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- Title
- Strength and Durability of Rice Husk Ash-Modified Concrete in the Marine Environment.
- Creator
- Alvarez, Marcelina, Reddy, Dronnadula V., Florida Atlantic University
- Abstract/Description
-
The purpose of this research project is to compare the strength and durability characteristics of rice husk ash-modified concrete with those of normal concrete in the marine environment. Specimens prepared from concrete mixes with watercementitious ratios of 0.40 and 0.55, and rice husk ash content of 0%, 10%, and 20% were tested. The rice husk ash used was obtained from Agrilectric, power plant located in Lake Charles, Louisiana. The grinding of the ash to particle size of 7-J..tm to 45-J....
Show moreThe purpose of this research project is to compare the strength and durability characteristics of rice husk ash-modified concrete with those of normal concrete in the marine environment. Specimens prepared from concrete mixes with watercementitious ratios of 0.40 and 0.55, and rice husk ash content of 0%, 10%, and 20% were tested. The rice husk ash used was obtained from Agrilectric, power plant located in Lake Charles, Louisiana. The grinding of the ash to particle size of 7-J..tm to 45-J..tm was done by Process Research ORTECH Inc., Ontario, Canada. Strength and durability tests were performed, following ASTM (American Society for Testing and Materials) Standards. The significant fmdings are that the properties and quality of the rice husk ash-modified concrete are as good, if not better than normal concrete.
Show less - Date Issued
- 2006
- PURL
- http://purl.flvc.org/fau/fd/FA00012502
- Subject Headings
- Seawater corrosion, Reinforced concrete--Environmental testing, Concrete--Additives, Rice hulls--Testing, Limekilns--Testing
- Format
- Document (PDF)
- Title
- Storage subsystem workload characterization and synthesis.
- Creator
- Ali, Ahmad A. J., Florida Atlantic University, Mahgoub, Imad
- Abstract/Description
-
In this study, a tool has been developed which traces the storage subsystem workload at the subsystem level. Due to hardware assistance, this tool has very little overhead. This is achieved by incorporating the tracing routine in the microcode of the IBM SCSI adapter. The I/O traces are collected, in realtime, on a PS/2 connected to the modified SCSI adapter via an asynchronous link. These traces are then processed and studied. We have developed a scheme to characterize the workload by...
Show moreIn this study, a tool has been developed which traces the storage subsystem workload at the subsystem level. Due to hardware assistance, this tool has very little overhead. This is achieved by incorporating the tracing routine in the microcode of the IBM SCSI adapter. The I/O traces are collected, in realtime, on a PS/2 connected to the modified SCSI adapter via an asynchronous link. These traces are then processed and studied. We have developed a scheme to characterize the workload by studying the parameters of the traced workload. These parameters include LBA distributions, interarrival time distribution, size distributions, ratios between read requests and write requests, adapter's cache performance, etc. In this study, workload characterization of storage subsystems in OS/2, AIX and NetWare environments was performed. An algorithm for synthesizing of the workload was also developed and implemented as part of this study.
Show less - Date Issued
- 1995
- PURL
- http://purl.flvc.org/fcla/dt/15227
- Subject Headings
- Computer networks--Workload, System design, Computer storage devices
- Format
- Document (PDF)
- Title
- Solids hydrodynamics and heat transfer to in-line and staggered tube banks in large particle fluidized beds.
- Creator
- Darda, Monish M., Florida Atlantic University, Moslemian, Davood
- Abstract/Description
-
A Computer Automated Radioactive Particle Tracking (CARPT) facility was designed and implemented for the investigation of hydrodynamics in two phase flows. This facility was complemented by a versatile fluidized bed facility capable of handling high air flow rates. Solids mean dynamic behavior and heat transfer to internals in a 29.21 cm diameter fluidized bed were investigated for different operating conditions. Different flow parameters like the solids ensemble-averaged velocity, stagnancy...
Show moreA Computer Automated Radioactive Particle Tracking (CARPT) facility was designed and implemented for the investigation of hydrodynamics in two phase flows. This facility was complemented by a versatile fluidized bed facility capable of handling high air flow rates. Solids mean dynamic behavior and heat transfer to internals in a 29.21 cm diameter fluidized bed were investigated for different operating conditions. Different flow parameters like the solids ensemble-averaged velocity, stagnancy and the phase density in the presence of horizontal tubes were determined using the CARPT facility. Local circumferential variations of heat transfer coefficients at the surface of horizontal tubes were measured at different locations in a large particle fluidized bed using a miniature heat transfer probe assembly. The influence of solids hydrodynamics on the heat transfer coefficient in gas-fluidized beds was investigated. The data obtained in the present study was compared to current heat transfer models for large particle gas-fluidized beds.
Show less - Date Issued
- 1990
- PURL
- http://purl.flvc.org/fcla/dt/14576
- Subject Headings
- Heat--Transmission, Hydrodynamics, Fluidization
- Format
- Document (PDF)
- Title
- Sound generated due to vortical flow past a forward facing step.
- Creator
- Gundlapalli, Ravishankar., Florida Atlantic University, Dhanak, Manhar R.
- Abstract/Description
-
The sound field associated with the motion of 2-dimensional finite core vortex past a forward facing step is obtained. A numerical scheme using Contour Dynamics technique and incompressible, inviscid equations of motion is developed to determine the evolution of the structure of the vortex, its path over the step and the radiated sound. An appropriate low-frequency Green's function is derived and the expression for the far field acoustic pressure as formulated by Mohring is used. The vortex...
Show moreThe sound field associated with the motion of 2-dimensional finite core vortex past a forward facing step is obtained. A numerical scheme using Contour Dynamics technique and incompressible, inviscid equations of motion is developed to determine the evolution of the structure of the vortex, its path over the step and the radiated sound. An appropriate low-frequency Green's function is derived and the expression for the far field acoustic pressure as formulated by Mohring is used. The vortex structure evolves in the non-uniform flow in the vicinity of the step and under certain conditions is found to undergo significant deformation of its core structure. The far field acoustic pressure is found to be a strong function of vortex motion in the vicinity of the step. Results for the vortex trajectory and the associated acoustic pressure are presented for a variety of flow parameters.
Show less - Date Issued
- 1992
- PURL
- http://purl.flvc.org/fau/fd/FADT14825
- Subject Headings
- Underwater acoustics, Vortex-motion, Eddies, Hydrodynamics
- Format
- Document (PDF)
- Title
- Software development behavior in small organizations.
- Creator
- Chaudhry, Muhammed Zubair., Florida Atlantic University, Levow, Roy B., Coulter, Neal S.
- Abstract/Description
-
As the software industry continues to mature, best practices have been defined to improve the quality and productivity of software development. Adoption rates of these practices are better understood for large organizations as compared to small standalone organizations. Based on surveys and interviews, this study analyzes the utilization of software development best practices by small software organizations, and the factors that influence different levels of adoption. The results demonstrate...
Show moreAs the software industry continues to mature, best practices have been defined to improve the quality and productivity of software development. Adoption rates of these practices are better understood for large organizations as compared to small standalone organizations. Based on surveys and interviews, this study analyzes the utilization of software development best practices by small software organizations, and the factors that influence different levels of adoption. The results demonstrate that context is the main determinant of adoption, driven by competitive pressures, organizational incentives, and prior exposure to best practices. Consulting firms were influenced by their contractual relationship with the client, which led to more focus on deliverables. Traditional product companies emphasized code management practices, though their focus on domain expertise detracted from software development best practices. Finally, startups were characterized by experienced senior managers who balanced quality assurance against pressures for a quick time to market release.
Show less - Date Issued
- 2001
- PURL
- http://purl.flvc.org/fcla/dt/12787
- Subject Headings
- Computer software--Development, Associations, institutions, etc
- Format
- Document (PDF)
- Title
- SoftBoard: A Web-based application sharing system for distance learning.
- Creator
- Adusumilli, Krishna K., Florida Atlantic University, Chung Hsu, Sam
- Abstract/Description
-
The thesis describes the development of SoftBoard, a Web-based application sharing system. The main goal is to create a convenient tool for conducting virtual office hours for distance education over the Internet. It has been reported in the recent research papers that the current Internet is still not suitable for supporting collaborative tools such as audio/video conferencing and some advanced application sharing features as proclaimed by developers. However the Internet can be used to a...
Show moreThe thesis describes the development of SoftBoard, a Web-based application sharing system. The main goal is to create a convenient tool for conducting virtual office hours for distance education over the Internet. It has been reported in the recent research papers that the current Internet is still not suitable for supporting collaborative tools such as audio/video conferencing and some advanced application sharing features as proclaimed by developers. However the Internet can be used to a lesser degree to fulfill needs of smaller application sharing systems which are not very network bandwidth intensive. SoftBoard is designed to be used over today's Internet, and can be easily invoked from a standard Web browser. It is developed in Java and is implemented using Java's Remote Method Invocation (RMI) for networking. A light pen can be used with SoftBoard to provide a convenient way for creating non-textual contents free hand. The thesis is part of the ongoing research work at Florida Atlantic University's Center for Innovative Distance Education Technologies (CIDET). Research work has been done to validate the present Internet for its capabilities to hold a true distance education program using various available collaborative tools.
Show less - Date Issued
- 1999
- PURL
- http://purl.flvc.org/fcla/dt/15705
- Subject Headings
- Internet in education, Distance education
- Format
- Document (PDF)
- Title
- Static error modeling of sensors applicable to ocean systems.
- Creator
- Ah-Chong, Jeremy Fred., Florida Atlantic University, An, Edgar
- Abstract/Description
-
This thesis presents a method for modeling navigation sensors used on ocean systems and particularly on Autonomous Underwater Vehicles (AUV). An extended Kalman filter was previously designed for the implementation of the Inertial Navigation System (INS) making use of Inertial Measurement Unit (IMU), a magnetic compass, a GPS/DGPS system and a Doppler Velocity Log (DVL). Emphasis is put on characterizing the static sensor error model. A "best-fit ARMA model" based on the Aikake Information...
Show moreThis thesis presents a method for modeling navigation sensors used on ocean systems and particularly on Autonomous Underwater Vehicles (AUV). An extended Kalman filter was previously designed for the implementation of the Inertial Navigation System (INS) making use of Inertial Measurement Unit (IMU), a magnetic compass, a GPS/DGPS system and a Doppler Velocity Log (DVL). Emphasis is put on characterizing the static sensor error model. A "best-fit ARMA model" based on the Aikake Information Criterion (AIC), Whiteness test and graphical analyses were used for the model identification. Model orders and parameters were successfully estimated for compass heading, GPS position and IMU static measurements. Static DVL measurements could not be collected and require another approach. The variability of the models between different measurement data sets suggests online error model estimation.
Show less - Date Issued
- 2003
- PURL
- http://purl.flvc.org/fcla/dt/12977
- Subject Headings
- Underwater navigation, Kalman filtering, Error-correcting codes (Information theory), Detectors
- Format
- Document (PDF)
- Title
- Simulation study of reservation scheme to improve the quality of service in wireless cellular network.
- Creator
- Chokshi, Patheek G., Florida Atlantic University, Ilyas, Mohammad
- Abstract/Description
-
In the present computer age, cellular technology and portable computers are becoming an integral part of the life. Each computer user wants to access the computing resources, irrespective of the location. Because of this need the computing paradigm "Mobile Computing" has assumed a primary role in modern computer communication technology. While dimensioning the network resources, it is very important to know how the users move around the geographical area covered by the cellular network. This...
Show moreIn the present computer age, cellular technology and portable computers are becoming an integral part of the life. Each computer user wants to access the computing resources, irrespective of the location. Because of this need the computing paradigm "Mobile Computing" has assumed a primary role in modern computer communication technology. While dimensioning the network resources, it is very important to know how the users move around the geographical area covered by the cellular network. This knowledge allows us to plan the system resources in order to achieve the QoS required. The major factors that affect the performance, along with the mobility pattern of the mobile user, are the speed at which the user is moving and the load on the network. In this research, we study different types of mobility patterns the user can follow and it's impact on the network services. We have proposed and evaluated a reservation scheme to improve the QoS in the cellular network. The reservation scheme reserves some part of the bandwidth for handoff connections. We have developed simulation programs and have studied three mobility patterns namely leading movement type, random motion, and square-street mobility pattern for measuring the QoS for cellular network. It has been observed from the results that at an average speed of 50 miles per hour with the average loading of the network, a significant improvement in QoS has been achieved for all the mobility patterns by using the reservation scheme.
Show less - Date Issued
- 1999
- PURL
- http://purl.flvc.org/fcla/dt/15706
- Subject Headings
- Wireless communication systems, Mobile computing, Cellular telephone systems
- Format
- Document (PDF)
- Title
- Simulation modeling for hospital emergency department resource analysis.
- Creator
- Amodie, Jeffrey Scott., Florida Atlantic University, Han, Chingping (Jim)
- Abstract/Description
-
Hospital Emergency Departments are forced to operate under many unknown conditions. Therefore, determining the appropriate staffing requirements of an emergency department can be a difficult task. The objective herein is to develop a procedure for assembling a simulation model, to be used as a tool for determining adequate resource requirements for various situations encountered in an emergency department of a hospital. The model will consider variables such as patient arrival rates, types of...
Show moreHospital Emergency Departments are forced to operate under many unknown conditions. Therefore, determining the appropriate staffing requirements of an emergency department can be a difficult task. The objective herein is to develop a procedure for assembling a simulation model, to be used as a tool for determining adequate resource requirements for various situations encountered in an emergency department of a hospital. The model will consider variables such as patient arrival rates, types of injuries, duration of treatment for each specific injury, available resources, etc. It is expected that the use of such a model will help emergency department managers plan for adequate resources to meet the needs of the community being served.
Show less - Date Issued
- 1995
- PURL
- http://purl.flvc.org/fcla/dt/15216
- Subject Headings
- Hospitals--Emergency service, Hospitals--Emergency service--Utilization--Simulation methods, Hospitals--Staff
- Format
- Document (PDF)
- Title
- Simultaneous pressure-temperature measurements in a heat pipe.
- Creator
- Jayanth, Madhavan., Florida Atlantic University, Abtahi, Amir
- Abstract/Description
-
When a heat pipe operates with a large temperature difference between the two ends, the vapor liquid combination is not in thermodynamic equilibrium. The experiments showed that the vapor liquid mixture is in a higher state of saturation at the condenser as compared to other sections of the pipe. Correlations were obtained that relate the coefficient of thermal coupling alpha to the evaporator flux and mass of NCG (non-condensable gas). As mass of NCG is increased in the heat pipe, the...
Show moreWhen a heat pipe operates with a large temperature difference between the two ends, the vapor liquid combination is not in thermodynamic equilibrium. The experiments showed that the vapor liquid mixture is in a higher state of saturation at the condenser as compared to other sections of the pipe. Correlations were obtained that relate the coefficient of thermal coupling alpha to the evaporator flux and mass of NCG (non-condensable gas). As mass of NCG is increased in the heat pipe, the thermal coupling coefficient alpha decreases. The evaporator heat flux is directly proportional to alpha. The coefficient alpha is related to the pressures and temperatures at the evaporator, condenser and the adiabatic sections. In conclusion, for heat pipes that do not operate in thermodynamic equilibrium, correlations were obtained between the operating conditions of the heat pipe, the evaporator heat flux and the mass of NCG.
Show less - Date Issued
- 1997
- PURL
- http://purl.flvc.org/fcla/dt/15435
- Subject Headings
- Heat pipes, Temperature measurements, Pressure--Measurements
- Format
- Document (PDF)
- Title
- Stress ratio, temperature and microstructural effects on the fatigue crack propagation threshold of titanium alloys.
- Creator
- Dauven, Joseph R., Florida Atlantic University, Salivar, Gary C.
- Abstract/Description
-
This research investigated the effects of stress ratio, temperature and microstructure on the near-threshold fatigue crack growth characteristics of three differently processed titanium alloys. The materials investigated included one hot-worked Ti-6Al-2Sn-4Zr-2Mo alloy, one cast Ti-6Al-4V alloy and one cast Ti-6Al-2Sn-4Zr-2Mo alloy. It was found that overall crack closure could account for apparent differences in fatigue threshold for stress ratios up to about 0.7. Tests run at stress ratios...
Show moreThis research investigated the effects of stress ratio, temperature and microstructure on the near-threshold fatigue crack growth characteristics of three differently processed titanium alloys. The materials investigated included one hot-worked Ti-6Al-2Sn-4Zr-2Mo alloy, one cast Ti-6Al-4V alloy and one cast Ti-6Al-2Sn-4Zr-2Mo alloy. It was found that overall crack closure could account for apparent differences in fatigue threshold for stress ratios up to about 0.7. Tests run at stress ratios of 0.9, however, showed a noticeably lower fatigue threshold. Crack closure was not able to account for differences due to elevated temperature. Fractographic evidence is also presented which shows the extremely beneficial effects of larger grain size on the fatigue threshold through crack branching, deflection and bifurcation.
Show less - Date Issued
- 1991
- PURL
- http://purl.flvc.org/fcla/dt/14772
- Subject Headings
- Titanium alloys--Fatigue--Testing, Materials--Fatigue--Testing
- Format
- Document (PDF)
- Title
- Stress corrosion cracking susceptibility of engineering alloys in acidified seawater.
- Creator
- Campaignolle, Xavier., Florida Atlantic University, Lipka, Stephen M.
- Abstract/Description
-
Experiments were conducted to determine the stress corrosion cracking (SCC) susceptibility of various corrosion-resistant alloys which included: 17-4 PH, INCONEL 718 and A286. These alloys were studied for different aging (heat) treatments. Slow strain rate tests (extension rate = 4.7 x 10^-5 mm/s) were performed on each alloy in four different environments; including air and natural seawater acidified with reagent grade hydrochloric acid to a pH of 0.1, 1 and 3. During the experiments, the...
Show moreExperiments were conducted to determine the stress corrosion cracking (SCC) susceptibility of various corrosion-resistant alloys which included: 17-4 PH, INCONEL 718 and A286. These alloys were studied for different aging (heat) treatments. Slow strain rate tests (extension rate = 4.7 x 10^-5 mm/s) were performed on each alloy in four different environments; including air and natural seawater acidified with reagent grade hydrochloric acid to a pH of 0.1, 1 and 3. During the experiments, the load versus time and the open circuit potential were monitored. Various parameters such as time-to-failure, energy-to-failure, maximum or failure stress and reduction-in-area were calculated in order to determine SCC susceptibility. Fractography using SEM was conducted to confirm whether any SCC occurred and, if so, to identify its mode (intergranular or transgranular). Limited potentiodynamic studies were also completed to evaluate the passive behavior of these alloys. The results are discussed in terms of the SCC susceptibility and the nature of the cracking. An attempt was also made to correlate alloy microstructure, slow strain rate test parameters and passivation behavior with SCC susceptibility.
Show less - Date Issued
- 1991
- PURL
- http://purl.flvc.org/fcla/dt/14756
- Subject Headings
- Stress corrosion, Alloys--Stress corrosion, Metals--Stress corrosion
- Format
- Document (PDF)
- Title
- The Use of Multiple Tracers to Determine the Impact of Septic Tanks on the Water Quality of Urban and Rural Coastal Environments.
- Creator
- Bocca, Thais Sepulveda, Meeroff, Daniel E., Florida Atlantic University
- Abstract/Description
-
Multiple tracers, such as DO, ammonia, TN, TOC, E. coli, TC, and Enterococcus were analyzed in order to identify and characterize trends in coastal water quality. This study focused on three factors; wastewater disposal and treatment alternative; season; and human population density. Samples were collected in representative sites of urban Broward County and of rural Taylor County, FL, for pair-wise comparison. Sites included areas connected to the public sewer network and served by on-site...
Show moreMultiple tracers, such as DO, ammonia, TN, TOC, E. coli, TC, and Enterococcus were analyzed in order to identify and characterize trends in coastal water quality. This study focused on three factors; wastewater disposal and treatment alternative; season; and human population density. Samples were collected in representative sites of urban Broward County and of rural Taylor County, FL, for pair-wise comparison. Sites included areas connected to the public sewer network and served by on-site treatment and disposal system (OSTDS). Sampling activities were conducted through seasonal low and seasonal high water table elevation (SLWT and SHWT), and always on slack to outgoing tide. Different statistical tests were performed, including: t-Tests, correlation analysis, principal component analysis (PCA), and analysis of variance (ANOVA). Results suggested that water quality is lower: in urban sites compared to rural sites; in OSTDS sites compared to sewered areas; and SHWT compared to SLWT.
Show less - Date Issued
- 2007
- PURL
- http://purl.flvc.org/fau/fd/FA00012505
- Subject Headings
- Water quality management--Florida, Coastal zone management--Florida, Environmental monitoring--Florida
- Format
- Document (PDF)
- Title
- SIMULATED NORTH SEA SPECTRUM FATIGUE ON WELDED STEEL IN FLOWING SEA WATER.
- Creator
- Clark, A. M., Florida Atlantic University, Hartt, William H.
- Abstract/Description
-
Reverse bend, uniform stress beam specimens of ABS DH-32 steel were subjected to fatigue cycles of randomly generated amplitude in a sea water environment to determine the effect of narrow band spectrum loading on cycles to failure. The loading spectrum was the C/12/20 spectrum, developed at the National Engineering Laboratory in Scotland to simulate the severe conditions of the North Sea. Some misinformation which has been published by NEL and other& regarding ~he C/12/20 spectrum is...
Show moreReverse bend, uniform stress beam specimens of ABS DH-32 steel were subjected to fatigue cycles of randomly generated amplitude in a sea water environment to determine the effect of narrow band spectrum loading on cycles to failure. The loading spectrum was the C/12/20 spectrum, developed at the National Engineering Laboratory in Scotland to simulate the severe conditions of the North Sea. Some misinformation which has been published by NEL and other& regarding ~he C/12/20 spectrum is addressed. A number ot means for presenting random amplitude cycles to failure data in the form of an SN plot are discussed. A means for taking into account fatigue test cycling rate in failure predictions is proposed, and the results of the freely corroding specimens of this investigation conform to the proposed technique. The random amplitude specimens exhibited reduced fatigue lives compared with similar specimens of an earlier constant amplitude investigation.
Show less - Date Issued
- 1983
- PURL
- http://purl.flvc.org/fcla/dt/14153
- Subject Headings
- Steel--Fatigue, Steel--Stress corrosion
- Format
- Document (PDF)
- Title
- SIMULATION STUDY OF FLOW-CONTROL IN A TOKEN-RING LOCAL AREA NETWORK.
- Creator
- BALACHANDRAN, CHITRA., Florida Atlantic University, Ilyas, Mohammad
- Abstract/Description
-
This thesis deals with simulation of flow control in token-ring local area networks. The primary emphasis of this simulation study is to observe the effects of token holding time on the performance of the network. Token holding time is adjusted to account for two types of service disciplines: gated and limited. Network performance for these two service disciplines is compared to determine which one of the two gives a relatively better performance. Besides throughput and delay, a more compact...
Show moreThis thesis deals with simulation of flow control in token-ring local area networks. The primary emphasis of this simulation study is to observe the effects of token holding time on the performance of the network. Token holding time is adjusted to account for two types of service disciplines: gated and limited. Network performance for these two service disciplines is compared to determine which one of the two gives a relatively better performance. Besides throughput and delay, a more compact form of performance measure called "power", has also been used in the study . Power is simply a ratio of throughput and delay . This study has shown that the token holding time has a significant effect on the performance of a local area network . Simulation results of this study are presented in terms of throughput, delay, power, token circulation time and efficiency/overhead versus offered load. The results are presented in the form of graphs.
Show less - Date Issued
- 1986
- PURL
- http://purl.flvc.org/fcla/dt/14311
- Subject Headings
- Local area networks (Computer networks)--Simulation methods
- Format
- Document (PDF)
- Title
- THE SPECIFIC ACOUSTIC IMPEDANCE OF FERROMANGANESE NODULES AT EIGHT KILOHERTZ.
- Creator
- GARDNER, DAVID LEE, Florida Atlantic University, Davidson, J. Blaine
- Abstract/Description
-
Ferromanganese nodules are small, irregular lumps of precipitated metal oxides composed primarily of manganese, iron, copper, cobalt, and nickel which accrete in deep ocean environments. The nodules have mining value and commercial recovery is expected in the near future. As present techniques for the detection and evaluation of ferromanganese nodule deposits are cumbersome and time consuming, an investigation of the specific acoustic impedance of the nodules is conducted in an effort to...
Show moreFerromanganese nodules are small, irregular lumps of precipitated metal oxides composed primarily of manganese, iron, copper, cobalt, and nickel which accrete in deep ocean environments. The nodules have mining value and commercial recovery is expected in the near future. As present techniques for the detection and evaluation of ferromanganese nodule deposits are cumbersome and time consuming, an investigation of the specific acoustic impedance of the nodules is conducted in an effort to determine the feasibility of surveying ferromanganese nodule deposits via side-scan sonar techniques. An acoustic transmission line (impedance tube) is utilized to investigate the specific acoustic impedance of the ferromanganese nodule samples. The accuracy of the experimental technique is evaluated using a steel reference cylinder. Results of the tests (on the ferromanganese samples) indicate that the specific acoustic impedance of a typical ferromanganese nodule sample is 2.07 +- .15 x 106 Rayls. Suggestions for future investigations are also presented.
Show less - Date Issued
- 1976
- PURL
- http://purl.flvc.org/fcla/dt/13822
- Subject Headings
- Ferromanganese--Analysis, Acoustic impedance--Instruments
- Format
- Document (PDF)
- Title
- SHIP MOTION PREDICTION USING AUTO REGRESSIVE MOVING AVERAGE METHOD (NAVAL ARCHITECTURE, OFFSHORE TECHNOLOGY, DYNAMIC POSITIONING).
- Creator
- CHANDRASEKHARAN, CHANDRAMOHAN., Florida Atlantic University, Lin, Newman K.
- Abstract/Description
-
The time series method of Auto Regressive Moving Average (ARMA) is applied to the problem of real time ship motion prediction. The theory of Scalar input Scalar output ARMA (n, n-1) model and the same extended to multiple series as vector, ARMAV model have been concisely presented. The field experimental procedure for roll measurement of vessel at sea and barge model test procedure for heave and pitch measurements are discussed. The time series data of roll is analysed as a scalar ARMA (n, n...
Show moreThe time series method of Auto Regressive Moving Average (ARMA) is applied to the problem of real time ship motion prediction. The theory of Scalar input Scalar output ARMA (n, n-1) model and the same extended to multiple series as vector, ARMAV model have been concisely presented. The field experimental procedure for roll measurement of vessel at sea and barge model test procedure for heave and pitch measurements are discussed. The time series data of roll is analysed as a scalar ARMA (n, n-1) model and the results of prediction are presented. The model test data of heave, pitch and wave were analysed as ARMAV (n,n-1) vector model and the results are presented. The model test and experimental results demonstrate the feasibility of ARMA modeling procedure as a valuable tool in the area of real time ship motion prediction.
Show less - Date Issued
- 1985
- PURL
- http://purl.flvc.org/fcla/dt/14246
- Subject Headings
- Motion study, Marine engineering
- Format
- Document (PDF)
- Title
- Thrust Response of a Vectored-Thruster Unmanned Underwater Vehicle.
- Creator
- Ackermann, Lloyd E. J., von Ellenrieder, Karl, Florida Atlantic University
- Abstract/Description
-
Towing tank/water flume experiments are conducted to characterize the dynamics of a Remotely-Piloted Unmanned Underwater Vehicle (RPUUV) propelled by a vectored-thruster system. Force and torque measurements are used to determine the coefficients of drag, lift, yaw-moment and thrust of the vehicle as a function of the vehicle yaw angle and the vectored-thruster rudder angle. Simultaneously, particle Image Velocimetry (PIV) measurements of the propeller inlet flow are also performed to examine...
Show moreTowing tank/water flume experiments are conducted to characterize the dynamics of a Remotely-Piloted Unmanned Underwater Vehicle (RPUUV) propelled by a vectored-thruster system. Force and torque measurements are used to determine the coefficients of drag, lift, yaw-moment and thrust of the vehicle as a function of the vehicle yaw angle and the vectored-thruster rudder angle. Simultaneously, particle Image Velocimetry (PIV) measurements of the propeller inlet flow are also performed to examine the variation of flow conditions at the propeller inlet with rudder angle. The tests are conducted at 0.150 rnls, 0.300 rnls, 0.515 rnls and 0.773 rnls. While the measured drag coefficient is slightly higher than predicted by theory at low Reynolds number (1.44 x10^5 and 2.88 x10^5), the hydrodynamic coefficients data are expected to be useful in predicting the response of vehicles in the field. Additionally, the magnitude of the thrust vector varies nonlinearly with rudder angle and for nonzero rudder angles the thrust vector does not point in the same direction as the thruster axis.
Show less - Date Issued
- 2007
- PURL
- http://purl.flvc.org/fau/fd/FA00012500
- Subject Headings
- Naval architecture, Oceanographic submersibles--Hydrodynamics, Vibration (Marine engineering)
- Format
- Document (PDF)
- Title
- Thermocline tracking using an upgraded ocean explorer autonomous underwater vehicle.
- Creator
- Clabon, Mathieu., Florida Atlantic University, Dhanak, Manhar R.
- Abstract/Description
-
This thesis addresses the problem of tracking a thermocline---a layer of water showing an intense vertical temperature gradient---with an Autonomous Underwater Vehicle (AUV). One of Florida Atlantic University's Ocean Explorer (OEX) AUV has been upgraded, as part of the work described here, by integration of a standard and convenient software interface, and used in several thermocline survey experiments aimed at gathering oceanographic data relevant to thermoclines. A tool that simulates the...
Show moreThis thesis addresses the problem of tracking a thermocline---a layer of water showing an intense vertical temperature gradient---with an Autonomous Underwater Vehicle (AUV). One of Florida Atlantic University's Ocean Explorer (OEX) AUV has been upgraded, as part of the work described here, by integration of a standard and convenient software interface, and used in several thermocline survey experiments aimed at gathering oceanographic data relevant to thermoclines. A tool that simulates the longitudinal motion of the OEX through a water slice, whose temperature map is read using a simulated temperature and depth sensor, has been developed. Using this tool and information from at-sea experiments, several control methods for the OEX to track a thermocline were analyzed. In particular, two different algorithms were implemented and tested by simulation. Overall, two control algorithms have been validated, and it will soon be possible to provide the AUV with a thermocline tracking capability.
Show less - Date Issued
- 2003
- PURL
- http://purl.flvc.org/fcla/dt/13025
- Subject Headings
- Thermoclines (Oceanography), Oceanographic submersibles--Computer simulation, Underwater navigation
- Format
- Document (PDF)
- Title
- Time-step optimal broadcasting in mesh networks with minimum total communication distance.
- Creator
- Cang, Songluan., Florida Atlantic University, Wu, Jie
- Abstract/Description
-
We propose a new minimum total communication distance (TCD) algorithm and an optimal TCD algorithm for broadcast in a 2-dimensional mesh (2-D mesh). The former generates a minimum TCD from a given source node, and the latter guarantees a minimum TCD among all the possible source nodes. These algorithms are based on a divide-and-conquer approach where a 2-D mesh is partitioned into four submeshes of equal size. The source node sends the broadcast message to a special node called an eye in each...
Show moreWe propose a new minimum total communication distance (TCD) algorithm and an optimal TCD algorithm for broadcast in a 2-dimensional mesh (2-D mesh). The former generates a minimum TCD from a given source node, and the latter guarantees a minimum TCD among all the possible source nodes. These algorithms are based on a divide-and-conquer approach where a 2-D mesh is partitioned into four submeshes of equal size. The source node sends the broadcast message to a special node called an eye in each submesh. The above procedure is then recursively applied in each submesh. These algorithms are extended to a 3-dimensional mesh (3-D mesh), and are generalized to a d-dimensional mesh or torus. In addition, the proposed approach can potentially be used to solve optimization problems in other collective communication operations.
Show less - Date Issued
- 1999
- PURL
- http://purl.flvc.org/fcla/dt/15647
- Subject Headings
- Computer algorithms, Parallel processing (Electronic computers), Computer architecture
- Format
- Document (PDF)