Abstract: According to examples, an apparatus may include an agent delivery device to deliver a coalescing agent to selected locations of a build material layer and a plurality of microwave energy emitters, each of the microwave energy emitters including a tip to generate a focused microwave energy field onto a respective area near the tip, in which the tip is to be positioned to place a portion of the build material layer within the focused microwave energy field. The apparatus may also include a controller that may control the microwave energy emitters to direct microwave energy onto the build material layer.

Abstract: In one example in accordance with the present disclosure, a system is described. The system includes at least one directional antenna to 1) emit energy waves towards a mass in which an object is disposed and 2) receive reflected signals from a resonator disposed on the object as the mass is moved relative to the directional antenna. The system also includes a controller to, based on received reflected signals, determine a pose of the object within the mass.

Abstract: In example implementations, a powder level sensor is provided. The powder level sensor includes a capacitive sensor, a processor, and a cleaning mechanism. The processor is communicatively coupled to the capacitive sensor. The processor interprets a measurement of the capacitive sensor to detect a layer of residual build material on a surface of the powder level sensor. The cleaning mechanism may be communicatively coupled to the processor. The processor activates the cleaning mechanism to remove the layer of residual build material on the surface of the powder level sensor.

Abstract: A 3D printer is disclosed herein. The 3D printer comprises a build material distributor to generate layers of a build material in a spreading direction along a spreading axis; a resonator mounted on the build material distributor to vibrate the build material distributor along the spreading axis at a frequency; and a controller. The controller is to control the resonator to vibrate the build material distributor at the frequency while controlling the build material distributor to spread a volume of build material over a platform to generate a layer of build material.

Abstract: A system and method for additive manufacturing (AM) including forming a product via AM, placing a resonator adjacent the product as the product is being formed in the AM, and determining a property of the product. The resonator operates over a microwave frequency spectrum and emanates electromagnetic energy.

Abstract: In an example of a method for three-dimensional (3D) printing, a polymeric or polymeric composite build material is applied. A dielectric agent is selectively applied on at least a portion of the polymeric or polymeric composite build material. The dielectric agent includes a dielectric material having an effective relative permittivity (?r) value ranging from 1.1 to about 10,000. A fusing agent is selectively applied on the at least the portion of the polymeric or polymeric composite build material, and the polymeric or polymeric composite build material is exposed to radiation to fuse the at least the portion of the polymeric or polymeric composite build material to form a region of a layer of a 3D part. The region exhibits a dielectric property, a piezoelectric property, or a combination thereof.

Abstract: In one example in accordance with the present disclosure, a system is described. The system includes at least one directional antenna to 1) emit energy waves towards a mass in which an object is disposed and 2) receive reflected signals from a resonator disposed on the object as the mass is moved relative to the directional antenna. The system also includes a controller to, based on received reflected signals, determine a pose of the object within the mass.

Abstract: In one example in accordance with the present disclosure, a system is described. The system includes a movement device to move a mass with an object disposed therein. A receiver of the system receives accelerometer data from at least one accelerometer disposed within the mass in which the object is disposed. A controller of the system determines a pose of the object within the mass based on received accelerometer data.

Abstract: In example implementations, a powder level sensor is provided. The powder level sensor includes a capacitive sensor, a processor, and a cleaning mechanism. The processor is communicatively coupled to the capacitive sensor. The processor interprets a measurement of the capacitive sensor to detect a layer of residual build material on a surface of the powder level sensor. The cleaning mechanism may be communicatively coupled to the processor. The processor activates the cleaning mechanism to remove the layer of residual build material on the surface of the powder level sensor.

Abstract: An example three-dimensional printing system receives a sensor response indicating a density of build material at positions of a layer of build material on a build platform. The three-dimensional printing system determines, based on the sensor response, an amount of energy to apply to the positions and instructs an energy source to apply the determined amount of energy to the positions.

Abstract: In an example of a method for three-dimensional (3D) printing, a polymeric or polymeric composite build material is applied. A dielectric agent is selectively applied on at least a portion of the polymeric or polymeric composite build material. The dielectric agent includes a dielectric material having an effective relative permittivity (?r) value ranging from 1.1 to about 10,000. A fusing agent is selectively applied on the at least the portion of the polymeric or polymeric composite build material, and the polymeric or polymeric composite build material is exposed to radiation to fuse the at least the portion of the polymeric or polymeric composite build material to form a region of a layer of a 3D part. The region exhibits a dielectric property, a piezoelectric property, or a combination thereof.

Abstract: According to examples, an apparatus may include an agent delivery device to deliver a coalescing agent to a selected location of a build material layer and a plurality of microwave energy emitters, each of which may include a tip to generate a focused microwave energy field onto a respective area near the tip. The apparatus may also include a controller that may control delivery of a first signal to a first microwave energy emitter of the plurality of microwave energy emitters; receive an energy feedback signal corresponding to energy reflected back into the first microwave energy emitter; determine, based on the received energy feedback signal, a power level of a second signal to be delivered to a microwave energy emitter of the plurality of microwave energy emitters; and control delivery of the second signal at the determined power level to the microwave energy emitter.

Abstract: According to examples, an apparatus may include an agent delivery device to deliver a coalescing agent to selected locations of a build material layer and a plurality of microwave energy emitters, each of the microwave energy emitters including a tip to generate a focused microwave energy field onto a respective area near the tip, in which the tip is to be positioned to place a portion of the build material layer within the focused microwave energy field. The apparatus may also include a controller that may control the microwave energy emitters to direct microwave energy onto the build material layer.

Abstract: A system and method for additive manufacturing (AM) including forming a product via AM, placing a resonator adjacent the product as the product is being formed in the AM, and determining a property of the product. The resonator operates over a microwave frequency spectrum and emanates electromagnetic energy.

Abstract: A three-dimensional (3D) object printing kit includes a polymeric material; a fusing agent including at least 5 vol % of a polar solvent; and a detailing agent. The detailing agent includes a non-polar, hydrophobic substance selected from the group consisting of a non-polar, hydrophobic liquid in its liquid state at a temperature ranging from about ?80° C. to about 40° C., and a non-polar, hydrophobic wax having a melting temperature less than 120° C.

Abstract: In an example, an apparatus includes processing circuitry comprising a model assessment module to identify an indication of a conductive element within object model data representing an object to be printed and a print instruction module to generate print instructions to generate the object. The print instructions may include an instruction to print conductive agent to form the conductive element and an instruction to print a fusing agent comprising an instruction to reduce an amount of fusing agent to be printed in a region of the conductive element compared to at least one other region of the object.

Abstract: A MW signal is delivered to a waveguide with a coaxial concentrator. At least one of an amplitude and a phase of a reflected signal from the coaxial concentrator is monitored to determine material characteristics of a build material fusion process.

Abstract: Examples disclosed herein relate to a layered RFID tag. In one implementation, a layered passive chipless RFID tag includes a first conductive layer, a second dielectric layer, and a third conductive layer. The first, second, and third layers may be in a stacked configuration with the second layer between the first layer and the second layer.

Abstract: A method of indexing a data stream is disclosed. The method includes initiating the data stream in the video conference, recording the data stream, indexing the data stream by generating a transcript of the recorded data stream, linking the transcript with a video portion of the data stream and storing the indexed data stream onto a data storage medium.

Abstract: A method of sending video data over a network is disclosed. The method includes initiating a video data stream between a first site and a second site over the network, sending compressed video content from the first site to the second site, decompressing the video content at the first site, decompressing the video content at the second site and synchronizing the decompressed video content at the first and second site whereby the video data stream can be controlled by either the first or second site.