A numerical study of ENO and TVD schemes for shock capturing

The numerical performance of a second-order upwind-based total variation diminishing (TVD) scheme and that of a uniform second-order essentially non-oscillatory (ENO) scheme for shock capturing are compared. The TVD scheme used is a modified version of Liou, using the flux-difference splitting (FDS) of Roe and his superbee function as the limiter. The construction of the basic ENO scheme is based on Harten, Engquist, Osher, and Chakravarthy, and the 2-D extensions are obtained by using a Strang-type of fractional-step time-splitting method. Numerical results presented include both steady and unsteady, 1-D and 2-D calculations. All the chosen test problems have exact solutions so that numerical performance can be measured by comparing the computer results to them. For 1-D calculations, the standard shock-tube problems of Sod and Lax are chosen. A very strong shock-tube problem, with the initial density ratio of 400 to 1 and pressure ratio of 500 to 1, is also used to study the behavior of the two schemes. For 2-D calculations, the shock wave reflection problems are adopted for testing. The cases presented in this report include flows with Mach numbers of 2.9, 5.0, and 10.0

Heat Capacities and Thermodynamic Properties of Two Tetramethylammonium Halides

Heat capacities of tetramethylammonium chloride and bromide were determined by low‐temperature adiabatic calorimetry from 5° to 350°K. Derived thermodynamic properties were then calculated. Two transitions were found in the chloride: a sharp, apparently first‐order transition occurs at 75.76°K with an entropy of transition of 0.37 cal mole—1 °K—1 and a lambda‐shaped transition at 184.85°K with an entropy increment of 0.14 cal mole—1 °K—1. No anomaly has been observed in the bromide. Molal values of heat capacity, entropy, and free energy function at 298.15°K for the chloride and the bromide are: 37.51, 38.64, 45.58, 47.99, and —23.36, —25.36 cal mole—1 °K—1, respectively.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/69935/2/JCPSA6-36-9-2420-1.pd

Roles of Adipokines in Digestive Diseases: Markers of Inflammation, Metabolic Alteration and Disease Progression

Adipose tissue is a highly dynamic endocrine tissue and constitutes a central node in the interorgan crosstalk network through adipokines, which cause pleiotropic effects, including the modulation of angiogenesis, metabolism, and inflammation. Specifically, digestive cancers grow anatomically near adipose tissue. During their interaction with cancer cells, adipocytes are reprogrammed into cancer-associated adipocytes and secrete adipokines to affect tumor cells. Moreover, the liver is the central metabolic hub. Adipose tissue and the liver cooperatively regulate whole-body energy homeostasis via adipokines. Obesity, the excessive accumulation of adipose tissue due to hyperplasia and hypertrophy, is currently considered a global epidemic and is related to low-grade systemic inflammation characterized by altered adipokine regulation. Obesity-related digestive diseases, including gastroesophageal reflux disease, Barrett\u27s esophagus, esophageal cancer, colon polyps and cancer, non-alcoholic fatty liver disease, viral hepatitis-related diseases, cholelithiasis, gallbladder cancer, cholangiocarcinoma, pancreatic cancer, and diabetes, might cause specific alterations in adipokine profiles. These patterns and associated bases potentially contribute to the identification of prognostic biomarkers and therapeutic approaches for the associated digestive diseases. This review highlights important findings about altered adipokine profiles relevant to digestive diseases, including hepatic, pancreatic, gastrointestinal, and biliary tract diseases, with a perspective on clinical implications and mechanistic explorations

Analysis of traditional Chinese architecture

Thesis (M. Arch.)--Massachusetts Institute of Technology, Dept. of Architecture, 1983.MICROFICHE COPY AVAILABLE IN ARCHIVES AND ROTCHIncludes bibliographical references (p. 152-155).This thesis deals with a process of analyzing specific examples in traditional Chinese architecture in an attempt to understand and identify the underlying principles that make it essentially Chinese. The basic intent is that the development of this process of observation would later inform a process of design that would generate a 'new' architecture which could be worthily referred to as a continuum of the traditional architecture. The examples studied range from Palace and Temple architecture to Chinese gardens. To varying degrees, these places have been analyzed in terms of their spatial organization, degrees of public and private, structural systems, use of light, method of composition, system of proportions and system of circulation.by Pamela Grace Chang Sing.M.Arch

Design and Development of the Reactive BGP peering in Software-Defined Routing Exchanges

The Software-Defined Networking (SDN) is considered to be an improved solution for applying flexible control and operation recently in the network. Its characteristics include centralized management, global view, as well as fast adjustment and adaptation. Many experimental and research networks have already migrated to the SDN-enabled architecture. As the global network continues to grow in a fast pace, how to use SDN to improve the networking fields becomes a popular topic in research. One of the interesting topics is to enable routing exchanges among the SDN-enabled network and production networks. However, considering that many production networks are still operated on legacy architecture, the enabled SDN routing functionalities have to support hybrid mode in operation. In this paper, we propose a routing exchange mechanism by enabling reactive BGP peering actions among the SDN and legacy network components. The results of experiments show that our SDN controller is able to mask as an Autonomous System (AS) to exchange routing information with other BGP routers

Controlling electric double-layer capacitance and pseudocapacitance in heteroatom-doped carbons derived from hypercrosslinked microporous polymers

© 2018 Hypercrosslinked polymers (HCPs) are an important class of porous materials that can be synthesized from aromatic precursors using a one-step “knitting” procedure. This scalable process allows wide synthetic diversity and ease of functionalization. However, pristine HCPs lack electrical conductivity, which limits their potential for electrochemical applications. Supercapacitors are energy storage devices with advantages over conventional batteries such as high power densities, rapid charge speeds, and superior cyclability. In this work, carbonization of functionalized HCPs yields highly conductive and porous materials that can be used as supercapacitor electrodes. Both electric double-layer capacitance (EDLC) and pseudocapacitance (PC) mechanisms are observed. The relative EDLC and PC contributions were quantified for a range of 20 HCP-derived materials, thus allowing a controlled approach to tuning the energy storage properties. The HCP-based carbons show ideal supercapacitor behavior and the best performing material, which shows 63% PC, displays exceptionally high capacitances of up to 374 F g −1 , excellent capacitance retention at fast charging speeds, and stability for up to 15,000 charge/discharge cycles

Sequence-Dependent Self-Coacervation in High Charge-Density Polyampholytes

Polyampholytes, which contain both positive and negative charges along the backbone, represent a classical model system for certain types of `intrinsically-disordered proteins\u27 (IDPs). IDPs can possess biological functionality, even in an unfolded state, including the formation of phase-separated regions within a cell; while driven by a number of interactions, electrostatic attractions are thought to be key to forming these structures. This process of electrostatically-driven liquid-liquid phase separation, known as `complex coacervation\u27, can also be observed in simpler polymer or biopolymer systems. In this paper, we use a series of model polyampholytic polypeptides of increasing blockiness, that undergo `self-coacervation\u27 due to charge attraction between polycation and polyanion blocks along the same polymer chain. We show that these polypeptides undergo complex coacervation when sequences have at least 8-12 adjacent like-charges, with increasing blockiness leading to a larger two-phase region. We simultaneously develop a theory built on the transfer-matrix formalism developed by the authors, to show how blockiness increases the strength of electrostatic interactions and subsequently promote phase separation. We explore a tradeoff that emerges due to the presence of `charge-pattern interfaces\u27 where the sequence of polyampholyte charges switches sign, and how these contrast with chain-ends in equivalent homopolyelectrolyte coacervates

Designing Electrostatic Interactions via Polyelectrolyte Monomer Sequence

Charged polymers are ubiquitous in biological systems because electrostatic interactions can drive complicated structure formation and respond to environmental parameters such as ionic strength and pH. In these systems, function emerges from sophisticated molecular design; for example, intrinsically disordered proteins leverage specific sequences of monomeric charges to control the formation and function of intracellular compartments known as membraneless organelles. The role of a charged monomer sequence in dictating the strength of electrostatic interactions remains poorly understood despite extensive evidence that sequence is a powerful tool biology uses to tune soft materials. In this article, we use a combination of theory, experiment, and simulation to establish the physical principles governing sequence-driven control of electrostatic interactions. We predict how arbitrary sequences of charge give rise to drastic changes in electrostatic interactions and correspondingly phase behavior. We generalize a transfer matrix formalism that describes a phase separation phenomenon known as “complex coacervation” and provide a theoretical framework to predict the phase behavior of charge sequences. This work thus provides insights into both how charge sequence is used in biology and how it could be used to engineer properties of synthetic polymer systems