Fabrication for and Flow Visualization in 2.5D Rock-Based Ceramic Micromodels

2017 ◽  
Author(s):  
Daniel S. Park ◽  
J. Upadhyay ◽  
K. Sharmin ◽  
J. F. Robbins ◽  
I. Schoegl ◽  
...  
Keyword(s):  
Flow Visualization ◽  
Particle Concentration ◽  
Hot Embossing ◽  
Pore Network ◽  
Nano Particles ◽  
Low Flow ◽  
Fluorescence Signal ◽  
Metal Mold ◽  
Experimental Conditions ◽  
Thin Glass

A ceramic-based micromodel was fabricated with batching of green alumina ceramics mixed with polymer binders, extrusion of the green alumina tapes, and hot embossing of the green tapes with a metal mold. The metal mold fabricated using optical lithography of SU8 and electroforming of nickel contained 2.5D pore network geometry in 13 layers of a rock, Boise sandstone. The hot embossing process enabled the generation of the pore network geometries with a minimum feature size of 25 μm and for distinct formation of the 13 layers of the 2.5D pore geometry of the rock. The green ceramic micromodels were processed with solvent extraction, thermal debinding, and sintering. The sintered micromodels showed significant shrinkages at all directions of the micromodels, which were 17.6% in x, 17.5% in y, and 14.6% in z. The sintered, 2.5D rock-based ceramic micromodel was capped with a thin glass cover slide and used for flow visualization with a fluorescent dye and fluorescent nano-particles. The dye-filled micromodel showed good flow connectivity and fluorescence signal intensity dependence on depth. It was observed that the peak particle concentration close to the observation window and gradual decrease in particle concentration along the depth. The higher velocities were measured in the low flow resistance region with velocity variations along the depth. The microfabricated 2.5D ceramic micromodels will allow resistance to harsh experimental conditions such as high temperature and pressure, and opportunity for investigation of the complex flow patterns in 3D.

scholarly journals POSSIBILITIES OF SEMEN STAIN IDENTIFICATION AFTER CLOTHING AND BEDDING WASHING IN INVESTIGATING CASES OF SEXUAL ASSAULT

2020 ◽  
Vol 17 (34) ◽  
pp. 93-111
Author(s):  
Saule Amangeldievna MUSSABEKOVA
Keyword(s):  
Sexual Assault ◽  
Dna Analysis ◽  
Specific Antigen ◽  
Genetic Profile ◽  
Fluorescence Signal ◽  
Experimental Conditions ◽  
Physical Evidence ◽  
Crucial Component ◽  
Multiple Conditions

Identifying semen stains on clothing and bedding is a crucial component in investigating cases of sexual assault. In some cases, clothing and bedding have already been washed before they were removed and sent for forensic examination. There is insufficient data on best practices for handling traces of semen on clothes after washing. This work aimed to study the possibility of identifying traces of semen on clothes after washing using widely used techniques. To simulate typical physical evidence, donor semen samples were applied to pieces of clothing made from various fabrics. The clothes were washed under multiple conditions (with the help of nonbiological and biological (enzyme-containing) agents, and across numerous washing machines). After washing, the washing stains were characterized by the presence of fluorescence signal, spermatozoa (Koren – Stokis method), the determination of acid phosphatase, prostate-specific antigen and semenogelin, as well as the results of serological research according to the AB0 system and DNA analysis. Clothing analysis using these methods was shown to be effective in experimental conditions. However, the presence of enzymes as detergent components designed to destroy biogenic stains significantly affect the results of the identification of semen stains. It has been established that the full genetic profile can be obtained from semen stains even after washing three times. Different strategies are needed to detect, select and identify semen stains depending on the circumstances of a case. It is recommended to examine clothing and bedding, even if the specimens were previously washed.

scholarly journals Effect of Aerosil and Oleic Acid on Sedimentation of Magnetorheological Fluid

2019 ◽  
Vol 8 (12S2) ◽  
pp. 79-83
Keyword(s):  
Magnetic Field ◽  
Oleic Acid ◽  
Magnetic Force ◽  
Particle Concentration ◽  
Nano Particles ◽  
Carrier Fluid ◽  
Flux Lines ◽  
Smart Fluids ◽  
Magnetic Flux Lines ◽  
Ferro Magnetic

Magnetorheological Fluids (MRFs) are considered as smart fluids because they control viscosity using external magnetic field. It contains ferro-magnetic powder which are aligned in magnetic flux lines. The magnetic force between particles are controlled by magnetic field intensity. This controllable viscosity makes them acceptable in many mechanical applications, but due to difference in density between suspended particles and carrier fluid sedimentation is bound to occur. This thus creates the need of some additives. In our study, silica Nano particles (commercially known as Aerosil 200) is used as stabilizer and Oleic Acid is used as surfactant and their effect on sedimentation is studied in this article. Some other synthesis parameters like particle concentration, stirring duration and material loading also cause some change in sedimentation rate.

Aerodynamic Particle Resuspension due to Human and Model Foot Motions

2010 ◽  
Author(s):  
Yoshihiro Kubota ◽  
Hiroshi Higuchi
Keyword(s):  
Flow Visualization ◽  
Particle Concentration ◽  
Three Dimensional ◽  
Wall Jet ◽  
Piv Measurements ◽  
Particle Resuspension ◽  
Human Foot ◽  
Image Velocimetry ◽  
Foot Motion ◽  
Foot Tapping

Human foot motions such as walking and foot tapping detach the particulate matter on the floor and redistribute it, increasing the particle concentration in air. The objective of this paper is to experimentally investigate the mechanism of particle resuspension and redistribution due to human foot motion. In particular, generation and deformation of vortex produced by the foot motion and how they are affected by the shape of sole have been examined. The experiments were carried out by particle flow visualization and the Particle Image Velocimetry (PIV) measurements in air, and dye flow visualization in water. The flow visualizations with human foot tapping and stomping were also carried out in order to elucidate the particle resuspension in real situations. In a laboratory experiment, the foot was modeled either as an elongated plate or a foot wearing a slipper, moving normal to the ground downward or upward. To focus on the aerodynamic effect, the model foot was stopped immediately above the floor before contacting the floor. The results indicated that the particles were resuspended both in downward motion and in upward motion of the foot. The particle resuspension and redistribution were associated with the wall jet between the foot and floor and the vortex dynamics. With an elongated plate, three-dimensional vortex structure strongly affected the particle redistribution.

Design and Fabrication of Micro Hot Embossing Mold for Microfluidic Chip Used in Flow Cytometry

2007 ◽  
Vol 339 ◽  
pp. 246-251
Author(s):  
L.Q. Du ◽  
C. Liu ◽  
H.J. Liu ◽  
J. Qin ◽  
N. Li ◽  
...  
Keyword(s):  
Flow Cytometry ◽  
Microfluidic Chip ◽  
Low Cost ◽  
Hot Embossing ◽  
Microfluidic Chips ◽  
Metal Mold ◽  
Nickel Electroforming ◽  
Thick Photoresist ◽  
Nickel Base ◽  
Microfabrication Technology

Micro hot embossing mold of microfluidic chip used in flow cytometry is designed and microfabricated. After some kinds of microfabrication processes are tried, this paper presents a novel microfabrication technology of micro hot embossing metal mold. Micro metal mold is fabricated by low-cost UV-LIGA surface micro fabrication process using negative thick photoresist, SU-8. Different from other micro hot embossing molds, the micro mold with vertical sidewalls is fabricated by micro nickel electroforming directly on Nickel base. Based on the micro Nickel mold and automation fabrication system, high precision and mass-producing microfluidic chips have been fabricated and they have been used in flow cytometry

Microfabrication (Hot-Embossing) of COC Microfluidic Devices: Effect of Norbornene Content on Replication Fidelity and Surface Modification by UV-Photografting

2013 ◽  
Vol 543 ◽  
pp. 51-54
Author(s):  
Rajeeb Kumar Jena ◽  
Chee Yoon Yue
Keyword(s):  
Surface Modification ◽  
Microfluidic Devices ◽  
Processing Parameters ◽  
Hot Embossing ◽  
Contact Angle Measurement ◽  
Angle Measurement ◽  
Experimental Conditions ◽  
Water Contact ◽  
Replication Fidelity ◽  
Modified Surface

The fabrication of polymer based microfluidic devices using the hot embossing technique and their surface modification for easy fluid flow through the devices has been a growing field of research. During hot embossing, the replication fidelity on polymer substrate not only depends on the processing parameters such as temperature, pressure and time but also on their chemical structure which affects their thermo-dependent viscoelastic properties. For copolymers such as cyclic olefin copolymer (COC) which comprises ethylene and norbornene units, such properties depend on their relative ethylene and norbornene content. We report in this paper, a systematic study of replication fidelity and surface modification on COC polymer with varying norbornene content from 65 to 82 wt%. Replication fidelity which includes the surface morphology and cross-section profiles of the microchannel were characterized using SEM and Confocal microscope respectively. The modified surface was evaluated using Fourier transform infrared spectroscopy (FTIR spectroscopy) and water contact angle measurement. It was observed that in hot embossing, higher norbornene content contributed to good replication fidelity at identical experimental conditions. Furthermore, it was observed that with increase in norbornene content, the grafting efficiency decreases resulting in poor surface modification.

scholarly journals Effects of Particle Concentration on the Dynamics of a Single-Channel Sewage Pump under Low-Flow-Rate Conditions

2021 ◽  
Vol 17 (5) ◽  
pp. 871-886
Author(s):  
Peijian Zhou ◽  
Chaoshou Yan ◽  
Lingfeng Shu ◽  
Hao Wang ◽  
Jiegang Mou
Keyword(s):  
Flow Rate ◽  
Particle Concentration ◽  
Single Channel ◽  
Low Flow ◽  
Low Flow Rate

scholarly journals Large-Scale Fabrication of Nanostructure on Bio-Metallic Substrate for Surface Enhanced Raman and Fluorescence Scattering

Nanomaterials ◽  
2019 ◽  
Vol 9 (7) ◽  
pp. 916 ◽  
Author(s):  
Lu ◽  
Zhang ◽  
Jiao ◽  
Guan
Keyword(s):  
Large Scale ◽  
Hierarchical Structures ◽  
Metallic Substrate ◽  
Nano Particles ◽  
Fluorescence Signal ◽  
Dual Mode ◽  
Surface Enhanced Fluorescence ◽  
Relative Standard ◽  
Surface Enhanced ◽  
Surface Enhanced Raman

The integration of surface-enhanced Raman scattering (SERS) and surface-enhanced fluorescence (SEF) has attracted increasing interest and is highly probable to improve the sensitivity and reproducibility of spectroscopic investigations in biomedical fields. In this work, dual-mode SERS and SEF hierarchical structures have been developed on a single bio-metallic substrate. The hierarchical structure was composed of micro-grooves, nano-particles, and nano-ripples. The crystal violet was selected as reporter molecule and both the intensity of Raman and fluorescence signals were enhanced because of the dual-mode SERS−SEF phenomena with enhancement factors (EFs) of 7.85 × 105 and 14.32, respectively. The Raman and fluorescence signals also exhibited good uniformity with the relative standard deviation value of 2.46% and 5.15%, respectively. Moreover, the substrate exhibited high sensitivity with the limits of detection (LOD) as low as 1 × 10−11 mol/L using Raman spectroscopy and 1 × 10−10 mol/L by fluorescence spectroscopy. The combined effect of surface plasmon resonance and “hot spots” induced by the hierarchical laser induced periodical surface structures (LIPSS) was mainly contributed to the enhancement of Raman and fluorescence signal. We propose that the integration of SERS and SEF in a single bio-metallic substrate is promising to improve the sensitivity and reproducibility of detection in biomedical investigations.

Visualisation of fluid flow mechanisms through a viscous-porous rock-analogue medium – experiment and model results

2021 ◽  
Author(s):  
Reinier van Noort ◽  
Lawrence Hongliang Wang ◽  
Viktoriya Yarushina
Keyword(s):  
Fluid Flow ◽  
Bulk Viscosity ◽  
Numerical Models ◽  
Digital Camera ◽  
Injection Rate ◽  
Low Flow ◽  
Experimental Conditions ◽  
Deep Earth ◽  
Flow Mechanisms ◽  
Flow Through

<p>Understanding fluid flow patterns in the shallow and deep earth is one of the major challenges of modern earth sciences. Fluid flow may be slow and pervasive, or fast and focused. In the deep earth, focused fluid flow may result in, for example, dikes, veins, volcanic diatremes and gas venting systems. In the shallow Earth, focused fluid flow can be found in the form of fluid escape pipes and gas conducting chimneys, mud volcanoes, sand injectites, pockmarks, hydrothermal vent complexes, etc.</p><p>Focused fluid flow has been reproduced in visco-plastic models of flow through porous materials. However, the mechanisms that cause fluid flow to focus along such relatively narrow channels, with transiently elevated permeability, have not been investigated thoroughly in experiments. We have carried out experiments in a transparent Hele-Shaw cell. In our experiments, a hydrous fluid is injected into an aggregate of viscous grains, and the mechanisms by which this injected fluid flows are recorded using a digital camera. Our experiments demonstrate a dependence of fluid flow mechanisms on the injection rate. At low injection rate, we observe the formation of a slowly-rising diapir. As this diapir slowly rises through the porous medium, it is fed by transient, focused fluid flow following the path of the rising diapir. Once the diapir escapes through the surface of our aggregate, continued fluid flow through the porous aggregate is focused and transient. At high injection rate, instead of a diapir fed by focused fluid flow, an open channel forms as a result of local fluidization of the granular material.</p><p>Our experimental observations are interpreted through visco-plastic models simulating the experimental conditions. These numerical models can reproduce the diapirs observed in our experiments at low flow rate by assuming flow through a layered porous aggregate, with a layer with relatively high bulk viscosity overlying a layer with relatively low bulk viscosity. For low injection rates, such a model reproduces focused fluid flow in the low-viscosity layer, that feeds into a slowly rising diapir in the high-viscosity layer. This model observation thus suggests that the passage of the rising diapir in our experiments leaves a trail, where the aggregate bulk viscosity is lowered and along which ongoing fluid flow can focus transiently.</p>

A Study of the Solids Transport Characteristics in the Non-Newtonian Fluid With Inclined Annulus

2017 ◽  
Author(s):  
Sang-Mok Han ◽  
Nam-Sub Woo ◽  
Young-Ju Kim
Keyword(s):  
Particle Concentration ◽  
Drilling Fluid ◽  
Solid Particles ◽  
Rheological Characteristics ◽  
Pressure Gradients ◽  
Experimental Uncertainty ◽  
Upward Flow ◽  
Experimental Conditions ◽  
Solids Transport ◽  
Pipe Rotation

During drilling, the precipitation velocity of cuttings within an annulus depends on the density, configuration, and size of the cuttings, and on the density, viscosity, and rheological characteristics of the drilling fluid. In this study, in order to identify transfer features of cuttings, an experiment was performed under wide-ranging conditions by constructing a slim hole annulus (44 mm × 30 mm) device. In this experiment, the pressure loss and the particle transport ratio were measured in upward flow of Newtonian and non-Newtonian fluids. These quantities were influenced by particle concentration within the flow, pipe rotation, flow rate, and inclination of the annulus. For both water and CMC (carboxymethylcellulose) solutions, the higher the concentration of the solid particles is, the larger the pressure gradients become. The experimental uncertainty of this study varies from a minimum of 3% to a maximum of 9% depending on the experimental conditions.

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