The Environment and Civil War: Exploring the Relationship Between the Environmental Performance Index and Incidence of Internal Armed Conflict

The state of the environment is receiving increasing attention. Environmental quality’s possible relationship to violent conflict attracts both popular and academic interest. Prior research has found support for the idea that environmental scarcity is related to higher occurrences of civil war. There have been few comprehensive quantitative studies regarding this relationship. This study tests a more general argument that higher environmental quality can lead to fewer occurrences of internal armed conflict. The study utilizes an environmental performance index found in the Quality of Government Standard Dataset to test its hypothesis. The study finds that the higher the environmental performance index of a state, the lower the annual incidence of internal armed conflict. The relationship found in this study should inspire further research on the relationship between environmental quality and civil war. Further attention to this subject may encourage increased priority toward environmental policy to prevent the incidence of civil war

High Temperature Fatigue Crack Growth Behavior of Ti-6Al-4V

Experimental evaluation of high temperature, Fatigue Crack Growth Rate (FCGR) data for Ti-6A1-4V, a titanium alloy, is presented. The FCGR data were measured at room temperature, 175, 230, 290 and 345°C using the Direct Current Potential Difference (DCPD) technique. Compact Tension (CT) specimens were used in the program and crack growth rates (da/dN) vs. Mode I stress intensity factor ranges (ΔΚ) were plotted as a function of temperature. A temperature rise from 175 to 345°C did not cause a substantial increase in crack growth rates within the Stage II region where a linear relationship describes the behavior. Fonnation of secondary cracks, observed at higher temperatures, may have slowed the crack propagation as observed in the fractography

The Catalysis of the Hydrogen-Oxygen Reaction by Aqueous Slurries of Thorium Oxide and Thorium-Uranium Oxide

Aqueous slurries of thorium oxide and thorium oxide containing urarium were investigated for their catalytic activity for the reaction of hydrogen and oxygen to form water. Pure thorium oxide. thorium-uranium oxide mixed crystals prepared by calcining coprecipitated oxalates, and thorium oxide with uranium oxide sorbed on the surface were used after calcining at 650, 800, and 1000 deg . The reaction rates were found to be first order with respect to hydrogen pressure and zero order with respect to oxygen pressure in all cases at temperatures from 230 to 300 deg - and total gas pressures from 100 to 2000 psi. For the pure thorium oxide an average activation energy of 41 kcal/mole and an average frequency factor of 4.6 x lO/sup 8/ moles/psi H/sub 2/hr-g of ThO/sub 2/ were found. Addition of uranium lowered both factors, the maximum effect giving a DELTA E/sub a/ of approximately 14 kcal with an A of approximately 10/sup -2/. Actual rates for all catalysts were within one order of magnitude when compared on a unit surface area basis. This compensation effect was explained on the basis of a two-site process, one site being related to the uranium concentration on the catalyst surface and the other characteristic of pure thorium oxide. A few tests on uranium trioxide slurries gave initial fast rates followed by slow ones, the change being accompanied by reduction of the surface uranium under the experimental conditions. The apparent activation energy for both surface conditions was 26 kcal/mole based on first order rate constants with frequency factors of 2.2 x 10/sup 4/ and 2.5 x 10/sup 3/ moles/psi H/sub 2/hr-g for the initial and final rates, respectively. (auth

Building fast and secure Web services with OKWS

Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2005.Includes bibliographical references (p. 69-74).OKWS is a Web server specialized for secure and fast delivery of dynamic content. It provides Web developers with a small set of tools powerful enough to build complex Web-based systems. Despite its emphasis on security, OKWS shows performance improvements compared to popular systems: when servicing fully dynamic, non-disk-bound database workloads, OKWS's throughput and responsiveness exceed that of Apache 2, Flash and Haboob. Experience with OKWS in a commercial deployment suggests it can reduce hardware and system management costs, while providing security guarantees absent in current systems. In the end, lessons gleaned from the OKWS project provide insight into how operating systems might better facilitate secure application design.by Maxwell Krohn.S.M

Information flow control for secure web sites

Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2008.Includes bibliographical references (leaves 117-125).Sometimes Web sites fail in the worst ways. They can reveal private data that can never be retracted [60, 72, 78, 79]. Or they can succumb to vandalism, and subsequently show corrupt data to users [27]. Blame can fall on the off-the-shelf software that runs the site (e.g., the operating system, the application libraries, the Web server, etc.), but more frequently (as in the above references), the custom application code is the guilty party. Unfortunately, the custom code behind many Web sites is difficult to secure and audit, due to large and rapidly-changing trusted computing bases (TCBs). A promising approach to reducing TCBs for Web sites is decentralized information flow control (DIFC) [21, 69, 113]. DIFC allows the split of a Web application into two types of components: those inside the TCB (trusted), and those without (untrusted). The untrusted components are large, change frequently, and do most of the computation. Even if buggy, they cannot move data contrary to security policy. Trusted components are much smaller, and configure the Web site's security policies. They need only change when the policy changes, and not when new features are introduced. Bugs in the trusted code can lead to compromise, but the trusted code is smaller and therefore easier to audit. The drawback of DIFC, up to now, is that the approach requires a major shift in how programmers develop applications and thus remains inaccessible to programmers using today's proven programming abstractions. This thesis proposes a new DIFC system, Flume, that brings DIFC controls to the operating systems and programming languages in wide use today. Its key contributions are: (1) a simplified DIFC model with provable security guarantees; (2) a new primitive called endpoints that bridges the gap between the Flume DIFC model and standard operating systems interfaces; (3) an implementation at user-level on Linux; and (4) success in securing a popular preexisting Web application (MoinMoin Wiki).by Maxwell Norman Krohn.Ph.D

Making information flow explicit in HiStar

HiStar is a new operating system designed to minimize the amount of code that must be trusted. HiStar provides strict information flow control, which allows users to specify precise data security policies without unduly limiting the structure of applications. HiStar's security features make it possible to implement a Unix-like environment with acceptable performance almost entirely in an untrusted user-level library. The system has no notion of superuser and no fully trusted code other than the kernel. HiStar's features permit several novel applications, including privacy-preserving, untrusted virus scanners and a dynamic Web server with only a few thousand lines of trusted code.National Science Foundation (U.S.) (Cybertrust Award CNS-0716806)National Science Foundation (U.S.) (Cybertrust/DARPA Grant CNS-0430425

Feasibility study for a numerical aerodynamic simulation facility. Volume 1

A Numerical Aerodynamic Simulation Facility (NASF) was designed for the simulation of fluid flow around three-dimensional bodies, both in wind tunnel environments and in free space. The application of numerical simulation to this field of endeavor promised to yield economies in aerodynamic and aircraft body designs. A model for a NASF/FMP (Flow Model Processor) ensemble using a possible approach to meeting NASF goals is presented. The computer hardware and software are presented, along with the entire design and performance analysis and evaluation

Non-relativistic effective theory of dark matter direct detection

Dark matter direct detection searches for signals coming from dark matter scattering against nuclei at a very low recoil energy scale ~ 10 keV. In this paper, a simple non-relativistic effective theory is constructed to describe interactions between dark matter and nuclei without referring to any underlying high energy models. It contains the minimal set of operators that will be tested by direct detection. The effective theory approach highlights the set of distinguishable recoil spectra that could arise from different theoretical models. If dark matter is discovered in the near future in direct detection experiments, a measurement of the shape of the recoil spectrum will provide valuable information on the underlying dynamics. We bound the coefficients of the operators in our non-relativistic effective theory by the null results of current dark matter direct detection experiments. We also discuss the mapping between the non-relativistic effective theory and field theory models or operators, including aspects of the matching of quark and gluon operators to nuclear form factors.Comment: 35 pages, 3 figures, Appendix C.3 revised, acknowledgments and references adde