Computer controlled X-ray spectrometeric analysis of geological materials

Digital computer controlled X ray fluorescent spectroscopy of geological material

Rotatable mass for a flywheel

An improved rotable mass for a flywheel characterized by a plurality of coaxially aligned, contiguous disks mounted on a spin shaft is presented. Each disk of the plurality is formed by a plurality of woven fibers disposed in a plane transversely related to an axis of rotation with the fibers of alternate disks being continuous throughout their length. The mid-portion of the fibers of the remaining disks of the plurality is removed for defining annular voids concentrically related to the spin shaft

Method of manufacture of bonded fiber flywheel

Layers of fiberglass cloth, generally forming a circular mass, are prestressed by rotation during the curing of epoxy which surrounds and thereby couples together fibers and layers of the cloth

Reanimating Ghost Editions, Reorienting the Early American Novel

What are the origins of the American novel? Does it begin with the imagination, when Europeans first began dreaming of life in the New World?1 Does it begin with Daniel Defoe’s adventurers, Robinson Crusoe and Moll Flanders, and their literary progeny? Or does the novel need a material presence in the soil of the New World? Does it begin in 1789, with William Hill Brown’s The Power of Sympathy?—which Isaiah Thomas, with shrewd prescience, marketed as the “first American novel.” Or does it begin even earlier, in 1742, with Benjamin Franklin’s first American edition of Samuel Richardson’s sentimental novel Pamela, published at his shop in Philadelphia? These are all arguable inception points for American fiction, grounded in particular kinds of historicist practices. But what if what we think we know about the material history of the novel in British America is wrong—or at least more complicated? What if we were able to push back by five decades the date of the first novel published in the American colonies and locate that first novel publication not in relatively liberal Pennsylvania, but at the height, and in the heart, of conservative Puritan Massachusetts? If the first novel published in the colonies was not a sentimental story about middling kinds of white people, as were Pamela and The Power of Sympathy, but rather a story about race, sex, violence, slavery, and colonialism, how would those facts change the stories we tell about the novel and early America

A robust approach to model densification and crack formation in powder compaction processes

This paper deals with the question of how to efficiently integrate a constitutive model that describes the densification of powders and the potential formation of cracks in Powder Metallurgy (P/M) cold compaction processes. The analyzed model is a large strain, elastoplastic model of the Drucker–Prager/Cap type, refined to cover also the prediction of crack formation, and featuring non-conventional elements such as a density-dependent Von Mises yield surface; a parabolic plastic potential function for the Drucker–Prager envelope; and a softening law whose softening modulus is dependent on the level of densification. The employed integration procedure is a non-conventional hybrid or IMPLicit–EXplicit (IMPL-EX) scheme, whose essence is to solve explicitly for some variables and implicitly for others, with the peculiarity of the ‘explicit’ variables being but extrapolated values of the same quantities computed, at previous time steps, by means of a fully implicit scheme. The return-mapping equations stemming from this implicit scheme are solved using an unconditionally convergent, fractional step method-based iterative procedure. The performance of the IMPL-EX integration algorithm is critically assessed in two different situations: the densification of a cylindrical specimen, and the fracture process in a diametral compression test. Results obtained show conclusively that the proposed hybrid integration strategy offers an efficient solution to the trade-off between robustness and computational time requirement

In-depth characterization of genome-scale network reconstructions for the in vitro synthesis in cell-free systems

Cell‐free systems containing multiple enzymes are becoming an increasingly interesting tool for one‐pot syntheses of biochemical compounds. To extensively explore the enormous wealth of enzymes in the biological space, we present methods for assembling and curing data from databases to apply them for the prediction of pathway candidates for directed enzymatic synthesis. We use Kyoto Encyclopedia of Genes and Genomes to establish single organism models and a pan‐organism model that is combining the available data from all organisms listed there. We introduce a filtering scheme to remove data that are not suitable, for example, generic metabolites and general reactions. In addition, a valid stoichiometry of reactions is required for acceptance. The networks created are analyzed by graph theoretical methods to identify a set of metabolites that are potentially reachable from a defined set of starting metabolites. Thus, metabolites not connected to such starting metabolites cannot be produced unless new starting metabolites or reactions are introduced. The network models also comprise stoichiometric and thermodynamic data that allow the definition of constraints to identify potential pathways. The resulting data can be directly applied using existing or future pathway finding tools

On the contact domain method: a comparison of penalty and Lagrange multiplier implementations

This work focuses on the assessment of the relative performance of the so-called contact domain method, using either the Lagrange multiplier or the penalty strategies. The mathematical formulation of the contact domain method and the imposition of the contact constraints using a stabilized Lagrange multiplier method are taken from the seminal work (as cited later), whereas the penalty based implementation is firstly described here. Although both methods result into equivalent formulations, except for the difference in the constraint imposition strategy, in the Lagrange multiplier method the constraints are enforced using a stabilized formulation based on an interior penalty method, which results into a different estimation of the contact forces compared to the penalty method. Several numerical examples are solved to assess certain numerical intricacies of the two implementations. The results show that both methods perform similarly as one increases the value of the penalty parameter or decreases the value of the stabilization factor (in case of the Lagrange multiplier method). However there seems to exist a clear advantage in using the Lagrange multiplier based strategy in a few critical situations, where the penalty method fails to produce convincing results due to excessive penetration