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    TPU/graphene nanocomposites: effect of graphene functionality on the morphology of separated hard domains in thermoplastic polyurethane

    , Article Polymer ; Volume 148 , 18 July , 2018 , Pages 169-180 ; 00323861 (ISSN) Razeghi, M ; Pircheraghi, G ; Sharif University of Technology
    Elsevier Ltd  2018
    Abstract
    Graphene nanoplatelets with different surface functional groups and polarity were prepared by Hummer's method and electrochemical exfoliation of graphite in two aqueous acids. The XRD, FTIR and sedimentation tests performed to characterize the polarity of the prepared graphenes. The highest polarity was associated with the sample prepared by Hummer's method and the sample synthesized by electrochemical exfoliation in nitric acid medium showed the moderate polarity. Meanwhile, the sample prepared in sulfuric acid medium showed the lowest polarity. Then thermoplastic polyurethane (TPU)/graphene nanocomposite films were fabricated with solvent exchange method. While the dispersion state and... 

    ChemInform abstract: microwave-assisted rapid ketalization/acetalization of aromatic aldehydes and ketones in aqueous media [electronic resource]

    , Article Journal of Chemical Research ; September 1999, Volume -, Number 9; Page(s) 562 to 563 Pourdjavadi, A. (Ali) ; Mirjalili, Bibi Fatemeh ; Sharif University of Technology
    Abstract
    Aromatic aldehydes and ketones are readily acetalized or ketalized under microwave irradiation in the presence of water as a solvent  

    Synthesis and characterization of poly(methacrylates) containing spiroacetal and norbornene moieties in side chain [electronic resource]

    , Article Journal of Applied Polymer Science ; Volume 77, Issue 1, pages 30–38, 5 July 2000 Pourdjavadi, A. (Ali) ; Mirjalili, Bibi Fatemeh ; Sharif University of Technology
    Abstract
    A four-step synthetic strategy was applied to achieve novel methacrylic monomers. 5-Norbornene-2,2-dimethanol was prepared from a Diels–Alder reaction of cyclopentadiene and acrolein, followed by the treatment of the adduct with an HCHO/KOH/MeOH solution. The resulting 1,3-diol (1) was then acetalized with different aromatic aldehydes having OH groups on the ring to produce four spiroacetal derivatives. The reaction of methacryloyl chloride with the phenolic derivatives led to four new methacrylic monomers that were identified spectrochemically (mass, FTIR, 1H-NMR, and 13C-NMR spectroscopy). Free radical solution polymerization was used to prepare novel spiroacetal–norbornene containing... 

    Prediction of DNA/RNA Sequence Binding Site to Protein with the Ability to Implement on GPU

    , M.Sc. Thesis Sharif University of Technology Fatemeh Tabatabaei (Author) ; Koohi, Sommaye (Supervisor)
    Abstract
    Based on the importance of DNA/RNA binding proteins in different cellular processes, finding binding sites of them play crucial role in many applications, like designing drug/vaccine, designing protein, and cancer control. Many studies target this issue and try to improve the prediction accuracy with three strategies: complex neural-network structures, various types of inputs, and ML methods to extract input features. But due to the growing volume of sequences, these methods face serious processing challenges. So, this paper presents KDeep, based on CNN-LSTM and the primary form of DNA/RNA sequences as input. As the key feature improving the prediction accuracy, we propose a new encoding... 

    Investigate the Oscillations and Parameters of Bubble Induced by Laser in the Prescence of Acoustic Field

    , M.Sc. Thesis Sharif University of Technology Razeghi, Fatemeh (Author) ; Sadighi-Bonabi, Rasoul (Supervisor)
    Abstract
    Sonoluminescence is called a phenomenon in which a gas bubble is trapped in an antinode of a pressure field by a driven periodic acoustical field in a fluid and oscillations and at the end of each collapse, emits a flash. For this emission various conditions for stability must be satisfied, like diffusion stability, shape stability and positional stability. Another method to produce the bubbles is applications of a focused laser beam. In this method, a laser pulse is focused into a transparent buffer liquid like water and bubbles which are induced by the laser are so called Laser Induced Single Cavitation Bubble Luminescence (LI-SCBL). In the presence of the laser, the fluid acts as... 

    Study on the Exfoliation of Graphite into Graphene by Electrochemical Method and Its Application in Thermoplastic Polyurethane Nanocomposite

    , M.Sc. Thesis Sharif University of Technology Razeghi, Mohammad Ali (Author) ; Pircheraghi, Gholamreza (Supervisor)
    Abstract
    Graphene is two dimensional nanomaterial, single layer of carbon atoms that exhibited excellent properties like high electrical conductivity and stiffness, but producing graphene and obtaining a good dispersion of graphene in a polymer matrix is still a major challenge. In this study by using the electrochemical route several graphene with different degree of oxidation produced in different electrolyte medium. According to XRD data, product of electrochemical exfoliation in dilute HNO3 medium includes 50% few-layer graphene (5 layers) and 25% GO and the rest are multi-layer graphene. Nonsolvent induced phase separation method were used to prepare TPU/Graphene nanocomposite. Different methods... 

    Applying feature selection and machine learning techniques to estimate the biomass higher heating value

    , Article Scientific Reports ; Volume 13, Issue 1 , 2023 ; 20452322 (ISSN) Abdollahi, A ; Ranjbar, F ; Razeghi Jahromi, D ; Sharif University of Technology
    Nature Research  2023
    Abstract
    The biomass higher heating value (HHV) is an important thermal property that determines the amount of recoverable energy from agriculture byproducts. Precise laboratory measurement or accurate prediction of the HHV is essential for designing biomass conversion equipment. The current study combines feature selection scenarios and machine learning tools to establish a general model for estimating biomass HHV. Multiple linear regression and Pearson’s correlation coefficients justified that volatile matter, nitrogen, and oxygen content of biomass samples have a slight effect on the HHV and it is better to ignore them during the HHV modeling. Then, the prediction performance of random forest,... 

    Developing an Optimization Model for the Adaptation of Iran's Energy System to Climate Change

    , M.Sc. Thesis Sharif University of Technology Razeghi Jahromi, Dorsa (Author) ; Khajehpour, Hossein (Supervisor)
    Abstract
    This study develops an optimization model to assess and enhance the resilience of Iran’s energy system under future climate change conditions. Using the OSeMOSYS framework, the impacts of projected changes in temperature, precipitation, solar radiation, and wind speed on the performance of power generation technologies (solar, wind, hydro, and thermal) as well as on electricity demand patterns across Iran’s climatic regions were analyzed up to 2050. Four main scenarios were designed: (1) a baseline scenario without climate or environmental constraints, (2) an emission reduction scenario with carbon limits but no adaptation, (3) an adaptation scenario considering direct climatic effects on... 

    Correlation between trunk-pelvis inter-segmental coordination parameters during walking and disability level in chronic low back pain patients

    , Article Journal of Biomedical Physics and Engineering ; Volume 8, Issue 2 , 2018 , Pages 193-202 ; 22517200 (ISSN) Ebrahimi, S ; Kamali, F ; Razeghi, M ; Haghpanah, A ; Sharif University of Technology
    Shiraz University of Medical Sciences  2018
    Abstract
    Background: Chronic low back pain (CLBP) disability has been particularly frustrating because its treatment has been a great therapeutic challenge. Disability has been suggested to depend on different factors that should be found and considered in the medical management. The inter-segmental coordination is often impaired in CLBP subjects; however, to the best of our knowledge, there is no evidence about the relationship between the existence of coordination problems and disability in CLBP patients. Objective: To evaluate the correlation between sagittal plane trunk-pelvis intersegmental coordination parameters during walking and disability level in CLBP patients. Methods: Kinematic data were... 

    Cross-Lingual Speaker Adaptation for Statistical Parametric Speech Synthesis

    , M.Sc. Thesis Sharif University of Technology Saleh, Fatemeh Sadat (Author) ; Sameti, Hossein (Supervisor)
    Abstract
    Speech synthesis and its applications have been very attractive recently. The main purpose of this technique is to produce a speech signal with natural characteristics of human speech like prosody and emotion. Among all existing methods for speech synthesis, statistical parametric speech synthesis methods are more promising because ofhigher flexibility in comparison to other methods. One of the applications of speech synthesis is speech to speech translation. In these systems, the generated voice in target language should have the same characteristics as the input voice in source language. The main purpose of this research is to review and evaluate the cross lingual speaker adaptation... 

    Hydroelastic Analysis of Surface Piercing Propeller

    , M.Sc. Thesis Sharif University of Technology Fatemeh, Shahreki (Author) ; Seif, Mohamad Saeed (Supervisor)
    Abstract
    Surface piercing propellers are particular type of supercavitating propellers that are commonly used for High-speed vessels. Most studies on this type of propellers has been investigating the hydrodynamic forces. But in recent years with increase in SPPs diameter used in vessels, structural analysis of this type of propellers is considered. For this purpose, studies on the stresses exerted on the propeller structures under load is done with the help of Hydro elastic methods. In this type of analysis, structura of propeller is intended to be flexible and Displacements under pressure checked and Tensions resulting from it are studied.
    The present Thesis using ANSYS software to analyze a... 

    Data-Driven Pricing Based on Demand Prediction Using Machine Learning Methods

    , M.Sc. Thesis Sharif University of Technology Khosroshahi, Fatemeh Zahra (Author) ; Sedghi, Nafiseh (Supervisor)
    Abstract
    Pricing plays an important and essential role in the profit and income of companies. The importance of pricing is not only related to its role in the company's profitability, but it also changes the customer's understanding and loyalty towards the company and can create the company's reputation or destroy it. Determining the right price will increase product sales and increase customer loyalty and create a competitive advantage for the company. One of the most important and influential variables in product pricing is the amount of demand. The main challenge of companies for product pricing is the uncertainty in their demand. In order to deal with this problem, data-driven pricing is used.... 

    Design of Low-Power Zero Temperature Coefficient (ZTC) CMOS Oscillators

    , M.Sc. Thesis Sharif University of Technology Shahidani, Mohammad Aref (Author) ; Akbar, Fatemeh (Supervisor)
    Abstract
    The increasing demand for autonomous vehicles and reliable communication protocols and hardware interfaces, such as CAN bus and USB, underscores the necessity for stable clock sources that maintain a low temperature coefficient (TC) over wide temperature ranges. This demand is particularly emphasized in applications such as wearables, network sensors, downhole devices, WSNs, and IoT, where long-lasting battery life and frequency-stable clock sources over a broad temperature range (e.g. -20 °C to 100 °C) are crucial. Traditionally, variations in frequency caused by temperature have been mitigated by employing off-chip components like crystals or ceramic based oscillators, but this approach... 

    Design of Low Power Harmonic Rejection Mixer for Wideband Application

    , M.Sc. Thesis Sharif University of Technology Jafarpour Dahaghani, Reza (Author) ; Akbar, Fatemeh (Supervisor)
    Abstract
    The increasing demand for communication bandwidth and limited spectrum availability have heightened the complexity of radio front-end circuits in IoT applications. Achieving spectral efficiency is a key challenge, particularly for IoT devices operating at specific frequency bands such as 315 MHz, 433 MHz, 868 MHz, and 915 MHz.Due to the limited linearity of the transmit path, harmonic distortion components, known as counter intermodulation (CIM) products, are generated. These CIM products can directly fall into the receiver (RX) band or enter it via cross-modulation, thereby degrading the frequency division performance. Additionally, CIM products can interfere with protected bands, violating... 

    Silica chloride/wet SiO2 as a novel heterogeneous system for the deprotection of acetals under mild conditions [electronic resource]

    , Article Phosphorus, Sulfur, and Silicon and the Related Elements ; Volume 178:2667-2670, Issue 12, 2003 Mirjalili, B. F. (BiBi Fatemeh) ; Pourjavadi, Ali ; Zolfigol, Mohammad Ali ; Bamoniri, Abdolhamid
    Abstract
    A combination of silica chloride and wet SiO2 was used as an effective deacetalizating agent for the conversion of acetals to their corresponding carbonyl derivatives under mild and heterogeneous condition  

    The effect of viscosity, applied frequency and driven pressure on the laser induced bubble luminescence in water-sulfuric acid mixtures

    , Article Physics Letters, Section A: General, Atomic and Solid State Physics ; Volume 380, Issues 27–28 , June , 2016 , Pages 2219–2226 ; 03759601 (ISSN) Sadighi Bonabi, R ; Alijan Farzad Lahiji, F ; Razeghi, F ; Sharif University of Technology
    Elsevier  2016
    Abstract
    Production and oscillation of sonoluminescence bubbles by laser pulse in the presence of acoustic field in water and different concentrations of sulfuric acid are investigated. In the presence of acoustic field, the laser causes variable speed of sound, surface tension and density; and the host liquid acts as a compressible one and strongly affects the bubble's dynamics equations. The effect of various concentrations of sulfuric acid as a host liquid on the oscillation of bubble radius, bubble wall velocity and bubble interior temperature is studied. Furthermore, the effect of applied frequency on LI-SCBL in the presence of the acoustic field is investigated and an optimum sound wave... 

    Generating the Activation Patterns of the Leg Muscles during Human Locomotion Using the Central Pattern Generators as a Control Structure

    , Article Iranian Journal of Science and Technology - Transactions of Mechanical Engineering ; Volume 40, Issue 2 , 2016 , Pages 87-94 ; 22286187 (ISSN) Haghpanah, S. A ; Farahmand, F ; Zohoor, H ; Razeghi, M ; Sharif University of Technology
    Shiraz University  2016
    Abstract
    The central pattern generators have been considered as a method to simplify the control of the complex rhythmic motions, e.g., walking, by the central nervous system. In this study, a control structure was designed to control the soleus and tibialis anterior muscles in a complete gait cycle. The activation patterns of the muscles were measured experimentally and used as the reference signals of a tracking problem. The hip angle and ground reaction force were also used as a feedforward. The feedback from the Golgi tendon acted as a regulator of muscle activity. The controller was applied to two gait trials. The results indicated that the designed controller was capable of tracking the... 

    Comparison of the trunk-pelvis and lower extremities sagittal plane inter-segmental coordination and variability during walking in persons with and without chronic low back pain

    , Article Human Movement Science ; Volume 52 , 2017 , Pages 55-66 ; 01679457 (ISSN) Ebrahimi, S ; Kamali, F ; Razeghi, M ; Haghpanah, S. A ; Sharif University of Technology
    Elsevier B.V  2017
    Abstract
    Inter-segmental coordination can be influenced by chronic low back pain (CLBP). The sagittal plane lower extremities inter-segmental coordination pattern and variability, in conjunction with the pelvis and trunk, were assessed in subjects with and without non-specific CLBP during free-speed walking. Kinematic data were collected from 10 non-specific CLBP and 10 non-CLBP control volunteers while the subjects were walking at their preferred speed. Sagittal plane time-normalized segmental angles and velocities were used to calculate continuous relative phase for each data point. Mean absolute relative phase (MARP) and deviation phase (DP) were derived to quantify the trunk-pelvis and bilateral... 

    The Impact of AV and CAV Vehicles on Capacity and Traffic Flow with Cooperative Lane changing in Mixed Traffic Environment

    , M.Sc. Thesis Sharif University of Technology Zanjani, Fatemeh Sadat (Author) ; Nassiri, Habibollah (Supervisor)
    Abstract
    Autonomous vehicles, as an integral part of intelligent transportation systems, will play a significant role in the future of transportation services. These vehicles have a high potential to improve road traffic capacity and the efficiency of transportation systems. One type of autonomous vehicle is the connected and autonomous vehicle (CAV), which can communicate with each other, roadside units, traffic control signals, and other infrastructures or devices. This study investigates the impact of autonomous vehicles and connected and autonomous vehicles on the traffic flow of the Tehran-Karaj freeway and vice versa, under various penetration rates and in a mixed traffic environment. In this... 

    The Impact of Integrated Prediction and Optimization on the the Bullwhip Effect in supply chains

    , M.Sc. Thesis Sharif University of Technology Salavatizadeh, Fatemeh Zahra (Author) ; Sedghi, Nafiseh (Supervisor)
    Abstract
    The Bullwhip effect is a phenomenon that refers to the amplification of demand variance as one moves upstream in a supply chain. This effect imposes additional costs on the supply chain and complicates inventory planning. Several factors contribute to the emergence of this phenomenon, one of which is demand forecasting. Since the demand faced by each level of the supply chain is uncertain, every level must first forecast demand in order to plan its inventory and meet customer requirements. However, this very process of forecasting contributes to the bullwhip effect. In this study, we investigate the impact of machine learning and deep learning forecasting methods, along with their...