Real-time hybrid cutting with dynamic fluid visualization for virtual surgery

It is widely accepted that a reform in medical teaching must be made to meet today's high volume training requirements. Virtual simulation offers a potential method of providing such trainings and some current medical training simulations integrate haptic and visual feedback to enhance procedure learning. The purpose of this project is to explore the capability of Virtual Reality (VR) technology to develop a training simulator for surgical cutting and bleeding in a general surgery

Aeronautical Engineering. A continuing bibliography, supplement 115

This bibliography lists 273 reports, articles, and other documents introduced into the NASA scientific and technical information system in October 1979

Serious Game for Fire Evacuation

Fire safety for buildings has been of increasing concern due to the increase in occupant density in modern-day infrastructures. Efforts have been made by civil engineers to reduce loss in building fire accidents. For example, building codes have been refined to reduce the potential damage caused by fire by enforcing installation of fire detectors, alarm system, ventilation system, and sprinkler system. In addition, current building codes regulate the number of exits as well as the widths and heights of exits to allow an efficient evacuation process if the fire goes out of control. However the fire evacuation training aspect of fire safety is relatively immature. The fire evacuation process is still trained by carrying out traditional fire drills. However, the value of traditional fire drills has been questioned. Traditional fire evacuation drills fail to present a realistic fire environment to the participants. Traditional fire drills fail to raise enough seriousness for the participants since in most cases participants are informed about the drills beforehand. The cost of conducting these traditional fire drills can also be very high. Motivated by the problems faced by traditional fire drills, this research explores a new approach to more effectively and economically train people regarding the fire evacuation process. The new approach is to use a video game to train people for fire evacuation. The whole idea of using games for training and educational purposes falls under the concept of Serious Gaming, which has shown auspicious results in fields of military training, medical training, pilot training, and so on. In the virtual game environment, the fire environment can be simulated and rendered to the players. Doing so can allow the players to experience a more realistic fire environment and hence better prepare them for what to do in response to fire accidents. By setting a proper rewarding system, the game can motivate the players to treat the training more seriously. Also, since the training is carried out in the form of a game, it is more engaging and less costly. Currently, the game has been developed to render smoke and control the movement of agents. In order to make the game environment more realistic, the smoke is simulated and rendered using fire dynamics, and the agent movement is controlled by appropriate pedestrian models. It is worth mentioning that pedestrian modeling is still a relatively immature field of science and this game also serves as a tool for collecting and analyzing data for pedestrian models

Real-Time Ultrasound Simulation for Medical Training and Standardized Patient Assessment

With the increasing role played by ultrasound in clinical diagnostics, ultrasound training in medical education has become more and more important. The clinical routine for ultrasound training is on real patients; therefore monitored and guided examinations involving medical students are quite time-constrained. Furthermore, standardized patients (SPs), who are increasingly used in medical school for teaching and assessing medical students, need to be augmented. These SPs are typically healthy individuals who can not accurately portray the variety of abnormalities that are needed for training especially when medical examinations involve instrument interactions. To augment SPs in a realistically effective way and also address the resourced time constraints for sonography training, a computerized ultrasound simulation is essential for medical education. In this dissertation, I investigate a real-time ultrasound simulation methodology based on a virtual 3-dimentional (3-D) mesh organ. This research has developed the simulation technology to augment SPs with synthetic ultrasound images. I present this methodology and its use in simulating echocardiography. This simulated echocardiogram displays the various oriented sonographs in real time according to the placement of a mock transducer without the need of an actual patient

Heat and Smoke Transport in a Residential-Scale Live Fire Training Facility: Experiments and Modeling

Understanding fire behavior is critical to effective tactical decision making on the fireground, particularly since fireground operations significantly impact the growth and spread of the fire. Computer-based simulation is a flexible, low-cost training methodology with proven success in fields such as pilot training, space, and military applications. Computer-based simulation may enhance fire behavior training and promote effective fireground decision making. This study evaluates the potential of the NIST Fire Dynamics Simulator (FDS) and Smokeview to be utilized as a part of a computer-based fire fighter trainer. Laboratory compartment fire experiments and full-scale fire experiments in a live-fire training facility were both conducted as part of the NIST Multiphase Study on Fire Fighter Safety and the Deployment of Resources. The laboratory experiments characterized the burning behavior of wood pallets to design a repeatable fire for use in the field experiments. The field experiments observed the effects of varying fire fighter deployment configurations on the performance times of fire fighter actions at a live fire training facility. These actions included opening the front door and fire suppression. Because the field experiments simulated numerous fire department responses to a repeatable fire, data were available to evaluate FDS simulation of heat and smoke spread, and changes in the thermal environment after the front door is opened and fire suppressed. In simulating the field experiments, the laboratory-measured heat release rate was used as an input. Given this assumption, this study has two objectives: 1) to determine if simulations accurately spread heat and smoke through a multi-level, multi-compartment live fire training facility 2) to determine if the simulations properly reproduce changes in the thermal environment that result from two typical fire fighter actions: opening the front door and fire suppression. In simulation, heat and smoke spread to measurement locations throughout the test structure at times closely matching experimentally measured times. Predictions of peak temperatures near the ceiling were within approximately 20% for all measurement locations. Hot gas layer temperature and depth were both predicted within 10% of the floor to ceiling height. After the front door was opened, temperature changes near the door at the highest and lowest measurement locations matched with temperature changes in the experiments. After fire suppression, FDS simulated temperature decay at a rate within the range measured in the field experiments and approximated the total rise of the hot gas layer interface in the burn compartment 250 seconds after suppression

Modelling of Multiphase Fluid flow in Heterogeneous Reservoirs

Computational modeling of multiphase fluid flow in highly heterogenous problems with complicated geometries is a challenging problem for reservoir engineers, with a rich research in establishing best methods and approaches. The novelty in this work is centered around the implementation and comparison of simulation results from two software - the open source ICFESRT and the commercial software ECLIPSE - for a two-phase multiphase problem (oilwater) in both simple and complex geometries. The work involves: (a) implementation and comparison of simulation results from the two software on three different, hypothetical but typical geometries; (b) consideration of a real field case and the associated data analysis, rock characterization, and geostatistics of a real field representative of a highly heterogeneous reservoir; and (c) implementation of both software on the real field case for predictions of oil production at the site, and comparison of the simulation results from the two software. The initial comparison of simulation results for was carried out using three hypothetical (but common) geometries, these being: (a) a quarter five spot with one geological layer; (b) the same geometry as in (a) but with a vertical heterogeneity i.e. 5 different geological layers; (c) and lastly a full 5 spot with 5 different geological layers was implemented. Three different mesh resolutions were applied in both software and comparisons were carried out for mesh-independency. The results showed that in all these three scenarios, good agreement was observed between IC-FERST (coarse mesh) and ECLIPSE (fine mesh) with an average percentage difference at the production well ranging between 2.5% and 10.5% for the oil production and 12% and 26% for the water production. Both the ICFERST and ECLIPSE were subsequently implemented on a real, heterogeneous field – which consisted of 25 producing wells and 8 injections wells. Prior to the software implementation, a data analysis and rock characterization was carried out –Using data from the 33 wells. The logging and core data (a total of 30,000 log readings and 1150 core samples) were utilized and a novel rock characterization technique -Balaha Rock Characterization Code- was implemented to allow for the optimal clustering of rock types within the reservoir, The rock characterization resulted in identifying 7 rock types with their unique porosity-hydraulic permeability relationships. Subsequently, geostatistical methods were implemented – which enabled populating the computational cells of the two software with the corresponding reservoir properties (porosity, hydraulic permeability). To achieve the property population into the unstructured computational domain of the ICFERST software, a newly-developed script was written in Matlab and Python. The rock properties data populated on IC-FERST consist of porosity, permeability, relative permeability, capillary pressure and connate water saturation. A further comparison between the IC-FERST simulation results with the corresponding ECLIPSE simulations was carried out – were all simulations were carried out for a period of 40 years. The percentage differences between the two software simulations were estimated for : (i) ten individual production wells and (ii) the total of all production wells. The results showed that a good agreement exists between the IC-FERST and ECLIPSE simulations, with an average percentage difference for the total oil production of 10.5%, the total water production of 26% and the total water injection of 14%. The results for the ten individual wells showed an average percentage difference of 15.5% ranging from 3 to 29% for the oil production in the late time period. Slightly higher differences were observed when the overall period was considered, due to the large difference at the early time period of the simulation. The results indicated that IC-FERST, when incorporating the necessary rock characterization information – which highlight the heterogeneity of the reservoir – can produce results that can compete with the industry standard ECLIPSE. Additional aspects need to be considered within the current real field IC-FERST simulation, the inclusion of possible fractures and faults, as these were incorporated in the computational domain of ECLIPSE. Additional capabilities also still need to be embedded into IC-FERST, such as the incorporation of the fluid density and viscosity variations with pressure and the consideration of the volume factors, in order to enhance its competitiveness with existing commercial reservoirs simulators such as ECLIPSE

Implementation and application of fracture diagnostic tools : fiber optic sensing and diagnostic fracture injection test (DFIT)

Shale reservoirs have drawn much attention in recent years in the oil and gas industry. Hydraulic fracturing is a key technology to extract the trapped hydrocarbon in the shale reservoirs. The complex hydraulic and natural fracture networks enable large contact area between fracture and low-permeability reservoir to enhance the production. The characterization of complex fracture geometry and evaluation of fracture properties are crucial to the fracturing operation design and fractured reservoir simulation. The main approach to a better understanding of fracture and shale reservoir matrix is fracture diagnosis. There are mainly five fracture diagnostic technologies: Distributed Temperature Sensing (DTS), Distributed Acoustic Sensing (DAS), Diagnostic Fracture Injection Test (DFIT), microseismic, and tracer flow-back test. In this study, we mainly focus on the data interpretation model of DTS and DFIT. The current interpretation of DTS data is mostly limited to the qualitative analysis. To enable the quantitative interpretation of DTS data, an in-house comprehensive model is developed to evaluate the fracture properties and geometry. Our model couples fracture, wellbore, and reservoir domain together to capture the full physical process during the production stage. The effects of reservoir parameters, fracture parameters, and fracture geometries on temperature profiling along the wellbore are analyzed with our model. Our forward model could be potentially used to characterize fracture parameters or fracture geometry with history matching. DFIT is consisted of before closure analysis and after closure analysis. The leak-off coefficient, injection efficiency, reservoir matrix permeability, and initial pore pressure can be obtained from DFIT data analysis. In this study, several models for DFIT data interpretation were integrated. A Marcellus shale gas DFIT data is successfully analyzed with our workflow.Petroleum and Geosystems Engineerin

The F-18 High Alpha Research Vehicle: A High-Angle-of-Attack Testbed Aircraft

The F-18 High Alpha Research Vehicle is the first thrust-vectoring testbed aircraft used to study the aerodynamics and maneuvering available in the poststall flight regime and to provide the data for validating ground prediction techniques. The aircraft includes a flexible research flight control system and full research instrumentation. The capability to control the vehicle at angles of attack up to 70 degrees is also included. This aircraft was modified by adding a pitch and yaw thrust-vectoring system. No significant problems occurred during the envelope expansion phase of the program. This aircraft has demonstrated excellent control in the wing rock region and increased rolling performance at high angles of attack. Initial pilot reports indicate that the increased capability is desirable although some difficulty in judging the size and timing of control inputs was observed. The aircraft, preflight ground testing and envelope expansion flight tests are described

Aeronautical Engineering. A continuing bibliography with indexes, supplement 156

This bibliography lists 288 reports, articles and other documents introduced into the NASA scientific and technical information system in December 1982

Learning and Simulation Algorithms for Constraint Physical Systems

This thesis explores two computational approaches to learn and simulate complex physical systems exhibiting constraint characteristics. The target applications encompass both solids and fluids. On the solid side, we proposed a new family of data-driven simulators to predict the behaviors of an unknown physical system by learning its underpinning constraints. We devised a neural projection operator facilitated by an embedded recursive neural network to interactively enforce the learned underpinning constraints and to predict its various physical behaviors. Our method can automatically uncover a broad range of constraints from observation point data, such as length, angle, bending, collision, boundary effects, and their combinations, in the context of a diverse set of physical systems including rigid bodies, ropes, articulated bodies, and multi-object collisions. On the fluid side, we proposed a gauge numerical simulator to model fluid phenomena using Clebsch wave functions. Our method combines the expressive power of Clebsch wave functions to represent coherent vortical structures and the generality of gauge methods to accommodate a broad array of fluid phenomena. We devised a transformed wave function as the system’s gauge variable to improve a fluid simulator’s vorticity generation and preservation ability. We showcase our method by simulating various types of incompressible flow phenomena, including complex vortex filament dynamics, fluids with different obstacles, and surface-tension flow