Joule—Thomson Effect on Gaseous Helium

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/71138/2/JCPSA6-42-8-2977-1.pd

A Unifying Theory for SIDS

The Sudden Infant Death Syndrome (SIDS) has four distinctive characteristics that must be explained by any theory proposed for it. (1) A characteristic male fraction of approximately 0.61 for all postneonatal SIDS in the US; (2) a distinctive lognormal-type age distribution arising from zero at birth, mode at about 2 months, median at about 3 months, and an exponential decrease with age going towards zero beyond one year; (3) a marked decrease in SIDS rate from the discovery that changing the recommended infant sleep position from prone to supine reduced the rate of SIDS, but it did not change the form of the age or gender distributions cited above; (4) a seasonal variation, maximal in winter and minimal in summer, that implies subsets of SIDS displaying evidence of seasonal low-grade respiratory infection and nonseasonal neurological prematurity. A quadruple-risk model is presented that fits these conditions but requires confirmatory testing by finding a dominant X-linked allele protective against cerebral anoxia that is missing in SIDS

Enthalpy determinations on the helium-nitrogen system

Experimental isobaric heat capacity and differential latent heat measurements have been made on the helium-nitrogen system. Compositions studied were nominal 5, 25, 50, and 100% helium in nitrogen over the range 0 to 2,000 lb./sq.in.abs. and −250° to 50°F. These data, combined with the previously reported work on nitrogen and the Joule-Thomson coefficients of Roebuck, are used to construct the complete pressure-enthalpy-composition network over the investigated limits of pressure and temperature. The enthalpies obtained from experimental heat capacity and Joule-Thomson data are compared with enthalpies computed from PVT data. The changes of phase determined by differential latent heat measurements are compared with literature vapor-liquid equilibrium data. This information is used to prepare pressure-enthalpy diagrams for all the mixtures investigated. A three-dimensional representation of the data on a pressure-enthalpy-composition diagram is presented. Constructions are outlined from which heats of mixing and partial molal enthalpies can be obtained. The thermodynamic network developed is believed accurate within 1% and should be of use to those concerned with low-temperature separation of helium from nitrogen.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/37341/1/690120126_ftp.pd

Factors associated with self-reported, pesticide-related visits to health care providers in the agricultural health study

To investigate factors associated with pesticide-related visits to health care providers (i.e., doctor or hospital visits), responses to self-administered questionnaires received from 35,879 licensed restricted-use pesticide applicators participating in the Agricultural Health Study were analyzed. (In Iowa, applicators are actually certified, whereas in North Carolina they are licensed; for ease of reference, the term license will be used for both states in this paper.) The cohort reported a total of more than 10.9 million pesticide-application days. These applications were associated with one or more pesticide-related health care visits by 2,214 applicators (7.0% of the applicator cohort for whom health care visit data were available). The odds of a pesticide-related health care visit were increased for commercial applicators compared to private applicators [odds ratio ( 0 R = 1. 77; 95% confidence interval (CI), 1.52-2.06) and for applicators who used insecticides 70 times or more in their lifetime compared to those who used insecticides less frequently (OR = 1.43; CI, 1.26-1.63). After adjusting for the number of applications in a logistic regression model, significantly higher odds of health care visits were observed among North Carolina applicators compared to Iowa applicators (OR= 1.35; CI, 1.17- 1.52), among applicators who mixed their own pesticides (OR = 1.65; CI, 1.22- 2.23), and among applicators who personally repaired their pesticide application equipment at least once per year (OR= 1.12; Cl, 1.06-1.25). Significantly lower odds were found among female versus male applicators (OR = 0.68; Cl, 0.46-0.99) and among applicators who graduated from high school versus those who did not (OR= 0.82; CI, 0.71-0.94 for high school graduates and OR = 0.79; CI, 0.68-0.91 for those with at least some college). Several methods of pesticide application to crops, seed, or stored grain were also associated with significantly elevated odds ratios of health care visits. These observations suggest that several steps can be taken to reduce the number of health care visits resulting from occupational exposure to pesticides. The implications of this pattern of pesticide-related health care visits may have etiologic implications for cancer and other chronic diseases

Thermodynamic Properties Of The Helium - Nitrogen System At Low Temperatures And High Pressures.

PhDChemical engineeringUniversity of Michigan, Horace H. Rackham School of Graduate Studieshttp://deepblue.lib.umich.edu/bitstream/2027.42/183867/2/6505344.pd

Centro de artes escénicas en el Lazareto (S. C. de Tenerife) [Hojas Resumen]

Centro de artes escénicas en el Lazaret