Controlled Environment Agriculture: A Pilot Project

The controlled-environment agricultural (CEA) project discussed in this report was first conceived for the Wildwood Air Force Station in Kenai, Alaska, in 1972. The region contained high unemployment and a U.S. Air Force Station that had just closed. The Kenai Native Association, Inc. (KNA), was to take possession of the Air Force Station through land transfers associated with the Alaska Native Claims Settlement Act, and this corporation was interested in expanding business and employment opportunities for local people. The University of Alaska Agricultural Experiment Station (AES) contacted KNA to determine if it had a facility which might be adaptable for use in a research and development program in controlled- 1 environment agriculture. It was determined that such a facility was available. Subsequently, AES and KNA contacted the General Electric Company (GE) in Syracuse, New York, to determine its interest in such a project. GE had extensive background in lighting technology and environmental control systems and the engineering capability to develop a total system for CEA production. It was agreed that GE would provide technological expertise and AES would provide horticultural and economic expertise for the growing and marketing of a variety of salad crops. KNA would manage the project, employ the nontechnical people, and provide the building. The Wildwood site was selected because it contained two buildings which were thought to be well suited for CEA production. One building would provide sufficient inside space for a 1/4-acre pilot production plant, nine small research modules , a laboratory , offices, a training area, and space for preparing the crop for shipping. A second building near the first contained three diesel generators which were to be converted to natural gas to provide power for the production facility.The Controlled Environment Agriculture Project at Wildwood Village, Kenai, Alaska, spanned a period of five years. During that time, three agencies: Kenai Native Association, Inc.; General Electric Company; and University of Alaska Agricultural Experiment Station , were responsible for the management, research, and production activities. Many persons from these agencies who participated in all phases of the project are acknowledged for their participation and support. This report summarizes work began in 1972 and concluded in 1977 on controlled-environment agriculture in facilities located at Wildwood Village, Kenai, Alaska, managed by the Kenai Native Association , Inc. The authors wish to express their appreciation to all those who have participated in the preparation of this bulletin. Particular acknowledgment is given to: Dr. Gerald Carlson, U.S .D.A., Beltsville, Maryland; Dr. Donald Dinkel, University of Alaska, Agricultural Experiment Station; Dr. Delbert Hemphill, Oregon State University ; John Monfor, Kenai Native Association, Inc.; Dr. Eion Scott, General Electric Company; and Dr. Norman Whittlesey, Washington State University, who thoroughly reviewed the contract document

Path properties of the solution to the stochastic heat equation with L\'evy noise

We consider sample path properties of the solution to the stochastic heat equation, in $\mathbb{R}^d$ or bounded domains of $\mathbb{R}^d$, driven by a L\'evy space-time white noise. When viewed as a stochastic process in time with values in an infinite-dimensional space, the solution is shown to have a c\`adl\`ag modification in fractional Sobolev spaces of index less than $-\frac d 2$. Concerning the partial regularity of the solution in time or space when the other variable is fixed, we determine critical values for the Blumenthal-Getoor index of the L\'evy noise such that noises with a smaller index entail continuous sample paths, while L\'evy noises with a larger index entail sample paths that are unbounded on any non-empty open subset. Our results apply to additive as well as multiplicative L\'evy noises, and to light- as well as heavy-tailed jumps

Estimating exploitable stock biomass for the Maine green sea urchin (Strongylocentrotus droebachiensis) fishery using a spatial statistics approach

The objective of this study was to investigate the spatial patterns in green sea urchin (Strongylocentrotus droebachiensis) density off the coast of Maine, using data from a fishery-independent survey program, to estimate the exploitable biomass of this species. The dependence of sea urchin variables on the environment, the lack of stationarity, and the presence of discontinuities in the study area made intrinsic geostatistics inappropriate for the study; therefore, we used triangulated irregular networks (TINs) to characterize the large-scale patterns in sea urchin density. The resulting density surfaces were modified to include only areas of the appropriate substrate type and depth zone, and were used to calculate total biomass. Exploitable biomass was estimated by using two different sea urchin density threshold values, which made different assumptions about the fishing industry. We observed considerable spatial variability on both small and large scales, including large-scale patterns in sea urchin density related to depth and fishing pressure. We conclude that the TIN method provides a reasonable spatial approach for generating biomass estimates for a fishery unsuited to geostatistics, but we suggest further studies into uncertainty estimation and the selection of threshold density values

Reliability analysis of continuous fiber composite laminates

A composite lamina may be viewed as a homogeneous solid whose directional strengths are random variables. Calculation of the lamina reliability under a multi-axial stress state can be approached by either assuming that the strengths act separately (modal or independent action), or that they interact through a quadratic interaction criterion. The independent action reliability may be calculated in closed form, while interactive criteria require simulations; there is currently insufficient data to make a final determination of preference between them. Using independent action for illustration purposes, the lamina reliability may be plotted in either stress space or in a non-dimensional representation. For the typical laminated plate structure, the individual lamina reliabilities may be combined in order to produce formal upper and lower bounds of reliability for the laminate, similar in nature to the bounds on properties produced from variational elastic methods. These bounds are illustrated for a (0/plus or minus 15)sub s Graphite/Epoxy (GR/EP) laminate. And addition, simple physically plausible phenomenological rules are proposed for redistribution of load after a lamina has failed. These rules are illustrated by application to (0/plus or minus 15)sub s and (90/plus or minus 45/0)sub s GR/EP laminates and results are compared with respect to the proposed bounds

An MDL approach to the climate segmentation problem

This paper proposes an information theory approach to estimate the number of changepoints and their locations in a climatic time series. A model is introduced that has an unknown number of changepoints and allows for series autocorrelations, periodic dynamics, and a mean shift at each changepoint time. An objective function gauging the number of changepoints and their locations, based on a minimum description length (MDL) information criterion, is derived. A genetic algorithm is then developed to optimize the objective function. The methods are applied in the analysis of a century of monthly temperatures from Tuscaloosa, Alabama.Comment: Published in at http://dx.doi.org/10.1214/09-AOAS289 the Annals of Applied Statistics (http://www.imstat.org/aoas/) by the Institute of Mathematical Statistics (http://www.imstat.org

Getting the Swing of Surface Gravity

Sports are a popular and effective way to illustrate physics principles. Baseball in particular presents a number of opportunities to motivate student interest and teach concepts. Several articles have appeared in this journal on this topic, illustrating a wide variety of areas of physics. In addition, several websites and an entire book are available. In this paper we describe a student-designed project that illustrates the relative surface gravity on the Earth, Sun and other solar-system bodies using baseball. We describe the project and its results here as an example of a simple, fun, and student-driven use of baseball to illustrate an important physics principle