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Articles 1 - 30 of 92
Full-Text Articles in Mechanical Engineering
Measurement Of High Strain Regions In Particulate Composites Using Digital Image Correlation, Tsuchin Chu, Ajay Mahajan
Measurement Of High Strain Regions In Particulate Composites Using Digital Image Correlation, Tsuchin Chu, Ajay Mahajan
Dr. Ajay Mahajan
This paper presents a methodology for the measurement of high strain regions in particulate composites used as rocket fuel. It is shown that there is statistical distribution of high strain regions through out a strained material. A theory is developed to determine the threshold that determines the identification of the high strain regions. It is shown that by using this approach it is possible to identify high strain regions that eventually lead to failure. These high strain regions are determined experimentally by using a high digital image correlation approach. This work may be used to identify very early on regions …
A Novel Method To Create Intelligent Sensors With Learning Capabilities To Improve Modern Production Systems, Ajay Mahajan
A Novel Method To Create Intelligent Sensors With Learning Capabilities To Improve Modern Production Systems, Ajay Mahajan
Dr. Ajay Mahajan
A formal theory for the development of a generic model of an autonomous sensor is proposed and implemented. An autonomous sensor is defined as an intelligent sensor that has machine learning capabilities. It not only interprets the acquired data in accordance with an embedded expert system knowledge base, but is also capable of using this data to modify and enhance this knowledge base. Hence, the system is capable of learning and thereby improving its performance over time. The main objective of the model is to combine the capabilities of the physical sensor and an expert operator monitoring the sensor in …
Multisensor Fusion Using Fuzzy Logic For An Integrated Smart Health Monitoring System, Amit Mojanty, Chris Leach, Ajay Mahajan
Multisensor Fusion Using Fuzzy Logic For An Integrated Smart Health Monitoring System, Amit Mojanty, Chris Leach, Ajay Mahajan
Dr. Ajay Mahajan
This paper presents a generic model for an integrated smart health monitoring system for infrastructures using multisensor fusion and condition assessment sheets. Though various techniques for health monitoring have been discussed extensively in the literature, little attention has been given to obtain high quality data from the measurement and sensing system by using an intrinsic knowledge base. The method proposed in this paper uses measurement data from different types of sensors with different resolutions and fuses it together based on the confidence in them derived from information not typically used in traditional data fusion methods. Examples of such information are …
Optimum Grid By Direct Optimization Methods, Ajay Mahajan, Richard Hindman
Optimum Grid By Direct Optimization Methods, Ajay Mahajan, Richard Hindman
Dr. Ajay Mahajan
A solution-adaptive grid procedure based on optimization is developed and applied to the Linearized Viscous Burger's governing equation. The scheme redistributes the grid points as the solution adapts through each successive iteration step to minimize the truncation error terms in the modified equation and satisfy the governing equation. Fist order Roe scheme is used to discretize the governing equation. If the truncation error terms become negligible and the governing equation is satisfied by the scheme then the numerical solution approaches the exact solution.
Intelligent System Identification Using Neural Networks And Genetic Algorithms Of An Ultrasonic Positioning System, Nishant Unnikrishnan, Ajay Mahajan
Intelligent System Identification Using Neural Networks And Genetic Algorithms Of An Ultrasonic Positioning System, Nishant Unnikrishnan, Ajay Mahajan
Dr. Ajay Mahajan
This paper presents an intelligent system identification methodology for the identification of a realistic model of an ultrasonic position estimation system that uses the difference in the time of arrivals of waves from a transmitter to various receivers. Even though a linearized formulation for the 3D system exists and is currently being used to estimate the position of the transmitter, its accuracy can still be improved further. A neural network approach is developed to train the system based on training sets obtained from the actual system, and it is proposed to use the final trained system to estimate the 3D …
Euler Analysis Of A Two Dimensional Scramjet Inlet, Ajay Mahajan
Euler Analysis Of A Two Dimensional Scramjet Inlet, Ajay Mahajan
Dr. Ajay Mahajan
There are several advantages in using a zonal method. First, and most important, it allows the generation of structured grids around two or three dimensional complex geometries. Second, zonal methods allow different types of grid topologies to be used in order to improve mesh efficiency. A structured mesh is used in all the zones with matching dimensions on the interface boundaries. The Runge-Kutta Explicit scheme is used to march in time from the 1st zone to the last zone sequentially. The zones are fully coupled, whereby information is allowed to propagate between the zones. Far field boundary conditions are applied …
Workforce Training Through Industry-University Partnerships For Improved Technology Management, David Mcdonald, Ajay Mahajan
Workforce Training Through Industry-University Partnerships For Improved Technology Management, David Mcdonald, Ajay Mahajan
Dr. Ajay Mahajan
No abstract provided.
Engineering Analysis With Maple/Matematica. Al Beltzer, Mohamad Qatu, Ajay Mahajan
Engineering Analysis With Maple/Matematica. Al Beltzer, Mohamad Qatu, Ajay Mahajan
Dr. Ajay Mahajan
No abstract provided.
Application Of Wavelet Transforms In The Analysis Of High-Frequency Squeal In A Disc Brake System, Manish Paliwal, Ajay Mahajan, Jarlen Don, Peter Filip
Application Of Wavelet Transforms In The Analysis Of High-Frequency Squeal In A Disc Brake System, Manish Paliwal, Ajay Mahajan, Jarlen Don, Peter Filip
Dr. Ajay Mahajan
This paper presents the application of wavelet transforms in the analysis of high frequency squeal in an automotive disc brake system. It is shown that valuable information can be obtained from a wavelet analysis over and above that obtained from traditional Fourier Transform approaches. The primary reason for this is that the squeal in brakes is a time varying phenomenon that may have sharp transitions in time. This paper also attempts to correlate field data analysis with the results from an analytical model that has been developed to investigate the role of the friction layer in the generation of squeal.
An Intelligent Systems Approach For An Ultrasonic Based Neuro-Navigation System, Jennifer Akers, Sanjeevi Chitikeshi, Ajay Mahajan, Tsuchin Chu, Etienne Witte, Sumeer Lal
An Intelligent Systems Approach For An Ultrasonic Based Neuro-Navigation System, Jennifer Akers, Sanjeevi Chitikeshi, Ajay Mahajan, Tsuchin Chu, Etienne Witte, Sumeer Lal
Dr. Ajay Mahajan
This paper shows the feasibility of using an intelligent systems approach to increase the accuracy of a 3D ultrasonic position estimation system for real-time image guided neurosurgery. Current image guided systems use camera based technology that is space-intensive, have an accuracy of about 1.0–2.0 mm, and are prone to occasional failures. The 3D system presented in this paper eliminates the space intensive camera, has an accuracy of around 1.0 mm in the operating range of about 200–400 mm, makes the system independent of line-of-sight occlusion problems, and is expected to pave the way for accurate fusion models of MRI and …
Short Crack Growth Model In A Particulate Composite Using Nonlinear Elastic Fracture Mechanics, Ying Zhang, Tsuchin Chu, Ajay Mahajan
Short Crack Growth Model In A Particulate Composite Using Nonlinear Elastic Fracture Mechanics, Ying Zhang, Tsuchin Chu, Ajay Mahajan
Dr. Ajay Mahajan
The fracture mechanics model for a long crack does not work very well with short-crack propagation when the initial crack length is less than 5.1 mm (0.2 inch). In order to investigate the short crack effect, a series of tests of particulate composite specimens with long and short cracks were performed and the results recorded on a video tape. This test data was analyzed to determine the fracture parameters. Two initial crack lengths, 2.5 mm (0.1 inches) and 7.6 mm (0.3 inches) were used in the crack propagation tests. Based on the principle of linear elastic fracture mechanics (LEFM), the …
An Intelligent Foot Monitoring System For Diabetic Patients To Prevent Foot Ulcerations, Vyshali Chitikeshi, Ajay Mahajan, Sanjeevi Chitikeshi, Ravinder Gupta, Marco Schoen
An Intelligent Foot Monitoring System For Diabetic Patients To Prevent Foot Ulcerations, Vyshali Chitikeshi, Ajay Mahajan, Sanjeevi Chitikeshi, Ravinder Gupta, Marco Schoen
Dr. Ajay Mahajan
Elevated plantar pressure plays a major role in foot problems in diabetic patients. High pressures interrupt arterial blood flow, which is further compounded by the fact that diabetic patients lose sensory feedback from their feet, hence are not able to change their stance leading to unnatural pressure points. This can lead to dermal ulcerations, necrosis, and ultimately to partial or total amputation of the foot. This paper presents a preliminary design of an intelligent shoe-insert that automatically monitors critical foot parameters in diabetic patients. The objective is to collect information on plantar pressure, temperature and moisture and come up with …
Active Foot Pressure Control For Diabetic Neuropathy During Walking, Vidya Nandikolla, Marco Schoen, Ajay Mahajan
Active Foot Pressure Control For Diabetic Neuropathy During Walking, Vidya Nandikolla, Marco Schoen, Ajay Mahajan
Dr. Ajay Mahajan
Diabetic Mellitus is a disease caused either due to insufficient insulin produced by the pancreas or the body cells are unable to use the existing insulin. One of the main complications associated with diabetics is neuropathy, which is caused due to complete or partial loss of sensation in the feet and legs that lead to problems like inadequate delivery of nutrients and oxygen to the foot, which will cause healing impairment. In diabetic neuropathic subject, the hardness of foot sole soft tissue gives rise to plantar ulcer development. In this work, a biomechanical model is used to study the plantar …
Active Foot Pressure Control For Diabetic Patients, Vidya Nandikolla, Marco Schoen, Ajay Mahajan
Active Foot Pressure Control For Diabetic Patients, Vidya Nandikolla, Marco Schoen, Ajay Mahajan
Dr. Ajay Mahajan
Foot Ulcer in diabetic patients is a serious medical problem. A major contributor for the development of diabetic foot ulcers is a high, localized plantar foot pressure. It is believed that in diabetes the nerves in the extreme parts of the human body are damaged and cause deregulated blood flow, which may cause an insufficient blood supply. This can lead to a loss of feeling, change in shape of the feet, necrosis and ulcerations, and ultimately to partial or total amputation of the body part. The loss of feeling in the feet results in a loss of feedback to control …
Pso: A Novel Technique To Optimize A Coal Preparation Plant, Vishal Gupta, Hussain Unjawala, Ajay Mahajan, Manoj Mohanty
Pso: A Novel Technique To Optimize A Coal Preparation Plant, Vishal Gupta, Hussain Unjawala, Ajay Mahajan, Manoj Mohanty
Dr. Ajay Mahajan
A coal preparation plant typically has multiple cleaning circuits based on size of coal particles. Each circuit is operated to produce the same product quality so that the blend of clean coal meets the targeted product quality constraints. Though, this approach of producing the clean coal satisfies the product quality constraints as given by the customer, it may suffer from the loss of overall clean coal yield by 1–2%. Numerous studies conducted in the past illustrate that the optimal yield can be obtained by operating each circuit to produce the same incremental product quality. However, this approach is good enough …
Optimization Of Threshold Values For Estimators Based On Single-Bit Quantized Sensors Using Genetic Algorithms, Nishant Unnikrishnan, Ajay Mahajan, Antonios Mengoulis, R. Viswanathan
Optimization Of Threshold Values For Estimators Based On Single-Bit Quantized Sensors Using Genetic Algorithms, Nishant Unnikrishnan, Ajay Mahajan, Antonios Mengoulis, R. Viswanathan
Dr. Ajay Mahajan
The paper considers the problem of signal parameter estimation using a collection of distributed sensors called a sensor pack. Each sensor quantizes its data to one-bit information and sends it to a fusion processor for the estimation of the parameter. Estimation of a constant signal in additive noise is considered. Estimators are formulated based on one-bit sensor data and their mean squared error (MSE) performances are evaluated through simulation studies. It is shown that selecting certain threshold values for quantizing the sensor outputs can lower the MSE. Genetic algorithms are used to find the optimal threshold values for the sensors. …
Improved Accuracy Of An Ultrasonic Based Neuro-Navigation System Using Neural Networks, Jennifer Akers, Sanjeevi Chitikeshi, Ajay Mahajan, Sumeer Lal
Improved Accuracy Of An Ultrasonic Based Neuro-Navigation System Using Neural Networks, Jennifer Akers, Sanjeevi Chitikeshi, Ajay Mahajan, Sumeer Lal
Dr. Ajay Mahajan
This paper presents the design and development of an ultrasonic based neuronavigation system to be used for real time surgery. The system formulation, hardware and a neural network model is presented that improves the accuracy of the system considerably. 1D, 2D and 3D results from the neural network model are presented along with designs for the physical and electronic hardware. The 3D system presented in this paper eliminates the space intensive camera, has an accuracy better than 1.0 mm in the operating range of about 20–40 cm, makes the system independent of line-of-sight occlusion problems, and is expected to pave …
Genetic Algorithms — A Novel Technique To Optimize Coal Preparation Plants, Vishal Gupta, Manoj Mohanty, Ajay Mahajan, S. Biswal
Genetic Algorithms — A Novel Technique To Optimize Coal Preparation Plants, Vishal Gupta, Manoj Mohanty, Ajay Mahajan, S. Biswal
Dr. Ajay Mahajan
A coal preparation plant typically operates with multiple cleaning circuits based on the particle size distribution of run-of-mine coal. Clean coal product from a plant commonly has to satisfy multiple product quality constraints, including product ash, product sulfur, heating value, moisture content, etc. Numerous studies in the past illustrate that the optimal yield of the plant can be obtained by operating each circuit to produce the same incremental product quality. This equal incremental product quality approach optimizes the plant yield considering only one product quality at a time. Thus, when required to simultaneously satisfy multiple product quality constraints, the process …
Multisensor Integration And Fusion Model That Uses A Fuzzy Inference System, Ajay Mahajan, Kaihong Wang, P. Ray
Multisensor Integration And Fusion Model That Uses A Fuzzy Inference System, Ajay Mahajan, Kaihong Wang, P. Ray
Dr. Ajay Mahajan
An intelligent multisensor integration and fusion model that uses fuzzy logic is developed. Measurement data from different types of sensors with different resolutions are integrated and fused based on the confidence in them derived from information not usually used in data fusion, such as operating temperature, frequency range, fatigue cycles, etc. These are fed as additional inputs to a fuzzy inference system (FIS) that has predefined membership functions for each of these variables. The output of the FIS are weights that are assigned to the different sensor measurement data that reflect the confidence in the sensor's behavior and performance. A …
Intelligent Sensors: Strategies For An Integrated Systems Approach, Sanjeevi Chitikeshi, Ajay Mahajan, Pavan Bandhil, Lucas Utterback, Fernando Figueroa
Intelligent Sensors: Strategies For An Integrated Systems Approach, Sanjeevi Chitikeshi, Ajay Mahajan, Pavan Bandhil, Lucas Utterback, Fernando Figueroa
Dr. Ajay Mahajan
This paper proposes the development of intelligent sensors as an integrated systems approach, i.e. one treats the sensors as a complete system with its own sensing hardware (the traditional sensor), A/D converters, processing and storage capabilities, software drivers, self-assessment algorithms, communication protocols and evolutionary methodologies that allow them to get better with time. Under a project being undertaken at the Stennis Space Center, an integrated framework is being developed for the intelligent monitoring of smart elements. These smart elements can be sensors, actuators or other devices. The immediate application is the monitoring of the rocket test stands, but the technology …
Adaptive Multi Airbag Shoe Insert For Diabetic Foot Care, Vidya Nandikolla, Jenna Matthews, Marco Schoen, Suhas Pharkute, Uwe Reischl, Ajay Mahajan
Adaptive Multi Airbag Shoe Insert For Diabetic Foot Care, Vidya Nandikolla, Jenna Matthews, Marco Schoen, Suhas Pharkute, Uwe Reischl, Ajay Mahajan
Dr. Ajay Mahajan
Diabetic mellitus patients have foot problems such as loss of sensation, insufficient blood flow to lower extremities and alterations in shape of their pressure patterns causing concentrated high pressure regions. These peaks are due to the disfunctional feed back system from their mechanoreceptors and may lead to complex problems such as amputation if not identified and treated in timely manner. Our main objective is to protect the foot by sensing the abnormal peaks and redistribute the pressure from excessive pressure regions. Therefore, we are developing a design layout for an adaptable shoe insert useful for diabetic foot care. In this …
A Robust Navigation System For Autonomous Vehicles Using Ultrasonics, F. Figueroa, Ajay Mahajan
A Robust Navigation System For Autonomous Vehicles Using Ultrasonics, F. Figueroa, Ajay Mahajan
Dr. Ajay Mahajan
A navigation system has been developed for the guidance and control of autonomously guided vehicles using a novel ultrasonic 3D location system in conjunction with traditional ultrasonic rangefinders. This system is most suitable for navigation in structured environments, e.g., factories, hospitals, offices, nuclear power plans and other hazardous areas. The strengths of the system are accuracy (2.54mm), ease of use, self installation/calibration, and fast position update rates (>100Hz). A method for automatic modifications of maps has been implemented. An object-oriented approach has been used to develop a system that is robust and flexible.
An Innovative Integrated Learning Laboratory Environment, Ajay Mahajan, David Mcdonald, Maurice Walworth
An Innovative Integrated Learning Laboratory Environment, Ajay Mahajan, David Mcdonald, Maurice Walworth
Dr. Ajay Mahajan
The current paradigm in engineering course instruction builds on a lecture prerequisite structure but ignores the need for a laboratory prerequisite structure. Educational quality is therefore diminished as instructors optimize specific laboratories but fail to optimize the overall program laboratory experience. This paper presents a learning environment that forces students to use not only concepts and skills acquired from the lecture, but also actual data and models acquired from lower division laboratories, in upper division laboratories. The integration occurs because students must utilize their previous laboratory work as a reference and/or building blocks as they study the different facets of …
Development Of Bamboo‐Derived Sorbents For Mercury Removal In Gas Phase, Naved Siddiqui, Jarlen Don, Kanchan Mondal, Ajay Mahajan
Development Of Bamboo‐Derived Sorbents For Mercury Removal In Gas Phase, Naved Siddiqui, Jarlen Don, Kanchan Mondal, Ajay Mahajan
Dr. Ajay Mahajan
Activated carbon sorbents were synthesized from bamboo precursors by carbonization in an inert atmosphere followed by physiochemical activation with carbon dioxide and finally acidulation in hydrochloric acid. Bamboo strips with and without the epidermal tissue (bark) were used. The morphology and specific surface area changes due to the treatment were analysed. The adsorption characteristics of these sorbents after each stage of treatment were also analysed and the data were correlated to the changes in the physical characteristics of the sorbents. Kinetic studies were conducted on these samples. The adsorption equilibrium and kinetics of elemental mercury adsorption on these carbons were …
Method For Detecting Defects In A Plastic Fuel Bank By Radiography, Ajay Mahajan, John Balkcom, Stephane Galliot
Method For Detecting Defects In A Plastic Fuel Bank By Radiography, Ajay Mahajan, John Balkcom, Stephane Galliot
Dr. Ajay Mahajan
Method for detecting defects in a plastic vehicle tank equipped with internal accessories located inside the tank. The method comprises at least the following steps: a) providing the tank equipped with said internal accessories; b) making a digitized X-ray image of said tank; c) providing a reference image of said tank; d) comparing the digitized X-ray image and the reference image by means of a computer vision software; e) deciding on the presence of defects when differences exist between the digitized X-ray image and the reference image.
A Novel Fiber Optics Based Method To Measure Very Low Strains In Large Scale Infrastructures, Bradley Regez, Mohammad Sayeh, Ajay Mahajan, Fernando Figueroa
A Novel Fiber Optics Based Method To Measure Very Low Strains In Large Scale Infrastructures, Bradley Regez, Mohammad Sayeh, Ajay Mahajan, Fernando Figueroa
Dr. Ajay Mahajan
An optic fiber strain measurement sensing mechanism has been developed that can measure extremely low strains, i.e. in the order of 0–25 microstrains, with a resolution close to 0.1 microstrain. It is an alternate to traditional foil gauges as well as the more recent Fabry–Perot sensors for some applications. It is particularly suited to measure very low strains in large scale infrastructures where portions of the infrastructure can be used to mount extended lengths of the fiber optic, thereby providing high resolution. Examples of such applications are the measurement of small strains or vibrations in large structures such as rocket …
Adaptive Intelligent Control Of Ionic Polymer–Metal Composites, Brijesh Lavu, Marco Schoen, Ajay Mahajan
Adaptive Intelligent Control Of Ionic Polymer–Metal Composites, Brijesh Lavu, Marco Schoen, Ajay Mahajan
Dr. Ajay Mahajan
Electroactive polymers undergo physical deformation in response to external voltage stimuli. These electrically activated polymers possess extraordinary features making them capable of use as lightweight sensors and actuators in manifold applications. The characteristics of applied voltage and environmental conditions, especially the moisture content surrounding the polymer, have a combined influence on the dynamical behavior of these polymers. In order to characterize these polymers under varying environmental conditions, this paper discusses the experimental procedure and modeling techniques used to derive a representative model. Validation of the model derived is provided by comparison tests of the simulated model results and those for …
A Robust Method To Determine The Coordinates Of A Wave Source For 3-D Position Sensing, Fernando Figueroa, Ajay Mahajan
A Robust Method To Determine The Coordinates Of A Wave Source For 3-D Position Sensing, Fernando Figueroa, Ajay Mahajan
Dr. Ajay Mahajan
This work addresses a method for location of a wave source by observing the wave as it reaches various observation points (receivers), or conversely, this is also a method for location of a receiver at an observation point, by probing with waves generated at various sources. The terms observing and probing imply measurement of time-of-flight (TOF) between a source (transmitter) and a receiver. Practical implications of this work include development and improvement of systems that triangulate the position of a point of interest based on TOF measurements to observation points. Typical applications to benefit from this work include 3-D digitization …
Intelligent System Modelling Of A Three-Dimensional Ultrasonic Positioning System Using Neural Networks And Genetic Algorithms, Nishant Unnikrishnan, Ajay Mahajan, Tsuchin Chu
Intelligent System Modelling Of A Three-Dimensional Ultrasonic Positioning System Using Neural Networks And Genetic Algorithms, Nishant Unnikrishnan, Ajay Mahajan, Tsuchin Chu
Dr. Ajay Mahajan
This paper presents a neural network model for a three-dimensional ultrasonic position estimation system that uses the difference in the time of arrivals of waves from a transmitter to various receivers. Even though a linearized analytical model for the three-dimensional system exists and is currently being used to estimate the position of the transmitter, its accuracy is highly dependent on complex and time consuming signal conditioning. A neural network approach is developed to train the system based on unconditioned training sets obtained directly from the receivers. It is proposed to use the final trained system to estimate the three-dimensional position …
Association Of Genetic Polymorphisms With Immunohistochemical Expression Of Thyroid Transcription Factor 1 (Ttf1) In Asian Nsclc Adenocarcinoma Patients, Wan-Teck Lim, Onkar Singh, Edwin Sandaranaj, Ajay Mahajan, Eng Tan
Association Of Genetic Polymorphisms With Immunohistochemical Expression Of Thyroid Transcription Factor 1 (Ttf1) In Asian Nsclc Adenocarcinoma Patients, Wan-Teck Lim, Onkar Singh, Edwin Sandaranaj, Ajay Mahajan, Eng Tan
Dr. Ajay Mahajan
No abstract provided.