Churchburners and Irish: A study of the Philadelphia Riots of May and July, 1844

The 1840\u27s witnessed the emergence of Philadelphia as a big city from the old provincial town. These changes raised political-legal, economic, ethnic and religious problems which interacted to form the background of one of the most violent outbreaks of rioting in the early history of this country

Dip-coating of suspensions

Withdrawing a plate from a suspension leads to the entrainment of a coating layer of fluid and particles on the solid surface. In this article, we study the Landau-Levich problem in the case of a suspension of non-Brownian particles at moderate volume fraction $10\% < \phi < 41\%$. We observe different regimes depending on the withdrawal velocity $U$, the volume fraction of the suspension $\phi$, and the diameter of the particles $2\,a$. Our results exhibit three coating regimes. (i) At small enough capillary number $Ca$, no particles are entrained, and only a liquid film coats the plate. (ii) At large capillary number, we observe that the thickness of the entrained film of suspension is captured by the Landau-Levich law using the effective viscosity of the suspension $\eta(\phi)$. (iii) At intermediate capillary numbers, the situation becomes more complicated with a heterogeneous coating on the substrate. We rationalize our experimental findings by providing the domain of existence of these three regimes as a function of the fluid and particles properties

Economic Analysis of Simulation Selection Problems

Ranking and selection procedures are standard methods for selecting the best of a finite number of simulated design alternatives based on a desired level of statistical evidence for correct selection. But the link between statistical significance and financial significance is indirect, and there has been little or no research into it. This paper presents a new approach to the simulation selection problem, one that maximizes the expected net present value of decisions made when using stochastic simulation. We provide a framework for answering these managerial questions: When does a proposed system design, whose performance is unknown, merit the time and money needed to develop a simulation to infer its performance? For how long should the simulation analysis continue before a design is approved or rejected? We frame the simulation selection problem as a “stoppable” version of a Bayesian bandit problem that treats the ability to simulate as a real option prior to project implementation. For a single proposed system, we solve a free boundary problem for a heat equation that approximates the solution to a dynamic program that finds optimal simulation project stopping times and that answers the managerial questions. For multiple proposed systems, we extend previous Bayesian selection procedures to account for discounting and simulation-tool development costs

Funding Scientific Knowledge: Selection, Disclosure and the Public-Private Portfolio

This paper examines argues that while two distinct perspectives characterize the foundations of the public funding of research – filling a selection gap and solving a disclosure problem – in fact both the selection choices of public funders and their criteria for disclosure and commercialization shape the level and type of funding for research and the disclosures that arise as a consequence. In making our argument, we begin by reviewing project selection criteria and policies towards disclosure and commercialization (including patent rights) made by major funding organizations, noting the great variation between these institutions. We then provide a model of how selection criteria and funding conditions imposed by funders interact with the preferences of scientists to shape those projects that accept public funds and the overall level of openness in research. Our analysis reveals complex and unexpected relationships between public funding, private funding, and public disclosure of research. We show, for example, that funding choices made by public agencies can lead to unintended, paradoxical effects, providing short-term openness while stifling longer-term innovation. Implications for empirical evaluation and an agenda for future research are discussed.

Picking battles: The impact of trust assumptions on the elaboration of security requirements

This position paper describes work on trust assumptions in the con-text of security requirements. We show how trust assumptions can affect the scope of the analysis, derivation of security requirements, and in some cases how functionality is realized. An example shows how trust assumptions are used by a requirements engineer to help define and limit the scope of analysis and to document the decisions made during the process

Estimating the Operational Impact of Container Inspections at International Ports

A U.S. law mandating nonintrusive imaging and radiation detection for 100% of U.S.-bound containers at international ports has provoked widespread concern that the resulting congestion would hinder trade significantly. Using detailed data on container movements, gathered from two large international terminals, we simulate the impact of the two most important inspection policies that are being considered. We find that the current inspection regime being advanced by the U.S. Department of Homeland Security can only handle a small percentage of the total load. An alternate inspection protocol that emphasizes screening—a rapid primary scan of all containers, followed by a more careful secondary scan of only a few containers that fail the primary test—holds promise as a feasible solution for meeting the 100% scanning requirement

Non-covalent Functionalization of Graphene to Tune Its Band Gap and Stabilize Metal Nanoparticles on Its Surface

Support from the Spanish Government (project no. RTI2018101558-B-C21), Autonomous Regional Government (Junta de Andalucia ', group nos. PAIDI FQM273 and RMN342), and University of Jaen (no. EI_FQM6-2019) is gratefully acknowledged. Technical and human support provided by SCAI of the University of Jaen (UJA, MINECO, Junta de Andalucia ', and FEDER) is also acknowledged.Controlling graphene conductivity is crucial for its potential applications. With this focus, this paper shows the effect of the non-covalent bonding of a pyrimidine derivative (HIS) on the electronic properties of graphene (G). Several G-HIS hybrids are prepared through mild treatments keeping unaltered the structures of both G and HIS. The attachment of HIS to G occurs by π−π stacking of the HIS-aromatic residue with the G surface. This partially blocks the pz electrons of G, giving rise to the splitting of both the valence and conduction bands. Moreover, the width of the splitting is directly related to the HIS content. This fact allows the fine-tuning of the band gap of G-HIS hybrids. Furthermore, HIS keeps its metal-complexing ability in the G-HIS hybrids. Taking advantage of this, a G-HIS−Cu(0) composite was prepared by H2 plasma reduction of a precursor of the G-HIS−Cu(II) type. GHIS− Cu(0) contains Cu(0) clusters stabilized on the G surface due to interactions with the COO− functions of HIS. In an analogous hybrid, G-HIS−Au(0), the Au(0) NPs are also stabilized by COO− functions. This material, consisting of the coupling of Au(0) NPs and G-HIS, photocatalyzed water reduction under visible light radiation producing 12.5 μmol·g−1·h−1of hydrogen.Spanish Government RTI2018101558-B-C21Junta de Andalucia PAIDI FQM273 RMN342University of Jaen EI_FQM6-201

Prediction of the aero-elastic force in a labyrinth type seal and its impact on turbomachinery stability

Thesis (Mech.E)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 1983.MICROFICHE COPY AVAILABLE IN ARCHIVES AND ENGINEERINGIncludes bibliographical references.by Bruce E. Gans.Mech.