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Gearbox Vibrations Analysis for Noise Reduction through Computer Aided Engineering
, M.Sc. Thesis Sharif University of Technology ; Saadatfoumani, Mahmoud (Supervisor)
Abstract
Millions of people are exposed to vehicle noise at their work or residence environment daily and as a result their physical and mental healths get in danger. Subsequently the vehicle noise and vibration become an important factor in vehicle quality. Gearbox is a main element in vehicle powertrain and also an important source of noise and vibration. So inspection of vibration and noise in Gearbox and attempting to reduce it will help to reduce vehicle noise and vibration. This project is based on a deal between sharif university of technology and industry in which the target was to make improvement in every source of noise and vibration in a specific vehicle. The aim of this project is to...
Nonlinear Vibrations of Inclined Timoshenko Beam on Pasternak Foundation with Moving Force
, M.Sc. Thesis Sharif University of Technology ; Kargarnovin, Mohammad Hossein (Supervisor)
Abstract
In the first part of this thesis, the linear and nonlinear governing differential equations of motion of an inclined Euler-Bernoulli beam are used by tacking into account the effect of beam’s mid-plane stretching. Then nonlinear coupled governing partial differential equations of vibrations by including rotation of cross section, longitudinal and transverse displacements in the Timoshenko beam theory on Pasternak foundation under the act of moving concentrated force and as wll as moving mass are drived. To do this the energy method (Hamilton’s principle) based on the large deflection theory in conjuncture with the von-Karman relations is used. These equations are solved by applying...
Green synthesis of magnesium oxide nanoparticles and nanocomposites for photocatalytic antimicrobial, antibiofilm and antifungal applications
, Article Catalysts ; Volume 13, Issue 4 , 2023 ; 20734344 (ISSN) ; Farsadrooh, M ; Zare, I ; Gholami, A ; Akhavan, O ; Sharif University of Technology
MDPI
2023
Abstract
Magnesium oxide nanoparticles (MgO NPs) have emerged as potential materials for various biomedical applications due to their unique physicochemical properties, including biodegradability, biocompatibility, cationic capacity, high stability and redox properties. MgO NPs have become an attractive platform to combat microbes and may be a promising alternative to overcome challenges associated with eliminating microbial biofilms and antibiotic resistance. Hence, due to the increasing use of MgO NPs in biomedicine, new synthetic strategies for MgO NPs are necessary. MgO NPs synthesised using green methods are non-toxic, eco-friendly and have high stability for a wide range of biological, medical...
Design and Fabrication of Nanocamposite Scaffold for Neural Tissue Engineering
, M.Sc. Thesis Sharif University of Technology ; Ramazani Saadat Abadi , Ahmad (Supervisor) ; Neamati, ZiaratAli (Supervisor)
Abstract
Nervous system plays an intricate biological process of man body.Damage of nervous system has serious consequences and is hard to recover, as well as the other parts of the body may not work properly. Many strategies have been used to repair spinal cord injuries in which the main objective is to improve the regeneration of axons and functional recovery. The purpose of this research is introducing neural tissue engineering concepts (e.g. scaffolds, stimulation and etc.) and also design and fabrication suitable for neural tissue engineering. For this purpose the combination of biodegradable polymers (chitosan),conductive polymer (poly-aniline) and carbon nanosheets (graphene) was chosen as the...
Magneto-fluorescent contrast agents based on carbon Dots@Ferrite nanoparticles for tumor imaging
, Article Journal of Magnetism and Magnetic Materials ; Volume 561 , 2022 ; 03048853 (ISSN) ; Dehghani, H ; Angizi, S ; Ramedani, A ; Dolatyar, B ; Ramezani Farani, M ; Müllen, K ; Simchi, A ; Sharif University of Technology
Elsevier B.V
2022
Abstract
Bimodal magnetic-fluorescent materials for diagnostic imaging needs surface-engineered nanoparticles with great biosafety, pronounced colloidal stability, high magnetic moments, and strong photoluminescence (PL) emission. This work presents polymer-coated nanoparticles (PCNPs) based on manganese ferrites covered with a thin shell of nitrogen-doped carbon dots for magnetic-resonance and fluorescent dual mode imaging of cancerous tumors in vivo. An in situ thermolysis of metal oxalates and phenylenediamine in diphenyl ether allows for the facile synthesis of hybrid magneto-fluorescent nanoparticles. They possess an average size of 55 ± 5 nm with strong and excitation-independent PL emission at...
2D MXene nanocomposites: electrochemical and biomedical applications
, Article Environmental Science: Nano ; Volume 9, Issue 11 , 2022 , Pages 4038-4068 ; 20518153 (ISSN) ; Nourmohammadi Khiarak, B ; Tao, R ; Wang, Z ; Ahmadi, S ; Hassanpour, M ; Rabiee, M ; Saeb, M. R ; Lima, E. C ; Rabiee, N ; Sharif University of Technology
Royal Society of Chemistry
2022
Abstract
In recent years, key questions about the interaction of 2D MXene nanomaterials in electrochemical and biomedical applications have been raised. Most research has focused on clarifying the exclusive properties of the materials; however, only limited reports have described the biomedical applications of 2D nanomaterials. 2D MXenes are monolayer atomic nanosheets resulting from MAX phase ceramics. The hydrophilic properties, metallic conductivity, stability, and exclusive physiochemical performances make them promising materials for electrochemical and biomedical applications, including CO2 reduction, H2 evolution, energy conversion and storage, supercapacitors, stimuli-responsive drug delivery...
When pixels team up: Spatially weighted sparse coding for hyperspectral image classification
, Article IEEE Geoscience and Remote Sensing Letters ; Volume 12, Issue 1 , Jan , 2015 , Pages 107-111 ; 1545598X (ISSN) ; Rabiee, H. R ; Sharif University of Technology
Institute of Electrical and Electronics Engineers Inc
2015
Abstract
In this letter, a spatially weighted sparse unmixing approach is proposed as a front-end for hyperspectral image classification using a linear SVM. The idea is to partition the pixels of a hyperspectral image into a number of disjoint spatial neighborhoods. Since neighboring pixels are often composed of similar materials, their sparse codes are encouraged to have similar sparsity patterns. This is accomplished by means of a reweighted ℓ1 framework where it is assumed that fractional abundances of neighboring pixels are distributed according to a common Laplacian Scale Mixture (LSM) prior with a shared scale parameter. This shared parameter determines which endmembers contribute to the group...
Detecting Speakers in a Telephone Conversation
, M.Sc. Thesis Sharif University of Technology ; Sameti, Hossein (Supervisor)
Abstract
The human speech signal conveys many levels of information ranging from phonetic content to speaker identity and even emotional status. This thesis deals with the task of open-set speaker identification (SI) from an unconstrained telephone conversation between two speakers. The goal is to find at most two speakers among a known set of target speakers that best match the voice samples of the input speech; the input voice samples are not constrained to the target speaker set. The uni-speaker problem is investigated first. The classic GMM-UBM system for text-independent SI and its adapted form are explored. The use of score-space information is advocated as a complementary source to the...
Detection of dopamine receptors using nanoscale dendrimer for potential application in targeted delivery and whole-body imaging: synthesis and in vivo organ distribution
, Article ACS Applied Bio Materials ; Volume 5, Issue 4 , 2022 , Pages 1744-1755 ; 25766422 (ISSN) ; Aminzadeh Jahromi, N ; Ali, V ; Ebrahimpour, A ; Salehian, E ; Shafiee Ardestani, M ; Seyedhamzeh, M ; Ahmadi, S ; Sharifi, E ; Ashrafizadeh, M ; Rabiee, N ; Makvandi, P ; Sharif University of Technology
American Chemical Society
2022
Abstract
Dopamine is one of the most important neurotransmitters released by neurons in the central nervous system, and a variety of neurological illnesses and mental disorders are associated with impairments in the secretion and functionality of dopamine. Dopamine, depending on the type of receptors, can act as a stimulant or an inhibitor. In this study, dendrimer-conjugated dopamine was utilized as a chelating agent for Technetium-99m to investigate the organ distribution of this compound in vivo using the single-photon emission computed tomography (SPECT) technique. For this purpose, dendrimers were synthesized using polyethylene glycol diacid and citric acid precursors, and dopamine was...
Folic acid-adorned curcumin-loaded iron oxide nanoparticles for cervical cancer
, Article ACS Applied Bio Materials ; Volume 5, Issue 3 , 2022 , Pages 1305-1318 ; 25766422 (ISSN) ; Azarian, M ; Heydari Sheikh Hossein, H ; Abdolvahabi, Z ; Mohammadi Abgarmi, Z ; Moradi, A ; Mousavi, S. M ; Ashrafizadeh, M ; Makvandi, P ; Saeb, M. R ; Rabiee, N ; Sharif University of Technology
American Chemical Society
2022
Abstract
Cancer is a deadly disease that has long plagued humans and has become more prevalent in recent years. The common treatment modalities for this disease have always faced many problems and complications, and this has led to the discovery of strategies for cancer diagnosis and treatment. The use of magnetic nanoparticles in the past two decades has had a significant impact on this. One of the objectives of the present study is to introduce the special properties of these nanoparticles and how they are structured to load and transport drugs to tumors. In this study, iron oxide (Fe3O4) nanoparticles with 6 nm sizes were coated with hyperbranched polyglycerol (HPG) and folic acid (FA). The...
Engineered Biomimetic Membranes for Organ-on-a-Chip
, Article ACS Biomaterials Science and Engineering ; Volume 8, Issue 12 , 2022 , Pages 5038-5059 ; 23739878 (ISSN) ; Rasouli, F ; Jahangiri, S ; Ahmadi, S ; Rabiee, N ; Ramezani Farani, M ; Akhavan, O ; Asadnia, M ; Fatahi, Y ; Hong, S ; Lee, J ; Lee, J ; Hahn, S. K ; Sharif University of Technology
American Chemical Society
2022
Abstract
Organ-on-a-chip (OOC) systems are engineered nanobiosystems to mimic the physiochemical environment of a specific organ in the body. Among various components of OOC systems, biomimetic membranes have been regarded as one of the most important key components to develop controllable biomimetic bioanalysis systems. Here, we review the preparation and characterization of biomimetic membranes in comparison with the features of the extracellular matrix. After that, we review and discuss the latest applications of engineered biomimetic membranes to fabricate various organs on a chip, such as liver, kidney, intestine, lung, skin, heart, vasculature and blood vessels, brain, and multiorgans with...
Structured Sparse Representation for Machine Learning and Signal
Processing
,
Ph.D. Dissertation
Sharif University of Technology
;
Rabiei, Hamid Reza
(Supervisor)
Abstract
In this proposal we pursue structured sparse representations. Recent years have witnessed a tremendous growth in sparse modeling of natural signals. In this model a signal is represented as a linear combination of a few atoms from an often over-complete dictionary. The recent success of compressed sensing is intact due to the property that natural signals often admit sparse representations. Still, sparse representation in its simplest form sometimes fails to capture the intrinsic structure in natural signals. This structure may be embedded in the signal itself or in the relation between different signals of interest. The goal of this research proposal is to exploit the intrinsic structure in...
Development of a new classification system for assessing of carbonate rock sawability
, Article Archives of Mining Sciences ; Volume 56, Issue 1 , 2011 , Pages 59-70 ; 08607001 (ISSN) ; Yousefi, R ; Ataei, M ; Farani, R. A ; Sharif University of Technology
2011
Abstract
The prediction of rock sawability is very important in the cost estimation and the best planning of the plants. Rock sawability depends on the machine characteristics and rock mechanical properties. In this study, a new classification was developed with the respect to rock mechanical properties such as Uniaxial Compressive Strength, Brazilian tensile strength, Schmidt hammer value and Los Angeles abrasion loss. Using this system the carbonate rock sawability index (CRSi) of several types of carbonate rock was evaluated and classifi ed into fi ve categories and then a new model was developed with the respect to CRSi and machining characteristics by using the statistical analyses for...
Spatial-aware dictionary learning for hyperspectral image classification
, Article IEEE Transactions on Geoscience and Remote Sensing ; Volume 53, Issue 1 , July , 2015 , Pages 527-541 ; 01962892 (ISSN) ; Rabiee, H. R ; Hosseini, S. A ; Sharif University of Technology
Institute of Electrical and Electronics Engineers Inc
2015
Abstract
This paper presents a structured dictionary-based model for hyperspectral data that incorporates both spectral and contextual characteristics of spectral samples. The idea is to partition the pixels of a hyperspectral image into a number of spatial neighborhoods called contextual groups and to model the pixels inside a group as members of a common subspace. That is, each pixel is represented using a linear combination of a few dictionary elements learned from the data, but since pixels inside a contextual group are often made up of the same materials, their linear combinations are constrained to use common elements from the dictionary. To this end, dictionary learning is carried out with a...
Micropolar hypo-elasticity
, Article Archive of Applied Mechanics ; Volume 80, Issue 12 , December , 2010 , Pages 1449-1461 ; 09391533 (ISSN) ; Naghdabadi, R ; Sharif University of Technology
2010
Abstract
In this paper, the concept of hypo-elasticity is generalized to the micropolar continuum theory, and the general forms of the constitutive equations of the micropolar hypo-elastic materials are presented. A new co-rotational objective rate whose spin is the micropolar gyration tensor is introduced which describes the deformation of the material in view of an observer attached to the micro-structure. As special case, simplified versions of the proposed constitutive equations are given in which the same fourth-order elasticity tensors are used as in the micropolar linear elasticity. A 2-D finite element formulation for large elastic deformation of micropolar hypo-elastic media based on the...
Combined action of Casimir and electrostatic forces on nanocantilever arrays
, Article Acta Mechanica ; Volume 212, Issue 3-4 , July , 2010 , Pages 305-317 ; 00015970 (ISSN) ; Alasty, A ; Sharif University of Technology
2010
Abstract
Cantilever arrays with nearest-neighbor interactions are considered to obtain the pull-in parameters. The interactions between the neighboring beams are a combination of the Casimir force and the electrostatic force with the first-order fringing field correction. A set of coupled nonlinear boundary value problems and a set of coupled nonlinear equations arise in the distributed and lumped parameter modeling of the array, respectively. The models are simulated numerically to obtain the pull-in parameters of the arrays with different number of beams. The pull-in parameters of large arrays converge to constant values, which are independent of the number of beams in the array. The constants...
Comparison of supervised classification methods with various data preprocessing procedures for activation detection in fMRI data
, Article Springer Optimization and Its Applications ; Volume 38 , 2010 , Pages 75-83 ; 19316828 (ISSN) ; Fatemizadeh, E ; Sharif University of Technology
2010
Abstract
In this study we compare five classification methods for detecting activation in fMRI data: Fisher linear discriminant, support vector machine, Gaussian nave Bayes, correlation analysis and k-nearest neighbor classifier. In order to enhance classifiers performance a variety of data preprocessing steps were employed. The results show that although kNN and linear SVM can classify active and nonactive voxels with less than 1.2% error, careful preprocessing of the data, including dimensionality reduction, outlier elimination, and denoising are important factors in overall classification
Towards genetic feature selection in image steganalysis
, Article 2010 7th IEEE Consumer Communications and Networking Conference, CCNC 2010, 9 January 2010 through 12 January 2010, Las Vegas, NV ; 2010 ; 9781424451760 (ISBN) ; Ghaemmaghami, S ; Sharif University of Technology
2010
Abstract
In this study, a new feature-based steganalytic method is presented and four classification methods: Fisher Linear Discriminant, Gaussian naïve Bayes, Multilayer perceptron, and k nearest neighbor, are compared for steganalysis of suspicious images. The method exploits statistics of the histogram, wavelet statistics, amplitudes of local extrema from the 1D and 2D adjacency histograms, center of mass of the histogram characteristic function and co-occurrence matrices for feature extraction process. In order to reduce the proposed features dimension and select the best subset, genetic algorithm is used and the results are compared through principle component analysis and linear discriminant...
Adaptive image steganography with mod-4 embedding using image contrast
, Article 2010 7th IEEE Consumer Communications and Networking Conference, CCNC 2010, 9 January 2010 through 12 January 2010, Las Vegas, NV ; 2010 ; 9781424451760 (ISBN) ; Ghaemmaghami, S ; Sharif University of Technology
2010
Abstract
A new adaptive steganography method based on image contrast to improve the embedding capacity and imperceptibility of the stego images is presented. The method exploits the average difference between the gray level values of the pixels in 2x2 blocks of non-overlapping spatially and their mean gray level in order to select valid blocks for embedding. The method was tested on different gray scale images. Results show that our proposed approach provides larger embedding capacity, while being less detectable by steganalysis methods such as χ2 attack and machine learning steganalysis systems, as compared to some well-known adaptive and non-adaptive steganography algorithms
Multigrid convergence acceleration for implicit and explicit solution of Euler equations on unstructured grids
, Article International Journal for Numerical Methods in Fluids ; Volume 62, Issue 9 , 2010 , Pages 994-1012 ; 02712091 (ISSN) ; Mazaheri, K ; Sharif University of Technology
2010
Abstract
The multigrid method is one of the most efficient techniques for convergence acceleration of iterative methods. In this method, a grid coarsening algorithm is required. Here, an agglomeration scheme is introduced, which is applicable in both cell-center and cell-vertex 2 and 3D discretizations. A new implicit formulation is presented, which results in better computation efficiency, when added to the multigrid scheme. A few simple procedures are also proposed and applied to provide even higher convergence acceleration. The Euler equations are solved on an unstructured grid around standard transonic configurations to validate the algorithm and to assess its superiority to conventional explicit...