Provided herein are systems, apparatuses, and methods for localized, on-demand diesel exhaust fluid (DEF) production. The systems can comprise a loading station for securing a container comprising a pre-measured quantity of urea and releasing the urea from the container. The released urea and water can then be fed into a mixing tank to produce the DEF product. The water can be pre-treated, for example, in a reverse osmosis and/or deionization process before being fed to the mixing tank. The DEF product can be immediately dispensed into a diesel vehicle or stored in a nearby intermediate storage tank. The systems and processes advantageously reduce or eliminate the need for over-the-road shipments and retail packaging of DEF.

A solution management system (1) for bioprocessing, wherein each flow path formed between solution inlets (2) and solution outlets (9) of the system comprises one or more bend sections having an inner cross-sectional area and/or an inner cross-sectional geometry and/or a centre line radius varying along the length of the bend section. Various embodiments of the solution management system (1) provide for improved laminar fluid flow with a reduced pressure drop between the solution inlets (2) and solution outlets (9) therein.

This application provides a pool robot and an automatic underwater spreading method. The pool robot includes a body, a storage module configured to store a to-be-spread reagent, where the storage module is disposed on the body, and a first opening is disposed on the storage module a drive module disposed on the body, connected to the storage module, and configured to drive and control the reagent in the storage module to be spread through the first opening, a moving module disposed on the body and configured to drive the pool robot to move in water along a motion path, and a control module disposed on the body connected to the moving module via signals, and configured to control the moving module to move.

Disclosed are a solution preparation device, a solution replacement system and a solution replacement method. The solution preparation device comprises a liquid container, a powder container, an upper cover and a controller; the liquid container is provided with a detection element for detecting a specific parameter of a solution; the powder container is arranged above the liquid container, and the upper cover covers a top end of the powder container to form a material holding cavity for placing a powder, a bottom end of the powder container is provided with a material discharge port through which the powder in the material holding cavity enters the liquid container. The solution preparation device further comprises a stopper for blocking the material discharge port, the controller controls the stopper according to the specific parameter to realize opening and closing of the material discharge port.