Abstract: An elution apparatus and a detection apparatus are described. The elution apparatus includes: a sample trap for trapping a sample; and one or more pumps and/or valves to move a liquid eluent and a liquid eluate, wherein the eluate includes an extracted portion of the sample that is extracted by the eluent. The detection apparatus includes: a capillary having a low-voltage (LV) end portion to receive a sample; and a conductivity detector coupled to a high-voltage (HV) end portion of the capillary to generate signals based on conductivity of a monitored portion of the capillary in the HV end portion, wherein the conductivity detector is electrically isolated from the LV end portion.

Abstract: An elution apparatus and a detection apparatus are described. The elution apparatus includes: a sample trap for trapping a sample; and one or more pumps and/or valves to move a liquid eluent and a liquid eluate, wherein the eluate includes an extracted portion of the sample that is extracted by the eluent. The detection apparatus includes: a capillary having a low-voltage (LV) end portion to receive a sample; and a conductivity detector coupled to a high-voltage (HV) end portion of the capillary to generate signals based on conductivity of a monitored portion of the capillary in the HV end portion, wherein the conductivity detector is electrically isolated from the LV end portion.

Abstract: An elution apparatus and a detection apparatus are described. The elution apparatus includes: a sample trap for trapping a sample; and one or more pumps and/or valves to move a liquid eluent and a liquid eluate, wherein the eluate includes an extracted portion of the sample that is extracted by the eluent. The detection apparatus includes: a capillary having a low-voltage (LV) end portion to receive a sample; and a conductivity detector coupled to a high-voltage (HV) end portion of the capillary to generate signals based on conductivity of a monitored portion of the capillary in the HV end portion, wherein the conductivity detector is electrically isolated from the LV end portion.

Abstract: A method is described for controlling a plurality of parallel-connected power converters 20a, 20b, each of which operates in accordance with a pulse width modulation (PWM) strategy defined by an independent voltage carrier signal and an independently controllable modulating sinusoidal voltage signal which are used to generate a PWM command signal for each PWM strategy. The voltage carrier signals of the PWM strategies have the same switching period and desynchronisation of the PWM command signals causes an unwanted circulating current to flow between the power converters 20a, 20b. The method thus comprises providing the independently controllable modulating sinusoidal voltage signal of the PWM strategy of at least one of the plurality of power converters 20a, 20b with a dc voltage offset to modify the PWM command signal of the at least one power converter and thereby increase the synchronisation of the PWM command signals so that the magnitude of any unwanted circulating current is reduced.

Abstract: A method is described for controlling a plurality of power converters 1, 2 connected in parallel between an ac arrangement 12 and a common dc link 16, each of the power converters 1, 2 operating in accordance with a pulse width modulation (PWM) strategy and having an independently variable dc link reference voltage. The method comprises modifying an output voltage droop characteristic of at least one of the plurality of parallel-connected power converters 1, 2 by varying the dc link reference voltage of the at least one power converter 1, 2 based on the output current of the at least one power converter 1, 2 and the average of the output currents of the plurality of power converters 1, 2.

Abstract: A method is described for controlling a plurality of parallel-connected power converters 20a, 20b, each of which operates in accordance with a pulse width modulation (PWM) strategy defined by an independent voltage carrier signal and an independently controllable modulating sinusoidal voltage signal which are used to generate a PWM command signal for each PWM strategy. The voltage carrier signals of the PWM strategies have the same switching period and desynchronisation of the PWM command signals causes an unwanted circulating current to flow between the power converters 20a, 20b. The method thus comprises providing the independently controllable modulating sinusoidal voltage signal of the PWM strategy of at least one of the plurality of power converters 20a, 20b with a dc voltage offset to modify the PWM command signal of the at least one power converter and thereby increase the synchronisation of the PWM command signals so that the magnitude of any unwanted circulating current is reduced.

Abstract: An environmentally resilient building product of a vinyl laminated formed-sheet metallic substrate wherein the vinyl laminate is adhesively attached to the formed-sheet metallic substrate to provide a durable and attractive surface. Possible decorative and resilient surfaces include, but are not limited to solid colors, metallic finishes, and graphical images or patterns, all available in a variety of textures.

Abstract: A method and a liquid scintillation counter for measuring a sample, a mixture of the specimen to be analysed and a scintillator, in a liquid scintillation counter where the sample (14) is measured with two photo multiplier tubes (23, 24) situated on different sides of the sample. The photo multiplier tubes situated on different sides of the sample operate in coincidence. Asymmetric samples are measured in such a way that the counting efficiency is measured with the photo multiplier tubes (23, 24) operating in coincidence ad calculated using the amount of coincidence pulses, whereas the amplitude and the pulse height distribution are measured only with one photo multiplier tube (23 or 24).

Abstract: Polymerization of vinyl chloride in aqueous suspension using a polymerization reactor having adherently deposited on internal surfaces thereof a build-up suppressant coating comprising a product of build-up suppressant activity formable by (and preferably formed by) the condensation of an effective 1-naphthol (preferably 1-naphthol itself) and formaldehyde. The condensation is preferably effected in a base-catalyzed reaction; it may also (less preferably) be effected in an acid-catalyzed reaction. The coating product itself and a process for its production are also claimed.

Abstract: Aromatic polyethersulphones that are particularly useful as adhesives and coatings having end groups of formula --OCH.sub.2 COR, where R is alkyl or alkoxy. Preferred examples are --OCH.sub.2 COCH.sub.3 and --OCH.sub.2 COOC.sub.2 H.sub.5. Such polymers may be made by heating polyethersulphones made from halophenates or bisphenate/dihalide mixtures, in the presence of a reagent of formula XCH.sub.2 COR (X is halogen, preferably chlorine), such as chloroacetone or ethyl chloroacetate, for a short period of time. Such polymers of molecular weight (RV<0.25) are of particular use in coating compositions comprising a dispersion of a fluorocarbon polymer dispersed in a solution or dispersion of the polyethersulphone.

Abstract: A radio communications system for aircraft, particularly useful at UHF frequencies and in aircraft travelling at high speed and low level where rapid phase and amplitude fluctuations degrade intelligible speech transmission. The system comprises a transmitter in a first aircraft, the transmitter including an upshift frequency translator for transferring the frequency band of an input signal from a microphone to a higher band, and further including an amplitude modulator for modulating the frequency translated signals; and a receiver in a second aircraft arranged to receive and demodulate the transmitted signals, the receiver including a high pass filter for removing noise from the demodulated signal, and a downshift frequency translator for transferring the frequency band of the filter output to a lower band.