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ASSESMENT OF PARTICLE CANDIDATES FOR FALLING PARTICLE RECEIVER APPLICATIONS THROUGH IRRADIANCE AND THERMAL CYCLING.
Abstract not provided.
ASSESMENT OF PARTICLE CANDIDATES FOR FALLING PARTICLE RECEIVER APPLICATIONS THROUGH IRRADIANCE AND THERMAL CYCLING.
Abstract not provided.
The changing character of household waste in the Czech Republic between 1999 and 2009 as a function of home heating methods
Highlights: • The character of household waste in the three different types of households were assesed. • The quantity, density and composition of household waste were determined. • The physicochemical characteristics were determined. • The changing character of household waste during past 10 years was described. • The potential of energy recovery of household waste in Czech republic was assesed. - Abstract: The authors of this paper report on the changing character of household waste, in the Czech Republic between 1999 and 2009 in households differentiated by their heating methods. The data presented are the result of two projects, financed by the Czech Ministry of Environment, which were undertaken during this time period with the aim of focusing on the waste characterisation and complete analysis of the physicochemical properties of the household waste. In the Czech Republic, the composition of household waste varies significantly between different types of households based on the methods of home heating employed. For the purposes of these studies, the types of homes were divided into three categories – urban, mixed and rural. Some of the biggest differences were found in the quantities of certain subsample categories, especially fine residue (matter smaller than 20 mm), between urban households with central heating and rural households that primarily employ solid fuel such coal or wood. The use of these solid fuels increases the fraction of the finer categories because of the higher presence of ash. Heating values of the residual household waste from the three categories varied very significantly, ranging from 6.8 MJ/kg to 14.2 MJ/kg in 1999 and from 6.8 MJ/kg to 10.5 MJ/kg in 2009 depending on the type of household and season. The same factors affect moisture of residual household waste which varied from 23.2% to 33.3%. The chemical parameters also varied significantly, especially in the quantities of Tl, As, Cr, Zn, Fe and Mn, which were higher in rural households. Because knowledge about the properties of household waste, as well as its physicochemical characteristics, is very important not only for future waste management, but also for the prediction of the behaviour and influence of the waste on the environment as the country continues to streamline its legislation to the European Union’s solid waste mandates, the results of these studies were employed by the Czech Ministry of Environment to optimise the national waste management strategy.
Innovative urban forestry governance in Melbourne?: Investigating “green placemaking” as a nature-based solution
Highlights: • Scholars have called for a re-assessment of urban environmental governance. • We examine the City of Melbourne's Urban Forest Strategy (UFS). • Co-governance arrangements in the UFS foster situated decision making pluralism. • Melbourne’s UFS links aims of biodiversity to those of socio-ecological resilience. A nature-based approach to climate resilience aims to challenge and re-frame conventional environmental management methods by refocusing solutions from technological strategies to socio-ecological principles such as human well-being and community-based governance models, thereby improving and legitimizing the delivery of ecosystem services (ES). There are, however, many challenges to applying a socio-ecological agenda to urban climate resilience and thereby re-framing ES delivery as community and people focused, a knowledge gap extensively outlined in the environmental governance literature. In this paper, we aim to contribute to this re-assesment of urban environmental governance by examining the City of Melbourne's approach to urban re-naturing governance from a place-based perspective. Here we focus on the city's internationally-acclaimed urban forest strategy (UFS), investigating how and to which extent the governance arrangements embedded within the UFS draw strength from diverse perspectives and allow for institutional arrangements that support “situated” reflexive decision making and co-creation. We find that Melbourne's UFS governance process fosters green placemaking by re-focusing climate adaptation solutions from technological strategies to situated socio-ecological principles such as human well-being and community-based decision making. In this sense, this case provides valuable insight for the broader UGI governance field regarding the opportunities and challenges associated with a socio-cultural approach to urban re-naturing and ES delivery.
Patterns of Response After Preoperative Intensity-Modulated Radiation Therapy and Capecitabine/Oxaliplatin in Rectal Cancer: Is There Still a Place for Ecoendoscopic Ultrasound?
Purpose: The main goals of preoperative chemoradiotherapy (CHRT) in rectal cancer are to achieve pathological response and to ensure tumor control with functional surgery when possible. Assessment of the concordance between clinical and pathological responses is necessary to make decisions regarding alternative conservative procedures. The present study evaluates the patterns of response after a preoperative CHRT regimen, and the value of endoscopic ultrasound (EUS) in assessing response. Methods and Materials: A total of 51 EUS-staged T3 to T4 and/or N0 to N+ rectal cancer patients received preoperative CHRT (intensity-modulated radiation therapy and capecitabine/oxaliplatin (XELOX) followed by radical resection. Clinical response was assesed by EUS. Rates of pathological tumor regression grade (TRG) and lymph node (LN) involvement were determined in the surgical specimen. Clinical and pathological responses were compared, and the accuracy of EUS in assessing response was calculated. Results: Twenty-four patients (45%) achieved a major pathological response (complete or >95% pathological response (TRG 3+/4)). Sensitivity, specificity, negative predictive value, and positive predictive value of EUS in predicting pathological T response after preoperative CHRT were 77.8%, 37.5%, 60%, and 58%, respectively. The EUS sensitivity, specificity, negative predictive value, and positive predictive value for nodal staging were 44%, 88%, 88%, and 44%, respectively. Furthermore, EUS after CHRT accurately predicted the absence of LN involvement in 7 of 7 patients (100%) with major pathological response of the primary tumor. Conclusion: Preoperative IMRT with concomitant XELOX induces favorable rates of major pathological response. EUS has a limited ability to predict primary tumor response after preoperative CHRT, but it is useful for accurately determining LN status. EUS may have a potential value in identifying patients with a very low risk of LN involvement in association with a good pathological response as potential candidates for conservative local surgical protocols.
Scalar excursions in large-eddy simulations
Here, the range of values of scalar fields in turbulent flows is bounded by their boundary values, for passive scalars, and by a combination of boundary values, reaction rates, phase changes, etc., for active scalars. The current investigation focuses on the local conservation of passive scalar concentration fields and the ability of the large-eddy simulation (LES) method to observe the boundedness of passive scalar concentrations. In practice, as a result of numerical artifacts, this fundamental constraint is often violated with scalars exhibiting unphysical excursions. The present study characterizes passive-scalar excursions in LES of a shear flow and examines methods for diagnosis and assesment of the problem. The analysis of scalar-excursion statistics provides support of the main hypothesis of the current study that unphysical scalar excursions in LES result from dispersive errors of the convection-term discretization where the subgrid-scale model (SGS) provides insufficient dissipation to produce a sufficiently smooth scalar field. In the LES runs three parameters are varied: the discretization of the convection terms, the SGS model, and grid resolution. Unphysical scalar excursions decrease as the order of accuracy of non-dissipative schemes is increased, but the improvement rate decreases with increasing order of accuracy. Two SGS models are examined, the stretched-vortex and a constant-coefficient Smagorinsky. Scalar excursions strongly depend on the SGS model. The excursions are significantly reduced when the characteristic SGS scale is set to double the grid spacing in runs with the stretched-vortex model. The maximum excursion and volume fraction of excursions outside boundary values show opposite trends with respect to resolution. The maximum unphysical excursions increase as resolution increases, whereas the volume fraction decreases. The reason for the increase in the maximum excursion is statistical and traceable to the number of grid points (sample size) which increases with resolution. In contrast, the volume fraction of unphysical excursions decreases with resolution because the SGS models explored perform better at higher grid resolution.
Performance Analysis of Large Scale HPC Workflows for Earth System Models
Climate assessment reports, such as the Intergovernmental Panel on Climate Change’s 5th assesment report [IPCC AR5; IPCC et al., 2014] or the United States National Climate Assessment [U.S. Global Change Research Program, 2014], increasingly rely on many-ensemble climate projections from fully-coupled Earth system models (ESM) to asses possible future climate states. ESM participate in a large set of Coupled Model Intercomparson Projects (CMIP) to better understand their models and the climate system, so that they may provide credible climate projections. However, fully participating in these intercomparison exercises represents an extremely large computational personnel burden for modeling centers [Eyring et al., 2016, Williams et al., 2016a]. However, there has been little attention within the climate modeling community paid to the in situ performance of ESMs up until now. Recently a computational performance model intercomparison project (CPMIP) for CMIP6 has begun [Balaji et al., 2017], but there has not yet been an effort to gather, process, and analyze the historical performance data that has been saved within archived log files from previous modeling efforts, nor the development of performance analysis system capable of providing detailed statistical analyses or visualizations of this performance data. Therefore, we’ve begun a joint effort to analyze the historical and current performance data on both GFDL and OLCF modeling systems. Here, we have developed a preliminary performance analysis system to captue, analyize, and visualize end-to-end in situ performance data and applied it to NOAA/GFDL’s post-processing system. Through the course of the project a number of performance improvements have been made, with the steps necessary to handle the expected volume of data (Big Data) likely to come out of the CMIP6 exercises (TB to PB) provided. We have also begun developing a statistical workload model that will allow modeling centers to determined their expected scientific throughput in the context of expected resource (computational and personnel) availability and accounting for typical workflow disruptions. This will allow them to develop a CMIP participation strategy and maximize their level of participation in the exercises. We expect this infrastructure, and the data it produces, to ultimately allow us to identify performance issues and workflow errors that exist across Earth system modeling centers, and possibly HPC modeling centers in general. Center-independent solutions to workflow or performance issues would help alleviate the computational burden for CMIP6+ modeling projects and should realize both labor and cost savings benefits throughout the CMIP community.
Correlations Between Metallurgical Characterization Studies, Exploratory Mechanical Tests, and Continuum Mechanics Approaches to Constitutive Equations
Austenitic stainless steels, such as types 316 and 304, are widely used as pressure vessel materials in the temperature range of 425 to 650 C. Stainless steel specimens were tested to rupture at two different stress levels sigma and sigma 2 sigma 1 sigma 2) to establish the normal stain-time behavior. A subsequent test was performed in which the specimen was crept at the higher stress (sigma 1) to the beginning of the secondary stage of creep, presumed to be the strain/time conditions at which a steady state microstructure is developed, and then the stress was reduced to the lower level (sigma 2). The associated microstructure, and significance of this microstructure on the creep strain-hardening model for variable uniaxial loads were assesed and found to be consistent with the use of creep-recovery models at high stresses and temperatures and strain-hardening models at low stresses and tempertures.
Develop and test fuel cell powered on-site integrated total energy systems. Phase 3: Full-scale power plant development
The testing of two 25-cell stacks of the 13 inch x 23 inch cell size (about 4kW) was carried out for 7000 and 8400 hours, respectively. A 25kW stack containing 175 cells of the same size and based on the same technology was constructed and is on test. A third 4kW stack, which will contain 24 cells, will comprise several new technology features; these will be assesed for performance and durability in long-term testing.
Combustion research in the Internal Fluid Mechanics Division
The goal of this research is to bring computational fluid dynamics to a state of practical application for the aircraft engine industry. The approach is to have a strongly integrated computational and experimental program for all the disciplines associated with the gas turbine and other aeropropulsion systems by advancing the understanding of flow physics, heat transfer, and combustion processes. The computational and experimental research is integrated in the following way: the experiments that are performed provide an empirical data set so that physical models can be formulated to describe the processes that are occurring - for example, turbulence or chemical reaction. These experiments also form a data base for those who are doing code development by providing experimental data against which the codes can be verified and assesed. Models are generated as closure to some of the numerical codes, and they also provide physical insight for experiments. At the same time, codes which solve the complete Navier-Stokes equations can be used as a kind of numerical experiment from which far more extensive data can be obtained than ever could be obtained experimentally. This could provide physical insight into the complex processes that are taking place. These codes are also exercised against experimental data to assess the accuracy and applicability of models.
Structure property behavior of polyimide siloxane segmented copolymers
Procedures were developed for preparing soluble fully imidized polyimide-polydimethyl siloxane segmented copolymers of wide ranging compositions. At low siloxane levels, the materails behave as modified polyimides. At higher concentrations, the materials are analogous to thermoplastic elastomers. Characterization by dynamic mechanical and thermal analysis methods will be reported along with an assesment of the bulk mechanical properties and the surface behavior. The surface behavior is particularly interesting since the materials can be tailored to have siloxane surfaces even at rather low siloxane contents. This influences a number of properties such as the coefficient of friction and, importanly, the degradation of these materials under aggressive oxygen environments (e.g., atomic oxygen, oxygen plasma).
International cooperation in the Space Station programme - Assessing the experience to date
The origins and framework for cooperation in the Space Station program are outlined. Particular attention is paid to issues and commitments between the countries and to the political context of the Station partnership. A number of conclusions concerning international cooperation in space are drawn based on the Space Station experience. Among these conclusions is the assertion that an international partnership requires realistic assesments, mutual trust, and strong commitments in order to work.
Computer Simulation Performed for Columbia Project Cooling System
This demo shows a high-fidelity simulation of the air flow in the main computer room housing the Columbia (10,024 intel titanium processors) system. The simulation asseses the performance of the cooling system and identified deficiencies, and recommended modifications to eliminate them. It used two in house software packages on NAS supercomputers: Chimera Grid tools to generate a geometric model of the computer room, OVERFLOW-2 code for fluid and thermal simulation. This state-of-the-art technology can be easily extended to provide a general capability for air flow analyses on any modern computer room. Columbia_CFD_black.tiff
Micro Explorers
Inspired by the world of insects and animals, the well-proven natural 'explorers' on this planet, this study is a fesibility assesment of building efficient and cost-effective 'microexplorers' for future NASA missions.
Hydrogen Hazards Assessment Protocol (HHAP): Approach and Methodology
This viewgraph presentation reviews the approach and methodology to develop a assessment protocol for hydrogen hazards. Included in the presentation are the reasons to perform hazards assessment, the types of hazard assessments that exist, an analysis of hydrogen hazards, specific information about the Hydrogen Hazards Assessment Protocol (HHAP). The assessment is specifically tailored for hydrogen behavior. The end product of the assesment is a compilation of hazard, mitigations and associated factors to facilitate decision making and achieve the best practice.
Implementation on Landsat Data of a Simple Cloud Mask Algorithm Developed for MODIS Land Bands
This letter assesses the performance on Landsat-7 images of a modified version of a cloud masking algorithm originally developed for clear-sky compositing of Moderate Resolution Imaging Spectroradiometer (MODIS) images at northern mid-latitudes. While data from recent Landsat missions include measurements at thermal wavelengths, and such measurements are also planned for the next mission, thermal tests are not included in the suggested algorithm in its present form to maintain greater versatility and ease of use. To evaluate the masking algorithm we take advantage of the availability of manual (visual) cloud masks developed at USGS for the collection of Landsat scenes used here. As part of our evaluation we also include the Automated Cloud Cover Assesment (ACCA) algorithm that includes thermal tests and is used operationally by the Landsat-7 mission to provide scene cloud fractions, but no cloud masks. We show that the suggested algorithm can perform about as well as ACCA both in terms of scene cloud fraction and pixel-level cloud identification. Specifically, we find that the algorithm gives an error of 1.3% for the scene cloud fraction of 156 scenes, and a root mean square error of 7.2%, while it agrees with the manual mask for 93% of the pixels, figures very similar to those from ACCA (1.2%, 7.1%, 93.7%).
ILRS Website Update
The ILRS website, http://ilrs.gsfc.nasa.gov, is the central source of information for all aspects of the service. The website provides information on the organization and operation of the ILRS and descriptions of ILRS components data, and products. Furthermore, the website provides an entry point to the archive of these data products available through the data centers. Links are provided to extensive information on the ILRS network stations including performance assesments and data quality evaluations. Descriptions of suported satellite missions (current, future, and past) are provided to aid in station acquisition and data analysis. The website was reently redesigned. Content was reviewed during the update process, ensuring information is current and useful. This poster will provide specific examples of key sections, applicaitons, and webpages.