Stability of structural rings under uniformly distributed radial loads

Energy method analysis establishes parameters governing stability of circular rings acted upon by constant, uniformly distributed loads. Energy method is used so that nonlinear behavior of structure before buckling can be accounted for. Method affords conceptually superior basis for analyzing the axisymmetric deviation mode

SOME EXACT SOLUTIONS OF THE PROBLEM OF AXISYMMETRIC BENDING OF THIN SPHERICAL SHELLS

Exact solution of axisymmetrical bending equations for thin, spherical shells expressed as power serie

Axisymmetric thermal stresses in sandwich shells of revolution with application to shallow, spherical shells

Axisymmetric thermal stresses in sandwich shells of revolution with application to shallow spherical shell

The stability of circular rings under a uniformly distributed radial load Technical report

Circular ring stability analysis under uniformly distributed radial loa

CO on Ru(001): Formation and dissolution of islands of CO at low coverages

The present paper deals with the benefits and difficulties of using ion scattering spectroscopy as a spectrometric technique

Performance of PTFE-lined composite journal bearings

Plain cylindrical journal bearings consisting of aramid fiber reinforced epoxy outer shells and glass fiber reinforced PTFE lubricating liners were evaluated. All materials in these bearings are electrically nonconductive; thus eliminating the problem of galvanic corrosion sometimes encountered with metal bearings installed in dissimilar metal mountings. Friction and wear characteristics were determined for loads, temperatures, and oscillating conditions that are typical of current airframe bearing applications. Friction and wear characteristics were found to be compatible with most airframe bearing requirements from -23 C to 121 C. Contamination with MIL H-5606 hydraulic fluid increased wear of the PTFE liners at 121 C, but did not affect the structural integrity of the aramid/epoxy composite

Parasitism of \u3ci\u3ePlathypena Scabra\u3c/i\u3e (Lepidoptera: Noctuidae) by \u3ci\u3eSinophorus Teratis\u3c/i\u3e (Hymenoptera: Ichneumonidae)

(excerpt) A study was conducted at the Ecology Research Center, Miami University, Butler County, Ohio, during the summer of 1990 to examine the effects of strip intercropping sorghum and soybean on the occurrence of parasitoids and incidence of disease in larvae ofthe green cloverworm, Plathypena scabra (F.) (Lepidoptera: Noctuidae), a sporadic pest of soybeans. The details of the experimental design and results are reported elsewhere (Williams et al. 1995)

Effects of 3-d and 4-d-transition metal substitutional impurities on the electronic properties of CrO2

We present first-principles based density functional theory calculations of the electronic and magnetic structure of CrO2 with 3d (Ti through Cu) and 4d (Zr through Ag) substitutional impurities. We find that the half-metallicity of CrO2 remains intact for all of the calculated substitutions. We also observe two periodic trends as a function of the number of valence electrons: if the substituted atom has six or fewer valence electrons (Ti-Cr or Zr-Mo), the number of down spin electrons associated with the impurity ion is zero, resulting in ferromagnetic (FM) alignment of the impurity magnetic moment with the magnetization of the CrO2 host. For substituent atoms with eight to ten (Fe-Ni or Ru-Pd with the exception of Ni), the number of down spin electrons contributed by the impurity ion remains fixed at three as the number contributed to the majority increases from one to three resulting in antiferromagnetic (AFM) alignment between impurity moment and host magnetization. The origin of this variation is the grouping of the impurity states into 3 states with approximate "t2g" symmetry and 2 states with approximate "eg" symmetry. Ni is an exception to the rule because a Jahn-Teller-like distortion causes a splitting of the Ni eg states. For Mn and Tc, which have 8 valence electrons, the zero down spin and 3 down spin configurations are very close in energy. For Cu and Ag atoms, which have 11 valence electrons, the energy is minimized when the substituent ion contributes 5 Abstract down-spin electrons. We find that the interatomic exchange interactions are reduced for all substitutions except for the case of Fe for which a modest enhancement is calculated for interactions along certain crystallographic directions.Comment: 26 pages, 10 figures, 2 table