scholarly journals Spatial Limit of CFD Model at Nanometer Scale Geometry: Part I: Capillary Flow

2020 ◽  
Vol 5 (7) ◽  
pp. 795-799
Author(s):  
Simon Mark ◽  
Harry Boyer
Keyword(s):  
Numerical Simulation ◽  
Capillary Flow ◽  
Numerical Models ◽  
New Technology ◽  
Small Scale ◽  
Lab On Chip ◽  
Potential Error ◽  
Passive Flow ◽  
On Chip ◽  
The Continuum

Numerical simulation using computational fluid dynamics has been studied broadly in various fields of applications. Along with the advancement in new technology especially those employing micro or nanoscale geometries or lab-on-chip devices, it is important to understand the efficiency of such numerical models at small geometrical scales. To access any potential error in numerical simulation using CFD, in the present work we report the investigation of capillary driven passive flow inside a channel of varying geometry. The potential error in the results of simulation at a very small scale is accessed by comparing it with the results of theoretical analysis. Hence, establishes a spatial limit of the continuum model for simulation in related applications. This gives new insight to the further study on CFD at nanometers scale geometry.

Integrated Microfluidic Flow Sensor for LAB-oN-CHIP and PoINT-oF-CARE Applications

2020 ◽  
Vol 36 (4) ◽  
pp. 112-120
Author(s):  
A.V. Zverev ◽  
M. Andronik ◽  
V.V. Echeistov ◽  
Z.H. Issabayeva ◽  
O.S. Sorokina ◽  
...  
Keyword(s):  
Numerical Simulation ◽  
Flow Rate ◽  
Microfluidic Chip ◽  
Soft Lithography ◽  
Point Of Care ◽  
Flow Sensor ◽  
Oxide Semiconductor ◽  
Dead Volume ◽  
Lab On Chip ◽  
On Chip

The results of the development and manufacture of an integrated membrane-free sensor for the control of accurate dilution of liquid samples on the microfluidic chip are presented. The proposed type of devices is intended for direct precise measurements of liquid flow rate in microchannels of laboratories-on-chip, including point-of-care systems. The sensor topology was optimized based on the numerical simulation results and technological requirements. The main characteristic of the developed sensor is the lack of a membrane in the design while maintaining the sensitivity and accuracy of the device at the level of a commercial membrane analogue. The fully biocompatible sensor was manufactured using standard microelectronics and soft lithography technologies. In order to optimize the sensor design, 32 different topologies of the device were tested. The integration of the flow sensors on the chip allows to significantly reduce the dead volume of the hydrodynamic system and to control the amount of liquid entering the individual reservoirs of the microfluidic chip. The sensor occupies an area of (210 x 140) um2 in the channel and is characterized by a relative error of 5% in the flow rate range of 100-1000 ul/min. microfluidics, lab-on-chip, calorimetric flow sensor, thermoresistive sensor, numerical simulation, hydrodynamics, complementary metal-oxide-semiconductor, microtechnologies Devices were made at the BMSTU Nanofabrication Facility (FMN Laboratory, FMNS REC, ID 74300).

scholarly journals Rapid Microfluidic Mixer Based on Ferrofluid and Integrated Microscale NdFeB-PDMS Magnet

Micromachines ◽  
2019 ◽  
Vol 11 (1) ◽  
pp. 29
Author(s):  
Ran Zhou ◽  
Athira N. Surendran ◽  
Marcel Mejulu ◽  
Yang Lin
Keyword(s):  
Numerical Models ◽  
Low Cost ◽  
Industrial Applications ◽  
Mass Ratio ◽  
Biochemical Engineering ◽  
Lab On Chip ◽  
Microfluidic Mixer ◽  
Mixing Performance ◽  
On Chip ◽  
Flow Experiments

Ferrofluid-based micromixers have been widely used for a myriad of microfluidic industrial applications in biochemical engineering, food processing, and detection/analytical processes. However, complete mixing in micromixers is extremely time-consuming and requires very long microchannels due to laminar flow. In this paper, we developed an effective and low-cost microfluidic device integrated with microscale magnets manufactured with neodymium (NdFeB) powders and polydimethylsiloxane (PDMS) to achieve rapid micromixing between ferrofluid and buffer flow. Experiments were conducted systematically to investigate the effect of flow rate, concentration of the ferrofluid, and micromagnet NdFeB:PDMS mass ratio on the mixing performance. It was found that mixing is more efficient with lower total flow rates and higher ferrofluid concentration, which generate greater magnetic forces acting on both streamwise and lateral directions to increase the intermixing of the fluids within a longer residence time. Numerical models were also developed to simulate the mixing process in the microchannel under the same conditions and the simulation results indicated excellent agreements with the experimental data on mixing performance. Combining experimental measurements and numerical simulations, this study demonstrates a simple yet effective method to realize rapid mixing for lab-on-chip systems.

Gut microbiome a promising target for management of respiratory diseases

2020 ◽  
Vol 477 (14) ◽  
pp. 2679-2696
Author(s):  
Riddhi Trivedi ◽  
Kalyani Barve
Keyword(s):  
Respiratory Diseases ◽  
New Technology ◽  
Bacterial Flora ◽  
Systemic Circulation ◽  
The Body ◽  
Lung Pathology ◽  
Promising Target ◽  
Current Therapies ◽  
Intestinal Microbial Flora ◽  
On Chip

The intestinal microbial flora has risen to be one of the important etiological factors in the development of diseases like colorectal cancer, obesity, diabetes, inflammatory bowel disease, anxiety and Parkinson's. The emergence of the association between bacterial flora and lungs led to the discovery of the gut–lung axis. Dysbiosis of several species of colonic bacteria such as Firmicutes and Bacteroidetes and transfer of these bacteria from gut to lungs via lymphatic and systemic circulation are associated with several respiratory diseases such as lung cancer, asthma, tuberculosis, cystic fibrosis, etc. Current therapies for dysbiosis include use of probiotics, prebiotics and synbiotics to restore the balance between various species of beneficial bacteria. Various approaches like nanotechnology and microencapsulation have been explored to increase the permeability and viability of probiotics in the body. The need of the day is comprehensive study of mechanisms behind dysbiosis, translocation of microbiota from gut to lung through various channels and new technology for evaluating treatment to correct this dysbiosis which in turn can be used to manage various respiratory diseases. Microfluidics and organ on chip model are emerging technologies that can satisfy these needs. This review gives an overview of colonic commensals in lung pathology and novel systems that help in alleviating symptoms of lung diseases. We have also hypothesized new models to help in understanding bacterial pathways involved in the gut–lung axis as well as act as a futuristic approach in finding treatment of respiratory diseases caused by dysbiosis.

scholarly journals The Effectiveness of Ensemble-Neural Network Techniques to Predict Peak Uplift Resistance of Buried Pipes in Reinforced Sand

2021 ◽  
Vol 11 (3) ◽  
pp. 908
Author(s):  
Jie Zeng ◽  
Panagiotis G. Asteris ◽  
Anna P. Mamou ◽  
Ahmed Salih Mohammed ◽  
Emmanuil A. Golias ◽  
...  
Keyword(s):  
Neural Network ◽  
Numerical Models ◽  
Correlation Coefficients ◽  
Network Models ◽  
Small Scale ◽  
Offshore Platforms ◽  
Neural Network Models ◽  
Buried Pipes ◽  
Ensemble Techniques ◽  
Uplift Resistance

Buried pipes are extensively used for oil transportation from offshore platforms. Under unfavorable loading combinations, the pipe’s uplift resistance may be exceeded, which may result in excessive deformations and significant disruptions. This paper presents findings from a series of small-scale tests performed on pipes buried in geogrid-reinforced sands, with the measured peak uplift resistance being used to calibrate advanced numerical models employing neural networks. Multilayer perceptron (MLP) and Radial Basis Function (RBF) primary structure types have been used to train two neural network models, which were then further developed using bagging and boosting ensemble techniques. Correlation coefficients in excess of 0.954 between the measured and predicted peak uplift resistance have been achieved. The results show that the design of pipelines can be significantly improved using the proposed novel, reliable and robust soft computing models.

scholarly journals A Lab‐On‐chip Tool for Rapid, Quantitative, and Stage‐selective Diagnosis of Malaria

2021 ◽  
pp. 2004101
Author(s):  
Marco Giacometti ◽  
Francesca Milesi ◽  
Pietro Lorenzo Coppadoro ◽  
Alberto Rizzo ◽  
Federico Fagiani ◽  
...  
Keyword(s):  
Lab On Chip ◽  
On Chip

scholarly journals Integrated Magnetohydrodynamic Pump with Magnetic Composite Substrate and Laser-Induced Graphene Electrodes

Polymers ◽  
2021 ◽  
Vol 13 (7) ◽  
pp. 1113
Author(s):  
Mohammed Asadullah Khan ◽  
Jürgen Kosel
Keyword(s):  
Magnetic Flux ◽  
Flow Rate ◽  
Magnetic Composite ◽  
Propulsive Force ◽  
Closed Channel ◽  
Lab On Chip ◽  
Composite Substrate ◽  
On Chip ◽  
High Level ◽  
Moving Parts

An integrated polymer-based magnetohydrodynamic (MHD) pump that can actuate saline fluids in closed-channel devices is presented. MHD pumps are attractive for lab-on-chip applications, due to their ability to provide high propulsive force without any moving parts. Unlike other MHD devices, a high level of integration is demonstrated by incorporating both laser-induced graphene (LIG) electrodes as well as a NdFeB magnetic-flux source in the NdFeB-polydimethylsiloxane permanent magnetic composite substrate. The effects of transferring the LIG film from polyimide to the magnetic composite substrate were studied. Operation of the integrated magneto hydrodynamic pump without disruptive bubbles was achieved. In the studied case, the pump produces a flow rate of 28.1 µL/min. while consuming ~1 mW power.

scholarly journals Towards lab-on-chip ultrasensitive ethanol detection using photonic crystal waveguide operating in the mid infrared

Nanophotonics ◽  
2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Ali Rostamian ◽  
Ehsan Madadi-Kandjani ◽  
Hamed Dalir ◽  
Volker J. Sorger ◽  
Ray T. Chen
Keyword(s):  
Photonic Crystal ◽  
Slow Light ◽  
High Sensitivity ◽  
Guided Wave ◽  
Silicon On Insulator ◽  
Group Index ◽  
Photonic Crystal Waveguide ◽  
Mid Infrared ◽  
Lab On Chip ◽  
On Chip

Abstract Thanks to the unique molecular fingerprints in the mid-infrared spectral region, absorption spectroscopy in this regime has attracted widespread attention in recent years. Contrary to commercially available infrared spectrometers, which are limited by being bulky and cost-intensive, laboratory-on-chip infrared spectrometers can offer sensor advancements including raw sensing performance in addition to use such as enhanced portability. Several platforms have been proposed in the past for on-chip ethanol detection. However, selective sensing with high sensitivity at room temperature has remained a challenge. Here, we experimentally demonstrate an on-chip ethyl alcohol sensor based on a holey photonic crystal waveguide on silicon on insulator-based photonics sensing platform offering an enhanced photoabsorption thus improving sensitivity. This is achieved by designing and engineering an optical slow-light mode with a high group-index of n g  = 73 and a strong localization of modal power in analyte, enabled by the photonic crystal waveguide structure. This approach includes a codesign paradigm that uniquely features an increased effective path length traversed by the guided wave through the to-be-sensed gas analyte. This PIC-based lab-on-chip sensor is exemplary, spectrally designed to operate at the center wavelength of 3.4 μm to match the peak absorbance for ethanol. However, the slow-light enhancement concept is universal offering to cover a wide design-window and spectral ranges towards sensing a plurality of gas species. Using the holey photonic crystal waveguide, we demonstrate the capability of achieving parts per billion levels of gas detection precision. High sensitivity combined with tailorable spectral range along with a compact form-factor enables a new class of portable photonic sensor platforms when combined with integrated with quantum cascade laser and detectors.

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