Spectrophotometric technique quantitatively determines NaMBT inhibitor in ethylene glycol-water solutions

Spectrophotometric method, using a ratio-recording ultraviolet-absorption spectrophotometer, permits analysis of NaMBT in ethylene glycol-water solutions with high accuracy. It reduces analysis time, requires smaller samples, and is able to detect extremely small concentrations of mercaptobenzothiazole

Suboptimal compensation of gyroscopic coupling for inertia-wheel attitude control

Suboptimal compensation of gyroscopic coupling for inertia-wheel attitude control by mathematical technique

The collapse of shallow coal mine workings

The present study was -undertaken to investigate the mechanism of void migration and the collapse characteristics of old shallow surface (< 50m), pillar and stall coal mine workings. Simple stereo-photographic techniques have been employed to record these structures where they occur in the high walls of NCB and private opencast coal sites. Several relationships have been identified from this data, and the investigation concludes that the crushing of coal pillars at depth is rare and that the principal mechanism of failure involves the collapse of the roof material into the working. A classification of failure mechanisms based on the frequency and spacing of horizontal and vertical discontinuities relative to the span of the working is proposed. Two distinct situations for analysis are recognised. The first involves the stability of the immediate roof, while the second is concerned with the stability of the 'arch' that develops when the immediate roof beam collapses. Continuous roof beams have been found to be rare in Coal Measures rocks and therefore simple beam analysis is considered to be of little use. Where discontinuities are present Voussoir beam analysis may be appropriate, and Voussoir beam theory has been corrected and extended to overcome some of the problems recognised with the technique. Bulking and arching have been recognised as the 'normal' limiting factors on the height of collapse and are considered as complimentary failure mechanisms. For a 'typical coal mine collapse' situation arching is shown to be the dominant control. However, a review of arching has shown that in general all the theories underestimate the height of collapse. Thus, a statistically derived relationship of (collapse height = 2.68 X span of working) has been proposed as the limiting height for arching situations. Existing bulking relationships have been shown to be rather simplistic and appropriate corrections to the theories are suggested. An analysis of bulking factors derived from colliery discard has shown that a regional variation in this parameter is likely

Preparation of thin polymer films for infrared reaction rate studies

Procedure for preparing thin films for infrared spectrophotometric analysis involves pressing of a neat mixture of reactants between nonreactive thin polymer films with noninterfering absorption bands. Pressing is done under a pressure that gives desirable thickness. Following this process, the film sandwich is cut to accommodate the laboratory instrument

Dealing with imperfect detectability in biological surveys for native grassland management

The default assumption of many environmental impact assessments is that a species that is present at a site will be detected during a survey of that site. However there is now evidence that a range of species have detection probabilities of less than one during biological surveys, and the consequences of failing to detect threatened and invasive species may be severe. A number of methods exist for characterising detectability and determining the number of repeat visits to a site necessary to ensure an acceptably high probability that a resident species will be detected. However, no such method exists for determining the survey duration necessary in a single visit to ensure a reasonable probability of detecting a plant species that is present at a site. In this thesis a new method, based on failure time techniques, is proposed for estimating the time required to detect a plant species during a flora survey. The exponential detection time model presented in this study is demonstrated to be a reliable estimator of the average time to detection of a plant species under a range of simulated scenarios. Using the exponential detection time model introduced in this thesis, the detectability of two threatened plant species (Pimelea spinescens and Dianella amoena) and two invasive weeds (Nassella neesiana and N. trichotoma) in a threatened native grassland community are investigated. Imperfect detection is demonstrated for all four species and a number of observer and environmental factors that influence detectability are identified. In particular, it is demonstrated that experienced observers detect each species more quickly than their less experienced counterparts. Other variables that affect detectability include the search method and cover of the dominant grass species. Under favourable conditions, predicted average detection times range from 26 (P. spinescens) to 41 (D. amoena) minutes per hectare, and estimates of the survey effort required to achieve a probability of 0.80 that the target species will be detected if it is present are between 42 and 66 minutes per hectare. As with other detectability studies, the findings of this research demonstrate that the survey effort required to detect these species increases substantially under suboptimal survey conditions. A multi-species detection time model that characterises the average time to detection according to plant traits and characteristics is also introduced. Variables shown to influence detectability in this model include the lifeform and rarity of the plant, and flower and leaf characteristics. While not able to provide precise and accurate estimates of individual species’ detection probabilities, this model may be used to bound survey effort requirements where no other information exists. The findings of this thesis have important implications for conservation policy and practice in Australia and internationally. In particular, they may be used to inform survey recommendations, including minimum survey effort requirements, for environmental impact assessments and weed surveillance. A number of recommendations for a more effective handling of imperfect detection in conservation policy are made

On the synthesis of suboptimal, inertia-wheel attitude control systems

Suboptimal systems synthesis using motor-driven inertia wheels for attitude contro

Paper Session I-C - Multifunctional Air Revitalization Systems

The end goal in developing air revitalization systems is improved performance and enhanced capability to enable long-duration interplanetary life support. The evolution of current and near-term techniques is the most likely path to achieve future systems in which consumables are regenerated to effect weight and cost savings. Regenerative solid amine sorbents are now in use in the Space Shuttle Extended Duration Orbiter (EDO); currently, the solid amine performs only the carbon dioxide (CO2) removal function. Testing was conducted on solid amines to better understand the behavior during CO2 adsorption and the influences of trace contaminant gases. Tests were conducted, beginning hi 1991, using Thermogravimetric Analysis (TGA) system and on a sorbent column linked to a mass spectrometer and a gas chromatograph to ascertain the ability of the solid amine to remove CO2 and trace contaminants. Solid amine adsorption and desorption test data were obtained for trace contaminants representing corrosive and reactive compounds typical of space cabin atmospheres. Test results show that the solid amine has the ability to regeneratively remove trace contaminants, although some highly corrosive gases bond irreversibly. The TGA system proved to be a rapid, versatile method to screen trace contaminants for effects on solid amine; the column system provided more realistic conditions and analysis of off-gas products. Both analysis tools have provided initial capability to assess regenerative air revitalization techniques that may then be combined to create a multifunctional, closed-loop atmosphere purification system

Incorporating detectability of threatened species into environmental impact assessment

Environmental impact assessment (EIA) is a key mechanism for protecting threatened plant and animal species. Many species are not perfectly detectable and, even when present, may remain undetected during EIA surveys, increasing the risk of site-level loss or extinction of species. Numerous methods now exist for estimating detectability of plants and animals. Despite this, regulations concerning survey protocol and effort during EIAs fail to adequately address issues of detectability. Probability of detection is intrinsically linked to survey effort; thus, minimum survey effort requirements are a useful way to address the risks of false absences. We utilized 2 methods for determining appropriate survey effort requirements during EIA surveys. One method determined the survey effort required to achieve a probability of detection of 0.95 when the species is present. The second method estimated the survey effort required to either detect the species or reduce the probability of presence to 0.05. We applied these methods to Pimelea spinscens subsp. spinescens, a critically endangered grassland plant species in Melbourne, Australia. We detected P. spinescens in only half of the surveys undertaken at sites where it was known to exist. Estimates of the survey effort required to detect the species or demonstrate its absence with any confidence were much higher than the effort traditionally invested in EIA surveys for this species. We argue that minimum survey requirements be established for all species listed under threatened species legislation and hope that our findings will provide an impetus for collecting, compiling, and synthesizing quantitative detectability estimates for a broad range of plant and animal species

Consequences of inconsistently classifying woodland birds

There is a longstanding debate regarding the need for ecology to develop consistent terminology. On one hand, consistent terminology would aid in synthesizing results between studies and ease communication of results. On the other hand, there is no proof that standardizing terminology is necessary and it could limit the scope of research in certain fields. This article is the first to provide evidence that terminology can influence results of ecological studies. We find that researchers are classifying &quot;woodland birds&quot; inconsistently because of their research aims and linguistic uncertainty. Importantly, we show that these inconsistencies introduce a systematic bias to results. We argue that using inconsistent terms can bias the results of studies, thereby harming the field of ecology, because scientific progress relies on the ability to synthesize information from multiple studies

Solar Particle Induced Upsets in the TDRS-1 Attitude Control System RAM During the October 1989 Solar Particle Events

The three large solar particle events, beginning on October 19, 1989 and lasting approximately six days, were characterized by high fluences of solar protons and heavy ions at 1 AU. During these events, an abnormally large number of upsets (243) were observed in the random access memory of the attitude control system (ACS) control processing electronics (CPE) on-board the geosynchronous TDRS-1 (Telemetry and Data Relay Satellite). The RAM unit affected was composed of eight Fairchild 93L422 memory chips. The Galileo spacecraft, launched on October 18, 1989 (one day prior to the solar particle events) observed the fluxes of heavy ions experienced by TDRS-1. Two solid-state detector telescopes on-board Galileo designed to measure heavy ion species and energy, were turned on during time periods within each of the three separate events. The heavy ion data have been modeled and the time history of the events reconstructed to estimate heavy ion fluences. These fluences were converted to effective LET spectra after transport through the estimated shielding distribution around the TDRS-1 ACS system. The number of single event upsets (SEU) expected was calculated by integrating the measured cross section for the Fairchild 93L422 memory chip with average effective LET spectrum. The expected number of heavy ion induced SEUs calculated was 176. GOES-7 proton data, observed during the solar particle events, were used to estimate the number of proton-induced SEUs by integrating the proton fluence spectrum incident on the memory chips, with the two-parameter Bendel cross section for proton SEU's. The proton fluence spectrum at the device level was gotten by transporting the protons through the estimated shielding distribution. The number of calculated proton-induced SEU’s was 72, yielding a total of 248 predicted SEU’s, very close to the 243 observed SEU’s. These calculations uniquely demonstrate the roles that solar heavy ions and protons played in the production of SEU’s during the October 1989 solar particle events