Predictive Modeling of Droplet Velocity and Size in Inkjet-Based Bioprinting

2018 ◽  
Author(s):  
Dazhong Wu ◽  
Changxue Xu ◽  
Srikumar Krishnamoorthy
Keyword(s):  
Droplet Size ◽  
Predictive Models ◽  
Formation Process ◽  
Imaging System ◽  
Droplet Formation ◽  
Droplet Velocity ◽  
Data Driven Approach ◽  
Factorial Design Of Experiments ◽  
Living Tissues ◽  
And Control

Additive manufacturing is driving major innovations in many areas such as biomedical engineering. Recent advances have enabled 3D printing of biocompatible materials and cells into complex 3D functional living tissues and organs using bioink. Inkjet-based bioprinting fabricates the tissue and organ constructs by ejecting droplets onto a substrate. Compared with microextrusion-based and laser-assisted bioprinting, it is very difficult to predict and control the droplet formation process (e.g., droplet velocity and size). To address this issue, this paper presents a new data-driven approach to predict droplet velocity and size in the inkjet-based bioprinting process. An imaging system was used to monitor the droplet formation process. To investigate the effects of excitation voltage, dwell time, and rise time on droplet velocity and droplet size, a full factorial design of experiments was conducted. Two predictive models were developed to predict droplet velocity and droplet size using random forests. The accuracy of the two predictive models was evaluated using the relative error. Experimental results have shown that the predictive models are capable of predicting droplet velocity and size with sufficient accuracy.

Predictive Modeling of Droplet Formation Processes in Inkjet-Based Bioprinting

2018 ◽  
Vol 140 (10) ◽  
Author(s):  
Dazhong Wu ◽  
Changxue Xu
Keyword(s):  
Predictive Models ◽  
Formation Process ◽  
Imaging System ◽  
Polymer Concentration ◽  
Three Dimensional ◽  
Droplet Formation ◽  
Droplet Velocity ◽  
Coefficient Of Determination ◽  
Data Driven Approach ◽  
Living Tissues

Additive manufacturing is driving major innovations in many areas such as biomedical engineering. Recent advances have enabled three-dimensional (3D) printing of biocompatible materials and cells into complex 3D functional living tissues and organs using bio-printable materials (i.e., bioink). Inkjet-based bioprinting fabricates the tissue and organ constructs by ejecting droplets onto a substrate. Compared with microextrusion-based and laser-assisted bioprinting, it is very difficult to predict and control the droplet formation process (e.g., droplet velocity and volume). To address this issue, this paper presents a new data-driven approach to predicting droplet velocity and volume in the inkjet-based bioprinting process. An imaging system was used to monitor the droplet formation process. To investigate the effects of polymer concentration, excitation voltage, dwell time, and rise time on droplet velocity and volume, a full factorial design of experiments (DOE) was conducted. Two predictive models were developed to predict droplet velocity and volume using ensemble learning. The accuracy of the two predictive models was measured using the root-mean-square error (RMSE), relative error (RE), and coefficient of determination (R2). Experimental results have shown that the predictive models are capable of predicting droplet velocity and volume with sufficient accuracy.

scholarly journals Parametric Study of Jet/Droplet Formation Process during LIFT Printing of Living Cell-Laden Bioink

Micromachines ◽  
2021 ◽  
Vol 12 (11) ◽  
pp. 1408
Author(s):  
Christina Kryou ◽  
Ioannis Theodorakos ◽  
Panagiotis Karakaidos ◽  
Apostolos Klinakis ◽  
Antonios Hatziapostolou ◽  
...  
Keyword(s):  
Formation Process ◽  
Imaging System ◽  
Three Dimensional ◽  
Droplet Formation ◽  
Layer By Layer ◽  
Time Resolved ◽  
Wide Range ◽  
Cell Concentrations ◽  
Living Tissues ◽  
Uniform Droplets

Bioprinting offers great potential for the fabrication of three-dimensional living tissues by the precise layer-by-layer printing of biological materials, including living cells and cell-laden hydrogels. The laser-induced forward transfer (LIFT) of cell-laden bioinks is one of the most promising laser-printing technologies enabling biofabrication. However, for it to be a viable bioprinting technology, bioink printability must be carefully examined. In this study, we used a time-resolved imaging system to study the cell-laden bioink droplet formation process in terms of the droplet size, velocity, and traveling distance. For this purpose, the bioinks were prepared using breast cancer cells with different cell concentrations to evaluate the effect of the cell concentration on the droplet formation process and the survival of the cells after printing. These bioinks were compared with cell-free bioinks under the same printing conditions to understand the effect of the particle physical properties on the droplet formation procedure. The morphology of the printed droplets indicated that it is possible to print uniform droplets for a wide range of cell concentrations. Overall, it is concluded that the laser fluence and the distance of the donor–receiver substrates play an important role in the printing impingement type; consequently, a careful adjustment of these parameters can lead to high-quality printing.

Investigation of Temperature-Dependent Droplet Formation of Nanofluids in Microfluidic T-Junction

2008 ◽  
Author(s):  
Nam-Trung Nguyen ◽  
S. M. Sohel Murshed ◽  
Say-Hwa Tan
Keyword(s):  
Droplet Size ◽  
Formation Process ◽  
Size Control ◽  
Droplet Formation ◽  
Deionized Water ◽  
Experimental Investigations ◽  
Temperature Dependent ◽  
Potential Applications ◽  
Increasing Temperature ◽  
Different Characteristics

The study on the control of microdroplet formation and manipulation is very important due to the potential applications of droplet-based microfluidics in various important fields. Experimental investigations on thermally controlled droplet formation and size manipulation of deionized water and nanofluids in a microfluidic T-junction are reported in this paper. The heater temperature affects the droplet formation process. Nanofluids are found to exhibit different characteristics in droplet formation and size control with the temperature. Addition of spherical-shaped TiO2 (15 nm) nanoparticles in deionized water results in much smaller droplet size compared to the cylindrical-shaped TiO2 (10×40) nm) nanoparticles. Other than nanofluid with cylindrical-shaped nanoparticles, the droplet size was found to increase with increasing temperature.

Advanced Fringe Analysis Techniques in Circuit Edit

2006 ◽  
Author(s):  
R.K. Jain ◽  
T. Malik ◽  
T.R. Lundquist ◽  
C.-C. Tsao ◽  
W.J. Walecki
Keyword(s):  
Imaging System ◽  
Success Rates ◽  
Endpoint Detection ◽  
Fringe Analysis ◽  
Analysis Techniques ◽  
Aspect Ratios ◽  
Slope Correction ◽  
Trench Area ◽  
And Control ◽  
Thickness Measurements

Abstract Novel Fabry Perot [1] fringe analysis techniques for monitoring the etching process with a coaxial photon-ion column [2] in the Credence OptiFIB are reported. Presently the primary application of these techniques in circuit edit is in trenching either from the front side or from the backside of a device. Optical fringes are observed in reflection geometry through the imaging system when the trench floor is thin and semi-transparent. The observed fringes result from optical interference in the etalon formed between the trench floor (Si in the case of backside trenching) and the circuitry layer beyond the trench floor. In-situ real-time thickness measurements and slope correction techniques are proposed that improve endpoint detection and control planarity of the trench floor. For successful through silicon edits, reliable endpoint detection and co-planarity of a local trench is important. Reliable endpoint detection prevents milling through bulk silicon and damaging active circuitry. Uneven trench floor thickness results in premature endpoint detection with sufficient thickness remaining in only part of the trench area. Good co-planarity of the trench floor also minimizes variability in the aspect ratios of the edit holes, hence increasing success rates in circuit edit.

scholarly journals Real-Time In Vivo Bioluminescent Imaging for Evaluating the Efficacy of Antibiotics in a Rat Staphylococcus aureus Endocarditis Model

2005 ◽  
Vol 49 (1) ◽  
pp. 380-387 ◽  
Author(s):  
Yan Q. Xiong ◽  
Julie Willard ◽  
Jagath L. Kadurugamuwa ◽  
Jun Yu ◽  
Kevin P. Francis ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Real Time ◽  
Imaging System ◽  
Bioluminescent Imaging ◽  
Vancomycin Therapy ◽  
Treatment Groups ◽  
Highly Sensitive ◽  
Relevant Animal Model ◽  
And Control

ABSTRACT Therapeutic options for invasive Staphylococcus aureus infections have become limited due to rising antimicrobial resistance, making relevant animal model testing of new candidate agents more crucial than ever. In the present studies, a rat model of aortic infective endocarditis (IE) caused by a bioluminescently engineered, biofilm-positive S. aureus strain was used to evaluate real-time antibiotic efficacy directly. This strain was vancomycin and cefazolin susceptible but gentamicin resistant. Bioluminescence was detected and quantified daily in antibiotic-treated and control animals with IE, using a highly sensitive in vivo imaging system (IVIS). Persistent and increasing cardiac bioluminescent signals (BLS) were observed in untreated animals. Three days of vancomycin therapy caused significant reductions in both cardiac BLS (>10-fold versus control) and S. aureus densities in cardiac vegetations (P < 0.005 versus control). However, 3 days after discontinuation of vancomycin therapy, a greater than threefold increase in cardiac BLS was observed, indicating relapsing IE (which was confirmed by quantitative culture). Cefazolin resulted in modest decreases in cardiac BLS and bacterial densities. These microbiologic and cardiac BLS differences during therapy correlated with a longer time-above-MIC for vancomycin (>12 h) than for cefazolin (∼4 h). Gentamicin caused neither a reduction in cardiac S. aureus densities nor a reduction in BLS. There were significant correlations between cardiac BLS and S. aureus densities in vegetations in all treatment groups. These data suggest that bioluminescent imaging provides a substantial advance in the real-time monitoring of the efficacy of therapy of invasive S. aureus infections in live animals.

scholarly journals A LabVIEW Platform for Preclinical Imaging Using Digital Subtraction Angiography and Micro-CT

2013 ◽  
Vol 2013 ◽  
pp. 1-13 ◽  
Author(s):  
Cristian T. Badea ◽  
Laurence W. Hedlund ◽  
G. Allan Johnson
Keyword(s):  
Digital Subtraction Angiography ◽  
Functional Imaging ◽  
Imaging System ◽  
Micro Ct ◽  
Digital Subtraction ◽  
X Ray ◽  
Retrospective Gating ◽  
Dual Source ◽  
Labview Platform ◽  
And Control

CT and digital subtraction angiography (DSA) are ubiquitous in the clinic. Their preclinical equivalents are valuable imaging methods for studying disease models and treatment. We have developed a dual source/detector X-ray imaging system that we have used for both micro-CT and DSA studies in rodents. The control of such a complex imaging system requires substantial software development for which we use the graphical language LabVIEW (National Instruments, Austin, TX, USA). This paper focuses on a LabVIEW platform that we have developed to enable anatomical and functional imaging with micro-CT and DSA. Our LabVIEW applications integrate and control all the elements of our system including a dual source/detector X-ray system, a mechanical ventilator, a physiological monitor, and a power microinjector for the vascular delivery of X-ray contrast agents. Various applications allow cardiac- and respiratory-gated acquisitions for both DSA and micro-CT studies. Our results illustrate the application of DSA for cardiopulmonary studies and vascular imaging of the liver and coronary arteries. We also show how DSA can be used for functional imaging of the kidney. Finally, the power of 4D micro-CT imaging using both prospective and retrospective gating is shown for cardiac imaging.

Numerical Simulation and Experiment of Atomization Field of Fan-Shaped Atomization Nozzle for Plant Protection UAV

2021 ◽  
Vol 14 ◽  
Author(s):  
Maohua Xiao ◽  
Yuanfang Zhao ◽  
Zhenmin Sun ◽  
Chaohui Liu ◽  
Tianpeng Zhang
Keyword(s):  
Numerical Simulation ◽  
Size Distribution ◽  
Droplet Size ◽  
Plant Protection ◽  
Cone Angle ◽  
Droplet Size Distribution ◽  
Droplet Velocity ◽  
Inlet Pressure ◽  
Spray Cone Angle ◽  
Spray Cone

Background: There are drift and volatilization of the droplets produced by the plant protection Unmanned Aerial Vehicle (UAV) under the influence of external wind speed and its flight speed. Objective: It studied the atomization characteristics of its fan-shaped atomizing nozzle under different inlet pressures and inner cavity diameters. Methods: For the start, the Realizable k-ε turbulence model, DPM discrete phase model and TAB breakup model are used to make a numerical simulation of the spray process of the nozzle. Then, the SIMPLE algorithm is used to obtain the droplet size distribution diagram of the nozzle atomization field. At last, the related test methods are used to study its atomization performance, and the changes of atomization angle and droplet velocity under different inlet pressures and inner cavity diameters and the distribution of droplet size are discussed. Results: The research results show that under the same inner cavity diameter, as the inlet pressure increases, the spray cone angle of the nozzle and the droplet velocity at the same distance from the nozzle increase. As the distance from the nozzle increases, the droplet velocity decreases gradually, the droplet size distribution moves to the direction of small diameter, and the droplets in the anti-drift droplet size area increase. Under the same inlet pressure, as the diameter of the inner cavity increases, the spray cone angle first increases and then decreases, and the droplet velocity at the same distance from the nozzle increases. As the distance from the nozzle increases, the droplet velocity decreases gradually, the droplet size distribution moves to the direction of large diameter, and the large size droplets increase, which cannot meet the anti-drift volatilization effect. Conclusion: Under the parameter set in this study, when the inlet pressure is 0.6MPa and the inner cavity diameter is 2mm, the atomization result is the best.

scholarly journals Line of Sight and Image Motion Compensation for Step and Stare Imaging System

2020 ◽  
Vol 10 (20) ◽  
pp. 7119
Author(s):  
Jihong Xiu ◽  
Pu Huang ◽  
Jun Li ◽  
Hongwen Zhang ◽  
Youyi Li
Keyword(s):  
High Resolution ◽  
Motion Compensation ◽  
Imaging System ◽  
Control Flow ◽  
Image Motion ◽  
Line Of Sight ◽  
Pointing Accuracy ◽  
High Resolution Images ◽  
Pointing Control ◽  
And Control

In recent years, applications such as marine search and rescue, border patrol, etc. require electro-optical equipment to have both high resolution and precise geographic positioning abilities. The step and stare working based on a composite control system is a preferred solution. This paper proposed a step and stare system composed of two single-axis fast steering mirrors and a two-axis gimbal. The fast steering mirrors (FSMs) realize image motion compensation and the gimbal completes pointing control. The working principle and the working mode of the system are described first. According to the imaging optical path, the algorithm and control flow of the line of sight (LOS) and image motion compensation are developed. The proposed method is verified through ground imaging and flight tests. Under the condition of flight, the pointing accuracy of the target can be controlled within 15 m. The proposed algorithm can achieve effective motion compensation and get high-resolution images. This achieves high resolution and accurate LOS simultaneously.

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