scholarly journals In situ measurement of micro flow rate using near infrared absorption method

2018 ◽  
Vol 26 (13) ◽  
pp. 17078 ◽  
Author(s):  
Seok Hwan Lee ◽  
Joohyun Lee ◽  
Sejong Chun ◽  
Woong Kang
Keyword(s):  
Flow Rate ◽  
Infrared Absorption ◽  
Near Infrared ◽  
In Situ Measurement ◽  
Absorption Method ◽  
Micro Flow

scholarly journals In situ measurement and closed-loop control for powder supply processes

2021 ◽  
Author(s):  
Philipp Peter Breese ◽  
Tobias Hauser ◽  
Daniel Regulin ◽  
Stefan Seebauer ◽  
Christian Rupprecht
Keyword(s):  
Mass Flow Rate ◽  
Mass Flow ◽  
Flow Rate ◽  
Closed Loop ◽  
In Situ Measurement ◽  
Closed Loop Control ◽  
Loop Control ◽  
Powder Feeder ◽  
Powder Mass

AbstractThe powder mass flow rate is one of the main parameters regarding the geometrical precision of built components in the additive manufacturing process of laser metal deposition. However, its accuracy, constancy, and repeatability over the course of the running process is not given. Reasons among others are the performance of the powder conveyors, the complex nature of the powder behavior, and the resulting issues with existing closed-loop control approaches. Additionally, a direct in situ measurement of the powder mass flow rate is only possible with intrusive methods. This publication introduces a novel approach to measure the current powder mass flow rate at a frequency of 125 Hz. The volumetric powder flow evaluation given by a simple optical sensor concept was transferred to a mass flow rate through mathematical dependencies. They were found experimentally for a nickel-based powder (Inconel 625) and are valid for a wide range of mass flow rates. With this, the dynamic behavior of a vibration powder feeder was investigated and a memory effect dependent on previous powder feeder speeds was discovered. Next, a closed-loop control with the received sensor signal was implemented. The concept as a whole gives a repeatable and accurate powder mass flow rate while being universally retrofittable and applicable. In a final step, the improved dynamic and steady performance of the powder mass flow rate with closed-loop control was validated. It showed a reduction of mean relative errors for step responses of up to 81% compared to the uncontrolled cases.

scholarly journals Near infrared laser annealing of CdTe and in-situ measurement of the evolution of structural and optical properties

2016 ◽  
Vol 119 (16) ◽  
pp. 165305 ◽  
Author(s):  
Brian J. Simonds ◽  
Sudhajit Misra ◽  
Naba Paudel ◽  
Koen Vandewal ◽  
Alberto Salleo ◽  
...  
Keyword(s):  
Optical Properties ◽  
Near Infrared ◽  
Laser Annealing ◽  
Infrared Laser ◽  
In Situ Measurement ◽  
Structural And Optical Properties

In situ measurement of temperature dependent picosecond resolved carrier dynamics in near infrared (NIR) sensitive device on action

2019 ◽  
Vol 90 (4) ◽  
pp. 043909 ◽  
Author(s):  
Jayita Patwari ◽  
Arka Chatterjee ◽  
Hemant Ghadi ◽  
Hemant Sharma ◽  
Subhananda Chakrabarti ◽  
...  
Keyword(s):  
Near Infrared ◽  
Carrier Dynamics ◽  
In Situ Measurement ◽  
Temperature Dependent

In situ measurement of the infrared absorption and extinction of chemical and biologically derived aerosols using flow-through photoacoustics

2005 ◽  
Vol 44 (19) ◽  
pp. 4096 ◽  
Author(s):  
Kristan P. Gurton ◽  
Rachid Dahmani ◽  
David Ligon ◽  
Burt V. Bronk
Keyword(s):  
Infrared Absorption ◽  
In Situ Measurement ◽  
Flow Through

Discussion of Problems of Measurement Carbon on the Inner Surface of Inner Grooved Copper Tube by Infrared Absorption Method

2012 ◽  
Vol 503-504 ◽  
pp. 1347-1350
Author(s):  
Huai Bao Yuan ◽  
Yue Hong Li
Keyword(s):  
Flow Rate ◽  
Infrared Absorption ◽  
Copper Tube ◽  
Absorption Method ◽  
Calibration Constant ◽  
Integral Calculus ◽  
Surface Carbon ◽  
Inner Surface ◽  
Recovery Experiment

The inner surface carbon in the inner grooved copper tube was determined by tube furnace heating-infrared absorption method. Some factors which influenced the determination such as sample preparation and cleaning, flow rate, furnace constants, blank value, calibration constant were tested and optimized. The inner surface carbon of copper tube was released completely while the experiment temperature was chosen as 400~600°C and the flow rate of oxygen was 750 mL/min. And the obtained integral calculus curve was ideal. The method has been applied to the determination of inner surface carbon in the inner grooved copper tube with carbon content of 0.24 mg/dm2. The result of the RSD was 3.7％. And the recovery experiment through joining in synthesize carbon sample was carried on, the recovery was 98～103%.

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