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centrifugal
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Chlorophyll-based wicking sensing bioplatform coupled with a smartphone-based sample-to-answer analytical device for on-site detection of picric acid
, Article Biosensors and Bioelectronics: X ; Volume 11 , 2022 ; 25901370 (ISSN) ; Abbasi Moayed, S ; Hamzei, Z ; Keshavarz, A ; Yousefi, S ; Hormozi Nezhad, M. R ; Golmohammadi, H ; Sharif University of Technology
Elsevier Ltd
2022
Abstract
The development of inexpensive, equipment-free, portable, and user/environmentally-friendly analytical devices that can be efficiently utilized for on-site detection of PA is still a great challenge. To address these unmet demands, we have developed a smartphone-based disposable sensing bioplatform through immobilization of chlorophyll in a cotton thread for fluorescent monitoring of picric acid (PA). The fluorescence quenching of chlorophyll upon increasing the PA concentration based on the inner filter effect was considered as the sensing strategy in the developed sensor. The fabricated thread-based microfluidic sensing bioplatform was further coupled with a compact, low cost, portable,...
Nanofluid preparation, stability and performance for CO2 absorption and desorption enhancement: A review
, Article Journal of Environmental Management ; Volume 313 , 2022 ; 03014797 (ISSN) ; Rahimi, K ; Saghandali, F ; Scott, J ; Lovell, E ; Sharif University of Technology
Academic Press
2022
Abstract
In recent years, the importance of capturing CO2 has increased due to the necessity of minimizing climate change and the detrimental effects of CO2 emissions from industrial processes. CO2 absorption, as one of the most mature carbon capture technologies, has been improved by introducing nanosized particles into liquid absorbents. Nanofluids have been the subject of interest in many studies recently due to their tremendous impact on absorption. This review comprehensively examines the CO2 absorption behavior for nanofluids through the investigation of different absorption systems. Potential mechanisms for improving the absorption/regeneration performance of nanoabsorbents as well as the...
Green synthesis of PEG-coated MIL-100(Fe) for controlled release of dacarbazine and its anticancer potential against human melanoma cells
, Article International Journal of Pharmaceutics ; Volume 618 , 2022 ; 03785173 (ISSN) ; Vossoughi, M ; Bagherzadeh, M ; Pooshang Bagheri, K ; Sharif University of Technology
Elsevier B.V
2022
Abstract
In this study, the potential of using MIL-100(Fe) metal–organic framework (MOF) for loading and controlling the release of dacarbazine (DTIC) was evaluated for in vitro treatment of melanoma. The drug loading was performed during the green synthesis of MIL-100(Fe) in an aqueous media without using any harmful solvents, to obtain MIL-DTIC. The surface of this structure was then coated with polyethylene glycol (PEG) in the same aqueous solution to synthesize MIL-DTIC-PEG. The synthesized samples were characterized using various methods. Their release profile was studied in phosphate-buffered saline (PBS) and simulated cutaneous medium (SCM). The cytotoxicity of DTIC and its nano-MOF...
The influence of the female reproductive tract and sperm features on the design of microfluidic sperm-sorting devices
, Article Journal of Assisted Reproduction and Genetics ; Volume 39, Issue 1 , 2022 , Pages 19-36 ; 10580468 (ISSN) ; Hosseini, M ; Saadatmand, M ; Abbaspourrad, A ; Sharif University of Technology
Springer
2022
Abstract
Although medical advancements have successfully helped a lot of couples with their infertility by assisted reproductive technologies (ART), sperm selection, a crucial stage in ART, has remained challenging. Therefore, we aimed to investigate novel sperm separation methods, specifically microfluidic systems, as they do sperm selection based on sperm and/or the female reproductive tract (FRT) features without inflicting any damage to the selected sperm during the process. In this review, after an exhaustive studying of FRT features, which can implement by microfluidics devices, the focus was centered on sperm selection and investigation devices. During this study, we tried not to only point to...
Performance improvement of mixed-flow centrifugal pumps with new impeller shrouds: Numerical and experimental investigations
, Article Renewable Energy ; Volume 163 , 2021 , Pages 635-648 ; 09601481 (ISSN) ; Khalesi, J ; Jafari, M ; Gazori, H. O ; Sharif University of Technology
Elsevier Ltd
2021
Abstract
A new impeller configuration with innovatively-designed shrouds is introduced, and its impact on the pressure head and efficiency of the semi-open centrifugal pump is explored using experimental and numerical approaches. The proposed design includes attaching specific plates called bladelets to a semi-open impeller to limit the secondary flows over the blades resulting in an increase in the pump head and efficiency. Hydraulic performance of a centrifugal pump with three different bladelets at angles of 30°, 60°, and 90° is investigated experimentally, and the results are compared to semi-open and closed impellers. The values of pressure head and efficiency of the proposed centrifugal pump...
A new detection chamber design on centrifugal microfluidic platform to measure hemoglobin of whole blood
, Article SLAS Technology ; Volume 26, Issue 4 , 2021 , Pages 392-398 ; 24726303 (ISSN) ; Saadatmand, M ; Eghbal, M ; Bakhtiari, M. R ; Mehraji, S ; Sharif University of Technology
SAGE Publications Inc
2021
Abstract
Undoubtedly, microfluidics has been a focal point of interdisciplinary science during the last two decades, resulting in many developments in this area. Centrifugal microfluidic platforms have good potential for use in point-of-care devices because they take advantage of some intrinsic forces, most notably centrifugal force, which obviates the need to any external driving forces. Herein, we introduce a newly designed detection chamber for use on microfluidic discs that can be employed as an absorbance readout step in cases where the final solution has a very low viscosity and surface tension. In such situations, our chamber easily eliminates the air bubbles from the final solution without...
High-throughput, label-free isolation of white blood cells from whole blood using parallel spiral microchannels with u-shaped cross-section
, Article Biosensors ; Volume 11, Issue 11 , 2021 ; 20796374 (ISSN) ; Rostami, P ; Saidi, M. S ; Firoozabadi, B ; Kashaninejad, N ; Sharif University of Technology
MDPI
2021
Abstract
Rapid isolation of white blood cells (WBCs) from whole blood is an essential part of any WBC examination platform. However, most conventional cell separation techniques are labor-intensive and low throughput, require large volumes of samples, need extensive cell manipulation, and have low purity. To address these challenges, we report the design and fabrication of a passive, label-free microfluidic device with a unique U-shaped cross-section to separate WBCs from whole blood using hydrodynamic forces that exist in a microchannel with curvilinear geometry. It is shown that the spiral microchannel with a U-shaped cross-section concentrates larger blood cells (e.g., WBCs) in the inner...
Performance of elevated energy pile groups with different pile spacing in clay subjected to cyclic non-symmetrical thermal loading
, Article Renewable Energy ; Volume 172 , 2021 , Pages 998-1012 ; 09601481 (ISSN) ; Farivar, A ; Gomaa, S. M. M. H ; Shakeel, M ; Jafarzadeh, F ; Sharif University of Technology
Elsevier Ltd
2021
Abstract
There is an increasing interest and use of energy foundation worldwide. Full-scale tests, physical model tests at one Earth's gravity and at elevated gravity in a geotechnical centrifuge and numerical simulations have been widely reported in the literature. Almost all studies have focused on single energy piles (EPs) and pile groups subjected to symmetrical thermal loads, although it is not unusual to have energy pile groups stressed by non-symmetrical thermal loads. In this study, a series of non-symmetrical thermal loading centrifuge model tests were conducted in saturated soft clay (OCR = 1.7), which is much vulnerable to temperature changes. The tests aim to investigate the effects of...
Theoretical and experimental investigation of design parameter effects on the slip phenomenon and performance of a centrifugal compressor
, Article Scientia Iranica ; Volume 28, Issue 1 , 2021 , Pages 291-304 ; 10263098 (ISSN) ; Hajilouy Benisi, A ; Manzari, M. T ; Sharif University of Technology
Sharif University of Technology
2021
Abstract
Numerous studies have investigated driving equations used to predict the slip factor in centrifugal compressors so far. Inevitably, through these studies, the ow field characteristics have been simplified and the effects of the related parameters have been neglected. The present study, experimentally and numerically, investigates the slip phenomenon in a specific centrifugal compressor with complex blade curves and splitter blades, considering the main effective parameters such as the number of blades, exit angle, etc. To this end, a three-dimensional simulation of the viscous flow field of the compressor via an appropriate turbulence method was performed. In addition, an experimental study...
Dna-Rna hybrid (R-loop): From a unified picture of the mammalian telomere to the genome-wide profile
, Article Cells ; Volume 10, Issue 6 , 2021 ; 20734409 (ISSN) ; Sharifi Zarchi, A ; Kianmehr, L ; Sharif University of Technology
MDPI
2021
Abstract
Local three-stranded DNA/RNA hybrid regions of genomes (R-loops) have been detected either by binding of a monoclonal antibody (DRIP assay) or by enzymatic recognition by RNaseH. Such a structure has been postulated for mouse and human telomeres, clearly suggested by the identification of the complementary RNA Telomeric repeat-containing RNA “TERRA”. However, the tremendous disparity in the information obtained with antibody-based technology drove us to investigate a new strategy. Based on the observation that DNA/RNA hybrids in a triplex complex genome co-purify with the double-stranded chromosomal DNA fraction, we developed a direct preparative approach from total protein-free cellular...
Numerical study of stiff diaphragm walls used to improve the performance of rocking foundation systems
, Article Journal of Earthquake Engineering ; Volume 25, Issue 13 , 2021 , Pages 2628-2650 ; 13632469 (ISSN) ; Fadaee, M ; Ghannad, M. A ; Jahankhah, H ; Sharif University of Technology
Taylor and Francis Ltd
2021
Abstract
This research explores the effectiveness of the use of stiff diaphragm walls next to a rocking foundation through numerical simulation. This improvement technique is used as a means to increase in subsoil peripheral confinement and reduce rocking-induced settlement. The numerical model was verified by the centrifuge test of rocking shallow foundations on clay under cyclic loading. A parametric study was conducted to explore the effect of three stiff wall shapes on the performance of a rocking system. The general conclusion of the parametric investigation is that the use of stiff diaphragm walls reduced the sinking-dominated settlement response of the rocking system. © 2019 Taylor & Francis...
Evaluation of variable permeability model in simulation of seismic behavior of uniform level and gently sloping sand layers
, Article Earth Sciences Research Journal ; Volume 24, Issue 3 , 2020 , Pages 328-336 ; Seyfi, S ; Shahir, H ; Sharif University of Technology
Universidad Nacional de Colombia
2020
Abstract
In this study, a fully coupled dynamic finite element model was employed for numerical simulation of the response of level to gently sloping saturated sand layers subjected to cyclic loading. This model utilized a critical state two-surface-plasticity constitutive model to simulate the cyclic behavior of sandy soil. Moreover, a recently proposed variable permeability function was implemented in the numerical model to reflect the effects of soil permeability variations during the liquefaction phenomenon. The numerical model was validated by simulating a number of well-documented geotechnical centrifuge tests with different relative density of sand, base acceleration time history, and surface...
Modeling and simulation of flow and uranium isotopes separation in gas centrifuges using implicit coupled density-based solver in OpenFOAM
, Article European Journal of Computational Mechanics ; Volume 29, Issue 1 , 2020 , Pages 1-26 ; Salehi, A. A ; Keshtkar, A. R ; Shadman, M. M ; Askari, M. H ; Sharif University of Technology
River Publishers
2020
Abstract
The performance of a gas centrifuge that is used for isotopes separation is dependent on the gas flow inside it. In this study, for modeling the UF6 gas flow, an Implicit Coupled Density-Based (ICDB) solver, was developed in OpenFOAM. To validate the ICDB solver, the gas flow within the rotor in total reflux state was compared with the analytical solution obtained by Onsager model and the numerical solution obtained by the Fluent software. The results showed that the ICDB solver had acceptable accuracy and validity. Also the computational efficiency of Roe, AUSM (Advection Upstream Splitting Method) and AUSM+ up schemes were compared. The results showed AUSM+ up scheme is efficient. Then,...
Investigation of the continuum-rarefied flow and isotope separation using a hybrid CFD-DSMC simulation for UF6 in a gas centrifuge
, Article Annals of Nuclear Energy ; 2020 ; Akbar Salehi, A ; Reza Keshtkar, A ; Mahdi Shadman, M ; Hossein Askari, M ; Sharif University of Technology
Elsevier Ltd
2020
Abstract
UF6 gas flow in the total regions of a rotor with the radius of 0.1 m and the length of 1 m in axisymmetric and steady states was simulated using a new hybrid CFD-DSMC method in the OpenFOAM framework. Implicit coupled density-based scheme was performed for CFD method, and Variable Hard Sphere (VHS) and diffuse model were employed in DSMC method. Also, as an initial estimation, the local Knudsen number was applied to determine the interface location between the continuum-rarefied regions (r = 0.0855 m). Then it was modified (r = 0.084 m) to reduce the computational cost. The comparison results of pure CFD and CFD-DSMC methods illustrated that there were large differences between the flow...
Design and simulation of an integrated centrifugal microfluidic device for CTCs separation and cell lysis
, Article Micromachines ; Volume 11, Issue 7 , July , 2020 ; Shamloo, A ; Akbari, J ; Tebon, P ; Dokmeci, M. R ; Ahadian, S ; Sharif University of Technology
MDPI AG
2020
Abstract
Separation of circulating tumor cells (CTCs) from blood samples and subsequent DNA extraction from these cells play a crucial role in cancer research and drug discovery. Microfluidics is a versatile technology that has been applied to create niche solutions to biomedical applications, such as cell separation and mixing, droplet generation, bioprinting, and organs on a chip. Centrifugal microfluidic biochips created on compact disks show great potential in processing biological samples for point of care diagnostics. This study investigates the design and numerical simulation of an integrated microfluidic device, including a cell separation unit for isolating CTCs from a blood sample and a...
Fluidic barriers in droplet-based centrifugal microfluidics: Generation of multiple emulsions and microspheres
, Article Sensors and Actuators, B: Chemical ; Volume 311 , May , 2020 ; Madou, M. J ; Dorri Nokoorani, Y ; Shamloo, A ; Martinez Chapa, S. O ; Sharif University of Technology
Elsevier B. V
2020
Abstract
Droplet generation is very important in biochemical processes such as cell encapsulation, digital PCR (Polymerase Chain Reaction), and drug delivery. In the present paper, a density-based method called “fluidic barrier” is introduced to produce multiple emulsions on a centrifugal microfluidic platform or Lab-on-a-CD (LOCD). We show that the density and the viscosity of the fluids involved are important parameters for predicting the characteristics of the droplets generated with this method. Moreover, we broadened this concept by using the fluidic barriers to separate reactive chemicals. As a proof of concept, alginate and CaCl2 solutions are separated by an oil barrier to control the...
Numerical simulation of mixing and heat transfer in an integrated centrifugal microfluidic system for nested-PCR amplification and gene detection
, Article Sensors and Actuators, B: Chemical ; Volume 283 , 2019 , Pages 831-841 ; 09254005 (ISSN) ; Ghazimirsaeed, E ; Shamloo, A ; Sharif University of Technology
Elsevier B.V
2019
Abstract
Nucleic acid amplification via polymerase chain reaction (PCR) is one of the essential and powerful methods used in a myriad of bio-assays in clinical laboratories. Application of microfluidic devices in biologically-related processes like PCR can result in the usage of less volume of reactant samples and reduce the processing time. By implementing PCR systems on centrifugal microfluidic platforms, automation and portability can be easily achieved. Although several methods have been developed, most of them are still dealing with challenges of the required high processing time. This study presents the numerical simulation of a fully automated PCR system with the goal of enhancing the mixing...
Prediction of erosive wear locations in centrifugal compressor using CFD simulation and comparison with experimental model
, Article Journal of the Brazilian Society of Mechanical Sciences and Engineering ; Volume 41, Issue 2 , 2019 ; 16785878 (ISSN) ; MomeniLarimi, M ; Ganji, B ; Ranjbar, A ; Sharif University of Technology
Springer Verlag
2019
Abstract
Erosive wear is one of the efficiency reduction causes in centrifugal compressors. The presence of suspended solid particles in the fluid causes deformations in different parts of the compressor, especially blades of the impeller. Therefore, erosion not only decreases the part lifetime by destruction of blades form, but also increases energy losses. For this reason, specifying the erosion locations and choosing a suitable material have an important effect on optimum functionality of the machine. In this paper, erosion locations of a compressor impeller by using computational fluid dynamics (CFD) in high temperature and pressure are attained and compared with experimental model. The...
Design and fabrication of a centrifugal microfluidic disc including septum valve for measuring hemoglobin A1c in human whole blood using immunoturbidimetry method
, Article Talanta ; Volume 190 , 2018 , Pages 134-139 ; 00399140 (ISSN) ; Saadatmand, M ; Bakhtiari, M. R ; Eghbal, M ; Sharif University of Technology
Elsevier B.V
2018
Abstract
Diabetes mellitus is a global endemic with a rapidly increasing prevalence in both developing and developed countries. Recently, hemoglobin A1c has been recommended by the American Diabetes Associations as a possible substitute for fasting blood glucose for the diagnosis of diabetes, because it is an indicator of long-term glycemic control. Also, centrifugal microfluidic systems have good potential for use in the point of care testing systems. In this study, a centrifugal microfluidic disc was designed and manufactured to measure hemoglobin A1c in whole blood using an immunoturbidimetry based method. Also, a new passive valve, named septum valve, was presented to precisely control the entry...
Newtonian and generalized Newtonian reacting flows in serpentine microchannels: pressure driven and centrifugal microfluidics
, Article Journal of Non-Newtonian Fluid Mechanics ; Volume 251 , January , 2018 , Pages 88-96 ; 03770257 (ISSN) ; Shamloo, A ; Sharif University of Technology
Elsevier B.V
2018
Abstract
This paper presents a comprehensive 3D numerical simulation of reacting flows in micro scale dimension through centrifugal, or Lab-On-a-CD (LOCD), and pressure-driven, or Lab-On-a-Chip (LOC) devices. Three different serpentine channel configurations (rectangular, triangular and sinusoidal) are investigated. In these configurations, two chemical species enter from two inlets and according to an irreversible chemical reaction, start yielding other species. Both Newtonian and generalized Newtonian fluids are considered in the simulations and the results are compared for both LOC and LOCD devices. Besides, the effects of different parameters such as the aspect ratio of channels’ cross section,...