Circular 73

An assessment of Growth of Infrastructure Booms have been a common element in the development of frontier areas in the 19th and 20th centuries. Most commonly, the booms have been associated with resource development such as the mineral booms of the western United States. Booms usually involve some type of dramatic short- term change which has wide-ranging implications (Gilmore, 1976). Since the arrival of the Russians in Alaska, six major booms have occurred: furs, whales, salmon, minerals, military, and petroleum. Each of these booms has, to some degree, created changes in the landscape of Alaska, in particular, the infrastructural base, which in turn has facilitated subsequent development, either another major boom, or a smaller development. For example, agricultural development has been enhanced by mineral, military, and petroleum booms in Alaska. The cumulative impact on infrastructure of more than one boom, or multibooms, as it is referred to here, is the focus of this paper. One problem encountered in studying booms is that there is no general agreement on what constitutes a boom. Detailed studies of booms in communities such as Dixon’s (1978) analysis of Fairbanks and Gilmore’s multi-community work in the Great Plains—Rocky •mountain regions, contained no specific definition of the term “boom”. Yet it was clear in each study that something dramatic had occurred. More general historical studies of the Western mineral bonanzas (Greever, 1963) or the Klondike gold rush (Berton, 1958) likewise suggest a number of factors such as population rise, influx of money, resource extraction, and infrastructure expansion. But in each case, there is no specific factor or define rate of something that specifically qualifies a time period as a boom. In this study, we are concerned with dramatic change of events which have had a major impact on the geographic landscape of an area, As a framework for the initial study, we review those events which have been given attention as boom-type activities in the historical literature of Alaska (Rogers, 1962; Naske and Slotnick, 1987)

Misc. Pub. 92-3

Entrance to the Chena Hot Springs Road is only 5 miles from downtown Fairbanks. The road provides an excellent opportunity to see an example o f the diversity of agricultural production in the Tanana Valley

Prepubertal Ontogeny of Luteinizing Hormone-Releasing Hormone Immunoreactivity in Developing Pig Brain

Luteinizing hormone-releasing hormone (LHRH, GnRH) is a 10-amino acid peptide produced in the brain that regulates the release of LH from the pituitary gland. LH is crucial for initiating the successful ovulation of mature ovarian follicles (Graafian follicles) and transforming the ovulated follicle into a steroid-secreting corpus luteum. In the male, LH causes Leydig cells in the testis to secrete testosterone, a hormone essential for male sexual behavior secretory activity of accessory glands of the reproductive tract, muscle accretion, and spermatogenesis. The focus of this study was to determine the prepubertal ontogeny of LHRH-like immunoreactivity (LHRH-IR) in the male Chinese Meishan pig. The Meishan breed is known for reproductive traits, including increased litter size and precocious puberty, but slow growth and obesity. Brains of animals from gestational day (g) 30, 50, 70, 90, and 110 and postnatal day (pn) 1, 10, 20, and 50 (duration of pregnancy averages 114 days) were processed by a standard immunohistochemical technique utilizing a commercially available rabbit anti-LHRH antibody. Coronal sections of the brain revealed LHRH-IR in cell bodies and fibers at g30 entering the brain via the terminal nerve and in the septal region of the basal telencephalon. The numbers of LHRH-IR cells increased at g50 and cells were localized to the septum, organum vasculosum of the lamina terminalis, optic area, and lateral hypothalamus whereas immunoreactive fibers were present throughout the septum and hypothalamus and had reached the median eminence, the lowest connecting link to the anterior pituitary gland. Results from this study indicate that LHRH may be present in the Meishan brain earlier during development and fibers containing LHRH-IR appear in the median eminence (lower part of the hypothalamus near the pituitary gland) earlier than previously reported for the domestic pig. These results suggest a breed difference in the ontogeny of reproductive control systems in the pig. An understanding of the LHRH neuronal network within the brain and hormones and exteroceptive factors that affect its secretion of LHRH that, in turn, causes gonadotropin (luteinizing hormone and follicle stimulating hormone) secretion by the pituitary gland will reveal neuroendocrine mechanisms regulating reproduction in the pig

Optimized placement of parasitic vibration energy harvesters for autonomous structural health monitoring

Energy harvesting, based on sources including vibration and thermal gradients, has been exploited in recent years to power telemetry, small devices, or to charge batteries or capacitors. Generating the higher levels of power which have thus far been required to run sensor systems such as those needed for structural health monitoring has been more challenging. In addition, harvesters such as those required to capture vibration often require additional elements (e.g. cantilevers) to be added to the structure and harvest over a relatively narrow band of frequencies. In aerospace applications, where weight is at a premium and vibrations occur over a broader range of frequencies, this is non-ideal. With the advent of new, lower power monitoring systems, the potential for energy harvesting to be utilized is significantly increased. This article optimizes the placement of a set of parasitic piezoelectric patches to harvest over the broad band of frequencies found in an aircraft wing and validates the results experimentally. Results are compared with the requirements of a low-power structural health monitoring system, with a closing of the gap between the energy generated and that required being demonstrated

Innovative Uses of Co-operative Housing Assets

As housing co-operatives start to reach the point where they are retiring their mortgages, questions arise as to whether and how those assets might be leveraged to further support the needs of the affordable and co-operative housing sector. This is the final report of a research project to explore those questions, specifically in Alberta and British Columbia, Canada.BC-Alberta Social Economy Research Alliance (BALTA) Funder: Social Sciences and Humanities Research Council of Canada (SSHRC

Improved acoustic emission source location during fatigue and impact events in metallic and composite structures

In order to overcome the difficulties in applying traditional Time-Of Arrival (TOA) techniques for locating Acoustic Emission (AE) events in complex structures and materials, a technique termed “delta-t mapping” was developed. This paper presents a significant improvement on this, in which the difficulties in identifying the precise arrival time of an AE signal are addressed by incorporating the Akaike Information Criteria (AIC). The performance of the TOA, the delta-t mapping and the AIC delta-t mapping techniques is assessed by locating artificial AE sources, fatigue damage and impact events in aluminium and composite materials respectively. For all investigations conducted the improved AIC delta-t technique shows a reduction in average Euclidean source location error irrespective of material or source type. For locating H-N sources on a complex aluminium specimen the average source location error (Euclidean) is 32.6, (TOA), 5.8 (delta-t) and 3mm (AIC delta-t). For locating fatigue damage on the same specimen the average error is 20.2, (TOA), 4.2 (delta-t) and 3.4mm (AIC delta-t). For locating H-N sources on a composite panel the average error is 19.3, (TOA), 18.9 (delta-t) and 4.2mm (AIC delta-t). Finally the AIC delta-t mapping technique had the lowest average error (3.3mm) when locating impact events when compared with the delta-t (18.9mm) and TOA (124.7mm) techniques. Overall the AIC delta-t mapping technique is the only technique which demonstrates consistently the lowest average source location error (greatest average error 4.2mm) when compared with the delta-t (greatest average error 18.9mm) and TOA (greatest average error 124.7mm) techniques. These results demonstrate that the AIC delta-t mapping technique is a viable option for AE source location, increasing the accuracy and likelihood of damage detection, irrespective of material, geometry and source type

Advanced acoustic emission source location in aircraft structural testing

Acoustic emission (AE) is an in situ Structural Health Monitoring (SHM) technique, where a structure is monitored for the ultrasonic waves produced due to crack growth. A major challenge with AE when applied to aircraft, and other complex structures, is that wave propagation is significantly affected by stiffeners, holes, thickness changes and other complexity. This reduces the accuracy of traditional source location techniques, that are based on a singular propagating wave speed. The Delta-T method enables higher levels of accuracy by mapping the structure and accounting for these changes. In this work AE monitoring equipment was installed on a section of an aluminium Airbus A320 wing. Location trials showed the Delta-T technique improved the average error from 85mm to 23mm, for artificial Hsu-Nielson sources, compared to the commercial standard technique. Testing under fatigue however demonstrated the challenges encountered when inspecting 3D structures (due to multiple signal paths) with significant levels of background noise. Of two cracks identified in the structure, the first of these was successfully detected and located, whilst the other was missed due to high machine noise and unrepresentative loading

Sonification of numerical data for education

Sonification is the use of non-speech audio to convey information. In this article, sonifications are representations of plots aimed at improving the accessibility of teaching materials. The electronic nature of sonifications means that they can be deployed to students via teaching interfaces such as virtual learning environments. We describe a two-phase study that explores sonifications of plots as a teaching tool in the context of distance learning in STEM. The overall objective of these two phases was to begin to assess the suitability of audio versions of graphs as a teaching tool for non-sighted and sighted students. In the first phase the effectiveness of sonifications within a small group of participants who took part in activities like those encountered in a distance learning setting was explored. We found that even though sonifications were new to them, participants were able to use them to gain impressions of the corresponding plots. The second phase deployed sonifications to all students on an Open University (OU) module. Although many of the students who chose to respond did so negatively, some found the sonifications an interesting augmentation of the plot. Overall, we demonstrate that for a subset of students, information in a plot can be communicated using sonifications