Dynamic Considerations for Control of Closed Life Support Systems

Reliability of closed life support systems depend on their ability to continue supplying the crew's needs during perturbations and equipment failures. The dynamic considerations interact with the basic static design through the sizing of storages, the specification of excess capacities in processors, and the choice of system initial state. A very simple system flow model was used to examine the possibilities for system failures even when there is sufficient storage to buffer the immediate effects of the perturbation. Two control schemes are shown which have different dynamic consequences in response to component failures

Educational Facility Space Guidelines for Seventh-Day Adventist Schools, K-12 in the United States

Problem. There is a lack of definitive educational facility space guidelines that Seventh-day Adventist church groups may follow in their planning for new school plants. Since re­ quests constantly arrive at the denomination\u27s headquarters for assistance in the planning of school facilities, the General Conference of Seventh-day Adventists through its Department of Education has requested that a set of guide­ lines relative to minimum space requirements be developed to cover grades K-12 in the United States. Therefore, the primary purpose of the study was to develop minimum space guidelines for the planning of school facilities for the United States portion of the North American Division of Seventh-day Adventists. Method. In order to provide a viable basis for the space guidelines, literature and research were reviewed, the requirements and standards of the fifty states relative to space guidelines were identified, recommendations from professional associations were sought, and personal con­ tacts were made. An analysis of the data gathered yielded information from which it was possible to identify those elements considered significant and upon this information was built a set of suggested minimum space guidelines. All of the superintendents of education in the United States portion of the North American Division of Seventh-day Adventists were asked to respond to the suggested guidelines through the use of an opinionnaire. The guidelines were also submitted to a selected panel of jurors. On the basis of the ideas and information gath­ ered, the minimum space guidelines were revised. The guidelines were then resubmitted to selected members of the panel of jurors for their final evaluation. Conclusions. Major conclusions drawn as a result of literature surveyed, information gathered, and experience gained during the course of the study were that: 1. It is possible to ascertain facility and space requirements by surveying literature and gathering data from the various states 2. The planning of school plants is a complica­ ted process which needs input from teachers, educational administrators, the community, and architects 3. Space guidelines are generally built upon opinions or committee actions and not upon research 4. The only solid research found (Stottlemyer, 1965; Gaude, 1965; Daniels, 1966; Rosenfeld, 1968) con­ cerning the relationship of achievement in subject matter to classroom space, role behavior of pupils to classroom space, number and kinds of pupil activities to classroom space, and pupil deviant behavior to classroom space is largely ignored 5. A body of objective data derived from experimentation could be accumulated to provide the basis for defensible decisions by school plant planners regard­ ing the size of classrooms 6. It. is possible to develop school plants which are adequate to meet the educational needs of the youth and which are considerably smaller in size (and therefore cheaper in cost) than what the majority of educators think is adequate 7. The planning process for Seventh-day Adventist schools is similar to, yet distinct from, the planning of larger public schools in that particular problems must be met and distinctive answers sought for them. Recommendations. Based upon the findings of this study, the following recommendations are presented for consideration: 1. In future planning for class room space, care should be taken not to exceed the space allocation recommended in this study which could result in savings in construction costs 2. The planning processes for Seventh-day Adven­ tist schools should be closely analyzed in order to make certain that classrooms are not over-sized 3. The space guidelines developed in this study should be field tested by those committees planning to build Seventh-day Adventist church schools both at the elementary and secondary levels, and revised in the light of experience 4. Additional studies relative to space needs in specific areas of a school should be conducted (dormitory needs, space needs for work-study programs, and etc.) 5. Short seminars or training courses should be developed to prepare Seventh-day Adventist educators and others concerned with school construction in the developing of educational specifications for Seventh-day Adventist schools

The Impact of Soil Conservation Policies on Carbon Sequestration in Agricultural Soils of the Central United States

To evaluate the impact of conservation policies on soil organic carbon in agricultural soils, the authors link information from the 1992 National Resources Inventory (NRI) database and the extensive physical data on soils and climate from the SOILS5 database. These data serve as input for a biophysical process model calibrated for the conditions prevalent in the study region. Results indicate that reducing soil erosion, rather than removing land from agricultural production, is the most effective way to increase carbon sequestration and enhance soil quality

Globular Clusters and Dwarf Spheroidal Galaxies

Traditionally globular clusters and dwarf spheroidal galaxies have been distinguished by using one or more of the following criteria: (1) mass, (2) luminosity, (3) size, (4) mass-to-light ratio and (5) spread in metallicity. However, a few recently discovered objects show some overlap between the domains in parameter space that are occupied by galaxies and clusters. In the present note it is shown that ellipticity can, in some cases, be used to help distinguish between globular clusters and dwarf spheroidal galaxies.Comment: MNRAS (Letters), in pres

Letter, P. W. Babcock to Peleg Clarke Jr., September 16, 1869

This handwritten letter, dated September 16, 1869, is written from P. W. Babcock to Peleg Clarke Jr. requesting a payment draft of thirty-five dollars to pay interest on a note Clarke holds against Oliver Davis. The letter also acknowledges Davis\u27s carelessness in not paying for the interest earlier. The letter also informs Clarke of Davis\u27s current illness of remittent fever.https://scholarsjunction.msstate.edu/fvw-manuscripts-clarke/1069/thumbnail.jp

Control and modeling of a CELSS (Controlled Ecological Life Support System)

Research topics that arise from the conceptualization of control for closed life support systems which are life support systems in which all or most of the mass is recycled are discussed. Modeling and control of uncertain and poorly defined systems, resource allocation in closed life support systems, and control structures or systems with delay and closure are emphasized

The 1995 Farm Bill: Issues, Options, and an Analytical Framework for Integrated Economic and Environmental Policy Assessment

A viable agricultural policy should adapt to any changes occurring within the agricultural sector. With the growing focus on environmentally friendly agriculture, increased role for markets by reducing the influence of farm programs, agricultural-related global climate change, and budgetary pressures, the 1995 Farm Bill can lead the reorienting of farm policies toward achieving these goals and thus preserve the leadership role of the U.S. agricultural sector. The 1995 Farm Bill should enable farmers to retain their competitive edge in the increasingly free global market and also should protect the environment and rural communities. This paper identified key issues and the available options for the upcoming Farm Bill discussions

Nonlinear system controller design based on domain of attaction: An application to CELSS analysis and control

Nonlinear system controller design based on the domain of attraction is presented. This is particularly suited to investigating Closed Ecological Life Support Systems (CELSS) models. In particular, the dynamic consequences of changes in the waste storage capacity and system mass, and how information is used for control in CELSS models are examined. The models' high dimensionality and nonlinear state equations make them difficult to analyze by any other technique. The domain of attraction is the region in initial conditions that tend toward an attractor and it is delineated by randomly selecting initial conditions from the region of state space being investigated. Error analysis is done by repeating the domain simulations with independent samples. A refinement of this region is the domain of performance which is the region of initial conditions meeting a performance criteria. In nonlinear systems, local stability does not insure stability over a larger region. The domain of attraction marks out this stability region; hence, it can be considered a measure of a nonlinear system's ability to recovery from state perturbations. Considering random perturbations, the minimum radius of the domain is a measure of the magnitude of perturbations for which recovery is guaranteed. Design of both linear and nonlinear controllers are shown. Three CELSS models, with 9 to 30 state variable, are presented. Measures of the domain of attraction are used to show the global behavior of these models under a variety of design and controller scenarios