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Статті в журналах з теми "Micro fluidic POCD"
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Pugia, Michael J., Gert Blankenstein, Ralf-Peter Peters, James A. Profitt, Klaus Kadel, Thomas Willms, Ronald Sommer, Hai Hang Kuo, and Lloyd S. Schulman. "Microfluidic Tool Box as Technology Platform for Hand-Held Diagnostics." Clinical Chemistry 51, no. 10 (October 1, 2005): 1923–32. http://dx.doi.org/10.1373/clinchem.2005.052498.
Повний текст джерелаАнотація:
Abstract Background: Use of microfluidics in point-of-care testing (POCT) will require on-board fluidics, self-contained reagents, and multistep reactions, all at a low cost. Disposable microchips were studied as a potential POCT platform. Methods: Micron-sized structures and capillaries were embedded in disposable plastics with mechanisms for fluidic control, metering, specimen application, separation, and mixing of nanoliter to microliter volumes. Designs allowed dry reagents to be on separate substrates and liquid reagents to be added. Control of surface energy to ±5 dyne/cm2 and mechanical tolerances to ≤1 μm were used to control flow propulsion into adsorptive, chromatographic, and capillary zones. Fluidic mechanisms were combined into working examples for urinalysis, blood glucose, and hemoglobin A1c testing using indicators (substances that react with analyte, such as dyes, enzyme substrates, and diazonium salts), catalytic reactions, and antibodies as recognition components. Optical signal generation characterized fluid flow and allowed detection. Results: We produced chips that included capillary geometries from 10 to 200 μm with geometries for stopping and starting the flow of blood, urine, or buffer; vented chambers for metering and splitting 100 nL to 30 μL; specimen inlets for bubble-free specimen entry and containment; capillary manifolds for mixing; microstructure interfaces for homogeneous transfer into separation membranes; miniaturized containers for liquid storage and release; and moisture vapor barrier seals for easy use. Serum was separated from whole blood in <10 s. Miniaturization benefits were obtained at 10–200 μm. Conclusion: Disposable microchip technology is compatible with conventional dry-reagent technology and allows a highly compact system for complex assay sequences with minimum manual manipulations and simple operation.
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Sathish, Dhandapani, and Selvaraj Jegadheeswaran. "Experimental Investigation on a Novel Composite Salt Gradient Solar Pond With an East–West Side Reflector." Journal of Thermal Science and Engineering Applications 14, no. 3 (June 22, 2021). http://dx.doi.org/10.1115/1.4051243.
Повний текст джерелаАнотація:
Abstract A salt gradient solar pond (SGSP) acts as an eco-friendly and cost-efficient device for storing thermal energy storage. It is crucial to enrich the efficiency of the SGSP to boost its thermal energy storage. It can be efficaciously achieved with the application of salt mixtures, reflectors, and by the usage of a glazed layer. This current study investigates the hexagonal composite salinity gradient solar pond (HCSGSP) augmented with a dual inclined reflector and a triple-layer transparent cover. A micro-solar pond having a hexagonal cross section was fabricated and experimented at Coimbatore, India, having a datum and surface area of 1 m and 0.679 m2, respectively. The novel usage of composite salt (sodium chloride 30%, magnesium chloride 10%, and potassium chloride 60%) led to the enhancement of the daily average temperature of pond. The pond’s upper portion was packed with a triple-layer glazed cover which shows an uplift of thermal energy and the pond is provided with inclined reflectors made of plywood fixed with mirrors on the east–west direction. The purpose of the mirrors is to increase the solar radiation intensity during the diurnal period and also it acts as an insulator which minimizes the heat losses during the nocturnal period. Energy balance numerical equations were formulated for all layers in the pond and temperature variation was determined mathematically and experimentally. The maximum thermal efficiencies of the top convective, middle non-convective, and bottom convective layers of reformed solar pond were measured to be 23.44%, 30.68%, and 35.63%, respectively, whereas they were 1.32%, 12.32%, and 23.44%, respectively, in the case of conventional pond. Furthermore, the research provides insight into the impact of shading owing to sidewalls, which has a significant impact on the incident solar radiation and storage of thermal energy in the novel solar pool.
Дисертації з теми "Micro fluidic POCD"
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Fan, Xiaozhou. "Canonical Decomposition of Wing Kinematics for a Straight Flying Insectivorous Bat." Thesis, Virginia Tech, 2018. http://hdl.handle.net/10919/91469.
Повний текст джерелаАнотація:
Bats are some of the most agile flyers in nature. Their wings are highly articulated which affords them very fine control over shape and form. This thesis investigates the flight of Hipposideros Pratti. The flight pattern studied is nominally level and straight. Measured wing kinematics are used to describe the wing motion. It is shown that Proper Orthogonal Decomposition (POD) can be used to effectively to filter the measured kinematics to eliminate outliers which usually manifest as low energy higher POD modes, but which can impact the stability of aerodynamic simulations. Through aerodynamic simulations it is established that the first two modes from the POD analysis recover 62% of the lift, and reflect a drag force instead of thrust, whereas the first three modes recover 77% of the thrust and even more lift than the native kinematics. This demonstrates that mode 2, which features a combination of spanwise twisting (pitching) and chordwise cambering, is critical for the generation of lift, and more so for thrust. Based on these inferences, it is concluded that the first 7 modes are sufficient to represent the full native kinematics.
The aerodynamic simulations are conducted using the immersed boundary method on 128 processors. They utilize a grid of 31 million cells and the bat wing is represented by about 50000 surface elements. The movement of the immersed wing surface is defined by piecewise cubic splines that describe the time evolution of each control point on the wing.
The major contribution of this work is the decomposition of the native kinematics into canonical flapping wing physical descriptors comprising of the flapping motion, stroke-plane deviation, pitching motion, chordwise, and spanwise cambering. It is shown that the pitching mode harvests a Leading Edge Vortex (LEV) during the upstroke to produce thrust. It also stabilizes the LEV during downstroke, as a result, larger lift and thrust production is observed. Chordwise cambering mode allows the LEV to glide over and cover a large portion of the wing thus contributing to more lift while the spanwise cambering mode mitigates the intensification of LEV during the upstroke by relative rotation of outer part of the wing ( hand wing ) with respect to the inner part of the wing ( arm wing).
While this thesis concerns itself with near straight-level flight, the proposed decomposition can be applied to any complex flight maneuver and provide a basis for unified comparison not only over different bat flight regimes but also across other flying insects and birds.MS
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Monteiro, Miguel Pedro da Conceição. "Flexible sensors technology for Point-Of-Care diagnostics with integrated micro fluidics on paper." Master's thesis, 2018. http://hdl.handle.net/10362/61574.
Повний текст джерелаАнотація:
Nowadays the hospitals and the medical centres face a huge challenge finding solutions to improve the efficiency of medical diagnosis.
The scope of this project was to develop a “Point-of-Care Diagnostic” (POCD) device, that can give a better alternative for genetic analysis, instead of the usual methods of PCR (polymerase chain reaction).
This device is composed by three layers. The first layer which works as a transporter and filter was built on paper. The second layer is the substitute of the regular thermocycling phase in the PCR technique and the third layer incorporates an interdigital capacitor that works as a DNA (deoxyribonucleic acid) sensor with high sensitivity to detect DNA hybridisation. These last two layers were made in kapton film.
The devices were produced with microfabrication methods using inkjet printing, lithographic and deposition processes.
The device’s characterisation was based on impedance spectroscopy methods.
With the purpose of testing the device, the capacitor was functionalised with the YWHAZ gene. However, this process can be performed with any other gene.
Due to its characteristics, the device under study was designed to run RT-qPCR (Real time quantitative polymerase chain reaction) and presents itself as an effective way to substitute the traditional PCR techniques. Even more, as the transport of samples to a laboratory and the recruitment of specialised personnel are not necessary, costs and response time are reduced.
Тези доповідей конференцій з теми "Micro fluidic POCD"
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Hao, Wentao, Ling Tian, and Bingshu Tong. "Macromodeling Method of Fluid-Structure Interacting MEMS Based on Modal Analysis and Proper Orthogonal Decomposition." In 2007 First International Conference on Integration and Commercialization of Micro and Nanosystems. ASMEDC, 2007. http://dx.doi.org/10.1115/mnc2007-21289.
Повний текст джерелаАнотація:
Because of their good performance to speed up MEMS system simulation processes, macromodels have aroused lots of attentions of scientists in the last decades. However, studies on FSI (Fluid-Structure Interaction) MEMS devices still can not satisfy the macromodeling requests because of the high complexity of fluid fields. A new method based on modal analysis and POD (Proper Orthogonal Decomposition) is tentatively put forward to reduce the order of FSI MEMS models. The structure macromodeling theory is firstly reviewed. Then the fluid field macromodeling approach is discussed in detail. At last, a 2D fixed-fixed micro-beam is analyzed and the results show that the macromodel extracted in this method can highly decrease the system degrees of freedom, while its precision is still comparable with that of detailed models.
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Georgiou, Ioannis T. "Reduction of the Impact-Induced Experimental Dynamics of a Foam-Filled Thin-Walled Aluminum Beam Interacting With Water." In ASME 2011 International Mechanical Engineering Congress and Exposition. ASMEDC, 2011. http://dx.doi.org/10.1115/imece2011-62887.
Повний текст джерелаАнотація:
We applied a novel sensing and data processing technique to analyze the water-interaction dynamics of a thin-walled aluminum beam filled with micro-structured material. The spatial impulse response is sensed at three spatial points in the form of ensembles of collocated acceleration signals. Processed by the powerful POD Transforms, the modal-like decomposition of collocated acceleration signals provides interesting insight on the nature of impulse-induced vibrations of this complex structure-water system. When not interacting with water, the point impulse excited structure vibrates in a dominant POD mode with energy-transfer wave form characteristics. When interacting with water, the point impulse excited structure vibrates in two POD modes. One POD mode is vibration while the other one is rigid-flexible body motion. The POD modes capture characteristics of interactions between flexible body (vibration-wave) and rigid body motions. This modal identification technique is potentially useful for reduced model identification and parameter estimation of hard to model complex structural-fluid interacting systems encountered in aerospace and ocean environments.
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Yafia, Mohamed, and Homayoun Najjaran. "Low Cost Graphene Electrodes for Performing Digital Microfluidic Operations on a Hand Held Portable Platform." In ASME 2016 14th International Conference on Nanochannels, Microchannels, and Minichannels collocated with the ASME 2016 Heat Transfer Summer Conference and the ASME 2016 Fluids Engineering Division Summer Meeting. American Society of Mechanical Engineers, 2016. http://dx.doi.org/10.1115/icnmm2016-8078.
Повний текст джерелаАнотація:
This work presents a new fabrication method for the electrodes of digital microfluidic (DMF) systems in which the electrodes are fabricated from laser scribed graphene on PET substrates. The new fabrication method helps in rapid design and prototyping of the DMF electrodes easily without a need for highly equipped facilities. The electrodes are fabricated on flexible substrates. Hence, the prospered method improves both the versatility of the DMF chips as we can form them to any desirable shape. The laser scribed graphene chips are then inserted to a battery-powered handheld DMF device to perform different applications such as point of care testing (POCT). The portable device is controlled using a smartphone via a Bluetooth connection. The DMF droplets are magnified using a micro lens installed on top of the smartphone camera to monitor and record DMF processes.
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Ferguson, Steven E., Evan C. Lemley, and Mohammad R. Hossan. "Second Law Analysis of Passive Micro-Mixing in Rectangular Microchannels With Flow Obstacles." In ASME 2017 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 2017. http://dx.doi.org/10.1115/imece2017-72328.
Повний текст джерелаАнотація:
Passive micromixers have application in the biosciences area. In particular, passive micromixers that may be used as part of point-of-care (POC) diagnostic testing devices are becoming common-place and have application in developed, developing, and relatively undeveloped locales. Characterizing and improving mixing efficiency in these devices is an ongoing research effort. Different channel geometries and flow obstacles lead to varying degrees of mixing effectiveness and serve to increase chaotic advective mixing in contrast to the molecular diffusive mixing that occurs even in the absence of these obstacles. Entropy is generated due to these, and other, irreversible processes. Efficient micromixer design is of interest to biomedical and mechanical engineers working in the biosciences area. The entropy generation rate, we contend, can provide an aid in determining how thoroughly mixed fluids in the channel have become, as well as provide insight into improving channel design to maximize desired outcomes, such as mixing, and minimizing losses due to heat transfer and power consumption. In this paper, we focus our analysis on numerical simulations conducted using computational fluid dynamics (CFD) on a supercomputer-cluster to do simulations with extended mesh refinement and very small residuals. This enabled us to test a wide range of flows with varying Reynolds numbers. The configuration of flow and species parameters within the simulations were compared to experimental results to confirm their validity. We show that varying the geometry of the channel can lead to a measurable increase in entropy generation via the Second Law of Thermodynamics. Further, we show that this increase in entropy is linked to mixing from obstacle-induced chaotic advection and diffusion. We provide evidence of a positive correlation between the efficiency of the mixing process and entropy generation. These findings will aid in the design of more efficient portable health care-related devices, particular in remote or underdeveloped regions where power utilization is a critical concern.
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Pandit, Jayanth, Bhanuprakash Kunam, Omar Cavazos, and Maurizio Manzo. "Fabrication of Photonic Microlasers via Microfluidic Double Emulsion." In ASME 2022 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 2022. http://dx.doi.org/10.1115/imece2022-95994.
Повний текст джерелаАнотація:
Abstract Fluid control at a micro-level features unique properties that can be utilized to develop devices capable of biosensing. Microfluidics is a branch of technology that deals with microfluidic channels and the fluids confined within those channels. Singular droplets can be produced when perpendicular streams of immiscible fluids intersect with the main fluid stream. This intersecting stream must be different than the main fluid stream. One fundamental way of fabricating the spheres includes using a stream of water and oil. As oil and water do not mix, the stream of oil will separate the water stream and release a singular droplet. Photonic spherical microlasers manufactured by microfluidic systems exhibit a more consistent size control and are mass-produced easily; by controlling the pressure or flow rate of both dispersed phase and continuous phase, the size of the microlaser can be precisely controlled. The use of microlasers can open several paths toward susceptible sensing systems in a variety of biomedical applications, such as cancer detection and nerve cell electric potential detection via voltage-sensitive dyes. In the past, such sensing systems have been created using different UV curable biocompatible polymers doped with laser dyes. In this work, we consider testing various configurations of immiscible fluids for the disperse and continuous phases. Not only that, but the use of double emulsion microlasers will be advantageous over single emulsion types due to a promising increase of versatility in terms of multiplexed sensing and broad applications. This new solution involves microfluidic pumps and a flow-focusing droplet generator chip with microfluidic channels fabricated with polydimethylsiloxane (PDMS) and polycarbonate. Factors like the flow rate (Q) and pressure (P) of both continuous and dispersed phases determine the size of both the core and shell of these double emulsion droplets, which are made solid-state via the UV curing process. These sensors involve the whispering-gallery-mode phenomenon, where laser light is coupled to the microlaser generating optical resonances; the incoming photons resonate because light waves propagate throughout the inner walls of the sphere. This resonance can be shifted due to external conditions that change the traveling light’s optical path. The changes in the optical spectrum are monitored by using an optical spectrometer. Such sensors have the potential to be implemented as point-of-care (POC) devices and have the prospect of growing and becoming an impactful technology in biomedical research and industry.
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Gillispie, Aric M., and Evan C. Lemley. "Correlation of Mixing Efficiency and Entropy Generation Rate in a Square Cross Section Tee Junction Micromixer." In ASME 2017 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 2017. http://dx.doi.org/10.1115/imece2017-72288.
Повний текст джерелаАнотація:
The potential applications of micromixers continues to expand in the bio-sciences area. In particular, passive micromixers that may be used as part of point-of-care (POC) diagnostic testing devices are becoming commonplace and have application in developed, developing, and relatively undeveloped locales. Characterizing and improving mixing efficiency in these devices is an ongoing research effort. Micromixers are used in some lab-on-chip (LOC) devices where it is often necessary to combine two or more fluids into a mixed solution for testing or delivery. The simplest micromixer incorporates a tee junction to combine two fluid species in anti-parallel branches, with the mixed fluid leaving in a branch perpendicular to the incoming branches. Micromixers rely on two modes of mixing: chaotic advection and molecular diffusion. In micro-mixers flow is typically laminar, making chaotic advection occur only via induced secondary flows. Hence, micromixers, unless carefully designed, rely almost exclusively on molecular diffusion of fluid species. A well designed micromixer should exhibit significant chaotic advection; which is also a sign of large strain rates and large entropy generation rates. This paper describes the development of an analytical relationship for the entropy generation rate and the mixing efficiency as function of the outgoing branch Reynolds number. Though there has been extensive research on tee junctions, entropy generation, and the mixing efficiencies of a wide variety of micromixers, a functional relationship for the mixing efficiency and the entropy generation rate has not been established. We hypothesize a positive correlation between the mixing index and the entropy generation rate. The worked described here establishes a method and provides the results for such a relationship. A basic tee junction with square cross sections has been analyzed using computational fluid dynamics to determine the entropy generation rate and outgoing mixing efficiencies for Reynolds numbers ranging from 25–75. The mixing efficiency is determined at a location in the outgoing branch where the effects of molecular diffusive mixing is minimized and chaotic advective mixing is the focus. The entropy generation rate has been determined for the indicated range of Reynolds number and decomposed into its viscous and diffusive entropy terms. The functional relationships that have been developed are applicable for micromixer design and serve as a reference for more complex passive micromixer designs.