Investigation of the solidification, structure and properties of eutectic alloys including consideration of properties control Progress report

Solidification, structure, and properties of nickel and niobium eutectic alloy

Investigation of the solidification, structure and properties of eutectic alloys including consideration of properties control

Solidification structure and properties of eutetic alloy

Big Bang Nucleosynthesis and the Missing Hydrogen Mass in the Universe

It is proposed that when the era of the big-bang nucleosynthesis ended, almost all of the 75 percent of the observed total baryonic matter remained in the form of hydrogen and continued to exist in the form of protons and electrons. They are present today as baryonic dark matter in the form of intergalactic hydrogen plasma. To test our hypothesis we have investigated the effects of Thomson scattering by free electrons on the reported dimming of Type Ia supernovae. The quantitative results of our calculation suggest that the dimming of these supernovae, which are dimmer than expected and hence more distant than predicted by Hubble expansion, is a result of Thomson scattering without cosmic acceleration.Comment: A typographical error in equation (7) page 3 has been correcte

Effects of mean flow on duct mode optimum suppression rates

The nature of the solution to the convected acoustic wave equation and associated boundary conditions for rectangular ducts containing uniform mean flow is examined in terms of the complex mapping between the wall admittance and characteristic mode eigenvalues. It is shown that the Cremer optimum suppression criteria must be modified to account for the effects of flow below certain critical values of the nondimensional frequency parameter of duct height divided by sound wavelength. The implications of these results on the design of low frequency suppressors are considered

Preliminary Study of Advanced Turboprops for Low Energy Consumption

The fuel savings potential of advanced turboprops (operational about 1985) was calculated and compared with that of an advanced turbofan for use in an advanced subsonic transport. At the design point, altitude 10.67 km and Mach 0.80, turbine-inlet temperature was fixed at 1590 K while overall pressure ratio was varied from 25 to 50. The regenerative turboprop had a pressure ratio of only 10 and an 85 percent effective rotary heat exchanger. Variable camber propellers were used with an efficiency of 85 percent. The study indicated a fuel savings of 33 percent, a takeoff gross weight reduction of 15 percent, and a direct operating cost reduction of 18 percent was possible when turboprops were used instead of the reference turbofan at a range of 10 200 km. These reductions were 28, 11, and 14 percent, respectively, at a range of 5500 km. Increasing overall pressure ratio from 25 to 50 saved little fuel and slightly increased takeoff gross weight

Neutral and Cationic Bis-Chelate Monoorganosilicon(IV) Complexes of 1-Hydroxy-2-pyridinone

A series of spirocyclic monoorganosilicon compounds of the form RSi(OPO)2Cl [R = phenyl (1); p-tolyl (2); benzyl (3); Me (4); tBu (5); thexyl (6)] (OPO = 1-oxo-2-pyridinone) was synthesized and characterized by 1H , 13C, and 29Si NMR spectroscopy, X-ray crystallography, and elemental analysis. In the solid state, complexes 1, 2, and 3 are neutral and possess cis-OPO ligands in an octahedral arrangement, and complexes 4, 5, and 6 are cationic and possess effectively trans­-OPO ligands in nearly ideal square pyramidal geometries along the Berry-pseudorotation coordinate. In 4-6, chloride dissociation is attributed to the additive effect of multiple intermolecular C—H∙∙∙Cl interactions in their crystals. In DMSO-d6 solution, compounds 1-6 form cationic hexacoordinate DMSO adducts with trans-OPO ligands, all of which undergo dynamic isomerization with energy barriers of ~18-19 kcal/mol. Compounds with better leaving groups, (p-tolyl)Si(OPO)2X [X = I (7); X = triflate (8)], exhibit identical solution NMR spectra as 2, supporting anion dissociation in each. The fluoride derivatives RSi(OPO)2F [R = benzyl (9); Me (10)] exhibit hexacoordinate geometries with cis­-OPO ligands in the solid state and exhibit dynamic isomerization in solution. Overall, these studies indicate, in both the solid and solution states, that the trans-OPO ligand arrangement is favored when anions are dissociated and a cis­-OPO ligand arrangement when anions are coordinated

Pharmacological and non-pharmacological treatments for the Neonatal Abstinence Syndrome (NAS).

Neonatal abstinence syndrome is defined by signs and symptoms of withdrawal that infants develop after intrauterine maternal drug exposure. All infants with documented in utero opioid exposure, or a high pre-test probability of exposure should have monitoring with a standard assessment instrument such as a Finnegan Score. A Finnegan score of \u3e8 is suggestive of opioid exposure, even in the absence of declared use during pregnancy. At least half of infants in most locales can be treated without the use of pharmacologic means. For this reason, symptom scores will drive the decision for pharmacologic therapy. Nevertheless, all infants, regardless of initial manifestations, should be first be managed with non-pharmacologic approaches which in turn, should not be considered as the sole alternative to drug therapy, but rather, as the base upon which all patients are treated. Those who continue to have symptoms despite supportive care should be pharmacologically treated, which in the most severe cases, is life-saving

Neonatal abstinence syndrome: Pharmacologic strategies for the mother and infant.

Opioid use in pregnancy has increased dramatically over the past decade. Since prenatal opioid use is associated with numerous obstetrical and neonatal complications, this now has become a major public health problem. In particular, in utero opioid exposure can result in neonatal abstinence syndrome (NAS) which is a serious condition characterized by central nervous system hyperirritability and autonomic nervous system dysfunction. The present review seeks to define current practices regarding the approach to the pregnant mother and neonate with prenatal opiate exposure. Although the cornerstone of prenatal management of opioid dependence is opioid maintenance therapy, the ideal agent has yet to be definitively established. Pharmacologic management of NAS is also highly variable and may include an opioid, barbiturate, and/or α-agonist. Genetic factors appear to be associated with the incidence and severity of NAS. Establishing pharmacogenetic risk factors for the development of NAS has the potential for creating opportunities for personalized genomic medicine and novel, individualized therapeutic interventions

Van der Waals Correction to Nuclear Fusion by Mechanical Adiabatic Compression of a Dense Plasma

We consider fusion processes initiated by the rapid adiabatic compression by a piston of a deuterium plasma contained in a well‐insulated chamber. To exploit the n2 factor in the fusion reaction rate, we consider one mole of deuterium which, at ambient temperature and pressure, provides a particle density of ~ 10^19 cm^‐3. The reaction rate is enhanced by the application of magnetic and electric fields to reduce the number of degrees of freedom of the gas, thereby lowering its heat capacity and producing a higher temperature increase for a given energy input. Previous studies have shown that the combination of adiabatic operation, high particle density and reduced degrees of freedom can result in appreciable fusion rates at temperatures lower than those in magnetic confinement experiments. Prior work treated the deuterium gas as an ideal gas while the present work incorporates the corrections of a van der Waals gas. Both primary D-D reactions and secondary D-T reactions are considered. Conditions of energy-break-even and excess energy release were found at temperatures of the order of 10^6 K