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Articles 2401 - 2430 of 2820

Full-Text Articles in Engineering

Development Of Process Techniques For Bistable Microbeam Fabrication, Varsha Francis Jan 2005

Development Of Process Techniques For Bistable Microbeam Fabrication, Varsha Francis

LSU Master's Theses

A design which uses bistable beams to modulate light is suggested in this thesis and appropriate processing techniques are presented. A beam when placed under compression above the Euler limit has two stable states. The compression in an electroplated beam can be controlled by the plating current density of nickel during electrodeposition. This beam is attached to an electromechanical comb. Voltages applied to the combs cause the beam to snap from one stable state to another. Structures were designed with dimensions that gave feasible voltages, snap distances, compressions required to snap. A two mask process was used for the fabrication …

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Electrodeposition Of Magnetic Nanowires And Nanotubes, Despina Mehedintu Davis Jan 2005

Electrodeposition Of Magnetic Nanowires And Nanotubes, Despina Mehedintu Davis

LSU Master's Theses

The current perpendicular to the plane giant magneto-resistance (CPP)-(GMR) effect makes multilayered nanowires of huge interest as magnetic sensor materials. GMR showing multilayer nanostructures are composed of alternating ferromagnetic and nonmagnetic nanometric layers. The giant magnetoresistance (GMR) property is described as a change in electrical resistance when an external magnetic field is introduced. Electrodeposition is the most efficient method for fabricating magnetic nanowires. In addition to the cost-effectiveness, electrodeposition is one of the few methods that can overcome the geometrical restrictions of inserting metals into very deep nanometric recesses, making it the favored method for nanowire and nanotube fabrication. In …

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Analysis And Testing Of Waste Tire Fiber Modified Concrete, Gregory Marvin Garrick Jan 2005

Analysis And Testing Of Waste Tire Fiber Modified Concrete, Gregory Marvin Garrick

LSU Master's Theses

There are very serious problems with the disposal of waste tires in the United States. Experiments were conducted to determine how the properties of concrete were affected by the inclusion of waste tires. Waste tires were used in the form of chips and fibers. The fibers were further divided into batches with different lengths to determine the effect of length has on the properties of concrete. There was a noticeable decline in the compressive strength of the concrete; however there was an increase in the toughness of the concrete. It was concluded that waste tire fibers were more suitable as …

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New Contention Resolution Techniques For Optical Burst Switching, Kishore Reddy Koduru Jan 2005

New Contention Resolution Techniques For Optical Burst Switching, Kishore Reddy Koduru

LSU Master's Theses

Optical burst switching (OBS) is a technology positioned between wavelength routing and optical packet switching that does not require optical buffering or packet-level parsing, and it is more efficient than circuit switching when the sustained traffic volume does not consume a full wavelength. However, several critical issues still need to be solved such as contention resolution without optical buffering which is a key determinant of packet-loss with a significant impact on network performance. Deflection routing is an approach for resolving contention by routing a contending packet to an output port other than the intended output port. In OBS networks, when …

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Experimental Sloshing Studies In Sway And Heave Base Excited Square Tanks, Wei Peng Jan 2005

Experimental Sloshing Studies In Sway And Heave Base Excited Square Tanks, Wei Peng

LSU Master's Theses

In this thesis, free-surface water waves are experimentally investigated with a focus on sloshing in tanks. The sloshing problem is selected for its relatively simple geometry, yet it captures the features of nonlinearities including wave breaking. Free-surface motions are monitored in a square tank with base dimensions of 1 x 1 m2. Sloshing motions have been studied both off- and at resonance in shallow to deep water to investigate nonlinear free surface effects. The tank has been prescribed to move in sway and / or heave excitation. Interesting hysteresis behavior at the surface is captured at and near resonance. Faraday …

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Traffic Engineering And Path Protection In Mpls Virtual Private Networks, Pooja S. Aniker Jan 2005

Traffic Engineering And Path Protection In Mpls Virtual Private Networks, Pooja S. Aniker

LSU Master's Theses

Traffic Engineering (TE) attempts to establish paths for the flow of data in a network so as to optimize the resource utilization and maximize the network performance. One of the main goals of Traffic Engineering is to bring about efficient and reliable network operations. Constraint based routing is the key to Multiprotocol label switching TE. Constraint based routing helps to manage traffic paths within a MPLS network and allows for traffic to flow along certain desired paths. MPLS also supports explicit routing thus providing TE capabilities. MPLS TE enables resiliency and reliability to be built into networks, thus increasing the …

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Water Quality Modeling For Unconventional Bod, Trieu Van Le Jan 2005

Water Quality Modeling For Unconventional Bod, Trieu Van Le

LSU Master's Theses

Predictions of the dissolved oxygen (DO) concentration in a stream are sensitive to the choice of Biochemical Oxygen Demand (BOD) reaction model which frequently is assumed to be first order, although published BOD data sets from analyses of samples from rivers show that many are described best by second order or three-halves order BOD reaction. Two DO models for a stream are developed, one with a second order and the other with a three-halves order BOD reaction. The DO equations are solved using Laplace transform method which simplifies the mathematical solution of the model equations by avoiding difficult to evaluate …

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Advanced Grid Stiffened Composite Structures, Dinesh Maricherla Jan 2005

Advanced Grid Stiffened Composite Structures, Dinesh Maricherla

LSU Master's Theses

In this study Advanced Grid Stiffened (AGS) composite structures are developed and analyzed for their mechanical properties. It is widely known that these structures possess light weight, high strength, and inherent impact resistance. Because of the advantages mentioned above, the AGS composite structures find many applications in aerospace, ship building and construction industries. The purpose of this study is to manufacture AGS composite structures and analyze AGS composite structures as reinforcement members. A FEA model is also developed and validated with the test results. Parametric analysis is also conducted to investigate the effects of different design parameters on these structures. …

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Fracture Toughness Characterization Of Syntactic Foams, Vijay Gorugantu Jan 2005

Fracture Toughness Characterization Of Syntactic Foams, Vijay Gorugantu

LSU Master's Theses

Hollow particle filled polymeric materials called syntactic foams are used as core materials in sandwich composite structures. Syntactic foams find applications in aeronautical and space structures and therefore demand careful study and testing before they can be put to service. In the first part of this thesis work, syntactic foams are fabricated by varying the volume fraction of microballoons and also their density. Four different densities of microballoons are used ranging from 0.22 g/cc to 0.46 g/cc. The volume fraction of the microballoons is varied from 30% to 65%. A set of 3-point bending tests are conducted on these foam …

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Evaluation Of The Spatial Removal Of Nitrogen In The Marshland Upwelling System, Andrea Reneé Turriciano Jan 2005

Evaluation Of The Spatial Removal Of Nitrogen In The Marshland Upwelling System, Andrea Reneé Turriciano

LSU Master's Theses

The Marshland Upwelling System (MUS) is an alternative onsite wastewater treatment technology designed to utilize the natural ecology of saltwater marshes to remove human-borne contaminants. Over the past twelve years, MUSs have been installed in Port Fourchon, Louisiana, Moss Point, Mississippi, and Bayou Segnette, Louisiana. The purpose of this study was to investigate the nitrogen reduction capabilities of the Bayou Segnette system. The objectives of this research were to: 1) determine the first-order removal constants necessary for the development of nitrogen transport equations, 2) explore the spatial dependencies of nitrogen concentrations within the Bayou Segnette system, and 3) determine the …

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Experimental Investigation Of Dynamic Interfacial Interactions At Reservoir Conditions, Wei Xu Jan 2005

Experimental Investigation Of Dynamic Interfacial Interactions At Reservoir Conditions, Wei Xu

LSU Master's Theses

Much of the research on wettability in the existing literature has been done using stocktank oils and at ambient conditions. The main objective of this study is therefore to examine the validity of ambient measurements in inferring in-situ reservoir wettability. For this purpose, Drop-Shape-Analysis for interfacial tension and Dual-Drop-Dual-Crystal (DDDC) contact angle measurements have been carried out using dolomite rock, Yates reservoir stocktank and live crude oils and Yates synthetic brine at Yates reservoir conditions of 82oF and 700 psi. Two types of surfactants (nonionic and anionic) in varying concentrations have been used to study the effect of surfactants on …

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Image Processing Techniques To Identify Predatory Birds In Aquacultural Settings, Uma Devi Nadimpalli Jan 2005

Image Processing Techniques To Identify Predatory Birds In Aquacultural Settings, Uma Devi Nadimpalli

LSU Master's Theses

Bird predation is a major problem in aquaculture. A novel method for dispersing birds is the use of a vehicle that can sense and chase birds. Image recognition software can improve their efficiency in chasing birds. Three recognition techniques were tested to identify birds 1) image morphology 2) artificial neural networks, and 3) template matching have been tested. A study was conducted on three species of birds 1) pelicans, 2) egrets, and 3) cormorants. Images were divided into 3 types 1) Type 1, 2) Type 2, and 3) Type 3 depending upon difficulty to separate from the others in the …

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Target Tracking In Wireless Sensor Networks, Tarun Anand Malik Jan 2005

Target Tracking In Wireless Sensor Networks, Tarun Anand Malik

LSU Master's Theses

The problem being tackled here relates to the problem of target tracking in wireless sensor networks. It is a specific problem in localization. Localization primarily refers to the detection of spatial coordinates of a node or an object. Target tracking deals with finding spatial coordinates of a moving object and being able to track its movements. In the tracking scheme illustrated, sensors are deployed in a triangular fashion in a hexagonal mesh such that the hexagon is divided into a number of equilateral triangles. The technique used for detection is the trilateration technique in which intersection of three circles is …

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A Tablet Pc Application For Construction Site Safety Inspection And Fatality Prevention, Prabhu Sunkara Jan 2005

A Tablet Pc Application For Construction Site Safety Inspection And Fatality Prevention, Prabhu Sunkara

LSU Master's Theses

Construction industry accounts for the largest number of occupational injuries and fatalities every year. Occupational Safety and Health Administration (OSHA) is an organization responsible for regulating and enforcing standards for various occupations to ensure safe working conditions including construction industry. As an OSHA requirement, every construction employer should employ a safety program that involves both training of the employees and frequent site inspections. OSHA has provided an online ‘construction eTool’ as a training tool which also aids in the development of safety inspection procedures. Traditionally, safety inspections are paper based and usually designed to address a specific work area or …

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Development Of Software To Process Aerial Images For Agricultural Purposes, Sirisha Polsapalli Jan 2005

Development Of Software To Process Aerial Images For Agricultural Purposes, Sirisha Polsapalli

LSU Master's Theses

Remote sensing has been used in precision agriculture for monitoring crop health, weed management, detecting nutrient stress, and yield forecasting. One method of implementing remote sensing is through aerial imagery. Aerial imagery is being used in precision agriculture for a variety causes such as to detect crop stress, fertilizer skips and overlaps, nitrogen excesses and deficiencies and detect irregular or reduced crop stand. These crop features are noted by extracting spectral information from the images. The spectral data is obtained from the images by using software programs. The software programs process the images one at a time or assemble them …

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Two Dimensional Sediment Transport Model Using Parallel Computers, Vikas Singh Jan 2005

Two Dimensional Sediment Transport Model Using Parallel Computers, Vikas Singh

LSU Master's Theses

Management and development of water bodies is vital for meeting domestic, agricultural, energy and industrial needs. To that end, dams, artificial channels, lakes and other water structures have been constructed. Management and development of these structures encounter problems of land erosion, reservoir silting, and degradation and aggradation of channel beds, which need to be addressed. Fundamental to these problems are sediment transport, erosion and deposition. Numerical modeling of sediment transport is the best tool to simulate sediment transport in a water body. This study develops a vertically integrated two-dimensional numerical sediment transport model. Sediment transport is simulated in two parts …

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Hydrodynamic Analysis Of Compliant Journal Bearings, Amith Hanumappa Reddy Jan 2005

Hydrodynamic Analysis Of Compliant Journal Bearings, Amith Hanumappa Reddy

LSU Master's Theses

Compliant journal bearings are commonly used to support radial loads at extreme operating speeds and conditions where conventional bearings cannot operate. The journal and bearing system are supported by a thin lubricant film (gas) due to the hydrodynamic pressure distribution. To predict the bearing performance parameters, the compressible Reynolds equation is solved based on Infinitely Long Approximation (ILA), Finite Analysis (FA) and a new Modified Parabolic Approximation (MPA). The MPA method reduces the classical Reynolds equation to an ordinary differential equation. Appropriate equations and numerical solution are developed for treating a compressible Reynolds equation using MPA. A series of parametric …

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Development And Model Formulation Of Scalable Carbon Nanotube Processes: Hipco And Comocat Process Models, Adedeji Ebenezer Agboola Jan 2005

Development And Model Formulation Of Scalable Carbon Nanotube Processes: Hipco And Comocat Process Models, Adedeji Ebenezer Agboola

LSU Master's Theses

Carbon nanotubes are seamless cylindrical tubes, consisting of carbon atoms arranged in a regular hexagonal structure. It is considered as the ultimate engineering material because of its unique and distinct electronic, mechanical and material characteristics. The discovery of these materials pioneered the nanotechnology revolution, which encompasses a broad and multidisciplinary spectrum, including nanomaterials, nanobiotechnology, and nanoelectronics. Hundreds of published articles of laboratory scale and pilot plant processes were reviewed that describe potential synthesis and post–synthesis purification methods for large scale production of carbon nanotubes. The main production technologies include electric arc discharge, laser vaporization, and catalytic chemical vapor deposition. These …

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Controlled High Pressure Slurry Injection In Water Jetting Applications-A New Approach, Manish Kumar Jan 2005

Controlled High Pressure Slurry Injection In Water Jetting Applications-A New Approach, Manish Kumar

LSU Master's Theses

The ability of an abrasive assisted water jet to cut through rocks and metals has potential applications in the oilfield. However, the size of cutting nozzle has not allowed water jet to be used on commercial scale for drilling reservoir rocks down-hole. Inefficient momentum transfer to abrasive particles from pressurized water and lack of abrasive feed rate control in commercially available units has further discouraged the use of water jet in oil industry. Despite various technical difficulties, immense power of water jet cannot be neglected. Studies have shown that momentum transfer can be improved significantly, if abrasive particles are introduced …

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Simulation Of A Micro Jet Cooling Array, Pierre Montanier Jan 2005

Simulation Of A Micro Jet Cooling Array, Pierre Montanier

LSU Master's Theses

The new generation of electronic devices are more powerful, and they produce more heat. Hence, there is a need for micro cooling systems for removing the heat from these micro chips. This research focused on one micro cooling system-the micro jet cooling array. Some test simulations were made on a single jet cooling system. In addition, the inlet Reynolds number was varied in order to obtain the variation of the heat transfer coefficient. These simulations gave a basic idea of how the impingement cooling method works on the micro jet cooling array. Numerical simulations were made on the actual micro …

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Effect Of Back Belt On Inter-Joint Coordination And Postural Index Value Under Self Selected Manual Lifting Technique, Ashish Dashrathrao Nimbarte Jan 2005

Effect Of Back Belt On Inter-Joint Coordination And Postural Index Value Under Self Selected Manual Lifting Technique, Ashish Dashrathrao Nimbarte

LSU Master's Theses

Over the past decade increasing number of US companies have been encouraging the use of abdominal support as a part of their efforts to reduce the human and economic costs due to back injuries. Back belts are assumed to prevent injuries by restricting posture, increasing intra abdominal pressure, providing psychological effect and relaxing trunk muscle to provide circumferential support around the pelvis ring. This research deals in detail with the posture restriction caused by back belt. Two-dimensional kinematic data was collected from ten subjects using nine marker positions. Angular displacement of nine body angles was compared. The kinematic relationship, posture, …

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Finite Element Modeling Approach And Performance Evaluation Of Fiber Reinforced Polymer Sandwich Bridge Panels, Stanley Onyema Oghumu Jan 2005

Finite Element Modeling Approach And Performance Evaluation Of Fiber Reinforced Polymer Sandwich Bridge Panels, Stanley Onyema Oghumu

LSU Master's Theses

In the USA alone, about 27% of the bridges are classified as structurally deficient or functionally obsolete. Bridge owners are continually investigating methods to effectively retrofit existing bridges, or to economically replace them with new ones. Modern composite materials for structural applications, at one time only in the domain of aerospace engineering, are increasingly making their way into civil engineering applications. In addition to retrofitting current concrete and steel structures using FRP sheets or plates, a great deal of work is being conducted to develop versatile, fully-composite structural bridge systems. To reduce the self-weight and also achieve the necessary stiffness, …

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Semantic Classification Of Rural And Urban Images Using Learning Vector Quantization, Prakash Thulasiraman Jan 2005

Semantic Classification Of Rural And Urban Images Using Learning Vector Quantization, Prakash Thulasiraman

LSU Master's Theses

One of the major hurdles in semantic image classification is that only low-level features can be reliably extracted from images as opposed to higher level features (objects present in the scene and their inter-relationships). The main challenge lies in grouping images into semantically meaningful categories based on the available low-level visual features of the images. It is important that we have a classification method that will handle a complex image dataset with not so well defined boundaries between clusters. Learning Vector Quantization (LVQ) neural networks offer a great deal of robustness in clustering complex datasets. This study presents a semantic …

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Behavior Of Heat Straightened Plates Bent Along The Minor Axis, Manish Sharma Jan 2005

Behavior Of Heat Straightened Plates Bent Along The Minor Axis, Manish Sharma

LSU Master's Theses

The heat straightening method of repair for damaged steel structures has been employed for many years. The method was based on the experience of practitioners. Recent research has given an engineering background for the technique and established certain procedures and guidelines to be followed while using heat straightening. Although a scientific basis has now been established, there still exist some major gaps in the data. Misuse of the heat straightening technique has produced fractures in the steel during repair.There are two parameters that may be keys to limiting fracture sensitivity: degree of damage and application of jacking force stress during …

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Hierarchical Indexing For Region Based Image Retrieval, Eka Aulia Jan 2005

Hierarchical Indexing For Region Based Image Retrieval, Eka Aulia

LSU Master's Theses

Region-based image retrieval system has been an active research area. In this study we developed an improved region-based image retrieval system. The system applies image segmentation to divide an image into discrete regions, which if the segmentation is ideal, correspond to objects. The focus of this research is to improve the capture of regions so as to enhance indexing and retrieval performance and also to provide a better similarity distance computation. During image segmentation, we developed a modified k-means clustering algorithm for image retrieval where hierarchical clustering algorithm is used to generate the initial number of clusters and the cluster …

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Effects Of Magnetic Field On Micro Flames, Sumathi Swaminathan Jan 2005

Effects Of Magnetic Field On Micro Flames, Sumathi Swaminathan

LSU Master's Theses

The effect of a gradient magnetic field on a diffusion micro flame i.e. C3H8/air flame has been systematically studied to comprehend their interaction. A non-uniform magnetic field was produced in the air gap of an electromagnet and the C3H8/air flame corresponding to various flow velocities was subjected to the non-uniform field. The influence of the operating conditions on the fundamental characteristics of the diffusion flame, such as the flame structure, temperature distribution and the morphology of the soot produced in these flames have been thoroughly investigated. The flame structure and its luminosity were found to be influenced and the flame …

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Fuzzifying [Sic] Markov Decision Process, Ahmed Syed Irshad Jan 2005

Fuzzifying [Sic] Markov Decision Process, Ahmed Syed Irshad

LSU Master's Theses

Markov decision processes have become an indispensable tool in applications as diverse as equipment maintenance, manufacturing systems, inventory control, queuing networks and investment analysis. Typically we have a controlled Markov chain on a suitable state space in which transitional probabilities depend on the policy (or decision maker) which comes from a set of possible actions. The main problem of interest would be to find an optimal policy that minimizes the associated cost. Linear Programming has been widely used to find the optimal Markov decision policy. It requires solutions of large systems of simultaneous linear equations. By the fact that the …

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Purification And Structural Characterization Of Caged Dna Oligonucleotides, Brendan Michael Mcadams Jan 2005

Purification And Structural Characterization Of Caged Dna Oligonucleotides, Brendan Michael Mcadams

LSU Master's Theses

“Cage” molecules reversibly block the bioactivity of a target substrate molecule by a photolyzable covalent bond formed at a functional site of the target molecule. The attachment of cage molecules to DNA oligodeoxynucleotides (ODNs) to transiently block bioactivity, and site-specific restoration of bioactivity using targeted light exposure, would enable a new method of control for use in gene therapy, molecular/DNA computing, molecular biology, and drug delivery. The reaction of the cage molecule 1-(4,5-dimethoxy-2-nitrophenyl)diazoethane (DMNPE) with DNA ODNs in an batch reaction yields a mixture of products with varying degrees of caging. Purification and verification of the hypothesized site of DMNPE …

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Improved Watermarking Scheme Using Decimal Sequences, Naveed Shaik Ashfaq Jan 2005

Improved Watermarking Scheme Using Decimal Sequences, Naveed Shaik Ashfaq

LSU Master's Theses

This thesis improves upon the work carried out by Mandhani on decimal sequence watermarking showing that the embedding and decoding algorithms used by Mandhani are not robust. We next specify improvements to these algorithms so that the peak signal to noise ratio (PSNR) is maximized and the distortion introduced in the image due to the embedding is minimized. By exploiting the cross correlation property of decimal sequences, the concept of embedding more than one watermark in the same cover image has been investigated. A comparison between the PSNRs for decimal sequence watermarking and other pseudorandom sequences has been made.

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Photobiological And Thermal Effects Of Uva Light On Cell Culture, Julianne Forman Jan 2005

Photobiological And Thermal Effects Of Uva Light On Cell Culture, Julianne Forman

LSU Master's Theses

The objective of this study is to characterize the photobiological and thermal effects of UVA light on cell cultures. While near-ultraviolet light has been widely used to photoactivate fluorophores and caged compounds in cells, little is known of the long-term biological effects of this light. UVA (320-400nm) photoactivating light has been used for studying fast kinetic processes and is now being employed in higher doses to target longer duration phenomena (e.g. gene expression and silencing). Photoexposure experiments using 365nm light will examine how longer duration and increased UV doses affect photoactivation cell studies. Apoptotic and cellular injury assays have been …

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