The effect of in-situ cellulosic matrix on the photophysical properties of white emissive CQDs

Montazeri Fereshteh,Ghasedi Arman,Mahdavi Behnam,Koushki Ehsan 한국탄소학회 2024 Carbon Letters Vol.34 No.1

Carbon quantum dots (CQDs), the newest member of carbonaceous nanomaterials, have drawn many considerations since the past two decades. A vast number of researchers made their efforts to demystify optical behavior of these materials despite being demanding. Nevertheless, their emission origin is still a controversial issue and this area suffers from a lack of hypothesis to explain the radiative transitions of these materials. White emissive CQDs are more prized among the other ones since it has provided an affordable warm white light source for many applications. In this paper, white emissive CQDs samples were prepared through a one-step hydrothermal synthesis approach. By using the advantage of possessing cellulosic networks in the Aloe Vera gel an in-situ matrix was created to encase CQDs particles. During the formation of CQDs particles, they were entrapped and created RGB nanoemitters in the cellulosic units. The leakage of the emitted photons during the radiative transitions followed by inner-filter effect (IFE) and self-/re-absorption acted as white light emissive sources. To scrutinize the validity and possibility of the hypothesis given in this paper, a series of spectroscopic analyses, including transmission electron microscopy (TEM), surface-enhanced Raman scattering (SERS), Fourier Transform Infrared (FT-IR), ultraviolet–visible (UV–Vis), and photoluminescence (PL) were conducted.

Overexpression of Cyclin E and its Low Molecular Weight Isoforms Cooperate with Loss of p53 in Promoting Oncogenic Properties of MCF-7 Breast Cancer Cells

Montazeri, Hamed,Bouzari, Saeid,Azadmanesh, Kayhan,Ostad, Seyed Nasser,Ghahremani, Mohammad Hossein Asian Pacific Journal of Cancer Prevention 2015 Asian Pacific journal of cancer prevention Vol.16 No.17

Cyclin E, a key coordinator of the G1 to S transition in the cell cycle, may be deregulated in several malignancies, including breast cancer. The most significant aberration in cyclin E is its elastase mediated proteolytic cleavage into tumor specific low molecular weight isoforms (LMW-Es). LMW-Es are biochemically hyperactive and biologically drive tumorigenesis in transgenic mouse models. Additionally, expression of LMW-Es has been correlated with poor survival in breast cancer cases. Here we determine whether expression of LMW-Es in a breast cancer cell line that is naturally devoid of these deregulated forms would alter their progression through each phase of the cell cycle. The results revealed that LMW-Es expression resulted in an increased doubling time, concomitant with a predominant increase in the population in the S phase of the cell cycle. Moreover, downregulation of p53 in LMW-Es cells resulted in additional shortening of the doubling time and enrichment of cells in the S and G2/M phases of the cell cycle. Furthermore, expression of LMW-Es sensitized cells to ${\beta}$-estradiol (E2) mediated growth and changed expression patterns of estrogen receptor and Bcl-2. Intriguingly, expression of LMW-Es could surpass anti-apoptotic effects raised by p53 upregulation. Taken together these studies suggest that overexpression of LMW-Es in collaboration with p53 loss results in altered g rowth properties of MCF-7 cells, enhancing the oncogenic activity of these ER positive breast cancer cells.

Investigation of the semi-active electromagnetic damper

Montazeri-Gh, Morteza,Kavianipour, Omid Techno-Press 2014 Smart Structures and Systems, An International Jou Vol.13 No.3

In this paper, the electromagnetic damper (EMD), which is composed of a permanent-magnet rotary DC motor, a ball screw and a nut, is considered to be analyzed as a semi-active damper. The main objective pursued in the paper is to study the two degrees of freedom (DOF) model of the semi-active electromagnetic suspension system (SAEMSS) performance and energy regeneration controlled by on-off and continuous damping control strategies. The nonlinear equations of the SAEMSS must therefore be extracted. The effects of the EMD characteristics on ride comfort, handling performance and road holding for the passive electromagnetic suspension system (PEMSS) are first analyzed and damping control strategies effects on the SAEMSS performance and energy regeneration are investigated next. The results obtained from the simulation show that the SAEMSS provides better performance and more energy regeneration than the PEMSS. Moreover, the results reveal that the on-off hybrid control strategy leads to better performance in comparison with the continuous skyhook control strategy, however, the energy regeneration of the continuous skyhook control strategy is more than that of the on-off hybrid control strategy (except for on-off skyhook control strategy).

Microscopic analysis of thin-film evaporation on spherical pore surfaces

Montazeri, Kimia,Lee, Hyoungsoon,Won, Yoonjin Pergamon Press 2018 International journal of heat and mass transfer Vol. No.

<P><B>Abstract</B></P> <P>As electronic systems become miniaturized, it is crucial to implement optimal cooling technologies to dissipate high heat levels. Evaporation cooling for electronics systems has been considered one of the most promising approaches for meeting the demands of high-powered technologies by taking advantage of their latent heat. Integrating microscale or nanoscale features into two-phase microfluidic cooling systems such as porous media can dramatically increase the area of liquid-vapor interfaces where phonons translate thermal energy to fluid enthalpy. To achieve this performance jump, it is essential to understand how the engineered features improve evaporative heat transfer performance. In this study, we investigate thin-film evaporation performance within crystalline pore surfaces by employing simulation models that examine solid-liquid contact lines and liquid-vapor interfaces. The simulation models compute detailed performance parameters including phase volume fraction, temperature, pressure profile, and evaporative mass flux as a function of location, allowing us to calculate local heat transfer performance parameters. Based on local heat transfer performances, we identify thin-film regions and quantify their fractions to the overall evaporation performance. Area-averaged heat transfer coefficients are compared to identify the morphological effects of varying pore diameters and surface wettability. Insights from this parametric study will allow us to understand how evaporative heat transfer is related to the structural details of porous media and assist us to determine guidelines for the design of evaporating surfaces in modern electronics cooling.</P> <P><B>Highlights</B></P> <P> <UL> <LI> We employ the volume of fluid method based on the modified Schrage theory. </LI> <LI> We study local evaporation performances on pore surface as a function of radial locations. </LI> <LI> We identify three evaporation regions and their impacts on overall performance. </LI> <LI> We calculate the area-averaged heat transfer performances for various cases. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

Investigation of the semi-active electromagnetic damper

Morteza Montazeri-Gh,Omid Kavianipour 국제구조공학회 2014 Smart Structures and Systems, An International Jou Vol.13 No.3

In this paper, the electromagnetic damper (EMD), which is composed of a permanent-magnet rotary DC motor, a ball screw and a nut, is considered to be analyzed as a semi-active damper. The main objective pursued in the paper is to study the two degrees of freedom (DOF) model of the semi-active electromagnetic suspension system (SAEMSS) performance and energy regeneration controlled by on-off and continuous damping control strategies. The nonlinear equations of the SAEMSS must therefore be extracted. The effects of the EMD characteristics on ride comfort, handling performance and road holdingfor the passive electromagnetic suspension system (PEMSS) are first analyzed and damping control strategies effects on the SAEMSS performance and energy regeneration are investigated next. The results obtained from the simulation show that the SAEMSS provides better performance and more energy regeneration than the PEMSS. Moreover, the results reveal that the on-off hybrid control strategy leads to better performance in comparison with the continuous skyhook control strategy, however, the energy regeneration of the continuous skyhook control strategy is more than that of the on-off hybrid controlstrategy (except for on-off skyhook control strategy).

Comparison of model predictive controller and optimized min-max algorithm for turbofan engine fuel control

Morteza Montazeri-Gh,Ali Rasti 대한기계학회 2019 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.33 No.11

Min-max selector structure is traditionally used as the industrial control architecture of commercial turbofan engines. However, recent studies indicate that this structure with linear compensators suffers from lack of safety guarantee in fast demands. On the other hand, model predictive control (MPC) technique, which incorporates input/output constraints in its optimization process, has the potential to fulfill the control requirements of an aircraft engine. In this paper, a practical approach is performed for design and optimization of the turbofan engine controller through a comparative study where all control modes and requirements have been taken into account simultaneously. For this purpose, a thermodynamic nonlinear model is firstly developed for the turbofan engine. The linear regulators of minmax structure are then optimized via genetic algorithm (GA). The MPC technique is formulated based on the proper discrete-time linearized state-space models at desired operating points with real-time optimization, in which the MPC tuning horizons are obtained through GA optimization procedure. The both controllers are implemented on appropriate hardware taking the real-time aspects into account. Finally, a hardware in the loop (HIL) platform is developed for the turbofan engine electronic control unit (ECU) testing. The software and HIL simulation results confirm that MPC improves the response time of the system in comparison with min-max algorithm and guarantees the engine limit protection. This study demonstrates competitive advantages of MPC in terms of limit protection assurance and fast response, despite more computational burden.

Soft Fault Detection Using an Improved Mechanism in Wireless Sensor Networks

( Mojtaba Montazeri ),( Rasoul Kiani ) 한국인터넷정보학회 2018 KSII Transactions on Internet and Information Syst Vol.12 No.10

Wireless sensor networks are composed of a large number of inexpensive and tiny sensors used in different areas including military, industry, agriculture, space, and environment. Fault tolerance, which is considered a challenging task in these networks, is defined as the ability of the system to offer an appropriate level of functionality in the event of failures. The present study proposed an intelligent throughput descent and distributed energy-efficient mechanism in order to improve fault tolerance of the system against soft and permanent faults. This mechanism includes determining the intelligent neighborhood radius threshold, the intelligent neighborhood nodes number threshold, customizing the base paper algorithm for distributed systems, redefining the base paper scenarios for failure detection procedure to predict network behavior when running into soft and permanent faults, and some cases have been described for handling failure exception procedures. The experimental results from simulation indicate that the proposed mechanism was able to improve network throughput, fault detection accuracy, reliability, and network lifetime with respect to the base paper.

Molecular Dynamics Modeling of Buckling Behavior of Hydrogenated Graphyne

A. Montazeri,S. Ebrahimi,A. Rajabpour,H. Rafii-Tabar 성균관대학교(자연과학캠퍼스) 성균나노과학기술원 2015 NANO Vol.10 No.7

Molecular dynamics simulation is employed to explore the influence of hydrogen adsorption on the stability behavior of graphyne (GY) as a new allotrope of carbon. The strain for the onset of buckling is determined for pristine GY and the results are compared with those for perfect graphene nanoribbons under identical conditions. The results reveal that due to the presence of triple C–C bonds in the GY structure, which are harder to rotate and bend in compression compared to single bonds, the new allotrope is stiffer than graphene during buckling phenomenon. In addition, the effect of hydrogen adsorption on the stability behavior of GY is examined with different H coverage in the range 0–50%. It is concluded that this adsorption promotes a rapid buckling which is attributed to the conversion of the stiff in-plane carbon bonding in the GY structure to the out-of-plane bonding which is weaker and easier to bend in compression. Finally, a critical value of adsorption is found above in which such a trend is not observed.

Energy saving in carbon dioxide hydrate formation process using Boehmite nanoparticles

Vahab Montazeri,Masoud Rahimi,Bahman ZareNezhad 한국화학공학회 2019 Korean Journal of Chemical Engineering Vol.36 No.11

This work reports on an attempt to save energy in the carbon dioxide hydrate formation process. The kinetics of carbon dioxide hydrate formation induced by synthesized Boehmite (AlOOH) nanoparticles was investigated at 274.15 K, different initial pressures (29, 32 and 35 bar), impeller speed (50, 100 and 200 rpm) and AlOOH concentrations (25, 50 75, 100, 200 ppm). It was also observed that there is a desirable concentration for AlOOH nanoparticles in which the maximum rate of gas consumption and minimum growth and induction time was obtained. According to the results at 29 bar and 100 rpm and in the presence of 50 ppm AlOOH, the gas consumption rate increased to 150%, while the induction time and growth time decreased about 82.8% and 46.1%, respectively. The maximum energy saving of 49.7% for 50 ppm AlOOH was observed, which is very important for industrial applications of carbon dioxide hydrate. The presented technique is useful for intensification of gas hydrate-based CO2 capture processes in the oil and gas industry with minimum energy consumption.

Reanalysis of discarded blastocysts for autosomal aneuploidy after sex selection in cleavage-stage embryos

Ebrahimian, Neda,Montazeri, Fatemeh,Sadeghi, Mohammad Reza,Kalantar, Seyed Mehdi,Gilany, Kambiz,Khalili, Mohannad Ali The Korean Society for Reproductive Medicine 2020 Clinical and Experimental Reproductive Medicine Vol.47 No.4

Objective: The goal of the present study was to investigate the rate of chromosomal aneuploidies in surplus embryos after sex determination at the cleavage stage. Then, the same chromosomal aneuploidies were evaluated in blastocysts after extended culture. Methods: Sixty-eight surplus embryos were biopsied at the cleavage stage and incubated for an additional 3 days to allow them to reach the blastocyst stage. The embryos were reanalyzed via fluorescence in situ hybridization (FISH) to examine eight chromosomes (13, 15, 16, 18, 21, 22, X, and Y) in both cleavage-stage embryos and blastocysts. Results: Although the total abnormality rate was lower in blastocysts (32.35%) than in cleavage-stage embryos (45.58%), the difference was not significant (p=0.113). However, when we restricted the analysis to autosomal abnormalities, we observed a significant difference in the abnormality rate between the cleavage-stage embryos (44.11%) and the blastocysts (17.64%, p=0.008). A higher rate of sex chromosomal abnormalities was also observed in cleavage-stage embryos (29.4%) than in blastocysts (14.70%, p=0.038). Conclusion: The data indicated that embryo biopsy should be conducted at the blastocyst stage rather than the cleavage stage. The results also emphasized that examination of common chromosomal aneuploidies apart from sex selection cycles can be conducted in the blastocyst stage with the FISH method.