Abstract: In one example, a depowdering system for an object printed with a powder based 3D printer includes a process selector and a depowdering unit operatively connected to the process selector. The process selector is programmed to access a set of object features, access a threshold precision and/or a threshold yield for depowdering, access a set of depowdering processes including precision and/or yield information for each depowdering process in the set, identify a feature in the set of object features in a model of the object, select a depowdering process from the set of depowdering processes based on the identified feature to achieve the threshold precision and/or the threshold yield, and cause the depowdering unit to perform the selected process on the object.

Abstract: In one example, a method for 3D printing includes identifying, in a model of an object, a feature of the object and automatically selecting a depowdering process for an object printed using the model based on the identified feature.

Abstract: The invention is an improved method for regenerating liquid streams which contain sulfur dioxide. The method comprises providing a body of liquid which contains sulfur dioxide having a free space above the surface; forming a mixture of gas bubbles in the liquid by admixing a sufficient amount of gas containing hydrogen sulfide with the liquid to react with the liquid to form sulfur and to provide a sufficient amount of gas bubbles to separate sulfur formed from the body of the liquid by flotation. The method is particularly useful for regenerating aqueous absorbents in cyclic processes for removing sulfur dioxide from gas streams.