed, the arrangement and surface are moved relative to each other so the laser beam sweeps across a surface area of the reference surface that has a stronger direct reflection and weaker diffuse reflection, and sweeps across a structure formed in its interior that has a stronger diffuse reflection and weaker direct reflection.

Abstract: Methods for reducing response time of membrane based electrochemical cells. A probe correction factor is calculated based on a percent rate of change in probe signal with time. A staged correction may be applied such that as signal change gets smaller, the effect of the compensation is reduced to prevent over shoot on the calculated residual. Control systems and techniques can regulate or control operations of a water treatment system.

Abstract: 3-methacryloxy- and 3-acryloxyisobutylalkoxysilanes of the general formula (I) and R is a linear alkyl radical having from 1 to 4 carbon atoms, R1 is a linear or branched alkyl radical having from 1 to 3 carbon atoms, and m is 0 or 1.