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Modeling of self-controlling hyperthermia based on nickel alloy ferrofluids: Proposition of new nanoparticles
, Article Journal of Magnetism and Magnetic Materials ; Volume 335 , 2013 , Pages 59-63 ; 03048853 (ISSN) ; Madaah Hosseini, H. R ; Wolff, M ; Sharif University of Technology
2013
Abstract
In order to provide sufficient heat without overheating healthy tissue in magnetic fluid hyperthermia (MFH), a careful design of the magnetic properties of nanoparticles is essential. We perform a systematic calculation of magnetic properties of Ni-alloy nanoparticles. Stoner-Wohlfarth model based theories (SWMBTs) are considered and the linear response theory (LRT) is used to extract the hysteresis loop of nickel alloy nanoparticles in alternating magnetic fields. It is demonstrated that in the safe range of magnetic field intensity and frequency the LRT cannot be used for the calculation of the area in the hysteresis for magnetic fields relevant for hyperthermia. The best composition and...
Effects of particle size, shape and crystal structure on the formation energy of Schottky vacancies in free-standing metal nanoparticles: A model study
, Article Physica B: Condensed Matter ; Volume 406, Issue 20 , October , 2011 , Pages 3777-3780 ; 09214526 (ISSN) ; Madaah Hosseini, H. R ; Simchi, A ; Sharif University of Technology
2011
Abstract
A simplified model based on cohesive energy is proposed to estimate the formation energy of Schottky vacancies (VFE) in free-standing metal nanoparticles with BCC and FCC crystal structures. To study the effect of particle size and shape, the surface energy, elastic contraction and average coordination number of particles at the surface and core was considered. It is shown that the energy of vacancy formation in FCC nanoparticles increases with decreasing the size while the effect of particle shape (sphere, cubic and icosahedral) is marginal. In spite of this behavior, BCC nanoparticles exhibit a critical particle size at around 25 Å, at which a minimum VFE is attained. Additionally, the...
Adaptive second-order fractional sliding mode control with application to water tanks level control
, Article Fractional Calculus: Applications ; 2015 , Pages 149-163 ; 9781634632331 (ISBN)9781634632218 (ISBN) ; Faieghi, M ; Delavari, H ; Sharif University of Technology
Nova Science Publishers, Inc
2015
Abstract
Combining the fractional calculus with second-order sliding mode control,a novel type of control strategycalled second order fractional sliding mode control is introduced for a class of nonlinear dynamical systemssubject to uncertainty. A fractional-order switching manifold is proposed and the corresponding control law isformulated based on the Lyapunov stability theory to guarantee the sliding condition. A novel adaptation algorithm is derived to ensure perfect tracking, diminish chattering effect and steady state error by estimating switching controller parameters. Finally, numerical simulation results utilizing the dynamic model of interconnected twin tank system are presented to...
A study on the concentration-dependent relaxometric transition in manganese oxide nanocolloid as mri contrast agent
, Article ChemistrySelect ; Volume 4, Issue 25 , 2019 , Pages 7596-7601 ; 23656549 (ISSN) ; Malek, M ; Hosseini, H. R. M ; Delavari H, H ; Vahdatkhah, P ; Sharif University of Technology
Wiley-Blackwell
2019
Abstract
A green precipitation method has been used for the synthesis of ultra-small APTMS-mPEG conjugated Mn3O4 nanoparticles. Spherical cores in the uniform size of 4±1 nm were characterized by HRTEM. Zeta potential of −45 mV and the invariant turbidimetry results during the time, confirmed super-stability of the colloids. MRI relaxometry by 1.5 T scanner represented two values of r1= 8.23 s−1mM−1 and r1=7.3 s−1mM−1 for diluted and concentrated samples. The r2/r1 ratio was also decreased from 11.86 to 6.9 by dilution of colloids. Particle aggregation and motional narrowing phenomena led to a dual T1/T2 contrast agent in the Mn ion concentrations of more than 0.2 mM. The optimum concentration of Mn...
A simple model for the size and shape dependent Curie temperature of freestanding Ni and Fe nanoparticles based on the average coordination number and atomic cohesive energy
, Article Chemical Physics ; Volume 383, Issue 1-3 , 2011 , Pages 1-5 ; 03010104 (ISSN) ; Madaah Hosseini, H ; Simchi, A ; Sharif University of Technology
2011
Abstract
To study the effect of size and shape of metallic nanoparticle on their Curie temperature, an analytical model is proposed. The core average coordination number (CAC) and surface average coordination number (SAC) of freestanding nanoparticles are considered in the model. Clusters of icosahedral (IC) and body centred cubic (BCC) structure without any vacancies and defects are modelled. A critical Curie temperature is introduced for metallic clusters with a diameter of 2-3 nm. This critical diameter is related to clusters which the ratio of surface atoms to total atoms is about 50%. The "shape effect" is shown to be important at sizes less than 20 nm. The obtained results are supported by...
Magnetic domain regime-controlled synthesis of nickel nano-particles by applying statistical experimental design in modified polyol process
, Article Materials Chemistry and Physics ; Volume 168 , 2015 , Pages 117-121 ; 02540584 (ISSN) ; Madaah Hosseini, H. R ; Wolff, M ; Sharif University of Technology
Elsevier Ltd
2015
Abstract
In this work, central composite design (CCD) as a statistical experimental design method is performed to prepare nickel nano-particle of different magnetic domain regimes by the modified polyol process. It is shown that not only the concentration of the different chemicals but also the injection rate is determining for the morphology and magnetic properties. The average diameter of the synthesized nickel NPs is smaller than the critical single domain size and thus the single domain or pseudo-single domain nickel nano-particles can be prepared based on Day's plot
Rapid microwave-assisted synthesis of PVP-coated ultrasmall gadolinium oxide nanoparticles for magnetic resonance imaging
, Article Chemical Physics ; Volume 453-454 , May , 2015 , Pages 35-41 ; 03010104 (ISSN) ; Madaah Hosseini, H. R ; Khodaei, A ; Montazerabadi, A. R ; Irajirad, R ; Oghabian, M. A ; Delavari,H. H ; Sharif University of Technology
Elsevier
2015
Abstract
Synthesis of polyvinyl pyrrolidone (PVP) coated ultrasmall Gd2 O3 nanoparticles (NPs) with enhanced T1 -weighted signal intensity and r2 /r1 ratio close to unity is performed by a microwave-assisted polyol process. PVP coated Gd2 O3 NPs with spherical shape and uniform size of 2.5 ± 0.5 nm have been synthesized below 5 min and structure and morphology confirmed by HRTEM, XRD and FTIR. The longitudinal (r1 ) and transversal relaxation (r2 ) of Gd2 O3 NPs is measured by a 3 T MRI scanner. The results showed considerable increasing of relaxivity for Gd2 O3 NPs in...
Evaluating Impact of Erasure Codes on Performance and Endurance of SSD-Based RAID Array
, M.Sc. Thesis Sharif University of Technology ; Asadi, Hossein (Supervisor)
Abstract
Performance and reliability are the major concerns in design of data storage systems. Using Redundant Array of Independent Disks (RAID) can enhance both performance and reliability. A commonly used configuration in RAID arrays is erasure codes to further enhance system reliability. Due to promising advantages of Solid-State Drives (SSDs)such as low power, shock resistance, and high I/O performance, designers have been encouraged to replace Hard Disk Drives (HDDs) by SSDs in RAID arrays. SSDs, however, suffer from limited endurance due to erase-before-write operation.In this thesis, we investigate the effect of stripe unite size and the number of disks of a RAID array on the endurance of SSDs...
Integration Operation Management for Outpatient Clinics Case Study: Milad Hospital
,
M.Sc. Thesis
Sharif University of Technology
;
Eshghi, Kourosh
(Supervisor)
;
Delavari, Vahid
(Supervisor)
Abstract
Outpatient clinics always encounter a huge deal of demand and due to the variety of the services they provide and the existence of uncertainties, operation management is such a difficult task. This issue has made problems related to this issue popular among scientists and researchers. In this research, we are going to address several popular problems related to outpatient appointment scheduling. Initially, an M/M/c/K queuing system is developed in order to obtain the optimum scheduling window for different sub clinics. Secondly, the real demand for each sub clinics will be estimated using data analysis techniques for each 24-hour period. Having the results of the previous section, we build a...
An Optimization Model for Designing an Appointment-Making Procedure for Outpatients–Case Study: Milad Hospital Clinic
, M.Sc. Thesis Sharif University of Technology ; Eshghi, Kourosh (Supervisor) ; Delavari, Vahid (Co-Supervisor)
Abstract
Patient scheduling is one of the most important problems in healthcare optimization which has been in center of attention in various environments including outpatient clinics and operating rooms. Effective scheduling systems have the goal of matching the demand with capacity so that resources are better utilized and patient waiting times are minimized. Furthermore, patient scheduling can be merged with another problem in which the main goal is to find the optimal sequence of a given list of patients. Moreover, there are several sources of uncertainty such as patients’ unpunctuality, absence, and service time in this problem resulting in having a very complex problem. In this research,...
Nonlinear interstory drift contours for idealized forward directivity pulses using "modified fish-bone" models
, Article Advances in Structural Engineering ; Volume 18, Issue 5 , May , 2015 , Pages 603-627 ; 13694332 (ISSN) ; Khosravi, H ; Jamnani, H. H ; Sharif University of Technology
Multi-Science Publishing Co. Ltd
2015
Abstract
Four 5-, 10-, 20- and 30-story moment frames, representing low-, mid-, and two high-rise structures, were subjected to a great number of idealized directivity pulses. The amplitudes and periods of pulses vary from 0.02 g to 1.0 g and 0.5 to 12 sec, respectively. Over 1400 nonlinear dynamic analyses of low- to high-rise moment frames were performed which were feasible through using modified fish-bone model. The distribution of interstory drift along the height was studied and two applied contours were proposed: (i) the maximum interstory drift contour, and (ii) the critical story contour. These contours were demonstrated versus the ratio of natural period of the structure to the pulse period...
Analysis of singularities of a 3DOF parallel manipulator based on a novel geometrical method
, Article 8th Biennial ASME Conference on Engineering Systems Design and Analysis, ESDA2006, Torino, 4 July 2006 through 7 July 2006 ; Volume 2006 , 2006 ; 0791837793 (ISBN); 9780791837795 (ISBN) ; Sadeghian, H ; Roozbehani, H ; Zohoor, H ; Sharif University of Technology
2006
Abstract
In this article singular points of a parallel manipulator are obtained based on a novel geometrical method. Here we introduce the constrained plain method (CPM) and some of its application in parallel mechanism. Given the definition of constraint plane (CP) and infinite constraint plane (ICP) the dependency conditions of constraints is achieved with the use of a new theorem based on the Ceva geometrical theorem. The direction of angular velocity of a body is achieved by having three ICPs with the use of another theorem. Finally, with the use of the above two novel theorems singularities of the 3UPF_PU mechanism are obtained. It should be emphasized that this method is completely geometrical,...
Design and Implementation of an Intelligent UVC Disinfection Robot based on IoT Technology
, Article 7th International Conference on Internet of Things and Applications, IoT 2023 ; 2023 ; 979-835036941-0 (ISBN) ; Naderian, S ; Roshanaei, M ; Ashrafs, M. G ; Kiani, S ; Torkashvand, M ; Sharif University of Technology
Institute of Electrical and Electronics Engineers Inc
2023
Abstract
In this paper, an intelligent UV disinfection robot based on Internet of Things (IoT) technology is proposed. The proposed method is used to reduce human operator roles and risks with the help of IoT based monitoring of the robot. The intelligent disinfection robot consists of two important parts. The first one is the mobile robot which is controlled remotely and wirelessly based on Raspberry Pi 3 Model B+ as a wireless microcontroller. Furthermore, Passive Infrared (PIR) and Ultrasonic sensors are installed on the mobile robot to detect human presence and obstacles, respectively. The second one is a tower unit that contains four ultraviolet-type C (UVC) lamps and a Raspberry Pi camera. The...
Melting enthalpy and entropy of freestanding metallic nanoparticles based on cohesive energy and average coordination number
, Article Journal of Physical Chemistry C ; Volume 115, Issue 35 , August , 2011 , Pages 17310-17313 ; 19327447 (ISSN) ; Delavari H., H ; Madaah Hosseini, H. R ; Sharif University of Technology
2011
Abstract
An analytical model is proposed to study the effect of particle size on melting enthalpy and entropy of metallic nanoparticles (NPs). The Mott's and Regel's equations for melting entropy in the combination of core average coordination number (CAC) and surface average coordination number (SAC) of freestanding NPs are considered. Clusters of icosahedral (IC), body centered cubic (BCC), and body centered tetragonal (BCT) structure without any vacancies and defects are modeled. Using the variable coordination number made this model to be in good agreement with experimental and molecular dynamic (MD) results of different crystal structures. The model predicts melting entropy and enthalpy of...
On the temperature and residual stress field during grinding
, Article WCE 2010 - World Congress on Engineering 2010, 30 June 2010 through 2 July 2010 ; Volume 2 , 2010 , Pages 1196-1200 ; 9789881821072 (ISBN) ; Farrahi, G. H ; Ghadbeigi, H ; Sharif University of Technology
2010
Abstract
Grinding is widely used for manufacturing of components that require fine surface finish and good dimensional accuracy. In this study a thermo-mechanical finite element analysis is conducted to find out how grinding parameters can affect temperature and residual stress distribution in the workpiece. Results of parametric study presented in this work indicate, by carefully selecting the grinding parameters, minimum thermal and mechanical damage can be achieved. Higher workpiece velocities produce higher surface residual stress. By increasing depths of cut, depth of tensile residual stresses increases. Convection heat coefficient does not have any considerable effect on surface residual stress...
A new lattic LP-based post filter for adaptive noise cancellers in mobile and vehicular applications
, Article Proceedings of the 8th IEEE International Symposium on Signal Processing and Information Technology, ISSPIT 2008, 16 December 2008 through 19 December 2008, Sarajevo ; 2008 , Pages 407-412 ; 9781424435555 (ISBN) ; Sameti, H ; Veisi, H ; Abutalebi, H. R ; Sharif University of Technology
2008
Abstract
Adaptive Noise Cancellation (ANC) is a well-known technique for background noise reduction in automobile and vehicular environments. The noise fields in automobile and other vehicle interior obey the diffuse noise field model closely. On the other hand, the ANC does not provide sufficient noise reduction in the diffuse noise fields. In this paper, a new multistage post-filter is designed for ANC as a solution to diffuse noise conditions. The designed post-filter is a single channel Linear Prediction (LP) based speech enhancement system. The LP is performed by an adaptive lattice filter and attempts to extract speech components by using intermediate ANC signals. The post-filter has no...
Finite element analysis of shot-peening effect on fretting fatigue parameters
, Article Tribology International ; Volume 44, Issue 11 , 2011 , Pages 1583-1588 ; 0301679X (ISSN) ; Alvandi Tabrizi, Y ; Farrahi, G. H ; Majzoobi, G. H ; Ghadbeigi, H ; Sharif University of Technology
2011
Abstract
Shot peening is widely used to improve the fretting fatigue strength of critical surfaces. Fretting fatigue occurs in contacting parts that are subjected to fluctuating loads and sliding movements at the same time. This paper presents a sequential finite element simulation to investigate the shot peening effects on normal stress, shear stress, bulk stress and slip amplitude, which are considered to be the controlling parameters of fretting damage. The results demonstrated that among the modifications related to shot peening, compressive residual stress has a dominant effect on the fretting parameters
Mechanically activated synthesis of single crystalline MgO nanostructures
, Article Journal of Alloys and Compounds ; Volume 506, Issue 2 , September , 2010 , Pages 715-720 ; 09258388 (ISSN) ; Yoozbashizadeh, H ; Askari, M ; Kobatake, H ; Fukuyama, H ; Sharif University of Technology
2010
Abstract
One-dimensional (1D) MgO structures were successfully synthesized via carbothermic reduction of mechanically activated mixture of MgO and graphite. Mechanical activation of source materials before carbothermic reduction can substantially enhance the formation of MgO products at a temperature (1000 °C) relatively lower than that required in previous approaches (≥1200 °C). However, the morphology of MgO formed is dependent on the degree of mechanical activation and the condition of the subsequent carbothermic reduction. Two distinctive morphologies were found for MgO products synthesized using our method: single crystalline nanorods with rectangular cross-sections whose diameters range from 50...
Boundary control design for vibration suppression and attitude control of flexible satellites with multi-section appendages
, Article Acta Astronautica ; Volume 173 , 2020 , Pages 22-30 ; Salarieh, H ; Nejat Pishkenari, H ; Jalili, H ; Sharif University of Technology
Elsevier Ltd
2020
Abstract
Attitude and vibration control of a general form of flexible satellites is addressed in this paper. Partial differential dynamic equations are derived considering new details such as multi sectioned solar panels and elastic connections between main hub and solar panels. Boundary control approach is adopted to eliminate simplification errors of discrete models, using just one actuator in the hub. Asymptotic stability of attitude dynamics is proved for a group of boundary controllers and necessary conditions for asymptotic stability of vibrations are discussed. Being independent of modeling accuracy and using easily measurable feedbacks are among advantages of the proposed class of...
Characterization and calcination behavior of a low-grade manganese ore
, Article Materials Today Communications ; Volume 25 , 2020 ; Becker, H ; Eftekhari, H ; Yoozbashizadeh, H ; Safarian, J ; Sharif University of Technology
Elsevier Ltd
2020
Abstract
Characterization and calcination behavior of a low-grade manganese ore, as a part of Mn ferroalloys production, was studied by XRF, ex-situ XRD, in-situ XRD, and SEM-EDS techniques. Calcination experiments were carried out at and up to 900 °C (1173 K) in air and argon atmospheres. The samples were in particles and powder forms. The results indicated that both quartz and calcite phases in the ore exhibit a bimodal spatial distribution; as relatively large regions and finely distributed in the Mn- and Fe-containing phases. By Rietveld analysis of the in-situ XRD data, the reactions occurring upon heating during the calcination process were deduced. Thermal decomposition and reactive diffusion...