18,372 research outputs found
Shuttle system ascent aerodynamic and plume heating
The shuttle program provided a challenge to the aerothermodynamicist due to the complexity of the flow field around the vehicle during ascent, since the configuration causes multiple shock interactions between the elements. Wind tunnel tests provided data for the prediction of the ascent design heating environment which involves both plume and aerodynamic heating phenomena. The approach for the heating methodology based on ground test firings and the use of the wind tunnel data to formulate the math models is discussed
Cohabitation in North Dakota: A Socio-Legal Examination of the Congruence of the Law and Attitudes Towards Living Arrangements Among College Students
The political wrangling over cohauitation law has been an ongoing ordeal in North Dakota politics in recent years. Even more so since there have been multiple failed attempts to have the State’s law panning cohabitation repealed. The purpose of this thesis is to determine attitudes toward cohabitation and its components from a sample of college students. There were a total of 945 participants who took part in the study which called for them to fill out a short survey. The survey consists of three parts.
Pari I includes such items as race, sex, gender, etc. basically demographic data. Part II includes survey items seeking information about current living arrangements. These were especially directed at those who were living in cohabitive relationships / households. Part III consists of a series of eleven Likert statements asking students to rate their attitudes toward the issue cohabitation.
Results indicate that an overall majority of students surveyed did not favor the cohabitation lifestyle in general. However, many did ag, 3 that the number of couples engaging in these types of living arrangements would increase in the coming years despite the law against it
A Case Study of Remediation for a Fifth Grade Boy with Reading Disabilities
The purpose of this study was to provide formal research evidence as to the effectiveness of the remedial tutorial program with one child who had been diagnosed as a disabled reader. The student had been functioning as a slow learner in the classroom. More specifically, an attempt was made to verify or reject the hypothesis that improvement of the subject\u27s reading ability would result in an enhancement of his self-image. A second hypothesis was to determine if the regular classroom work would profit by this improved self-image
New Distribution Records of Ground Beetles From the North Central United States (Coleoptera: Carabidae)
We report 39 ground beetles new to five states in the upper midwestern United States. These species records include 19 new to Illinois (all but one from Lake County), 11 from Iowa, three from South Dakota, eight from Wisconsin, and two from Michigan. (Three species are new to more than one state). Enigmatically disjunct collections include the myrmecophile, Helluomorphoides nigripennis from western Illinois, known previously only from the Atlantic and Gulf coastal plain and piedmont, and Chlaenius amoenus, reported only from southeastern states and now from northeast Iowa
Energy Conversion Alternatives Study (ECAS), Westinghouse phase 1. Volume 5: Combined gas-steam turbine cycles
The energy conversion efficiency of gas-steam turbine cycles was investigated for selected combined cycle power plants. Results indicate that it is possible for combined cycle gas-steam turbine power plants to have efficiencies several point higher than conventional steam plants. Induction of low pressure steam into the steam turbine is shown to improve the plant efficiency. Post firing of the boiler of a high temperature combined cycle plant is found to increase net power but to worsen efficiency. A gas turbine pressure ratio of 12 to 1 was found to be close to optimum at all gas turbine inlet temperatures that were studied. The coal using combined cycle plant with an integrated low-Btu gasifier was calculated to have a plant efficiency of 43.6%, a capitalization of $497/kW, and a cost of electricity of 6.75 mills/MJ (24.3 mills/kwh). This combined cycle plant should be considered for base load power generation
Calibration choice, rate smoothing, and the pattern of tetrapod diversification according to the long nuclear gene RAG-1
This is an electronic version of an article published in Systematic Biology, 2007; 56 (4):543-563. Systematic Biology is available online at informaworld: http://www.informaworld.com/smpp/content~db=all?content=10.1080/10635150701477825A phylogeny of tetrapods is inferred from nearly complete sequences of the nuclear RAG-1 gene sampled across 88 taxa encompassing all major clades, analyzed via parsimony and Bayesian methods. The phylogeny provides support for Lissamphibia, Theria, Lepidosauria, a turtle-archosaur clade, as well as most traditionally accepted groupings. This tree allows simultaneous molecular clock dating for all tetrapod groups using a set of well-corroborated calibrations. Relaxed clock (PLRS) methods, using the amniote = 315 Mya (million years ago) calibration or a set of consistent calibrations, recovers reasonable divergence dates for most groups. However, the analysis systematically underestimates divergence dates within archosaurs. The bird-crocodile split, robustly documented in the fossil record as being around ∼ 245 Mya, is estimated at only ∼ 190 Mya, and dates for other divergences within archosaurs are similarly underestimated. Archosaurs, and particulary turtles have slow apparent rates possibly confounding rate modeling, and inclusion of calibrations within archosaurs (despite their high deviances) not only improves divergence estimates within archosaurs, but also across other groups. Notably, the monotreme-therian split (∼ 210 Mya) matches the fossil record; the squamate radiation (∼ 190 Mya) is younger than suggested by some recent molecular studies and inconsistent with identification of ∼ 220 and ∼ 165 Myo (million-year-old) fossils as acrodont iguanians and ∼ 95 Myo fossils colubroid snakes; the bird-lizard (reptile) split is considerably older than fossil estimates (≤ 285 Mya); and Sphenodon is a remarkable phylogenetic relic, being the sole survivor of a lineage more than a quarter of a billion years old. Comparison with other molecular clock studies of tetrapod divergences suggests that the common practice of enforcing most calibrations as minima, with a single liberal maximal constraint, will systematically overestimate divergence dates. Similarly, saturation of mitochondrial DNA sequences, and the resultant greater compression of basal branches means that using only external deep calibrations will also lead to inflated age estimates within the focal ingroup.Andrew F. Hugall; Ralph Foster; Michael S. Y. Le
- …