| 1. |
- Park, Seung Hyun, et al.
(author)
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Nonpharmaceutical interventions reduce the incidence and mortality of COVID-19: A study based on the survey from the International COVID-19 Research Network (ICRN)
- 2023
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In: Journal of Medical Virology. - : WILEY. - 0146-6615 .- 1096-9071. ; 95:2
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Journal article (peer-reviewed)abstract
- The recently emerged novel coronavirus, "severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2)," caused a highly contagious disease called coronavirus disease 2019 (COVID-19). It has severely damaged the worlds most developed countries and has turned into a major threat for low- and middle-income countries. Since its emergence in late 2019, medical interventions have been substantial, and most countries relied on public health measures collectively known as nonpharmaceutical interventions (NPIs). We aimed to centralize the accumulative knowledge of NPIs against COVID-19 for each country under one worldwide consortium. International COVID-19 Research Network collaborators developed a cross-sectional online survey to assess the implications of NPIs and sanitary supply on the incidence and mortality of COVID-19. The survey was conducted between January 1 and February 1, 2021, and participants from 92 countries/territories completed it. The association between NPIs, sanitation supplies, and incidence and mortality were examined by multivariate regression, with the log-transformed value of population as an offset value. The majority of countries/territories applied several preventive strategies, including social distancing (100.0%), quarantine (100.0%), isolation (98.9%), and school closure (97.8%). Individual-level preventive measures such as personal hygiene (100.0%) and wearing facial masks (94.6% at hospitals; 93.5% at mass transportation; 91.3% in mass gathering facilities) were also frequently applied. Quarantine at a designated place was negatively associated with incidence and mortality compared to home quarantine. Isolation at a designated place was also associated with reduced mortality compared to home isolation. Recommendations to use sanitizer for personal hygiene reduced incidence compared to the recommendation to use soap. Deprivation of masks was associated with increased incidence. Higher incidence and mortality were found in countries/territories with higher economic levels. Mask deprivation was pervasive regardless of economic level. NPIs against COVID-19 such as using sanitizer, quarantine, and isolation can decrease the incidence and mortality of COVID-19.
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| 2. |
- Gevari, Moein Talebian, et al.
(author)
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Engineered Lateral Roughness Element Implementation and Working Fluid Alteration to Intensify Hydrodynamic Cavitating Flows on a Chip for Energy Harvesting
- 2020
-
In: Micromachines. - : MDPI. - 2072-666X. ; 11:1
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Journal article (peer-reviewed)abstract
- Hydrodynamic cavitation is considered an effective tool to be used in different applications, such as surface cleaning, ones in the food industry, energy harvesting, water treatment, biomedical applications, and heat transfer enhancement. Thus, both characterization and intensification of cavitation phenomenon are of great importance. This study involves design and optimization of cavitation on chip devices by utilizing wall roughness elements and working fluid alteration. Seven different microfluidic devices were fabricated and tested. In order to harvest more energy from cavitating flows, different roughness elements were used to decrease the inlet pressure (input to the system), at which cavitation inception occurs. The implemented wall roughness elements were engineered structures in the shape of equilateral triangles embedded in the design of the microfluidic devices. The cavitation phenomena were also studied using ethanol as the working fluid, so that the fluid behavior differences in the tested cavitation on chip devices were explained and compared. The employment of the wall roughness elements was an effective approach to optimize the performances of the devices. The experimental results exhibited entirely different flow patterns for ethanol compared to water, which suggests the dominant effect of the surface tension on hydrodynamic cavitation in microfluidic channels.
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| 3. |
- Shafaghi, Ali Hosseinpour, et al.
(author)
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On cavitation inception and cavitating flow patterns in a multi-orifice microfluidic device with a functional surface
- 2021
-
In: Physics of fluids. - : AMER INST PHYSICS. - 1070-6631 .- 1089-7666. ; 33:3
-
Journal article (peer-reviewed)abstract
- During the last decade, hydrodynamic cavitation has been implemented in various applications such as energy harvesting and biomedical applications. Facile hydrodynamic cavitation methods are required for fulfilling the requirements in these applications. In this study, a new generation microfluidic device containing eight parallel micro-orifices with a new design was fabricated and tested with the purpose of intensifying the cavitating flows and early cavitation inception. The roughness elements in the micro-orifices facilitated cavitation inception. This study presents a general perspective of occurrence of different cavitating flow patterns in microscale and addresses the ambiguities about the conditions for the formation of a specific flow pattern. Cavitation inception occurred with the appearance of small bubbles emerging from roughness elements at a rather low upstream pressure in the open loop experimental setup. A reduction in the cavitation number resulted in the formation of different flow patterns such as cavitation clouds, twin cavities, sheet cavities, and bubbly flows. Having several flow patterns with different intensities all together within a single microfluidic device is the main advantage of the proposed device over the state of the art microfluidic devices. Generation of flow patterns with various released energy levels makes this proposed device a unique multi-functional platform, which can be implemented to a lab on a chip platform for applications such as nanoparticle synthesis and wound healing.
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| 4. |
- Shafaghi, Ali Hosseinpour, et al.
(author)
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On the Effect of the Respiratory Droplet Generation Condition on COVID-19 Transmission
- 2020
-
In: Fluids. - : MDPI. - 2311-5521. ; 5:3
-
Journal article (peer-reviewed)abstract
- Coronavirus (COVID-19) is a highly infectious viral disease and first appeared in Wuhan, China. Within a short time, it has become a global health issue. The sudden emergence of COVID-19 has been accompanied by numerous uncertainties about its impact in many perspectives. One of major challenges is understanding the underlying mechanisms in the spread of this outbreak. COVID-19 is spread similar to the majority of infectious diseases through transmission via relatively large respiratory droplets. The awareness of the dispersal of these droplets is crucial in not only improving methods for controlling the dispersion of COVID-19 droplets, but also in discovering fundamental mechanisms of its transmission. In this study, a numerical model is developed to study the motion of droplets expelled through the respiratory system. Based on the source of these droplets, different sizes of droplets such as large ones and aerosols, which behave differently in the environment, can be generated. In this regard, diverse sources of droplets, namely breathing, coughing, and sneezing, are considered in this analysis. Besides, the time for a single droplet to fall from a height of 1.8 m is also obtained. The results reveal that the traditional distances suggested by different sources for keeping the social distance are not enough, which is linked to different nature of the droplet generation.
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| 5. |
- Abbasiasl, Taher, et al.
(author)
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A Flexible Cystoscope Based on Hydrodynamic Cavitation for Tumor Tissue Ablation
- 2022
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In: IEEE Transactions on Biomedical Engineering. - : Institute of Electrical and Electronics Engineers (IEEE). - 0018-9294 .- 1558-2531. ; 69:1, s. 513-524
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Journal article (peer-reviewed)abstract
- Objective: Hydrodynamic cavitation is characterized by the formation of bubbles inside a flow due to local reduction of pressure below the saturation vapor pressure. The resulting growth and violent collapse of bubbles lead to a huge amount of released energy. This energy can be implemented in different fields such as heat transfer enhancement, wastewater treatment and chemical reactions. In this study, a cystoscope based on small scale hydrodynamic cavitation was designed and fabricated to exploit the destructive energy of cavitation bubbles for treatment of tumor tissues. The developed device is equipped with a control system, which regulates the movement of the cystoscope in different directions. According to our experiments, the fabricated cystoscope was able to locate the target and expose cavitating flow to the target continuously and accurately. The designed cavitation probe embedded into the cystoscope caused a significant damage to prostate cancer and bladder cancer tissues within less than 15 minutes. The results of our experiments showed that the cavitation probe could be easily coupled with endoscopic devices because of its small diameter. We successfully integrated a biomedical camera, a suction tube, tendon cables, and the cavitation probe into a 6.7 mm diameter cystoscope, which could be controlled smoothly and accurately via a control system. The developed device is considered as a mechanical ablation therapy, can be a solid alternative for minimally invasive tissue ablation methods such as radiofrequency (RF) and laser ablation, and could have lower side effects compared to ultrasound therapy and cryoablation.
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| 6. |
- Abbasiasl, Taher, et al.
(author)
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Effect of intensified cavitation using poly (vinyl alcohol) microbubbles on spray atomization characteristics in microscale
- 2020
-
In: AIP Advances. - : American Institute of Physics (AIP). - 2158-3226. ; 10:2
-
Journal article (peer-reviewed)abstract
- In this study, cavitating flows inside a transparent cylindrical nozzle with an inner diameter of 0.9 mm were visualized, and the effect of cavitation on atomization characteristics of emerging sprays was investigated. Different patterns of cavitating flows inside the nozzle were visualized using a high-speed camera. In-house codes were developed to process the captured images to study the droplet size distribution and droplet velocity in different flow regimes. The results show that cavitating flows at the microscale have significant effects on atomization characteristics of the spray. Two working fluids, namely, water and poly(vinyl alcohol) microbubble (PVA MB) suspension, were employed. Accordingly, the injection pressures were detected as 690 kPa, 1035 kPa, and 1725 kPa for cavitation inception, supercavitation, and hydraulic flip flow regimes in the case of water, respectively. The corresponding pressures for the aforementioned patterns for PVA MB suspension were 590 kPa, 760 kPa, and 1070 kPa, respectively. At the microscale, as a result of a higher volume fraction of cavitation bubbles inside the nozzle, there is no large difference between the cavitation numbers corresponding to cavitating and hydraulic flip flows. Although the percentage of droplets with diameters smaller than 200 μm was roughly the same for both cases of water and PVA MB suspension, the Sauter mean diameter was considerably lower in the case of PVA MBs. Moreover, higher droplet velocities were achieved in the case of PVA MBs at lower injection pressures.
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| 7. |
- Aghdam, Araz Sheibani, et al.
(author)
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A New Method for Intense Cavitation Bubble Generation on Layer-by-Layer Assembled SLIPS
- 2019
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In: Scientific Reports. - : Nature Publishing Group. - 2045-2322. ; 9
-
Journal article (peer-reviewed)abstract
- The importance of surface topology for the generation of cavitating flows in micro scale has been emphasized during the last decade. In this regard, the utilization of surface roughness elements is not only beneficial in promoting mass transportation mechanisms, but also in improving the surface characteristics by offering new interacting surface areas. Therefore, it is possible to increase the performance of microfluidic systems involving multiphase flows via modifying the surface. In this study, we aim to enhance generation and intensification of cavitating flows inside microfluidic devices by developing artificial roughness elements and trapping hydrophobic fluorinated lubricants. For this, we employed different microfluidic devices with various hydraulic diameters, while roughness structures with different lengths were formed on the side walls of microchannel configurations. The surface roughness of these devices was developed by assembling various sizes of silica nanoparticles using the layer-by-layer technique (D2). In addition, to compare the cavitating flow intensity with regular devices having plain surfaces (D1), highly fluorinated oil was trapped within the pores of the existing thin films in the configuration D2 via providing the Slippery Liquid-Infused Porous Surface (D3). The microfluidic devices housing the short microchannel and the extended channel were exposed to upstream pressures varying from 1 to 7.23 MPa. Cavitation inception and supercavitation condition occured at much lower upstream pressures for the configurations of D2 and D3. Interestingly, hydraulic flip, which rarely appears in the conventional conical nozzles at high pressures, was observed at moderate upstream pressures for the configuration D2 proving the air passage existence along one side of the channel wall.
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| 8. |
- Ali, Kosar M., et al.
(author)
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Biomarkers of type 2 and non-type 2 inflammation in asthma exacerbations
- 2024
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In: Central European Journal of Immunology. - : Termedia. - 1426-3912 .- 1644-4124. ; 49:2, s. 1-11
-
Journal article (peer-reviewed)abstract
- Introduction: in adult-onset asthma, two major endotypes have been proposed: t2 with eosinophilia and non-t2 characterised by neutrophils and interleukin (il)-17. the objective of the study was to exam-ine the endotype marker profile in patients with severe asthma who were hospitalized for exacerbations, with a focus on differentiating between viral and non-viral triggers.Material and methods: Forty-nine patients with asthma, admitted for exacerbations, and 51 healthy controls (hCs) were recruited. We further categorized the exacerbated asthma patients into two groups: non-viral infected (n = 38) and viral infected (n = 11) groups. Blood was drawn and a nasopharyngeal swab taken at the time of admission and eosinophil numbers, eosinophil cationic protein (eCP), immuno- globulin e (ige), tryptase and viral infection were determined. additionally, levels of il-17, il-33 and il-31 were assessed.Results: the majority of patients had adult onset asthma (age of diagnosis, 42.8 ±16.1) with a du-ration of 7.7 ±10.8 years, 24.5% being atopic. Patients had higher levels of eosinophils, eCP and ige than healthy controls (eosinophils, p = 0.003; eCP and ige, p = 0.0001). immunohistochem-istry confirmed eosinophils as a source of eCP. tryptase (p = 0.0001), il-17 (p = 0.0005), il-31 (p = 0.0001) and il-33 (p = 0.0002) were also higher in patients than controls. eCP correlated with tryptase (r = 0.08, p = 0.62). il-17 showed the best correlation with other mediators, including eCP (r = 0.35, p = 0.24), tryptase (r = 0.69, p = 0.0001), ige (r = 0.50, p = 0.0001), il-33 (r = 0.95, p = 0.0001) and il-31 (r = 0.89, p = 0.0001). ige, il-17, and il-31 had a high auC when differentiating those with severe and non-severe asthma. the group with exacerbated viral infection showed elevated levels of serum il-17 and il-31 compared to the non-infected group.Conclusions: Patients with asthmatic exacerbations were found to have higher levels of both t2 and non-t2 inflammatory markers than healthy controls. in the study, levels of ige, il-17, and il-31 differentiated between patients with severe and non-severe asthma. the last two cytokines were also able to distinguish between exacerbated asthma caused by viral infection and exacerbated asthma caused by non-viral infection.
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| 9. |
- Amin, Kawa, et al.
(author)
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Evidence for eosinophil and IL-17 mediated inflammation in allergic rhinitis
- 2020
-
In: Clinical and Molecular Allergy. - : Springer Science and Business Media LLC. - 1476-7961. ; 18
-
Journal article (peer-reviewed)abstract
- Background: The aim was to determine the level of inflammatory cytokines, eosinophil cationic protein and IgE in allergic rhinitis (AR) patients.Subjects and methods: Blood samples were taken from 88 AR patients and 88 healthy controls (HC). Each sample was analysed for eosinophil counts by flow cytometry, IgE by ECLIA, ECP, IL-17, and IL-33 by using ELISA test.Results: There was no significant difference between AR patients and the control group in age and gender. Levels of eosinophils, IgE, ECP, IL-17, IL-33 and the total symptom scores were significantly higher in AR patients than the HC (P = 0.0001). Serum ECP correlated with IL-17 (P = 0.041, r = 0.42), IL-33 (P = 0.0001, r = 080), and IgE levels (P = 0.017, r = 0.45) in the R patients. There was no correlation between IL-17 and IL-33. There was a correlation between symptom scores and eosinophils (P = 0.026, r = 0.52), and IgE (P = 0.001, r = 0.60) in the patients. No correlation was observed between symptom scores and ECP, IL-17, and IL-33 in the AR patient.Conclusions: Patients with AR have significant higher serum levels of ECP, IL-17, and IL-33 than healthy controls. This indicates that these markers could be used to in order to diagnose AR and to monitor disease. Inhibitory molecules to IL-17 and IL-33 may be considered as novel treatment strategies.
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| 10. |
- Amin, Kawa, et al.
(author)
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Hepatic Immune Response to Environmental Carcinogens
- 2018
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In: Pharmacognosy Magazine. - : EManuscript Technologies. - 0973-1296 .- 0976-4062. ; 14:58, s. 548-553
-
Journal article (peer-reviewed)abstract
- Aim: Environmental carcinogenic substances contribute to increasing incidence of hepatocellular carcinoma (HCC). We employed a sensitive method for the detection of DNA damage combined with analysis of the immune response to gain better knowledge how environmental carcinogens mediate pathology.Materials and Methods: Rat hepatocytes were isolated and stimulated with carcinogenic substances for the assessment of DNA damage. The mycotoxin aflatoxin B-1 (AFB(1)), two heterocyclic amines from the cooking of meat amino-3-methylimidazo[4,5-f] quinoline (IQ) and 3-amino-1-methyl-5H-pyr ido-(4,3-b)-indole (TRP-P-2), and protein extract from the fungus Lactarius necator were assayed. Unscheduled DNA synthesis in hepatocytes was measured by the incorporation of radioactive thymidine during DNA repair. Stimulation of hepatocyte/immune cell preparation with the substances and measurement of IFN gamma release at different time points determined their ability to induce an inflammatory response.Results: DNA repair in the hepatocytes was induced in response to 10(-7) M AFB(1) and 10(-9) M IQ. TRP-P-2 did not induce DNA repair; however, at 10(-4) M, the fungus extract did this. Furthermore, liver-resident immune cells responded with differential production of IFN gamma over time in response to stimulation by all the carcinogens, with AFB(1) being the most potent. TRP-P-2 showed the most significant reduction in IFN gamma response over time.Conclusion: DNA damage in hepatocytes induced by environmental substances was detected at low molecular concentrations. The system did provide novel evidence for hepatic carcinogenicity by the fungus L. necator. Analysis of the response by liver-resident immune cells to the substances suggested that highly mutagenic substances induce prolonged inflammatory response.
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| 11. |
- Gevari, Moein Talebian, et al.
(author)
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Deagglomeration of nanoparticle clusters in a "cavitation on chip" device
- 2020
-
In: AIP Advances. - : AIP Publishing. - 2158-3226. ; 10:11
-
Journal article (peer-reviewed)abstract
- Due to the potential of significant energy release in cavitating flows, early cavitation inception and intensification of cavitating flows are of great importance. To use this potential, we investigated the deagglomeration of nanoparticle clusters with the implementation of hydrodynamic cavitation in a microfluidic device. For this purpose, a microfluidic device with a micro-orifice geometry was designed and fabricated using standard microfabrication processes. The system was tested with distilled water in the assembled experimental setup. The flow patterns were characterized using the cavitation number and inlet pressure. Titania nanoparticles were utilized to prepare nanoparticle suspensions. The suspensions were heated to allow agglomeration of nanoparticles. The system was operated with the new working fluid (nanoparticle clusters) at different inlet pressures. After characterizing flow patterns, the flow patterns were compared with those of pure water. The deagglomeration effects of hydrodynamic cavitation on nanoparticle clusters showed the possibility to apply this method for the stabilization of nanoparticles, which paves way to the implementation of nanoparticle suspensions to thermal fluid systems for increased energy efficiency as well as to drug delivery. Our results also indicate that the presence of nanoparticles in the working fluid enhanced cavitation intensity due to the increase in the number of heterogeneous nucleation sites.
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| 12. |
- Gevari, Moein Talebian, et al.
(author)
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Direct and indirect thermal applications of hydrodynamic and acoustic cavitation : A review
- 2020
-
In: Applied Thermal Engineering. - : Elsevier. - 1359-4311 .- 1873-5606. ; 171
-
Research review (peer-reviewed)abstract
- The phase change phenomenon in fluids as a result of low local pressure under a critical value is known as cavitation. Acoustic wave propagation or hydrodynamic pressure drop of the working fluid are the main reasons for inception of this phenomenon. Considering the released energy from the collapsing cavitation bubbles as a reliable source has led to its implementation to different fields, namely, heat transfer, surface cleaning and fouling, water treatment, food industry, chemical reactions, energy harvesting. A considerable amount of energy in the mentioned industries is required for thermal applications. Cavitation could serve for minimizing the energy demand and optimizing the processes. Thus, the energy efficiency of the systems could be significantly enhanced. This review article focuses on the direct and indirect thermal applications of hydrodynamic and acoustic cavitation. Relevant studies with emerging applications are discussed, while developments in cavitation, which have given rise to thermal applications during the last decade, are also included in this review.
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| 13. |
- Gevari, Moein Talebian, et al.
(author)
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Influence of Fluid Properties on Intensity of Hydrodynamic Cavitation and Deactivation of Salmonella typhimurium
- 2020
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In: Processes. - : MDPI. - 2227-9717. ; 8:3
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Journal article (peer-reviewed)abstract
- In this study, three microfluidic devices with different geometries are fabricated on silicon and are bonded to glass to withstand high-pressure fluid flows in order to observe bacteria deactivation effects of micro cavitating flows. The general geometry of the devices was a micro orifice with macroscopic wall roughness elements. The width of the microchannel and geometry of the roughness elements were varied in the devices. First, the thermophysical property effect (with deionized water and phosphate-buffered saline (PBS)) on flow behavior was revealed. The results showed a better performance of the device in terms of cavitation generation and intensity with PBS due to its higher density, higher saturation vapor pressure, and lower surface tension in comparison with water. Moreover, the second and third microfluidic devices were tested with water and Salmonella typhimurium bacteria suspension in PBS. Accordingly, the presence of the bacteria intensified cavitating flows. As a result, both devices performed better in terms of the intensity of cavitating flow with the presence of bacteria. Finally, the deactivation performance was assessed. A decrease in the bacteria colonies on the agar plate was detected upon the tenth cycle of cavitating flows, while a complete deactivation was achieved after the fifteenth cycle. Thus, the proposed devices can be considered as reliable hydrodynamic cavitation reactors for "water treatment on chip" applications.
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| 14. |
- Ghorbani, Morteza, et al.
(author)
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Facile Hydrodynamic Cavitation ON CHIP via Cellulose Nanofibers Stabilized Perfluorodroplets inside Layer-by-Layer Assembled SLIPS Surfaces
- 2019
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In: Chemical Engineering Journal. - : Elsevier. - 1385-8947 .- 1873-3212.
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Journal article (peer-reviewed)abstract
- The tremendous potential of “hydrodynamic cavitation on microchips” has been highlighted during recent years in various applications. Cavitating flow patterns, substantially depending upon thermophysical and geometrical characteristics, promote diverse industrial and engineering applications, including food and biomedical treatment. Highly vaporous and fully developed patterns in microfluidic devices are of particular interest. In this study, the potential of a new approach, which includes cellulose nanofiber (CNF)- stabilized perfluorodroplets (PFC5s), was assessed inside microfluidic devices. The surfaces of these devices were modified by assembling various sizes of silica nanoparticles, which facilitated in the generation of cavitation bubbles. To examine the pressure effects on the stabilized droplets in the microfluidic devices, the upstream pressure was varied, and the cavitation phenomenon was characterized under different experimental conditions. The results illustrate generation of interesting, fully developed, cavitating flows at low pressures for the stabilized droplets, which has not been previously observed in the literature. Supercavitation flow pattern, filling the entire microchannel, were recorded at the upstream pressure of 1.7 MPa for the case of CNF-stabilized PFC5s, which hardly corresponds to cavitation inception for pure water in the same microfluidic device.
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| 15. |
- Jafarpour, Mohammad, et al.
(author)
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An ecologically friendly process for graphene exfoliation based on the "hydrodynamic cavitation on a chip" concept
- 2021
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In: RSC Advances. - : Royal Society of Chemistry (RSC). - 2046-2069. ; 11:29, s. 17965-17975
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Journal article (peer-reviewed)abstract
- Tremendous research efforts have recently focused on the synthesis of graphene from graphitic materials, while environmental issues, scalability, and cost are some of the major challenges to be surmounted. Liquid phase exfoliation (LPE) of graphene is one of the principal methods for this synthesis. Nevertheless, sufficient information about the mechanisms of exfoliation has yet to emerge. Here, a microreactor based on the hydrodynamic cavitation (HC) on a chip concept is introduced to exfoliate graphite in a totally green process which involves only natural graphite flakes and water. HC-treated graphitic materials were characterized by UV-Vis and Raman spectroscopy, DLS (Dynamic Light Scattering), AFM (Atomic Force Microscopy), and SEM (Scanning Electron Microscopy) analyses. The present sustainable reactor system was found to exfoliate thick and large graphite particles to nano-sized sheets (similar to 1.2 nm) with a lateral size of similar to 500 nm to 5 mu m.
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| 16. |
- Jafarpour, Mohammad, et al.
(author)
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Electrospinning of ternary composite of PMMA-PEG-SiO2 nanoparticles : Comprehensive process optimization and electrospun properties
- 2021
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In: Materials Today Communications. - : Elsevier BV. - 2352-4928. ; 29
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Journal article (peer-reviewed)abstract
- Electrospinning has been realized to be a promising method for creating nano-composite fibers due to its significant growth for producing innovative composites with advanced applications. In this method a polymeric solution subjected to an electrohydrodynamic process and slim charged liquid jet is formed inside a high potential electric field. The high voltage enables the production of continuously long fibers on a collector surface. Addition of different polymers and NPs to the one-component solution to modify the physicochemical characteristic and decorating the surface of electrospun fibers has proven to be challenging and imperative for many fields especially novel bioengineering and filtration applications. In this study, the effects of major parameters on the fabrication of electrospun fibers were extensively investigated. At the first step, formation of nanofibers on the surface of collector and optimization of process parameters were determined based on the mean diameter of resulting fibers, through SEM (Scanning Electron Microscopy) images. The optimum values for concentration, applied voltage, the distance between the tip of needle and collector, and flow rate determined to be 10 wt%, 12 kV, 20 cm, and 0.6 mL h(-1), respectively. Afterwards, the hydrophilicity of fibers was modified by adding different poly (ethylene glycol) (PEG) concentrations (20, 30, and 40 wt%) to the polymeric solution. The contact angle analysis revealed that the poly (methyl methacrylate) (PMMA) and 30 wt% PEG fabricated fibrous mat exhibited a better wettability and 71.61% lower hydrophobicity compared to pure PMMA electrospun mats. In the next step, silica NPs (nanoparticles) were introduced to the polymeric solution of electrospinning in the form of an IPA (isopropanol)-based collide solution. The dispersed solution-based addition of silica NPs prevented the aggregation state of NPs in the nanofibers. The addition of silica nanoparticles also changed the thermal and mechanical properties of the ternary composite, which were analyzed in TGA (thermogravimetric analysis) and tensile tests. Noteworthy, the addition of 30% PEG and silica NPs increase 3 times the tensile strength and around 2 times elongation in comparison with pure PMMA electrospun mats. These results highlight that the hybrid composite leads to a promising new electrospun mat for filtration and bioengineering applications.
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| 17. |
- Rokhsar Talabazar, Farzad, et al.
(author)
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Design and fabrication of a vigorous "cavitation-on-a-chip" device with a multiple microchannel configuration
- 2021
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In: Microsystems & Nanoengineering. - : Springer Nature. - 2055-7434. ; 7:1
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Journal article (peer-reviewed)abstract
- Hydrodynamic cavitation is one of the major phase change phenomena and occurs with a sudden decrease in the local static pressure within a fluid. With the emergence of microelectromechanical systems (MEMS), high-speed microfluidic devices have attracted considerable attention and been implemented in many fields, including cavitation applications. In this study, a new generation of 'cavitation-on-a-chip' devices with eight parallel structured microchannels is proposed. This new device is designed with the motivation of decreasing the upstream pressure (input energy) required for facile hydrodynamic cavitation inception. Water and a poly(vinyl alcohol) (PVA) microbubble (MB) suspension are used as the working fluids. The results show that the cavitation inception upstream pressure can be reduced with the proposed device in comparison with previous studies with a single flow restrictive element. Furthermore, using PVA MBs further results in a reduction in the upstream pressure required for cavitation inception. In this new device, different cavitating flow patterns with various intensities can be observed at a constant cavitation number and fixed upstream pressure within the same device. Moreover, cavitating flows intensify faster in the proposed device for both water and the water-PVA MB suspension in comparison to previous studies. Due to these features, this next-generation 'cavitation-on-a-chip' device has a high potential for implementation in applications involving microfluidic/organ-on-a-chip devices, such as integrated drug release and tissue engineering.
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| 18. |
- Talabazar, Farzad Rokhsar, et al.
(author)
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Cavitation inception and evolution in cavitation on a chip devices at low upstream pressures
- 2023
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In: Physics of fluids. - : AIP Publishing. - 1070-6631 .- 1089-7666. ; 35:1
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Journal article (peer-reviewed)abstract
- The concept of "hydrodynamic cavitation on a chip" offers facile generation of cavitating flows in microdomains, which can be easily scaled up by arranging short microchannels (micro-orifices) in cascade formations. In this regard, microscale cavitation in an energy-efficient test rig has the potential of increasing utilization possibilities of cavitation in a wide range of applications such as liquid-phase exfoliation. In this study, a new experimental test rig was constructed to generate microscale hydrodynamic cavitation. This setup enables cavitation bubble generation at low upstream pressures through the control of the downstream pressure of the device. Particular attention was directed to the classification of flow patterns, scale effects, and cavitating flow evolutions with an in-depth categorization of underlying mechanisms such as Kelvin-Helmholtz instability. Cavitation inception appeared in the form of a single bubble. The appearance of different attached cavitating flow patterns within the microfluidic device was accompanied by new physics, which revealed that cavitation generation and development are affected by the existence of various fluid flow phenomena, particularly the jet flow. The outcome of this study makes hydrodynamic cavitation on a chip attractive for applications, where the cavitation effects are sought in the presence of multiphase fluid flows.
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| 19. |
- Talabazar, Farzad Rokhsar, et al.
(author)
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Chemical effects in "hydrodynamic cavitation on a chip" : The role of cavitating flow patterns
- 2022
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In: Chemical Engineering Journal. - : Elsevier BV. - 1385-8947 .- 1873-3212. ; 445
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Journal article (peer-reviewed)abstract
- Amongst the advanced oxidation processes (AOPs), hydrodynamic cavitation (HC) has emerged as one of the most cost-efficient, simple and ecologically friendly approaches in the recent decade. This type of the cavitation, in contrast to its counterpart (acoustic cavitation), has a huge potential to upscale to the industrial levels. In the recent years, the micro-scale HC (HC on a chip concept) has exhibited favorable efficacy in terms of nucleation type, surface effects and flow pattern dominancy. In this study, the chemical effects of the HC on a chip concept are shown for the first time by considering the effects of the cavitating flow patterns. So, this is the first attempt to understand the effects of the inception and developed cavitating flow patterns on the chemical reactions during the bubble collapse in the micro-scale. In addition, a particular attention is paid to the chemical reaction effects before the cavitation bubble observation in this investigation. Our results indicated that the triiodide releasing amount was interestingly maximum before the inception occurred, especially at the first cycle. The released amount decreased at the inception and increased for the case of the developed twin cavities. We also showed that, comparing to our previous studies, the cavitation arrived at a relatively lower upstream pressure in the open loop cavitation test rig. Therefore, the outcome of this approach reveals the significance of the in-depth investigations of the complex and very transient nature of the cavitation at different flow patterns. Furthermore, this study implied that reactors benefitting HC on a chip concept will be environmentally friendly tools for producing products from the wastes and worthless materials in the near future.
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| 20. |
- Talabazar, Farzad Rokhsar, et al.
(author)
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Removal of per- and polyfluoroalkyl substances (PFAS) from wastewater using the hydrodynamic cavitation on a chip concept
- 2024
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In: Chemical Engineering Journal. - : Elsevier BV. - 1385-8947 .- 1873-3212. ; 495
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Journal article (peer-reviewed)abstract
- The elimination of micropollutants such as highly fluorinated substances, including per- and polyfluoroalkyl substances (PFAS), in wastewater treatment plants has been receiving growing attention due to the urgent need to minimize their adverse effects on natural water and associated ecosystems. Conventional treatment methods often fall short in effectively removing PFAS. In this study, the Hydrodynamic Cavitation on a Chip concept (HCOC) was utilized to degrade 11 common PFAS variants (PFAS11) for the first time in three different hydrodynamic cavitation reactor set-ups, each enhanced with surface modifications involving roughness elements. Stockholm municipal wastewater treated by a Membrane BioReactor (MBR) process was subjected to fully developed cavitating flow treatment using the three distinct microscale hydrodynamic cavitation (HC) reactors. The obtained results indicate that the chemical-free HCOC technique employed in this study has a significant potential in the degradation of nearly all investigated PFAS11 compounds at a notable rate of 36.1 % while the combination with MBR process can prevent blockage within the fluidic channels, enabling continuous operation with high throughput processing rates. Our proposed methodology demonstrated promising results in eliminating PFAS and could contribute to advancements in the use of microscale HC to treat micropollutants in wastewater. These findings could be a major leap in water treatment technologies addressing the global burden of resource-efficient micropollutant water treatment.
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| 21. |
- Talebian Gevari, Moein, et al.
(author)
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Energy harvesting with micro scale hydrodynamic cavitation-thermoelectric generation coupling
- 2019
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In: AIP Advances. - : American Institute of Physics (AIP). - 2158-3226. ; 9
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Journal article (peer-reviewed)abstract
- In this study, energy harvesting with micro scale hydrodynamic cavitation-thermoelectric generation coupling is investigated. For this, three micro orifices with different geometrical dimensions are fabricated. The hydraulic diameter of the micro orifices are 66.6 mu m, 75.2 mu m, and 80 mu m, while their length is the same (2000 mu m). Two different working fluids, namely water and Perfluoropentane droplet-water suspension, are utilized for cavitating flows in the fabricated micro orifices. The flow patterns at different upstream pressures are recorded using the high-speed camera system, and the experimental results are analyzed and compared. Thereafter, energy harvesting perspectives of cavitating flows are considered. The released heat from collapsing bubbles and the subsequent temperature rise on the end wall of the microchannel, which can be used as the source for the power generation, is calculated over time. Finally, a miniature energy harvesting system with cavitation system and thermoelectric generator coupling is presented. The maximum power corresponding to two different thermoelectric generators is estimated for with both working fluids and is compared with the required power to run miniature daily used electronics components.
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| 22. |
- Talebian Gevari, Moein, et al.
(author)
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Local Carpet Bombardment of Immobilized Cancer Cells With Hydrodynamic Cavitation
- 2021
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In: IEEE Access. - : Institute of Electrical and Electronics Engineers (IEEE). - 2169-3536. ; 9, s. 14983-14991
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Journal article (peer-reviewed)abstract
- This study presents a method based on carpet bombardment of immobilized cells with cavitating flows. For this, immobilized cancer cell lines are exposed to micro scale cavitating flows from the tip of a micro nozzle under the effect of cavitation microbubbles. The deformation as a result of cavitation bubbles on exposed cells differs from one cell type to another. Therefore, the difference in cell deformation upon cavitation exposure (carpet bombardment) acts as a valuable indicator for cancer diagnosis. The developed system is tested on HCT-116 (Human Colorectal Carcinoma), MDA-MB-231 (Breast Adenocarcinoma), ONCO-DG-1 (Ovarian Adenocarcinoma) cell lines due to their clinical importance. The mechanical effects of cavitation are examined by considering the single-cell lysis effect (the cell membrane is ruptured, and the cell is destroyed) with the help of the Scanning Electron Microscopy (SEM) technique. Our study proposes a promising label-free method for the potential use in cancer diagnosis with cavitation bubble collapse, where microbubbles could be precisely controlled and directed to the desired locations, as well as the characterization of the biophysical properties of cancer cells. The proposed approach tool has the advantages of label-free approach, simple structure and low cost and is a substantial alternative for the existing tools.
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