On the stability of the generalized, finite deformation correspondence model of peridynamics

A class of peridynamic material models known as constitutive correspondence models provide a bridge between classical continuum mechanics and peridynamics. These models are useful because they allow well-established local constitutive theories to be used within the nonlocal framework of peridynamics. A recent finite deformation correspondence theory (Foster and Xu, 2018) was developed and reported to improve stability properties of the original correspondence model (Silling et al., 2007). This paper presents a stability analysis that indicates the reported advantages of the new theory were overestimated. Homogeneous deformations are analyzed and shown to exibit unstable material behavior at the continuum level. Additionally, the effects of a particle discretization on the stability of the model are reported. Numerical examples demonstrate the large errors induced by the unstable behavior. Stabilization strategies and practical applications of the new finite deformation model are discussed

Noise of the Harrier in vertical landing and takeoff

The noise of the Harrier AV8C aircraft in vertical takeoff and landing was measured 100 feet to the side of the aircraft where jet noise dominates. The noise levels were quite high - up to 125 dB overall sound level at 100 feet. The increased noise due to jet impingement on the ground is presented as a function of jet height to diameter ratio. The impingement noise with the aircraft close to the ground was 14 to 17 dB greater than noise from a free jet. Results are compared with small-scale jet impingement data acquired elsewhere. The agreement between small-scale and full-scale noise increase in ground effect is fairly good except with the jet close to the ground. It is proposed that differences in the jet Reynolds numbers and the resultant character of the jets may be partially responsible for the disparity in the full-scale and small-scale jet impingement noise. The difference between single-jet impingement and multiple-jet impingement may also have been responsible for the small-scale and full-scale disagreement

The Last Shall Be First: Northern Methodists in Reconstruction Jacksonville

During Reconstruction, many northern men and women contributed to Florida’s social, political, and economic life. Their efforts— and those of the northern institutions and organizations that supported them— provided immediate assistance to the needy and resulted, as well, in the establishment of churches, schools, and other institutions that endured the test of time. Nonetheless, most Floridians have gained only a one-dimensional understanding of the contributions of Northerners during Reconstruction, usually through the highly critical eyes of historians such as William Watson Davis. Of them, Davis, a disciple of Columbia University’s Dunning School of Reconstruction historiography, wrote: “The failure of the Republican government was . . . incident to the operations of a lot of self-seeking, reckless, shrewd, and grafting politicians, who were in local politics for all they could squeeze out of it, who controlled, by fair means or foul, the ignorant and often vicious negro majorities and therefore controlled the government and therefore the public purse-strings.“

Swaim Family Papers: Civil War Reports and Letters of Recommendation for a Carpetbagger

Yankee families became involved in Florida during the Civil War and in the Reconstruction. For example, the family of the American merchant John Jacob Astor owned a tiny railroad that connected Tocoi on the St.Johns River with St. Augustine; they later sold it to New York industrialist and founder of Standard Oil, Henry Flagler. The family of New York-born writer Henry James invested in a cotton plantation in Alachua County. Best known perhaps is Harriet Beecher Stowe\u27s orange grove in Mandarin where she and her family wintered for seventeen years. The origins of these ventures remained largely unexplored as Florida documents were returned to the North, having never been seen by historians in this state. Now, as Northern libraries, historical societies, and archives place descriptions of their holdings online, it is possible to locate materials and collections that have been unexamined by Florida researchers. In 2012, Harriet Beecher Stowe\u27s first published articles about Florida were discovered by finding issues of a Boston newspaper that scholars believed no longer existed. In another example, the availability of online resources revealed the papers of John Swaim, a founder of modern Florida. The purpose of this article is to share something of the range and diversity of their content

Aid Societies Were Not Alike: Northern Teachers in Post-Civil War Florida

Northern teachers in the South during the Civil War and Reconstruction have been the subject of various studies.1 This literature emphasizes the origins and development of the aid societies that sponsored the teachers, and it focuses upon major figures who shaped educational policy. At the same time, little attention details the activities of early northern teachers in Florida within the context of developments in other places. Florida’s experience varies from other parts of the South, and it offers, by contrast, a fresh perspective on the regional experience. Ansel Eddy Kinne’s career provides an opportunity for understanding aid societies. From early 1864 to late 1866 he was superintendent of schools in Florida for one such organization, the National Freedmen’s Relief Association of New York (NFRA)

Development of a preliminary high-angle-of-attack nose-down pitch control requirement for high-performance aircraft

The requirements for high-angle-of-attack nose-down pitch control for advanced high-performance aircraft are discussed. Background information on fundamental factors that influence and, to a large extent, determine the high angle-of-attack nose-down control requirement is briefly reviewed. Guidelines currently proposed by other sources which attempt to define these requirements are discussed. A requirement based on NASA analysis of the characteristics of existing relaxed static stability (RSS) aircraft is presented. This analysis could provide the basis for a preliminary design guide

The clinical pharmacology of intranasal l-methamphetamine.

BackgroundWe studied the pharmacology of l-methamphetamine, the less abused isomer, when used as a nasal decongestant.Methods12 subjects self-administered l-methamphetamine from a nonprescription inhaler at the recommended dose (16 inhalations over 6 hours) then at 2 and 4 (32 and 64 inhalations) times this dose. In a separate session intravenous phenylephrine (200 microg) and l-methamphetamine (5 mg) were given to define alpha agonist pharmacology and bioavailability. Physiological, cardiovascular, pharmacokinetic, and subjective effects were measured.ResultsPlasma l-methamphetamine levels were often below the level of quantification so bioavailability was estimated by comparing urinary excretion of the intravenous and inhaled doses, yielding delivered dose estimates of 74.0 +/- 56.1, 124.7 +/- 106.6, and 268.1 +/- 220.5 microg for ascending exposures (mean 4.2 +/- 3.3 microg/inhalation). Physiological changes were minimal and not dose-dependent. Small decreases in stroke volume and cardiac output suggesting mild cardiodepression were seen.ConclusionInhaled l-methamphetamine delivered from a non-prescription product produced minimal effects but may be a cardiodepressant

Monitoring Greater Sage Grouse Populations and Habitat Use in the Southeast Montana Sage-Grouse Core Area

Sage grouse (Centrocercus urophasianus) core areas support Montana’s highest densities of sage grouse, and are deemed vitally important to sage grouse conservation long term. The Southeast Montana Sage Grouse Core Area (SEMT SGCA) consists of large expanses of intact sagebrush-steppe habitat and is important for connectivity among populations in Montana, South Dakota and Wyoming. Relatively little development has occurred in the area, but there is potential for energy development to have large-scale impacts on the area in the near future. Little was known about sage-grouse use of the area during critical periods outside of the breeding season or factors underlying local sage-grouse population dynamics. Therefore, we radio collared 94 sage grouse hens between 2009-2011 to quantify movements, habitat use, and population vital rates. Overall, hen locations tended to be within the SEMT SGCA during spring-summer and expanded to adjacent areas of Wyoming and South Dakota during winter. Wide annual fluctuations in weather conditions drove annual variation in population demographic rates, habitat conditions, and habitat use. Apparent nest success (34-68%) and average chick production per hen that began the breeding season (0.72-1.12 chicks/hen) varied among years with extreme to mild weather. Annual hen survival varied from a low of 46 percent under extreme winter conditions to > 60 percent under milder weather. Vegetation characteristics at nest, brood-rearing, and winter locations will be presented. Results from this project will aid in land use planning, prioritization of conservation efforts, and provide information to assess the effects of future land use change. The project is conducted by MFWP and funded by the BLM