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Articles 2491 - 2520 of 3180

Full-Text Articles in Engineering

A Tutorial On Lte Evolved Utran (Eutran) And Lte Self Organizing Networks (Son), Dhruv Sunil Shah Jan 2010

A Tutorial On Lte Evolved Utran (Eutran) And Lte Self Organizing Networks (Son), Dhruv Sunil Shah

Electrical Engineering Theses - Archive

The third-generation (3G) cellular communication technology, Universal Mobile Terrestrial System (UMTS), based on Wideband Code-Division Multiple Access (WCDMA), has been widely deployed all over the world providing faster download speeds for data (packet) communications. To further improve the throughput and overall performance of the cellular communication system established by UMTS, the Third Generation Partnership Project (3GPP) in November 2004 launched an ambitious project called the Long Term Evolution (LTE) of UMTS. This would ensure the continued competitiveness of the UMTS in the future. The technical specifications of the LTE project are formally known as the Evolved UMTS Terrestrial Radio Access …

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Detection And Severity Classification Of Rotor Imbalance Faults In Induction Machines, Himanshu Jain Jan 2010

Detection And Severity Classification Of Rotor Imbalance Faults In Induction Machines, Himanshu Jain

Electrical Engineering Theses - Archive

As world economy continues to globalize, increased competition has lead to a reduction in profit margins. To remain competitive in such an economy, an industry needs to reduce the downtime of critical components even for maintenance purposes. However, this should not jeopardize the genuine maintenance needs of the equipments. In other words, an optimized maintenance strategy is needed, in which maintenance is performed only when a need for it arises; unlike the currently popular periodic maintenance. Condition based Maintenance (CBM) is one such strategy. Induction machines are work horse of an industry. Their criticality to industry may be gauged by …

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Mems Piezoresistive Pressure Sensor On Flexible Substrates Using Nichrome And Cnt/Polyimide Nanocomposites Piezoresistors, Gaviraj Nadvi Jan 2010

Mems Piezoresistive Pressure Sensor On Flexible Substrates Using Nichrome And Cnt/Polyimide Nanocomposites Piezoresistors, Gaviraj Nadvi

Electrical Engineering Theses - Archive

Micro pressure sensors using nichrome as piezoresistor were fabricated on silicon and flexible substrates. The pressure sensors on flexible substrate can be used for prosthetic skin applications. The devices were successfully tested using different methods.Micromachined pressure/force sensors using nickel chromium piezoresistors have been investigated experimentally and through finite element mesh analysis. The pressure/force sensors were designed using a suspended aluminum oxide membrane with optimally placed piezoresistors to measure the strain in the membrane when deflected with an applied force or pressure. Different devices, each with varying size and shape of both the membrane and the piezoresistors were designed, fabricated, and …

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Low Complexity H.264 To Vc-1 Transcoder, Vidhya Vijayakumar Jan 2010

Low Complexity H.264 To Vc-1 Transcoder, Vidhya Vijayakumar

Electrical Engineering Theses - Archive

The high definition video adoption has been growing rapidly for the last five years. The H.264 and VC-1 coding standards are two of the recent and dominant coding standards. Compared to H.264, VC-1 is less complex but capable of achieving the same visual quality as H.264. Hence there is increasing importance of techniques which can convert video from H.264 to VC-1 and thereby enable mobile devices to work with less complex codecs. While there has been recent work on VC-1 to H.264 transcoding, the published work on H.264 to VC-1 transcoding is nearly non-existent. This has created the motivation to …

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An Ultra Wide Band Cmos Low Noise Amplifier Design, Nahusha Bhadravati Mohankumar Jan 2010

An Ultra Wide Band Cmos Low Noise Amplifier Design, Nahusha Bhadravati Mohankumar

Electrical Engineering Theses - Archive

An RF ultra wide band low noise amplifier designed for the frequency range of 12-18 GHz of operation is presented in this paper. The low noise amplifier is designed using the state-of-the-art complementary metal oxide semiconductor 45 nm technology. Berkeley's Predictive Technology Model (PTM) is used to generate a fairly accurate mathematical model and the SPICE data is implemented into the BSIM 4 version of the Advanced Design Systems (ADS) program. The low noise design strategy is mainly based on the analysis of high frequency CMOS operation. This LNA has two stages: the first stage is a RL feedback amplifier …

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A Comparison Method To Evaluate Motion Splicing Techniques, George Thekkanath Raphael Jan 2010

A Comparison Method To Evaluate Motion Splicing Techniques, George Thekkanath Raphael

Electrical Engineering Theses - Archive

The development of methods for the re-use and modification of motion data is an activearea of research. Among these methods, we find automatic techniques to generate a spliced motion by combining different actions recorded in separate sessions. Motion splicing allows capturing motion independently and later combining them to create a new natural looking motion. Even though there have been a lot of research on motion editing techniques, less focus has been given to evaluate these edited motions. In this thesis, we present a novel methodology to quantitatively evaluate the synthesized motion generated by different motion editing techniques. We implemented three …

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Low Complexity H.264 Encoder Using Machine Learning., Thejaswini Purushotham Jan 2010

Low Complexity H.264 Encoder Using Machine Learning., Thejaswini Purushotham

Electrical Engineering Theses - Archive

H.264 is currently one of the most widely accepted video coding standards in the industry. Several software and hardware solutions for the H.264 video encoder exist in the market at present. H.264 is used in such applications as Blu-ray Disc, videos on the internet, digital video broadcast, direct-broadcast satellite television service, cable television services, and real-time videoconferencing. This thesis uses the WEKA (Waikato Environment for Knowledge Analysis) tool to generate the classification rule. WEKA is detailed in Chapter 3. The input attributes to the WEKA have been calculated from the video sequence to be encoded. The procedure has been elaborated …

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Development Of A Preliminary Cost Estimation Method For Water Treatment Plants, Jwala Raj Sharma Jan 2010

Development Of A Preliminary Cost Estimation Method For Water Treatment Plants, Jwala Raj Sharma

Civil Engineering Theses - Archive

Reliable cost estimates for construction, and operation and maintenance (O&M) of water treatment plants are essential for their project planning and design. During the planning phases of the project, preliminary cost estimates are developed for major project components, and for screening of alternatives.Construction and O&M cost curves are widely used for developing preliminary cost estimates. This method is time consuming and there is possibility of human errors. Therefore, for this thesis, construction, and O&M cost equations were developed considering historical cost data for different unit operations and processes involved in a water treatment plant. These equations were developed from historical …

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Solution To Incompressible Navier Stokes Equations By Using Finite Element Method, Wanchai Jiajan Jan 2010

Solution To Incompressible Navier Stokes Equations By Using Finite Element Method, Wanchai Jiajan

Mechanical and Aerospace Engineering Theses - Archive

The finite element method has become a popular method for the solution of the incompressible Navier-Stokes equations. High Reynolds number cases require fine meshes so computational efficiency becomes an important factor in algorithm and code development. In this work, a Galerkin finite element method is proposed to solve the two dimensional incompressible Navier-Stokes equations. This approach typically leads to a sparse and indefinite matrix that is difficult to solve efficiently. The formation of an indefinite matrix is avoided in the present work by introducing an artificial compressibility term in the continuity equation. The concept of this method is to transform …

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Finite Element Analysis Of Stresses In Involute Spur & Helical Gear, Shreyash D. Patel Jan 2010

Finite Element Analysis Of Stresses In Involute Spur & Helical Gear, Shreyash D. Patel

Mechanical and Aerospace Engineering Theses - Archive

Developing an analytical approach and modeling procedure to evaluate stress distribution under velocity and moment would provide a useful tool to improve spur gear design with high efficiency & low cost. The purpose of this work is to analyze and validate the stress distribution in spur & helical gears using contemporary commercial FEM program ANSYS coupled with the Pro/E solid modeler. Gear profiles are created in Pro Engineer using the Relation and Equation modeling procedure so as to make it a general model, dependant on certain key features like number of teeth, diametral pitch, and pressure and helix angle. These …

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Effects Of Curvature On The Stresses Of A Curved Laminated Beams Subjected To Bending, Thien Nguyen Jan 2010

Effects Of Curvature On The Stresses Of A Curved Laminated Beams Subjected To Bending, Thien Nguyen

Mechanical and Aerospace Engineering Theses - Archive

In aircraft structural applications, curved laminated beam structures are often used as part of the internal structure. If the curved composite structure is subjected to bending that tends to flatten or compress the composite structure, interlaminar stresses can be generated in the thickness direction of the composites. These interlaminar stresses are the major factor of delamination failure. Besides these stresses, the in-plane stresses can be also affected by the pre-existence of the beam curvature. This research has studied the variation of both tangential and radial stresses with respect to the changing in curvature, stacking sequence, and fiber orientation in a …

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Failure Assessment In Aerospace Systems Via Integrated Multi-Functional Sensors, Ismail Erkin Gonenli Jan 2010

Failure Assessment In Aerospace Systems Via Integrated Multi-Functional Sensors, Ismail Erkin Gonenli

Electrical Engineering Dissertations - Archive

Integrated sensors fabricated on flexible substrates show lots of promise due to their ability to conform on non-planar surfaces. Potential applications could be smart-skin and wearable electronics which can be used on prosthetic devices or in harsh environments to provide with the sense of feel of the ambient. Design, fabrication and characterization of MEMS piezoresistive pressure sensors and capacitive accelerometers were done on Si and flexible polymer substrates using surface micromachining to be used on aerospace applications. Devices were successfully tested on planar surfaces.For the pressure sensor fabrication, Si3N4 was used as a membrane material due to its linearity and …

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The Self-Heating Effects Of Bipolar Juction Transistors On The Functionality Of A Current Feedback Amplifier, Xuesong Xie Jan 2010

The Self-Heating Effects Of Bipolar Juction Transistors On The Functionality Of A Current Feedback Amplifier, Xuesong Xie

Electrical Engineering Dissertations - Archive

Self-heating effects strongly affect the performance of modern silicon-on-insulator (SOI) bipolar junction transistors. This research work does an extensive analysis of self-heating effects on large-signal behavior, small-signal behavior and transient operation of bipolar junction transistors. The two mechanisms in which device temperature affects large-signal behavior of a BJT transistor are investigated, i.e. the common-emitter (CE) configuration is to be driven by a constant base-emitter voltage and a constant base current. It is shown that the output characteristic of a BJT transistor is less sensitive to self-heating under a fixed base current than a fixed base-emitter voltage. A simple method of …

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High Detectivity Pyroelectric Infrared Detector, Annand Balasubramaniyam Jan 2010

High Detectivity Pyroelectric Infrared Detector, Annand Balasubramaniyam

Electrical Engineering Theses - Archive

The sensors which measure physical quantities by sensing them as thermal quantities and then converting the thermal signals into electrical signals are called thermal sensors. One such type of thermal sensor is a pyroelectric infrared sensor. Thermal sensors are not popular mainly because they are slow devices, and they have low sensitivity when compared to photon detectors. One major advantage of thermal detectors over photon detectors is that they can operate at room temperature. This is one of the main motivations for this research. The aim of the thesis is to design an uncooled, high detectivity pyroelectric infrared detector. The …

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Charge Pump Circuit, Paras Shah Jan 2010

Charge Pump Circuit, Paras Shah

Electrical Engineering Theses - Archive

The sole aim of this work is to show how to generate higher voltages greater than the power supply voltage. This idea is implemented using transistors and capacitors on silicon and is called a charge pump circuit. A charge pump circuit is implemented as a voltage doubler circuit in this work using 0.25um gate length technology. A 6-stage Dickson charge pump circuit was designed to produce a 15 V output from a 5 V supply using two phase non-overlapping clock signals that drive the charge pump. It also describes the advanced architectures with complex circuit design and dynamic techniques for …

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Passive Rf Sensors And Wireless Sensor Interrogation, Srikar Deshmukh Jan 2010

Passive Rf Sensors And Wireless Sensor Interrogation, Srikar Deshmukh

Electrical Engineering Theses - Archive

Recently, a new type of passive sensor called the antenna sensor has been developed. The antenna sensor incorporates a patch antenna as the sensing element as well as the data transmitting element. Physical factors such as strain and ground plane crack cause the patch antenna resonant frequency to change. By measuring the change in patch antenna resonant frequency these physical factors can be quantified.Conventional resonant frequency measurement methods require a wired connection to the antenna sensor. The wireless interrogation technique eliminates this requirement while offering all the advantages that a wireless sensor interface offers over a wired sensor interface. In …

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A High Fill Factor Cmos Image Sensor For Ir Camera Applications, Daniel Mcbride Jan 2010

A High Fill Factor Cmos Image Sensor For Ir Camera Applications, Daniel Mcbride

Electrical Engineering Theses - Archive

In this thesis, a unit cell for high-SNR applications is presented. The proposed circuit is significantly smaller than other circuits that perform dark current subtraction because less circuitry is used inside the unit cell. The proposed circuit uses only two transistors and one resistor inside each unit cell to suppress the dark current. The size of the circuit in the layout is 25 um x 25 µm. With this new unit cell and routing approach, the size of the unit cell was reduced by 300% compared to other circuits which also suppress dark current.

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Implementation Of Security Within Gen2 Protocol, Shesh Kumar Jagannatha Jan 2010

Implementation Of Security Within Gen2 Protocol, Shesh Kumar Jagannatha

Electrical Engineering Theses - Archive

In this thesis, I propose and evaluate several methods to integrate security within the identification process and memory access processes of the ISO 18000-6C (or GEN2) passive UHF radio frequency identification (RFID) protocol. The RFID Tags are promiscuous and they emit their unique identifiers in clear upon interrogation from the Reader. They do not have a mutual authentication process to validate the Readers and Tags, this allows eavesdropping, illicit reading from a malicious Reader and counterfeit Tags. GEN2 Tags are being integrated into driver's licenses and being used for border crossing identities; thus, there is a need to secure both …

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Quantitative Variation Of Blood Pressure Dynamics During Sleep Apnea, Raichel Mary Alex Jan 2010

Quantitative Variation Of Blood Pressure Dynamics During Sleep Apnea, Raichel Mary Alex

Bioengineering Theses - Archive

Sleep Apnea is one of the major sleep disorders characterized by complete cessation or decline in breathing for about 10s or more during sleep, thereby adversely affecting the quality of sleep. Studies show that about 6 % of the US adult population suffers from obstructive sleep apnea, which in turn plays a major role in the development of hypertension, heart failure, stroke and is also responsible for reduced performance in everyday activities due to lack of quality sleep. In this study the physiological response to sleep apnea were determined using beat to beat blood pressure in both healthy subjects and …

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Innovations In ¹H Mr Tissue Oximetry: New Probes And Pulses, Ujjawal Rastogi Jan 2010

Innovations In ¹H Mr Tissue Oximetry: New Probes And Pulses, Ujjawal Rastogi

Bioengineering Theses - Archive

Low oxygenation level (hypoxia) of tissue leads to cellular dysfunction, damage and poor response to therapy. Quantitative measurement of tissue oxygenation is critical not only for the study of tissue physiology, but could also help improve efficacy of therapeutic procedures. Our group has previously developed and implemented a novel approach to quantify oxygen tension in tissue using ¹H MRI, known as “PISTOL” (Proton Imaging of Siloxanes to map Tissue Oxygenation Levels). It exploits a linear relationship between the longitudinal relaxation rate (R1) and oxygen tension (pO₂) of a reporter molecule (probe). Due to close proximity of fat (~ 1 ppm) …

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A Study Of The Physiological Effects Of Sleep Apnea On Cerebral Blood Flow Velocity, Gauri Bhave Jan 2010

A Study Of The Physiological Effects Of Sleep Apnea On Cerebral Blood Flow Velocity, Gauri Bhave

Bioengineering Theses - Archive

It is estimated that sleep apnea is prevalent in the US in about 18 million people. The prevalence rate is approximately 6% in the US. Sleep apnea reduces the quality of life of patients. Sleep apnea is characterized by repetitive pauses in breathing during sleep. Recent studies also show loss of gray matter in people diagnosed with sleep apnea. To study the physiological effects of sleep apnea on cerebral blood flow velocity (CBFV), CBFV was measured in subjects simulating apnea. Sixteen volunteers (29 ± 5 yr and BMI 24.1±4.8, 9M and 7F) were recruited as control subjects. We measured CBFV …

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An Investigation Of Peripheral Blood Volume And Oxygen Saturation Change In Obstructive Sleep Apnea, Swathi Iyer Jan 2010

An Investigation Of Peripheral Blood Volume And Oxygen Saturation Change In Obstructive Sleep Apnea, Swathi Iyer

Bioengineering Theses - Archive

Obstructive sleep apnea (OSA) is a type of sleep disordered breathing in which the airway collapse partially or fully and causes arousal to resume breathing. In a 2009 National sleep foundation poll of 1000 people, 63% of men and 50% of the females showed signs of sleep apnea. It also showed that subjects with sleep apnea have high risk of high blood pressure, stroke and mental disorders such as depression especially in female. Also by another group of researcher it has been shown that the prevalence of OSA is 4% in male and 2% in female. It has been also …

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In Vivo Tracking Of Mesenchymal Stem Cell Recruitment To Tissue Scaffolds, Manwu Sun Jan 2010

In Vivo Tracking Of Mesenchymal Stem Cell Recruitment To Tissue Scaffolds, Manwu Sun

Bioengineering Theses - Archive

The term "Stem cells" has been extensively used to describe precursor undifferentiated cells that have the capacity to self-renew and can also give rise to multiple tissue types. Many studies have been shown improved functional outcome after treated with stem cell therapy. However, almost all of these investigations were analyzed based on histological evaluations which are time-consuming, expensive and fail to provide 3 dimensional and real-time information about stem cell responses. Therefore, there is a need for the development of new method to investigate the migration of stem cells in vivo. Recent evidence supports that fluorescence imaging system offer both …

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Attenuation Based Quantification Of Interstitial Lung Disease Using High Resolution Computed Tomography And Correlation With Pulmonary Function Tests, Snehal S. Watharkar Jan 2010

Attenuation Based Quantification Of Interstitial Lung Disease Using High Resolution Computed Tomography And Correlation With Pulmonary Function Tests, Snehal S. Watharkar

Bioengineering Theses - Archive

Interstitial lung disease (ILD) is a chronic and progressive pulmonary disease of the lung parenchyma resulting in fibrotic scar formation of the pulmonary alveoli. The pathologic changes in the lung result in restrictive impairment of lung function. High resolution computed tomography (HRCT) of the chest has become an essential technique in diagnosing and assessing the extent of ILD. Clinical evaluation by HRCT is usually qualitative, leading to inter-observer variability particularly in detecting early disease. We propose a quantitative attenuation-based analysis to standardize the assessment of regional lung disease. We hypothesize that early ILD is associated with greater regional heterogeneity than …

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A Micromechanics Model Of Thermal Expansion Coefficient In Fiber Reinforced Composites, Nittapon Srisuk Jan 2010

A Micromechanics Model Of Thermal Expansion Coefficient In Fiber Reinforced Composites, Nittapon Srisuk

Mechanical and Aerospace Engineering Theses - Archive

Fiber reinforced composites are widely used for the various applications in the aerospace, automotive, infrastructures and sporting goods industries. The evaluations of its mechanical and thermal properties are needed for accurate estimation of their structural response. In this study, a mathematical closed-form expression of unit cell model was developed to estimate the coefficient of thermal expansion (CTE) along longitudinal and transverse directions of unidirectional lamina. Unlike the previous models, the present model takes into consideration of the fiber configuration and volume fraction of each constituent in the unit cell. In addition, the model is also able to obtain the stresses …

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Dynamic Thermal Management Of Multi Core Processors Using Core Hopping, Avinash Raghu Jan 2010

Dynamic Thermal Management Of Multi Core Processors Using Core Hopping, Avinash Raghu

Mechanical and Aerospace Engineering Theses - Archive

Multi core processors are the order of the day today. The demand for greater levels of performance and the consequent increase in design complexity have rendered the single core processor obsolete and resulted in more cores being put onto a single chip. Processors incorporating more than 4 cores on a chip are dubbed many core processors. This, while improving performance, has lead to increased power densities. Also, the power distribution across the die surface is not uniform. These factors together, result in heat being concentrated at specific points on the die surface, called `hot spots'.The increase in die temperature results …

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Mean Pressure Measurements Of Micro-Vortex Generator At Mach 2.5, Yusi Shih Jan 2010

Mean Pressure Measurements Of Micro-Vortex Generator At Mach 2.5, Yusi Shih

Mechanical and Aerospace Engineering Theses - Archive

Shock wave/boundary layer interactions (SBLIs) are always an important issue for high-speed vehicles. SBLIs reduce the performance of aerodynamic surfaces and engine inlets, amongst a number of adverse effects. Micro-vortex generators (MVGs) are a potential flow control method that has seen intense investigation recently and have even been implemented in actual configurations at low speeds. The present research is focused on the mean pressures at Mach 2.5 around an MVG. Experiments were performed with a baseline flat plate and also with two MVG configurations (70 and 45 trailing edge) mounted ahead of a 5° ramp. In the present study MVGs …

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Axial Wave Propagation In Truncated Cones, Bhumil A. Diwanji Jan 2010

Axial Wave Propagation In Truncated Cones, Bhumil A. Diwanji

Mechanical and Aerospace Engineering Theses - Archive

While dealing with problems of impact analysis, where the force is dependent on the time, one can use the transient analysis to compute the response. Transient wave propagation has drawn interest from a long time mainly because of the way structural members behave when subjected to high rates of loading. Solutions to these problems find applications in the design of various mechanical equipments, or any situation where rigid objects are impacting on structural members.The first part of this study deals with the axial wave propagation in cones of different apex angles using transient analysis in ANSYS. The results from the …

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Fiber-Optic Pressure Sensor For Time-Of-Flight Measurements In A Shock Wave, Karthikeyan Jagadevan Jan 2010

Fiber-Optic Pressure Sensor For Time-Of-Flight Measurements In A Shock Wave, Karthikeyan Jagadevan

Mechanical and Aerospace Engineering Theses - Archive

Fiber-optic sensors are widely employed to detect pressures and temperatures precisely. In particular, MEMS-based Ber-optic sensors are immune to electromagnetic interference but may have limitations at high temperatures as encountered in combustors. To ensure high-temperature survivability, such sensors may be bondedanodically. This project explains the development of a Ber-optic pressure sensor utilizing intensity based principle whereby a fused silica optical window was glued to the tungsten carbide enclosure. The development was estimated to determine high pressures of up to at least 3.5 MPa (507 psi). The sensor is designed to capture the pressure pulse and the time-of-flight (TOF) of a …

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Peak Stress Of Composite Multiple-Hole Laminates With And Without Patch, Sakthivel Selvaraj Jan 2010

Peak Stress Of Composite Multiple-Hole Laminates With And Without Patch, Sakthivel Selvaraj

Mechanical and Aerospace Engineering Theses - Archive

In repairing of composite structures, the damage in the composite laminate is usually removed in the form of circular cutouts which results in holes in the laminate. Then a patch laminate is adhesively bonded to the damaged composite laminate. The presence of holes in any structures creates a high stress concentration at the edge of the hole which indeed reduces the life of the structure. The primary objective of this study is to investigate the high stress of the damaged laminate with different hole patterns and the effect of having single and double patches with various configurations on these hole …

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