Design and development of a water vapor electrolysis unit

Design and development of water vapor electrolysis unit for oxygen productio

Titanium alloy stress corrosion cracking in presence of dinitrogen tetroxide

Study resulting in a satisfactory stress corrosion cracking test with extremely consistent results produced six new analytical methods. Methods detect and determine differences in the minor constituent composition of different types of dinitrogen tetroxide

Dielectric-Recovery Characteristic of Power Arcs in Large Air Gaps

A satisfactory test technique has been developed for studying the rates of dielectric recovery of large air gaps and other types of power-system insulation. This permits the accurate control of the fault conditions so that all practical types of fault currents can be studied. These are: (1) very high magnitude short-duration surges typical of lightning currents; (2) currents of power-system frequencies; and (3) intermediate duration currents such as those which might result from high-frequency current zeros produced by natural system oscillations. Results are presented showing the rate of dielectric recovery of 3-, 6-, and 11-inch standard rod gaps for power frequency fault currents up to 700 amperes. Electrode cooling effects were found important at 3-inch gap spacings but not at six inches or above. The 11-inch gap data are proportionately higher than the 6-inch data indicating that the results can be extrapolated. The data show that for arcs of a few cycles actual duration has little effect on rate of recovery. A range of current magnitudes from 50 to 700 amperes causes only about a 2-to-1 variation in rate of recovery. For the normal ratios of transmission-line insulation level to operating voltage (about four to one) minimum delay times of from 0.025 second for 100-ampere faults to 0.05 second for 700 ampere faults are required before the recovery voltage reaches the magnitude of the normal applied voltage. Time intervals of 0.05 to 0

The Importance of Pulsed Physical Events for Sustainability of Louisiana Coastal Forested Wetlands

A number of freshwater diversions from the Mississippi River into Louisiana’s coastal wetlands are currently in operation or in the planning stage. These diversions have multiple objectives including maintaining a desirable salinity gradient, restoring deteriorating wetlands, and enhancing fisheries. The extensive freshwater forested wetlands surrounding the western end of Lake Pontchartrain receive little or no sediment input and are currently deteriorating due to continuous flooding. Diverting nutrient-rich water through wetlands can lead to substantial nutrient removal and to enhanced accretion. The objective of this paper is to compare the impacts on freshwater wetland ecology, accretion, and water quality of several scenarios for diverting freshwater from the Mississippi River. Accretion will be increased so that the area will become progressively less flooded, enhancing productivity and seedling recruitment. With overland flow, about 73% of N and 48% of P will be retained in the wetland, while other alternatives are estimated to remove 0-33% of N and 0-40% of P. Productivity of the forested wetland will decrease by at least 20-50% over the next 50 years if nothing is done, but there would be a substantial increase in productivity if river water is diverted into the area. We recommend that a 45-55 m3/s diversion be placed in the southern portion of the swamps of Lake Maurepas and that the diversion be operated annually from winter to early spring. There are indications that a diversion in late summer and fall would be beneficial, as that is when salt pulses typically occur

The learning experiences of health and social care paraprofessionals on a foundation degree

Foundation degrees have been developed in the UK as a means of meeting the learning needs of paraprofessionals in health and social care and the services within which they work in a cost-effective fashion. Workplace learning is an intrinsic component to these degrees. Taking a socio-cultural perspective, this paper examines how the students' workplaces, life circumstances and sense of career trajectory shaped their learning experience and motivation. A small-scale evaluation study, using semi-structured interviews, focused on the learning experiences of a group of paraprofessionals enrolled in a foundation degree in health and social care. Data revealed fragmented employment patterns, underpinned by consistent vocational drives. While the study resonated with vocation, participants were ambivalent or lacked information about career progression. Workplace conditions, relationships and limited time shaped learning and coping strategies. A strategic and focused approach to student learning is required and includes attention to career pathways, workforce development strategy, the requirements of a range of stakeholders, workplace supervision and support for learning