Abstract: To determine a corrected flow rate value of a mobile phase flowing in a liquid chromatography (LC) system, a flow rate of the mobile phase at a selected reference position in the LC system is measured to produce one or more flow rate values. A model of the LC system is applied to the flow rate value(s) to determine the corrected flow rate value(s). The model includes a distribution of capacitive elements and resistive elements arranged according to a topology of the LC system. The capacitive and resistive elements are representative of system and solvent properties affecting flow rate while operating the LC system. The system and solvent properties may be properties affecting the flow rate while operating the LC system under dynamic conditions.

Abstract: To determine a corrected flow rate value of a mobile phase flowing in a liquid chromatography (LC) system, a flow rate of the mobile phase at a selected reference position in the LC system is measured to produce one or more flow rate values. A model of the LC system is applied to the flow rate value(s) to determine the corrected flow rate value(s). The model includes a distribution of capacitive elements and resistive elements arranged according to a topology of the LC system. The capacitive and resistive elements are representative of system and solvent properties affecting flow rate while operating the LC system. The system and solvent properties may be properties affecting the flow rate while operating the LC system under dynamic conditions.

Abstract: A pump unit comprises a primary piston pump, a secondary piston pump, and a flow path adapted for fluidically connecting in series the primary piston pump and the secondary piston pump. The pump unit's duty cycle comprises a delivery-and-fill phase, in which the primary piston pump supplies a flow of liquid to the secondary piston pump, and during the delivery-and-fill phase, the flow of liquid supplied by the primary piston pump is partly used for filling up the secondary piston pump and partly used for maintaining another flow of liquid dispensed across the secondary piston pump. The flow path comprises a heat exchanger, wherein liquid supplied by the primary piston pump passes through the heat exchanger before being supplied to the secondary piston pump.

Abstract: A method for controlling operation of a pump unit, where the pump unit includes a primary piston pump having a primary piston and a secondary piston pump having a secondary piston. The primary piston pump is fluidically connected with the secondary piston pump. The primary piston pump includes an inlet valve and an outlet valve, and the pump unit operates periodically according to a pump cycle. The method includes determining a fluid pressure of fluid dispensed by the pump unit, and performing a closed loop control of a position of the primary piston in dependence on the fluid pressure of the fluid dispensed by the pump unit during a first time interval of the pump cycle.

Abstract: Electronic or computer-implemented systems and methods for allowing an investment advisor or user to evaluate one or more financial products offered by one or more providers of financial products, involving electronic configuration of a set of required and a set of preferred questions and corresponding appropriate answers for each of the questions in these sets, electronic configuration of weights for each of the questions in the set of preferred questions, electronically provided responses to at least some of the questions, electronic comparison of the appropriate answers and the responses, electronic calculation of preferred, required and combined scores, and electronic presentation of the combined scores to the investment advisor or user. Electronic or computer-implemented systems and methods for the generation of requests for proposals and reports based upon the scores obtained.

Abstract: A method for controlling operation of a pump unit, where the pump unit includes a primary piston pump having a primary piston and a secondary piston pump having a secondary piston. The primary piston pump is fluidically connected with the secondary piston pump. The primary piston pump includes an inlet valve and an outlet valve, and the pump unit operates periodically according to a pump cycle. The method includes determining a fluid pressure of fluid dispensed by the pump unit, and performing a closed loop control of a position of the primary piston in dependence on the fluid pressure of the fluid dispensed by the pump unit during a first time interval of the pump cycle.

Abstract: A method for metering two or more liquids in controlled proportions in a liquid supply system and for supplying a resultant mixture, in which the liquid supply system includes a plurality of solvent supply lines, a proportioning valve interposed between the solvent supply lines and an inlet of a pumping unit, the method includes drawing in a first liquid into the pumping unit via a first solvent supply line; determining one or more switching points of time for switching between different solvent supply lines, the switching points of time being determined in a way that at said switching points of time, the liquid supplied to the pumping unit is in a predefined pressure range; switching from the first solvent supply line to a second solvent supply line at one of said switching points of time; drawing in a second liquid into the pumping unit via the second solvent supply line.

Abstract: A method for controlling operation of a pump unit, where the pump unit includes a primary piston pump having a primary piston and a secondary piston pump having a secondary piston. The primary piston pump is fluidically connected with the secondary piston pump. The primary piston pump includes an inlet valve and an outlet valve, and the pump unit operates periodically according to a pump cycle. The method includes determining a fluid pressure of fluid dispensed by the pump unit, and performing a closed loop control of a position of the primary piston in dependence on the fluid pressure of the fluid dispensed by the pump unit during a first time interval of the pump cycle.

Abstract: A pump unit comprises a primary piston pump, a secondary piston pump, and a flow path adapted for fluidically connecting in series the primary piston pump and the secondary piston pump. The pump unit's duty cycle comprises a delivery-and-fill phase, in which the primary piston pump supplies a flow of liquid to the secondary piston pump, and during the delivery-and-fill phase, the flow of liquid supplied by the primary piston pump is partly used for filling up the secondary piston pump and partly used for maintaining another flow of liquid dispensed across the secondary piston pump. The flow path comprises a heat exchanger, wherein liquid supplied by the primary piston pump passes through the heat exchanger before being supplied to the secondary piston pump.

Abstract: A method for controlling operation of a pump unit, where the pump unit includes a primary piston pump having a primary piston and a secondary piston pump having a secondary piston. The primary piston pump is fluidically connected with the secondary piston pump. The primary piston pump includes an inlet valve and an outlet valve, and the pump unit operates periodically according to a pump cycle. The method includes determining a fluid pressure of fluid dispensed by the pump unit, and performing a closed loop control of a position of the primary piston in dependence on the fluid pressure of the fluid dispensed by the pump unit during a first time interval of the pump cycle.

Abstract: A flow meter with a metering device for intaking and metering a defined volume of a fluid, and with a control unit for controlling the fluid intake of the metering device for determining a flow rate of the fluid.