Structural optimization incorporating centrifugal and Coriolis effects

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/76768/1/AIAA-1989-1310-955.pd

Structural optimization including centrifugal effects

This paper investigates the effects of centrifugal forces on the frequencies of a rotating system and then provides an optimal redesign process. The rotational effects have a profound influence on the eigenfrequencies and are important in optimal structural redesign where the frequencies must be adjusted. The optimal redesign is done by deriving nonlinear inverse perturbation equations for the problem. Structural changes typically meet the frequency goals to within three percent.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/29489/1/0000575.pd

Structural optimization incorporating centrifugal and Coriolis effects

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/76888/1/AIAA-10798-921.pd

The Mount Perkins block, northwestern Arizona: An exposed cross section of an evolving, preextensional to synextensional magmatic system

This is the published version. Reuse is subject to Society of Exploration Geophysicists terms of use and conditions.The steeply tilted Mount Perkins block, northwestern Arizona, exposes a cross section of a magmatic system that evolved through the onset of regional extension. New 40Ar/39Ar ages of variably tilted (0–90°) volcanic strata bracket extension between 15.7 and 11.3 Ma. Preextensional intrusive activity included emplacement of a composite Miocene laccolith and stock, trachydacite dome complex, and east striking rhyolite dikes. Related volcanic activity produced an ∼18–16 Ma stratovolcano, cored by trachydacite domes and flanked by trachydacite-trachyandesite flows, and ∼16 Ma rhyolite flows. Similar compositions indicate a genetic link between the stratovolcano and granodioritic phase of the laccolith. Magmatic activity synchronous with early regional extension (15.7–14.5 Ma) generated a thick, felsic volcanic sequence, a swarm of northerly striking subvertical rhyolite dikes, and rhyolite domes. Field relations and compositions indicate that the dike swarm and felsic volcanic sequence are cogenetic. Modes of magma emplacement changed during the onset of extension from subhorizontal sheets, east striking dikes, and stocks to northerly striking, subvertical dike swarms, as the regional stress field shifted from nearly isotropic to decidedly anisotropic with an east-west trending, horizontal least principal stress. Preextensional trachydacitic and preextensional to synextensional rhyolitic magmas were part of an evolving system, which involved the ponding of mantle-derived basaltic magmas and ensuing crustal melting and assimilation at progressively shallower levels. Major extension halted this system by generating abundant pathways to the surface (fractures), which flushed out preexisting crustal melts and hybrid magmas. Remaining silicic melts were quenched by rapid, upper crustal cooling induced by tectonic denudation. These processes facilitated eruption of mafic magmas. Accordingly, silicic magmatism at Mount Perkins ended abruptly during peak extension ∼14.5 Ma and gave way to mafic magmatism, which continued until extension ceased

Structure Learning in Human Sequential Decision-Making

Studies of sequential decision-making in humans frequently find suboptimal performance relative to an ideal actor that has perfect knowledge of the model of how rewards and events are generated in the environment. Rather than being suboptimal, we argue that the learning problem humans face is more complex, in that it also involves learning the structure of reward generation in the environment. We formulate the problem of structure learning in sequential decision tasks using Bayesian reinforcement learning, and show that learning the generative model for rewards qualitatively changes the behavior of an optimal learning agent. To test whether people exhibit structure learning, we performed experiments involving a mixture of one-armed and two-armed bandit reward models, where structure learning produces many of the qualitative behaviors deemed suboptimal in previous studies. Our results demonstrate humans can perform structure learning in a near-optimal manner

Supramolecular approach to new inkjet printing inks

Electronically complementary, low molecular weight polymers that self-assemble through tunable π−π stacking interactions to form extended supramolecular polymer networks have been developed for inkjet printing applications and successfully deposited using three different printing techniques. Sequential overprinting of the complementary components results in supramolecular network formation through complexation of π-electron rich pyrenyl or perylenyl chain-ends in one component with π-electron deficient naphthalene diimide residues in a chain-folding polyimide. The complementary π−π stacked polymer blends generate strongly colored materials as a result of charge-transfer absorption bands in the visible spectrum, potentially negating the need for pigments or dyes in the ink formulation. Indeed, the final color of the deposited material can be tailored by varying the end-groups of the π-electron rich polymer component. Piezoelectric printing techniques were employed in a proof of concept study to allow characterization of the materials deposited, and a thermal inkjet printer adapted with imaging software enabled in situ analysis of the ink drops as they formed and of their physical properties. Finally, continuous inkjet printing allowed greater volumes of material to be deposited, on a variety of different substrate surfaces, and demonstrated the utility and versatility of this novel type of ink for industrial applications

Means versus ends in opaque institutional fields: Trading off compliance and achievement in sustainability standard adoption

__Abstract__ The long-standing discussion on decoupling has recently moved from adopters not implementing the agreed-upon policies to compliant adopters not achieving the goals intended by institutional entrepreneurs. This “means-ends decoupling” prevails especially in highly opaque fields, where practices, causality, and performance are hard to understand and chart. I conceptualize the conditions under which the adoption of institutions in relatively opaque fields leads to the achievement of the envisaged goals. Voluntary sustainability standards governing socioenvironmental issues illustrate these arguments. I argue that the lack of field transparency drives institutional entrepreneurs to create and maintain concrete and uniform rules, apply strong incentives, and disseminate “best practices” to ensure substantive adopter compliance. However, such rigid institutions are ill-equipped to deal with the causal complexity and practice multiplicity underlying opacity while they smother adopter agency. The ensuing tension between substantive compliance and goal achievement leads to an inherent trade-off: institutional entrepreneurs who remedy the policy-practice decoupling may enhance the disparity between means and ends, and vice versa. While sustainability standards and other institutions in highly opaque fields can, therefore, not fully achieve the envisaged goals, the trade-off can be reduced through systemically designed institutions that promote goal internalization and contain niche institutions

Vampires in the village Žrnovo on the island of Korčula: following an archival document from the 18th century

Središnja tema rada usmjerena je na raščlambu spisa pohranjenog u Državnom arhivu u Mlecima (fond: Capi del Consiglio de’ Dieci: Lettere di Rettori e di altre cariche) koji se odnosi na događaj iz 1748. godine u korčulanskom selu Žrnovo, kada su mještani – vjerujući da su se pojavili vampiri – oskvrnuli nekoliko mjesnih grobova. U radu se podrobno iznose osnovni podaci iz spisa te rečeni događaj analizira u širem društvenom kontekstu i prate se lokalna vjerovanja.The main interest of this essay is the analysis of the document from the State Archive in Venice (file: Capi del Consiglio de’ Dieci: Lettere di Rettori e di altre cariche) which is connected with the episode from 1748 when the inhabitants of the village Žrnove on the island of Korčula in Croatia opened tombs on the local cemetery in the fear of the vampires treating. This essay try to show some social circumstances connected with this event as well as a local vernacular tradition concerning superstitions