1,055 research outputs found
Space debris measurement program at Phillips Laboratory
Ground-based optical sensing was identified as a technique for measuring space debris complementary to radar in the critical debris size range of 1 to 10 cm. The Phillips Laboratory is building a staring optical sensor for space debris measurement and considering search and track optical measurement at additional sites. The staring sensor is implemented in collaboration with Wright Laboratory using the 2.5 m telescope at Wright Patterson AFB, Dayton, Ohio. The search and track sensor is designed to detect and track orbital debris in tasked orbits. A progress report and a discussion of sensor performance and search and track strategies will be given
A low-mass faraday cup experiment for the solar wind
Faraday cups have proven to be very reliable and accurate instruments capable of making 3-D velocity distribution measurements on spinning or 3-axis stabilized spacecraft. Faraday cup instrumentation continues to be appropriate for heliospheric missions. As an example, the reductions in mass possible relative to the solar wind detection system about to be flown on the WIND spacecraft were estimated. Through the use of technology developed or used at the MIT Center for Space Research but were not able to utilize for WIND: surface-mount packaging, field-programmable gate arrays, an optically-switched high voltage supply, and an integrated-circuit power converter, it was estimated that the mass of the Faraday Cup system could be reduced from 5 kg to 1.8 kg. Further redesign of the electronics incorporating hybrid integrated circuits as well as a decrease in the sensor size, with a corresponding increase in measurement cycle time, could lead to a significantly lower mass for other mission applications. Reduction in mass of the entire spacecraft-experiment system is critically dependent on early and continual collaborative efforts between the spacecraft engineers and the experimenters. Those efforts concern a range of issues from spacecraft structure to data systems to the spacecraft power voltage levels. Requirements for flight qualification affect use of newer, lighter electronics packaging and its implementation; the issue of quality assurance needs to be specifically addressed. Lower cost and reduced mass can best be achieved through the efforts of a relatively small group dedicated to the success of the mission. Such a group needs a fixed budget and greater control over quality assurance requirements, together with a reasonable oversight mechanism
Sporadic Bovine Encephalomyelitis
The infectious agent of sporadic bovine encephalomyelitis has now been propagated for nearly three years in developing chick embryos.This has afforded a convenient method of propagation while studying the causal agent. It is interesting that during all of this time in chick embryos, which represents more than 135 passages in series, there has been no apparent variation in the character of the infectious agent. It is as pathogenic for guinea pigs and cattle as when first isolated. Failure to recognize anything in the tissues of affected animals that would indicate the exact nature of the entity which causes the disease, led to an extension of the histological study to infected chick embryos, especially their membranes and yolk sacs
Report of the panel on lithospheric structure and evolution, section 3
The panel concluded that NASA can contribute to developing a refined understanding of the compositional, structural, and thermal differences between continental and oceanic lithosphere through a vigorous program in solid Earth science with the following objectives: determine the most fundamental geophysical property of the planet; determine the global gravity field to an accuracy of a few milliGals at wavelengths of 100 km or less; determine the global lithospheric magnetic field to a few nanoTeslas at a wavelength of 100 km; determine how the lithosphere has evolved to its present state via acquiring geologic remote sensing data over all the continents
The Constitutionality of the American Legion Plan to Perpetuate Peace
The popularly named Universal Draft bill espoused by the American Legion was the occasion of extended hearings before the War Policies Commission in March, 1931. During those hearings many questions were raised concerning the powers of the Congress and of the President. The material of this article was incorporated in a memorandum prepared and filed in response to those questions by Mr. McNutt, Mr. O\u27Neil and Colonel Robbins, acting on behalf of the American Legion. Mr. McNutt and Mr. O\u27Neil are Past National Commanders of the Legion and are members of the Indiana and Nebraska bars, respectively. Colonel Robbins is Chairman of the National Defense Committee, former Assistant Secretary of War, and a member of the Iowa bar
The Constitutionality of the American Legion Plan to Perpetuate Peace
The popularly named Universal Draft bill espoused by the American Legion was the occasion of extended hearings before the War Policies Commission in March, 1931. During those hearings many questions were raised concerning the powers of the Congress and of the President. The material of this article was incorporated in a memorandum prepared and filed in response to those questions by Mr. McNutt, Mr. O\u27Neil and Colonel Robbins, acting on behalf of the American Legion. Mr. McNutt and Mr. O\u27Neil are Past National Commanders of the Legion and are members of the Indiana and Nebraska bars, respectively. Colonel Robbins is Chairman of the National Defense Committee, former Assistant Secretary of War, and a member of the Iowa bar
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Spontaneous discrimination of urine odours in wild African lions (Panthera leo)
Olfactory communication is the primary mode of communication for many mammals, yet research on this form of signalling is still largely descriptive in most species. Thus, despite the apparent importance of scent-marking in the social lives of wild felids, experimental studies directly investigating the function of olfactory communication are lacking. We conducted scent presentation experiments to investigate whether wild African lions can discriminate another lion's social group and sex from a sample of its urine. Our results indicated that lion urine has the potential to signal depositor sex and social group, and that lions can use urine to discriminate males from females and residents from non-residents. The response of lions to urine was also dependent on both the sex and age of the subject receiving the presentation. Female lions responded less frequently to urine from resident females than to either non-resident females or resident males. Males responded more strongly to urine from resident males than resident females, but did not appear to differentiate urine from non-resident and resident females. Observations of flehmen and further scent-marking responses from lions provide additional evidence that lion urine functions in scent-marking. These results establish that urine scent-marks contain sufficient information for receivers to discriminate the sex and social affiliation of the signaller, and are the first to experimentally demonstrate the functional relevance of scent-marking in African lions
An Evaluation of the Effects of Dredging Within the Arkansas River Navigation System: Volume I - Introduction, Summary and Conclusions, and Recommendations
The Arkansas River originates in the eastern slopes of the Rocky Mountains near Leadville, Colorado, and extends through Kansas, Oklahoma, and Arkansas, where it flows into the Mississippi River. The Arkansas River is approximately 1,450 miles in length and drains a total area of 160,500 square miles. The river and its tributaries have been developed for navigation, flood control, and hydro-electric power, as well as recreational purposes under the River and Harbor Act of July 24, 1946. The development of the Arkansas River for recreational use will be completed in the near future. The McClellan-Kerr Arkansas River Navigation System was completed from its confluence with the Mississippi River to Little Rock in 1969 and subsequently to Fort Smith by 1970. Lock and dam construction, channel realignment and other activities have resulted in many changes in the river’s natural characteristics
Swine Brucellosis: Results of Vaccination Experiment
This discussion will consist of a consideration of the results obtained in a recently concluded brucellosis vaccination or exposure experiment in hogs together with a brief review of the results reported by others
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