Application of Axiomatic Design Theory to a Microfluidic Device for the Production of Uniform Water-in-Oil Microspheres Adapting an Integration Method

Author(s):  
Ki-Young Song ◽  
Wen-Jun Zhang ◽  
Madan M. Gupta

This work describes a novel microfluidic method to generate uniform water-in-oil (W/O) microspheres using the phase separation technique. Axiomatic design theory (ADT) was employed for the conceptual design of microchannel systems, and ADT verified that the proposed microfluidic system is a decoupled design. The integration of hydrodynamic flow focusing method and crossflow method is realized in a microfluidic device with oil phase and aqueous phase. The immiscible fluids are fed by continuous air pressure. By the hydrodynamic flow focusing method, the width of the dispersed focused aqueous phase is controlled. The focused flow enters T-junction geometry downstream, and the crossflow interferes with the focused flow. By varying the applied pressure to the crossflow, the W/O microspheres are formed at the T-junction. Based on this approach, the size of the W/O microspheres can be successfully controlled from 16 μm to 35 μm in diameter within about 5% of variation. The present method has advantages such as good sphericity, few satellite droplets, active control of the microsphere diameter, and high throughput with the simple and low cost process. To achieve the promising results, this integrating method reveals high potential for production of polymer based microspheres.

Micromachines ◽  
2021 ◽  
Vol 12 (6) ◽  
pp. 662
Author(s):  
Nikita A. Filatov ◽  
Anatoly A. Evstrapov ◽  
Anton S. Bukatin

Droplet microfluidics is an extremely useful and powerful tool for industrial, environmental, and biotechnological applications, due to advantages such as the small volume of reagents required, ultrahigh-throughput, precise control, and independent manipulations of each droplet. For the generation of monodisperse water-in-oil droplets, usually T-junction and flow-focusing microfluidic devices connected to syringe pumps or pressure controllers are used. Here, we investigated droplet-generation regimes in a flow-focusing microfluidic device induced by the negative pressure in the outlet reservoir, generated by a low-cost mini diaphragm vacuum pump. During the study, we compared two ways of adjusting the negative pressure using a compact electro-pneumatic regulator and a manual airflow control valve. The results showed that both types of regulators are suitable for the stable generation of monodisperse droplets for at least 4 h, with variations in diameter less than 1 µm. Droplet diameters at high levels of negative pressure were mainly determined by the hydrodynamic resistances of the inlet microchannels, although the absolute pressure value defined the generation frequency; however, the electro-pneumatic regulator is preferable and convenient for the accurate control of the pressure by an external electric signal, providing more stable pressure, and a wide range of droplet diameters and generation frequencies. The method of droplet generation suggested here is a simple, stable, reliable, and portable way of high-throughput production of relatively large volumes of monodisperse emulsions for biomedical applications.


Author(s):  
Mats Nordlund ◽  
Taesik Lee ◽  
Sang-Gook Kim

In 1977, Nam P Suh proposed a different approach to design research. Suh’s approach was different in that it introduced the notions of domains and layers in a 2-D design thinking and stipulated a set of axioms that describes what is a good design. Following Suh’s 2-D reasoning structure in a zigzagging manner and applying these axioms through the design process should enable the designer to arrive at a good design. In this paper, we present our own experiences in applying Suh’s theories to software design, product design, organizational design, process design, and more in both academic and industrial settings. We also share our experience from teaching the Axiomatic Design theory to students at universities and engineers in industry, and draw conclusions on how best to teach and use this approach, and what results one can expect. The merits of the design axioms are discussed based on the practical experiences that the authors have had in their application. The process developed around the axioms to derive maximum value (solution neutral environment, design domains, what-how relationship, zig-zag process, decomposition, and design matrices) is also discussed and some updates are proposed.


2015 ◽  
Vol 32 (1) ◽  
pp. 3-17
Author(s):  
Naresh K. Sharma ◽  
Elizabeth A. Cudney

Purpose – Complexity is an important element in axiomatic design theory. The current method for calculating complexity for a system following normal distribution is unbounded and approximate. The purpose of this paper is to present a detailed bounded solution for complexity using design and system ranges on a single function requirement. Design/methodology/approach – This paper discusses the complexity measure for a system following a uniform distribution. The complexities of two types of systems, a system performing with a uniform distribution and a system performing on target according to a normal distribution are then considered and compared. The research proposes a complexity measure for a system performing within specification limits with a uniform distribution. In addition, a new concept of relative complexity is proposed. Findings – A bounded solution for complexity for a normal distribution based on the existing assumptions was given which includes bias in addition to variance. The bounded solution was then compared to the existing approximate solution from the variance as well as bias standpoint. It was found that bias has an inappropriately reverse relationship with the bounded solution of complexity. Therefore, complexity cannot be used to approximate the system improvement when the improvement is based on a reduction in bias. Originality/value – The current method for calculating complexity for a system following normal distribution is unbounded and approximate. This paper proposed a complexity measure for a system performing within specification limits with a uniform distribution.


Author(s):  
Johan Vallhagen

Abstract In earlier work, the axiomatic design theory has been analyzed for applications on product design and the production processes that pertain to it, where parts manufacture and assembly take place in flexible and automatic manufacturing systems. The conclusion is that the original model cannot handle the manufacturing aspects in a satisfactory manner. This report proposes an expansion of the axiomatic design model, with a life-cycle approach as take-off. The expansion of the model consists of the introduction of a so-called Manufacturing World with different spaces, where various types of processes and support functions can be developed in agreement with the axiomatic principles. The spaces and their relationships have been defined along with explanations of work procedures. An explanatory example is given.


2018 ◽  
Vol 223 ◽  
pp. 01021
Author(s):  
Oana Dodun ◽  
Ema Panaite ◽  
Petru Duşa ◽  
Gheorghe Nagît ◽  
Margareta Coteată ◽  
...  

Ultrasonic abrasive cavitational machining is a nonconventional machining method applied to remove surfaces in workpieces made of brittle, hard, or non-conductive materials that cannot be efficiently machined by other classical or nonconventional machining methods. Among the factors that can affect the values of the parameters of technological interest for the ultrasonic machining process, the relative pressure between the ultrasonic tool and the workpiece surface to be machined could be considered. The main objective of the research presented in this paper was to analyze the possibilities of selecting the most convenient solution among many such available solutions to ensure the tool feed motion, when designing a device for achieving an ultrasonic drilling process. At present, this selection could be achieved by means of an optimal selection method. Taking into consideration some functional requirements of the device, the method of analytic hierarchy process and the axiomatic design theory were used to solve some problems met in the design process.


2019 ◽  
Vol 301 ◽  
pp. 00015
Author(s):  
Wenguang Lin ◽  
Renbin Xiao ◽  
Rongshen Lai ◽  
Xiaozhen Guo

Axiomatic design theory is widely used in new product development by providing design solutions through mapping between functional requirements and design parameters. However, the theory does not provide a method to help designer obtain and select design parameters. To this end, this paper introduces patent analysis to overcome the deficiency. Firstly, functional requirements are transformed into patent search terms, and design parameters are obtained from patents. Secondly, morphological matrix is used to represent the relationships between target function and multiple design parameters. Thirdly, design parameters with higher patent frequency are chose and combined into a new scheme. Finally, the scheme is evaluated by the independent axiom of Axiomatic Design theory. The methodology is demonstrated and validated with a case study of spa shower.


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