Causes of failure of airship shed

The causes of the collapse of airship shed, which was being taken down at Niediergorsdorf, are discussed. This shed, which was built of iron, was 184 m long, 28 m high, and 35 m wide. The demolition of the shed had been assigned to unskilled men who proceeded to remove certain key structural supports, leaving the structure in such a condition that relatively small eccentricities of the columns or spans or of lateral forces could easily have caused the columns or spans to break down. A small gust of wind would have perhaps sufficed to bring the building down. An analysis is also given of the suction effects on the roof of an air shed in Staaken. The damage to this shed, which occurred during a storm, was due to the fact that the shed had no opening in its top for equalizing the air pressure within and without. The location of the plates blown off the roof correspond to the point of greatest suction

Band structures of rare gas solids within the GW approximation

Band structures for solid rare gases (Ne, Ar) have been calculated using the GW approximation. All electron and pseudopotential ab initio calculations were performed using Gaussian orbital basis sets and the dependence of particle-hole gaps and electron affinities on basis set and treatment of core electrons is investigated. All electron GW calculations have a smaller particle-hole gap than pseudopotential GW calculations by up to 0.2 eV. Quasiparticle electron and hole excitation energies, valence band widths and electron affinities are generally in very good agreement with those derived from optical absorption and photoemission measurements.Comment: 7 pages 1 figur

An App for Third Party Beneficiaries

Every year, more than 100 reported court opinions consider the question of whether an outsider can sue for damages under a contract made by others-in part because the law is so ambiguous. While contract enforcement by a third party is controlled largely by the facts of the particular case, it also materially depends upon the relevant legal standards. At present, not just the standards, but also the reasons for these standards, are unclear. Eighty years ago, Lon Fuller, a professor teaching contracts at a then-Southern law school, and William Perdue, a student at that school, significantly clarified and improved decision making on damages issues in contract law by proposing a new vocabulary and analytical model. The senior author of this Article is a professor at a Southern law school, but he does not need an academic Lloyd Bentsen to tell him that he is no Lon Fuller, and the younger co-authors hold no William Perdue illusion, given that Mr. Perdue was the father-in-law of their law school dean. Nonetheless, we believe that the new vocabulary and analytical model we are proposing would clarify and improve decision-making on third party contract rights

Optical Properties of the Rubidium and Cesium Halides in the Extreme Ultraviolet

The absorption spectra of evaporated thin films of all rubidium and cesium halides in the 50- to 250-eV region are reported. In this range, transitions from the 3d shell of Rb+ and from the 4d and 4p shells of Cs+ can be seen, as well as some transitions from inner shells of the halogen ions. Besides the absorption fine structure near the threshold for inner-shell transitions, broad absorption structure is observed and explained as due to d→f continuum transitions. The number of effective electrons whose oscillator strength has been exhausted in our spectral region has been computed from the absorption data; it is particularly strong for materials containing either Cs or I. Differences in the spectra of materials with NaCl and with CsCl structure are discussed. The measurements were performed using the DESY electron synchrotron as a light source

Liquid—Vapor Equilibrium in the System Equilibrium Hydrogen—Helium

Liquid—vapor equilibrium‐phase compositions for the binary system 20.40° equilibrium hydrogen—helium have been determined for six isotherms in the range 20.40°—31.50°K and at pressures up to 500 psia. The vapor recirculation method of obtaining equilibrium was used in conjunction with a liquid‐hydrogen vapor‐pressure‐controlled cryostat. Analyses were made on a mass spectrograph. The results are presented in both tabular and graphical form, and comparisons with those reported previously for the system normal hydrogen—helium have also been made.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/71039/2/JCPSA6-41-8-2399-1.pd

Liquid—Vapor Equilibrium in the System Normal Hydrogen—Helium

Liquid—vapor equilibrium phase compositions for the binary system normal hydrogen—helium have been determined for 11 isotherms in the range 15.50°—32.50°K and at pressures up to 500 psia. The vapor recirculation method of obtaining equilibrium was used in conjunction with a liquid hydrogen vapor—pressure controlled cryostat. Analyses were made on a mass spectrograph. The results are presented in both tabular and graphical form, and the general behavior of the system discussed. An agreement with some previous investigations is demonstrated, and conflicts in existing data are resolved. Some problems of theoretical correlation of the data are discussed.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/71182/2/JCPSA6-40-5-1390-1.pd

Comparative analysis of 2D and 3D models of turbulent natural convection and thermal surface radiation in closed areas

Turbulent natural convection with surface thermal radiation in air-filled enclosures has been investigated. The equations of conservation of mass, momentum and energy are solved using both finite difference and control volume methods. It should be noted that the working medium is Newtonian and heat conducting fluid, where the Boussinesq approximation is valid. The walls are supposed to be gray, diffuse emitters and reflectors of radiation. The left and right surfaces of the enclosure are isothermal walls, while other surfaces are adiabatic walls. The considered fluid flow is turbulent. The main aim of the present research is to compare the heat transfer process in 2D and 3D enclosures. Detailed results including flow profiles, temperature fields, and average Nusselt numbers have been presented

Ab initio many-body calculation of excitons in solid Ne and Ar

Absorption spectra, exciton energy levels and wave functions for solid Ne and Ar have been calculated from first principles using many-body techniques. Electronic band structures of Ne and Ar were calculated using the GW approximation. Exciton states were calculated by diagonalizing an exciton Hamiltonian derived from the particle-hole Green function, whose equation of motion is the Bethe-Salpeter equation. Singlet and triplet exciton series up to n=5 for Ne and n=3 for Ar were obtained. Binding energies and longitudinal-transverse splittings of n=1 excitons are in excellent agreement with experiment. Plots of correlated electron-hole wave functions show that the electron-hole complex is delocalised over roughly 7 a.u. in solid Ar.Comment: 6 page

An App for Third Party Beneficiaries

Every year, more than 100 reported court opinions consider the question of whether an outsider can sue for damages under a contract made by others—in part because the law is so ambiguous. While contract enforcement by a third party is controlled largely by the facts of the particular case, it also materially depends upon the relevant legal standards. At present, not just the standards, but also the reasons for these standards, are unclear. Eighty years ago, Lon Fuller, a professor teaching contracts at a then-Southern law school, and William Perdue, a student at that school, significantly clarified and improved decision-making on damages issues in contract law by proposing a new vocabulary and analytical model. The senior author of this Article is a professor at a Southern law school, but he does not need an academic Lloyd Bentsen to tell him that he is “no Lon Fuller,” and the younger co-authors hold no “William Perdue illusion,” given that Mr. Perdue was the father-in-law of their law school dean. Nonetheless, we believe that the new vocabulary and analytical model we are proposing would clarify and improve decision-making on third party contract rights

Computer simulation of crystallization kinetics with non-Poisson distributed nuclei

The influence of non-uniform distribution of nuclei on crystallization kinetics of amorphous materials is investigated. This case cannot be described by the well-known Johnson-Mehl-Avrami (JMA) equation, which is only valid under the assumption of a spatially homogeneous nucleation probability. The results of computer simulations of crystallization kinetics with nuclei distributed according to a cluster and a hardcore distribution are compared with JMA kinetics. The effects of the different distributions on the so-called Avrami exponent $n$ are shown. Furthermore, we calculate the small-angle scattering curves of the simulated structures which can be used to distinguish experimentally between the three nucleation models under consideration.Comment: 14 pages including 7 postscript figures, uses epsf.sty and ioplppt.st