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Articles 179611 - 179640 of 197988

Full-Text Articles in Engineering

Challenges To United States Tactical Air Force Aircraft Maintenance Personnel: Past, Present And Future, Barbara L. Harris Sep 1991

Challenges To United States Tactical Air Force Aircraft Maintenance Personnel: Past, Present And Future, Barbara L. Harris

Theses and Dissertations

This study assessed the challenges Tactical Air Force (TAF) aircraft maintenance personnel face as a result of the TAF reorganization. The goal was to provide aircraft maintenance managers a basis for evaluating and meeting those challenges. To accomplish this, emphasis was placed on documenting the concepts, events, and conditions which led to changes in military aircraft maintenance from the birth of aviation to the present. Current issues such as the proposed move to two-level maintenance and the formation of the TAF composite and Objective Wings were also addressed. Research was conducted through the review of available historical documents, complemented by …


An Evaluation Of The Implementation Of Two-Levels Of Maintenance At Strategic Air Command Intercontinental Ballistic Missile Bases, Alan H. Russell Sep 1991

An Evaluation Of The Implementation Of Two-Levels Of Maintenance At Strategic Air Command Intercontinental Ballistic Missile Bases, Alan H. Russell

Theses and Dissertations

As a result of the 1979 Defense Management Review, Headquarters, Strategic Air Command has initiated programs of alternative levels of maintenance in order to trim excess costs. This study investigates the suitability of the SAC program which changed selected base-level strategic missile maintenance tasks from three to two-levels of maintenance. Using an opinion oriented questionnaire, this research surveyed a sample of missile maintenance personnel on their perceptions of the SAC program which implemented an alternative to intermediate-level maintenance. Analysis of survey results show respondents tended to believe the SAC program has not added benefit to their mission effectiveness. Other studies …


Desert Express: An Analysis On Improved Customer Service, Thomas C. Thalheim Sep 1991

Desert Express: An Analysis On Improved Customer Service, Thomas C. Thalheim

Theses and Dissertations

Operation Desert Shield/Storm provided an opportunity to test the planning for U.S. forces to operate in a low intensity conflict. Both operations provided the opportunity for the logistics community to observe how the support forces provided the required supplies to the forward combat forces. In response to customers' requests, the U.S. Transportation Command created Desert Express, a daily package express flight from Charleston, SC to Saudi Arabia. The research question addresses the how and why Desert Express came about. Additional investigative questions cover the following: mission objectives, planners' and customers' expectations, system performance, and implications on the Defense Transportation System. …


Development Of An Operationally-Oriented Measure Of Sustainability, Moira D. Williams Sep 1991

Development Of An Operationally-Oriented Measure Of Sustainability, Moira D. Williams

Theses and Dissertations

This thesis proposes a framework for evaluating sustainability in the Air Force and for determining an appropriate measure of effectiveness that is both meaningful in a military sense and useful in planning and programming decisions. Following a literature review of organizational performance measures and strategy formulation, Michael Porter's Competitive Analysis model for strategy selection was presented. This model was then used to evaluate case studies in which organizations faced strategic decisions and to suggest measures by which these organizations could determine their effectiveness. The model was then shown to be applicable to the Air Force, and recommendations on implementing such …


Life Cycle Costs Of The C-130 Electrical Power System Upgrade, Theodore D. Seymour Sep 1991

Life Cycle Costs Of The C-130 Electrical Power System Upgrade, Theodore D. Seymour

Theses and Dissertations

This research investigated the life cycle costs of three alternative electrical power systems for a planned electrical system upgrade to the C-130 transport aircraft. Research identified the contractors as (1) Sundstrand, (2) Westinghouse, and (3) Leland. The literature review included discussions on the C-130, electrical power systems and the proposed alternatives, and the elements of life cycle cost analysis. In the discussion on supportability issues, this research evaluated changes in mission capable rates and the needed fleet size to perform the current mission. In estimating Operating and Support costs, this research used the analogy approach. Analogies were based on expert …


Industrial Wastewater Management Practices In Air Force Logistics Command, Patrick J. Smith Sep 1991

Industrial Wastewater Management Practices In Air Force Logistics Command, Patrick J. Smith

Theses and Dissertations

The selection of a model plant was based upon criteria established by a review of current literature. The criteria were permit compliance, plant performance, and the adoption of pollution prevention as a corporate environmental philosophy. In this study, private sector firms were examined to identify the best industrial wastewater management practices using a Total Quality Management (TQM) tool called benchmarking. The data gathering process consisted a survey of water pollution control organizations, and a survey of benchmark candidates. The purpose of surveying water pollution control organizations was to objectively identify possible benchmark candidates. A questionnaire was then used to gather …


An Analysis Of Base Level Environmental Organizations, John F. Akers Jr. Sep 1991

An Analysis Of Base Level Environmental Organizations, John F. Akers Jr.

Theses and Dissertations

The purpose of this thesis was to try and determine if there was one type of environmental organization which was truly so much more effective than the others that all bases should have it, or if the decision of which type of environmental organization to have should be left entirely to the bases. In addition, I hoped to discover the advantages and disadvantages of each type of organizational structure. I feel that knowing these advantages and disadvantages will greatly aid those individuals making the decisions on environmental organizational structure. In completing this study I turned to the only place the …


Impacts Of Biomonitoring Requirements On Dod Wastewater Treatment Facilities, James R. Brady Sep 1991

Impacts Of Biomonitoring Requirements On Dod Wastewater Treatment Facilities, James R. Brady

Theses and Dissertations

Legislative emphasis on reducing the toxicity of wastewater effluent has resulted in increasingly sophisticated methods of determining toxicity. The purpose of this research project is to assess the impacts on DoD wastewater treatment facilities of one new monitoring method, biomonitoring. Biomonitoring has impacted DoD wastewater treatment facilities, however not to the degree anticipated. For bases that have been impacted, cost of contracting the tests is the primary problem associated with biomonitoring. Many bases have not been impacted because wastewater reuse has negated the need for discharge permits, and the inherent monitoring requirements. Bases subject to biomonitoring should assess water reuse …


A Comparative Analysis Of Three Water Treatment Programs For Cooling Tower Systems, Jeffry W. Shea Sep 1991

A Comparative Analysis Of Three Water Treatment Programs For Cooling Tower Systems, Jeffry W. Shea

Theses and Dissertations

This study investigated the cost and effectiveness of three cooling tower water treatment programs. The programs studied were an acid program developed at WPAFB, a commercial solubilizer program manufactured by Lombardi, Inc, and a crystal modifier program developed by Dias, Inc. The experiment ran for 60 days at which time cost and effectiveness data were collected. Cost comparison was evaluated on the basis of tower performance in MBtu. The costs considered in this experiment were water costs, sewer costs, and chemical costs. All costs were recorded and totaled, then divided by the tower's performance. The effectiveness of each treatment method …


Evaluation Of Managerial Challenges Created By Acceleration Of The Installation Restoration Program, Robert L. Vinson Iii Sep 1991

Evaluation Of Managerial Challenges Created By Acceleration Of The Installation Restoration Program, Robert L. Vinson Iii

Theses and Dissertations

This study investigates the distribution of managerial tasks related to the Installation Restoration Program (IRP). Initiated in 1986, the IRP is the DoD program to identify and clean-up hazardous waste sites. Study areas include current distribution of managerial tasks, changes in task distribution needed to accelerate the program, and potential resource constraints. Additionally, the study considers how acceleration of Army and Navy restoration programs could impact the Air Force IRP. The study reveals IRP management is heavily centralized at MAJCOM with most technical work being performed through contracts with service centers. Individual bases have little direct involvement in the program. …


The Operation Of Military Family Housing As A Business Enterprise. A Case Study At Langley Air Force Base, Virginia, Michael T. Ray Sep 1991

The Operation Of Military Family Housing As A Business Enterprise. A Case Study At Langley Air Force Base, Virginia, Michael T. Ray

Theses and Dissertations

The focus of this research was to determine the feasibility of operating Military Family Housing (MFH) as a business enterprise, based on rental income. A case study of the Langley AFB Military Family Housing operation during FY 90 was used to determine if housing allowances forfeited by residents of base housing would provide sufficient rental income for the annual operations, maintenance and capital improvement of the MFH assets. It further compared the descriptive data from Langley AFB, Virginia, to USAF averages to determine if the findings at Langley were generalizable across the Air Force. The case study showed that Basic …


An Expert System Solution For The Quantitative Condition Assessment Of Electrical Distribution Systems In The United States Air Force, David O. Paine Sep 1991

An Expert System Solution For The Quantitative Condition Assessment Of Electrical Distribution Systems In The United States Air Force, David O. Paine

Theses and Dissertations

Faced with a rapidly decreasing budget, the Air Force is in need of a method to objectively evaluate its aging utility infrastructure assets. This objective evaluation could be used to compare similar facility infrastructure systems for identification of possible problem areas and prioritization of major repair projects. This thesis developed a component model which can be used to objectively evaluate a typical electrical distribution system. The Delphi process was used to gather expert opinions regarding three areas: (1) the critical components which should be included in the model, (2) the relative importance of each selected critical component, and (3) the …


Higher-Order Thickness Expansions For Cylindrical Shells, Randy A. Smith Sep 1991

Higher-Order Thickness Expansions For Cylindrical Shells, Randy A. Smith

Theses and Dissertations

Eight variations of higher-order transverse shear deformation (HTSD) theory were developed for composite shells. Three attributes were varied to produce the eight variations. These attributes include the order of the thickness expansions used to approximate the shell shape factors and the assumed linear displacement field and the nonlinearity of transverse shear strain. Several cylindrical shell problems were investigated using SHELL, a finite- element code with a 36 degree of freedom cylindrical shell element. MACSYMA, a symbolic manipulation code, was used to formulate the element independent stiffness arrays for each variation of the theory. When all nonlinear strain- displacement terms for …


Analysis Of Traffic Accident Data In Kentucky (1986-1990), Kenneth R. Agent, Jerry G. Pigman Sep 1991

Analysis Of Traffic Accident Data In Kentucky (1986-1990), Kenneth R. Agent, Jerry G. Pigman

Kentucky Transportation Center Research Report

This report includes an analysis of traffic accident data in Kentucky for the years of 1986-1990. A primary objective of this study was to determine average accident statistics for Kentucky highways. Average and critical number and rates of accidents were calculated for various types of highways in rural and urban areas. These data can be used in Kentucky's procedure to identify locations that have abnormal rates or numbers of accidents.

Another objective of this study was to provide data which can be used in the preparation of the problem identification portion of Kentucky's Annual Highway Safety Plan. County and city …


Investigation Of Advanced Aircraft Performance Measures Of Merit Including New Agility Metrics, Bruce A. Fox Sep 1991

Investigation Of Advanced Aircraft Performance Measures Of Merit Including New Agility Metrics, Bruce A. Fox

Theses and Dissertations

Advanced aircraft performance measures of merit have been proposed and individually analyzed by various researchers. These metrics have been consolidated into a single computer code as part of this research effort. This code was used to study the relationships between the advanced metrics, aircraft design metrics and an aircraft's trajectory performance. The study found a linear relationship existed between the advanced metrics and the design metrics. This relationship was used to quantify the required levels of the advanced metrics which would give desired changes in trajectory performance. The results showed that advanced metrics could be applied only to very specific …


Model Identification And Control System Design For The Lambda Unmanned Research Vehicle, Gerald A. Swift Sep 1991

Model Identification And Control System Design For The Lambda Unmanned Research Vehicle, Gerald A. Swift

Theses and Dissertations

Research for this thesis centered on the Lambda Unmanned Research Vehicle (URV), an asset of the Flight Dynamics Directorate, Wright Laboratory Patterson AFB. The following tasks were accomplished: (1) a linear, state-space, small perturbation model was developed for both the longitudinal and lateral directional dynamics of the vehicles, and (2) pitch rate roll rate, and yaw rate flight controllers were designed using classical and multivariable feedback methods. The parameters of the linear, state space, small perturbation model were estimated from actual flight test data. Digital Datcom was first used to estimate stability and control derivatives from the vehicle's geometry. Maximum …


Analysis Of Transport Phenomena In The Coating Of Fibers By Cvd, J H. Scholtz, J E. Gatica, Hendrik J. Viljoen Sep 1991

Analysis Of Transport Phenomena In The Coating Of Fibers By Cvd, J H. Scholtz, J E. Gatica, Hendrik J. Viljoen

Papers in Materials Science

Inorganic coated fibres produced by chemical vapour deposition find several technological applications. In this CVD process, a filler core is mounted in a reactor between two electrodes. Reactive gases flow over the substrate and react near or on the fibre surface to form the desired coating. Experience has showed that, quality deposition can only be obtained over a small range of the governing parameters: these parameters are, however, difficult to control. In the present, study a mathematical model is developed for the reactor configuration under consideration. The different mass and energy transport mechanisms are compared and their influence on the …


Evaluation Of Stamark Brand Bisymmetric 1.75 Grade Pavement Marking Tape, Kenneth R. Agent Sep 1991

Evaluation Of Stamark Brand Bisymmetric 1.75 Grade Pavement Marking Tape, Kenneth R. Agent

Kentucky Transportation Center Research Report

The objective of this project was to evaluate the performance of Stamark Brand Bisymmetric 1.75 Grade pavement Marking Tape (Series 320) on a large-scale installation on Interstate 24 in McCracken County. The evaluation consisted of periodic inspection of the tape to determine its durability, appearance, and reflectivity.

The tape has demonstrated good performance after two years in service. No durability problems were noted. While the appearance of the tape was not as bright as a typical traffic paint, it was adequate. The tape has maintained a high level of reflectivity. The performance of the material would potentially warrant additional use …


Bs News Sep 1991

Bs News

Building Services Engineering

No abstract provided.


Design Of Automotive Structural Components Using High Strength Sheet Steels Structural Strength Of Cold-Formed Steel Beams Under Dynamic Loads, Chi-Ling Pan, Wei-Wen Yu Sep 1991

Design Of Automotive Structural Components Using High Strength Sheet Steels Structural Strength Of Cold-Formed Steel Beams Under Dynamic Loads, Chi-Ling Pan, Wei-Wen Yu

CCFSS Library (1939 - present)

INTRODUCTION It has long been recognized that material properties and stress-strain relationships of sheet steels can be influenced by the strain rate. A considerable amount of theoretical and experimental research have been undertaken in the past to study material properties and the behavior of structures under dynamic loads and impact loads. In view of the fact that in the current AISI Automotive Steel Design Manual 1, the design criteria for effective design width are based on the test results under static loading condition, the objective of this investigation was to study the validity of these effective design width formulas for …


A Comparison Of The Air Force, Army, And Navy Test And Evaluation Reliability And Maintainability Data Base Systems, Donald L. Scantlan Jr. Sep 1991

A Comparison Of The Air Force, Army, And Navy Test And Evaluation Reliability And Maintainability Data Base Systems, Donald L. Scantlan Jr.

Theses and Dissertations

This study was conducted to create a single source document which could be used by test and evaluation personnel involved in joint programs for translating reliability and maintainability terms. The comparison begins by describing the forms, data elements, and data items, as collected by the Air Force's System Effectiveness Data System, the Army's Reliability, Availability, Maintainability Logistics System, and the Navy's Maintenance and Material Management, Maintenance Data System. The Findings paragraph is a stand-alone document which could serve as a translating dictionary for reliability and maintainability data elements between the different service's data systems. Upon the conclusion of this study, …


Determining Production Capability In Aircraft Maintenance: A Regression Analysis, Charles R. Jung Sep 1991

Determining Production Capability In Aircraft Maintenance: A Regression Analysis, Charles R. Jung

Theses and Dissertations

This research analyzed twenty-three maintenance constraint and three production output performance measures for nine SAC aircraft systems. SAS System for Elementary Statistical Analysis is used to analyze twenty-one months of ex post facto maintenance data. Correlation analysis is used to identify maintenance constraints that assist in explaining aircraft maintenance production capability. Forward stepwise regression is used to build predictive models of maintenance production capability for each of the nine aircraft systems. The twenty-three maintenance constraint measures are regressed against three productivity output measures: Mission Capable Rate, Total Not Mission Capable Supply Rate and Total Not Mission Capable Maintenance Rate. The …


Applying The Theory Of Constraints To A Base Civil Engineering Operations Branch, Bryan K. Zachmeier Sep 1991

Applying The Theory Of Constraints To A Base Civil Engineering Operations Branch, Bryan K. Zachmeier

Theses and Dissertations

The purpose of this thesis is to introduce the Civil Engineering manager to the Theory of Constraints management philosophy and to show how to apply this process of ongoing improvement to the Operations Branch. One of the reasons for the success of Theory of Constraints in commercial firms is that it provides all levels of management the ability to find simple solutions for bridging the gap between local and global issues. This 'bridge' is built by clearly defining the goal of the organization and using performance measurements capable of predicting the effect of local decisions and actions on the goal. …


Crystallization Kinetics And Polyblends Of Poly(Ethylene Terephthalate) Recycled From Post-Consumer Beverage Bottles, Peming Peter Hsu Aug 1991

Crystallization Kinetics And Polyblends Of Poly(Ethylene Terephthalate) Recycled From Post-Consumer Beverage Bottles, Peming Peter Hsu

Dissertations

In order to reduce waste generation, and comply with state and federal laws, plastic beverage bottles are usually undergoing recycling. Poly(ethylene terephthalate) [PET], which is the main component the bottles are made of, cannot be used for manufacturing new food containers, and has to be used for manufacturing other end consumer products. The recycled PET is a cheap material, but its use is problematic due to the low crystallization rates of PET. The present study investigates ways of accelerating PET crystallization by using inorganic carbonate salts as nucleating agents. This study also explores the possibility of forming polymer blends based …


Nontraditional Machining Techniques With Emphasis On Waterjet Milling, Shiv K. Kunapuli Aug 1991

Nontraditional Machining Techniques With Emphasis On Waterjet Milling, Shiv K. Kunapuli

Theses

The rapid growth of harder and difficult-to-machine materials over the past two decades necessitates the development of compatible nonconventional machining techniques, as detailed in this work, with special emphasis on one of the most recent machining method, the abrasive-waterjet technique(AWJ).

The feasibility of using AWJ for milling on glass is investigated. Due to the large number of parameters involved in the AWJ technique, and the multitude of machining requirements, optimization of performance is the focus. These parameters include waterjet pressure, particle size, abrasive flow rate, traverse rate and number of passes.

Surface topography is found to be a function of …


Performance Of The Extended Token Bus Network With Asymmetric Load Distribution, Hong Lin Aug 1991

Performance Of The Extended Token Bus Network With Asymmetric Load Distribution, Hong Lin

Theses

The Token Bus, IEEE 802.4, provides high priority message options. The delay of high priority messages becomes an important criterion in the design and management of computer communication networks. A goal of the protocol is to allocate sufficient bandwidth and frequency of access to minimize of the high priority message delay. In this study, a simulation model of a priority based network, consisting of two token bus networks interconnected by a bridge is implemented. The load distribution among stations is asymmetric and the messages are divided into two priorities, high and low. Both fixed and variable token token holding times …


Implementation Of An Integrated High Energy Beam Workcell, Varadaraj Souda Aug 1991

Implementation Of An Integrated High Energy Beam Workcell, Varadaraj Souda

Theses

This study is an effort to advance the technology of machining by High energy beams. Investigation of the Waterjet, Plasma and the Oxyfuel beams was carried out to explore novel machining techniques. The study was focussed on three major objectives.

One of the major objectives was to set up an Integrated beam workcell consisting of the three beams. A hydroabrasive waterjet workcell was modified to install the three cutting tools to be along the same line of traverse. An integrated beam consisting of the thermal and the waterjet beams was produced because of this arrangement. The feasibility of using the …


A Biomechanical Analysis Of Three Humeral Fracture Fixation Systems, Alina Michelle Waite Aug 1991

A Biomechanical Analysis Of Three Humeral Fracture Fixation Systems, Alina Michelle Waite

Theses

Often, humeral fractures requiring internal fixation can be a challenging orthopaedic procedure. Each method of treatment possesses clinical and biomechanical advantages and disadvantages. Rigid plate fixation is highly successful in treating a large variety of long bone fractures. Nevertheless, excessive soft tissue dissection is necessary, and vascular and neural anatomy of the humerus can make plate application and removal difficult. An intramedullary nail offers a relatively simple procedure, thereby reducing these anatomical concerns. However, rotational instability at the fracture site is a common complication with a conventional intramedullary nail. Thus, a study was conducted to evaluate a new interlocking intramedullary …


An Approach To Improving The Antithrombogenesis Of Pneumatic Diaphragm Artificial Ventricle : Fabrication And Design Considerations, Hui-Sun Wang Aug 1991

An Approach To Improving The Antithrombogenesis Of Pneumatic Diaphragm Artificial Ventricle : Fabrication And Design Considerations, Hui-Sun Wang

Theses

Thrombus formation is one of the major problems in artificial heart development and its clinical applications. In order to improve the antithrombogenesis in the artificial ventricles, three aspects of investigation have been done in the laboratory.

1] the surface features and the surface defects on specially prepared samples made of polyurethane and silicon rubber were studied and analyzed by scanning electron microscopy ( SEM ), light microscopy and KEVEX Feature Analysis for understanding and controlling the blood contacting surface.

2] the polyurethane blood contacting surface with smooth surface fabricated by solution cast process, the material treatment, and the fabrication procedure …


Graded Buried Channel Charge Coupled Device Design, Zengjing Wu Aug 1991

Graded Buried Channel Charge Coupled Device Design, Zengjing Wu

Theses

A process and device simulation study has been made to optimize a new type of buried channel CCD (BCCD) structure to be referred to as Graded BCCD (GBCCD) whose buried channel is formed by multiple implantations for achieving higher charge transfer efficiency. The 2-D process simulation tool SUPREM4 and 2-D device simulation tool PISCES2 were used in this research. The simulation results of the GBCCD with double channel implants are compared with the previously obtained experimental results.

Triple channel implants under the conditions of various process parameters were also simulated and the optimized case was chosen on the base of …