Abstract: The invention relates to a modem and a method for providing bit loading computation in a multi-carrier communication system, using a plurality of simultaneous different carriers or tones by measuring the signal to noise ratios (SNRs) for carriers and by determining in dependence of the SNR a related number of bits to be allocated to the respective carrier. The method comprises the steps of providing a sliding window having a frequency width able to contain a predetermined number of the carriers, moving the sliding window over the frequency spectrum of the carriers through a plurality of positions of the window with respect to the carrier frequencies, and when the window contains the predetermined number of the carriers and there is at least one further carrier to be positioned in the window as a new carrier for bit allocation, the window is moved such that on entering a new carrier into the window at one of its borders, a carrier already in the window at the other frequency border leaves the window.

Abstract: A method for regenerating deactivated sulfonated cation exchange catalysts comprises washing the deactivated catalyst with phenol-water mixtures comprising about 5-20 wt. % of water in phenol at a temperature of about 70-95° C.

Abstract: The invention is a catalytic ion exchange resin bed with low pressure drop, low catalyst breakage and low catalyst deactivation as well as an improved process for the production of bisphenol A employing such a catalytic ion exchange resin bed.

Abstract: The invention is a catalytic ion exchange resin bed with low pressure drop, low catalyst breakage and low catalyst deactivation as well as an improved process for the production of bisphenol A employing such a catalytic ion exchange resin bed.

Abstract: Acidic impurities in dihydroxyaromatic compounds such as bisphenol A, as illustrated by sulfonic acids and mercaptocarboxylic acids, can have an adverse effect on the molecular weight of a polycarbonate prepared therefrom by transesterification. The same is true of acidic impurities in diaryl carbonates such as diphenyl carbonate, as illustrated by salicylic acid and ferric chloride. The reagents are analyzed for these impurities. Based on the analysis, the reagents are discarded or recycled, or a compensatory amount of alkali metal hydroxide is employed as a catalyst in the reaction.

Abstract: An integrated process for the preparation and recovery of BPA in pure form utilizes a series of steps to crystallize the 1:1 adduct of phenol and bisphenol-A, with periodic descaling of the crystallizer surfaces with a modified reactor/crystallizer containing 1 to 40 percent water.

Abstract: Display rack for shelves comprising a base designed to constitute a storage plane for objects of various widths. The base is composed of a plurality of juxtaposed elements and at least one sliding rim. Each of the juxtaposed elements comprises a first edge and a second edge formed in such a way that they can accommodate the sliding rim.