Abstract: According to an example, an apparatus may include a memory that may store instructions to cause a processor to generate, for each part to be fabricated in a build envelope of a 3D fabricating device, first level descriptions and second level descriptions for the part. The processor may determine, using the first level descriptions, whether there is an arrangement that results in the parts jointly fitting within the build envelope while providing certain thermal decoupling spaces between the parts. In response to a determination that the arrangement using the first level descriptions for the parts has not been determined, the processor may determine, using the second level descriptions, whether there is an arrangement that results in the parts jointly fitting within the build envelope while providing the certain thermal decoupling spaces.

Abstract: An example device includes a first droplet ejector including a first nozzle to eject droplets of a first fluid, and a first target medium positioned relative to the first droplet ejector to receive the droplets of the first fluid from the first droplet ejector. The example device further includes a second droplet ejector in fluid communication with the first target medium to receive a second fluid from the first target medium. The second droplet ejector includes a second nozzle to eject droplets of the second fluid.

Abstract: In some examples, data representing a three-dimensional object is received. The data may comprise an object property description associated with each of a plurality of locations within the object. At least one object generation parameter description associated with a region of the object may be determined from the data. The object generation parameter description may comprise at least one object generation apparatus control parameter value and a probability that control data generated therefrom will specify said object generation apparatus control parameter value for generating the region of the object.

Abstract: An example device includes a first droplet ejector including a first nozzle to eject droplets of a first fluid, and a first target medium positioned relative to the first droplet ejector to receive the droplets of the first fluid from the first droplet ejector. The example device further includes a second droplet ejector in fluid communication with the first target medium to receive a second fluid from the first target medium. The second droplet ejector includes a second nozzle to eject droplets of the second fluid.

Abstract: According to an example, a three-dimensional (3D) printer may include a first delivery device to selectively deposit a fusing agent onto a layer of build materials and a second delivery device to deposit coolant droplets at tuned drop weights onto the layer of build materials. The 3D printer may also include a controller to control the second delivery device to selectively deposit the coolant droplets at the tuned drop weights onto selected areas of the build material layer, in which the drop weights of the selectively deposited coolant droplets are tuned to provide a thermal balance between multiple areas of the build material layer during application of fusing radiation onto the build material layer.

Abstract: According to an example, a three-dimensional (3D) printer may include a first delivery device to selectively deposit first liquid droplets onto a layer of build materials, in which the first liquid has a fusing radiation absorption property. The 3D printer may also include a fusing radiation generator to selectively emit fusing radiation at multiple ranges of wavelengths and at selected locations to selectively fuse the build materials and a controller to tune a range of wavelengths at which the fusing radiation generator is to emit fusing radiation based upon the fusing radiation absorbing property of the deposited first liquid, to determine the selected locations at which the fusing radiation at the tuned range of wavelengths is to be emitted, and to control the fusing radiation generator to selectively emit fusing radiation at the tuned range of wavelengths and onto the selected locations.

Abstract: The present disclosure is drawn to a particulate build material for three-dimensional printing. The particulate build material can include a plurality of particulates, wherein individual particulates include a particulate core having a photosensitive coating applied to a surface of the particulate core. The particulate core includes a metal, a ceramic, or both a metal and a ceramic. The photosensitive coating includes a polymer having a photosensitive agent suspended or attached therein.

Abstract: According to an example, an apparatus may include a memory that may store instructions to cause a processor to generate, for each part to be fabricated in a build envelope of a 3D fabricating device, first level descriptions and second level descriptions for the part. The processor may determine, using the first level descriptions, whether there is an arrangement that results in the parts jointly fitting within the build envelope while providing certain thermal decoupling spaces between the parts. In response to a determination that the arrangement using the first level descriptions for the parts has not been determined, the processor may determine, using the second level descriptions, whether there is an arrangement that results in the parts jointly fitting within the build envelope while providing the certain thermal decoupling spaces.

Abstract: A sample comprising a first substance and a second substance is modified by breaking down molecular bonds of the second substance of the sample to form a modified sample having altered surface enhanced luminescence (SEL) characteristics to reduce overlapping of SEL characteristics of the first substance in the second substance. Surface enhanced luminescence data resulting from excitation of the modified sample is collected. Characteristics of the first substance based upon the collected surface enhanced luminescence data are identified.

Abstract: The present disclosure is drawn to a particulate build material for three-dimensional printing. The particulate build material can include a plurality of particulates, wherein individual particulates include a particulate core having a photosensitive coating applied to a surface of the particulate core. The particulate core includes a metal, a ceramic, or both a metal and a ceramic. The photosensitive coating includes a polymer having a photosensitive agent suspended or attached therein.

Abstract: According to an example, a three-dimensional (3D) printer may include a first delivery device to selectively deposit first liquid droplets onto a layer of build materials, in which the first liquid has a fusing radiation absorption property. The 3D printer may also include a fusing radiation generator to selectively emit fusing radiation at multiple ranges of wavelengths and at selected locations to selectively fuse the build materials and a controller to tune a range of wavelengths at which the fusing radiation generator is to emit fusing radiation based upon the fusing radiation absorbing property of the deposited first liquid, to determine the selected locations at which the fusing radiation at the tuned range of wavelengths is to be emitted, and to control the fusing radiation generator to selectively emit fusing radiation at the tuned range of wavelengths and onto the selected locations.

Abstract: According to an example, a three-dimensional (3D) printer may include a first delivery device to selectively deposit a fusing agent onto a layer of build materials and a second delivery device to deposit coolant droplets at tuned drop weights onto the layer of build materials. The 3D printer may also include a controller to control the second delivery device to selectively deposit the coolant droplets at the tuned drop weights onto selected areas of the build material layer, in which the drop weights of the selectively deposited coolant droplets are tuned to provide a thermal balance between multiple areas of the build material layer during application of fusing radiation onto the build material layer.

Abstract: In some examples, data representing a three-dimensional object is received. The data may comprise an object property description associated with each of a plurality of locations within the object. At least one object generation parameter description associated with a region of the object may be determined from the data. The object generation parameter description may comprise at least one object generation apparatus control parameter value and a probability that control data generated therefrom will specify said object generation apparatus control parameter value for generating the region of the object.

Abstract: A fluid ejection device includes a fluid recirculation channel, and a drop generator disposed within the channel. A fluid slot is in fluid communication with each end of the channel, and a piezoelectric fluid actuator is located asymmetrically within the recirculation channel to cause fluid flow from the fluid slot, through the recirculation channel and drop generator, and back to the fluid slot.

Abstract: A fluid ejection device includes a fluid recirculation channel, and a drop generator disposed within the channel. A fluid slot is in fluid communication with each end of the channel, and a piezoelectric fluid actuator is located asymmetrically within the recirculation channel to cause fluid flow from the fluid slot, through the recirculation channel and drop generator, and back to the fluid slot.

Abstract: A solar radiation collection system includes a first photovoltaic cell, a second photovoltaic cell, and an optical medium, the optical medium. The optical medium has a first zone configured to transmit radiation incident on the first zone to the first cell, a second zone disposed adjacent a side of the first zone, and a first dichroic surface configured to reflect a first portion of radiation incident on the second zone such that the reflected radiation is directed toward the first cell by internal reflection and to transmit a second portion of radiation incident on the second zone to the second cell.

Abstract: A print head laminate includes a flexible glass layer between an adhesive layer and an electrical conductor.

Abstract: A method is disclosed for creating an emitter having a flat cathode emission surface: First a protective layer that is conductive is formed on the flat cathode emission surface. Then an electronic lens structure is created over the protective layer. Finally, the protective layer is etched to expose the flat cathode emission surface.

Abstract: An emitter has an electron supply layer and a tunneling layer formed on the electron supply layer. Optionally, an insulator layer is formed on the electron supply layer and has openings defined within in which the tunneling layer is formed. A cathode layer is formed on the tunneling layer to provide a surface for energy emissions of electrons and/or photons. Preferably, the emitter is subjected to an annealing process thereby increasing the supply of electrons tunneled from the electron supply layer to the cathode layer.

Abstract: An electrical device includes a plurality of integrated circuits respectively fabricated in a first substrate bonded to a second substrate by a bond that deforms above, but not below, a deformation condition. The deformation condition can be a predetermined pressure from opposing surfaces on the first and second substrates or it can be a predetermined combination of temperature and pressure from opposing surfaces on the first and second substrates.