A method of design for spiral reinforced, eccentrically loaded, concrete columns

This thesis presents a method of designing spiral reinforced, eccentrically loaded, concrete columns on the basis of the 1957 American Association of State Highway Officials specifications. Equations from AASHO, in conjunction with equations derived in this thesis, are programmed for and solved by the IBM 650 digital computer. The data obtained from the computer is plotted such that, given the normal load and moment on a column, the minimum required area or reinforcing steel may be read directly from the graph. The derivation or equations, the computer program, and the graphs are included in the thesis --Introduction, page 1

Farm leases in Iowa

Farm tenancy in Iowa is a live question because already, a large percentage of the farms of the state are operated by tenants and because there has been a rapid increase in the number of farms rented from year to year. The opinion is quite generally held that one can tell a rented farm by its dilapidated buildings, poor crops and worn out land. It is also quite generally believed that there is something wrong with the existing system of. farm leases as a whole. The fact is that many of the best managed and most successful farms are operated by tenants and in general it may be stated that out of experience have come several methods of leasing which seem to provide for good farming and a fair division of returns between the land owner and tenant. These general facts were brought out in an investigation prompted by the general interest in farm tenancy and the rapid increase of rented farms operated by year to year tenants. Director C. F. Curtiss of the Iowa Agricultural Experiment station planned to undertake this investigation and secured the cooperation of the United States Department of Agriculture in an effort to get at the truth about farm tenancy and to determine what constitutes a satisfactory farm lease. In other words, the purpose of the investigation was to learn what the landlord and tenant each should furnish and what each should receive in a lease which calls for profitable farming and a fair division of the farm returns

X-ray Studies of Two Neutron Stars in 47 Tucanae: Toward Constraints on the Equation of State

We report spectral and variability analysis of two quiescent low mass X-ray binaries (X5 and X7, previously detected with the ROSAT HRI) in a Chandra ACIS-I observation of the globular cluster 47 Tuc. X5 demonstrates sharp eclipses with an 8.666+-0.01 hr period, as well as dips showing an increased N_H column. The thermal spectra of X5 and X7 are well-modeled by unmagnetized hydrogen atmospheres of hot neutron stars. No hard power law component is required. A possible edge or absorption feature is identified near 0.64 keV, perhaps an OV edge from a hot wind. Spectral fits imply that X7 is significantly more massive than the canonical 1.4 \Msun neutron star mass, with M>1.8 \Msun for a radius range of 9-14 km, while X5's spectrum is consistent with a neutron star of mass 1.4 \Msun for the same radius range. Alternatively, if much of the X-ray luminosity is due to continuing accretion onto the neutron star surface, the feature may be the 0.87 keV rest-frame absorption complex (O VIII & other metal lines) intrinsic to the neutron star atmosphere, and a mass of 1.4 \Msun for X7 may be allowed.Comment: 16 pages, 7 figures, accepted by Ap

Compressing Word Embeddings

Recent methods for learning vector space representations of words have succeeded in capturing fine-grained semantic and syntactic regularities using vector arithmetic. However, these vector space representations (created through large-scale text analysis) are typically stored verbatim, since their internal structure is opaque. Using word-analogy tests to monitor the level of detail stored in compressed re-representations of the same vector space, the trade-offs between the reduction in memory usage and expressiveness are investigated. A simple scheme is outlined that can reduce the memory footprint of a state-of-the-art embedding by a factor of 10, with only minimal impact on performance. Then, using the same `bit budget', a binary (approximate) factorisation of the same space is also explored, with the aim of creating an equivalent representation with better interpretability.Comment: 10 pages, 0 figures, submitted to ICONIP-2016. Previous experimental results were submitted to ICLR-2016, but the paper has been significantly updated, since a new experimental set-up worked much bette

The effect of treatment on pathogen virulence.

The optimal virulence of a pathogen is determined by a trade-off between maximizing the rate of transmission and maximizing the duration of infectivity. Treatment measures such as curative therapy and case isolation exert selective pressure by reducing the duration of infectivity, reducing the value of duration-increasing strategies to the pathogen and favoring pathogen strategies that maximize the rate of transmission. We extend the trade-off models of previous authors, and represents the reproduction number of the pathogen as a function of the transmissibility, host contact rate, disease-induced mortality, recovery rate, and treatment rate, each of which may be influenced by the virulence. We find that when virulence is subject to a transmissibility-mortality trade-off, treatment can lead to an increase in optimal virulence, but that in other scenarios (such as the activity-recovery trade-off) treatment decreases the optimal virulence. Paradoxically, when levels of treatment rise with pathogen virulence, increasing control efforts may raise predicted levels of optimal virulence. Thus we show that conflict can arise between the epidemiological benefits of treatment and the evolutionary risks of heightened virulence

Materials Recovery Facilities in the United States Virgin Islands: A Regional Facilities Location Model Study

Continental municipalities have derived many benefits from the economies of scale associated with a regional approach to facilities location and management planning. Centralized solid waste processing facilities is an example. Island communities, however, surrounded by miles of ocean, are constrained to a fragmented approach to the facilities location solution. This research was conducted to determine if the regional paradigm suggested in the literature is applicable to a set of island communities connected by an ocean transportation infrastructure. A linear programming (LP) model, constraints and data requirements were developed and applied to a network of islands. A series of hypothetical material recovery facilities (MRF) location scenarios were studied using actual and projected data obtained for the three-island territory of the U. S. Virgin Islands. In all cases, a significant reduction in capital construction expenditures was realized. For the selected data values in the research, transportation and operating costs increased as expected, but by a surprisingly small amount. This research concludes that the regional approach to economic and environmental facilities planning for island communities is valid. Future research involving larger systems of islands and stochastic processes is suggested

solveME: fast and reliable solution of nonlinear ME models.

BackgroundGenome-scale models of metabolism and macromolecular expression (ME) significantly expand the scope and predictive capabilities of constraint-based modeling. ME models present considerable computational challenges: they are much (>30 times) larger than corresponding metabolic reconstructions (M models), are multiscale, and growth maximization is a nonlinear programming (NLP) problem, mainly due to macromolecule dilution constraints.ResultsHere, we address these computational challenges. We develop a fast and numerically reliable solution method for growth maximization in ME models using a quad-precision NLP solver (Quad MINOS). Our method was up to 45 % faster than binary search for six significant digits in growth rate. We also develop a fast, quad-precision flux variability analysis that is accelerated (up to 60× speedup) via solver warm-starts. Finally, we employ the tools developed to investigate growth-coupled succinate overproduction, accounting for proteome constraints.ConclusionsJust as genome-scale metabolic reconstructions have become an invaluable tool for computational and systems biologists, we anticipate that these fast and numerically reliable ME solution methods will accelerate the wide-spread adoption of ME models for researchers in these fields

Ionization yields of fission fragments in gases

The present problem arises from a consideration of some of the experimental and theoretical results which were obtained previously, some of which will now be briefly mentioned. Fission fragment mass distributions which were derived from data obtained from double ionization chambers using argon plus carbon dioxide gases disagree with those obtained by means of radiochemical analysis of the fission products. Fission fragment velocity distributions which were also derived from double ionization chamber data disagree with those obtained from a direct measurement of velocities. Further, these double ionization chamber measurements of the total kinetic energy of fission give lower values than those estimated from calorimetric measurements. These disagreements are explained by assuming the W (average energy per ion pair) values of fission fragments stopped in an ionization chamber gas are of the order of 5 percent larger than those for alpha particles which were used as the basis to calculate fission energies. On the basis that fission fragments lost greater percentages of initial energy through elastic collisions and that recoil argon gas atoms had reduced ionization efficiencies, a theoretical calculation in terms of an ionization defect appeared to justify this viewpoint. The ionization defect. is thought to arise from energy transfer through elastic collisions and hence should be a function of the atomic mass of the gas