Non-volatile liquid-film-embedded microfluidic valve for microscopic evaporation control and contactless bio-fluid delivery applications

Quick evaporation speed of microfluids can cause many unexpected problems and failures in various microfluidic devices and systems. In this dissertation, a new evaporation speed controlling method is demonstrated using a thin liquid-film based microfluidic valve. Microfluidic droplet ejectors were designed, fabricated and integrated with the liquid-film based microfluidic valve. The thin liquid film with nonvolatility and immiscibility exhibited excellent microfluidic valve functionality without any stiction problem between valve components, and provided a very effective evaporation protection barrier for the microfluids in the device. Successful evaporation control by the liquid-film-embedded (LiFE) microfluidic valve has been demonstrated. In addition, guided actuation of the microfluidic valve along predefined paths was successfully achieved using newly developed oil-repellent surfaces, which were later used for developing ‘virtual walls’ for confining low surface tension liquids within predefined areas. Moreover, bioinspired slippery surfaces for aiding the microfluidic valve along the ejector surface have also been developed. These slippery surfaces were evaluated for their effectiveness in reducing microfluidic valve driving voltages. Finally, a sliding liquid drop (SLID) shutter technique has been developed for a normally closed functionality with aid from nanostructures. The SLID shutter resolves many issues found in the previous LiFE microfluidic valve. Smooth and successful printing results of highly volatile bio-fluids have been demonstrated using the SLID shutter technique. I envision that these demonstrated techniques and developed tools have immense potential in various microfluidic applications

NASA SBIR abstracts of 1992, phase 1 projects

The objectives of 346 projects placed under contract by the Small Business Innovation Research (SBIR) program of the National Aeronautics and Space Administration (NASA) are described. These projects were selected competitively from among proposals submitted to NASA in response to the 1992 SBIR Program Solicitation. The basic document consists of edited, non-proprietary abstracts of the winning proposals submitted by small businesses. The abstracts are presented under the 15 technical topics within which Phase 1 proposals were solicited. Each project was assigned a sequential identifying number from 001 to 346, in order of its appearance in the body of the report. Appendixes to provide additional information about the SBIR program and permit cross-reference of the 1992 Phase 1 projects by company name, location by state, principal investigator, NASA Field Center responsible for management of each project, and NASA contract number are included

Micro-injection moulding of three-dimensional integrated microfluidic devices

This thesis investigates the use of micro-injection moulding (μIM), as a high-volume process, for producing three-dimensional, integrated microfluidic devices. It started with literature reviews that covered three topics: μIM of thermoplastic microfluidics, designing for three-dimensional (3-D) microfluidics and functional integration in μIM. Research gaps were identified: Designing 3-D microfluidics within the limitations of μIM, process optimisation and the integration of functional elements. A process chain was presented to fabricate a three-dimensional microfluidic device for medical application by μIM. The thesis also investigated the effect of processing conditions on the quality of the replicated component. The design-of-experiments (DOE) approach is used to highlight the significant processing conditions that affect the part mass taking into consideration the change in part geometry. The approach was also used to evaluate the variability within the process and its effect on the replicability of the process. Part flatness was also evaluated with respect to post-filling process parameters. The thesis investigated the possibility of integrating functional elements within μIM to produce microfluidic devices with hybrid structures. The literature reviews highlighted the importance of quality control in high-volume micromoulding and in-line functional integration in microfluidics. A taxonomy of process integration was also developed based on transformation functions. The experimental results showed that μIM can be used to fabricate microfluidic devices that have true three-dimensional structures by subsequent lamination. The DOE results showed a significant effect of individual process variables on the filling quality of the produced components and their flatness. The geometry of the replicated component was shown to have effect on influential parameters. Other variables, on the other hand, were shown to have a possible effect on process variability. Optimization statistical tools were used to improve multiple quality criteria. Thermoplastic elastomers (TPE) were processed with μIM to produce hybrid structures with functional elements.EThOS - Electronic Theses Online ServiceGBUnited Kingdo

Energy: A continuing bibliography with indexes

This bibliography lists 1920 reports, articles, and other documents introduced into the NASA Scientific and Technical Information System from July 1, 1980 through September 30, 1980