Sharif Digital Repository

Minimally Invasive Surgery (MIS) is a modern surgical technique in which the operation is performed through small incisions in the body. Therefore, the surgeon looses his/her sense of touch which is of high importance in any medical operation. In the present work, a novel smart grasper is presented in which the surgeon can virtually acquire a feeling of force/momentum experienced by the organ/tissue. The smart grasper uses piezoelectric sensors bonded at desired locations to detect the applied force/momentum applied by surgeon and to measure the transmitted force/momentum to the tissue/organ. First, an accurate electro-mechanical model of the smart grasper is developed and the relations... 

Platinum nanotubes were deposited inside the pores of polycarbonate template with the pore size of 200 nm by electrochemical methods. In this regard a solution containing of 0.05 M H2PtCl6 and 0. 1 M H2SO4 in doubly distilled water was utilized. The electrodeposition process was studied by electrochemical techniques such as voltammetry and chronoamperometry methods. It was observed that the process was conducted in several stages including; nucleation and growth in steady state regime. Furthermore, it was concluded that electrodeposition was affected by mass transport restriction and was controlled by a diffusion process. In this regard, all the voltammograms were shifted to more negative... 

Wireless sensor networks have a wide range of applications in the world. In most of the applications, collected data is not usable without the knowledge about the localization of events. There are two approaches to specifying the location of a sensor: using hardware solutions such as GPS, which is an expensive solution, and using the localization algorithm. Therefore, localization has an important role in sensor networks. Most of the current localization algorithms are non-adaptive and proposed for fixed wireless sensor networks. Recently, adaptive localization algorithms have been considered because of their simple implementation, fast result and low computation overhead for each node. In... 

Nowadays, fiber sensors have lots of usage in complicated structure and oil industries. There is some ways for leak detection in pipelines to low the cost of damage. One of the best is using the distributed fiber sensors for monitoring and detection of leakage in pipelines because of their ability to accuracy measurment. The leakage produces some kind of acostic wave that affect on fiber optic as a stress. There is lot of methodes to measure the location of stress in fiber. One of them is measuring the polarization mode coupling. A polarization diversity detection system for location of polarization mode coupling has been studied both theoretically and experimentally for use with... 

Design and construction of an optical fiber sensor for liquid concentration detection are reported. This sensor operates based on light intensity modulation.Such modulation results from alteration of total internal reflection into partial reflection at the interface. It is well known that the extinction ratio is varied by changing the concentration.In this system,two optical fiber swere used, one transmitting the light source, another acting as the receiving fiber and a glass prism providing the total and partial reflections. The modulated intensity has been measured by using a receiving fiber. During the concentration measurements, when a liquid in a vessel touches the 45° faces of the... 

Nowadays, many offshore jacket platforms have been built in all over the world for excavating oil and gas. Due to cost of construction and maintenance, they are considered as national assets. Jacket platforms are always under various types of loads in their time life, so they cause some damages to them. Hence, on time damage detection can prevent possible extravagant costs of repair and reconstruction. Because many jacket platforms are in Iran, this issue can be very important.Structural health monitoring (SHM) improvised to ensure safety and detect damages of structures uses sensors. They transfer data received from structures to the computers in order that after interpretation of data,... 

In this thesis selection criteria are present for types, numbers and locations of sensors for structural health monitoring of offshore jacket platform in the Persian Gulf. The selection criteria are chosen by studying structural health monitoring of various structures in civil and aerospace industries. Knowing the types of sensors that can be used, a new approach of inverse vibration problem is introduced for structural health monitoring of offshore jacket platforms. In the previous studies, significant numbers of frequencies and mode shapes are usually used to detect damages by updating components of stiffness matrix. Considering the fact that offshore platforms are composed of a heavy... 

Electrochemical sensing of glucose has received paramount attention in recent years, particularly, the non-enzymatic glucose sensing is one of the trends in the whole biosensing world. In this research, synthesis and evaluation of a hybrid structure of vertical oriented nickel nanorod-reduced graphene oxide sheets as a non-enzymatic glucose sensor were performed. The 3D array of nickel nanorods was synthesized by electrodeposition of nickel sulfate electrolyte in track-etched polycarbonate template with 100 nm pore size and 6-10 μm thickness. The electrodeposition performed in various conditions, and the best result was achieved by application of potential of 3 V for 60 minutes. The shiny... 

Bias Temperature Instability (BTI) is known as one serious reliability concern in nanoscale technology sizes. BTI gradually degrades threshold voltage (Vth) of MOS transistors. The main consequence of Vth degradation in SRAM cell transistors is the Static Noise Margin (SNM) degradation that makes SRAM cells susceptible against soft errors. SNM degradation in SRAM cells results in bit-flip occurrences and should be monitored accurately before resulting in permanent failures. This work proposes a sensor called Current-based BTI Sensor (CBS) to assess the aging state of SRAM cells. CBS measures BTI-induced SNM degradation of SRAM cells by monitoring the write current shifts due to BTI. The... 

The propagation of love waves in a one-layered piezoelectric medium with slightly curved boundaries of sinusoidal type have been investigated in this study. Because of the widespread use of piezoelectric materials as surface acoustic wave (SAW) devices, sensors, actuators and in vibration control, the study of Love wave propagation in this Medias has been in the forefront of present studies in this era. But there always will be imperfection on surfaces. By employing the Taylor expansion up to the first order and using perturbation technic on the case with no irregularity and solving the problem, it has been found that along with the usual displacement components for stratified boundaries,... 

In this dissertation a new approach is introduced for damage detection in offshore jacket platforms. The procedure uses the measured ambient vibration responses and the corresponding readable natural frequencies and mode shapes of the structural systems. Since offshore platforms are composed of heavy topsides supported by jacket structures, participation of the first mode is dominant in each direction in the response of the structure under field excitations. Moreover, ambient vibrations such as wave loads and boat impacts only excite the first modes of the structure. Therefore, it is difficult to find higher modes and the pertinent frequencies by use of accelerometers data. The introduced... 

In recent years, molecular communications have received considerable attentions for communication between nano-machines. In this communication scheme, which uses molecules as information carriers, nano transmitter and receiver are in distance apart of nano meter to meter and information is encoded into type, concentration or releasing time of molecules. Since nano transmitter and receiver can do very simple operations, such as adding, sensing, and etc., for more complicated operations, a network of nano transceivers is required. In this thesis, a small scale imaging of an abnormality in the environment is investigated. To this end, a network of sensors is assumed to be placed in the... 

Identifying driving behaviors and building an efficient and accurate driving behavior recognition model is of paramount importance for improving driving safety. Nowadays, with the ubiquity of smartphone sensors, many researchers are using smartphone sensory data to create models which forecast driving behaviors. This research introduces a logit model that predicts nine types of driving events using accelerometer and gyroscope sensors with an accuracy of 76 percent  

A significant number of small-scale sensor sales have been reported in recent years. Strain gauges are one of the most common tools for measuring the length change of a part. Nowadays, 3D printing technology can be used in the fabrication of small-scale sensitive sensors, and metal nanoparticles printing are especially suitable for the production of flexible electronic sensors. Electro-hydrodynamic printer, with micro-scale printing capabilities, can be used as a new invention in fabrication of sensors. This type of printer uses the inkjet printing method and the basis of this type of printer is to apply an electric field to shrink the fluid jet. In the present study, pure ethanol was first... 

Sensors are one of the most vital instruments in Nuclear Power Plants (NPP), and operators and safety systems monitor various parts of the NPP and control transients by analyzing the values reported by the sensors. Failure to detect malfunctions or anomalies in them would lead to catastrophic consequences. A new approach based on thermo-hydraulic simulation by RELAP5 code and Feed-Forward Neural Networks (FFNN) is given to detect faulty sensors and estimate their correct value which are two main objectives of the current study. This approach consists of two main parts; The first part, Fault Detection Hyper Block (FDHB), responsible for detecting faulty sensors, and the second part,... 

The use of the Internet of Things in buildings has become increasingly important. Meanwhile, sensors and actuators play a very important role. With the help of sensors, various data of residents' environment and behavior can be obtained and various parameters can be controlled through actuators. Data from the presence, measurement and decision making of the components of this structure in a building can be used to model and predict the behavior of residents with methods of machine learning, data mining and artificial intelligence such as deep learning and Gaussian processes, helping to achieve the goal of residents' comfort and energy saving.In the desired structure, the sensor- actuator...