Intergenerational Bargains: Negotiating our debts to the past and our obligations to the future

The question of intergenerational obligation can be framed in multiple ways. Here, we use the idea of bargains to think about how those of us in the present relate to both the past and the future. To understand this approach assumptions behind the idea of intergenerational bargains are posited, three potential ontologies for intergenerational thinking are explored, and principles that might be applied to intergenerational obligations are considered. Finally, an ethic for intergenerational obligation is proposed. The idea of intergenerational bargains reveals common frameworks among futures studies, ecological economics, and sustainability science

TB101: The Relevance of Option Value in Benefit-Cost Analysis

This publication represents a review and a critical re-evaluation of the literature dealing with option value. This literature is rich and dynamic and provides a fascinating sequence of articles, comments, and rebuttals. Reevaluation of the concept requires a rather comprehensive review of this literature, which is something that has not been provided to date. The literature review is also important because the work of some authors has been systematically overlooked in the course of the debate. As a result of this oversight, the original formulation of the concept continues to be cited in the literature even though its practical significance is doubtful.https://digitalcommons.library.umaine.edu/aes_techbulletin/1085/thumbnail.jp

B793: Estimation of the Cost of Providing Publicly-Supported Outdoor Recreational Facilities in Maine

Federal, state and local government agencies have historically played a significant role in providing outdoor recreational facilities for public use. Public agencies provide campgrounds, picnic areas, hiking trails, access to swimming and boating sites, interpretive facilities and programs, and numerous other types of recreational facilities. Until recently, very little attention was devoted to the costs associated with the provision of these facilities. Public funds were allocated to the construction and operation of the facilities without much concern for the economic consequences of these actions. However, during the last decade several studies have documented the cost of providing publicly supplied outdoor recreational facilities and some of the consequences. These studies have analyzed a wide range of facilities managed by state and federal agencies. The objective of this project is to measure the cost of providing various outdoor recreational facilities in Maine. The project was initiated in the Spring of 1981 following a meeting of personnel from several of the public agencies that provide recreational services and facilities. Several concerns were voiced at that meeting, including the need to revise user fees, uncertainty regarding the level of future agency funding, lack of information about provision costs, the need to document provision costs for legislative bodies, and questions regarding whether users should pay a larger share of the costs of providing the recreational facilities. A cost of provision study of a wide range of public recreational facilities seemed to be a first step in addressing many of these concerns. A cooperative agreement was written in which the Department of Agricultural and Resource Economics at the University of Maine at Orono would perform the study with funding provided by the U.S. Forest Service. Agencies participating in the study include the Maine Bureau of Parks and Recreation, Baxter State Park, Evans Notch Ranger District of the White Mountains National Forest, and Acadia National Park. The actual facilities included in the study are shown in Figure 1.https://digitalcommons.library.umaine.edu/aes_bulletin/1124/thumbnail.jp

Two birds, one stone: Can a natural resources core class serve the entire university?

As natural resource management grows more complex, natural resource curricula continually must expand to incorporate new topics and techniques. At the same time, colleges and departments are pressured to keep within tight budgets, and to meet the demands of students, parents and legislators to minimize the length of time needed to acquire a degree. In the College of Natural Resources (CNR) at Utah State University (USU), one strategy for achieving these apparently conflicting needs has been to create core courses that can serve students in all CNR majors, thereby reducing the potential for overlap and redundancy. When the university switched in 1998 from a quarter to a semester calendar, the college was challenged to maintain a core while reducing the number of required credits, continuing to meet professional accreditation standards, and participating in an expanded university-wide general education program. One way we tried to meet that challenge was to develop a new core course called Natural Resources and Society that would simultaneously: (1) meet the core goal of introducing majors to the human dimensions of natural resources; (2) meet the general education goal of providing a broad introduction to the ideas and methods of the social sciences; (3) attract large numbers of non-CNR students (important because some university funding is tied to student credit hours); and (4) recruit students into the university\u27s lowest-enrollment college. This paper describes our evaluation of the course\u27s success at meeting those objectives

An alternate method for achieving temperature control in the -130 C to 75 C range

Thermal vacuum testing often requires temperature control of chamber shrouds and heat exchangers within the -130 C to 75 C range. There are two conventional methods which are normally employed to achieve control through this intermediate temperature range: (1) single-pass flow where control is achieved by alternately pulsing hot gaseous nitrogen (GN2) and cold LN2 into the feed line to yield the setpoint temperature; and (2) closed-loop circulation where control is achieved by either electrically heating or LN2 cooling the circulating GN2 to yield the setpoint temperature. A third method, using a mass flow ratio controller along with modulating control valves on GN2 and LN2 lines, provides excellent control but equipment for this method is expensive and cost-prohibitive for all but long-term continuous processes. The single-pass method provides marginal control and can result in unexpected overcooling of the test article from even a short pulse of LN2. The closed-loop circulation method provides excellent control but requires an expensive blower capable of operating at elevated pressures and cryogenic temperatures. Where precise control is needed (plus or minus 2 C), single-pass flow systems typically have not provided the precision required, primarily because of overcooling temperature excursions. Where several individual circuits are to be controlled at different temperatures, the use of expensive cryogenic blowers for each circuit is also cost-prohibitive, especially for short duration of one-of-a-kind tests. At JPL, a variant of the single-pass method was developed that was shown to provide precise temperature control in the -130 C to 75 C range while exhibiting minimal setpoint overshoot during temperature transitions. This alternate method uses a commercially available temperature controller along with a GN2/LN2 mixer to dampen the amplitude of cold temperature spikes caused by LN2 pulsing. The design of the GN2/LN2 mixer, the overall control system configuration, the operational procedure, and the prototype system test results are described

Our Environment: A Glimpse at What Mainers Value

Understanding environmental worldviews is impor­tant because values can play a strong part in defining and resolving policy debates. Mark Anderson, Caroline Noblet and Mario Teisl present analysis of a survey that included questions about Mainers’ environmental values. They note that people can value the environment in multiple ways at the same time, and that these values are not necessarily mutually exclusive. In the end, they say, “values matter” in environmental policy

A new approach for performing contamination control bakeouts in JPL thermal vacuum test chambers

Contamination control requirements for the Wide Field/Planetary Camera II (WF/PC II) are necessarily stringent to protect against post-launch contamination of the sensitive optical surfaces, particularly the cold charge coupled device (CCD) imaging surfaces. Typically, thermal vacuum test chambers have employed a liquid nitrogen (LN2) cold trap to collect outgassed contaminants. This approach has the disadvantage of risking recontamination of the test article from shroud offgassing during post-test warmup of the chamber or from any shroud warming of even a few degrees during the bakeout process. By using an enclave, essentially a chamber within a chamber, configured concentrically and internally within an LN2 shroud, a method was developed, based on a design concept by Taylor, for preventing recontamination of test articles during bakeouts and subsequent post-test warmup of the vacuum chamber. Enclaves for testing WF/PC II components were designed and fabricated, then installed in three of JPL's Environmental Test Lab chambers. The design concepts, operating procedures, and test results of this development are discussed

Evaluation of a Full-Depth Asphaltic Concrete Pavement

This study was initiated to verify a newly-developed set of design curves for full-depth asphaltic concrete pavements. Quality control during construction was checked using nuclear density testers, Benkelman beams, and a Road Rater. During the course of this study, an analysis system (predicated upon the elastic theory model) was developed to interpret the dynamic deflections as measured by the Road Rater. The thickness design curves were verified by elastic theory and deflection testing within the accuracy of construction variations. Measured rut depths were analyzed in terms of potential rut depth resulting from consolidation under traffic due to lack of obtaining 100-percent of Marshall density during compaction. Traffic was monitored using automatic traffic counters, manual classification/volume counts, and weigh-in-motion scales installed in the pavement

Breaking and Seating of Rigid Pavements

Breaking and seating has been utilized extensively in Kentucky to rehabilitate portland cement concrete pavements. Experience over three or four years with this type of design and construction are summarized and reported. Breaking to a range of nominal fragments is evaluated. Evaluation of two roller weights for seating is reported. The use of dynamic deflections to evaluate the effectiveness of the breaking and seating process and to measure the appropriateness of the asphaltic concrete overlay