scholarly journals Versatile Microfluidic Mixing Platform for High- and Low-Viscosity Liquids via Acoustic and Chemical Microbubbles

Micromachines ◽  
2019 ◽  
Vol 10 (12) ◽  
pp. 854
Author(s):  
Yanfang Guan ◽  
Baichuan Sun
Keyword(s):  
Point Of Care ◽  
Mixing Time ◽  
High Viscosity ◽  
Mixing Efficiency ◽  
Chemical Research ◽  
Microfluidic Mixing ◽  
Mixing Effect ◽  
Low Viscosity ◽  
Passive Mixing ◽  
The Relationship

Microfluidic mixers have been extensively studied due to their wide application in various fields, including clinical diagnosis and chemical research. In this paper, we demonstrate a mixing platform that can be used for low- and high-viscosity liquid mixing by integrating passive (utilizing the special circulating crossflow characteristics of a zigzag microstructure and cavitation surfaces at the zigzag corners) and active (adding an acoustic field to produce oscillating microbubbles) mixing methods. By exploring the relationship between the active and passive mixing methods, it was found that the microbubbles were more likely generated at the corners of the zigzag microchannel and achieved the best mixing efficiency with the acoustically generated microbubbles (compared with the straight channel). In addition, a higher mixing effect was achieved when the microchannel corner angle and frequency were 60° and 75 kHz, respectively. Meanwhile, the device also achieved an excellent mixing effect for high-viscosity fluids, such as glycerol (its viscosity was approximately 1000 times that of deionized (DI) water at 25 °C). The mixing time was less than 1 s, and the mixing efficiency was 0.95 in the experiment. Furthermore, a new microbubble generation method was demonstrated based on chemical reactions. A higher mixing efficiency (0.97) was achieved by combining the chemical and acoustic microbubble methods, which provides a new direction for future applications and is suitable for the needs of lab-on-a-chip (LOC) systems and point-of-care testing (POCT).

ESTIMATION OF MIXING EFFICIENCY OF MODEL CONCRETE MIXED IN BI-AXIAL FORCED-MIXING TYPE MIXER BY THE FLUCTUATION OF PRESSURE MEASURED ON THE BLADE

2010 ◽  
Vol 24 (15n16) ◽  
pp. 2496-2501 ◽  
Author(s):  
MOTOAKI YOSHIDA ◽  
CHIKANORI HASHIMOTO ◽  
TAKESHI WATANABE ◽  
HIROYUKI MIZUGUCHI
Keyword(s):  
Axial Rotation ◽  
High Viscosity ◽  
Mixing Efficiency ◽  
Phase System ◽  
Cement Particle ◽  
Efficiency Curve ◽  
Low Viscosity ◽  
Contact Frequency ◽  
Forced Mixing ◽  
Type Mixer

The concrete mixer possesses the basic performance "mixing efficiency", and is one of the most important construction machines on the step that manufactures concrete. The bi-axial forced-mixing type of the mixer is high and the mixing efficiency is the highest. The flow patterns of this type mixer are divided into two: the locally crossing flow and the globally circulating flow. The globally circulating flow uniformly mixes fine particle materials that differ greatly the grain size turned on and are various and cement active. The locally crossing flow contributes to "Knead" to improve the contact frequency of the cement particle and water. In the research, concrete was assumed to be a viscous model of one phase system for the model mixer of two types with different area of the locally crossing flow, the mixing efficiency curve of the model concrete of the high viscosity and the low viscosity was a process of becoming uniform with the axial rotation, and quantification was attempted. The second research tried the quantification of the crossing flow around the blade generated when two circulating flows crossed by the pressure fluctuation of the pressure sensor installed in the surface of the blade of the mixer was attempted, and the magnitude of the crossing Flow generated in the model mixer of two types and the correlation of the mixing efficiency curve were considered.

scholarly journals Microfluidic Magnetic Mixing at Low Reynolds Numbers and in Stagnant Fluids

Micromachines ◽  
2019 ◽  
Vol 10 (11) ◽  
pp. 731 ◽  
Author(s):  
Eriola-Sophia Shanko ◽  
Yoeri van de Burgt ◽  
Patrick D. Anderson ◽  
Jaap M. J. den Toonder
Keyword(s):  
Magnetic Beads ◽  
External Source ◽  
Magnetic Bead ◽  
Mixing Efficiency ◽  
Microfluidic Mixing ◽  
Low Reynolds Number Flows ◽  
Passive Mixing ◽  
Magnetic Mixing ◽  
Low Reynolds ◽  
Active Mixing

Microfluidic mixing becomes a necessity when thorough sample homogenization is required in small volumes of fluid, such as in lab-on-a-chip devices. For example, efficient mixing is extraordinarily challenging in capillary-filling microfluidic devices and in microchambers with stagnant fluids. To address this issue, specifically designed geometrical features can enhance the effect of diffusion and provide efficient mixing by inducing chaotic fluid flow. This scheme is known as “passive” mixing. In addition, when rapid and global mixing is essential, “active” mixing can be applied by exploiting an external source. In particular, magnetic mixing (where a magnetic field acts to stimulate mixing) shows great potential for high mixing efficiency. This method generally involves magnetic beads and external (or integrated) magnets for the creation of chaotic motion in the device. However, there is still plenty of room for exploiting the potential of magnetic beads for mixing applications. Therefore, this review article focuses on the advantages of magnetic bead mixing along with recommendations on improving mixing in low Reynolds number flows (Re ≤ 1) and in stagnant fluids.

Mixing Effect and Energy Efficiency Analysis for Different Lances in Steel Converter Process

2011 ◽  
Vol 317-319 ◽  
pp. 1462-1473
Author(s):  
Dong Xu ◽  
Da Qiang Cang ◽  
Li Xue Qin ◽  
Jian Feng Duan
Keyword(s):  
Energy Efficiency ◽  
Gas Flow ◽  
Mixing Time ◽  
Energy Utilization ◽  
Lance Height ◽  
Utilization Factor ◽  
Mixing Effect ◽  
Steel Converter ◽  
Relationship Of ◽  
The Relationship

The mixing effect in steel converter process is very important to the fluid flow and mass transfer in bath and directly affects the chemical reaction and temperature homogeneity in the industry steel process. The cold model was employed to research the relationship of mixing time, agitation power, lance type, operation parameters, bath shape et al. According to the results, the mixing time of the bath decreases with larger gas flow rate and bigger diameter of the bath. Increasing the nozzle inclination properly is benefit for decreasing the mixing time and improving the agitation of the bath. The relationship of mixing time and lance height is complicated, because the mixing time is fluctuant by the lance rising. By introduce the relative energy utilization factor, the agitation power utilization was analyzed and compared under different conditions. The energy efficiency is higher with larger nozzle inclination as well as the bigger ratio of diameter and depth of the bath.

scholarly journals Effect of meal viscosity and nutrients on satiety, intragastric dilution, and emptying assessed by MRI

2001 ◽  
Vol 280 (6) ◽  
pp. G1227-G1233 ◽  
Author(s):  
Luca Marciani ◽  
Penny A. Gowland ◽  
Robin C. Spiller ◽  
Pretima Manoj ◽  
Rachel J. Moore ◽  
...  
Keyword(s):  
Healthy Subjects ◽  
Delayed Gastric Emptying ◽  
Imaging Techniques ◽  
Nutrient Content ◽  
High Viscosity ◽  
Resonance Imaging ◽  
Low Viscosity ◽  
Magnetic Resonance Imaging Techniques ◽  
The Relationship ◽  
Varying Viscosity

The relationship between the intragastric distribution, dilution, and emptying of meals and satiety was studied using noninvasive magnetic resonance imaging techniques in 12 healthy subjects with four polysaccharide test meals of varying viscosity and nutrient content as follows: 1) low-viscosity nonnutrient, 2) low-viscosity nutrient, 3) high-viscosity nonnutrient, and 4) high-viscosity nutrient. Increasing the nutrient content of the high-viscosity meal delayed gastric emptying from 46 ± 9 to 76 ± 6 min ( P < 0.004), whereas increasing viscosity had a smaller effect. The volume of secretions within the stomach 60 min after ingestion was higher for the high-viscosity nutrient meal ( P < 0.04). A simple model to calculate the total volume of secretion added to the test meal is presented. Color-coded dilution map images showed the heterogeneous process of progressive gastric dilution of high-viscosity meals, whereas low-viscosity meals were uniformly diluted. Fullness was found to be linearly related to total gastric volumes for the nutrient meals ( R 2 = 0.98) and logarithmically related for the nonnutrient meals ( R 2 = 0.96). Fullness was higher for high- compared with low-viscosity meals ( P < 0.02), and with the nutrient meals this was associated with greater antral volumes ( P < 0.05).

scholarly journals Effect of viscosity of a liquid membrane containing oleyl alcohol on the pertraction of butyric acid

2013 ◽  
Vol 67 (12) ◽  
Author(s):  
Marek Blahušiak ◽  
Ján Marták ◽  
Fernando Miranda ◽  
Štefan Schlosser ◽  
José Teixeira
Keyword(s):  
Mass Transfer ◽  
Butyric Acid ◽  
Driving Force ◽  
Oleyl Alcohol ◽  
Liquid Membrane ◽  
High Viscosity ◽  
Membrane Extraction ◽  
Low Viscosity ◽  
Supported Liquid Membranes ◽  
The Relationship

AbstractSolvent formulation is important in the optimization of the mass-transfer through supported liquid membranes (SLM) in pertraction and membrane extraction. Oleyl alcohol (OA) is frequently used as the solvent or diluent in the extraction of carboxylic acids. A disadvantage of OA is its relatively high viscosity of 28.32 mPa s at 25°C. This can be decreased by the application of a less viscous OA diluent, e.g. dodecane. The relationship between the ratio of the distribution coefficient of butyric acid (BA), D F, and the viscosity of OA-dodecane solvents, µ, as extraction and transport characteristics, and the overall mass-transfer coefficient, K p, through SLMs was analyzed. Dependence of the D F/µ ratio on the OA concentration showed a maximum at the OA concentration of 15 mass % to 30 mass %. The OA concentration dependence of K p for SLMs exhibited also a maximum at about 30 mass % and 20 mass % of OA at the BA concentration driving force of 0.12 kmol m−3 and 0.3 kmol m−3, respectively. Shifting of the maximum in K p dependences towards lower OA concentrations by increasing the BA concentration driving force is in agreement with the D F/µ ratio dependence. Using pure OA as the solvent or diluent is not preferable and a mixture of a low viscosity diluent with the OA concentration below 40 mass % should be used. The presented results show the potential of the D F/µ ratio in the screening and formulation of solvents in extraction and SLM optimization.

scholarly journals A Low-Viscosity BisGMA Derivative for Resin Composites: Synthesis, Characterization, and Evaluation of Its Rheological Properties

Materials ◽  
2021 ◽  
Vol 14 (2) ◽  
pp. 338
Author(s):  
Ali Alrahlah ◽  
Abdel-Basit Al-Odayni ◽  
Haifa Fahad Al-Mutairi ◽  
Bashaer Mousa Almousa ◽  
Faisal S. Alsubaie ◽  
...  
Keyword(s):  
Substantial Reduction ◽  
Triethylene Glycol ◽  
High Viscosity ◽  
Resin Matrix ◽  
Resonance Spectroscopy ◽  
Dental Resin ◽  
Triethylene Glycol Dimethacrylate ◽  
Oh Groups ◽  
Low Viscosity ◽  
13C Nuclear Magnetic Resonance

This study aimed to synthesize new bisphenol A-glycidyl methacrylate (BisGMA) derivatives, targeting a reduction in its viscosity by substituting one of its OH groups, the leading cause of its high viscosity, with a chlorine atom. Hence, this monochloro-BisGMA (mCl-BisGMA) monomer was synthesized by Appel reaction procedure, and its structure was confirmed using Fourier transform infrared spectroscopy, 1H and 13C-nuclear magnetic resonance spectroscopy, and mass spectroscopy. The viscosity of mCl-BisGMA (8.3 Pa·s) was measured under rheometry conditions, and it was found to be more than 65-fold lower than that of BisGMA (566.1 Pa·s) at 25 °C. For the assessment of the viscosity changes of model resins in the presence of mCl-BisGMA, a series of resin matrices, in which, besides BisGMA, 50 wt % was triethylene glycol dimethacrylate, were prepared and evaluated at 20, 25, and 35 °C. Thus, BisGMA was incrementally replaced by 25% mCl-BisGMA to obtain TBC0, TBC25, TBC50, TBC75, and TBC100 blends. The viscosity decreased with temperature, and the mCl-BisGMA content in the resin mixture increased. The substantial reduction in the viscosity value of mCl-BisGMA compared with that of BisGMA may imply its potential use as a dental resin matrix, either alone or in combination with traditional monomers. However, the various properties of mCl-BisGMA-containing matrices should be evaluated.

scholarly journals A Conceptional Approach of Resin-Transfer-Molding to Rosin-Sourced Epoxy Matrix Green Composites

Aerospace ◽  
2020 ◽  
Vol 8 (1) ◽  
pp. 5
Author(s):  
Sicong Yu ◽  
Xufeng Zhang ◽  
Xiaoling Liu ◽  
Chris Rudd ◽  
Xiaosu Yi
Keyword(s):  
Composite Laminates ◽  
Resin Transfer Molding ◽  
High Viscosity ◽  
Ramie Fiber ◽  
Liquid Composite Molding ◽  
Curing Agent ◽  
Molding Process ◽  
Transfer Molding ◽  
Low Viscosity ◽  
Composite Molding

In this concept-proof study, a preform-based RTM (Resin Transfer Molding) process is presented that is characterized by first pre-loading the solid curing agent onto the preform, and then injecting the liquid nonreactive resin with an intrinsically low viscosity into the mold to infiltrate and wet the pre-loaded preform. The separation of resin and hardener helped to process inherently high viscosity resins in a convenient way. Rosin-sourced, anhydrite-cured epoxies that would normally be regarded as unsuited to liquid composite molding, were thus processed. Rheological tests revealed that by separating the anhydrite curing agent from a formulated RTM resin system, the remaining epoxy liquid had its flowtime extended. C-scan and glass transition temperature tests showed that the preform pre-loaded with anhydrite was fully infiltrated and wetted by the liquid epoxy, and the two components were diffused and dissolved with each other, and finally, well reacted and cured. Composite laminates made via this approach exhibited roughly comparable quality and mechanical properties with prepreg controls via autoclave or compression molding, respectively. These findings were verified for both carbon and ramie fiber composites.

scholarly journals Simple empirical method for estimating lava-effusion rate using nighttime Himawari-8 1.6-µm infrared images

2021 ◽  
Vol 73 (1) ◽  
Author(s):  
Takayuki Kaneko ◽  
Atsushi Yasuda ◽  
Toshitsugu Fujii
Keyword(s):  
Lava Flow ◽  
Estimation Method ◽  
Simulation Software ◽  
Spectral Radiance ◽  
Effusion Rate ◽  
Actual Distribution ◽  
High Positive Correlation ◽  
Low Viscosity ◽  
Lava Effusion ◽  
The Relationship

AbstractThe effusion rate of lava is one of the most important eruption parameters, as it is closely related to the migration process of magma underground and on the surface, such as changes in lava flow direction or formation of new effusing vents. Establishment of a continuous and rapid estimation method has been an issue in volcano research as well as disaster prevention planning. For effusive eruptions of low-viscosity lava, we examined the relationship between the nighttime spectral radiance in the 1.6-µm band of the Himawari-8 satellite (R1.6Mx: the pixel value showing the maximum radiance in the heat source area) and the effusion rate using data from the 2017 Nishinoshima activity. Our analysis confirmed that there was a high positive correlation between these two parameters. Based on the linear-regression equation obtained here (Y = 0.47X, where Y is an effusion rate of 106 m3 day−1 and X is an R1.6Mx of 106 W m−2 sr−1 m−1), we can estimate the lava-effusion rate from the observation data of Himawari-8 via a simple calculation. Data from the 2015 Raung activity—an effusive eruption of low-viscosity lava—were arranged along the extension of this regression line, which suggests that the relationship is applicable up to a level of ~ 2 × 106 m3 day−1. We applied this method to the December 2019 Nishinoshima activity and obtained an effusion rate of 0.50 × 106 m3 day−1 for the initial stage. We also calculated the effusion rate for the same period based on a topographic method, and verified that the obtained value, 0.48 × 106 m3 day−1, agreed with the estimation using the Himawari-8 data. Further, for Nishinoshima, we simulated the extent of hazard areas from the initial lava flow and compared cases using the effusion rate obtained here and the value corresponding to the average effusion rate for the 2013–2015 eruptions. The former distribution was close to the actual distribution, while the latter was much smaller. By combining this effusion-rate estimation method with real-time observations by Himawari-8 and lava-flow simulation software, we can build a rapid and precise prediction system for volcano hazard areas.

Electrochemical Evaluation for Rust Preventive Properties of Rust Preventive Oils Coated on Fe-Cu-C Sintered Steel

2014 ◽  
Vol 783-786 ◽  
pp. 2537-2540 ◽  
Author(s):  
Satoshi Sunada ◽  
Norio Nunomura ◽  
Sayaka Hirata ◽  
Naoki Nagase
Keyword(s):  
Open Circuit Potential ◽  
High Viscosity ◽  
Open Circuit ◽  
Second Step ◽  
Sintered Steel ◽  
Corrosive Solution ◽  
The Third ◽  
Low Viscosity ◽  
Sintered Steels ◽  
Electrochemical Evaluation

Since Fe-Cu-C sintered steels are easily rusted, they are coated with rust preventive oils. High viscosity of those rust preventive oils decrease workability, and low viscosity deteriorates rust preventive performance. Therefore, it is necessary to develop new rust preventive oils with contradictory properties of low viscosity and superior rust prevention. However, precise methodology to evaluate rust prevention ability has not been established. In this study, we developed new technique to quantitatively evaluate rust prevention ability by measuring the open circuit potential through thin corrosive solution on Fe-Cu-C sintered steels coated with a rust preventive oils. As a result, the ability for rust prevention can be measured quantitatively, and it decreases slowly over time, with repeating destruction and restoration. Furthermore, it was found that the deteriorating processes of rust prevention ability for rust prevention oils are composed of three characteristics steps respectively. That is, in the first step the great open circuit potential changes from 0V to-0.3V with repetition were observed where the excellent rust prevention ability was kept, in the second step it decreases slowly from-0.1V to-0.4V with oscillation of the small potential changes where the gradual decrease of rust prevention ability was recognized and in the third step it decreases monotonously in the lower potential than-0.4V where the rust was observed because of the remarkable deteriorating of the rust prevention ability.

scholarly journals Countrywide survey on utilization of medical devices by GPs in Hungary: advantages of the cluster-practice model

2021 ◽  
Vol 22 ◽  
Author(s):  
Katalin Dózsa ◽  
Fruzsina Mezei ◽  
Tamás Tóth ◽  
Ábel Perjés ◽  
Péter Pollner
Keyword(s):  
Medical Devices ◽  
Point Of Care ◽  
Daily Practice ◽  
Evidence Based ◽  
Self Assessment ◽  
Practice Model ◽  
Practice Models ◽  
Integrate State ◽  
The Relationship ◽  
Further Development

Abstract Background: Expectations towards general practitioners (GPs) are continuously increasing to provide a more systematic preventive- and definitive-based care, a wider range of multidisciplinary team-based services and to integrate state-of-the-art digital solutions into daily practice. Aided by development programmes, Hungarian primary care is facing the challenge to fulfil its role as the provider of comprehensive, high quality, patient-centred, preventive care, answering the challenges caused by non-communicable diseases (NCDs). Aim: The article aims to provide an insight into the utilization of simple, digital, medical devices. We show the relationship between the primary health care (PHC) practice models and the used types of devices. We point at further development directions of GP practices regarding the utilization of evidence-based medical technologies and how such devices support the screening and chronic care of patients with NCDs in everyday practice. Methods: Data were collected using an online self-assessment questionnaire from 1800 Hungarian GPs registered in Hungary. Descriptive statistics, Wilcoxon’s test and χ2 test were applied to analyze the ownership and utilization of 32 types of medical devices, characteristics of the GP practices and to highlight the differences between traditional and cluster-based operating model. Findings: Based on the responses from 27.7% of all Hungarian GPs, the medical device infrastructure was found to be limited especially in single GP-practices. Those involved in development projects of GP’s clusters in the last decade reported a wider range and significantly more intensive utilization of evidence-based technologies (average number of devices: 5.42 versus 7.56, P<.001), but even these GPs are not using some of their devices (e.g., various point of care testing devices) due to the lack of financing. In addition, GPs involved in GPs-cluster development model programmes showed significantly greater willingness for sharing relatively expensive, extra workforce-demanding technologies (χ2 = 24.5, P<.001).

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