Browsing by Subject "droplet formation"

Now showing 1 - 3 of 3

3D Inkjetting Droplet Formation of Bacterial Cellulosic Exopolysaccharide Gel
(University of Texas at Austin, 2016) Aguiar, Daniel; Albuquerque, Amanda; Li, Bingbing
On-demand 3D printing of scaffolds and cell-laden structures has shown promising results that can significantly impact human welfare. The objective is to fully understand the behavior of bacterial cellulosic exopolysaccharide gel (BCEG) as a new bioink with low toxicity and high biocompatibility for regenerative medicine. Its possible application is to construct scaffolds that can be used for several biomedical applications, especially tissue engineering and treatment of critical bone defects. By using a MicroFab inkjet micro dispenser, BCEG was dispersed to create drops on demand that can be used to fabricate scaffolds. In order to fully understand the material’s behavior and droplet formation, we analyzed the physical and mechanical properties of the BCEG in different concentrations (0.1% 0.5% and 1%) and characterized it by its macroscopy, microscopy, rheology and particle size distribution.
Inkjet Printing at Megahertz Frequency
(University of Texas at Austin, 2015) Miers, John C.; Zhou, Wenchao
Inkjet printing enables more efficient, economic, scalable manufacturing for a wider variety of materials, than other traditional additive techniques. However, the jetting frequency of commercial droplet-on-demand inkjet techniques is mostly limited to ~10 kHz. This paper presents an investigation of the possibility of jetting at megahertz frequencies in order to boost the productivity of inkjet by ~100 times. The key to this problem is rooted in droplet formation dynamics, a subject that has been extensively studied for over 300 years. Hence, the focus of this paper is to understand the limitations of generating droplets at a megahertz frequency and explore possible solutions for overcoming these limitations. The paper begins with a review of literature on the dynamics of droplet formation. A numerical model is then developed for the simulation of droplet formation dynamics. The numerical model is validated against available experimental data from the literature. Aided by insights gained from scaling analysis, the validated model is then used to study the effects of different process parameters on high frequency jetting. The study finds energy density input to the nozzle is the key to achieve megahertz frequency printing.
Time-Resolved Study of Droplet Formation Process During Inkjetting of Alginate Solution
(University of Texas at Austin, 2013) Xu, Changxue; Zhang, Zhengyi; Fu, Jianzhong; Huang, Yong; Markwald, Roger R.
Organ printing offers a great potential for the fabrication of three-dimensional (3D) living organs by precisely layer-by-layer placing various tissue spheroids. Such fabricated organs may replace some damaged or injured human organs, emerging as a promising solution to the problem of organ donor shortage. As one of the key enabling technologies for organ printing, inkjetting has been received much attention recently. It is of great importance to understand the jetting and droplet formation processes during the inkjetting of typical biomaterials such as alginate solution. The jetting behavior and breakup time during alginate inkjetting have been studied using a time-resolved approach, and different pinch-off behaviors are classified. The resulting knowledge will help better promote the inkjetting-based organ printing technology.