24,372 research outputs found
A cost-benefit analysis of a pellet boiler with electrostatic precipitator versus conventional biomass technology: A case study of an institutional boiler in Syracuse, New York
BACKGROUND: Biomass facilities have received increasing attention as a strategy to increase the use of renewable fuels and decrease greenhouse gas emissions from the electric generation and heating sectors, but these facilities can potentially increase local air pollution and associated health effects. Comparing the economic costs and public health benefits of alternative biomass fuel, heating technology, and pollution control technology options provides decision-makers with the necessary information to make optimal choices in a given location.
METHODS: For a case study of a combined heat and power biomass facility in Syracuse, New York, we used stack testing to estimate emissions of fine particulate matter (PM2.5) for both the deployed technology (staged combustion pellet boiler with an electrostatic precipitator) and a conventional alternative (wood chip stoker boiler with a multicyclone). We used the atmospheric dispersion model AERMOD to calculate the contribution of either fuel-technology configuration to ambient primary PM2.5 in a 10 km x 10 km region surrounding the facility, and we quantified the incremental contribution to population mortality and morbidity. We assigned economic values to health outcomes and compared the health benefits of the lower-emitting technology with the incremental costs.
RESULTS: In total, the incremental annualized cost of the lower-emitting pellet boiler was 1.7 million annually, greatly exceeding the differential costs even when accounting for uncertainties. Our analyses also showed complex spatial patterns of health benefits given non-uniform age distributions and air pollution levels.
CONCLUSIONS: The incremental investment in a lower-emitting staged combustion pellet boiler with an electrostatic precipitator was well justified by the population health improvements over the conventional wood chip technology with a multicyclone, even given the focus on only primary PM2.5 within a small spatial domain. Our analytical framework could be generalized to other settings to inform optimal strategies for proposed new facilities or populations.This research was supported by the New York State Energy Research and Development Authority (NYSERDA), via an award to the Northeast States for Coordinated Air Use Management (Agreement #92229). The SCICHEM work of KMZ was supported by the Electric Power Research Institute (EPRI)
ERIGrid Holistic Test Description for Validating Cyber-Physical Energy Systems
Smart energy solutions aim to modify and optimise the operation of existing energy infrastructure. Such cyber-physical technology must be mature before deployment to the actual infrastructure, and competitive solutions will have to be compliant to standards still under development. Achieving this technology readiness and harmonisation requires reproducible experiments and appropriately realistic testing environments. Such testbeds for multi-domain cyber-physical experiments are complex in and of themselves. This work addresses a method for the scoping and design of experiments where both testbed and solution each require detailed expertise. This empirical work first revisited present test description approaches, developed a newdescription method for cyber-physical energy systems testing, and matured it by means of user involvement. The new Holistic Test Description (HTD) method facilitates the conception, deconstruction and reproduction of complex experimental designs in the domains of cyber-physical energy systems. This work develops the background and motivation, offers a guideline and examples to the proposed approach, and summarises experience from three years of its application.This work received funding in the European Community’s Horizon 2020 Program (H2020/2014–2020)
under project “ERIGrid” (Grant Agreement No. 654113)
An Assessment to Benchmark the Seismic Performance of a Code-Conforming Reinforced-Concrete Moment-Frame Building
This report describes a state-of-the-art performance-based earthquake engineering methodology
that is used to assess the seismic performance of a four-story reinforced concrete (RC) office
building that is generally representative of low-rise office buildings constructed in highly seismic
regions of California. This “benchmark” building is considered to be located at a site in the Los
Angeles basin, and it was designed with a ductile RC special moment-resisting frame as its
seismic lateral system that was designed according to modern building codes and standards. The
building’s performance is quantified in terms of structural behavior up to collapse, structural and
nonstructural damage and associated repair costs, and the risk of fatalities and their associated
economic costs. To account for different building configurations that may be designed in
practice to meet requirements of building size and use, eight structural design alternatives are
used in the performance assessments.
Our performance assessments account for important sources of uncertainty in the ground
motion hazard, the structural response, structural and nonstructural damage, repair costs, and
life-safety risk. The ground motion hazard characterization employs a site-specific probabilistic
seismic hazard analysis and the evaluation of controlling seismic sources (through
disaggregation) at seven ground motion levels (encompassing return periods ranging from 7 to
2475 years). Innovative procedures for ground motion selection and scaling are used to develop
acceleration time history suites corresponding to each of the seven ground motion levels.
Structural modeling utilizes both “fiber” models and “plastic hinge” models. Structural
modeling uncertainties are investigated through comparison of these two modeling approaches,
and through variations in structural component modeling parameters (stiffness, deformation
capacity, degradation, etc.). Structural and nonstructural damage (fragility) models are based on
a combination of test data, observations from post-earthquake reconnaissance, and expert
opinion. Structural damage and repair costs are modeled for the RC beams, columns, and slabcolumn connections. Damage and associated repair costs are considered for some nonstructural
building components, including wallboard partitions, interior paint, exterior glazing, ceilings,
sprinkler systems, and elevators. The risk of casualties and the associated economic costs are
evaluated based on the risk of structural collapse, combined with recent models on earthquake
fatalities in collapsed buildings and accepted economic modeling guidelines for the value of
human life in loss and cost-benefit studies.
The principal results of this work pertain to the building collapse risk, damage and repair
cost, and life-safety risk. These are discussed successively as follows.
When accounting for uncertainties in structural modeling and record-to-record variability
(i.e., conditional on a specified ground shaking intensity), the structural collapse probabilities of
the various designs range from 2% to 7% for earthquake ground motions that have a 2%
probability of exceedance in 50 years (2475 years return period). When integrated with the
ground motion hazard for the southern California site, the collapse probabilities result in mean
annual frequencies of collapse in the range of [0.4 to 1.4]x10
-4
for the various benchmark
building designs. In the development of these results, we made the following observations that
are expected to be broadly applicable:
(1) The ground motions selected for performance simulations must consider spectral
shape (e.g., through use of the epsilon parameter) and should appropriately account for
correlations between motions in both horizontal directions;
(2) Lower-bound component models, which are commonly used in performance-based
assessment procedures such as FEMA 356, can significantly bias collapse analysis results; it is
more appropriate to use median component behavior, including all aspects of the component
model (strength, stiffness, deformation capacity, cyclic deterioration, etc.);
(3) Structural modeling uncertainties related to component deformation capacity and
post-peak degrading stiffness can impact the variability of calculated collapse probabilities and
mean annual rates to a similar degree as record-to-record variability of ground motions.
Therefore, including the effects of such structural modeling uncertainties significantly increases
the mean annual collapse rates. We found this increase to be roughly four to eight times relative
to rates evaluated for the median structural model;
(4) Nonlinear response analyses revealed at least six distinct collapse mechanisms, the
most common of which was a story mechanism in the third story (differing from the multi-story
mechanism predicted by nonlinear static pushover analysis);
(5) Soil-foundation-structure interaction effects did not significantly affect the structural
response, which was expected given the relatively flexible superstructure and stiff soils.
The potential for financial loss is considerable. Overall, the calculated expected annual
losses (EAL) are in the range of 97,000 for the various code-conforming benchmark
building designs, or roughly 1% of the replacement cost of the building (3.5M, the fatality rate translates to an EAL due to
fatalities of 5,600 for the code-conforming designs, and 66,000, the monetary value associated with life loss is small,
suggesting that the governing factor in this respect will be the maximum permissible life-safety
risk deemed by the public (or its representative government) to be appropriate for buildings.
Although the focus of this report is on one specific building, it can be used as a reference
for other types of structures. This report is organized in such a way that the individual core
chapters (4, 5, and 6) can be read independently. Chapter 1 provides background on the
performance-based earthquake engineering (PBEE) approach. Chapter 2 presents the
implementation of the PBEE methodology of the PEER framework, as applied to the benchmark
building. Chapter 3 sets the stage for the choices of location and basic structural design. The subsequent core chapters focus on the hazard analysis (Chapter 4), the structural analysis
(Chapter 5), and the damage and loss analyses (Chapter 6). Although the report is self-contained,
readers interested in additional details can find them in the appendices
LSST: from Science Drivers to Reference Design and Anticipated Data Products
(Abridged) We describe here the most ambitious survey currently planned in
the optical, the Large Synoptic Survey Telescope (LSST). A vast array of
science will be enabled by a single wide-deep-fast sky survey, and LSST will
have unique survey capability in the faint time domain. The LSST design is
driven by four main science themes: probing dark energy and dark matter, taking
an inventory of the Solar System, exploring the transient optical sky, and
mapping the Milky Way. LSST will be a wide-field ground-based system sited at
Cerro Pach\'{o}n in northern Chile. The telescope will have an 8.4 m (6.5 m
effective) primary mirror, a 9.6 deg field of view, and a 3.2 Gigapixel
camera. The standard observing sequence will consist of pairs of 15-second
exposures in a given field, with two such visits in each pointing in a given
night. With these repeats, the LSST system is capable of imaging about 10,000
square degrees of sky in a single filter in three nights. The typical 5
point-source depth in a single visit in will be (AB). The
project is in the construction phase and will begin regular survey operations
by 2022. The survey area will be contained within 30,000 deg with
, and will be imaged multiple times in six bands, ,
covering the wavelength range 320--1050 nm. About 90\% of the observing time
will be devoted to a deep-wide-fast survey mode which will uniformly observe a
18,000 deg region about 800 times (summed over all six bands) during the
anticipated 10 years of operations, and yield a coadded map to . The
remaining 10\% of the observing time will be allocated to projects such as a
Very Deep and Fast time domain survey. The goal is to make LSST data products,
including a relational database of about 32 trillion observations of 40 billion
objects, available to the public and scientists around the world.Comment: 57 pages, 32 color figures, version with high-resolution figures
available from https://www.lsst.org/overvie
Drought: Economic Consequences and Policies for Mitigation Global Overview
The natural variation in climate around the world means that periods of severe shortfall of rainfall are inevitable, and some times occur on a large geographical scale. Human settlements have adapted to this reality in many different ways, including the development of agricultural systems that feature variously robust aspects in the face of drought. As climates change under the influence of modified atmospheric composition, it seems likely that many parts of the world will face increased incidence of drought and thus more challenging tasks for farm managers, managers of non- farm enterprises that are sensitive to drought, national policy makers and, last but not least, households in rural areas that are close to subsistence levels even in non-drought seasons. The agricultural economics profession must continue to contribute to better dealing with all these challenges.Environmental Economics and Policy,
Assistive technology design and development for acceptable robotics companions for ageing years
© 2013 Farshid Amirabdollahian et al., licensee Versita Sp. z o. o. This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivs license, which means that the text may be used for non-commercial purposes, provided credit is given to the author.A new stream of research and development responds to changes in life expectancy across the world. It includes technologies which enhance well-being of individuals, specifically for older people. The ACCOMPANY project focuses on home companion technologies and issues surrounding technology development for assistive purposes. The project responds to some overlooked aspects of technology design, divided into multiple areas such as empathic and social human-robot interaction, robot learning and memory visualisation, and monitoring persons’ activities at home. To bring these aspects together, a dedicated task is identified to ensure technological integration of these multiple approaches on an existing robotic platform, Care-O-Bot®3 in the context of a smart-home environment utilising a multitude of sensor arrays. Formative and summative evaluation cycles are then used to assess the emerging prototype towards identifying acceptable behaviours and roles for the robot, for example role as a butler or a trainer, while also comparing user requirements to achieved progress. In a novel approach, the project considers ethical concerns and by highlighting principles such as autonomy, independence, enablement, safety and privacy, it embarks on providing a discussion medium where user views on these principles and the existing tension between some of these principles, for example tension between privacy and autonomy over safety, can be captured and considered in design cycles and throughout project developmentsPeer reviewe
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