Thermally adaptive building covering field test

This paper represents the first public exhibition of Thermadapt™ building coverings which were invented more than eight years ago. The paper starts with a brief overview of the field of adaptive materials and their applications in various industries. Thermally adaptive building covering sheet fundamentals are explained by laying out the basic structural mechanics of thermally induced gross shape changes in lamina. As a truncated paper, the driving theory, coupon, test chamber and subscale building data could not be included due to length constraints, but will be delivered during oral presentation. Nonetheless, data from outdoor range testing on three independent buildings is presented. These three buildings measuring 1.8m (6 ft) deep x 2.4m (8 ft) wide x 2.1m (7 ft) high showed excellent results. The first was outfitted with Thermadapt™ siding and roofing. The second was outfitted with a variety of different amounts of insulation. The third was used as a control. The configuration of the full-scale test range buildings is shown along with performance data in all midwestern seasons. The data demonstrated that thin thermally adaptive building coverings are as effective as 27 cm (10.5”) of fiberglass insulation, indicating an equivalent R-value of more than 40/cm (100/in). The paper concludes with an overview of the economics of Thermadapt™ building coverings and the intellectual property landscape

Disturbance and the Successional Response of Arctic Plants on Polar Desert Habitats

… The present authors have observed during several summer seasons disturbance-induced succession on the Truelove Lowland of Devon Island (76 N) in the Canadian Arctic Archipelago. In this paper are presented the results of observations of the successional response of three vascular plant species on polar desert microenvironments subjected to vehicle disturbance. The study area is a post-Pleistocene strand flat on the northeast coast of Devon Island. A pronounced series of raised beaches are in evidence from the present coastline inland to the upper marine limit. These relict beaches provide microsites of polar desert conditions in the midst of a landscape dominated chiefly by hydric tundra meadows. As such they represent the xeric portion of a typical arctic "mesotopographic gradient" …. The present writers interpret the plant communities established on these sites to be in equilibrium with the present environment and thus represent climax plant communities. … The values for total plant cover on the vehicle-disturbed pavement are, not unexpectedly, drastically reduced. More interesting, however, are comparisons of the three species in recolonization. The two species found most commonly in undisturbed communities show quite distinctive responses following disturbance. Saxifraga oppositifolia seedlings yielded counts similar to those for undisturbed terrain. Further, in the majority of quadrats on disturbed areas Minuartia rubella was now the major contributor to the total vascular plant cover. Saxifraga oppositifola while prominent numerically was represented chiefly by smaller seedlings and thus contributed substantially less to cover values. Similar results were also obtained on small quadrats artificially denuded of all vegetation in 1969 …. Counts of individuals on four quadrants showed the presence of a number of invading Minuartia rubella seedlings and occasional Saxifraga oppositifolia, but after four years all plots still lacked Dryas integrifolia. … Observations made during the present study indicate that, for these habitats at least, important shifts in the numerical relationships between species occur following vehicle disturbance (and subsequent reduction in community diversity). The sharp increases in populations of Minuartia rubella and the distinctive recolonization rates of Saxifraga oppositifolia and Dryas integrifolia populations may be easily viewed as disturbance-induced succession. The causal reasons for these population responses are not known. All three species appear to produce substantial amounts of seed in the field. These observations do serve to emphasize, however, that our present understanding of the population dynamics of Arctic tundra plants may be inadequate for predictive purposes. It is unlikely, for example, that in selecting native plants for restoring vegetation on disturbed xeric tundra Minuartia rubella would have been favoured over Dryas integrifolia if we were to rely solely on our observations of the two species in undisturbed communities. The study of responses of vegetation to current land manipulations in the Arctic may provide valuable clues to the understanding of the successional process in this region. It is the authors' belief that existing data on succession in tundra in the High Arctic are inadequate for the long-range planning of land use in many tundra habitats, and that greater emphasis should be directed towards this problem in the future

Effects of DDT on the Density and Diversity of Tardigrades

Twenty lichen-bearing tree bark samples were collected from DDT sprayed American elm trees (Ulmus Americana L.) in central Iowa. Twenty comparable samples were collected from an adjacent nontreated habitat. A tardigrade density of 4 individuals collected from the treated habitat was found to differ significantly (P \u3c .01) from a density of 97 individuals collected from the non-treated area. Margalef\u27s diversity index (D=S-1/1n N) determinations were found to be 0.00 and 0.44 for the treated and non-treated habitats, respectively. Tardigrade species organization within the nontreated habitat did not differ significantly from that as predicted by MacArthur\u27s broken-stick model, suggesting that tardigrade species occupy contiguous, non-overlapping niches within a lichen-bearing tree bark ecosystem. It is suggested that measurements depicting microfauna-lichen-tree bark relationships might serve as useful criteria in evaluating pesticide stress effects on total forest ecosystems

Design, Manufacturing and Test of a High Lift Secondary Flight Control Surface with Shape Memory Alloy Post-Buckled Precompressed Actuators

The use of morphing components on aerospace structures can greatly increase the versatility of an aircraft. This paper presents the design, manufacturing and testing of a new kind of adaptive airfoil with actuation through Shape Memory Alloys (SMA). The developed adaptive flap system makes use of a novel actuator that employs SMA wires in an antagonistic arrangement with a Post-Buckled Precompressed (PBP) mechanism. SMA actuators are usually used in an antagonistic arrangement or are arranged to move structural components with linearly varying resistance levels similar to springs. Unfortunately, most of this strain energy is spent doing work on the passive structure rather than performing the task at hand, like moving a flight control surface or resisting air loads. A solution is the use of Post-Buckled Precompressed (PBP) actuators that are arranged so that the active elements do not waste energy fighting passive structural stiffnesses. One major problem with PBP actuators is that the low tensile strength of the piezoelectric elements can often result in tensile failure of the actuator on the convex face. A solution to this problem is the use of SMA as actuator material due to their tolerance of tensile stresses. The power consumption to hold deflections is reduced by approximately 20% with the Post-Buckled Precompressed mechanism. Conventional SMAs are essentially non-starters for many classes of aircraft due to the requirement of holding the flight control surfaces in a given position for extremely long times to trim the vehicle. For the reason that PBP actuators balance out air and structural loads, the steady-state load on the SMAs is essentially negligible, when properly designed. Simulations and experiments showed that the SMAPBP actuator shows tip rotations on the order of 45°, which is nearly triple the levels achieved by piezoelectric PBP actuators. The developed SMAPBP actuator was integrated in a NACA0012 airfoil with a flexible skin to carry out wind tunnel tests

Devon Island Programs, 1972-1973

From April 1972 through the 1973 field season, the Arctic Institute's research base on the northeast coast of Devon Island (75°40'N, 84°40'W) will be the seat of operations for scores of investigators and their field assistants. The major research program continues to be a large integrated tundra ecosystem study sponsored by the Canadian International Biological Program (IBP). The Base Camp is also being used by groups of researchers from the Canadian Wildlife Survey, and from the Polar Continental Shelf Project. The two AINA-sponsored projects are summarized below. ... During the summer of 1972, and the winter of 1972-73, the camp was used as a communications centre, and for providing other assistance to research stations established on Coburg Island and on the Carey Islands (Greenland) which are part of the Institute's North Water Project. ... [1] ECOLOGICAL STUDIES OF SEDGE-DOMINATED MEADOW TUNDRA. During the 1972 field season studies were continued on the ecology of sedge-dominated meadows. ... Studies of rhizome behaviour were continued. Complete systems were excavated and collected at five locations. Rhizome growth was monitored on selected individual plants. ... Population characteristics of sedges invading small ponds and drained lake systems were further investigated. Three-and-a-half weeks were spent at the National Museum of Natural History camp on Bathurst Island. ... six sedge meadows were selected and analysed for comparison with the Devon Island meadows. Five permanent plots were also established and mapped and populations of Carex stans collected for both seed and morphological measurements. A project to investigate the revegetation of vehicle-disturbed sedge meadows with native Carex species was also initiated. ... Analysis of plantings of Carex stans as well as natural revegetation in some blocks will be monitored in following seasons. ... [2] VEGETATION STUDIES ON THE INTERIOR PLATEAU. ... A 2.4 km transect was placed east from the Plateau margin to the interior. The transect crossed a number of habitats, including solifluction terraces, stripes and sorted nets. Four maximum-minimum thermometer enclosures and two hygrothermograph stations were set out to determine microclimatic variations along the line. Forty 25 m² quadrats were placed at 80 m intervals along the transect for vegetation analysis. At each plot, the percentage cover of rock, soil, vascular plants and bryophytes was calculated; species composition was determined and voucher specimens from each quadrat were collected. Lichen specimens were also collected for later taxonomic determinations in the laboratory. Surface soil samples from each plot were collected for mechanical and chemical analysis. ... At 5 points along the transect, regular sampling of soil at 0 and 15 cm was undertaken to determine a curve of seasonal soil moisture. These values will be compared with concurrent samples taken in nonsorted circles on the Lowland. In addition to the 40 systematic plots, 5 additional sites were also ana1ysed. ... Comparisons with the transect data should indicate if the visual homogeneity of the vegetation on the Plateau is constant over a large area. A high density bryophyte community at the head of a drainage system and one solifluction terrace characterized by Alopecurus were also analysed. These sites were unusual in that they both had vegetation cover values greater than 40 per cent. Other plots on the Plateau had values of 1 to 4 per cent. ..

Analytical electron microscopy of LDEF impactor residues

The LDEF contained 57 individual experiment trays or tray portions specifically designed to characterize critical aspects of meteoroid and debris environment in low-Earth orbit (LEO). However, it was realized from the beginning that the most efficient use of the satellite would be to characterize impact features from the entire surface of the LDEF. With this in mind particular interest has focused on common materials facing in all 26 LDEF facing directions; among the most important of these materials has been the tray clamps. Therefore, in an effort to better understand the nature and flux of particulates in LEO, and their effects on spacecraft hardware, we are analyzing residues found in impact features on LDEF tray clamp surfaces. This paper summarizes all data from 79 clamps located on Bay A & B of the LDEF. We also describe current efforts to characterize impactor residues recovered from the impact craters, and we have found that a low, but significant, fraction of these residues have survived in a largely unmelted state. These residues can be characterized sufficiently to permit resolution of the impactor origin. We have concentrated on the residue from chondritic interplanetary dust particles (micrometeoroids), as these represent the harshest test of our analytical capabilities