A device and a method for repeatedly modifying the composition of a fluid. The device includes a first module (19) modifying the composition of the fluid, a second module (21) modifying the composition of the fluid and a dwell module (20) with an inlet (8) and an outlet (10). The first module is connected in a fluid-conducting manner to the dwell module inlet and the dwell module outlet is connected in a fluid-conducting manner to the second module. Either the first or the second module is a filter unit, or the first module is a first filter unit and the second module is a second filter unit. The filter unit(s) include(s) at least one first filter medium (4, 14) delimiting a supply channel (2, 12) and a retentate channel (1, 11) and at least one second filter medium (5, 15) delimiting the retentate channel and a permeate channel (3, 13).

Systems and methods are described for automatically adjusting the composition of a spray chamber matrix gas flow coordinated with an analysis of a particular chemical element or groups of elements. A system can include a spray chamber configured to be coupled to an analytical system, the spray chamber having a nebulizer gas port configured to receive a nebulizer gas; and an inlet for receiving a gas from at least one gas source. The system also includes a controller operably coupled to the spray chamber, the controller configured to adjust a gas flow rate of the gas from the at least one gas source in coordination with analysis of a particular chemical element by the analytical system.

Systems and methods are described for automatically adjusting the composition of a spray chamber matrix gas flow coordinated with an analysis of a particular chemical element or groups of elements. A system can include a spray chamber configured to be coupled to an analytical system, the spray chamber having a nebulizer gas port configured to receive a nebulizer gas; and an inlet for receiving a gas from at least one gas source. The system also includes a controller operably coupled to the spray chamber, the controller configured to adjust a gas flow rate of the gas from the at least one gas source in coordination with analysis of a particular chemical element by the analytical system.

The present invention relates to a method of controlling prepurifier cycle time by monitoring ambient CO.sub.2 level in order to prevent CO.sub.2 breakthrough occurrences caused by extreme instantaneous variations in ambient CO.sub.2 level. Rather than operating solely by prepurifier design bed capacity, the method of the invention continuously updates bed capacity for the contaminants using the feed temperature, pressure and contaminants composition, calculating the total amount of contaminants that were fed to the prepurifier during the feed step and estimates the perturbation front velocity, i.e., the velocity at which the contaminants front coming from an extreme instantaneous variations of ambient level is going to propagate inside the adsorbents bed. Estimating the perturbation front velocity allows for a more precise estimate of the maximum time remaining for the feed step before starting to experience CO.sub.2 breakthrough. This eliminates the need to switch the online bed unnecessarily early and risking shorter regeneration for the offline bed.

Total ammonia nitrogen in a volume of sludge in an aeration tank is measured and compared to a target ammonia nitrogen setpoint to calculate an airflow target for adjusting the measured total ammonia nitrogen toward the target ammonia nitrogen setpoint. The airflow target may be an airflow rate or, for an SBR, an airflow duration, and airflow into the aeration tank is adjusted according to the airflow target. A target solids retention time setpoint is also calculated from information relating to the airflow target and the solids retention time is adjusted toward the target solids retention time setpoint. The waste activated sludge flow rate for the aeration tank may be adjusted to adjust the solids retention time for the aeration tank toward the target solids retention time setpoint.

Total ammonia nitrogen in a volume of sludge in an aeration tank is measured and compared to a target ammonia nitrogen setpoint to calculate an airflow target for adjusting the measured total ammonia nitrogen toward the target ammonia nitrogen setpoint. The airflow target may be an airflow rate or, for an SBR, an airflow duration, and airflow into the aeration tank is adjusted according to the airflow target. A target solids retention time setpoint is also calculated from information relating to the airflow target and the solids retention time is adjusted toward the target solids retention time setpoint. The waste activated sludge flow rate for the aeration tank may be adjusted to adjust the solids retention time for the aeration tank toward the target solids retention time setpoint.

Systems and methods are described for automatically adjusting the composition of a spray chamber matrix gas flow coordinated with an analysis of a particular chemical element or groups of elements. A system can include a spray chamber configured to be coupled to an analytical system, the spray chamber having a nebulizer gas port configured to receive a nebulizer gas; and an inlet for receiving a gas from at least one gas source. The system also includes a controller operably coupled to the spray chamber, the controller configured to adjust a gas flow rate of the gas from the at least one gas source in coordination with analysis of a particular chemical element by the analytical system.

A control system for controlling the storage of metabolically active produce in a defined confined environment. The control system comprises gas analyzing and pressure measurement means including a control unit for determining an adjusted gas medium composition of the confined environment for protecting the produce against metabolic degradation. An operating/actuating means for adapting the gas medium in the confined storage environment is based on the determined adjusted gas medium composition. The control unit is adapted for determining the adjusted gas medium composition based on a mathematical model of the system that determines a metabolic coefficient of the produce by combining measured changes of gas composition in the confined environment with dynamic pressure changes in the confined space. The value of the metabolic coefficient is used as input for a control algorithm to continuously adjust the gas composition in the confined space in response to the metabolic activity of the produce.

The present invention relates to a method of controlling a concentration of a first component of a rectification column for separating a binary mixture of the first component with a second component on the basis of temperature measurements, wherein a control path defined by temperature sensors (T3, T2, T6) arranged in the longitudinal direction of the column is linearized with the aid of an estimated temperature profile, wherein a real temperature profile T*(h), determined by means of the temperature sensors, is approximated by a function T(h) in dependence on a column height h, wherein the column id divided into two sections along the column height h and the function T(h) is defined section by section on the basis, in each case, of a logistical function.

A materials processing furnace provides for debinding and sintering objects and treating effluent generated by the sintering. A heating chamber maintains a controlled atmosphere for sintering the object. A vacuum pump evacuates an effluent from the heating chamber, and an injector adds a reagent to the evacuated effluent to form a mixed gas. A catalytic converter receives the mixed gas and catalyzes one or more hazardous or offensive compounds of the effluent, thereby converting the effluent to a safer and less offensive exhaust. As a result, the furnace is suitable for operation in an office environment.