Preliminary design of a 100 kW turbine generator

The National Science Foundation and the Lewis Research Center have engaged jointly in a Wind Energy Program which includes the design and erection of a 100 kW wind turbine generator. The machine consists primarily of a rotor turbine, transmission, shaft, alternator, and tower. The rotor, measuring 125 feet in diameter and consisting of two variable pitch blades operates at 40 rpm and generates 100 kW of electrical power at 18 mph wind velocity. The entire assembly is placed on top of a tower 100 feet above ground level

Preliminary candidate advanced avionics system for general aviation

An integrated avionics system design was carried out to the level which indicates subsystem function, and the methods of overall system integration. Sufficient detail was included to allow identification of possible system component technologies, and to perform reliability, modularity, maintainability, cost, and risk analysis upon the system design. Retrofit to older aircraft, availability of this system to the single engine two place aircraft, was considered

Advanced flight control system study

The architecture, requirements, and system elements of an ultrareliable, advanced flight control system are described. The basic criteria are functional reliability of 10 to the minus 10 power/hour of flight and only 6 month scheduled maintenance. A distributed system architecture is described, including a multiplexed communication system, reliable bus controller, the use of skewed sensor arrays, and actuator interfaces. Test bed and flight evaluation program are proposed

Integrated Application of Active Controls (IAAC) technology to an advanced subsonic transport project: Current and advanced act control system definition study. Volume 2: Appendices

The current status of the Active Controls Technology (ACT) for the advanced subsonic transport project is investigated through analysis of the systems technical data. Control systems technologies under examination include computerized reliability analysis, pitch axis fly by wire actuator, flaperon actuation system design trade study, control law synthesis and analysis, flutter mode control and gust load alleviation analysis, and implementation of alternative ACT systems. Extensive analysis of the computer techniques involved in each system is included

Deep Space Network information system architecture study

The purpose of this article is to describe an architecture for the Deep Space Network (DSN) information system in the years 2000-2010 and to provide guidelines for its evolution during the 1990s. The study scope is defined to be from the front-end areas at the antennas to the end users (spacecraft teams, principal investigators, archival storage systems, and non-NASA partners). The architectural vision provides guidance for major DSN implementation efforts during the next decade. A strong motivation for the study is an expected dramatic improvement in information-systems technologies, such as the following: computer processing, automation technology (including knowledge-based systems), networking and data transport, software and hardware engineering, and human-interface technology. The proposed Ground Information System has the following major features: unified architecture from the front-end area to the end user; open-systems standards to achieve interoperability; DSN production of level 0 data; delivery of level 0 data from the Deep Space Communications Complex, if desired; dedicated telemetry processors for each receiver; security against unauthorized access and errors; and highly automated monitor and control

Optical wireless data transfer for rotor detection and diagnostics

A special application of optical wireless data transfer, namely on-line monitoring and diagnostic of rotors in turbines and engines, has been considered in this thesis. In this application, to maintain line of sight, i.e. data transfer, between a sensor placed on a rotating component inside the turbine and a monitoring point placed in a fixed position outside the turbine, a periodic fast fading channel is generated, which gives the transceivers more flexibility regarding their mounting location. The communication in such a channel is affected by the intermittency and variation of the signal power, which produces a unique channel condition that influences the performance of the optical transceiver. To investigate the channel condition and the error rate of the periodic fast fading channel with signal fluctuation, a model is developed to simulate the optical channel by considering the variation of signal power as a result of the change in the relative position of the photodiode with respect to the Lambertian radiation pattern of the LED, in a simplified linear geometry. The error rate is estimated using the Saddlepoint approximation on a specific threshold strategy. The results show that the channel can afford the sensor data transmission and the performance can be improved by modifying several parameters, such as geometrical distance, transmitter power and load resistor. Compared to a normal channel, a higher load resistor on the photodiode front end has the advantage of decreasing the noise level and increasing the data capacity in the fast fading channel. The analysis of the automatic gain control amplifier indicates that a higher load resistor needs a lower loop gain and from the model of the Transimpedance amplifier (TIA), the bandwidth extension from the amplifier is more significant for a higher resistor. In addition to the theoretical model, an experimental setup is built to emulate the channel in practice. The degree of similarity between the experimental setup and the theoretical model of the channel is estimated from the comparison of the generated communication windows. Since it has been found that differences exist in the duration of the communication window and the variation of the signal power, scaling factors to ensure their compatibility have been derived. Transceiver hardware which implemented the modelled functionality has been developed and a protocol to establish the communication with the required error rate has been proposed. Using the hardware implementation, a detection method for both rising and falling edges of the signal pulses and a threshold strategy have been demonstrated. The device power consumption is also estimated. What is more, the electromagnetic environment of a squirrel cage motor is simulated using the finite element method to investigate the interference and the possibility of providing power to the IR communication devices using power scavenging. In the conclusion, the key findings of the thesis are summarised. A solution is proposed for sensor data transfer using an optical channel for rotor monitoring applications, which involves the design of the IR transceiver, the implementation of the developed protocol and the power consumption estimation

A FIRE PROTECTION AND LIFE SAFETY ANALYSIS OF AN OUPATIENT HEALTHCARE SYSTEM BUILDING

The subject building of the report is an outpatient healthcare system building that is a two stories in height and 184,670 SF building. This building offers primary, specialty, and mental health outpatient care to patients throughout its state of location. The facility is a mixed occupancy building with business as the primary occupancy, a surgery suite that classifies as an ambulatory health care occupancy, and assembly uses in the conference rooms, kitchen, and canteen. The Authority Having Jurisdiction (AHJ) has adopted the National Fire Codes (NFC) published by the National Fire Protection Association (NFPA), and throughout this report, the life safety features of the building are assessed against the requirements of Life Safety Code, NFPA 101. The facility is fully sprinklered, with sprinklers appearing to be provided in all areas. There is also an analog addressable fire alarm system that is electrically supervised by a central station monitoring service. Per NFPA 220, Standard on Types of Building Construction, Table 4.1.1 Fire Resistance Ratings for Type I through Type V Construction (hour), this facility appears to be constructed in accordance with the requirements of a Construction Type II (000) rating. The NFPA Type II (000) rating corresponds to an IBC Construction Type IIB. In the following analysis, the facility was evaluated from both prescriptive and performance based design perspectives. The total occupant load for the facility was calculated as 3390 persons in accordance with NFPA 101 Chapter 7. Most spaces were determined to have adequate exit capacity. However, the canteen only has one valid exit and does not meet the required two exits per NFPA 101 for assembly occupancies. All other floors and spaces were determined to have adequate number of exits, separation of exits, and measured travel distances as required by NFPA 101. Code discrepancies were also discovered for fire detection and notification. A discrepancy was discovered between the mounting heights of manual pull stations required by NFPA 72 and those of the fire alarm and detection shop drawings. Pull station placement should be verified. Notification devices in the mechanical penthouses appear to be undersized from a visual notification perspective. Further, audible notification devices in these mechanical penthouses may also be undersized. Field verification of the existing ambient sound levels should be performed. The facility is fully sprinklered, with sprinklers appearing to be provided in all areas. Most of the facility is protected by an automatic wet sprinkler suppression system. There is a small dry sprinkler system located at the loading dock, where the system is subject to freezing conditions. The system appears to have been designed per the AHJ’s Fire Protection Design Manual and NFPA 13-2003. The flow and pressure at the base of the riser (BOR) required to meet the sprinkler system demand is 273.3 gpm and 67.6 psi. The hose stream allowance was previously determined to be 250 gpm. Therefore, the total system demand is 523 gpm at 67.6 PSI. This value exceeds the available water supply of a static pressure of 62 psi, a residual pressure of 20 psi, and 1940 gallons of flow. A computer based analysis should be performed to refine the understanding of the complex hydraulics at the facility. The first floor occupant load was calculated to be 839 persons. Using the hydraulic approximation, the egress time for the first floor was evaluated. If all of the 839 occupants on the first floor start evacuation at the same time, the persons on the first floor will require approximately 1.23 minutes to pass through the exit. The total minimum evacuation time for the 839 persons located on floor 1 is estimated at 5.1 minutes. The second floor occupant load was calculated to be 1210 persons. The second floor exit capacity was calculated to be 1231 persons, which just exceeds the second floor occupant load of 1210 persons. The total minimum evacuation time for the 1231 persons located on floor 2 is estimated at 8.2 minutes. The assumptions used in hydraulic approximation model all tend to optimize egress times and therefore will tend to underestimate actual egress times. The occupant characteristics of these user groups within the facility’s building population were reviewed, and the key characteristics of the groups were evaluated. Since the purpose of this outpatient clinic is to provide medical care to patients, a conservative approach is necessary to protect occupants that may have preexisting medical conditions. Employees regularly participate in fire drills and can typically be expected to efficiently respond to the fire alarm system and start evacuating. However, careful consideration of pre-movement times is especially important with employees as they can be prone to social influence, and procedural requirements. Patients are the most likely to have an issue perceiving an alarm, interpreting the alarm, and deciding on a course of action. Three different design fires were evaluated for this facility. Design Fire #1 investigates the impact of large fuel load of palletized computer equipment on egress in a first floor corridor. Egress is expected to be highly compromised. This design fire is similar to NFPA 101 5.5.3.2 Design Fire Scenario 2 which has the characteristics of an ultrafast developing fire, in the primary means of egress. Design Fire #2 investigates the impact of a Christmas Tree in the building’s main atrium. This fire offers the opportunity to evaluate the impact of a real life fuel load on one of the primary egress paths. This design fire is similar to NFPA 101 5.5.3.1 Design Fire Scenario 1 and is an occupancy specific fire representative of a typical fire for the occupancy. Design Fire #3 evaluates the impact of a large fuel load of furniture in a storage room that is adjacent to the facilities 6 combinable conference rooms. The worst-case scenario for this space is the potential for migration into the adjacent hallway and affecting egress for the nearby conference rooms. This design fire is similar to NFPA 101 5.5.3.3 Design Fire Scenario 3 which includes a fire that starts in a normally unoccupied room, potentially endangering a large number of occupants in a large room or other area. Performance criteria for tenability was investigated, and reference values were proposed. The selected tenability criteria include 13 m for visibility, an FED of 1 for Carbon Monoxide, 60 °C for exposure temperature, and 1.7 kW·m-2 for radiant heat exposure. Fire Dynamics Simulator (FDS) was used to model Design Fire #1, which presented an abnormally large fuel load of computer equipment in a hallway outside of the Supply Chain Management office. This fire provides an ultrafast developing fire, in the primary means of egress, and addresses a concern regarding a reduction in the number of available means of egress. Visibility is the first tenability criteria to be reached in a time frame of 92 seconds, followed by exposure temperature at 105 seconds. The reality of this ultrafast fire is that egress for the Supply Chain Management Office will be severely compromised, and may not provide ample time for the occupants of the Supply Chain Management Office to escape. Further modeling could be performed with additional information on the building\u27s construction materials, ventilation systems, and fire suppression systems. The response of the fire suppression system, and its effectiveness on the fuel load should be evaluated and could potentially help egress from the Supply Chain Management Office. Since the calculated Required Safe Egress Time (RSET) is calculated 12.72 minutes, and the Available Safe Egress Time (ASET) is 92 seconds, egress for the Supply Chain Management Office can be expected to be compromised. Based on the results of modeling Design Fire #1, it is recommended to relocate the commodity to a warehouse. The surveyed fuel load is inappropriate for an exit corridor in a Business Occupancy

Autonomous Flight, Fault, and Energy Management of the Flying Fish Solar-Powered Seaplane.

The Flying Fish autonomous unmanned seaplane is designed and built for persistent ocean surveillance. Solar energy harvesting and always-on autonomous control and guidance are required to achieve unattended long-term operation. This thesis describes the Flying Fish avionics and software systems that enable the system to plan, self-initiate, and autonomously execute drift-flight cycles necessary to maintain a designated watch circle subject to environmentally influenced drift. We first present the avionics and flight software architecture developed for the unique challenges of an autonomous energy-harvesting seaplane requiring the system to be: waterproof, robust over a variety of sea states, and lightweight for flight. Seaplane kinematics and dynamics are developed based on conventional aircraft and watercraft and upon empirical flight test data. These models serve as the basis for development of flight control and guidance strategies which take the form of a cyclic multi-mode guidance protocol that smoothly transitions between nested gain-scheduled proportional-derivative feedback control laws tuned for the trim conditions of each flight mode. A fault-tolerant airspeed sensing system is developed in response to elevated failure rates arising from pitot probe water ingestion in the test environment. The fault-tolerance strategy utilizes sensor characteristics and signal energy to combine redundant sensor measurements in a weighted voting strategy, handling repeated failures, sensor recovery, non-homogenous sensors, and periods of complete sensing failure. Finally, a graph-based mission planner combines models of global solar energy, local ocean-currents, and wind with flight-verified/derived aircraft models to provide an energy-aware flight planning tool. An NP-hard asymmetric multi-visit traveling salesman planning problem is posed that integrates vehicle performance and environment models using energy as the primary cost metric. A novel A* search heuristic is presented to improve search efficiency relative to uniform cost search. A series of cases studies are conducted with surface and airborne goals for various times of day and for multi-day scenarios. Energy-optimal solutions are identified except in cases where energy harvesting produces multiple comparable-cost plans via negative-cost cycles. The always-on cyclic guidance/control system, airspeed sensor fault management algorithm, and the nested-TSP heuristic for A* are all critical innovation required to solve the posed research challenges.Ph.D.Aerospace EngineeringUniversity of Michigan, Horace H. Rackham School of Graduate Studieshttp://deepblue.lib.umich.edu/bitstream/2027.42/91453/1/eubankrd_1.pd

Impact of Random Deployment on Operation and Data Quality of Sensor Networks

Several applications have been proposed for wireless sensor networks, including habitat monitoring, structural health monitoring, pipeline monitoring, and precision agriculture. Among the desirable features of wireless sensor networks, one is the ease of deployment. Since the nodes are capable of self-organization, they can be placed easily in areas that are otherwise inaccessible to or impractical for other types of sensing systems. In fact, some have proposed the deployment of wireless sensor networks by dropping nodes from a plane, delivering them in an artillery shell, or launching them via a catapult from onboard a ship. There are also reports of actual aerial deployments, for example the one carried out using an unmanned aerial vehicle (UAV) at a Marine Corps combat centre in California -- the nodes were able to establish a time-synchronized, multi-hop communication network for tracking vehicles that passed along a dirt road. While this has a practical relevance for some civil applications (such as rescue operations), a more realistic deployment involves the careful planning and placement of sensors. Even then, nodes may not be placed optimally to ensure that the network is fully connected and high-quality data pertaining to the phenomena being monitored can be extracted from the network. This work aims to address the problem of random deployment through two complementary approaches: The first approach aims to address the problem of random deployment from a communication perspective. It begins by establishing a comprehensive mathematical model to quantify the energy cost of various concerns of a fully operational wireless sensor network. Based on the analytic model, an energy-efficient topology control protocol is developed. The protocol sets eligibility metric to establish and maintain a multi-hop communication path and to ensure that all nodes exhaust their energy in a uniform manner. The second approach focuses on addressing the problem of imperfect sensing from a signal processing perspective. It investigates the impact of deployment errors (calibration, placement, and orientation errors) on the quality of the sensed data and attempts to identify robust and error-agnostic features. If random placement is unavoidable and dense deployment cannot be supported, robust and error-agnostic features enable one to recognize interesting events from erroneous or imperfect data