Bearing detection in the presence of two sources of varying coherence using the complex cepstrum

The effect of the presence of two acoustic sources (one, the primary, whose location is to be detected) of varying coherence on a cepstral bearing finding procedure is experimentally studied. The coherence between the acoustic sources was altered by adding random noise of various SNR (signal-to-noise ratio) to the input signal of the primary source; the same base signal being fed to both sources. The results demonstrate that, when block liftering is used, the primary source bearing is reliably estimated for coherences as low as gamma sup 2 greater than or approx equal to 0.5. The results also imply that background noise (unreflected) of SNR greater than or approx equal to 10 dB will not markedly affect the accuracy of the bearing estimation algorithm

The role of SRMS in satellite servicing

The standard configuration of the shuttle remote manipulator system (RMS) is reviewed and the role of the RMS in satellite servicing is discussed. The RMS tasks include payload deployment, retrieval/berthing, large spacecraft assembly/module exchange, assist astronaut extravehicular servicing, and remote servicing. The potential growth of the RMS to increase its utilization and improve its performance is also addressed. The projected concepts include dual arm operation, a remote mounted RMS, and special purpose end effectors. In particular, a universal service tool system with both remote and manual modes of operation is described

Desktop analysis to inform the design for megafauna monitoring within the Reef 2050 Integrated Monitoring and Reporting Program: final Report of the shorebirds team in the megafauna expert group

The shorebird subgroup of the larger Megafauna Expert Group was tasked with evaluating the adequacy of existing shorebird monitoring activities, and suggesting indices to achieve the objectives and requirements of the Reef 2050 Integrated Monitoring and Reporting Program (RIMReP). This evaluation was undertaken by directly addressing the specific objectives and outcomes provided for the ‘Desktop Analysis Phase’ of the RIMReP process as applicable to shorebirds.An accessible copy of this report is not yet available from this repository, please contact [email protected] for more information

Interaction of gases with lunar materials

The surface chemistry of Apollo 17 lunar fines samples 74220 (the orange soil) and 74241 (the gray control soil) has been studied by measuring the adsorption of nitrogen, argon, and oxygen (all at 77 K) and also water vapor (at 20 or 22 C). In agreement with results for samples from other missions, both samples had low initial specific surface areas, consisted of nonporous particles, and were attacked by water vapor at high relative pressure to give an increased specific surface area and create a pore system which gave rise to a capillary condensation hysteresis loop in the adsorption isotherms. In contrast to previous samples, both of the Apollo 17 soils were partially hydrophobic in their initial interaction with water vapor (both samples were completely hydrophilic after the reaction with water). The results are consistent with formation at high temperatures without subsequent exposure to significant amounts of water

Applications of Skylab EREP photographs to mapping landforms and environmental geomorphology in the Great Plains and Midwest

The following evaluations of Skylab photographs were undertaken: (1) the 1290 Skylab S190A and S190B photographs of Illinois, Iowa, Kansas, Missouri, Nebraska, and South Dakota were evaluated in detail in terms of coverage, cloud cover, photographic quality, endlap, detectability of roads and stereorelief, and utility for geomorphologic mapping, and (2) the utility of the Skylab photos were tested for interpretive analytic mapping of geomorphologic features over large areas representative of different parts of this region. Photointerpretative maps of analytic geomorphology were obtained for various test areas representative of the varied landscapes in the region. These maps are useful for regional land-use planning, ground-water exploration, and other environmental geomorphologic-geologic applications. Compared with LANDSAT-1 MSS images, Skylab photos afford almost as extensive overviews of large areas but in considerably greater detail, and for many SL photos, moderate stereorelief. However, repetitive multiseasonal, cloud-free coverage by high-quality photos is very limited and many areas have no coverage at all

Interaction of gases with lunar materials

Quantitative efforts to assess the surface properties of lunar fines, particularly water induced porosity are discussed. Data show that: (1) changes induced in lunar fines are not visible in high energy electron micrographs, (2) scanning micrographs show no change in particle size distribution as a result of reaction with water, (3) water induced changes are internal to the particles themselves, (4) normal laboratory atmosphere blocks alteration reaction with water, and (5) surface properties of mature lunar soils appear to be almost independent of chemical composition and mineralogy, but there are some variations in their reactivity toward water

Using small reverse cycle air conditioners in relocatable classrooms - a case study

A 9-month study of four relocatable school buildings, each retro-fitted with small reverse cycle air conditioners (ACs), was conducted to investigate their effectiveness in heating and cooling the classrooms. A comparison with data from previous studies found the energy used by the ACs for heating these temporary classrooms was only 19&ndash;20% of the energy used by individual gas heaters installed in permanent classrooms. When equipment efficiencies were considered, the AC units supplied 20&ndash;27% less energy to heat the classrooms. The possible reasons for this reduction in supplied energy are explored in this paper. CO2 emissions for the AC units in heating mode, however, were calculated to be 16% greater than for individual gas heaters. The AC units were also used for cooling and on an average the total annual energy consumption for heating and cooling was found to be 11.6 kWh m&minus;2. Responses to a small survey of staff and students about the use and operation of the conditioners are presented. Their responses were more favourable than the predictions of comfort levels in the classrooms using the Predicted Mean Vote&ndash;Predicted Percentage of Dissatisfaction (PMV&ndash;PPD) model, which indicated &ldquo;uncomfortable&rdquo; conditions on average summer days at 3:00 p.m. and average winter days at 10:00 a.m. Background noise levels in the classrooms with the air conditioners in use were above the recommended maximum design level of 45 dB(A); levels of up to 65 dB(A) were measured.<br /

Simulation of condensation problems in a roller-skating centre

A commercial roller-skating centre in southern Australia had condensation problems on both the roof and floor. The building is a typical warehouse-type structure with a high level of natural ventilation due to poor construction and permanently open vents. A computer model of the building, using the thermal simulation software TRNSYS, was calibrated from a sensitivity analysis of three key parameters, namely air exchange rate, roof surface heat transfer coefficient and deep ground temperature. The predicted times of condensation on the roof were compared with site observations. The time of year was predicted with acceptable accuracy, although earlier in the morning than had been observed. The effect of installing foil insulation in the roof was simulated. Under normal winter conditions, this modification was enough to stop the condensation. However, in unusually cold and humid conditions, condensation still occurred on both surfaces. This was overcome by heating the floor (15 W/m 2 ) for approximately eight hours. Subsequent modifications have demonstrated the value of the simulations.<br /

Sustaining entrepreneurial business: a complexity perspective on processes that produce emergent practice

This article examines the management practices in an entrepreneurial small firm which sustain the business. Using a longitudinal qualitative case study, four general processes are identified (experimentation, reflexivity, organising and sensing), that together provide a mechanism to sustain the enterprise. The analysis draws on concepts from entrepreneurship and complexity science. We suggest that an entrepreneur’s awareness of the role of these parallel processes will facilitate their approaches to sustaining and developing enterprises. We also suggest that these processes operate in parallel at multiple levels, including the self, the business and inter-firm networks. This finding contributes to a general theory of entrepreneurship. A number of areas for further research are discussed arising from this result