166 research outputs found
The solidification under zero gravity conditions of binary alloys exhibiting solid state immiscibility
The solidification behavior of gold-silicon alloys containing up to 25 at. % silicon was studied, and a mathematical model of gravity segregation during solidification was developed. A background of knowledge is provided which can be used in the design of zero gravity solidification experiments to be carried out in the 300-ft drop tower, in Aerobee rockets and in future space missions. Such experiments are needed to develop the basic scientific knowledge required for the design of economically viable space manufacturing processes. Some preliminary zero gravity experiments were carried out on a gold-25 at. % silicon alloy using the drop tower facility
Recommended from our members
Double-shell tank remaining useful life estimates
The existing 28 double-shell tanks (DSTS) at Hanford are currently planned to continue operation through the year 2028 when disposal schedules show removal of waste. This schedule will place the DSTs in a service life window of 4O to 60 years depending on tank construction date and actual retirement date. This paper examines corrosion- related life-limiting conditions of DSTs and reports the results of remaining useful life models developed for estimating remaining tank life. Three models based on controllable parameters such as temperature, chemistry, and relative humidity are presented for estimates to the year in which a particular DST may receive a breach in the primary tank due to pitting in the liquid or vapor region. Pitting is believed to be the life-limiting condition for DSTs,however, the region of the most aggressive pitting (vapor space or liquid) requires further investigation. The results of the models presented suggest none of the existing DSTs should fail by through-wall pitting until well beyond scheduled retrieval in 2028. The estimates of tank breach years (the year in which a tank may be expected to breach the primary tank wall) range from 2056 for pitting corrosion in the liquid region of tank 104-AW to beyond the next millennium for several tanks in the vapor region
Recommended from our members
DST pitting annual report
This report provides details of activities during FY 1996 for the double-shell tank pitting kinetics testing task
Project Management Concepts
This chapter covers fundamentals of project management. It introduces project management concepts and provides a system view of project management plan and processes with which they are implemented. The knowledge areas include scope, time, cost, quality, and risk. The chapter will also emphasize on the interrelated nature of these knowledge areas. In addition to introducing these knowledge areas, the chapter will attempt to develop an understanding of these concepts and the important role of project teams in managing projects successfully. This chapter will also discuss similarities and differences between the plan-driven and change-driven (Agile) project methods
Managing Quality in Aviation Projects
From aircraft manufacturing, product customization, aircraft maintenance, and aircraft launch and recovery, project management is threaded through all aspects of aviation. Given the supreme importance of quality to every aircraft manufacturer, airline, and passenger, it would be expected that quality management, within the context of project management, would be a construct that is clearly defined. The aim of this mixed-methods research seeks to understand how quality is managed and assured in aviation projects, whether or not the current quality management framework is applicable to the aviation industry, and how quality should ultimately be managed in aviation projects. The results of this study suggest that aviation project management could benefit by adopting a new lens for managing project quality and avoid a surface-level adoption of quality tools designed primarily for the mass production context
Recommended from our members
CHARACTERIZATION OF CORROSION PROBE COUPONS EXPOSED IN TANK 241-AN-107
C-Ring and Pin electrodes from Corrosion Probe retrieved from Tank 241-AN-107 were examined visually and by weight loss measurements. The weight loss measurements were carried out according to ASTM Method G-190. Corrosion rates estimated from the weight loss measurements indicated extremely limited corrosion with no visually observable pitting or cracking. The extremely low corrosion rates are in agreement with the results of ultrasonic examination of the primary tank wall
Recommended from our members
TANK 241-AN-107 CORROSION COUPON LABORATORY ANALYSIS
To support the corrosion study for Tank 241-AN-107, corrosion coupons consisting of C-rings and pins were removed from four detectors of the corrosion probe retrieved from the tank. The detectors were located as follows: one in the sludge layer, one in the liquid layer, one in the lower head space and the last in the upper head space. ASTM Method G-190 was used to determine the amount of corrosion product present
Recommended from our members
Corrosion of low-carbon steel under environmental conditions at Hanford: Two-year soil corrosion test results
At the Hanford Site, located in southeastern Washington state, nuclear production reactors were operated from 1944 to 1970. The handling and processing of radioactive nuclear fuels produced a large volume of low-level nuclear wastes, chemical wastes, and a combination of the two (mixed wastes). These materials have historically been packaged in US Department of Transportation (DOT) approved drums made from low-carbon steel, then handled in one of three ways: (A) Before 1970, the drums were buried in the dry desert soil. It was assumed that chemical and radionuclide mobility would be low and that the isolated, government-owned site would provide sufficient protection for employees and the public. (B) After 1970, the drums containing long-lived transuranic radionuclides were protected from premature failure by stacking them in an ordered array on an asphalt concrete pad in the bottom of a burial trench. The array was then covered with a large, 0.28-mm- (011-in.-) thick polyethylene tarp and the trench was backfilled with 1.3 m (4 ft) of soil cover. This burial method is referred to as soil-shielded burial . Other configurations were also employed but the soil-shielded burial method contains most of the transuranic drums. (C) Since 1987, US Department of Energy sites have complied with the Resource Conservation and Recovery Act of 1976 (RCRA) regulations. These regulations require mixed waste drums to be stored in RCRA compliant large metal sheds with provisions for monitoring. These sheds are provided with forced ventilation but are not heated or cooled
Project Management: A Natural Career Destination for Military Veterans
This quantitative study surveys 595 United States military veterans from all four branches of the military in order to ascertain the degree to which the branches of the military prepare individuals for possible future careers in civilian project management roles. Further, the study compares the relative knowledge of project management technical skill areas, processes and personal competencies. Although all branches provided responses indicating a high degree of familiarity with and preparation for project management roles, some significant differences were observed in responses between military branches
Insights From the Field: Project Execution Success and Failure
Project execution plays a decisive role in project success, but past research did not focus on the project manager’s perspective of what needs to be accomplished to achieve success. In this study, the authors used qualitative techniques to look for reoccurring themes related to 44project managers’ responses to interview questions associated with successful project execution and failed project execution. The study found that despite the project management profession growth, professional associations’ efforts, and their professional development endeavors, project management execution seems to be concerned with what has happened versus what is happening in a project. This study provides a conceptual framework for project execution success strategies that have implications for project management training and mentoring
- …
