Stirling material technology

The Stirling engine is an external combustion engine that offers the advantage of high fuel economy, low emissions, low noise, and low vibrations compared to current internal combustion automotive engines. The most critical component from a materials viewpoint is the heater head consisting of the cylinders, heating tubes, and regenerator housing. Materials requirements for the heater head include compatibility with hydrogen, resistance to hydrogen permeation, high temperature oxidation/corrosion resistance, and high temperature creep-rupture and fatigue properties. A materials research and technology program identified the wrought alloys CG-27 and 12RN72 and the cast alloys XF-818, NASAUT 4G-A1, and NASACC-1 as candidate replacements for the cobalt containing alloys used in current prototype engines. It is concluded that manufacture of the engine is feasible from low cost iron-base alloys rather than the cobalt alloys used in prototype engines. Results of research that lead to this conclusion are presented

Internal erosion of granular materials – Identification of erodible fine particles as a basis for numerical calculations

In geohydromechanics internal erosion is a process which is still hardly to be quantified both spatially as well as temporally. The transport of fine particles, which is caused by increased hydraulic gradients, is influenced by the pore structure of the coarse grained fabric. The microstructural information of the pore constriction size distribution (CSD) of the solid skeleton has therefore to be taken into account when internal erosion is analyzed either analytically or numerically. The CSD geometrically defines the amount of fine particles, which potentially can be eroded away for a given hydraulic force. The contribution introduces experimental and numerical calculations which aim at the quantification of the amount of erodible fines. Based on this approach a multiphase continuum-based numerical model is used to back calculate the process of internal erosion for one material of the well-known experimental investigation of Skempton & Brogan (1994)[1]

Toward an Ontological Treatment of Disease and Diagnosis

Many existing biomedical vocabulary standards rest on incomplete, inconsistent or confused accounts of basic terms pertaining to diseases, diagnoses, and clinical phenotypes. Here we outline what we believe to be a logically and biologically coherent framework for the representation of such entities and of the relations between them. We defend a view of disease as involving in every case some physical basis within the organism that bears a disposition toward the execution of pathological processes. We present our view in the form of a list of terms and definitions designed to provide a consistent starting point for the representation of both disease and diagnosis in information systems in the future

Visual exploration of climate variability changes using wavelet analysis

Due to its nonlinear nature, the climate system shows quite high natural variability on different time scales, including multiyear oscillations such as the El Ni˜no Southern Oscillation phenomenon. Beside a shift of the mean states and of extreme values of climate variables, climate change may also change the frequency or the spatial patterns of these natural climate variations. Wavelet analysis is a well established tool to investigate variability in the frequency domain. However, due to the size and complexity of the analysis results, only few time series are commonly analyzed concurrently. In this paper we will explore different techniques to visually assist the user in the analysis of variability and variability changes to allow for a holistic analysis of a global climate model data set consisting of several variables and extending over 250 years. Our new framework and data from the IPCC AR4 simulations with the coupled climate model ECHAM5/MPI-OM are used to explore the temporal evolution of El Ni˜no due to climate change

Energy Efficient and Reliable ARQ Scheme (ER-ACK) for Mission Critical M2M/IoT Services

Wireless sensor networks (WSNs) are the main infrastructure for machine to machine (M2M) and Internet of thing (IoT). Since various sophisticated M2M/IoT services have their own quality-of-service (QoS) requirements, reliable data transmission in WSNs is becoming more important. However, WSNs have strict constraints on resources due to the crowded wireless frequency, which results in high collision probability. Therefore a more efficient data delivering scheme that minimizes both the transmission delay and energy consumption is required. This paper proposes energy efficient and reliable data transmission ARQ scheme, called energy efficient and reliable ACK (ER-ACK), to minimize transmission delay and energy consumption at the same time. The proposed scheme has three aspects of advantages compared to the legacy ARQ schemes such as ACK, NACK and implicit-ACK (I-ACK). It consumes smaller energy than ACK, has smaller transmission delay than NACK, and prevents the duplicated retransmission problem of I-ACK. In addition, resource considered reliability (RCR) is suggested to quantify the improvement of the proposed scheme, and mathematical analysis of the transmission delay and energy consumption are also presented. The simulation results show that the ER-ACK scheme achieves high RCR by significantly reducing transmission delay and energy consumption

An Ontology-Based Framework for Clinical Research Databases

The Ontology-Based eXtensible data model (OBX) was developed to serve as a framework for the development of a clinical research database in the Immunology Database and Analysis Portal (ImmPort) system. OBX was designed around the logical structure provided by the Basic Formal Ontology (BFO) and the Ontology for Biomedical Investigations (OBI). By using the logical structure provided by these two well-formulated ontologies, we have found that a relatively simple, extensible data model could be developed to represent the relatively complex domain of clinical research. In addition, the common framework provided by the BFO should make it straightforward to utilize OBX database data dictionaries based on reference and application ontologies from the OBO Foundry

An improved ontological representation of dendritic cells as a paradigm for all cell types

The Cell Ontology (CL) is designed to provide a standardized representation of cell types for data annotation. Currently, the CL employs multiple is_a relations, defining cell types in terms of histological, functional, and lineage properties, and the majority of definitions are written with sufficient generality to hold across multiple species. This approach limits the CL’s utility for cross-species data integration. To address this problem, we developed a method for the ontological representation of cells and applied this method to develop a dendritic cell ontology (DC-CL). DC-CL subtypes are delineated on the basis of surface protein expression, systematically including both species-general and species-specific types and optimizing DC-CL for the analysis of flow cytometry data. This approach brings benefits in the form of increased accuracy, support for reasoning, and interoperability with other ontology resources. 104. Barry Smith, “Toward a Realistic Science of Environments”, Ecological Psychology, 2009, 21 (2), April-June, 121-130. Abstract: The perceptual psychologist J. J. Gibson embraces a radically externalistic view of mind and action. We have, for Gibson, not a Cartesian mind or soul, with its interior theater of contents and the consequent problem of explaining how this mind or soul and its psychological environment can succeed in grasping physical objects external to itself. Rather, we have a perceiving, acting organism, whose perceptions and actions are always already tuned to the parts and moments, the things and surfaces, of its external environment. We describe how on this basis Gibson sought to develop a realist science of environments which will be ‘consistent with physics, mechanics, optics, acoustics, and chemistry’