Evaluation of Cycle Life and Characterization of YTP 45 Ah Li-Ion Battery for EMU

NASA Technical Reports Server (NTRS)

Deng, Yi; Jeevarajan, Judith; Rehm, Raymond; Bragg, Bobby; Strangways, Brad

2002-01-01

Li-ion batteries, with longer cycle life and higher energy density features, are now more and more attractive and applied in multiple fields. The YTP 45 Ah Li-ion battery has been evaluated here and may be employed in EMU in the future. Evaluations were on: (1) Cycle life tests - 500 cycles total (completed 40 cycles in simulated shuttle use mode and 460 cycles in an accelerated use mode, and recorded differential voltage of individual cell in battery); (2) Characterization test - discharge capacity measurement in environment temperature of -10, 25, 50 C before and after 500 cycles; and (3) Thermal testing - charge and discharge at 50 C and -10 C before and after 500 cycles. The battery showed less than a 9% drop of initial discharge capacity and energy within 500 cycles with 475 cycles 59% DOD plus 25 cycles 100% DOD. The EOD voltage ranged from 16.0 to 18.0 V, which fits the requirement for operating the EMU.

Software engineering and simulation

NASA Technical Reports Server (NTRS)

Zhang, Shou X.; Schroer, Bernard J.; Messimer, Sherri L.; Tseng, Fan T.

1990-01-01

This paper summarizes the development of several automatic programming systems for discrete event simulation. Emphasis is given on the model development, or problem definition, and the model writing phases of the modeling life cycle.

Proof test and fatigue crack growth modeling on 2024-T3 aluminum alloy

NASA Technical Reports Server (NTRS)

Newman, J. C., Jr.; Poe, C. C., Jr.; Dawicke, D. S.

1990-01-01

Pressure proof testing of aircraft fuselage structures has been suggested as a means of screening critical crack sizes and of extending their useful life. The objective of this paper is to study the proof-test concept and to model the crack-growth process on a ductile material. Simulated proof and operational fatigue life tests have been conducted on cracked panels made of 2024-T3 aluminum alloy sheet material. A fatigue crack-closure model was modified to simulate the proof test and operational fatigue cycling. Using crack-growth rate and resistance-curve data, the model was able to predict crack growth during and after the proof load. These tests and analyses indicate that the proof test increases fatigue life; but the beneficial life, after a 1.33 or 1.5 proof, was less than a few hundred cycles.

Life cycle assessment framework of traffic systems based on microscopic simulation.

DOT National Transportation Integrated Search

2014-03-01

Transportation is an important infrastructure process needed in many steps of the supply chain of any product. Transportation-associated global impacts are therefore important factor influencing the sustainability of any product cycle. Moreover, traf...

The numerical high cycle fatigue damage model of fillet weld joint under weld-induced residual stresses

NASA Astrophysics Data System (ADS)

Nguyen Van Do, Vuong

2018-04-01

In this study, a development of nonlinear continuum damage mechanics (CDM) model for multiaxial high cycle fatigue is proposed in which the cyclic plasticity constitutive model has been incorporated in the finite element (FE) framework. T-joint FE simulation of fillet welding is implemented to characterize sequentially coupled three-dimensional (3-D) of thermo-mechanical FE formulation and simulate the welding residual stresses. The high cycle fatigue damage model is then taken account into the fillet weld joints under the various cyclic fatigue load types to calculate the fatigue life considering the residual stresses. The fatigue crack initiation and the propagation in the present model estimated for the total fatigue is compared with the experimental results. The FE results illustrated that the proposed high cycle fatigue damage model in this study could become a powerful tool to effectively predict the fatigue life of the welds. Parametric studies in this work are also demonstrated that the welding residual stresses cannot be ignored in the computation of the fatigue life of welded structures.

Advanced Training Techniques Using Computer Generated Imagery.

DTIC Science & Technology

1981-09-15

Annual Technical Report for Period- 16 May 1980 - 15 July 1981 LJ Prepared for AIR FORCE OFFICE OF SCIENTIFIC RESEARCH Director of Life Sciences Building...Simulation Management Branch, ATC, Randolph AFB, TX 78148, November 1977. Allbee, K. F., Semple C. A.; Aircrew Training Devices Life Cycle Cost and Worth...in Simulator Design and Application, Life Sciences, Inc., 227 Lood 820 NE, Hurst, Texas 76053, AFOSR-TR-77- 0965, 30 September 1976 McDonnell Aircraft

On the Use of Equivalent Linearization for High-Cycle Fatigue Analysis of Geometrically Nonlinear Structures

NASA Technical Reports Server (NTRS)

Rizzi, Stephen A.

2003-01-01

The use of stress predictions from equivalent linearization analyses in the computation of high-cycle fatigue life is examined. Stresses so obtained differ in behavior from the fully nonlinear analysis in both spectral shape and amplitude. Consequently, fatigue life predictions made using this data will be affected. Comparisons of fatigue life predictions based upon the stress response obtained from equivalent linear and numerical simulation analyses are made to determine the range over which the equivalent linear analysis is applicable.

Recurrent bottlenecks in the malaria life cycle obscure signals of positive selection.

PubMed

Chang, Hsiao-Han; Hartl, Daniel L

2015-02-01

Detecting signals of selection in the genome of malaria parasites is a key to identify targets for drug and vaccine development. Malaria parasites have a unique life cycle alternating between vector and host organism with a population bottleneck at each transition. These recurrent bottlenecks could influence the patterns of genetic diversity and the power of existing population genetic tools to identify sites under positive selection. We therefore simulated the site-frequency spectrum of a beneficial mutant allele through time under the malaria life cycle. We investigated the power of current population genetic methods to detect positive selection based on the site-frequency spectrum as well as temporal changes in allele frequency. We found that a within-host selective advantage is difficult to detect using these methods. Although a between-host transmission advantage could be detected, the power is decreased when compared with the classical Wright-Fisher (WF) population model. Using an adjusted null site-frequency spectrum that takes the malaria life cycle into account, the power of tests based on the site-frequency spectrum to detect positive selection is greatly improved. Our study demonstrates the importance of considering the life cycle in genetic analysis, especially in parasites with complex life cycles.

Life Span as the Measure of Performance and Learning in a Business Gaming Simulation

ERIC Educational Resources Information Center

Thavikulwat, Precha

2012-01-01

This study applies the learning curve method of measuring learning to participants of a computer-assisted business gaming simulation that includes a multiple-life-cycle feature. The study involved 249 participants. It verified the workability of the feature and estimated the participants' rate of learning at 17.4% for every doubling of experience.…

Electric/Hybrid Vehicle Simulation

NASA Technical Reports Server (NTRS)

Slusser, R. A.; Chapman, C. P.; Brennand, J. P.

1985-01-01

ELVEC computer program provides vehicle designer with simulation tool for detailed studies of electric and hybrid vehicle performance and cost. ELVEC simulates performance of user-specified electric or hybrid vehicle under user specified driving schedule profile or operating schedule. ELVEC performs vehicle design and life cycle cost analysis.

A Holistic Approach to Systems Development

NASA Technical Reports Server (NTRS)

Wong, Douglas T.

2008-01-01

Introduces a Holistic and Iterative Design Process. Continuous process but can be loosely divided into four stages. More effort spent early on in the design. Human-centered and Multidisciplinary. Emphasis on Life-Cycle Cost. Extensive use of modeling, simulation, mockups, human subjects, and proven technologies. Human-centered design doesn t mean the human factors discipline is the most important Disciplines should be involved in the design: Subsystem vendors, configuration management, operations research, manufacturing engineering, simulation/modeling, cost engineering, hardware engineering, software engineering, test and evaluation, human factors, electromagnetic compatibility, integrated logistics support, reliability/maintainability/availability, safety engineering, test equipment, training systems, design-to-cost, life cycle cost, application engineering etc. 9

Computer-aided software development process design

NASA Technical Reports Server (NTRS)

Lin, Chi Y.; Levary, Reuven R.

1989-01-01

The authors describe an intelligent tool designed to aid managers of software development projects in planning, managing, and controlling the development process of medium- to large-scale software projects. Its purpose is to reduce uncertainties in the budget, personnel, and schedule planning of software development projects. It is based on dynamic model for the software development and maintenance life-cycle process. This dynamic process is composed of a number of time-varying, interacting developmental phases, each characterized by its intended functions and requirements. System dynamics is used as a modeling methodology. The resulting Software LIfe-Cycle Simulator (SLICS) and the hybrid expert simulation system of which it is a subsystem are described.

Air Force Systems Engineering Assessment Model (AF SEAM) Management Guide, Version 2

DTIC Science & Technology

2010-09-21

gleaned from experienced professionals who assisted with the model’s development. Examples of the references used include the following: • ISO /IEC...Defense Acquisition Guidebook, Chapter 4 • AFI 63-1201, Life Cycle Systems Engineering • IEEE/EIA 12207 , Software Life Cycle Processes • Air...Selection criteria Reference Material: IEEE/EIA 12207 , MIL-HDBK-514 Other Considerations: Modeling, simulation and analysis techniques can be

Software life cycle dynamic simulation model: The organizational performance submodel

NASA Technical Reports Server (NTRS)

Tausworthe, Robert C.

1985-01-01

The submodel structure of a software life cycle dynamic simulation model is described. The software process is divided into seven phases, each with product, staff, and funding flows. The model is subdivided into an organizational response submodel, a management submodel, a management influence interface, and a model analyst interface. The concentration here is on the organizational response model, which simulates the performance characteristics of a software development subject to external and internal influences. These influences emanate from two sources: the model analyst interface, which configures the model to simulate the response of an implementing organization subject to its own internal influences, and the management submodel that exerts external dynamic control over the production process. A complete characterization is given of the organizational response submodel in the form of parameterized differential equations governing product, staffing, and funding levels. The parameter values and functions are allocated to the two interfaces.

Open Screw Placement in a 1.5 mm LCP Over a Fracture Gap Decreases Fatigue Life

PubMed Central

Alwen, Sarah G. J.; Kapatkin, Amy S.; Garcia, Tanya C.; Milgram, Joshua; Stover, Susan M.

2018-01-01

Objective To investigate the influence of plate and screw hole position on the stability of simulated radial fractures stabilized with a 1.5 mm condylar locking compression plate (LCP). Study Design In vitro mechanical testing of paired cadaveric limbs. Sample Population Paired radii (n = 7) stabilized with a 1.5 mm condylar LCP with an open screw hole positioned either proximal to (PG), or over (OG), a simulated small fracture gap. Methods Constructs were cycled in axial compression at a simulated trot load until failure or a maximum of 200,000 cycles. Specimens that sustained 200,000 cycles without failure were then loaded in axial compression in a single cycle to failure. Construct cyclic axial stiffness and gap strain, fatigue life, and residual strength were evaluated and compared between constructs using analysis of variance. Results Of pairs that had a failure during cyclic loading, OG constructs survived fewer cycles (54,700 ± 60,600) than PG (116,800 ± 49,300). OG constructs had significantly lower initial stiffness throughout cyclic loading and higher gap strain range within the first 1,000 cycles than PG constructs. Residual strength variables were not significantly different between constructs, however yield loads occurred at loads only marginally higher than approximated trot loads. Fatigue life decreased with increasing body weight. Conclusion Fracture fixation stability is compromised by an open screw hole directly over a fracture gap compared to the open screw hole being buttressed by bone in the model studied. The 1.5 mm condylar LCP may be insufficient stabilization in dogs with appropriate radial geometry but high body weights. PMID:29876361

The tropopause inversion layer at midlatitudes: Formation processes and relation to stratosphere-troposphere exchange

NASA Astrophysics Data System (ADS)

Kunkel, D.; Hoor, P. M.; Wirth, V.

2016-12-01

Recent studies revealed the existence of a quasi-permanent layer of enhanced static stability above the thermal tropopause. This so-called tropopause inversion layer (TIL) is evident in adiabatic baroclinic life cycles suggesting that dry dynamics contribute to its formation. However, compared to observations the TIL in these life cycles is too weak, indicating that other contributions from diabatic processes are relevant. Such processes could be related to moisture or radiation, or other non-linear, subgrid-scale processes such as gravity wave breaking. Moreover, whether there is a causal relation between the occurrence of the TIL and stratosphere-troposphere exchange (STE) is still under debate. In this study various types of baroclinic life cycles are simulated using a non-hydrostatic model in an idealized mid-latitude channel configuration. A simulation using only the dynamical core of the model serves as base simulation, which is modified subsequently by adding different processes. First, these processes such as vertical turbulence, cloud microphysics, radiation as well as surface fluxes for heat and momentum are added individually. In a second set of simulations combinations of these processes are studied to assess the relative importance of the individual processes in the formation of the TIL. Finally, the static stability is analyzed in regions of STE. These regions are identified with the help of passive tracer as well as a Lagrangian trajectory analysis.

Policy implications of uncertainty in modeled life-cycle greenhouse gas emissions of biofuels.

PubMed

Mullins, Kimberley A; Griffin, W Michael; Matthews, H Scott

2011-01-01

Biofuels have received legislative support recently in California's Low-Carbon Fuel Standard and the Federal Energy Independence and Security Act. Both present new fuel types, but neither provides methodological guidelines for dealing with the inherent uncertainty in evaluating their potential life-cycle greenhouse gas emissions. Emissions reductions are based on point estimates only. This work demonstrates the use of Monte Carlo simulation to estimate life-cycle emissions distributions from ethanol and butanol from corn or switchgrass. Life-cycle emissions distributions for each feedstock and fuel pairing modeled span an order of magnitude or more. Using a streamlined life-cycle assessment, corn ethanol emissions range from 50 to 250 g CO(2)e/MJ, for example, and each feedstock-fuel pathway studied shows some probability of greater emissions than a distribution for gasoline. Potential GHG emissions reductions from displacing fossil fuels with biofuels are difficult to forecast given this high degree of uncertainty in life-cycle emissions. This uncertainty is driven by the importance and uncertainty of indirect land use change emissions. Incorporating uncertainty in the decision making process can illuminate the risks of policy failure (e.g., increased emissions), and a calculated risk of failure due to uncertainty can be used to inform more appropriate reduction targets in future biofuel policies.

System Simulation Modeling: A Case Study Illustration of the Model Development Life Cycle

Treesearch

Janice K. Wiedenbeck; D. Earl Kline

1994-01-01

Systems simulation modeling techniques offer a method of representing the individual elements of a manufacturing system and their interactions. By developing and experimenting with simulation models, one can obtain a better understanding of the overall physical system. Forest products industries are beginning to understand the importance of simulation modeling to help...

Time matters--realism in resuscitation training.

PubMed

Krogh, Kristian B; Høyer, Christian B; Ostergaard, Doris; Eika, Berit

2014-08-01

The advanced life support guidelines recommend 2min of cardiopulmonary resuscitation (CPR) and minimal hands-off time to ensure sufficient cardiac and cerebral perfusion. We have observed doctors who shorten the CPR intervals during resuscitation attempts. During simulation-based resuscitation training, the recommended 2-min CPR cycles are often deliberately decreased in order to increase the number of scenarios. The aim of this study was to test if keeping 2-min CPR cycles during resuscitation training ensures better adherence to time during resuscitation in a simulated setting. This study was designed as a randomised control trial. Fifty-four 4th-year medical students with no prior advanced resuscitation training participated in an extra-curricular one-day advanced life support course. Participants were either randomised to simulation-based training using real-time (120s) or shortened CPR cycles (30-45s instead of 120s) in the scenarios. Adherence to time was measured using the European Resuscitation Council's Cardiac Arrest Simulation Test (CASTest) in retention tests conducted one and 12 weeks after the course. The real-time group adhered significantly better to the recommended 2-min CPR cycles (time-120s) (mean 13; standard derivation (SD) 8) than the shortened CPR cycle group (mean 45; SD 19) when tested (p<0.001.) This study indicates that time is an important part of fidelity. Variables critical for performance, like adherence to time in resuscitation, should therefore be kept realistic during training to optimise outcome. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

Whole life cycle of femtosecond ultraviolet filaments in water

NASA Astrophysics Data System (ADS)

Jarnac, Amélie; Tamosauskas, Gintaras; Majus, Donatas; Houard, Aurélien; Mysyrowicz, André; Couairon, Arnaud; Dubietis, Audrius

2014-03-01

We present measurements fully characterizing the whole life cycle of femtosecond pulses undergoing filamentation in water at 400 nm. The complete pulse dynamics is monitored by means of a four-dimensional mapping technique for the intensity distribution I (x,y,z,t) during the nonlinear interaction. Measured events (focusing or defocusing cycles, pulse splitting and replenishment, supercontinuum generation, conical emission, nonlinear absorption peaks) are mutually connected.The filament evolution from laser energy deposition in water, which is of paramount importance for a wide range of technological and medical applications, is interpreted in light of simulation results.

Life-cycle costs of high-performance cells

NASA Technical Reports Server (NTRS)

Daniel, R.; Burger, D.; Reiter, L.

1985-01-01

A life cycle cost analysis of high efficiency cells was presented. Although high efficiency cells produce more power, they also cost more to make and are more susceptible to array hot-spot heating. Three different computer analysis programs were used: SAMICS (solar array manufacturing industry costing standards), PVARRAY (an array failure mode/degradation simulator), and LCP (lifetime cost and performance). The high efficiency cell modules were found to be more economical in this study, but parallel redundancy is recommended.

Improved Environmental Life Cycle Assessment of Crop Production at the Catchment Scale via a Process-Based Nitrogen Simulation Model.

PubMed

Liao, Wenjie; van der Werf, Hayo M G; Salmon-Monviola, Jordy

2015-09-15

One of the major challenges in environmental life cycle assessment (LCA) of crop production is the nonlinearity between nitrogen (N) fertilizer inputs and on-site N emissions resulting from complex biogeochemical processes. A few studies have addressed this nonlinearity by combining process-based N simulation models with LCA, but none accounted for nitrate (NO3(-)) flows across fields. In this study, we present a new method, TNT2-LCA, that couples the topography-based simulation of nitrogen transfer and transformation (TNT2) model with LCA, and compare the new method with a current LCA method based on a French life cycle inventory database. Application of the two methods to a case study of crop production in a catchment in France showed that, compared to the current method, TNT2-LCA allows delineation of more appropriate temporal limits when developing data for on-site N emissions associated with specific crops in this catchment. It also improves estimates of NO3(-) emissions by better consideration of agricultural practices, soil-climatic conditions, and spatial interactions of NO3(-) flows across fields, and by providing predicted crop yield. The new method presented in this study provides improved LCA of crop production at the catchment scale.

Thermal fatigue life evaluation of SnAgCu solder joints in a multi-chip power module

NASA Astrophysics Data System (ADS)

Barbagallo, C.; Malgioglio, G. L.; Petrone, G.; Cammarata, G.

2017-05-01

For power devices, the reliability of thermal fatigue induced by thermal cycling has been prioritized as an important concern. The main target of this work is to apply a numerical procedure to assess the fatigue life for lead-free solder joints, that represent, in general, the weakest part of the electronic modules. Starting from a real multi-chip power module, FE-based models were built-up by considering different conditions in model implementation in order to simulate, from one hand, the worst working condition for the module and, from another one, the module standing into a climatic test room performing thermal cycles. Simulations were carried-out both in steady and transient conditions in order to estimate the module thermal maps, the stress-strain distributions, the effective plastic strain distributions and finally to assess the number of cycles to failure of the constitutive solder layers.

Design of a solar array simulator for the NASA EOS testbed

NASA Technical Reports Server (NTRS)

Butler, Steve J.; Sable, Dan M.; Lee, Fred C.; Cho, Bo H.

1992-01-01

The present spacecraft solar array simulator addresses both dc and ac characteristics as well as changes in illumination and temperature and performance degradation over the course of array service life. The computerized control system used allows simulation of a complete orbit cycle, in addition to automated diagnostics. The simulator is currently interfaced with the NASA EOS testbed.

Delving into sensible measures to enhance the environmental performance of biohydrogen: A quantitative approach based on process simulation, life cycle assessment and data envelopment analysis.

PubMed

Martín-Gamboa, Mario; Iribarren, Diego; Susmozas, Ana; Dufour, Javier

2016-08-01

A novel approach is developed to evaluate quantitatively the influence of operational inefficiency in biomass production on the life-cycle performance of hydrogen from biomass gasification. Vine-growers and process simulation are used as key sources of inventory data. The life cycle assessment of biohydrogen according to current agricultural practices for biomass production is performed, as well as that of target biohydrogen according to agricultural practices optimised through data envelopment analysis. Only 20% of the vineyards assessed operate efficiently, and the benchmarked reduction percentages of operational inputs range from 45% to 73% in the average vineyard. The fulfilment of operational benchmarks avoiding irregular agricultural practices is concluded to improve significantly the environmental profile of biohydrogen (e.g., impact reductions above 40% for eco-toxicity and global warming). Finally, it is shown that this type of bioenergy system can be an excellent replacement for conventional hydrogen in terms of global warming and non-renewable energy demand. Copyright © 2016 Elsevier Ltd. All rights reserved.

Life cycle, techno-economic and dynamic simulation assessment of bioelectrochemical systems: A case of formic acid synthesis.

PubMed

Shemfe, Mobolaji; Gadkari, Siddharth; Yu, Eileen; Rasul, Shahid; Scott, Keith; Head, Ian M; Gu, Sai; Sadhukhan, Jhuma

2018-05-01

A novel framework, integrating dynamic simulation (DS), life cycle assessment (LCA) and techno-economic assessment (TEA) of a bioelectrochemical system (BES), has been developed to study for the first time wastewater treatment by removal of chemical oxygen demand (COD) by oxidation in anode and thereby harvesting electron and proton for carbon dioxide reduction reaction or reuse to produce products in cathode. Increases in initial COD and applied potential increase COD removal and production (in this case formic acid) rates. DS correlations are used in LCA and TEA for holistic performance analyses. The cost of production of HCOOH is €0.015-0.005 g -1 for its production rate of 0.094-0.26 kg yr -1 and a COD removal rate of 0.038-0.106 kg yr -1 . The life cycle (LC) benefits by avoiding fossil-based formic acid production (93%) and electricity for wastewater treatment (12%) outweigh LC costs of operation and assemblage of BES (-5%), giving a net 61MJkg -1 HCOOH saving. Copyright © 2018 The Authors. Published by Elsevier Ltd.. All rights reserved.

Characterizing model uncertainties in the life cycle of lignocellulose-based ethanol fuels.

PubMed

Spatari, Sabrina; MacLean, Heather L

2010-11-15

Renewable and low carbon fuel standards being developed at federal and state levels require an estimation of the life cycle carbon intensity (LCCI) of candidate fuels that can substitute for gasoline, such as second generation bioethanol. Estimating the LCCI of such fuels with a high degree of confidence requires the use of probabilistic methods to account for known sources of uncertainty. We construct life cycle models for the bioconversion of agricultural residue (corn stover) and energy crops (switchgrass) and explicitly examine uncertainty using Monte Carlo simulation. Using statistical methods to identify significant model variables from public data sets and Aspen Plus chemical process models,we estimate stochastic life cycle greenhouse gas (GHG) emissions for the two feedstocks combined with two promising fuel conversion technologies. The approach can be generalized to other biofuel systems. Our results show potentially high and uncertain GHG emissions for switchgrass-ethanol due to uncertain CO₂ flux from land use change and N₂O flux from N fertilizer. However, corn stover-ethanol,with its low-in-magnitude, tight-in-spread LCCI distribution, shows considerable promise for reducing life cycle GHG emissions relative to gasoline and corn-ethanol. Coproducts are important for reducing the LCCI of all ethanol fuels we examine.

From individual to population level effects of toxicants in the tubicifid Branchiura sowerbyi using threshold effect models in a Bayesian framework.

PubMed

Ducrot, Virginie; Billoir, Elise; Péry, Alexandre R R; Garric, Jeanne; Charles, Sandrine

2010-05-01

Effects of zinc were studied in the freshwater worm Branchiura sowerbyi using partial and full life-cycle tests. Only newborn and juveniles were sensitive to zinc, displaying effects on survival, growth, and age at first brood at environmentally relevant concentrations. Threshold effect models were proposed to assess toxic effects on individuals. They were fitted to life-cycle test data using Bayesian inference and adequately described life-history trait data in exposed organisms. The daily asymptotic growth rate of theoretical populations was then simulated with a matrix population model, based upon individual-level outputs. Population-level outputs were in accordance with existing literature for controls. Working in a Bayesian framework allowed incorporating parameter uncertainty in the simulation of the population-level response to zinc exposure, thus increasing the relevance of test results in the context of ecological risk assessment.

Shallow cloud statistics over Tropical Western Pacific: CAM5 versus ARM Comparison

NASA Astrophysics Data System (ADS)

Chandra, A.; Zhang, C.; Klein, S. A.; Ma, H. Y.; Kollias, P.; Xie, S.

2014-12-01

The role of shallow convection in the tropical convective cloud life cycle has received increasing interest because of its sensitivity to simulate large-scale tropical disturbances such as MJO. Though previous studies have proposed several hypotheses to explain the role of shallow clouds in the convective life cycle, our understanding on the role of shallow clouds is still premature. There are more questions needs to be addressed related to the role of different cloud population, conditions favorable for shallow to deep convection transitions, and their characteristics at different stages of the convective cloud life. The present study aims to improve the understanding of the shallow clouds by documenting the role of different shallow cloud population for the Year of Tropical Convection period using Atmospheric Radiation Measurement observations at the Tropical Western Pacific Manus site. The performance of the CAM5 model to simulate shallow clouds are tested using observed cloud statistics.

On the life cycle cost and return on investment of a 500 GW global space solar power system

NASA Astrophysics Data System (ADS)

Koelle, H. H.

Past studies have produced considerable evidence that Peter E. Glaser's proposal to establish solar power plants in the geostationary orbit (to contribute to the supply of our planet with electrical energy) is technically feasible. However, the economical viability and the risks involved were hurdles to be taken. A new reference system using chemical propellants only and lunar resources seem to provide satisfactory answers with respect to economy and risk. Detailed simulations of this new reference concept through a full life cycle provide new insights which are reason enough to encourage further analysis. Data on a 500 GW SSPS system and its technical and financial properties over a 14 year development and 100 year operational life cycle are presented on 24 diagrams.

On the life cycle cost and return on investment of a 500 GW global space solar power system

NASA Astrophysics Data System (ADS)

Koelle, H. H.

1987-10-01

Past studies have produced considerable evidence that Glaser's (1968 and 1973) proposal to establish solar powerplants in the geostationary orbit (to contribute to the supply of our planet with electrical energy) is technically feasible. However, the economical viability and the risks involved were hurdles to be taken. A new reference system using chemical propellants only and lunar resources seem to provide satisfactory answers with respect to economy and risk. Detailed simulations of this new reference concept through a full life cycle provide new insights which are reason enough to encourage further analysis. Data on a 500 GW SSPS system and its technical and financial properties over a 14 year development and 100 year operational life cycle are presented on 24 diagrams.

Simulating anchovy's full life cycle in the northern Aegean Sea (eastern Mediterranean): A coupled hydro-biogeochemical-IBM model

NASA Astrophysics Data System (ADS)

Politikos, D.; Somarakis, S.; Tsiaras, K. P.; Giannoulaki, M.; Petihakis, G.; Machias, A.; Triantafyllou, G.

2015-11-01

A 3-D full life cycle population model for the North Aegean Sea (NAS) anchovy stock is presented. The model is two-way coupled with a hydrodynamic-biogeochemical model (POM-ERSEM). The anchovy life span is divided into seven life stages/age classes. Embryos and early larvae are passive particles, but subsequent stages exhibit active horizontal movements based on specific rules. A bioenergetics model simulates the growth in both the larval and juvenile/adult stages, while the microzooplankton and mesozooplankton fields of the biogeochemical model provide the food for fish consumption. The super-individual approach is adopted for the representation of the anchovy population. A dynamic egg production module, with an energy allocation algorithm, is embedded in the bioenergetics equation and produces eggs based on a new conceptual model for anchovy vitellogenesis. A model simulation for the period 2003-2006 with realistic initial conditions reproduced well the magnitude of population biomass and daily egg production estimated from acoustic and daily egg production method (DEPM) surveys, carried out in the NAS during June 2003-2006. Model simulated adult and egg habitats were also in good agreement with observed spatial distributions of acoustic biomass and egg abundance in June. Sensitivity simulations were performed to investigate the effect of different formulations adopted for key processes, such as reproduction and movement. The effect of the anchovy population on plankton dynamics was also investigated, by comparing simulations adopting a two-way or a one-way coupling of the fish with the biogeochemical model.

Applying Movement Ecology to Marine Animals with Complex Life Cycles.

PubMed

Allen, Richard M; Metaxas, Anna; Snelgrove, Paul V R

2018-01-03

Marine animals with complex life cycles may move passively or actively for fertilization, dispersal, predator avoidance, resource acquisition, and migration, and over scales from micrometers to thousands of kilometers. This diversity has catalyzed idiosyncratic and unfocused research, creating unsound paradigms regarding the role of movement in ecology and evolution. The emerging movement ecology paradigm offers a framework to consolidate movement research independent of taxon, life-history stage, scale, or discipline. This review applies the framework to movement among life-history stages in marine animals with complex life cycles to consolidate marine movement research and offer insights for scientists working in aquatic and terrestrial realms. Irrespective of data collection or simulation strategy, breaking each life-history stage down into the fundamental units of movement allows each unit to be studied independently or interactively with other units. Understanding these underlying mechanisms of movement within each life-history stage can then be used to construct lifetime movement paths. These paths can allow further investigation of the relative contributions and interdependencies of steps and phases across a lifetime and how these paths influence larger research topics, such as population-level movements.

Applying Movement Ecology to Marine Animals with Complex Life Cycles

NASA Astrophysics Data System (ADS)

Allen, Richard M.; Metaxas, Anna; Snelgrove, Paul V. R.

2018-01-01

Marine animals with complex life cycles may move passively or actively for fertilization, dispersal, predator avoidance, resource acquisition, and migration, and over scales from micrometers to thousands of kilometers. This diversity has catalyzed idiosyncratic and unfocused research, creating unsound paradigms regarding the role of movement in ecology and evolution. The emerging movement ecology paradigm offers a framework to consolidate movement research independent of taxon, life-history stage, scale, or discipline. This review applies the framework to movement among life-history stages in marine animals with complex life cycles to consolidate marine movement research and offer insights for scientists working in aquatic and terrestrial realms. Irrespective of data collection or simulation strategy, breaking each life-history stage down into the fundamental units of movement allows each unit to be studied independently or interactively with other units. Understanding these underlying mechanisms of movement within each life-history stage can then be used to construct lifetime movement paths. These paths can allow further investigation of the relative contributions and interdependencies of steps and phases across a lifetime and how these paths influence larger research topics, such as population-level movements.

Moist Baroclinic Life Cycles in an Idealized Model with Varying Hydrostasy

NASA Astrophysics Data System (ADS)

Hsieh, T. L.; Garner, S.; Held, I.

2016-12-01

Baroclinic life cycles are simulated in a limited-area model having varying degrees of hydrostasy to examine their interaction with explicitly resolved moist convection. The life cycles are driven by an idealized sea surface temperature field in an f-plane channel, and no convective parameterization is used. The hydrostasy is controlled by rescaling the model equations following the hypohydrostatic rescaling and by changing the resolution. In experiments having the same ratio between the grid spacing and the rescaling factor, the simulated convection is shown to have the same hydrostasy, suggesting that the low resolution models have been rescaled to be as nonhydrostatic as the high resolution model without additional computational cost. The nonhydrostatic convective cells in the rescaled models are found to be wider and slower than those in the unscaled models, consistent with predictions of the similarity theory. For the same resolution, although the wider cells in the rescaled models have better resolved structure, the total latent heating is insensitive to the rescaling factor. This is because latent heating is constrained by long-wave cooling which is found to be insensitive to the model hydrostasy, requiring a non-similarity in the frequency and distribution of convection. Consequently, the resolved nonhydrostatic convection maintains the same stability profile as the unresolved hydrostatic convection, so the statistics of the life cycles are also insensitive to the rescaling factor. The findings suggest that the mean climate and internal variability would be unaffected by the hypohydrostatic rescaling when the self-organization of convection is not important.

The effects of simulated bone loss on the implant-abutment assembly and likelihood of fracture: an in vitro study.

PubMed

Manzoor, Behzad; Suleiman, Mahmood; Palmer, Richard M

2013-01-01

The crestal bone level around a dental implant may influence its strength characteristics by offering protection against mechanical failures. Therefore, the present study investigated the effect of simulated bone loss on modes, loads, and cycles to failure in an in vitro model. Different amounts of bone loss were simulated: 0, 1.5, 3.0, and 4.5 mm from the implant head. Forty narrow-diameter (3.0-mm) implant-abutment assemblies were tested using compressive bending and cyclic fatigue testing. Weibull and accelerated life testing analysis were used to assess reliability and functional life. Statistical analyses were performed using the Fisher-Exact test and the Spearman ranked correlation. Compressive bending tests showed that the level of bone loss influenced the load-bearing capacity of implant-abutment assemblies. Fatigue testing showed that the modes, loads, and cycles to failure had a statistically significant relationship with the level of bone loss. All 16 samples with bone loss of 3.0 mm or more experienced horizontal implant body fractures. In contrast, 14 of 16 samples with 0 and 1.5 mm of bone loss showed abutment and screw fractures. Weibull and accelerated life testing analysis indicated a two-group distribution: the 0- and 1.5-mm bone loss samples had better functional life and reliability than the 3.0- and 4.5-mm samples. Progressive bone loss had a significant effect on modes, loads, and cycles to failure. In addition, bone loss influenced the functional life and reliability of the implant-abutment assemblies. Maintaining crestal bone levels is important in ensuring biomechanical sustainability and predictable long-term function of dental implant assemblies.

Assessment of the Neutronic and Fuel Cycle Performance of the Transatomic Power Molten Salt Reactor Design

DOE Office of Scientific and Technical Information (OSTI.GOV)

Robertson, Sean; Dewan, Leslie; Massie, Mark

This report presents results from a collaboration between Transatomic Power Corporation (TAP) and Oak Ridge National Laboratory (ORNL) to provide neutronic and fuel cycle analysis of the TAP core design through the Department of Energy Gateway for Accelerated Innovation in Nuclear (GAIN) Nuclear Energy Voucher program. The TAP concept is a molten salt reactor using configurable zirconium hydride moderator rod assemblies to shift the neutron spectrum in the core from mostly epithermal at beginning of life to thermal at end of life. Additional developments in the ChemTriton modeling and simulation tool provide the critical moderator-to-fuel ratio searches and time-dependent parametersmore » necessary to simulate the continuously changing physics in this complex system. The implementation of continuous-energy Monte Carlo transport and depletion tools in ChemTriton provide for full-core three-dimensional modeling and simulation. Results from simulations with these tools show agreement with TAP-calculated performance metrics for core lifetime, discharge burnup, and salt volume fraction, verifying the viability of reducing actinide waste production with this concept. Additional analyses of mass feed rates and enrichments, isotopic removals, tritium generation, core power distribution, core vessel helium generation, moderator rod heat deposition, and reactivity coeffcients provide additional information to make informed design decisions. This work demonstrates capabilities of ORNL modeling and simulation tools for neutronic and fuel cycle analysis of molten salt reactor concepts.« less

Emergence of life from multicomponent mixtures of chemicals: the case for experiments with cycling physicochemical gradients.

PubMed

Spitzer, Jan

2013-04-01

The emergence of life from planetary multicomponent mixtures of chemicals is arguably the most complicated and least understood natural phenomenon. The fact that living cells are non-equilibrium systems suggests that life can emerge only from non-equilibrium chemical systems. From an astrobiological standpoint, non-equilibrium chemical systems arise naturally when solar irradiation strikes rotating surfaces of habitable planets: the resulting cycling physicochemical gradients persistently drive planetary chemistries toward "embryonic" living systems and an eventual emergence of life. To better understand the factors that lead to the emergence of life, I argue for cycling non-equilibrium experiments with multicomponent chemical systems designed to represent the evolving chemistry of Hadean Earth ("prebiotic soups"). Specifically, I suggest experimentation with chemical engineering simulators of Hadean Earth to observe and analyze (i) the appearances and phase separations of surface active and polymeric materials as precursors of the first "cell envelopes" (membranes) and (ii) the accumulations, commingling, and co-reactivity of chemicals from atmospheric, oceanic, and terrestrial locations.

S.A.M., the Italian Martian Simulation Chamber

NASA Astrophysics Data System (ADS)

Galletta, G.; Ferri, F.; Fanti, G.; D'Alessandro, M.; Bertoloni, G.; Pavarin, D.; Bettanini, C.; Cozza, P.; Pretto, P.; Bianchini, G.; Debei, S.

2006-12-01

The Martian Environment Simulator (SAM “Simulatore di Ambiente Marziano”) is a interdisciplinary project of Astrobiology done at University of Padua. The research is aimed to the study of the survival of the microorganisms exposed to the “extreme” planetary environment. The facility has been designed in order to simulate Mars’ environmental conditions in terms of atmospheric pressure, temperature cycles and UV radiation dose. The bacterial cells, contained into dedicated capsules, will be exposed to thermal cycles simulating diurnal and seasonal Martian cycles. The metabolism of the different biological samples will be analysed at different phases of the experiment, to study their survival and eventual activity of protein synthesis (mortality, mutations and capability of DNA reparing). We describe the experimental facility and provide the perspectives of the biological experiments we will perform in order to provide hints on the possibility of life on Mars either autochthonous or imported from Earth.

Space Station Freedom NiH2 cell testing program

NASA Technical Reports Server (NTRS)

Moore, Bruce; Frate, Dave

1994-01-01

Testing for the Space Station Freedom Nickel Hydrogen Cell Test Program began in 1990 at Crave Division, Naval Surface Warfare Center. The program has included receipt inspection, random vibration, acceptance, characterization, and life cycle testing of Ni-H2 cells in accordance with the NASA LeRC Interagency Order C-31001-J. A total of 400 Ni-H2 cells have been received at NAVSURFWARCENDIV Crane from three separate manufacturers; Yardney Technical Products (Yardney), Eagle Picher Industries (Eagle Picher), and Gates Energy Products (Gates). Of those, 308 cells distributed among 39 packs have undergone life cycle testing under a test regime simulating low earth orbit conditions. As of 30 September 1993, there are 252 cells assembled into 32 packs still on life cycle test. Since the beginning of the program, failed cells have been detected in all phases of testing. The failures include the following; seven 65 AmpHr and 81 AmpHr Yardney cells were found to be leaking KOH on receipt, one 65 AmpHr Eagle Picher cell failed the acceptance test, one 65 AmpHr Gates cell failed during the characterization test, and six 65 AmpHr Gates cells failed the random vibration test. Of the 39 life cycle packs, testing on seven packs, 56 cells, has been suspended because of low end of discharge voltages. All of the failed life cycle packs were cycled at 60% depth of discharge.

Transport of Passive Tracers in Baroclinic Wave Life Cycles

NASA Technical Reports Server (NTRS)

Stone, Elizabeth M.; Randel, William J.; Stanford, John L.

1999-01-01

The transport of passive tracers in idealized baroclinic wave life cycles is studied using output from the National Center for Atmospheric Research Community Climate Model (CCM2). Two life cycles, LCn and LCs, are simulated, starting with baroclinically unstable initial conditions similar to those used by Thorncroft et al. in their study of two life cycle paradigms. The two life cycles LCn and LCs have different initial horizontal wind shear structures that result in distinctive nonlinear development. In terms of potential vorticity-potential temperature (PV-theta) diagnostics, the LCn case is characterized by thinning troughs that are advected anti-cyclonically and equatorward, while the LCs case has broadening troughs that wrap up cyclonically and poleward. Four idealized passive tracers are included in the model to be advected by the semi-Lagrangian transport scheme of the CCM2, and their evolutions are investigated throughout the life cycles. Tracer budgets are analyzed in terms of the transformed Eulerian mean constituent transport formalism in pressure coordinates and also in isentropic coordinates. Results for both LCn and LCs show transport that is downgradient with respect to the background structure of the tracer field, but with a characteristic spatial structure that maximizes in the middle to high latitudes. For the idealized tropospheric tracers in this study, this represents a net upward and poleward transport that enhances concentrations at high latitudes. These results vary little with the initial distribution of the constituent field. The time tendency of the tracer is influenced most strongly by the eddy flux term. with the largest transport occurring during the nonlinear growth stage of the life cycle. The authors also study the transport of a lower-stratospheric tracer, to examine stratosphere-troposphere exchange for baroclinic waves.

The Role of Gravity on the Reproduction of Arabidopsis Plants

NASA Technical Reports Server (NTRS)

Hoshizaki, T.

1985-01-01

The presence of gravity as a necessary environmental factor for higher plants to complete their life cycle was examined. Arabidopsis thalliana (L.) Heynh. Columbia strain plants were grown continuously for three generations in a simulated micro-g environment as induced by horizontal clinostats. Growth, development and reproduction were followed. The Arabidopsis plants were selected for three generations on clinostats because: (1) a short life cycle of around 35 days; (2) the cells of third generation plants would in theory be free of gravity imprint; and (3) a third generation plant would therefore more than likely grow and respond like a plant growing in a micro-g environment. It is found that gravity is not a required environmental factor for higher plants to complete their life cycle, at least as tested by a horizontal clinostat. Clinostatting does not prevent the completion of the plant life cycle. However, clinostatting does appear to slow down the reproductive process of Arabidopsis plants. Whether higher plants can continue to reproduce for many generations in a true micro-g environment of space can only be determined by long duration experiments in space.

EOS-AM1 Nickel Hydrogen Cell Interim Life Test Report

NASA Technical Reports Server (NTRS)

Bennett, C. W.; Keys, D. J.; Rao, G. M.; Wannemacher, H. E.; Vaidyanathan, H.

1997-01-01

This paper reports the interim results of the Earth Observing System AM-1 project (EOS-AM-1) nickel hydrogen cell life test being conducted under contract to National Aeronautics and Space Administration (NASA) Goddard Space Flight Center (GSFC) at the Lockheed Martin Missiles and Space (LMMS) facility in East Windsor, NJ; and at COMSAT Labs., Clarksburg, MD. The purpose of the tests is to verify that the EOS-AM-l cell design can meet five years of real-time Low Earth Orbit (LEO) cycling. The tests include both real-time LEO and accelerated stress tests. At LMMS, the first real-time LEO simulated 99 minute orbital cycle started on February 7, 1994 and the test has been running continuously since that time, with 13000 LEO cycles completed as of September 2, 1996. Each cycle consists of a 64 minute charge (VT at 1.507 volts per cell, 1.06 C/D ratio, followed by 0.6 ampere trickle charge) and a 35 minute constant power discharge at 177 watts (22.5% DOD). At COMSAT, the accelerated stress test consists of 90 minute orbital cycles at 60% DOD with a 30 minute discharge at 60 amperes and a 60 minute charge at 40 ampercs (VT at 1.54 volts per cell to 1.09 C/D ratio, followed by 0.6 ampere trickle charge). The real-time LEO life test battery consists of seven, 50AH (nameplate rating) Eagle-Picher, Inc. (EPI) Mantech cells manufactured into three, 3-cell pack assemblies (there are two place holder cells that are not part of the life test electrical circuit). The test pack is configured to simulate the conductive thermal design of the spacecraft battely, including: conductive aluminum sleeves, 3-cell pack aluminum baseplate, and honeycomb panel all mounted to a liquid (-5 C) cold plate. The entire assembly is located in a thermal chamber operating at +3 C. The accelerated stress test unit consists of five cells mounted in machined aluminum test sleeves and is operating at +10 C. The real-time LEO life test battery has met all performance requirements through the first 13,000 cycles, including: end of charge and discharge cell voltages and voltage gradients; end of chalge and discharge cell pressures; within cell and between cell temperature gradients; discharge capacity; current and power levels; and all chalge parameters. The accelerated stress test battely has completed over 5900 cycles as of 9/11/96. This paper reports both battery performances as a function of cycle life, with individual cell performance comparisons repolted for selected cycles in both tests.

Low-cycle fatigue testing methods

NASA Technical Reports Server (NTRS)

Lieurade, H. P.

1978-01-01

The good design of highly stressed mechanical components requires accurate knowledge of the service behavior of materials. The main methods for solving the problems of designers are: determination of the mechanical properties of the material after cyclic stabilization; plotting of resistance to plastic deformation curves; effect of temperature on the life on low cycle fatigue; and simulation of notched parts behavior.

NASA's Robotic Mining Competition Provides Undergraduates Full Life Cycle Systems Engineering Experience

NASA Technical Reports Server (NTRS)

Stecklein, Jonette

2017-01-01

NASA has held an annual robotic mining competition for teams of university/college students since 2010. This competition is yearlong, suitable for a senior university engineering capstone project. It encompasses the full project life cycle from ideation of a robot design, through tele-operation of the robot collecting regolith in simulated Mars conditions, to disposal of the robot systems after the competition. A major required element for this competition is a Systems Engineering Paper in which each team describes the systems engineering approaches used on their project. The score for the Systems Engineering Paper contributes 25% towards the team’s score for the competition’s grand prize. The required use of systems engineering on the project by this competition introduces the students to an intense practical application of systems engineering throughout a full project life cycle.

10 CFR 434.601 - General.

Code of Federal Regulations, 2010 CFR

2010-01-01

... a conventional simulation tool, of the Proposed Design. A life cycle cost analysis shall be used to select the fuel source for the HVAC systems, service hot water, and process loads from available...

Assessment of fatigue life of remanufactured impeller based on FEA

NASA Astrophysics Data System (ADS)

Xu, Lei; Cao, Huajun; Liu, Hailong; Zhang, Yubo

2016-09-01

Predicting the fatigue life of remanufactured centrifugal compressor impellers is a critical problem. In this paper, the S-N curve data were obtained by combining experimentation and theory deduction. The load spectrum was compiled by the rain-flow counting method based on the comprehensive consideration of the centrifugal force, residual stress, and aerodynamic loads in the repair region. A fatigue life simulation model was built, and fatigue life was analyzed based on the fatigue cumulative damage rule. Although incapable of providing a high-precision prediction, the simulation results were useful for the analysis of fatigue life impact factors and fatigue fracture areas. Results showed that the load amplitude greatly affected fatigue life, the impeller was protected from running at over-speed, and the predicted fatigue life was satisfied within the next service cycle safely at the rated speed.

Simulation of the M13 life cycle II: Investigation of the control mechanisms of M13 infection and establishment of the carrier state.

PubMed

Smeal, Steven W; Schmitt, Margaret A; Pereira, Ronnie Rodrigues; Prasad, Ashok; Fisk, John D

2017-01-01

Bacteriophage M13 is a true parasite of bacteria, able to co-opt the infected cell and control the production of progeny across many cellular generations. Here, our genetically-structured simulation of M13 is applied to quantitatively dissect the interplay between the host cellular environment and the controlling interactions governing the phage life cycle during the initial establishment of infection and across multiple cell generations. Multiple simulations suggest that phage-encoded feedback interactions constrain the utilization of host DNA polymerase, RNA polymerase and ribosomes. The simulation reveals the importance of p5 translational attenuation in controlling the production of phage double-stranded DNA and suggests an underappreciated role for p5 translational self-attenuation in resource allocation. The control elements active in a single generation are sufficient to reproduce the experimentally-observed multigenerational curing of the phage infection. Understanding the subtleties of regulation will be important for maximally exploiting M13 particles as scaffolds for nanoscale devices. Copyright © 2016 Elsevier Inc. All rights reserved.

Model-based verification and validation of the SMAP uplink processes

NASA Astrophysics Data System (ADS)

Khan, M. O.; Dubos, G. F.; Tirona, J.; Standley, S.

Model-Based Systems Engineering (MBSE) is being used increasingly within the spacecraft design community because of its benefits when compared to document-based approaches. As the complexity of projects expands dramatically with continually increasing computational power and technology infusion, the time and effort needed for verification and validation (V& V) increases geometrically. Using simulation to perform design validation with system-level models earlier in the life cycle stands to bridge the gap between design of the system (based on system-level requirements) and verifying those requirements/validating the system as a whole. This case study stands as an example of how a project can validate a system-level design earlier in the project life cycle than traditional V& V processes by using simulation on a system model. Specifically, this paper describes how simulation was added to a system model of the Soil Moisture Active-Passive (SMAP) mission's uplink process. Also discussed are the advantages and disadvantages of the methods employed and the lessons learned; which are intended to benefit future model-based and simulation-based development efforts.

Development and application of EEAST: a life cycle based model for use of harvested rainwater and composting toilets in buildings.

PubMed

Devkota, J; Schlachter, H; Anand, C; Phillips, R; Apul, Defne

2013-11-30

Harvested rainwater systems and composting toilets are expected to be an important part of sustainable solutions in buildings. Yet, to this date, a model evaluating their economic and environmental impact has been missing. To address this need, a life cycle based model, EEAST was developed. EEAST was designed to compare the business as usual (BAU) case of using potable water for toilet flushing and irrigation to alternative scenarios of rainwater harvesting and composting toilet based technologies. In EEAST, building characteristics, occupancy, and precipitation are used to size the harvested rainwater and composting toilet systems. Then, life cycle costing and life cycle assessment methods are used to estimate cost, energy, and greenhouse gas (GHG) emission payback periods (PPs) for five alternative scenarios. The scenarios modeled include use of harvested rainwater for toilet flushing, for irrigation, or both; and use of composting toilets with or without harvested rainwater use for irrigation. A sample simulation using EEAST showed that for the office building modeled, the cost PPs were greater than energy PPs which in turn were greater than GHG emission PPs. This was primarily due to energy and emission intensive nature of the centralized water and wastewater infrastructure. The sample simulation also suggested that the composting toilets may have the best performance in all criteria. However, EEAST does not explicitly model solids management and as such may give composting toilets an unfair advantage compared to flush based toilets. EEAST results were found to be very sensitive to cost values used in the model. With the availability of EEAST, life cycle cost, energy, and GHG emissions can now be performed fairly easily by building designers and researchers. Future work is recommended to further improve EEAST and evaluate it for different types of buildings and climates so as to better understand when composting toilets and harvested rainwater systems outperform the BAU case in building design. Copyright © 2013 Elsevier Ltd. All rights reserved.

Novel Electrochemical Test Bench for Evaluating the Functional Fatigue Life of Biomedical Alloys

NASA Astrophysics Data System (ADS)

Ijaz, M. F.; Dubinskiy, S.; Zhukova, Y.; Korobkova, A.; Pustov, Y.; Brailovski, V.; Prokoshkin, S.

2017-08-01

The aim of the present work was first to develop and validate a test bench that simulates the in vitro conditions to which the biomedical implants will be actually subjected in vivo. For the preliminary application assessments, the strain-controlled fatigue tests of biomedically pure Ti and Ti-Nb-Zr alloy in simulated body fluid were undertaken. The in situ open-circuit potential measurements from the test bench demonstrated a strong dependence on the dynamic cycling and kind of material under testing. The results showed that during fatigue cycling, the passive oxide film formed on the surface of Ti-Nb-Zr alloy was more resistant to fatigue degradation when compared with pure Ti. The Ti-Nb-Zr alloy exhibited prolonged fatigue life when compared with pure Ti. The fractographic features of both materials were also characterized using scanning electron microscopy. The electrochemical results and the fractographic evidence confirmed that the prolonged functional fatigue life of the Ti-Nb-Zr alloy is apparently ascribable to the reversible martensitic phase transformation.

A Continuous Labour Supply Model in Microsimulation: A Life-Cycle Modelling Approach with Heterogeneity and Uncertainty Extension

PubMed Central

Li, Jinjing; Sologon, Denisa Maria

2014-01-01

This paper advances a structural inter-temporal model of labour supply that is able to simulate the dynamics of labour supply in a continuous setting and addresses two main drawbacks of most existing models. The first limitation is the inability to incorporate individual heterogeneity as every agent is sharing the same parameters of the utility function. The second one is the strong assumption that individuals make decisions in a world of perfect certainty. Essentially, this paper offers an extension of marginal-utility-of-wealth-constant labour supply functions known as “Frisch functions” under certainty and uncertainty with homogenous and heterogeneous preferences. The lifetime models based on the fixed effect vector decomposition yield the most stable simulation results, under both certain and uncertain future wage assumptions. Due to its improved accuracy and stability, this lifetime labour supply model is particularly suitable for enhancing the performance of the life cycle simulation models, thus providing a better reference for policymaking. PMID:25391021

Modelling the pelagic nitrogen cycle and vertical particle flux in the Norwegian sea

NASA Astrophysics Data System (ADS)

Haupt, Olaf J.; Wolf, Uli; v. Bodungen, Bodo

1999-02-01

A 1D Eulerian ecosystem model (BIological Ocean Model) for the Norwegian Sea was developed to investigate the dynamics of pelagic ecosystems. The BIOM combines six biochemical compartments and simulates the annual nitrogen cycle with specific focus on production, modification and sedimentation of particles in the water column. The external forcing and physical framework is based on a simulated annual cycle of global radiation and an annual mixed-layer cycle derived from field data. The vertical resolution of the model is given by an exponential grid with 200 depth layers, allowing specific parameterization of various sinking velocities, breakdown of particles and the remineralization processes. The aim of the numerical experiments is the simulation of ecosystem dynamics considering the specific biogeochemical properties of the Norwegian Sea, for example the life cycle of the dominant copepod Calanus finmarchicus. The results of the simulations were validated with field data. Model results are in good agreement with field data for the lower trophic levels of the food web. With increasing complexity of the organisms the differences increase between simulated processes and field data. Results of the numerical simulations suggest that BIOM is well adapted to investigate a physically controlled ecosystem. The simulation of grazing controlled pelagic ecosystems, like the Norwegian Sea, requires adaptations of parameterization to the specific ecosystem features. By using seasonally adaptation of the most sensible processes like utilization of light by phytoplankton and grazing by zooplankton results were greatly improved.

A potential relation between stratosphere-troposphere exchange and the tropopause inversion layer in idealized baroclinic life cycle experiments

NASA Astrophysics Data System (ADS)

Kunkel, Daniel; Kaluza, Thorsten; Wirth, Volkmar; Hoor, Peter

2017-04-01

The tropopause inversion layer (TIL) as a well known feature of the lower stratosphere in the extratropics has often been suspected of impeding the exchange between stratospheric and tropospheric air masses (STE). However, it is still an open question whether a physical relation between STE and the TIL exists. We use a non-hydrostatic limited area model to simulate idealized baroclinic life cycles along with different diagnostics for STE such as Eulerian passive tracers and Lagrangian trajectories. Recent findings suggest a strenghtening of the TIL during such life cycles due to diabatic tropospheric processes as well as wave breaking. Moreover, STE also occurs frequently during such baroclinic life cycles, e.g., in the vicinity of tropopause folds, cut-off lows, or stratospheric streamers. Contradicting to current knowledge the analysis of static stability above the thermal tropopause and the identification of regions of STE show that a temporal and spatial co-location of a strong TIL and regions of transport from the troposphere into the stratosphere is possible. Evidence is further presented that such a co-location is related to tropospheric updrafts and small scale waves in the lower stratosphere. These findings are also supported by an analysis of baroclinic life cycles in high resolution operational analysis data from the European Center for Medium-Range Weather Forecasts (ECMWF).

A deterministic model of nettle caterpillar life cycle

NASA Astrophysics Data System (ADS)

Syukriyah, Y.; Nuraini, N.; Handayani, D.

2018-03-01

Palm oil is an excellent product in the plantation sector in Indonesia. The level of palm oil productivity is very potential to increase every year. However, the level of palm oil productivity is lower than its potential. Pests and diseases are the main factors that can reduce production levels by up to 40%. The existence of pests in plants can be caused by various factors, so the anticipation in controlling pest attacks should be prepared as early as possible. Caterpillars are the main pests in oil palm. The nettle caterpillars are leaf eaters that can significantly decrease palm productivity. We construct a deterministic model that describes the life cycle of the caterpillar and its mitigation by using a caterpillar predator. The equilibrium points of the model are analyzed. The numerical simulations are constructed to give a representation how the predator as the natural enemies affects the nettle caterpillar life cycle.

Atomic scale study of the life cycle of a dislocation in graphene from birth to annihilation

NASA Astrophysics Data System (ADS)

Lehtinen, O.; Kurasch, S.; Krasheninnikov, A. V.; Kaiser, U.

2013-06-01

Dislocations, one of the key entities in materials science, govern the properties of any crystalline material. Thus, understanding their life cycle, from creation to annihilation via motion and interaction with other dislocations, point defects and surfaces, is of fundamental importance. Unfortunately, atomic-scale investigations of dislocation evolution in a bulk object are well beyond the spatial and temporal resolution limits of current characterization techniques. Here we overcome the experimental limits by investigating the two-dimensional graphene in an aberration-corrected transmission electron microscope, exploiting the impinging energetic electrons both to image and stimulate atomic-scale morphological changes in the material. The resulting transformations are followed in situ, atom-by-atom, showing the full life cycle of a dislocation from birth to annihilation. Our experiments, combined with atomistic simulations, reveal the evolution of dislocations in two-dimensional systems to be governed by markedly long-ranging out-of-plane buckling.

Recurrent sublethal warming reduces embryonic survival, inhibits juvenile growth, and alters species distribution projections under climate change.

PubMed

Carlo, Michael A; Riddell, Eric A; Levy, Ofir; Sears, Michael W

2018-01-01

The capacity to tolerate climate change often varies across ontogeny in organisms with complex life cycles. Recently developed species distribution models incorporate traits across life stages; however, these life-cycle models primarily evaluate effects of lethal change. Here, we examine impacts of recurrent sublethal warming on development and survival in ecological projections of climate change. We reared lizard embryos in the laboratory under temperature cycles that simulated contemporary conditions and warming scenarios. We also artificially warmed natural nests to mimic laboratory treatments. In both cases, recurrent sublethal warming decreased embryonic survival and hatchling sizes. Incorporating survivorship results into a mechanistic species distribution model reduced annual survival by up to 24% compared to models that did not incorporate sublethal warming. Contrary to models without sublethal effects, our model suggests that modest increases in developmental temperatures influence species ranges due to effects on survivorship. © 2017 John Wiley & Sons Ltd/CNRS.

Computational Infrastructure for Engine Structural Performance Simulation

NASA Technical Reports Server (NTRS)

Chamis, Christos C.

1997-01-01

Select computer codes developed over the years to simulate specific aspects of engine structures are described. These codes include blade impact integrated multidisciplinary analysis and optimization, progressive structural fracture, quantification of uncertainties for structural reliability and risk, benefits estimation of new technology insertion and hierarchical simulation of engine structures made from metal matrix and ceramic matrix composites. Collectively these codes constitute a unique infrastructure readiness to credibly evaluate new and future engine structural concepts throughout the development cycle from initial concept, to design and fabrication, to service performance and maintenance and repairs, and to retirement for cause and even to possible recycling. Stated differently, they provide 'virtual' concurrent engineering for engine structures total-life-cycle-cost.

Development of single-cell protectors for sealed silver-zinc cells

NASA Technical Reports Server (NTRS)

Lear, J. W.; Donovan, R. L.; Imamura, M. S.

1978-01-01

Three design approaches to cell-level protection were developed, fabricated, and tested. These systems are referred to as the single-cell protector (SCP), multiplexed-cell protector(MCP). To evaluate the systems 18-cell battery packs without cell level control were subjected to cycle life test. A total of five batteries were subjected to simulate synchronous orbit cycling at 40% depth of discharge at 22C. Batteries without cell-level protection failed between 345 and 255 cycles. Cell failure in the cell level protected batteries occurred between 412 and 540. It was determined that the cell-level monitoring and protection is necessary to attain the long cycle life of a AgZn battery. The best method of providing control and protection of the AgZn cells depends on the specific application and capability of the user.

On the experimental approaches for the assessment of the release of engineered nanomaterials from nanocomposites by physical degradation processes

NASA Astrophysics Data System (ADS)

Blázquez, M.; Egizabal, A.; Unzueta, I.

2014-08-01

The LIFE+ Project SIRENA, Simulation of the release of nanomaterials from consumer products for environmental exposure assessment, (LIFE11 ENV/ES/596) has set up a Technological Surveillance System (TSS) to trace technical references at worldwide level related to nanocomposites and the release from nanocomposites. So far a total of seventy three items of different nature (from peer reviewed articles to presentations and contributions to congresses) have been selected and classified as "nanomaterials release simulation technologies". In present document, different approaches for the simulation of different life cycle stages through the physical degradation of polymer nanocomposites at laboratory scale are assessed. In absence of a reference methodology, the comparison of the different protocols used still remains a challenge.

A quantitative evaluation of the iron-sulfur world and its relevance to life's origins.

PubMed

Ross, David S

2008-04-01

The significance of Wächtershäuser's iron-sulfur world to the origin of life and the limits to its notional autocatalytic cycles are examined in kinetic simulations of the chain polymerization sequence: primitive materials-->amino acids-->oligomers. The simulations were run for the formation of all oligomers up to the 20-mer over a 1 Gy interval from the end of the period of heavy bombardment, during which period life emerged. Upper-limit rate constant estimates developed from the studies of Huber and Wächtershäuser were employed. The simulations showed that oligomer production consistent with life's start within that interval emerges only with an autocatalyst exhibiting a catalytic proficiency comparable to that of contemporary enzymes. The simulations, moreover, ignored likely thermodynamic and statistical burdens which, if included, would have led to the need for catalytic capacities well in excess of those in present-day enzymes. Prebiotic oligomers with such levels of activity are clearly not likely, and it is apparent that the iron-sulfur scheme could not have played a role in life's beginnings.

A quantitative evaluation of the iron-sulfur world and its relevance to life's origins

USGS Publications Warehouse

Ross, D.S.

2008-01-01

The significance of Wa??chtersha??user's iron-sulfur world to the origin of life and the limits to its notional autocatalytic cycles are examined in kinetic simulations of the chain polymerization sequence primitive materials ??? amino acids ??? oligomers The simulations were run for the formation of all oligomers up to the 20-mer over a 1 Gy interval from the end of the period of heavy bombardment, during which period life emerged. Upper-limit rate constant estimates developed from the studies of Huber and Wa??chtersha?? user were employed. The simulations showed that oligomer production consistent with life's start within that interval emerges only with an autocatalyst exhibiting a catalytic proficiency comparable to that of contemporary enzymes. The simulations, moreover, ignored likely thermodynamic and statistical burdens which, if included, would have led to the need for catalytic capacities well in excess of those in present-day enzymes. Prebiotic oligomers with such levels of activity are clearly not likely, and it is apparent that the iron-sulfur scheme could not have played a role in life's beginnings. ?? 2008 Mary Ann Liebert, Inc.

A lithium–oxygen battery with a long cycle life in an air-like atmosphere

NASA Astrophysics Data System (ADS)

Asadi, Mohammad; Sayahpour, Baharak; Abbasi, Pedram; Ngo, Anh T.; Karis, Klas; Jokisaari, Jacob R.; Liu, Cong; Narayanan, Badri; Gerard, Marc; Yasaei, Poya; Hu, Xuan; Mukherjee, Arijita; Lau, Kah Chun; Assary, Rajeev S.; Khalili-Araghi, Fatemeh; Klie, Robert F.; Curtiss, Larry A.; Salehi-Khojin, Amin

2018-03-01

Lithium–air batteries are considered to be a potential alternative to lithium-ion batteries for transportation applications, owing to their high theoretical specific energy. So far, however, such systems have been largely restricted to pure oxygen environments (lithium–oxygen batteries) and have a limited cycle life owing to side reactions involving the cathode, anode and electrolyte. In the presence of nitrogen, carbon dioxide and water vapour, these side reactions can become even more complex. Moreover, because of the need to store oxygen, the volumetric energy densities of lithium–oxygen systems may be too small for practical applications. Here we report a system comprising a lithium carbonate-based protected anode, a molybdenum disulfide cathode and an ionic liquid/dimethyl sulfoxide electrolyte that operates as a lithium–air battery in a simulated air atmosphere with a long cycle life of up to 700 cycles. We perform computational studies to provide insight into the operation of the system in this environment. This demonstration of a lithium–oxygen battery with a long cycle life in an air-like atmosphere is an important step towards the development of this field beyond lithium-ion technology, with a possibility to obtain much higher specific energy densities than for conventional lithium-ion batteries.

A lithium-oxygen battery with a long cycle life in an air-like atmosphere.

PubMed

Asadi, Mohammad; Sayahpour, Baharak; Abbasi, Pedram; Ngo, Anh T; Karis, Klas; Jokisaari, Jacob R; Liu, Cong; Narayanan, Badri; Gerard, Marc; Yasaei, Poya; Hu, Xuan; Mukherjee, Arijita; Lau, Kah Chun; Assary, Rajeev S; Khalili-Araghi, Fatemeh; Klie, Robert F; Curtiss, Larry A; Salehi-Khojin, Amin

2018-03-21

Lithium-air batteries are considered to be a potential alternative to lithium-ion batteries for transportation applications, owing to their high theoretical specific energy. So far, however, such systems have been largely restricted to pure oxygen environments (lithium-oxygen batteries) and have a limited cycle life owing to side reactions involving the cathode, anode and electrolyte. In the presence of nitrogen, carbon dioxide and water vapour, these side reactions can become even more complex. Moreover, because of the need to store oxygen, the volumetric energy densities of lithium-oxygen systems may be too small for practical applications. Here we report a system comprising a lithium carbonate-based protected anode, a molybdenum disulfide cathode and an ionic liquid/dimethyl sulfoxide electrolyte that operates as a lithium-air battery in a simulated air atmosphere with a long cycle life of up to 700 cycles. We perform computational studies to provide insight into the operation of the system in this environment. This demonstration of a lithium-oxygen battery with a long cycle life in an air-like atmosphere is an important step towards the development of this field beyond lithium-ion technology, with a possibility to obtain much higher specific energy densities than for conventional lithium-ion batteries.

EOS--AM1 Nickel Hydrogen Cell Interim Life Test Report

NASA Technical Reports Server (NTRS)

Bennett, C. W.; Keys, D. J.; Rao, G. M.; Wannemacher, H. E.; Vaidyanathan H.

1999-01-01

This paper reports the interim results of the Earth Observing System AM-1 project (EOS-AM-1) nickel hydrogen cell life test being conducted under contract to National Aeronautics and Space Administration (NASA) Goddard Space Flight Center (GSFC) at the Lockheed Martin Missiles and Space (LMMS) facility in East Windsor, NJ; and at COMSAT Labs., Clarksburg, MD. The purpose of the tests is to verify that the EOS-AM-1 cell design can meet five years of real-time Low Earth Orbit (LEO) cycling. The tests include both real-time LEO and accelerated stress tests. At LMMS, the first real-time LEO simulated 99 minute orbital cycle started on February 7, 1994 and the test has been running continuously since that time, with 18202 LEO cycles completed as of September 1, 1997. Each cycle consists of a 64 minute charge (VT at 1.507 volts per cell. 1.06 C/D ratio, followed by 0.6 ampere trickle charge) and a 35 minute constant power discharge at 177 watts (22.5% DOD). At COMSAT, the accelerated stress test consists of 90 minute orbital cycles at 60% DOD with a 30 minute discharge at 60 amperes and a 60 minute charge at 40 amperes (VT at 1.54 volts per cell to 1.09 C/D ratio, followed by 0.6 ampere trickle charge). The real-time LEO life test battery consists of seven, 50AH (nameplate rating) Eagle-Picher, Inc. (EPI) Mantech cells manufactured into three. 3-cell pack assemblies (there are two place holder cells that are not part of the life test electrical circuit). The test pack is configured to simulate the conductive thermal design of the spacecraft battery, including: conductive aluminum sleeves, 3-cell pack aluminum baseplate, and honeycomb panel all mounted to a liquid (-5 C) cold plate. The entire assembly is located in a thermal chamber operatina at +30 C. The accelerated stress test unit consists of five cells mounted in machined aluminum test sleeves and is operating at +10 C. The real-time LEO life test battery has met all performance requirements throuch the first 18,202 cycles, including: end of chargee and discharge cell voltages and voltace -radients; end of charge and discharge cell pressures; within cell and between cell temperature gradients; discharge capacity; current and power levels; and all charge parameters. The accelerated stress test battery has completed 11,998 cycles when the test was terminated. The stress test unit met all test parameters. This paper reports battery performances as a function of cycle life for both the real time LEO and the accelerated life test regimes.

EOS-AM1 Nickel Hydrogen Cell Interim Life Test Report

NASA Technical Reports Server (NTRS)

Bennett, Charles W.; Keys, D. J.; Rao, G. M.; Wannemacher, H. E.; Vaidyanathan, Hari

1998-01-01

This paper reports the interim results Earth Observing System AM-1 project (EOS-AM-1) nickel hydrogen cell life test being conducted under contract to National Aeronautics and Space Administration (NASA) Goddard Space Flight Center (GSFC) at the Lockheed Martin Missiles and Space (LMMS) facility in East Windsor, NJ; and at COMSAT Labs., Clarksburg, MD. The purpose of the tests is to verify that the EOS-AM-1 cell design can meet five years of real-time Low Earth Orbit (LEO) cycling. The tests include both real-time LEO and accelerated stress tests. At LMMS, the first real-time LEO simulated 99 minute orbital cycle started on February 7, 1994 and the test has been running continuously since that time, with 18202 LEO cycles completed as of September 1, 1997. Each cycle consists of a 64-minute charge (VT at 1,507 volts per cell, 1.06 C/D ratio, followed by 0.6 ampere trickle charge) and a 35 minute constant power discharge at 177 watts (22.5 percent DOD). At COMSAT, the accelerated stress test consists of 90 minute orbital cycles at 60 percent DOD with a 30 minute discharge at 60 amperes and a 60 minute charge at 40 amperes (VT at 1.54 volts per cell to 1.90 C/D ratio, followed by 0.6 ampere trickle charge). The real-time LEO life test battery consists of seven, 50AH (nameplate rating) Eagle-Picher, Inc. (EPI) Mantech cells manufactured into three, 3-cell pack assemblies (there are two place holder cells that are not part of the life test electrical circuit). The test pack is configured to simulate the conductive thermal design of the spacecraft battery, including: conductive aluminum sleeves, 3-cell pack aluminum baseplate, and honeycomb panel all mounted to a liquid (minus 5 deg) cold plate. The entire assembly is located in a thermal chamber operating at plus 3 deg. The accelerated stress test unit consists of five cells mounted in machined aluminum test sleeves and is operating at plus 10 deg. The real-time LEO life test battery has met all performance requirements through the first 18,202 cycles, including: end of charge and discharge cell voltages and voltage gradients; end of charge and discharge cells pressures; within cell and between cell temperature gradients dischare capacity; current and power levels; and all charge parameters. The accelerated stress test battery has completed 11998 cycles when the test was terminated. The stress test unit met all test parameters. This paper reports battery performances as a function of cycle life for both the real-time LEO and the accelerated life test regimes.

Coupling Computer-Aided Process Simulation and ...

EPA Pesticide Factsheets

A methodology is described for developing a gate-to-gate life cycle inventory (LCI) of a chemical manufacturing process to support the application of life cycle assessment in the design and regulation of sustainable chemicals. The inventories were derived by first applying process design and simulation of develop a process flow diagram describing the energy and basic material flows of the system. Additional techniques developed by the U.S. Environmental Protection Agency for estimating uncontrolled emissions from chemical processing equipment were then applied to obtain a detailed emission profile for the process. Finally, land use for the process was estimated using a simple sizing model. The methodology was applied to a case study of acetic acid production based on the Cativa tm process. The results reveal improvements in the qualitative LCI for acetic acid production compared to commonly used databases and top-down methodologies. The modeling techniques improve the quantitative LCI results for inputs and uncontrolled emissions. With provisions for applying appropriate emission controls, the proposed method can provide an estimate of the LCI that can be used for subsequent life cycle assessments. As part of its mission, the Agency is tasked with overseeing the use of chemicals in commerce. This can include consideration of a chemical's potential impact on health and safety, resource conservation, clean air and climate change, clean water, and sustainable

Propulsion system mathematical model for a lift/cruise fan V/STOL aircraft

NASA Technical Reports Server (NTRS)

Cole, G. L.; Sellers, J. F.; Tinling, B. E.

1980-01-01

A propulsion system mathematical model is documented that allows calculation of internal engine parameters during transient operation. A non-realtime digital computer simulation of the model is presented. It is used to investigate thrust response and modulation requirements as well as the impact of duty cycle on engine life and design criteria. Comparison of simulation results with steady-state cycle deck calculations showed good agreement. The model was developed for a specific 3-fan subsonic V/STOL aircraft application, but it can be adapted for use with any similar lift/cruise V/STOL configuration.

Life-Cycle Cost/Benefit Assessment of Expedite Departure Path (EDP)

NASA Technical Reports Server (NTRS)

Wang, Jianzhong Jay; Chang, Paul; Datta, Koushik

2005-01-01

This report presents a life-cycle cost/benefit assessment (LCCBA) of Expedite Departure Path (EDP), an air traffic control Decision Support Tool (DST) currently under development at NASA. This assessment is an update of a previous study performed by bd Systems, Inc. (bd) during FY01, with the following revisions: The life-cycle cost assessment methodology developed by bd for the previous study was refined and calibrated using Free Flight Phase 1 (FFP1) cost information for Traffic Management Advisor (TMA, or TMA-SC in the FAA's terminology). Adjustments were also made to the site selection and deployment scheduling methodology to include airspace complexity as a factor. This technique was also applied to the benefit extrapolation methodology to better estimate potential benefits for other years, and at other sites. This study employed a new benefit estimating methodology because bd s previous single year potential benefit assessment of EDP used unrealistic assumptions that resulted in optimistic estimates. This methodology uses an air traffic simulation approach to reasonably predict the impacts from the implementation of EDP. The results of the costs and benefits analyses were then integrated into a life-cycle cost/benefit assessment.

Near Zero Energy House (NZEH) Design Optimization to Improve Life Cycle Cost Performance Using Genetic Algorithm

NASA Astrophysics Data System (ADS)

Latief, Y.; Berawi, M. A.; Koesalamwardi, A. B.; Supriadi, L. S. R.

2018-03-01

Near Zero Energy House (NZEH) is a housing building that provides energy efficiency by using renewable energy technologies and passive house design. Currently, the costs for NZEH are quite expensive due to the high costs of the equipment and materials for solar panel, insulation, fenestration and other renewable energy technology. Therefore, a study to obtain the optimum design of a NZEH is necessary. The aim of the optimum design is achieving an economical life cycle cost performance of the NZEH. One of the optimization methods that could be utilized is Genetic Algorithm. It provides the method to obtain the optimum design based on the combinations of NZEH variable designs. This paper discusses the study to identify the optimum design of a NZEH that provides an optimum life cycle cost performance using Genetic Algorithm. In this study, an experiment through extensive design simulations of a one-level house model was conducted. As a result, the study provide the optimum design from combinations of NZEH variable designs, which are building orientation, window to wall ratio, and glazing types that would maximize the energy generated by photovoltaic panel. Hence, the design would support an optimum life cycle cost performance of the house.

Life cycle responses to health insurance status.

PubMed

Pelgrin, Florian; St-Amour, Pascal

2016-09-01

This paper studies the lifetime effects of exogenous changes in health insurance coverage (e.g. Medicare, PPACA, termination of employer-provided plans) on the dynamic optimal allocation (consumption, leisure, health expenditures), status (health and wealth), and welfare. We solve, simulate, and structurally estimate a parsimonious life cycle model with endogenous exposure to morbidity and mortality risks, and exogenous health insurance. By varying coverage, we identify the marginal effects of insurance when young and/or when old on allocations, statuses, and welfare. Our results highlight positive effects of insurance on health, wealth and welfare, as well as mid-life substitution away from healthy leisure in favor of more health expenses, caused by peaking wages, and accelerating health issues. Copyright © 2016 Elsevier B.V. All rights reserved.

Optimal design of green and grey stormwater infrastructure for small urban catchment based on life-cycle cost-effectiveness analysis

NASA Astrophysics Data System (ADS)

Yang, Y.; Chui, T. F. M.

2016-12-01

Green infrastructure (GI) is identified as sustainable and environmentally friendly alternatives to the conventional grey stormwater infrastructure. Commonly used GI (e.g. green roof, bioretention, porous pavement) can provide multifunctional benefits, e.g. mitigation of urban heat island effects, improvements in air quality. Therefore, to optimize the design of GI and grey drainage infrastructure, it is essential to account for their benefits together with the costs. In this study, a comprehensive simulation-optimization modelling framework that considers the economic and hydro-environmental aspects of GI and grey infrastructure for small urban catchment applications is developed. Several modelling tools (i.e., EPA SWMM model, the WERF BMP and LID Whole Life Cycle Cost Modelling Tools) and optimization solvers are coupled together to assess the life-cycle cost-effectiveness of GI and grey infrastructure, and to further develop optimal stormwater drainage solutions. A typical residential lot in New York City is examined as a case study. The life-cycle cost-effectiveness of various GI and grey infrastructure are first examined at different investment levels. The results together with the catchment parameters are then provided to the optimization solvers, to derive the optimal investment and contributing area of each type of the stormwater controls. The relationship between the investment and optimized environmental benefit is found to be nonlinear. The optimized drainage solutions demonstrate that grey infrastructure is preferred at low total investments while more GI should be adopted at high investments. The sensitivity of the optimized solutions to the prices the stormwater controls is evaluated and is found to be highly associated with their utilizations in the base optimization case. The overall simulation-optimization framework can be easily applied to other sites world-wide, and to be further developed into powerful decision support systems.

The Analysis, Numerical Simulation, and Diagnosis of Extratropical Weather Systems

DTIC Science & Technology

1999-09-30

The Analysis, Numerical Simulation, and Diagnosis of Extratropical Weather Systems Dr. Melvyn A. Shapiro NOAA/Environmental Technology Laboratory...formulation, and numerical prediction of the life cycles of synoptic-scale and mesoscale extratropical weather systems, including the influence of planetary...scale inter-annual and intra-seasonal variability on their evolution. These weather systems include: extratropical oceanic and land-falling cyclones

Performance characterization tests of three 0.44-N (0.1 lbf) hydrazine catalytic thrusters

NASA Technical Reports Server (NTRS)

Moynihan, P. I.; Bjorklund, R. A.

1973-01-01

The 0.44-N (0.1-lbf) class of hydrazine catalytic thruster has been evaluated to assess its capability for spacecraft limit-cycle attitude control with thruster pulse durations on the order of 10 milliseconds. Dynamic-environment and limit-cycle simulation tests were performed on three commercially available thruster/valve assemblies, purchased from three different manufacturers. The results indicate that this class of thruster can sustain a launch environment and, when properly temperature-conditioned, can perform limit-cycle operations over the anticipated life span of a multi-year mission. The minimum operating temperature for very short pulse durations was determined for each thruster. Pulsing life tests were then conducted on each thruster under a thermally controlled condition which maintained the catalyst bed at both a nominal 93 C (200 F) and 205 C (400 F). These were the temperatures believed to be slightly below and very near the minimum recommended operating temperature, respectively. The ensuing life tests ranged from 100,000 to 250,000 pulses at these temperatures, as would be required for spacecraft limit-cycle attitude control applications.

Evaluation Of Model Based Systems Engineering Processes For Integration Into Rapid Acquisition Programs

DTIC Science & Technology

2016-09-01

Failure MTBCF Mean Time Between Critical Failure MIRV Multiple Independently-targetable Reentry Vehicle MK6LE MK6 Guidance System Life Extension...programs were the MK54 Lightweight Torpedo program, a Raytheon Radar program, and the Life Extension of the MK6 Guidance System (MK6LE) of the...activities throughout the later life -cycle phases. MBSE allowed the programs to manage the evolution of simulation capabilities, as well as to assess the

The fatigue life prediction of aluminium alloy using genetic algorithm and neural network

NASA Astrophysics Data System (ADS)

Susmikanti, Mike

2013-09-01

The behavior of the fatigue life of the industrial materials is very important. In many cases, the material with experiencing fatigue life cannot be avoided, however, there are many ways to control their behavior. Many investigations of the fatigue life phenomena of alloys have been done, but it is high cost and times consuming computation. This paper report the modeling and simulation approaches to predict the fatigue life behavior of Aluminum Alloys and resolves some problems of computation. First, the simulation using genetic algorithm was utilized to optimize the load to obtain the stress values. These results can be used to provide N-cycle fatigue life of the material. Furthermore, the experimental data was applied as input data in the neural network learning, while the samples data were applied for testing of the training data. Finally, the multilayer perceptron algorithm is applied to predict whether the given data sets in accordance with the fatigue life of the alloy. To achieve rapid convergence, the Levenberg-Marquardt algorithm was also employed. The simulations results shows that the fatigue behaviors of aluminum under pressure can be predicted. In addition, implementation of neural networks successfully identified a model for material fatigue life.

Emergent multicellular life cycles in filamentous bacteria owing to density-dependent population dynamics.

PubMed

Rossetti, Valentina; Filippini, Manuela; Svercel, Miroslav; Barbour, A D; Bagheri, Homayoun C

2011-12-07

Filamentous bacteria are the oldest and simplest known multicellular life forms. By using computer simulations and experiments that address cell division in a filamentous context, we investigate some of the ecological factors that can lead to the emergence of a multicellular life cycle in filamentous life forms. The model predicts that if cell division and death rates are dependent on the density of cells in a population, a predictable cycle between short and long filament lengths is produced. During exponential growth, there will be a predominance of multicellular filaments, while at carrying capacity, the population converges to a predominance of short filaments and single cells. Model predictions are experimentally tested and confirmed in cultures of heterotrophic and phototrophic bacterial species. Furthermore, by developing a formulation of generation time in bacterial populations, it is shown that changes in generation time can alter length distributions. The theory predicts that given the same population growth curve and fitness, species with longer generation times have longer filaments during comparable population growth phases. Characterization of the environmental dependence of morphological properties such as length, and the number of cells per filament, helps in understanding the pre-existing conditions for the evolution of developmental cycles in simple multicellular organisms. Moreover, the theoretical prediction that strains with the same fitness can exhibit different lengths at comparable growth phases has important implications. It demonstrates that differences in fitness attributed to morphology are not the sole explanation for the evolution of life cycles dominated by multicellularity.

Development of service-oriented products based on the inverse manufacturing concept.

PubMed

Fujimoto, Jun; Umeda, Yasushi; Tamura, Tetsuya; Tomiyama, Tetsuo; Kimura, Fumihiko

2003-12-01

To achieve sustainability, resource consumption and waste generation must be drastically decreased. For societal acceptance, preservation of both quality of life and corporate profits are essential. One promising approach is to shift the source of value from the amount of product sold to the quality of services the product provides. This paper describes the need for redesigning recycling systems from a manufacturing perspective and then discusses the possibility of this "servicification" of products, describing our experience with prototype development. We discuss development of product prototypes and their business, using consumer facsimile machines as an example of "service-oriented products". Traditional thought presumes that only products comprising new materials and components are valuable. Consideration of a service-oriented product can serve as a stimulus to revise this mode of thought and to control delivery and quality of disposed products. This paper also provides a life cycle simulation of the developed service-oriented business. Simulation results indicate that service-oriented business can potentially reduce environmental impact while extending business opportunities from the viewpoint of whole product life cycles.

Accelerated and real-time geosynchronous life cycling test performance of nickel-hydrogen batteries

NASA Technical Reports Server (NTRS)

Green, R. S.

1985-01-01

RCA Astro-Electronics currently has four nickel-hydrogen storage battery modules (11 cells each) on test in simulated geosynchronous life cycle regimes. These battery modules are of identical design to those used on the GSTAR (GTE Satellite Corp.) and Spacenet (GTE Spacenet Corp.) communications satellites. The batteries are being tested using an automated test station equipped with computer-controlled environmental chambers and recording equipment. The two battery types, 30 ampere-hours and 40 ampere-hours (GSTAR and Spacenet, respectively), are being electrically cycled using identical 44-day eclipse sequences at 5 C and vary with respect to depth of discharge, recharge ratio, duration of accumulated suntime, and the use of a reconditioning sequence. The test parameters are outlined and the preliminary test data and results are presented.

National Cycle Program (NCP) Common Analysis Tool for Aeropropulsion

NASA Technical Reports Server (NTRS)

Follen, G.; Naiman, C.; Evans, A.

1999-01-01

Through the NASA/Industry Cooperative Effort (NICE) agreement, NASA Lewis and industry partners are developing a new engine simulation, called the National Cycle Program (NCP), which is the initial framework of NPSS. NCP is the first phase toward achieving the goal of NPSS. This new software supports the aerothermodynamic system simulation process for the full life cycle of an engine. The National Cycle Program (NCP) was written following the Object Oriented Paradigm (C++, CORBA). The software development process used was also based on the Object Oriented paradigm. Software reviews, configuration management, test plans, requirements, design were all apart of the process used in developing NCP. Due to the many contributors to NCP, the stated software process was mandatory for building a common tool intended for use by so many organizations. The U.S. aircraft and airframe companies recognize NCP as the future industry standard for propulsion system modeling.

Development and validation of cryogenic foam insulation for LH2 subsonic transports

NASA Technical Reports Server (NTRS)

Anthony, F. M.; Colt, J. Z.; Helenbrook, R. G.

1981-01-01

Fourteen foam insulation specimens were tested. Some were plain foam while others contained flame retardants, chopped fiberglass reinforcement and/or vapor barriers. The thermal performance of the insulation was determined by measuring the rate at which LH2 boiled from an aluminum tank insulated with the test material. The test specimens were approximately 50 mm (2 in.) thick. They were structurally scaled so that the test cycle would duplicate the maximum thermal stresses predicted for the thicker insulation of an aircraft liquid hydrogen fuel tank during a typical subsonic flight. The simulated flight cycle of approximately 10 minutes duration heated the other insulation surface to 316 K (110 F) and cooled it to 226 K (20 F) while the inner insulation surface remained at liquid hydrogen temperature of 20 K (-423 F). Two urethane foam insulations exceeded the initial life goal of 2400 simulated flight cycles and sustained 4400 cycles with only minor damage. The addition of fiberglass reinforcement of flame retardant materials to an insulation degraded thermal performance and/or the life of the foam material. Installation of vapor barriers enhanced the structural integrity of the material but did not improve thermal performance. All of the foams tested were available materials; none were developed specifically for LH2 service.

EOS-AM1 Nickel Hydrogen Cell

NASA Technical Reports Server (NTRS)

Bennett, Charles W.; Keys, Denney J.; Rao, Gopalakrishna M.; Wannemacher, Hari E.; Vaidyanathan, Harry

1997-01-01

This paper reports the interim results of the Earth Observing System AM-1 project (EOS-AM-1) nickel hydrogen cell life test being conducted under contract to National Aeronautics and Space Administration (NASA) Goddard Space Flight Center (GSFC) at the Lockheed Martin Missile and Space (LMMS) facility in East Windsor, NJ; and at COMSAT Labs., Clarksburg, MD. The purpose of die tests is to verify that the EOS-AM-1 cell design can meet five years of real-time Low Earth Orbit (LEO) cycling. The tests include both real-time LEO and accelerated stress tests. At LMMS, the first real-time LEO simulated 99 minute orbital cycle started on February 7, 1994 and the test has been running continuously since that time, with 18,202 LEO cycles completed as of September 1, 1997. Each cycle consists of a 64 minute charge (VT at 1.507 volts per cell, 1.06 C/D ratio, followed by 0.6 ampere trickle charge) and a 35 minute constant power discharge at 177 watts (22.5% DOD). At COMSAT, the accelerated stress test consists of 90 minute orbital cycles at 60% DOD with a 30 minute discharge at 60 amperes and a 60 minute charge at 40 amperes (VT at 1.54 volts per cell to 1.09 C/D ratio, followed by 0.6 ampere trickle charge). The real-time LEO life test battery consists of seven, 50AH (nameplate rating) Eagle-Picher, Inc. (EPI) Mantech cells manufactured into three, 3-cell pack assemblies (there are two place holder cells that are not part of the life test electrical circuit). The test pack is configured to simulate the conductive thermal design of the spacecraft battery, including: conductive aluminum sleeves, 3-cell pack aluminum baseplate, and honeycomb panel all mounted to a liquid (-5 C) cold plate. The entire assembly is located in a thermal chamber operating at +30 C. The accelerated stress test unit consists of five cells mounted in machined aluminum test sleeves and is operating at +10 C. The real-time LEO life test battery has met all performance requirements through the first 18,202 cycles, including: end of charge mid discharge cell voltages and voltage gradients; end of charge and discharge cell pressures; within cell and between cell temperature gradients; discharge capacity; current and power levels; and all charge parameters. The accelerated stress test battery has completed 11,998 cycles when the test was terminated. The stress test unit met all test parameters. This paper reports battery perfortnances as a funcfion of cycle life for both the real-time LEO and the accelerated life test regimes.

Evolutionary behaviour, trade-offs and cyclic and chaotic population dynamics.

PubMed

Hoyle, Andy; Bowers, Roger G; White, Andy

2011-05-01

Many studies of the evolution of life-history traits assume that the underlying population dynamical attractor is stable point equilibrium. However, evolutionary outcomes can change significantly in different circumstances. We present an analysis based on adaptive dynamics of a discrete-time demographic model involving a trade-off whose shape is also an important determinant of evolutionary behaviour. We derive an explicit expression for the fitness in the cyclic region and consequently present an adaptive dynamic analysis which is algebraic. We do this fully in the region of 2-cycles and (using a symbolic package) almost fully for 4-cycles. Simulations illustrate and verify our results. With equilibrium population dynamics, trade-offs with accelerating costs produce a continuously stable strategy (CSS) whereas trade-offs with decelerating costs produce a non-ES repellor. The transition to 2-cycles produces a discontinuous change: the appearance of an intermediate region in which branching points occur. The size of this region decreases as we move through the region of 2-cycles. There is a further discontinuous fall in the size of the branching region during the transition to 4-cycles. We extend our results numerically and with simulations to higher-period cycles and chaos. Simulations show that chaotic population dynamics can evolve from equilibrium and vice-versa.

OAO-3 end of mission power subsystem evaluation

NASA Technical Reports Server (NTRS)

Tasevoli, M.

1982-01-01

End of mission tests were performed on the OAO-3 power subsystem in three component areas: solar array, nickel-cadmium batteries and the On-Board Processor (OBP) power boost operation. Solar array evaluation consisted of analyzing array performance characteristics and comparing them to earlier flight data. Measured solar array degradation of 14.1 to 17.7% after 8 1/3 years is in good agreement with theortical radiation damage losses. Battery discharge characteristics were compared to results of laboratory life cycle tests performed on similar cells. Comparison of cell voltage profils reveals close correlation and confirms the validity of real time life cycle simulation. The successful operation of the system in the OBP/power boost regulation mode demonstrates the excellent life, reliability and greater system utilization of power subsystems using maximum power trackers.

DOE Office of Scientific and Technical Information (OSTI.GOV)

None

An OpenStudio Measure is a script that can manipulate an OpenStudio model and associated data to apply energy conservation measures (ECMs), run supplemental simulations, or visualize simulation results. The OpenStudio software development kit (SDK) and accessibility of the Ruby scripting language makes measure authorship accessible to both software developers and energy modelers. This paper discusses the life cycle of an OpenStudio Measure from development, testing, and distribution, to application.

Isothermal and thermal-mechanical fatigue of VVER-440 reactor pressure vessel steels

NASA Astrophysics Data System (ADS)

Fekete, Balazs; Trampus, Peter

2015-09-01

The fatigue life of the structural materials 15Ch2MFA (CrMoV-alloyed ferritic steel) and 08Ch18N10T (CrNi-alloyed austenitic steel) of VVER-440 reactor pressure vessel under completely reserved total strain controlled low cycle fatigue tests were investigated. An advanced test facility was developed for GLEEBLE-3800 physical simulator which was able to perform thermomechanical fatigue experiments under in-service conditions of VVER nuclear reactors. The low cycle fatigue results were evaluated with the plastic strain based Coffin-Manson law, and plastic strain energy based model as well. It was shown that both methods are able to predict the fatigue life of reactor pressure vessel steels accurately. Interrupted fatigue tests were also carried out to investigate the kinetic of the fatigue evolution of the materials. On these samples microstructural evaluation by TEM was performed. The investigated low cycle fatigue behavior can provide reference for remaining life assessment and lifetime extension analysis.

Initial studies of middle and upper tropospheric stratiform clouds

NASA Technical Reports Server (NTRS)

Cox, S. K.

1982-01-01

The spatial and temporal occurrence of cloud layers, the development of a physical-numerical model to simulate the life cycles of tropospheric cloud layers, and the design of an observational program to study the properties of these layers are described.

Biodiesel Research : Alternative Fuels & Life-Cycle Engineering Program : November 29, 2006 to November 28, 2011

DOT National Transportation Integrated Search

2011-12-20

The primary objective of this project is to develop multiple simulation Testbeds/transportation models to evaluate the impacts of DMA connected vehicle applications and the active and dynamic transportation management (ATDM) strategies. The outputs (...

REGULATION OF GEOGRAPHIC VARIABILITY IN HAPLOID:DIPLOD RATIOS OF BIPHASIC SEAWEED LIFE CYCLES(1).

PubMed

da Silva Vieira, Vasco Manuel Nobre de Carvalho; Santos, Rui Orlando Pimenta

2012-08-01

The relative abundance of haploid and diploid individuals (H:D) in isomorphic marine algal biphasic cycles varies spatially, but only if vital rates of haploid and diploid phases vary differently with environmental conditions (i.e. conditional differentiation between phases). Vital rates of isomorphic phases in particular environments may be determined by subtle morphological or physiological differences. Herein, we test numerically how geographic variability in H:D is regulated by conditional differentiation between isomorphic life phases and the type of life strategy of populations (i.e. life cycles dominated by reproduction, survival or growth). Simulation conditions were selected using available data on H:D spatial variability in seaweeds. Conditional differentiation between ploidy phases had a small effect on the H:D variability for species with life strategies that invest either in fertility or in growth. Conversely, species with life strategies that invest mainly in survival, exhibited high variability in H:D through a conditional differentiation in stasis (the probability of staying in the same size class), breakage (the probability of changing to a smaller size class) or growth (the probability of changing to a bigger size class). These results were consistent with observed geographic variability in H:D of natural marine algae populations. © 2012 Phycological Society of America.

The tropopause inversion layer in baroclinic life cycles over the North Atlantic: a pre-WISE case study and climatology

NASA Astrophysics Data System (ADS)

Kaluza, Thorsten; Hoor, Peter; Kunkel, Daniel

2017-04-01

Studies of baroclinic life cycles recently revelead that the tropopause inversion layer (TIL) in the extratropics is significantly strengthened by diabatic processes related to moist tropospheric dynamics as well as by breaking of the baroclinic wave itself. However, these findings summarize the results from idealized model simulations and the contribution from processes related to baroclinic life cycles relative to other processes enhancing the lower stratospheric static stability (stratospheric dynamics, seasonal variation of radiative feedbacks) to the observed TIL at midlatitudes has yet to be assessed. Further the role of the TIL for stratosphere-troposphere exchange (STE) is currently still under debate. In preparation of the up-coming field campaign WISE (Wave driven isentropic exchange) we explore the state and variability of the TIL over the North Atlantic between August and October in analysis model data. We use high resolution operational analysis from the European Center for Medium Range Weather Forecast to study the mesoscale structure of the TIL. The main focus is on case studies of the TIL in real baroclinic life cycles, in particular on small scale enhancements within the baroclinic disturbances and the relation to STE. Moreover, a summary is presented about the quasi climatological state of the tropopause location and sharpness over the North Atlantic over recent years.

Biofuels via Fast Pyrolysis of Perennial Grasses: A Life Cycle Evaluation of Energy Consumption and Greenhouse Gas Emissions.

PubMed

Zaimes, George G; Soratana, Kullapa; Harden, Cheyenne L; Landis, Amy E; Khanna, Vikas

2015-08-18

A well-to-wheel (WTW) life cycle assessment (LCA) model is developed to evaluate the environmental profile of producing liquid transportation fuels via fast pyrolysis of perennial grasses: switchgrass and miscanthus. The framework established in this study consists of (1) an agricultural model used to determine biomass growth rates, agrochemical application rates, and other key parameters in the production of miscanthus and switchgrass biofeedstock; (2) an ASPEN model utilized to simulate thermochemical conversion via fast pyrolysis and catalytic upgrading of bio-oil to renewable transportation fuel. Monte Carlo analysis is performed to determine statistical bounds for key sustainability and performance measures including life cycle greenhouse gas (GHG) emissions and Energy Return on Investment (EROI). The results of this work reveal that the EROI and GHG emissions (gCO2e/MJ-fuel) for fast pyrolysis derived fuels range from 1.52 to 2.56 and 22.5 to 61.0 respectively, over the host of scenarios evaluated. Further analysis reveals that the energetic performance and GHG reduction potential of fast pyrolysis-derived fuels are highly sensitive to the choice of coproduct scenario and LCA allocation scheme, and in select cases can change the life cycle carbon balance from meeting to exceeding the renewable fuel standard emissions reduction threshold for cellulosic biofuels.

A Watershed Scale Life Cycle Assessment Framework for Hydrologic Design

NASA Astrophysics Data System (ADS)

Tavakol-Davani, H.; Tavakol-Davani, PhD, H.; Burian, S. J.

2017-12-01

Sustainable hydrologic design has received attention from researchers with different backgrounds, including hydrologists and sustainability experts, recently. On one hand, hydrologists have been analyzing ways to achieve hydrologic goals through implementation of recent environmentally-friendly approaches, e.g. Green Infrastructure (GI) - without quantifying the life cycle environmental impacts of the infrastructure through the ISO Life Cycle Assessment (LCA) method. On the other hand, sustainability experts have been applying the LCA to study the life cycle impacts of water infrastructure - without considering the important hydrologic aspects through hydrologic and hydraulic (H&H) analysis. In fact, defining proper system elements for a watershed scale urban water sustainability study requires both H&H and LCA specialties, which reveals the necessity of performing an integrated, interdisciplinary study. Therefore, the present study developed a watershed scale coupled H&H-LCA framework to bring the hydrology and sustainability expertise together to contribute moving the current wage definition of sustainable hydrologic design towards onto a globally standard concept. The proposed framework was employed to study GIs for an urban watershed in Toledo, OH. Lastly, uncertainties associated with the proposed method and parameters were analyzed through a robust Monte Carlo simulation using parallel processing. Results indicated the necessity of both hydrologic and LCA components in the design procedure in order to achieve sustainability.

Common Analysis Tool Being Developed for Aeropropulsion: The National Cycle Program Within the Numerical Propulsion System Simulation Environment

NASA Technical Reports Server (NTRS)

Follen, Gregory J.; Naiman, Cynthia G.

1999-01-01

The NASA Lewis Research Center is developing an environment for analyzing and designing aircraft engines-the Numerical Propulsion System Simulation (NPSS). NPSS will integrate multiple disciplines, such as aerodynamics, structure, and heat transfer, and will make use of numerical "zooming" on component codes. Zooming is the coupling of analyses at various levels of detail. NPSS uses the latest computing and communication technologies to capture complex physical processes in a timely, cost-effective manner. The vision of NPSS is to create a "numerical test cell" enabling full engine simulations overnight on cost-effective computing platforms. Through the NASA/Industry Cooperative Effort agreement, NASA Lewis and industry partners are developing a new engine simulation called the National Cycle Program (NCP). NCP, which is the first step toward NPSS and is its initial framework, supports the aerothermodynamic system simulation process for the full life cycle of an engine. U.S. aircraft and airframe companies recognize NCP as the future industry standard common analysis tool for aeropropulsion system modeling. The estimated potential payoff for NCP is a $50 million/yr savings to industry through improved engineering productivity.

Perceptions of Organizational Effectiveness over Organizational Life Cycles.

ERIC Educational Resources Information Center

Cameron, Kim S.; Whetten, David A.

1981-01-01

Student participants at two universities played multisession simulation games involving the development of 18 organizations. Post-session surveys of 583 participants indicated that organizational effectiveness became more important to participants as the organizations developed. This suggests that future organizational effectiveness studies should…

Explicit prediction of hail using multimoment microphysics schemes for a hailstorm of 19 March 2014 in eastern China

NASA Astrophysics Data System (ADS)

Luo, Liping; Xue, Ming; Zhu, Kefeng; Zhou, Bowen

2017-07-01

In the late afternoon of 19 March 2014, a severe hailstorm swept through eastern central Zhejiang province, China. The storm produced golf ball-sized hail, strong winds, and lighting, lasting approximately 1 h over the coastal city of Taizhou. The Advanced Regional Prediction System is used to simulate the hailstorm using different configurations of the Milbrandt-Yau microphysics scheme that predict one, two, or three moments of the hydrometeor particle size distribution. Simulated fields, including accumulated precipitation and maximum estimated hail size (MESH), are verified against rain gauge observations and radar-derived MESH, respectively. For the case of the 19 March 2014 storms, the general evolution is better predicted with multimoment microphysics schemes than with the one-moment scheme; the three-moment scheme produces the best forecast. Predictions from the three-moment scheme qualitatively agree with observations in terms of size and amount of hail reaching the surface. The life cycle of the hailstorm is analyzed, using the most skillful, three-moment forecast. Based upon the tendency of surface hail mass flux, the hailstorm life cycle can be divided into three stages: developing, mature, and dissipating. Microphysical budget analyses are used to examine microphysical processes and characteristics during these three stages. The vertical structures within the storm and their link to environmental shear conditions are discussed; together with the rapid fall of hailstones, these structures and conditions appear to dictate this pulse storm's short life span. Finally, a conceptual model for the life cycle of pulse hailstorms is proposed.

Life cycle cost modeling of conceptual space vehicles

NASA Technical Reports Server (NTRS)

Ebeling, Charles

1993-01-01

This paper documents progress to date by the University of Dayton on the development of a life cycle cost model for use during the conceptual design of new launch vehicles and spacecraft. This research is being conducted under NASA Research Grant NAG-1-1327. This research effort changes the focus from that of the first two years in which a reliability and maintainability model was developed to the initial development of a life cycle cost model. Cost categories are initially patterned after NASA's three axis work breakdown structure consisting of a configuration axis (vehicle), a function axis, and a cost axis. The focus will be on operations and maintenance costs and other recurring costs. Secondary tasks performed concurrent with the development of the life cycle costing model include continual support and upgrade of the R&M model. The primary result of the completed research will be a methodology and a computer implementation of the methodology to provide for timely cost analysis in support of the conceptual design activities. The major objectives of this research are: to obtain and to develop improved methods for estimating manpower, spares, software and hardware costs, facilities costs, and other cost categories as identified by NASA personnel; to construct a life cycle cost model of a space transportation system for budget exercises and performance-cost trade-off analysis during the conceptual and development stages; to continue to support modifications and enhancements to the R&M model; and to continue to assist in the development of a simulation model to provide an integrated view of the operations and support of the proposed system.

Cycle life status of SAFT VOS nickel-cadmium cells

NASA Technical Reports Server (NTRS)

Goualard, Jacques

1993-01-01

The SAFT prismatic VOS Ni-Cd cells have been flown in geosynchronous orbit since 1977 and in low earth orbit since 1983. Parallel cycling tests are performed by several space agencies in order to determine the cycle life for a wide range of temperature and depth of discharge (DOD). In low Earth orbit (LEO), the ELAN program is conducted on 24 Ah cells by CNES and ESA at the European Battery Test Center at temperatures ranging from 0 to 27 C and DOD from 10 to 40 percent. Data are presented up to 37,000 cycles. One pack (X-80) has achieved 49,000 cycles at 10 C and 23 percent DOD. The geosynchronous orbit simulation of a high DOD test is conducted by ESA on 3 batteries at 10 C and 70, 90, and 100 percent DOD. Thirty-one eclipse seasons are completed, and no signs of degradation have been found. The Air Force test at CRANE on 24 Ah and 40 Ah cells at 20 C and 80 percent DOD has achieved 19 shadow periods. Life expectancy is discussed. The VOS cell technology could be used for the following: (1) in geosynchronous conditions--15 yrs at 10-15 C and 80 percent DOD; and (2) in low earth orbit--10 yrs at 5-15 C and 25-30 percent DOD.

MINIGENOMES, TRANSCRIPTION AND REPLICATION COMPETENT VIRUS-LIKE PARTICLES AND BEYOND: REVERSE GENETICS SYSTEMS FOR FILOVIRUSES AND OTHER NEGATIVE STRANDED HEMORRHAGIC FEVER VIRUSES

PubMed Central

Hoenen, Thomas; Groseth, Allison; de Kok-Mercado, Fabian; Kuhn, Jens H.; Wahl-Jensen, Victoria

2012-01-01

Reverse-genetics systems are powerful tools enabling researchers to study the replication cycle of RNA viruses, including filoviruses and other hemorrhagic fever viruses, as well as to discover new antivirals. They include full-length clone systems as well as a number of life cycle modeling systems. Full-length clone systems allow for the generation of infectious, recombinant viruses, and thus are an important tool for studying the virus replication cycle in its entirety. In contrast, life cycle modeling systems such as minigenome and transcription and replication competent virus-like particle systems can be used to simulate and dissect parts of the virus life cycle outside of containment facilities. Minigenome systems are used to model viral genome replication and transcription, whereas transcription and replication competent virus-like particle systems also model morphogenesis and budding as well as infection of target cells. As such, these modeling systems have tremendous potential to further the discovery and screening of new antivirals targeting hemorrhagic fever viruses. This review provides an overview of currently established reverse genetics systems for hemorrhagic fever-causing negative-sense RNA viruses, with a particular emphasis on filoviruses, and the potential application of these systems for antiviral research. PMID:21699921

The use of Tcl and Tk to improve design and code reutilization

NASA Technical Reports Server (NTRS)

Rodriguez, Lisbet; Reinholtz, Kirk

1995-01-01

Tcl and Tk facilitate design and code reuse in the ZIPSIM series of high-performance, high-fidelity spacecraft simulators. Tcl and Tk provide a framework for the construction of the Graphical User Interfaces for the simulators. The interfaces are architected such that a large proportion of the design and code is used for several applications, which has reduced design time and life-cycle costs.

Two-Dimensional Neutronic and Fuel Cycle Analysis of the Transatomic Power Molten Salt Reactor

DOE Office of Scientific and Technical Information (OSTI.GOV)

Betzler, Benjamin R.; Powers, Jeffrey J.; Worrall, Andrew

2017-01-15

This status report presents the results from the first phase of the collaboration between Transatomic Power Corporation (TAP) and Oak Ridge National Laboratory (ORNL) to provide neutronic and fuel cycle analysis of the TAP core design through the Department of Energy Gateway for Accelerated Innovation in Nuclear, Nuclear Energy Voucher program. The TAP design is a molten salt reactor using movable moderator rods to shift the neutron spectrum in the core from mostly epithermal at beginning of life to thermal at end of life. Additional developments in the ChemTriton modeling and simulation tool provide the critical moderator-to-fuel ratio searches andmore » time-dependent parameters necessary to simulate the continuously changing physics in this complex system. Results from simulations with these tools show agreement with TAP-calculated performance metrics for core lifetime, discharge burnup, and salt volume fraction, verifying the viability of reducing actinide waste production with this design. Additional analyses of time step sizes, mass feed rates and enrichments, and isotopic removals provide additional information to make informed design decisions. This work further demonstrates capabilities of ORNL modeling and simulation tools for analysis of molten salt reactor designs and strongly positions this effort for the upcoming three-dimensional core analysis.« less

Simulation and economic analysis of a liquid-based solar system with a direct-contact liquid-liquid heat exchanger, in comparison to a system with a conventional heat exchanger

NASA Astrophysics Data System (ADS)

Brothers, P.; Karaki, S.

Using a solar computer simulation package called TRNSYS, simulations of the direct contact liquid-liquid heat exchanger (DCLLHE) solar system and a system with conventional shell-and-tube heat exchanger were developed, based in part on performance measurements of the actual systems. The two systems were simulated over a full year on an hour-by-hour basis at five locations; Boston, Massachusetts, Charleston, South Carolina, Dodge City, Kansas, Madison, Wisconsin, and Phoenix, Arizona. Typically the direct-contact system supplies slightly more heat for domestic hot water and space heating in all locations and about 5 percentage points more cooling as compared to the conventional system. Using a common set of economic parameters and the appropriate federal and state income tax credits, as well as property tax legislation for solar systems in the corresponding states, the results of the study indicate for heating-only systems, the DCLLHE system has a slight life-cycle cost disadvantage compared to the conventional system. For combined solar heating and cooling systems, the DCLLHE has a slight life-cycle cost advantage which varies with location and amounts to one to three percent difference from the conventional system.

Mosquito population dynamics from cellular automata-based simulation

NASA Astrophysics Data System (ADS)

Syafarina, Inna; Sadikin, Rifki; Nuraini, Nuning

2016-02-01

In this paper we present an innovative model for simulating mosquito-vector population dynamics. The simulation consist of two stages: demography and dispersal dynamics. For demography simulation, we follow the existing model for modeling a mosquito life cycles. Moreover, we use cellular automata-based model for simulating dispersal of the vector. In simulation, each individual vector is able to move to other grid based on a random walk. Our model is also capable to represent immunity factor for each grid. We simulate the model to evaluate its correctness. Based on the simulations, we can conclude that our model is correct. However, our model need to be improved to find a realistic parameters to match real data.

An extended life and performance test of a low-power arcjet

NASA Technical Reports Server (NTRS)

Curran, Francis M.; Haag, Thomas W.

1988-01-01

An automated, cyclic life test was performed to demonstrate the reliability and endurance of a low power dc cycle arcjet thruster. Over 1000 hr and 500 on-off cycles were accumulated which would represent the requirements for about 15 years of on-orbit lifetime. A hydrogen/nitrogen propellant mixture was used to simulate decomposed hydrazine propellant and the power level was nominally 1.2 kW after the burn-in period. The arcjet operated in a very repeatable fashion from cycle to cycle. The steady state voltage increased by approximately 6 V over the first 300 hr, and then by only 3 V through the remainder of the test. Thrust measurements taken before, during, and after the test verified that the thruster performed in a consistent fashion throughout the tests at a specific impulse of 450 to 460 sec. Post-test component evaluation revealed limited erosion on both the anode and cathode. Other thruster components, including graphite seals, appeared undamaged.

Role of High-End Computing in Meeting NASA's Science and Engineering Challenges

NASA Technical Reports Server (NTRS)

Biswas, Rupak

2006-01-01

High-End Computing (HEC) has always played a major role in meeting the modeling and simulation needs of various NASA missions. With NASA's newest 62 teraflops Columbia supercomputer, HEC is having an even greater impact within the Agency and beyond. Significant cutting-edge science and engineering simulations in the areas of space exploration, Shuttle operations, Earth sciences, and aeronautics research, are already occurring on Columbia, demonstrating its ability to accelerate NASA s exploration vision. The talk will describe how the integrated supercomputing production environment is being used to reduce design cycle time, accelerate scientific discovery, conduct parametric analysis of multiple scenarios, and enhance safety during the life cycle of NASA missions.

Phenotypic Heterogeneity and the Evolution of Bacterial Life Cycles.

PubMed

van Gestel, Jordi; Nowak, Martin A

2016-02-01

Most bacteria live in colonies, where they often express different cell types. The ecological significance of these cell types and their evolutionary origin are often unknown. Here, we study the evolution of cell differentiation in the context of surface colonization. We particularly focus on the evolution of a 'sticky' cell type that is required for surface attachment, but is costly to express. The sticky cells not only facilitate their own attachment, but also that of non-sticky cells. Using individual-based simulations, we show that surface colonization rapidly evolves and in most cases leads to phenotypic heterogeneity, in which sticky and non-sticky cells occur side by side on the surface. In the presence of regulation, cell differentiation leads to a remarkable set of bacterial life cycles, in which cells alternate between living in the liquid and living on the surface. The dominant life stage is formed by the surface-attached colony that shows many complex features: colonies reproduce via fission and by producing migratory propagules; cells inside the colony divide labour; and colonies can produce filaments to facilitate expansion. Overall, our model illustrates how the evolution of an adhesive cell type goes hand in hand with the evolution of complex bacterial life cycles.

A statistical approach to the life cycle analysis of cumulus clouds selected in a virtual reality environment

NASA Astrophysics Data System (ADS)

Heus, Thijs; Jonker, Harm J. J.; van den Akker, Harry E. A.; Griffith, Eric J.; Koutek, Michal; Post, Frits H.

2009-03-01

In this study, a new method is developed to investigate the entire life cycle of shallow cumuli in large eddy simulations. Although trained observers have no problem in distinguishing the different life stages of a cloud, this process proves difficult to automate, because cloud-splitting and cloud-merging events complicate the distinction between a single system divided in several cloudy parts and two independent systems that collided. Because the human perception is well equipped to capture and to make sense of these time-dependent three-dimensional features, a combination of automated constraints and human inspection in a three-dimensional virtual reality environment is used to select clouds that are exemplary in their behavior throughout their entire life span. Three specific cases (ARM, BOMEX, and BOMEX without large-scale forcings) are analyzed in this way, and the considerable number of selected clouds warrants reliable statistics of cloud properties conditioned on the phase in their life cycle. The most dominant feature in this statistical life cycle analysis is the pulsating growth that is present throughout the entire lifetime of the cloud, independent of the case and of the large-scale forcings. The pulses are a self-sustained phenomenon, driven by a balance between buoyancy and horizontal convergence of dry air. The convective inhibition just above the cloud base plays a crucial role as a barrier for the cloud to overcome in its infancy stage, and as a buffer region later on, ensuring a steady supply of buoyancy into the cloud.

Absorptive capacity, technological innovation, and product life cycle: a system dynamics model.

PubMed

Zou, Bo; Guo, Feng; Guo, Jinyu

2016-01-01

While past research has recognized the importance of the dynamic nature of absorptive capacity, there is limited knowledge on how to generate a fair and comprehensive analytical framework. Based on interviews with 24 Chinese firms, this study develops a system-dynamics model that incorporates an important feedback loop among absorptive capacity, technological innovation, and product life cycle (PLC). The simulation results reveal that (1) PLC affects the dynamic process of absorptive capacity; (2) the absorptive capacity of a firm peaks in the growth stage of PLC, and (3) the market demand at different PLC stages is the main driving force in firms' technological innovations. This study also explores a sensitivity simulation using the variables of (1) time spent in founding an external knowledge network, (2) research and development period, and (3) knowledge diversity. The sensitivity simulation results show that the changes of these three variables have a greater impact on absorptive capacity and technological innovation during growth and maturity stages than in the introduction and declining stages of PLC. We provide suggestions on how firms can adjust management policies to improve their absorptive capacity and technological innovation performance during different PLC stages.

High Temperature Life Testing of 80Ni-20Cr Wire in a Simulated Mars Atmosphere for the Sample Analysis at Mars (SAM) Instrument Suit Gas Processing System (GPS) Carbon Dioxide Scrubber

NASA Technical Reports Server (NTRS)

Gundersen, Cynthia; Hoffman, Christopher; Munoz, Bruno; Steohenson, Timothy; Thomas, Walter

2008-01-01

In support of the GPS for the SAM instrument suite built by GSFC, a life test facility was developed to test the suitability of 80Ni-20Cr wire, 0.0056 inches in diameter, for use as a heater element for the carbon dioxide scrubber. The wire would be required to operate at 1000 C in order to attain the 800 C required for regeneration of the getter. The wire also would need to operate in the Mars atmosphere, which consists mostly of CO2 at pressures between 4 and 12 torr. Data on the high temperature degradation mechanism of 80Ni-20Cr in low pressure CO2, together with the effects of thermal cycling, were unknown. In addition, the influence of work hardening of the wire during assembly and the potential for catastrophic grain growth also were unknown. Verification of the wire reliability as defined by the mission goals required the construction of a test facility that would accurately simulate the duty cycles in a simulated Mars atmosphere. The experimental set-up, along with the test protocol and results will be described.

The tropopause inversion layer in baroclinic life cycles experiments: the role of diabatic and mixing processes

NASA Astrophysics Data System (ADS)

Kunkel, D.; Hoor, P.; Wirth, V.

2015-08-01

Recent studies on the formation of a quasi-permanent layer of enhanced static stability above the thermal tropopause revealed the contributions of dynamical and radiative processes. Dry dynamics lead to the evolution of a tropopause inversion layer (TIL) which is, however, too weak compared to observations and thus diabatic contributions are required. In this study we aim to assess the importance of diabatic as well as mixing processes in the understanding of TIL formation at midlatitudes. The non-hydrostatic model COSMO is applied in an idealized mid-latitude channel configuration to simulate baroclinic life cycles. The effect of individual diabatic, i.e. related to humidity and radiation, and turbulent processes is studied first to estimate the additional contribution of these processes to dry dynamics. In a second step these processes are stepwise included in the model to increase the complexity and finally estimate the relative importance of each process. The results suggest that including turbulence leads to a weaker TIL than in a dry reference simulation. In contrast, the TIL evolves stronger when radiation is included but the temporal occurrence is still comparable to the reference. Using various cloud schemes in the model shows that latent heat release and consecutive increased vertical motions foster an earlier and stronger appearance of the TIL than in all other life cycles. Furthermore, updrafts moisten the upper troposphere and as such increase the radiative effect from water vapor. Particularly, this process becomes more relevant for maintaining the TIL during later stages of the life cycles. Increased convergence of the vertical wind induced by updrafts and by propagating and potentially dissipating inertia-gravity waves further contributes to the enhanced stability of the lower stratosphere. Furthermore, radiative feedback of ice clouds reaching up to the tropopause is identified to potentially further affect the strength of the TIL in the region of the cloud.

The tropopause inversion layer in baroclinic life-cycle experiments: the role of diabatic processes

NASA Astrophysics Data System (ADS)

Kunkel, D.; Hoor, P.; Wirth, V.

2016-01-01

Recent studies on the formation of a quasi-permanent layer of enhanced static stability above the thermal tropopause revealed the contributions of dynamical and radiative processes. Dry dynamics leads to the evolution of a tropopause inversion layer (TIL), which is, however, too weak compared to observations and thus diabatic contributions are required. In this study we aim to assess the importance of diabatic processes in the understanding of TIL formation at midlatitudes. The non-hydrostatic model COSMO (COnsortium for Small-scale MOdelling) is applied in an idealized midlatitude channel configuration to simulate baroclinic life cycles. The effect of individual diabatic processes related to humidity, radiation, and turbulence is studied first to estimate the contribution of each of these processes to the TIL formation in addition to dry dynamics. In a second step these processes are stepwise included in the model to increase the complexity and finally estimate the relative importance of each process. The results suggest that including turbulence leads to a weaker TIL than in a dry reference simulation. In contrast, the TIL evolves stronger when radiation is included but the temporal evolution is still comparable to the reference. Using various cloud schemes in the model shows that latent heat release and consecutive increased vertical motions foster an earlier and stronger appearance of the TIL than in all other life cycles. Furthermore, updrafts moisten the upper troposphere and as such increase the radiative effect from water vapor. Particularly, this process becomes more relevant for maintaining the TIL during later stages of the life cycles. Increased convergence of the vertical wind induced by updrafts and by propagating inertia-gravity waves, which potentially dissipate, further contributes to the enhanced stability of the lower stratosphere. Finally, radiative feedback of ice clouds reaching up to the tropopause is identified to potentially further affect the strength of the TIL in the region of the clouds.

Software-Engineering Process Simulation (SEPS) model

NASA Technical Reports Server (NTRS)

Lin, C. Y.; Abdel-Hamid, T.; Sherif, J. S.

1992-01-01

The Software Engineering Process Simulation (SEPS) model is described which was developed at JPL. SEPS is a dynamic simulation model of the software project development process. It uses the feedback principles of system dynamics to simulate the dynamic interactions among various software life cycle development activities and management decision making processes. The model is designed to be a planning tool to examine tradeoffs of cost, schedule, and functionality, and to test the implications of different managerial policies on a project's outcome. Furthermore, SEPS will enable software managers to gain a better understanding of the dynamics of software project development and perform postmodern assessments.

[Prediction method of rural landscape pattern evolution based on life cycle: a case study of Jinjing Town, Hunan Province, China].

PubMed

Ji, Xiang; Liu, Li-Ming; Li, Hong-Qing

2014-11-01

Taking Jinjing Town in Dongting Lake area as a case, this paper analyzed the evolution of rural landscape patterns by means of life cycle theory, simulated the evolution cycle curve, and calculated its evolution period, then combining CA-Markov model, a complete prediction model was built based on the rule of rural landscape change. The results showed that rural settlement and paddy landscapes of Jinjing Town would change most in 2020, with the rural settlement landscape increased to 1194.01 hm2 and paddy landscape greatly reduced to 3090.24 hm2. The quantitative and spatial prediction accuracies of the model were up to 99.3% and 96.4%, respectively, being more explicit than single CA-Markov model. The prediction model of rural landscape patterns change proposed in this paper would be helpful for rural landscape planning in future.

Mathematical and experimental investigations of modeling, simulation and experiment to promote the life-cycle of polymer modified asphalt.

DOT National Transportation Integrated Search

2014-07-01

The formulation of constitutive equations for asphaltic pavement is based on rheological models which include the asphalt mixture, additives, and the bitumen. In terms of the asphalt, the rheology addresses the flow and permanent deformation in time,...

Agent-based modeling of malaria vectors: the importance of spatial simulation.

PubMed

Bomblies, Arne

2014-07-03

The modeling of malaria vector mosquito populations yields great insight into drivers of malaria transmission at the village scale. Simulation of individual mosquitoes as "agents" in a distributed, dynamic model domain may be greatly beneficial for simulation of spatial relationships of vectors and hosts. In this study, an agent-based model is used to simulate the life cycle and movement of individual malaria vector mosquitoes in a Niger Sahel village, with individual simulated mosquitoes interacting with their physical environment as well as humans. Various processes that are known to be epidemiologically important, such as the dependence of parity on flight distance between developmental habitat and blood meal hosts and therefore spatial relationships of pools and houses, are readily simulated using this modeling paradigm. Impacts of perturbations can be evaluated on the basis of vectorial capacity, because the interactions between individuals that make up the population- scale metric vectorial capacity can be easily tracked for simulated mosquitoes and human blood meal hosts, without the need to estimate vectorial capacity parameters. As expected, model results show pronounced impacts of pool source reduction from larvicide application and draining, but with varying degrees of impact depending on the spatial relationship between pools and human habitation. Results highlight the importance of spatially-explicit simulation that can model individuals such as in an agent-based model. The impacts of perturbations on village scale malaria transmission depend on spatial locations of individual mosquitoes, as well as the tracking of relevant life cycle events and characteristics of individual mosquitoes. This study demonstrates advantages of using an agent-based approach for village-scale mosquito simulation to address questions in which spatial relationships are known to be important.

Application of stochastic approach based on Monte Carlo (MC) simulation for life cycle inventory (LCI) of the rare earth elements (REEs) in beneficiation rare earth waste from the gold processing: case study

NASA Astrophysics Data System (ADS)

Bieda, Bogusław; Grzesik, Katarzyna

2017-11-01

The study proposes an stochastic approach based on Monte Carlo (MC) simulation for life cycle assessment (LCA) method limited to life cycle inventory (LCI) study for rare earth elements (REEs) recovery from the secondary materials processes production applied to the New Krankberg Mine in Sweden. The MC method is recognizes as an important tool in science and can be considered the most effective quantification approach for uncertainties. The use of stochastic approach helps to characterize the uncertainties better than deterministic method. Uncertainty of data can be expressed through a definition of probability distribution of that data (e.g. through standard deviation or variance). The data used in this study are obtained from: (i) site-specific measured or calculated data, (ii) values based on literature, (iii) the ecoinvent process "rare earth concentrate, 70% REO, from bastnäsite, at beneficiation". Environmental emissions (e.g, particulates, uranium-238, thorium-232), energy and REE (La, Ce, Nd, Pr, Sm, Dy, Eu, Tb, Y, Sc, Yb, Lu, Tm, Y, Gd) have been inventoried. The study is based on a reference case for the year 2016. The combination of MC analysis with sensitivity analysis is the best solution for quantified the uncertainty in the LCI/LCA. The reliability of LCA results may be uncertain, to a certain degree, but this uncertainty can be noticed with the help of MC method.

Comparative life cycle assessment of lignocellulosic ethanol production: biochemical versus thermochemical conversion.

PubMed

Mu, Dongyan; Seager, Thomas; Rao, P Suresh; Zhao, Fu

2010-10-01

Lignocellulosic biomass can be converted into ethanol through either biochemical or thermochemical conversion processes. Biochemical conversion involves hydrolysis and fermentation while thermochemical conversion involves gasification and catalytic synthesis. Even though these routes produce comparable amounts of ethanol and have similar energy efficiency at the plant level, little is known about their relative environmental performance from a life cycle perspective. Especially, the indirect impacts, i.e. emissions and resource consumption associated with the production of various process inputs, are largely neglected in previous studies. This article compiles material and energy flow data from process simulation models to develop life cycle inventory and compares the fossil fuel consumption, greenhouse gas emissions, and water consumption of both biomass-to-ethanol production processes. The results are presented in terms of contributions from feedstock, direct, indirect, and co-product credits for four representative biomass feedstocks i.e., wood chips, corn stover, waste paper, and wheat straw. To explore the potentials of the two conversion pathways, different technological scenarios are modeled, including current, 2012 and 2020 technology targets, as well as different production/co-production configurations. The modeling results suggest that biochemical conversion has slightly better performance on greenhouse gas emission and fossil fuel consumption, but that thermochemical conversion has significantly less direct, indirect, and life cycle water consumption. Also, if the thermochemical plant operates as a biorefinery with mixed alcohol co-products separated for chemicals, it has the potential to achieve better performance than biochemical pathway across all environmental impact categories considered due to higher co-product credits associated with chemicals being displaced. The results from this work serve as a starting point for developing full life cycle assessment model that facilitates effective decision-making regarding lignocellulosic ethanol production.

Comparative Life Cycle Assessment of Lignocellulosic Ethanol Production: Biochemical Versus Thermochemical Conversion

NASA Astrophysics Data System (ADS)

Mu, Dongyan; Seager, Thomas; Rao, P. Suresh; Zhao, Fu

2010-10-01

Lignocellulosic biomass can be converted into ethanol through either biochemical or thermochemical conversion processes. Biochemical conversion involves hydrolysis and fermentation while thermochemical conversion involves gasification and catalytic synthesis. Even though these routes produce comparable amounts of ethanol and have similar energy efficiency at the plant level, little is known about their relative environmental performance from a life cycle perspective. Especially, the indirect impacts, i.e. emissions and resource consumption associated with the production of various process inputs, are largely neglected in previous studies. This article compiles material and energy flow data from process simulation models to develop life cycle inventory and compares the fossil fuel consumption, greenhouse gas emissions, and water consumption of both biomass-to-ethanol production processes. The results are presented in terms of contributions from feedstock, direct, indirect, and co-product credits for four representative biomass feedstocks i.e., wood chips, corn stover, waste paper, and wheat straw. To explore the potentials of the two conversion pathways, different technological scenarios are modeled, including current, 2012 and 2020 technology targets, as well as different production/co-production configurations. The modeling results suggest that biochemical conversion has slightly better performance on greenhouse gas emission and fossil fuel consumption, but that thermochemical conversion has significantly less direct, indirect, and life cycle water consumption. Also, if the thermochemical plant operates as a biorefinery with mixed alcohol co-products separated for chemicals, it has the potential to achieve better performance than biochemical pathway across all environmental impact categories considered due to higher co-product credits associated with chemicals being displaced. The results from this work serve as a starting point for developing full life cycle assessment model that facilitates effective decision-making regarding lignocellulosic ethanol production.

Life-Cycle Assessment of Biodiesel Produced from Grease Trap Waste.

PubMed

Hums, Megan E; Cairncross, Richard A; Spatari, Sabrina

2016-03-01

Grease trap waste (GTW) is a low-quality waste material with variable lipid content that is an untapped resource for producing biodiesel. Compared to conventional biodiesel feedstocks, GTW requires different and additional processing steps for biodiesel production due to its heterogeneous composition, high acidity, and high sulfur content. Life-cycle assessment (LCA) is used to quantify greenhouse gas emissions, fossil energy demand, and criteria air pollutant emissions for the GTW-biodiesel process, in which the sensitivity to lipid concentration in GTW is analyzed using Monte Carlo simulation. The life-cycle environmental performance of GTW-biodiesel is compared to that of current GTW disposal, the soybean-biodiesel process, and low-sulfur diesel (LSD). The disposal of the water and solid wastes produced from separating lipids from GTW has a high contribution to the environmental impacts; however, the impacts of these processed wastes are part of the current disposal practice for GTW and could be excluded with consequential LCA system boundaries. At lipid concentrations greater than 10%, most of the environmental metrics studied are lower than those of LSD and comparable to soybean biodiesel.

Model-Based Verification and Validation of the SMAP Uplink Processes

NASA Technical Reports Server (NTRS)

Khan, M. Omair; Dubos, Gregory F.; Tirona, Joseph; Standley, Shaun

2013-01-01

This case study stands as an example of how a project can validate a system-level design earlier in the project life cycle than traditional V&V processes by using simulation on a system model. Specifically, this paper describes how simulation was added to a system model of the Soil Moisture Active-Passive (SMAP) mission's uplink process.Also discussed are the advantages and disadvantages of the methods employed and the lessons learned; which are intended to benefit future model-based and simulation-based V&V development efforts.

Nemo: an evolutionary and population genetics programming framework.

PubMed

Guillaume, Frédéric; Rougemont, Jacques

2006-10-15

Nemo is an individual-based, genetically explicit and stochastic population computer program for the simulation of population genetics and life-history trait evolution in a metapopulation context. It comes as both a C++ programming framework and an executable program file. Its object-oriented programming design gives it the flexibility and extensibility needed to implement a large variety of forward-time evolutionary models. It provides developers with abstract models allowing them to implement their own life-history traits and life-cycle events. Nemo offers a large panel of population models, from the Island model to lattice models with demographic or environmental stochasticity and a variety of already implemented traits (deleterious mutations, neutral markers and more), life-cycle events (mating, dispersal, aging, selection, etc.) and output operators for saving data and statistics. It runs on all major computer platforms including parallel computing environments. The source code, binaries and documentation are available under the GNU General Public License at http://nemo2.sourceforge.net.

Low-cycle thermal fatigue

NASA Technical Reports Server (NTRS)

Halford, G. R.

1986-01-01

A state-of-the-art review is presented of the field of thermal fatigue. Following a brief historical review, the concept is developed that thermal fatigue can be viewed as processes of unbalanced deformation and cracking. The unbalances refer to dissimilar mechanisms occurring in opposing halves of thermal fatigue loading and unloading cycles. Extensive data summaries are presented and results are interpreted in terms of the unbalanced processes involved. Both crack initiation and crack propagation results are summarized. Testing techniques are reviewed, and considerable discussion is given to a technique for thermal fatigue simulation, known as the bithermal fatigue test. Attention is given to the use of isothermal life prediction methods for the prediction of thermal fatigue lives. Shortcomings of isothermally-based life prediction methods are pointed out. Several examples of analyses and thermal fatigue life predictions of high technology structural components are presented. Finally, numerous dos and don'ts relative to design against thermal fatigue are presented.

Probabilistic performance-based design for high performance control systems

NASA Astrophysics Data System (ADS)

Micheli, Laura; Cao, Liang; Gong, Yongqiang; Cancelli, Alessandro; Laflamme, Simon; Alipour, Alice

2017-04-01

High performance control systems (HPCS) are advanced damping systems capable of high damping performance over a wide frequency bandwidth, ideal for mitigation of multi-hazards. They include active, semi-active, and hybrid damping systems. However, HPCS are more expensive than typical passive mitigation systems, rely on power and hardware (e.g., sensors, actuators) to operate, and require maintenance. In this paper, a life cycle cost analysis (LCA) approach is proposed to estimate the economic benefit these systems over the entire life of the structure. The novelty resides in the life cycle cost analysis in the performance based design (PBD) tailored to multi-level wind hazards. This yields a probabilistic performance-based design approach for HPCS. Numerical simulations are conducted on a building located in Boston, MA. LCA are conducted for passive control systems and HPCS, and the concept of controller robustness is demonstrated. Results highlight the promise of the proposed performance-based design procedure.

Thermal barrier coating life prediction model development

NASA Technical Reports Server (NTRS)

Sheffler, K. D.; Demasi, J. T.

1985-01-01

A methodology was established to predict thermal barrier coating life in an environment simulative of that experienced by gas turbine airfoils. Specifically, work is being conducted to determine failure modes of thermal barrier coatings in the aircraft engine environment. Analytical studies coupled with appropriate physical and mechanical property determinations are being employed to derive coating life prediction model(s) on the important failure mode(s). An initial review of experimental and flight service components indicates that the predominant mode of TBC failure involves thermomechanical spallation of the ceramic coating layer. This ceramic spallation involves the formation of a dominant crack in the ceramic coating parallel to and closely adjacent to the metal-ceramic interface. Initial results from a laboratory test program designed to study the influence of various driving forces such as temperature, thermal cycle frequency, environment, and coating thickness, on ceramic coating spalling life suggest that bond coat oxidation damage at the metal-ceramic interface contributes significantly to thermomechanical cracking in the ceramic layer. Low cycle rate furnace testing in air and in argon clearly shows a dramatic increase of spalling life in the non-oxidizing environments.

Fatigue life calculation of desuperheater for solving pipe cracking issue using finite element method (FEM) software

NASA Astrophysics Data System (ADS)

Kumar, Aravinda; Singh, Jeetendra Kumar; Mohan, K.

2012-06-01

Desuperheater assembly experiences thermal cycling in operation by design. During power plant's start up, load change and shut down, thermal gradient is highest. Desuperheater should be able to handle rapid ramp up or ramp down of temperature in these operations. With "hump style" two nozzle desuperheater, cracks were appearing in the pipe after only few cycles of operation. From the field data, it was clear that desuperheater is not able to handle disproportionate thermal expansion happening in the assembly during temperature ramp up and ramp down in operation and leading to cracks appearing in the piping. Growth of thermal fatigue crack is influenced by several factors including geometry, severity of thermal stress and applied mechanical load. This paper seeks to determine cause of failure of two nozzle "hump style" desuperheater using Finite Element Method (FEM) simulation technique. Thermal stress simulation and fatigue life calculation were performed using commercial FEA software "ANSYS" [from Ansys Inc, USA]. Simulation result showed that very high thermal stress is developing in the region where cracks are seen in the field. From simulation results, it is also clear that variable thermal expansion of two nozzle studs is creating high stress at the water manifold junction. A simple and viable solution is suggested by increasing the length of the manifold which solved the cracking issues in the pipe.

Dynamic Modeling of ALS Systems

NASA Technical Reports Server (NTRS)

Jones, Harry

2002-01-01

The purpose of dynamic modeling and simulation of Advanced Life Support (ALS) systems is to help design them. Static steady state systems analysis provides basic information and is necessary to guide dynamic modeling, but static analysis is not sufficient to design and compare systems. ALS systems must respond to external input variations and internal off-nominal behavior. Buffer sizing, resupply scheduling, failure response, and control system design are aspects of dynamic system design. We develop two dynamic mass flow models and use them in simulations to evaluate systems issues, optimize designs, and make system design trades. One model is of nitrogen leakage in the space station, the other is of a waste processor failure in a regenerative life support system. Most systems analyses are concerned with optimizing the cost/benefit of a system at its nominal steady-state operating point. ALS analysis must go beyond the static steady state to include dynamic system design. All life support systems exhibit behavior that varies over time. ALS systems must respond to equipment operating cycles, repair schedules, and occasional off-nominal behavior or malfunctions. Biological components, such as bioreactors, composters, and food plant growth chambers, usually have operating cycles or other complex time behavior. Buffer sizes, material stocks, and resupply rates determine dynamic system behavior and directly affect system mass and cost. Dynamic simulation is needed to avoid the extremes of costly over-design of buffers and material reserves or system failure due to insufficient buffers and lack of stored material.

Nickel hydrogen cell tests. [recharging

NASA Technical Reports Server (NTRS)

Mueller, V. C.

1981-01-01

Some parametric tests followed by cycling tests are described for the characterization of the service life of nickel hydrogen cells. Three cells were automatically cycled in simulated low Earth orbit in 35 minute discharge, 55 minute charge, with charging voltage limited, temperature compensated. The cells were mounted in a fixture that conducts heat to an aluminum baseplate. The baseplate in turn, is bounded in a temperature controlled bath to remove the heat from the mounted fixture. One cell was tested with a zircar separator, which failed after 2473 cyles. Two other cells were tested one with a zircar separator; the other with asbestos. More than 400 cycles were achieved.

Simulation of Malaria Transmission among Households in a Thai Village using Remotely Sensed Parameters

NASA Technical Reports Server (NTRS)

Kiang, Richard K.; Adimi, Farida; Zollner, Gabriela E.; Coleman, Russell E.

2007-01-01

We have used discrete-event simulation to model the malaria transmission in a Thailand village with approximately 700 residents. Specifically, we model the detailed interactions among the vector life cycle, sporogonic cycle and human infection cycle under the explicit influences of selected extrinsic and intrinsic factors. Some of the meteorological and environmental parameters used in the simulation are derived from Tropical Rainfall Measuring Mission and the Ikonos satellite data. Parameters used in the simulations reflect the realistic condition of the village, including the locations and sizes of the households, ages and estimated immunity of the residents, presence of farm animals, and locations of larval habitats. Larval habitats include the actual locations where larvae were collected and the probable locations based on satellite data. The output of the simulation includes the individual infection status and the quantities normally observed in field studies, such as mosquito biting rates, sporozoite infection rates, gametocyte prevalence and incidence. Simulated transmission under homogeneous environmental condition was compared with that predicted by a SEIR model. Sensitivity of the output with respect to some extrinsic and intrinsic factors was investigated. Results were compared with mosquito vector and human malaria data acquired over 4.5 years (June 1999 - January 2004) in Kong Mong Tha, a remote village in Kanchanaburi Province, western Thailand. The simulation method is useful for testing transmission hypotheses, estimating the efficacy of insecticide applications, assessing the impacts of nonimmune immigrants, and predicting the effects of socioeconomic, environmental and climatic changes.

Phenotypic Heterogeneity and the Evolution of Bacterial Life Cycles

PubMed Central

van Gestel, Jordi; Nowak, Martin A.

2016-01-01

Most bacteria live in colonies, where they often express different cell types. The ecological significance of these cell types and their evolutionary origin are often unknown. Here, we study the evolution of cell differentiation in the context of surface colonization. We particularly focus on the evolution of a ‘sticky’ cell type that is required for surface attachment, but is costly to express. The sticky cells not only facilitate their own attachment, but also that of non-sticky cells. Using individual-based simulations, we show that surface colonization rapidly evolves and in most cases leads to phenotypic heterogeneity, in which sticky and non-sticky cells occur side by side on the surface. In the presence of regulation, cell differentiation leads to a remarkable set of bacterial life cycles, in which cells alternate between living in the liquid and living on the surface. The dominant life stage is formed by the surface-attached colony that shows many complex features: colonies reproduce via fission and by producing migratory propagules; cells inside the colony divide labour; and colonies can produce filaments to facilitate expansion. Overall, our model illustrates how the evolution of an adhesive cell type goes hand in hand with the evolution of complex bacterial life cycles. PMID:26894881

Effects of complex life cycles on genetic diversity: cyclical parthenogenesis.

PubMed

Rouger, R; Reichel, K; Malrieu, F; Masson, J P; Stoeckel, S

2016-11-01

Neutral patterns of population genetic diversity in species with complex life cycles are difficult to anticipate. Cyclical parthenogenesis (CP), in which organisms undergo several rounds of clonal reproduction followed by a sexual event, is one such life cycle. Many species, including crop pests (aphids), human parasites (trematodes) or models used in evolutionary science (Daphnia), are cyclical parthenogens. It is therefore crucial to understand the impact of such a life cycle on neutral genetic diversity. In this paper, we describe distributions of genetic diversity under conditions of CP with various clonal phase lengths. Using a Markov chain model of CP for a single locus and individual-based simulations for two loci, our analysis first demonstrates that strong departures from full sexuality are observed after only a few generations of clonality. The convergence towards predictions made under conditions of full clonality during the clonal phase depends on the balance between mutations and genetic drift. Second, the sexual event of CP usually resets the genetic diversity at a single locus towards predictions made under full sexuality. However, this single recombination event is insufficient to reshuffle gametic phases towards full-sexuality predictions. Finally, for similar levels of clonality, CP and acyclic partial clonality (wherein a fixed proportion of individuals are clonally produced within each generation) differentially affect the distribution of genetic diversity. Overall, this work provides solid predictions of neutral genetic diversity that may serve as a null model in detecting the action of common evolutionary or demographic processes in cyclical parthenogens (for example, selection or bottlenecks).

Two-scale evaluation of remediation technologies for a contaminated site by applying economic input-output life cycle assessment: risk-cost, risk-energy consumption and risk-CO2 emission.

PubMed

Inoue, Yasushi; Katayama, Arata

2011-09-15

A two-scale evaluation concept of remediation technologies for a contaminated site was expanded by introducing life cycle costing (LCC) and economic input-output life cycle assessment (EIO-LCA). The expanded evaluation index, the rescue number for soil (RN(SOIL)) with LCC and EIO-LCA, comprises two scales, such as risk-cost, risk-energy consumption or risk-CO(2) emission of a remediation. The effectiveness of RN(SOIL) with LCC and EIO-LCA was examined in a typical contamination and remediation scenario in which dieldrin contaminated an agricultural field. Remediation was simulated using four technologies: disposal, high temperature thermal desorption, biopile and landfarming. Energy consumption and CO(2) emission were determined from a life cycle inventory analysis using monetary-based intensity based on an input-output table. The values of RN(SOIL) based on risk-cost, risk-energy consumption and risk-CO(2) emission were calculated, and then rankings of the candidates were compiled according to RN(SOIL) values. A comparison between three rankings showed the different ranking orders. The existence of differences in ranking order indicates that the scales would not have reciprocal compatibility for two-scale evaluation and that each scale should be used independently. The RN(SOIL) with LCA will be helpful in selecting a technology, provided an appropriate scale is determined. Copyright © 2011 Elsevier B.V. All rights reserved.

High Temperature Life Testing of 80Ni-20Cr Wire in a Simulated Mars Atmosphere for the Sample Analysis at Mars (SAM) Instrument Suite Gas Processing System (GPS) Carbon Dioxide Scrubber

NASA Technical Reports Server (NTRS)

Hoffman, Christopher; Munoz, Bruno; Gundersen, Cynthia; Thomas, Walter, III; Stephenson, Timothy

2008-01-01

In support of the GPS for the SAM instrument suite built by NASA/GSFC, a life test facility was developed to test the suitability of 80Ni-20Cr alloy wire, 0.0142 cm diameter, for use as a heater element for the carbon dioxide scrubber. The element would be required to operate at 1000 C in order to attain the 800 C required for regeneration of the getter. The element also would need to operate in the Mars atmosphere, which consists mostly of CO2 at pressures between 4 and 12 torr. Data on the high temperature degradation mechanism of 80Ni- 20Cr in low pressure CO2, coupled with the effects of thermal cycling, were unknown. In addition, the influence of work hardening of the wire during assembly and the potential for catastrophic grain growth also were unknown. Verification of the element reliability as defined by the mission goals required the construction of a test facility that would accurately simulate the duty cycles in a simulated Mars atmosphere. The experimental set-up, along with the test protocol and results will be described.

Development and Application of a Life Cycle-Based Model to Evaluate Greenhouse Gas Emissions of Oil Sands Upgrading Technologies.

PubMed

Pacheco, Diana M; Bergerson, Joule A; Alvarez-Majmutov, Anton; Chen, Jinwen; MacLean, Heather L

2016-12-20

A life cycle-based model, OSTUM (Oil Sands Technologies for Upgrading Model), which evaluates the energy intensity and greenhouse gas (GHG) emissions of current oil sands upgrading technologies, is developed. Upgrading converts oil sands bitumen into high quality synthetic crude oil (SCO), a refinery feedstock. OSTUM's novel attributes include the following: the breadth of technologies and upgrading operations options that can be analyzed, energy intensity and GHG emissions being estimated at the process unit level, it not being dependent on a proprietary process simulator, and use of publicly available data. OSTUM is applied to a hypothetical, but realistic, upgrading operation based on delayed coking, the most common upgrading technology, resulting in emissions of 328 kg CO 2 e/m 3 SCO. The primary contributor to upgrading emissions (45%) is the use of natural gas for hydrogen production through steam methane reforming, followed by the use of natural gas as fuel in the rest of the process units' heaters (39%). OSTUM's results are in agreement with those of a process simulation model developed by CanmetENERGY, other literature, and confidential data of a commercial upgrading operation. For the application of the model, emissions are found to be most sensitive to the amount of natural gas utilized as feedstock by the steam methane reformer. OSTUM is capable of evaluating the impact of different technologies, feedstock qualities, operating conditions, and fuel mixes on upgrading emissions, and its life cycle perspective allows easy incorporation of results into well-to-wheel analyses.

pH-Induced Stability Switching of the Bacteriophage HK97 Maturation Pathway

PubMed Central

2015-01-01

Many viruses undergo large-scale conformational changes during their life cycles. Blocking the transition from one stage of the life cycle to the next is an attractive strategy for the development of antiviral compounds. In this work, we have constructed an icosahedrally symmetric, low-energy pathway for the maturation transition of bacteriophage HK97. By conducting constant-pH molecular dynamics simulations on this pathway, we identify which residues are contributing most significantly to shifting the stability between the states along the pathway under differing pH conditions. We further analyze these data to establish the connection between critical residues and important structural motifs which undergo reorganization during maturation. We go on to show how DNA packaging can induce spontaneous reorganization of the capsid during maturation. PMID:24495192

Evolution and regulation of complex life cycles: a brown algal perspective.

PubMed

Cock, J Mark; Godfroy, Olivier; Macaisne, Nicolas; Peters, Akira F; Coelho, Susana M

2014-02-01

The life cycle of an organism is one of its fundamental features, influencing many aspects of its biology. The brown algae exhibit a diverse range of life cycles indicating that transitions between life cycle types may have been key adaptive events in the evolution of this group. Life cycle mutants, identified in the model organism Ectocarpus, are providing information about how life cycle progression is regulated at the molecular level in brown algae. We explore some of the implications of the phenotypes of the life cycle mutants described to date and draw comparisons with recent insights into life cycle regulation in the green lineage. Given the importance of coordinating growth and development with life cycle progression, we suggest that the co-option of ancient life cycle regulators to control key developmental events may be a common feature in diverse groups of multicellular eukaryotes. Copyright © 2013 Elsevier Ltd. All rights reserved.

Progress towards computer simulation of NiH2 battery performance over life

NASA Technical Reports Server (NTRS)

Zimmerman, Albert H.; Quinzio, M. V.

1995-01-01

The long-term performance of rechargeable battery cells has traditionally been verified through life-testing, a procedure that generally requires significant commitments of funding and test resources. In the situation of nickel hydrogen battery cells, which have the capability of providing extremely long cycle life, the time and cost required to conduct even accelerated testing has become a serious impediment to transitioning technology improvements into spacecraft applications. The utilization of computer simulations to indicate the changes in performance to be expected in response to design or operating changes in nickel hydrogen cells is therefore a particularly attractive tool in advanced battery development, as well as for verifying performance in different applications. Computer-based simulations of the long-term performance of rechargeable battery cells have typically had very limited success in the past. There are a number of reasons for the lack in progress in this area. First, and probably most important, all battery cells are relatively complex electrochemical systems, in which performance is dictated by a large number of interacting physical and chemical processes. While the complexity alone is a significant part of the problem, in many instances the fundamental chemical and physical processes underlying long-term degradation and its effects on performance have not even been understood. Second, while specific chemical and physical changes within cell components have been associated with degradation, there has been no generalized simulation architecture that enables the chemical and physical structure (and changes therein) to be translated into cell performance. For the nickel hydrogen battery cell, our knowledge of the underlying reactions that control the performance of this cell has progressed to where it clearly is possible to model them. The recent development of a relative generalized cell modelling approach provides the framework for translating the chemical and physical structure of the components inside a cell into its performance characteristics over its entire cycle life. This report describes our approach to this task in terms of defining those processes deemed critical in controlling performance over life, and the model architecture required to translate the fundamental cell processes into performance profiles.

Multiscale design and life-cycle based sustainability assessment of polymer nanocomposite coatings

NASA Astrophysics Data System (ADS)

Uttarwar, Rohan G.

In recent years, nanocoatings with exceptionally improved and new performance properties have found numerous applications in the automotive, aerospace, ship-making, chemical, electronics, steel, construction, and many other industries. Especially the formulations providing multiple functionalities to cured paint films are believed to dominate the coatings market in the near future. It has shifted the focus of research towards building sustainable coating recipes which can deliver multiple functionalities through applied films. The challenge to this exciting area of research arrives from the insufficient knowledge about structure-property correlations of nanocoating materials and their design complexity. Experimental efforts have been successful in developing certain types of nanopaints exhibiting improved properties. However, multifunctional nanopaint design optimality is extremely difficult to address if not impossible solely through experiments. In addition to this, the environmental implications and societal risks associated with this growing field of nanotechnology raise several questions related to its sustainable development. This research focuses on the study of a multiscale sustainable nanocoating design which can have the application from novel function envisioning and idea refinement point of view, to knowledge discovery and design solution derivation, and further to performance testing in industrial applications. The nanocoating design is studied using computational simulations of nano- to macro- scale models and sustainability assessment study over the life-cycle. Computational simulations aim at integrating top-down, goals/means, inductive systems engineering and bottom-up, cause and effect, deductive systems engineering approaches for material development. The in-silico paint resin system is a water-dispersible acrylic polymer with hydrophilic nanoparticles incorporated into it. The nano-scale atomistic and micro-scale coarse-grained (CG) level simulations are performed using molecular dynamics methodology to study several structural and morphological features such as effect of polymer molecular weight, polydispersity, rheology, nanoparticle volume fraction, size, shape and chemical nature on the bulk mechanical and self-cleaning properties of the coating film. At macro-scale, a paint spray system which is used for automotive coating application is studied by using CFD-based simulation methodology to generate crucial information about the effects of nanocoating technology on environmental emissions and coating film quality. The cradle-to-grave life-cycle based sustainability assessment study address all the critical issues related to economic benefits, environmental implications and societal effects of nanocoating technology through case studies of automotive coating systems. It is accomplished by identifying crucial correlations among measurable parameters at different stages and developing sustainability indicator matrices for analysis of each stage of life-cycle. The findings from the research can have great potential to draft useful conclusions in favor of future development of coating systems with novel functionalities and improved sustainability.

High-power UV-LED degradation: Continuous and cycled working condition influence

NASA Astrophysics Data System (ADS)

Arques-Orobon, F. J.; Nuñez, N.; Vazquez, M.; Segura-Antunez, C.; González-Posadas, V.

2015-09-01

High-power (HP) UV-LEDs can replace UV lamps for real-time fluoro-sensing applications by allowing portable and autonomous systems. However, HP UV-LEDs are not a mature technology, and there are still open issues regarding their performance evolution over time. This paper presents a reliability study of 3 W UV-LEDs, with special focus on LED degradation for two working conditions: continuous and cycled (30 s ON and 30 s OFF). Accelerated life tests are developed to evaluate the influence of temperature and electrical working conditions in high-power LEDs degradation, being the predominant failure mechanism the degradation of the package. An analysis that includes dynamic thermal and optical HP UV-LED measurements has been performed. Static thermal and stress simulation analysis with the finite element method (FEM) identifies the causes of package degradation. Accelerated life test results prove that HP UV-LEDs working in cycled condition have a better performance than those working in continuous condition.

Characterization of physiochemical properties of polymeric and electrochemical materials for aerospace flight

NASA Technical Reports Server (NTRS)

Rock, M.; Kunigahalli, V.; Khan, S.; Mcnair, A.

1984-01-01

Nickel-cadmium rechargeable batteries are a vital and reliable energy storage source for aerospace applications. As the demand for longer life and more reliable space batteries increases, the understanding and solving of cell aging factors and mechanisms become essential. Over the years, many cell designs and manufacturing process changes have been developed and implemented. Cells fabricated with various design features were life cycled in a simulated low-Earth orbit regime. Following the test program, a comprehensive electrochemical analysis of cell components was undertaken to study cell degradation mechanisms. Discharge voltage degradation or voltage plateau has been observed during orbit cycling, but, its cause and explanation have been the subject of much discussion. A Hg/HgO reference electrode was used to monitor the reference versus each electrode potential during the discharge of a cycled cell. The results indicate that the negative electrode was responsible for the voltage plateau. Cell analysis revealed large crystals of cadmium hydroxide on the surface of the negative electrode and throughout the separator.

Mercury Conditions for the MESSENGER Mission Simulated in High- Solar-Radiation Vacuum Tests

NASA Technical Reports Server (NTRS)

Wong, Wayne A.

2003-01-01

The MESSENGER (Mercury Surface, Space Environment, Geochemistry, and Ranging) spacecraft, planned for launch in March 2004, will perform two flybys of Mercury before entering a year-long orbit of the planet in September 2009. The mission will provide opportunities for detailed characterization of the surface, interior, atmosphere, and magnetosphere of the closest planet to the Sun. The NASA Glenn Research Center and the MESSENGER spacecraft integrator, the Johns Hopkins University Applied Physics Laboratory, have partnered under a Space Act Agreement to characterize a variety of critical components and materials under simulated conditions expected near Mercury. Glenn's Vacuum Facility 6, which is equipped with a solar simulator, can simulate the vacuum and high solar radiation anticipated in Mercury orbit. The MESSENGER test hardware includes a variety of materials and components that are being characterized during the Tank 6 vacuum tests, where the hardware will be exposed to up to 11 suns insolation, simulating conditions expected in Mercury orbit. In 2002, ten solar vacuum tests were conducted, including beginning of life, end of life, backside exposure, and solar panel thermal shock cycling tests. Components tested include candidate solar array panels, sensors, thermal shielding materials, and communication devices. As an example, for the solar panel thermal shock cycling test, two candidate solar array panels were suspended on a lift mechanism that lowered the panels into a liquid-nitrogen-cooled box. After reaching -140 C, the panels were then lifted out of the box and exposed to the equivalent of 6 suns (8.1 kilowatts per square meters). After five cold soak/heating cycles were completed successfully, there was no apparent degradation in panel performance. An anticipated 100-hr thermal shield life test is planned for autumn, followed by solar panel flight qualification tests in winter. Glenn's ongoing support to the MESSENGER program has been instrumental in identifying design solutions and validating thermal performance models under a very aggressive development schedule. The test data have assisted Johns Hopkins engineers in selecting a flight solar array vendor and a thermal shield design. MESSENGER is one in a series of missions in NASA's Discovery Program. Infrared thermography provides data on the thermal gradients in the MESSENGER components during high solar insolation vacuum testing.

Climate-methane cycle feedback in global climate model model simulations forced by RCP scenarios

NASA Astrophysics Data System (ADS)

Eliseev, Alexey V.; Denisov, Sergey N.; Arzhanov, Maxim M.; Mokhov, Igor I.

2013-04-01

Methane cycle module of the global climate model of intermediate complexity developed at the A.M. Obukhov Institute of Atmospheric Physics, Russian Academy of Sciences (IAP RAS CM) is extended by coupling with a detailed module for thermal and hydrological processes in soil (Deep Soil Simulator, (Arzhanov et al., 2008)). This is an important improvement with respect with the earlier IAP RAS CM version (Eliseev et al., 2008) which has employed prescribed soil hydrology to simulate CH4 emissions from soil. Geographical distribution of water inundated soil in the model was also improved by replacing the older Olson's ecosystem data base by the data based on the SCIAMACHY retrievals (Bergamaschi et al., 2007). New version of the IAP RAS CM module for methane emissions from soil is validated by using the simulation protocol adopted in the WETCHIMP (Wetland and Wetland CH4 Inter-comparison of Models Project). In addition, atmospheric part of the IAP RAS CM methane cycle is extended by temperature dependence of the methane life-time in the atmosphere in order to mimic the respective dependence of the atmospheric methane chemistry (Denisov et al., 2012). The IAP RAS CM simulations are performed for the 18th-21st centuries according with the CMIP5 protocol taking into account natural and anthropogenic forcings. The new IAP RAS CM version realistically reproduces pre-industrial and present-day characteristics of the global methane cycle including CH4 concentration qCH4 in the atmosphere and CH4 emissions from soil. The latter amounts 150 - 160 TgCH4-yr for the late 20th century and increases to 170 - 230 TgCH4-yr in the late 21st century. Atmospheric methane concentration equals 3900 ppbv under the most aggressive anthropogenic scenario RCP 8.5 and 1850 - 1980 ppbv under more moderate scenarios RCP 6.0 and RCP 4.5. Under the least aggressive scenario RCP 2.6 qCH4 reaches maximum 1730 ppbv in 2020s and declines afterwards. Climate change impact on the methane emissions from soil enhances build up of the methane stock in the atmosphere by 10 - 25% depending on anthropogenic scenario and time instant. In turn, decrease of methane life-time in the atmosphere suppresses this build up by 5 - 40%. The net effect is uncertain but small in terms of resulting additional greenhouse radiative forcing. This smallness is reflected in small additional (relative to the model version with both methane emissions from soil and methane life-time in the atmosphere fixed at their preindustrial values) near-surface warming which globally is not larger than 1 K, i.e, ˜ 4% of warming exhibited by the model version neglecting climate-methane cycle interaction. References [1] M.M. Arzhanov, P.F. Demchenko, A.V. Eliseev, and I.I. Mokhov. Simulation of characteristics of thermal and hydrologic soil regimes in equilibrium numerical experiments with a climate model of intermediate complexity. Izvestiya, Atmos. Ocean. Phys., 44(5):279-287, 2008. doi: 10.1134/S0001433808050022. [2] P. Bergamaschi, C. Frankenberg, J.F. Meirink, M. Krol, F. Dentener, T. Wagner, U. Platt, J.O. Kaplan, S. Körner, M. Heimann, E.J. Dlugokencky, and A. Goede. Satellite chartography of atmospheric methane from SCIAMACHY on board ENVISAT: 2. Evaluation based on inverse model simulations. J. Geophys. Res., 112(D2):D02304, 2007. doi: 10.1029/2006JD007268. [3] S.N. Denisov, A.V. Eliseev, and I.I. Mokhov. Climate change in the IAP RAS global model with interactive methane cycle under RCP anthropogenic scenarios. Rus. Meteorol. Hydrol., 2012. [submitted]. [4] A.V. Eliseev, I.I. Mokhov, M.M. Arzhanov, P.F. Demchenko, and S.N. Denisov. Interaction of the methane cycle and processes in wetland ecosystems in a climate model of intermediate complexity. Izvestiya, Atmos. Ocean. Phys., 44(2):139-152, 2008. doi: 10.1134/S0001433808020011.

A Framework for Statewide Analysis of Site Suitability, Energy Estimation, Life Cycle Costs, Financial Feasibility and Environmental Assessment of Wind Farms: A Case Study of Indiana

NASA Astrophysics Data System (ADS)

Kumar, Indraneel

In the last decade, Midwestern states including Indiana have experienced an unprecedented growth in utility scale wind energy farms. For example, by end of 2013, Indiana had 1.5 GW of wind turbines installed, which could provide electrical energy for as many as half-a-million homes. However, there is no statewide systematic framework available for the evaluation of wind farm impacts on endangered species, required necessary setbacks and proximity standards to infrastructure, and life cycle costs. This research is guided to fill that gap and it addresses the following questions. How much land is suitable for wind farm siting in Indiana given the constraints of environmental, ecological, cultural, settlement, physical infrastructure and wind resource parameters? How much wind energy can be obtained? What are the life cycle costs and economic and financial feasibility? Is wind energy production and development in a state an emission free undertaking? The framework developed in the study is applied to a case study of Indiana. A fuzzy logic based AHP (Analytic Hierarchy Process) spatial site suitability analysis for wind energy is formulated. The magnitude of wind energy that could be sited and installed comprises input for economic and financial feasibility analysis for 20-25 years life cycle of wind turbines in Indiana. Monte Carlo simulation is used to account for uncertainty and nonlinearity in various costs and price parameters. Impacts of incentives and cost variables such as production tax credits, costs of capital, and economies of scale are assessed. Further, an economic input-output (IO) based environmental assessment model is developed for wind energy, where costs from financial feasibility analysis constitute the final demand vectors. This customized model for Indiana is used to assess emissions for criteria air pollutants, hazardous air pollutants and greenhouse gases (GHG) across life cycle events of wind turbines. The findings of the case study include that, Indiana has adequate suitable land area available to locate wind farms with installed capacity between 11 and 51 GW if 100 meters high turbines are used. For a 1.5 MW standard wind turbine, financial feasibility analysis shows that production tax credits and property tax abatements are helpful for financial success in Indiana. Also, the wind energy is not entirely emission free if life cycle events of wind turbine manufacturing, production, installation, construction and decommissioning are considered. The research developed a replicable and integrated framework for statewide life cycle analysis of wind energy production accounting for uncertainty into the analyses. Considering the complexity of life cycle analysis and lack of state specific data on performance of wind turbines and wind farms, this study should be considered an intermediate step.

Physics based modeling of a series parallel battery pack for asymmetry analysis, predictive control and life extension

NASA Astrophysics Data System (ADS)

Ganesan, Nandhini; Basu, Suman; Hariharan, Krishnan S.; Kolake, Subramanya Mayya; Song, Taewon; Yeo, Taejung; Sohn, Dong Kee; Doo, Seokgwang

2016-08-01

Lithium-Ion batteries used for electric vehicle applications are subject to large currents and various operation conditions, making battery pack design and life extension a challenging problem. With increase in complexity, modeling and simulation can lead to insights that ensure optimal performance and life extension. In this manuscript, an electrochemical-thermal (ECT) coupled model for a 6 series × 5 parallel pack is developed for Li ion cells with NCA/C electrodes and validated against experimental data. Contribution of the cathode to overall degradation at various operating conditions is assessed. Pack asymmetry is analyzed from a design and an operational perspective. Design based asymmetry leads to a new approach of obtaining the individual cell responses of the pack from an average ECT output. Operational asymmetry is demonstrated in terms of effects of thermal gradients on cycle life, and an efficient model predictive control technique is developed. Concept of reconfigurable battery pack is studied using detailed simulations that can be used for effective monitoring and extension of battery pack life.

Waste-to-energy: A review of life cycle assessment and its extension methods.

PubMed

Zhou, Zhaozhi; Tang, Yuanjun; Chi, Yong; Ni, Mingjiang; Buekens, Alfons

2018-01-01

This article proposes a comprehensive review of evaluation tools based on life cycle thinking, as applied to waste-to-energy. Habitually, life cycle assessment is adopted to assess environmental burdens associated with waste-to-energy initiatives. Based on this framework, several extension methods have been developed to focus on specific aspects: Exergetic life cycle assessment for reducing resource depletion, life cycle costing for evaluating its economic burden, and social life cycle assessment for recording its social impacts. Additionally, the environment-energy-economy model integrates both life cycle assessment and life cycle costing methods and judges simultaneously these three features for sustainable waste-to-energy conversion. Life cycle assessment is sufficiently developed on waste-to-energy with concrete data inventory and sensitivity analysis, although the data and model uncertainty are unavoidable. Compared with life cycle assessment, only a few evaluations are conducted to waste-to-energy techniques by using extension methods and its methodology and application need to be further developed. Finally, this article succinctly summarises some recommendations for further research.

A novel quantitative model of cell cycle progression based on cyclin-dependent kinases activity and population balances.

PubMed

Pisu, Massimo; Concas, Alessandro; Cao, Giacomo

2015-04-01

Cell cycle regulates proliferative cell capacity under normal or pathologic conditions, and in general it governs all in vivo/in vitro cell growth and proliferation processes. Mathematical simulation by means of reliable and predictive models represents an important tool to interpret experiment results, to facilitate the definition of the optimal operating conditions for in vitro cultivation, or to predict the effect of a specific drug in normal/pathologic mammalian cells. Along these lines, a novel model of cell cycle progression is proposed in this work. Specifically, it is based on a population balance (PB) approach that allows one to quantitatively describe cell cycle progression through the different phases experienced by each cell of the entire population during its own life. The transition between two consecutive cell cycle phases is simulated by taking advantage of the biochemical kinetic model developed by Gérard and Goldbeter (2009) which involves cyclin-dependent kinases (CDKs) whose regulation is achieved through a variety of mechanisms that include association with cyclins and protein inhibitors, phosphorylation-dephosphorylation, and cyclin synthesis or degradation. This biochemical model properly describes the entire cell cycle of mammalian cells by maintaining a sufficient level of detail useful to identify check point for transition and to estimate phase duration required by PB. Specific examples are discussed to illustrate the ability of the proposed model to simulate the effect of drugs for in vitro trials of interest in oncology, regenerative medicine and tissue engineering. Copyright © 2015 Elsevier Ltd. All rights reserved.

Million Trees Los Angeles: Carbon dioxide sink or source?

Treesearch

E.G. McPherson; A. Kendall; S. Albers

2015-01-01

This study seeks to answer the question, 'Will the Million Trees LA (MTLA) programme be a CO2 sink or source?' Using surveys, interviews, field sampling and computer simulation of tree growth and survival over a 40-year period, we developed the first process-based life cycle inventory of CO2 for a large tree...

Modeling atmospheric effects - an assessment of the problems

Treesearch

Douglas G. Fox

1976-01-01

Our ability to simulate atmospheric processes that affect the life cycle of pollution is reviewed. The transport process is considered on three scales (a) the near-source or single-plume dispersion problem, (b) the multiple-source dispersion problem, and (c) the long-range transport. Modeling the first of these is shown to be well within the capability of generally...

Integrated computational materials engineering: Tools, simulations and new applications

DOE PAGES

Madison, Jonathan D.

2016-03-30

Here, Integrated Computational Materials Engineering (ICME) is a relatively new methodology full of tremendous potential to revolutionize how science, engineering and manufacturing work together. ICME was motivated by the desire to derive greater understanding throughout each portion of the development life cycle of materials, while simultaneously reducing the time between discovery to implementation [1,2].

Embedding Research in a Field-Based Module through Peer Review and Assessment for Learning

ERIC Educational Resources Information Center

Nicholson, Dawn T.

2011-01-01

A case study is presented of embedding research in a final year undergraduate, field-based, physical geography module. The approach is holistic, whereby research-based learning activities simulate the full life cycle of research from inception through to peer review and publication. The learning, teaching and assessment strategy emphasizes the…

A deterministic computer simulation model of life-cycle lamb and wool production.

PubMed

Wang, C T; Dickerson, G E

1991-11-01

A deterministic mathematical computer model was developed to simulate effects on life-cycle efficiency of lamb and wool production from genetic improvement of performance traits under alternative management systems. Genetic input parameters can be varied for age at puberty, length of anestrus, fertility, precocity of fertility, number born, milk yield, mortality, growth rate, body fat, and wool growth. Management options include mating systems, lambing intervals, feeding levels, creep feeding, weaning age, marketing age or weight, and culling policy. Simulated growth of animals is linear from birth to inflection point, then slows asymptotically to specified mature empty BW and fat content when nutrition is not limiting. The ME intake requirement to maintain normal condition is calculated daily or weekly for maintenance, protein and fat deposition, wool growth, gestation, and lactation. Simulated feed intake is the minimum of availability, DM physical limit, or ME physiological limit. Tissue catabolism occurs when intake is below the requirement for essential functions. Mortality increases when BW is depressed. Equations developed for calculations of biological functions were validated with published and unpublished experimental data. Lifetime totals are accumulated for TDN, DM, and protein intake and for market lamb equivalent output values of empty body or carcass lean and wool from both lambs and ewes. These measures of efficiency for combinations of genetic, management, and marketing variables can provide the relative economic weighting of traits needed to derive optimal criteria for genetic selection among and within breeds under defined industry production systems.

Application of stochastic approach based on Monte Carlo (MC) simulation for life cycle inventory (LCI) to the steel process chain: case study.

PubMed

Bieda, Bogusław

2014-05-15

The purpose of the paper is to present the results of application of stochastic approach based on Monte Carlo (MC) simulation for life cycle inventory (LCI) data of Mittal Steel Poland (MSP) complex in Kraków, Poland. In order to assess the uncertainty, the software CrystalBall® (CB), which is associated with Microsoft® Excel spreadsheet model, is used. The framework of the study was originally carried out for 2005. The total production of steel, coke, pig iron, sinter, slabs from continuous steel casting (CSC), sheets from hot rolling mill (HRM) and blast furnace gas, collected in 2005 from MSP was analyzed and used for MC simulation of the LCI model. In order to describe random nature of all main products used in this study, normal distribution has been applied. The results of the simulation (10,000 trials) performed with the use of CB consist of frequency charts and statistical reports. The results of this study can be used as the first step in performing a full LCA analysis in the steel industry. Further, it is concluded that the stochastic approach is a powerful method for quantifying parameter uncertainty in LCA/LCI studies and it can be applied to any steel industry. The results obtained from this study can help practitioners and decision-makers in the steel production management. Copyright © 2013 Elsevier B.V. All rights reserved.

10 CFR 436.12 - Life cycle cost methodology.

Code of Federal Regulations, 2012 CFR

2012-01-01

... 10 Energy 3 2012-01-01 2012-01-01 false Life cycle cost methodology. 436.12 Section 436.12 Energy DEPARTMENT OF ENERGY ENERGY CONSERVATION FEDERAL ENERGY MANAGEMENT AND PLANNING PROGRAMS Methodology and Procedures for Life Cycle Cost Analyses § 436.12 Life cycle cost methodology. The life cycle cost methodology...

10 CFR 436.12 - Life cycle cost methodology.

Code of Federal Regulations, 2014 CFR

2014-01-01

... 10 Energy 3 2014-01-01 2014-01-01 false Life cycle cost methodology. 436.12 Section 436.12 Energy DEPARTMENT OF ENERGY ENERGY CONSERVATION FEDERAL ENERGY MANAGEMENT AND PLANNING PROGRAMS Methodology and Procedures for Life Cycle Cost Analyses § 436.12 Life cycle cost methodology. The life cycle cost methodology...

10 CFR 436.12 - Life cycle cost methodology.

Code of Federal Regulations, 2013 CFR

2013-01-01

... 10 Energy 3 2013-01-01 2013-01-01 false Life cycle cost methodology. 436.12 Section 436.12 Energy DEPARTMENT OF ENERGY ENERGY CONSERVATION FEDERAL ENERGY MANAGEMENT AND PLANNING PROGRAMS Methodology and Procedures for Life Cycle Cost Analyses § 436.12 Life cycle cost methodology. The life cycle cost methodology...

10 CFR 436.12 - Life cycle cost methodology.

Code of Federal Regulations, 2010 CFR

2010-01-01

... 10 Energy 3 2010-01-01 2010-01-01 false Life cycle cost methodology. 436.12 Section 436.12 Energy DEPARTMENT OF ENERGY ENERGY CONSERVATION FEDERAL ENERGY MANAGEMENT AND PLANNING PROGRAMS Methodology and Procedures for Life Cycle Cost Analyses § 436.12 Life cycle cost methodology. The life cycle cost methodology...

10 CFR 436.19 - Life cycle costs.

Code of Federal Regulations, 2011 CFR

2011-01-01

... 10 Energy 3 2011-01-01 2011-01-01 false Life cycle costs. 436.19 Section 436.19 Energy DEPARTMENT OF ENERGY ENERGY CONSERVATION FEDERAL ENERGY MANAGEMENT AND PLANNING PROGRAMS Methodology and Procedures for Life Cycle Cost Analyses § 436.19 Life cycle costs. Life cycle costs are the sum of the...

10 CFR 436.12 - Life cycle cost methodology.

Code of Federal Regulations, 2011 CFR

2011-01-01

... 10 Energy 3 2011-01-01 2011-01-01 false Life cycle cost methodology. 436.12 Section 436.12 Energy DEPARTMENT OF ENERGY ENERGY CONSERVATION FEDERAL ENERGY MANAGEMENT AND PLANNING PROGRAMS Methodology and Procedures for Life Cycle Cost Analyses § 436.12 Life cycle cost methodology. The life cycle cost methodology...

10 CFR 436.19 - Life cycle costs.

Code of Federal Regulations, 2010 CFR

2010-01-01

... 10 Energy 3 2010-01-01 2010-01-01 false Life cycle costs. 436.19 Section 436.19 Energy DEPARTMENT OF ENERGY ENERGY CONSERVATION FEDERAL ENERGY MANAGEMENT AND PLANNING PROGRAMS Methodology and Procedures for Life Cycle Cost Analyses § 436.19 Life cycle costs. Life cycle costs are the sum of the...

The evolution of life cycle complexity in aphids: Ecological optimization or historical constraint?

PubMed

Hardy, Nate B; Peterson, Daniel A; von Dohlen, Carol D

2015-06-01

For decades, biologists have debated why many parasites have obligate multihost life cycles. Here, we use comparative phylogenetic analyses of aphids to evaluate the roles of ecological optimization and historical constraint in the evolution of life cycle complexity. If life cycle complexity is adaptive, it should be evolutionarily labile, that is, change in response to selection. We provide evidence that this is true in some aphids (aphidines), but not others (nonaphidines)-groups that differ in the intensity of their relationships with primary hosts. Next, we test specific mechanisms by which life cycle complexity could be adaptive or a constraint. We find that among aphidines there is a strong association between complex life cycles and polyphagy but only a weak correlation between life cycle complexity and reproductive mode. In contrast, among nonaphidines the relationship between life cycle complexity and host breadth is weak but the association between complex life cycles and sexual reproduction is strong. Thus, although the adaptiveness of life cycle complexity appears to be lineage specific, across aphids, life cycle evolution appears to be tightly linked with the evolution of other important natural history traits. © 2015 The Author(s). Evolution © 2015 The Society for the Study of Evolution.

Life cycle assessment of metals: a scientific synthesis.

PubMed

Nuss, Philip; Eckelman, Matthew J

2014-01-01

We have assembled extensive information on the cradle-to-gate environmental burdens of 63 metals in their major use forms, and illustrated the interconnectedness of metal production systems. Related cumulative energy use, global warming potential, human health implications and ecosystem damage are estimated by metal life cycle stage (i.e., mining, purification, and refining). For some elements, these are the first life cycle estimates of environmental impacts reported in the literature. We show that, if compared on a per kilogram basis, the platinum group metals and gold display the highest environmental burdens, while many of the major industrial metals (e.g., iron, manganese, titanium) are found at the lower end of the environmental impacts scale. If compared on the basis of their global annual production in 2008, iron and aluminum display the largest impacts, and thallium and tellurium the lowest. With the exception of a few metals, environmental impacts of the majority of elements are dominated by the purification and refining stages in which metals are transformed from a concentrate into their metallic form. Out of the 63 metals investigated, 42 metals are obtained as co-products in multi output processes. We test the sensitivity of varying allocation rationales, in which the environmental burden are allocated to the various metal and mineral products, on the overall results. Monte-Carlo simulation is applied to further investigate the stability of our results. This analysis is the most comprehensive life cycle comparison of metals to date and allows for the first time a complete bottom-up estimate of life cycle impacts of the metals and mining sector globally. We estimate global direct and indirect greenhouse gas emissions in 2008 at 3.4 Gt CO2-eq per year and primary energy use at 49 EJ per year (9.5% of global use), and report the shares for all metals to both impact categories.

Life Cycle Assessment of Metals: A Scientific Synthesis

PubMed Central

Nuss, Philip; Eckelman, Matthew J.

2014-01-01

We have assembled extensive information on the cradle-to-gate environmental burdens of 63 metals in their major use forms, and illustrated the interconnectedness of metal production systems. Related cumulative energy use, global warming potential, human health implications and ecosystem damage are estimated by metal life cycle stage (i.e., mining, purification, and refining). For some elements, these are the first life cycle estimates of environmental impacts reported in the literature. We show that, if compared on a per kilogram basis, the platinum group metals and gold display the highest environmental burdens, while many of the major industrial metals (e.g., iron, manganese, titanium) are found at the lower end of the environmental impacts scale. If compared on the basis of their global annual production in 2008, iron and aluminum display the largest impacts, and thallium and tellurium the lowest. With the exception of a few metals, environmental impacts of the majority of elements are dominated by the purification and refining stages in which metals are transformed from a concentrate into their metallic form. Out of the 63 metals investigated, 42 metals are obtained as co-products in multi output processes. We test the sensitivity of varying allocation rationales, in which the environmental burden are allocated to the various metal and mineral products, on the overall results. Monte-Carlo simulation is applied to further investigate the stability of our results. This analysis is the most comprehensive life cycle comparison of metals to date and allows for the first time a complete bottom-up estimate of life cycle impacts of the metals and mining sector globally. We estimate global direct and indirect greenhouse gas emissions in 2008 at 3.4 Gt CO2-eq per year and primary energy use at 49 EJ per year (9.5% of global use), and report the shares for all metals to both impact categories. PMID:24999810

Comparative life cycle assessment of standard and green roofs.

PubMed

Saiz, Susana; Kennedy, Christopher; Bass, Brad; Pressnail, Kim

2006-07-01

Life cycle assessment (LCA) is used to evaluate the benefits, primarily from reduced energy consumption, resulting from the addition of a green roof to an eight story residential building in Madrid. Building energy use is simulated and a bottom-up LCA is conducted assuming a 50 year building life. The key property of a green roof is its low solar absorptance, which causes lower surface temperature, thereby reducing the heat flux through the roof. Savings in annual energy use are just over 1%, but summer cooling load is reduced by over 6% and reductions in peak hour cooling load in the upper floors reach 25%. By replacing the common flat roof with a green roof, environmental impacts are reduced by between 1.0 and 5.3%. Similar reductions might be achieved by using a white roof with additional insulation for winter, but more substantial reductions are achieved if common use of green roofs leads to reductions in the urban heat island.

Conductive plastics: comparing alternative nanotechnologies by performance and life cycle release probability

NASA Astrophysics Data System (ADS)

Neubauer, Nicole; Wohlleben, Wendel; Tomović, Željko

2017-03-01

Nanocomposites can be considered safe during their life cycle as long as the nanofillers remain embedded in the matrix. Therefore, a possible release of nanofillers has to be assessed before commercialization. This report addresses possible life cycle release scenarios for carbon nanotubes (CNT), graphene, and carbon black (CB) from a thermoplastic polyurethane (TPU) matrix. The content of each nanofiller was adjusted to achieve the same conductivity level. The nanofillers reduced the rate of nanoscale releases during mechanical processing with decreasing release in the order neat TPU, TPU-CNT, TPU-graphene, and TPU-CB. Released fragments were dominated by the polymer matrix with embedded or surface-protruding nanofillers. During electron microscopy analysis, free CB was observed, however, there was no free CNT or graphene. Quantitatively, the presence of free nanofillers remained below the detection limit of <0.01% of generated dust. Further, both the production process and type of mechanical processing showed a significant impact with higher release rates for injection-molded compared to extruded and sanded compared to drilled materials. Due to its optimal performance for further development, extruded TPU-CNT was investigated in a combined, stepwise worst case scenario (mechanical processing after weathering). After weathering by simulated sunlight and rain, CNT were visible at the surface of the nanocomposite; after additional sanding, fragments showed protruding CNT, but free CNT were not detected. In summary, this preliminary exposure assessment showed no indication that recommended occupational exposure limits for carbonaceous nanomaterials can be exceeded during the life cycle of the specific TPU nanocomposites and conditions investigated in this study.

Effects of complex life cycles on genetic diversity: cyclical parthenogenesis

PubMed Central

Rouger, R; Reichel, K; Malrieu, F; Masson, J P; Stoeckel, S

2016-01-01

Neutral patterns of population genetic diversity in species with complex life cycles are difficult to anticipate. Cyclical parthenogenesis (CP), in which organisms undergo several rounds of clonal reproduction followed by a sexual event, is one such life cycle. Many species, including crop pests (aphids), human parasites (trematodes) or models used in evolutionary science (Daphnia), are cyclical parthenogens. It is therefore crucial to understand the impact of such a life cycle on neutral genetic diversity. In this paper, we describe distributions of genetic diversity under conditions of CP with various clonal phase lengths. Using a Markov chain model of CP for a single locus and individual-based simulations for two loci, our analysis first demonstrates that strong departures from full sexuality are observed after only a few generations of clonality. The convergence towards predictions made under conditions of full clonality during the clonal phase depends on the balance between mutations and genetic drift. Second, the sexual event of CP usually resets the genetic diversity at a single locus towards predictions made under full sexuality. However, this single recombination event is insufficient to reshuffle gametic phases towards full-sexuality predictions. Finally, for similar levels of clonality, CP and acyclic partial clonality (wherein a fixed proportion of individuals are clonally produced within each generation) differentially affect the distribution of genetic diversity. Overall, this work provides solid predictions of neutral genetic diversity that may serve as a null model in detecting the action of common evolutionary or demographic processes in cyclical parthenogens (for example, selection or bottlenecks). PMID:27436524

A Predictive Framework for Thermomechanical Fatigue Life of High Silicon Molybdenum Ductile Cast Iron Based on Considerations of Strain Energy Dissipation

NASA Astrophysics Data System (ADS)

Avery, Katherine R.

Isothermal low cycle fatigue (LCF) and anisothermal thermomechanical fatigue (TMF) tests were conducted on a high silicon molybdenum (HiSiMo) cast iron for temperatures up to 1073K. LCF and out-of-phase (OP) TMF lives were significantly reduced when the temperature was near 673K due to an embrittlement phenomenon which decreases the ductility of HiSiMo at this temperature. In this case, intergranular fracture was predominant, and magnesium was observed at the fracture surface. When the thermal cycle did not include 673K, the failure mode was predominantly transgranular, and magnesium was not present on the fracture surface. The in-phase (IP) TMF lives were unaffected when the thermal cycle included 673K, and the predominant failure mode was found to be transgranular fracture, regardless of the temperature. No magnesium was present on the IP TMF fracture surfaces. Thus, the embrittlement phenomenon was found to contribute to fatigue damage only when the temperature was near 673K and a tensile stress was present. To account for the temperature- and stress-dependence of the embrittlement phenomenon on the TMF life of HiSiMo cast iron, an original model based on the cyclic inelastic energy dissipation is proposed which accounts for temperature-dependent differences in the rate of fatigue damage accumulation in tension and compression. The proposed model has few empirical parameters. Despite the simplicity of the model, the predicted fatigue life shows good agreement with more than 130 uniaxial low cycle and thermomechanical fatigue tests, cyclic creep tests, and tests conducted at slow strain rates and with hold times. The proposed model was implemented in a multiaxial formulation and applied to the fatigue life prediction of an exhaust manifold subjected to severe thermal cycles. The simulation results show good agreement with the failure locations and number of cycles to failure observed in a component-level experiment.

Viscoplastic analysis of an experimental cylindrical thrust chamber liner

NASA Technical Reports Server (NTRS)

Arya, Vinod K.; Arnold, Steven M.

1991-01-01

A viscoplastic stress-strain analysis of an experimental cylindrical thrust chamber is presented. A viscoelastic constitutive model incorporating a single internal state variable that represents kinematic hardening was employed to investigate whether such a viscoplastic model could predict the experimentally observed behavior of the thrust chamber. Two types of loading cycles were considered: a short cycle of 3.5 sec. duration that corresponded to the experiments, and an extended loading cycle of 485.1 sec. duration that is typical of the Space Shuttle Main Engine (SSME) operating cycle. The analysis qualitatively replicated the deformation behavior of the component as observed in experiments designed to simulate SSME operating conditions. The analysis also showed that the mode and location in the component may depend on the loading cycle. The results indicate that using viscoplastic models for structural analysis can lead to a more realistic life assessment of thrust chambers.

How life affects the geochemical cycle of carbon

NASA Technical Reports Server (NTRS)

Walker, James C. G.

1992-01-01

Developing a quantitative understanding of the biogeochemical cycles of carbon as they have worked throughout Earth history on various time scales, how they have been affected by biological evolution, and how changes in the carbon content of ocean and atmosphere may have affected climate and the evolution of life are the goals of the research. Theoretical simulations were developed that can be tuned to reproduce such data as exist and, once tuned, can be used to predict properties that have not yet been observed. This is an ongoing process, in which models and results are refined as new data and interpretations become available and as understanding of the global system improves. Results of the research are described in several papers which were published or submitted for publication. These papers are summarized. Future research plans are presented.

Toward a mechanistic understanding of the damage evolution of SnAgCu solder joints in accelerated thermal cycling test

NASA Astrophysics Data System (ADS)

Mahin Shirazi, Sam

Accelerated thermal cycling (ATC) tests are the most commonly used tests for the thermo-mechanical performance assessment of microelectronics assemblies. Currently used reliability models have failed to incorporate the microstructural dependency of lead free solder joint behavior and its microstructure evolution during cycling. Thus, it is essential to have a mechanistic understanding of the effect of cycling parameters on damage evolution and failure of lead free solder joints in ATC. Recrystallization has been identified as the damage rate controlling mechanism in ATC. Usually it takes 1/3 of life for completion of recrystallization regardless of cycling parameters. Thus, the life of the solder joints can be predicted by estimating global recrystallization. The objective of the first part of the study was to examine whether the damage scenario applies in service is the same as the harsh thermal cycling tests (i.e. 0/100 °C and -40/125 °C) commonly used in industry. Microstructure analysis results on a variety of lead free solder SnAgCu assemblies subjected to the both harsh (0/100 °C) and mild (20/80 °C) ATC confirmed similar failure mechanism under the both testing conditions. Sn grain morphology (interlaced versus beach ball) has a significant effect on the thermo-mechanical performance (and thus the model) of the lead free solder joints. The longer thermal cycling lifetime observed in the interlaced solder joints subjected to the ATC compared to the beach ball structure was correlated to the different initial microstructure and the microstructure evolution during cycling. For the modeling proposes, the present study was focused on Sn-Ag-Cu solder joints with either a single Sn grain or beach ball structure. Microstructural analysis results of the simulated thermal cycling experiment revealed that, the life can be approximated as determined by the accumulation of a certain amount of work during the high temperature dwells. Finally the effect of precipitates spacing on acceleration factor was investigated. Results indicated that a smaller initial precipitate spacing would tend to result in a longer life in mild thermal cycling/service (where there is lower stresses). Accordingly, it is essential to incorporate the dependence of damage rate (i.e. recrystallization) on precipitate coarsening in any predictions.

Analysis of the economics of photovoltaic-diesel-battery energy systems for remote applications

NASA Technical Reports Server (NTRS)

Brainard, W. A.

1983-01-01

Computer simulations were conducted to analyze the performance and operating cost of a photovoltaic energy source combined with a diesel generator system and battery storage. The simulations were based on the load demand profiles used for the design of an all photovoltaic energy system installed in the remote Papago Indian Village of Schuchuli, Arizona. Twenty year simulations were run using solar insolation data from Phoenix SOLMET tapes. Total energy produced, energy consumed, operation and maintenance costs were calculated. The life cycle and levelized energy costs were determined for a variety of system configurations (i.e., varying amounts of photovoltaic array and battery storage).

Lithium Ion Testing at NSWC Crane in Support of NASA Goddard Space Flight Center

NASA Technical Reports Server (NTRS)

Brown, Harry; Jung, David; Lee, Leonine

2010-01-01

This viewgraph presentation reviews Lithium Ion Cell testing at the Naval Surface Warfare Center in Crane, India. The contents include: 1) Quallion 15 Ahr Lithium-Ion Cells, LEO Life Cycle Test; 2) Lithion 50 Ahr Lithium-Ion Cells, LEO Life Cycle Test; 3) ABSL 5 Ahr Lithium-Ion Battery, LRO-LLO Life Cycle Test, SDO-GEO Life Cycle Test; and 4) A123 40 Ahr Lithium-Ion Battery, GPM Life Cycle Test, MMS Life Cycle Test.

Concepts associated with a unified life cycle analysis

DOE Office of Scientific and Technical Information (OSTI.GOV)

Whelan, Gene; Peffers, Melissa S.; Tolle, Duane A.

There is a risk associated with most things in the world, and all things have a life cycle unto themselves, even brownfields. Many components can be described by a''cycle of life.'' For example, five such components are life-form, chemical, process, activity, and idea, although many more may exist. Brownfields may touch upon several of these life cycles. Each life cycle can be represented as independent software; therefore, a software technology structure is being formulated to allow for the seamless linkage of software products, representing various life-cycle aspects. Because classes of these life cycles tend to be independent of each other,more » the current research programs and efforts do not have to be revamped; therefore, this unified life-cycle paradigm builds upon current technology and is backward compatible while embracing future technology. Only when two of these life cycles coincide and one impacts the other is there connectivity and a transfer of information at the interface. The current framework approaches (e.g., FRAMES, 3MRA, etc.) have a design that is amenable to capturing (1) many of these underlying philosophical concepts to assure backward compatibility of diverse independent assessment frameworks and (2) linkage communication to help transfer the needed information at the points of intersection. The key effort will be to identify (1) linkage points (i.e., portals) between life cycles, (2) the type and form of data passing between life cycles, and (3) conditions when life cycles interact and communicate. This paper discusses design aspects associated with a unified life-cycle analysis, which can support not only brownfields but also other types of assessments.« less

NREL: U.S. Life Cycle Inventory Database Home Page

Science.gov Websites

U.S. Life-Cycle Inventory Database Buildings Research Photo of a green field with an ocean in the background. U.S. Life Cycle Inventory Database NREL and its partners created the U.S. Life Cycle Inventory (LCI) Database to help life cycle assessment (LCA) practitioners answer questions about environmental

NREL: U.S. Life Cycle Inventory Database - User Poll

Science.gov Websites

User Poll In preparation for the 2009 U.S. Life Cycle Inventory (LCI) Data Stakeholder meeting, the interested in life cycle analysis. The results from that poll and information gathered from the stakeholders polling data and feedback from life cycle analysis supporters helped develop the U.S. Life Cycle Inventory

Simulation and evaluation of latent heat thermal energy storage

NASA Technical Reports Server (NTRS)

Sigmon, T. W.

1980-01-01

The relative value of thermal energy storage (TES) for heat pump storage (heating and cooling) as a function of storage temperature, mode of storage (hotside or coldside), geographic locations, and utility time of use rate structures were derived. Computer models used to simulate the performance of a number of TES/heat pump configurations are described. The models are based on existing performance data of heat pump components, available building thermal load computational procedures, and generalized TES subsystem design. Life cycle costs computed for each site, configuration, and rate structure are discussed.

Equipment for testing automotive lead/acid batteries under SAE J240a conditions

NASA Astrophysics Data System (ADS)

Hamilton, J. A.; Rand, D. A. J.

Battery cycling equipment has been designed and constructed to test lead/acid batteries according to the American Society of Automotive Engineers' (SAE) J240a Standard. This life test simulates automotive service where the battery operates in a voltage-regulated charging system. The CSIRO design uses a master/slave concept to reduce both construction time and cost.

Costs and energy efficiency of a dual-mode system

NASA Technical Reports Server (NTRS)

Heft, R. C.

1977-01-01

The life cycle costs of a dual mode system for both public and semiprivate ownership are examined, and the costs in terms of levelized required revenue per passenger mile are presented. The energy use of the dual mode vehicle is analyzed by means of a detailed vehicle simulation program for the control policy and guideway system. Several different propulsion systems are considered.

A Classroom Exercise to Examine the Trade-off between Mission Capacity and Life Cycle Cost

ERIC Educational Resources Information Center

Kang, Keebom; Doerr, Kenneth H.

2015-01-01

This article presents a classroom exercise, centered on a simulation that has been used for 4 years in an MBA program to help students develop an understanding of the trade-offs involved in managing capital assets in the public sector. Though often ignored in business schools, "mission" is a key criterion that must be considered when…

Evaluating Data Clustering Approach for Life-Cycle Facility Control

DTIC Science & Technology

2013-04-01

produce 90% matching accuracy with noise/variations up to 55%. KEYWORDS: Building Information Modelling ( BIM ), machine learning, pattern detection...reconciled to building information model elements and ultimately to an expected resource utilization schedule. The motivation for this integration is to...by interoperable data sources and building information models . Building performance modelling and simulation efforts such as those by Maile et al

Capturing remote mixing due to internal tides using multi-scale modeling tool: SOMAR-LES

NASA Astrophysics Data System (ADS)

Santilli, Edward; Chalamalla, Vamsi; Scotti, Alberto; Sarkar, Sutanu

2016-11-01

Internal tides that are generated during the interaction of an oscillating barotropic tide with the bottom bathymetry dissipate only a fraction of their energy near the generation region. The rest is radiated away in the form of low- high-mode internal tides. These internal tides dissipate energy at remote locations when they interact with the upper ocean pycnocline, continental slope, and large scale eddies. Capturing the wide range of length and time scales involved during the life-cycle of internal tides is computationally very expensive. A recently developed multi-scale modeling tool called SOMAR-LES combines the adaptive grid refinement features of SOMAR with the turbulence modeling features of a Large Eddy Simulation (LES) to capture multi-scale processes at a reduced computational cost. Numerical simulations of internal tide generation at idealized bottom bathymetries are performed to demonstrate this multi-scale modeling technique. Although each of the remote mixing phenomena have been considered independently in previous studies, this work aims to capture remote mixing processes during the life cycle of an internal tide in more realistic settings, by allowing multi-level (coarse and fine) grids to co-exist and exchange information during the time stepping process.

10 CFR 436.19 - Life cycle costs.

Code of Federal Regulations, 2014 CFR

2014-01-01

... 10 Energy 3 2014-01-01 2014-01-01 false Life cycle costs. 436.19 Section 436.19 Energy DEPARTMENT... Procedures for Life Cycle Cost Analyses § 436.19 Life cycle costs. Life cycle costs are the sum of the... (d) Energy and/or water costs. [55 FR 48220, Nov. 20, 1990, as amended at 61 FR 32651, June 25, 1996] ...

10 CFR 436.19 - Life cycle costs.

Code of Federal Regulations, 2013 CFR

2013-01-01

... 10 Energy 3 2013-01-01 2013-01-01 false Life cycle costs. 436.19 Section 436.19 Energy DEPARTMENT... Procedures for Life Cycle Cost Analyses § 436.19 Life cycle costs. Life cycle costs are the sum of the... (d) Energy and/or water costs. [55 FR 48220, Nov. 20, 1990, as amended at 61 FR 32651, June 25, 1996] ...

10 CFR 436.19 - Life cycle costs.

Code of Federal Regulations, 2012 CFR

2012-01-01

... 10 Energy 3 2012-01-01 2012-01-01 false Life cycle costs. 436.19 Section 436.19 Energy DEPARTMENT... Procedures for Life Cycle Cost Analyses § 436.19 Life cycle costs. Life cycle costs are the sum of the... (d) Energy and/or water costs. [55 FR 48220, Nov. 20, 1990, as amended at 61 FR 32651, June 25, 1996] ...

Environmental characteristics comparison of Li-ion batteries and Ni-MH batteries under the uncertainty of cycle performance.

PubMed

Yu, Yajuan; Wang, Xiang; Wang, Dong; Huang, Kai; Wang, Lijing; Bao, Liying; Wu, Feng

2012-08-30

An environmental impact assessment model for secondary batteries under uncertainty is proposed, which is a combination of the life cycle assessment (LCA), Eco-indicator 99 system and Monte Carlo simulation (MCS). The LCA can describe the environmental impact mechanism of secondary batteries, whereas the cycle performance was simulated through MCS. The composite LCA-MCS model was then carried out to estimate the environmental impact of two kinds of experimental batteries. Under this kind of standard assessment system, a comparison between different batteries could be accomplished. The following results were found: (1) among the two selected batteries, the environmental impact of the Li-ion battery is lower than the nickel-metal hydride (Ni-MH) battery, especially with regards to resource consumption and (2) the lithium ion (Li-ion) battery is less sensitive to cycle uncertainty, its environmental impact fluctuations are small when compared with the selected Ni-MH battery and it is more environmentally friendly. The assessment methodology and model proposed in this paper can also be used for any other secondary batteries and they can be helpful in the development of environmentally friendly secondary batteries. Crown Copyright © 2012. Published by Elsevier B.V. All rights reserved.

Agent-Based Simulations of Malaria Transmissions with Applications to a Study Site in Thailand

NASA Technical Reports Server (NTRS)

Kiang, Richard K.; Adimi, Farida; Zollner, Gabriela E.; Coleman, Russell E.

2006-01-01

The dynamics of malaria transmission are driven by environmental, biotic and socioeconomic factors. Because of the geographic dependency of these factors and the complex interactions among them, it is difficult to generalize the key factors that perpetuate or intensify malaria transmission. Methods: Discrete event simulations were used for modeling the detailed interactions among the vector life cycle, sporogonic cycle and human infection cycle, under the explicit influences of selected extrinsic and intrinsic factors. Meteorological and environmental parameters may be derived from satellite data. The output of the model includes the individual infection status and the quantities normally observed in field studies, such as mosquito biting rates, sporozoite infection rates, gametocyte prevalence and incidence. Results were compared with mosquito vector and human malaria data acquired over 4.5 years (June 1999 - January 2004) in Kong Mong Tha, a remote village in Kanchanaburi Province, western Thailand. Results: Three years of transmissions of vivax and falciparum malaria were simulated for a hypothetical hamlet with approximately 1/7 of the study site population. The model generated results for a number of scenarios, including applications of larvicide and insecticide, asymptomatic cases receiving or not receiving treatment, blocking malaria transmission in mosquito vectors, and increasing the density of farm (host) animals in the hamlet. Transmission characteristics and trends in the simulated results are comparable to actual data collected at the study site.

10 CFR 435.8 - Life-cycle costing.

Code of Federal Regulations, 2013 CFR

2013-01-01

... 10 Energy 3 2013-01-01 2013-01-01 false Life-cycle costing. 435.8 Section 435.8 Energy DEPARTMENT...-cycle costing. Each Federal agency shall determine life-cycle cost-effectiveness by using the procedures..., including lower life-cycle costs, positive net savings, savings-to-investment ratio that is estimated to be...

10 CFR 435.8 - Life-cycle costing.

Code of Federal Regulations, 2014 CFR

2014-01-01

... 10 Energy 3 2014-01-01 2014-01-01 false Life-cycle costing. 435.8 Section 435.8 Energy DEPARTMENT...-cycle costing. Each Federal agency shall determine life-cycle cost-effectiveness by using the procedures..., including lower life-cycle costs, positive net savings, savings-to-investment ratio that is estimated to be...

10 CFR 435.8 - Life-cycle costing.

Code of Federal Regulations, 2012 CFR

2012-01-01

... 10 Energy 3 2012-01-01 2012-01-01 false Life-cycle costing. 435.8 Section 435.8 Energy DEPARTMENT...-cycle costing. Each Federal agency shall determine life-cycle cost-effectiveness by using the procedures..., including lower life-cycle costs, positive net savings, savings-to-investment ratio that is estimated to be...

A comparison of production system life cycle models

NASA Astrophysics Data System (ADS)

Attri, Rajesh; Grover, Sandeep

2012-09-01

Companies today need to keep up with the rapidly changing market conditions to stay competitive. The main issues in this paper are related to a company's market and its competitors. The prediction of market behavior is helpful for a manufacturing enterprise to build efficient production systems. However, these predictions are usually not reliable. A production system is required to adapt to changing markets, but such requirement entails higher cost. Hence, analyzing different life cycle models of the production system is necessary. In this paper, different life cycle models of the production system are compared to evaluate the distinctive features and the limitations of each model. Furthermore, the difference between product life cycle and production life cycle is summarized, and the effect of product life cycle on production life cycle is explained. Finally, a production system life cycle model, along with key activities to be performed in each stage, is proposed specifically for the manufacturing sector.

A life cycle database for parasitic acanthocephalans, cestodes, and nematodes

USGS Publications Warehouse

Benesh, Daniel P.; Lafferty, Kevin D.; Kuris, Armand

2017-01-01

Parasitologists have worked out many complex life cycles over the last ~150 years, yet there have been few efforts to synthesize this information to facilitate comparisons among taxa. Most existing host-parasite databases focus on particular host taxa, do not distinguish final from intermediate hosts, and lack parasite life-history information. We summarized the known life cycles of trophically transmitted parasitic acanthocephalans, cestodes, and nematodes. For 973 parasite species, we gathered information from the literature on the hosts infected at each stage of the parasite life cycle (8510 host-parasite species associations), what parasite stage is in each host, and whether parasites need to infect certain hosts to complete the life cycle. We also collected life-history data for these parasites at each life cycle stage, including 2313 development time measurements and 7660 body size measurements. The result is the most comprehensive data summary available for these parasite taxa. In addition to identifying gaps in our knowledge of parasite life cycles, these data can be used to test hypotheses about life cycle evolution, host specificity, parasite life-history strategies, and the roles of parasites in food webs.

Chasing Perfection: Should We Reduce Model Uncertainty in Carbon Cycle-Climate Feedbacks

NASA Astrophysics Data System (ADS)

Bonan, G. B.; Lombardozzi, D.; Wieder, W. R.; Lindsay, K. T.; Thomas, R. Q.

2015-12-01

Earth system model simulations of the terrestrial carbon (C) cycle show large multi-model spread in the carbon-concentration and carbon-climate feedback parameters. Large differences among models are also seen in their simulation of global vegetation and soil C stocks and other aspects of the C cycle, prompting concern about model uncertainty and our ability to faithfully represent fundamental aspects of the terrestrial C cycle in Earth system models. Benchmarking analyses that compare model simulations with common datasets have been proposed as a means to assess model fidelity with observations, and various model-data fusion techniques have been used to reduce model biases. While such efforts will reduce multi-model spread, they may not help reduce uncertainty (and increase confidence) in projections of the C cycle over the twenty-first century. Many ecological and biogeochemical processes represented in Earth system models are poorly understood at both the site scale and across large regions, where biotic and edaphic heterogeneity are important. Our experience with the Community Land Model (CLM) suggests that large uncertainty in the terrestrial C cycle and its feedback with climate change is an inherent property of biological systems. The challenge of representing life in Earth system models, with the rich diversity of lifeforms and complexity of biological systems, may necessitate a multitude of modeling approaches to capture the range of possible outcomes. Such models should encompass a range of plausible model structures. We distinguish between model parameter uncertainty and model structural uncertainty. Focusing on improved parameter estimates may, in fact, limit progress in assessing model structural uncertainty associated with realistically representing biological processes. Moreover, higher confidence may be achieved through better process representation, but this does not necessarily reduce uncertainty.

Impact of Life-Cycle Stage and Gender on the Ability to Balance Work and Family Responsibilities.

ERIC Educational Resources Information Center

Higgins, Christopher; And Others

1994-01-01

Examined impact of gender and life-cycle stage on three components of work-family conflict using sample of 3,616 respondents. For men, levels of work-family conflict were moderately lower in each successive life-cycle stage. For women, levels were similar in two early life-cycle stages but were significantly lower in later life-cycle stage.…

Updated estimation of energy efficiencies of U.S. petroleum refineries.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Palou-Rivera, I.; Wang, M. Q.

2010-12-08

Evaluation of life-cycle (or well-to-wheels, WTW) energy and emission impacts of vehicle/fuel systems requires energy use (or energy efficiencies) of energy processing or conversion activities. In most such studies, petroleum fuels are included. Thus, determination of energy efficiencies of petroleum refineries becomes a necessary step for life-cycle analyses of vehicle/fuel systems. Petroleum refinery energy efficiencies can then be used to determine the total amount of process energy use for refinery operation. Furthermore, since refineries produce multiple products, allocation of energy use and emissions associated with petroleum refineries to various petroleum products is needed for WTW analysis of individual fuels suchmore » as gasoline and diesel. In particular, GREET, the life-cycle model developed at Argonne National Laboratory with DOE sponsorship, compares energy use and emissions of various transportation fuels including gasoline and diesel. Energy use in petroleum refineries is key components of well-to-pump (WTP) energy use and emissions of gasoline and diesel. In GREET, petroleum refinery overall energy efficiencies are used to determine petroleum product specific energy efficiencies. Argonne has developed petroleum refining efficiencies from LP simulations of petroleum refineries and EIA survey data of petroleum refineries up to 2006 (see Wang, 2008). This memo documents Argonne's most recent update of petroleum refining efficiencies.« less

Estimates of Embodied Global Energy and Air-Emission Intensities of Japanese Products for Building a Japanese Input–Output Life Cycle Assessment Database with a Global System Boundary

PubMed Central

2012-01-01

To build a life cycle assessment (LCA) database of Japanese products embracing their global supply chains in a manner requiring lower time and labor burdens, this study estimates the intensity of embodied global environmental burden for commodities produced in Japan. The intensity of embodied global environmental burden is a measure of the environmental burden generated globally by unit production of the commodity and can be used as life cycle inventory data in LCA. The calculation employs an input–output LCA method with a global link input–output model that defines a global system boundary grounded in a simplified multiregional input–output framework. As results, the intensities of embodied global environmental burden for 406 Japanese commodities are determined in terms of energy consumption, greenhouse-gas emissions (carbon dioxide, methane, nitrous oxide, perfluorocarbons, hydrofluorocarbons, sulfur hexafluoride, and their summation), and air-pollutant emissions (nitrogen oxide and sulfur oxide). The uncertainties in the intensities of embodied global environmental burden attributable to the simplified structure of the global link input–output model are quantified using Monte Carlo simulation. In addition, by analyzing the structure of the embodied global greenhouse-gas intensities we characterize Japanese commodities in the context of LCA embracing global supply chains. PMID:22881452

Slocum-TREC Thermal Glider

NASA Technical Reports Server (NTRS)

Huntsberger, Terry; Jones, Jack A.; Valdez, Thomas; Stirbl, Rob

2012-01-01

JPL is now teaming with Teledyne-Webb-Research to produce the first thermal glider that uses PCM for direct buoyancy control (not electronic pumps) and to produce all other required electricity. TWR has increased electrical production total efficiency from 0.45 to 0.61. JPL performed over 6000 cycles (2.4 years) of accelerated life testing of a piston accumulator. Design, fabrication, and testing will be performed in 2012, with deployment by Rutgers University in late 2012. The proposed goal of the ocean endurance tests was 3 months, but will be extended to at last 1 year. The piston accumulator was cycled over 6,000 times in a three-month period in order to simulate continuous glider life of about 2.4 years, The life test data suggests that we might accumulate roughly 0.5 cc of gas in the oil bladders for each cycle. PCM canisters will be fabricated with a compressed aluminum foam core, 7.5% foam selected (< 42 minutes to freeze anticipated) An Axi 5345/18 3-Phase AC alternator selected for power generation, 61% energy storage efficiency A 4-Cell A123 Energy Storage Systems battery selected for energy storage, buss voltage 14.4 to 12.5 V (13.2 V nominal) Glider deployment expected in late 2012

Novel population genetics in ciliates due to life cycle and nuclear dimorphism.

PubMed

Morgens, David W; Stutz, Timothy C; Cavalcanti, Andre R O

2014-08-01

Our understanding of population genetics comes primarily from studies of organisms with canonical life cycles and nuclear organization, either haploid or diploid, sexual, or asexual. Although this template yields satisfactory results for the study of animals and plants, the wide variety of genomic organizations and life cycles of unicellular eukaryotes can make these organisms behave differently in response to mutation, selection, and drift than predicted by traditional population genetic models. In this study, we show how each of these unique features of ciliates affects their evolutionary parameters in mutation-selection, selection-drift, and mutation-selection-drift situations. In general, ciliates are less efficient in eliminating deleterious mutations-these mutations linger longer and at higher frequencies in ciliate populations than in sexual populations--and more efficient in selecting beneficial mutations. Approaching this problem via analytical techniques and simulation allows us to make specific predictions about the nature of ciliate evolution, and we discuss the implications of these results with respect to the high levels of polymorphism and high rate of protein evolution reported for ciliates. © The Author 2014. Published by Oxford University Press on behalf of the Society for Molecular Biology and Evolution. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Multiscale molecular dynamics simulation approaches to the structure and dynamics of viruses.

PubMed

Huber, Roland G; Marzinek, Jan K; Holdbrook, Daniel A; Bond, Peter J

2017-09-01

Viral pathogens are a significant source of human morbidity and mortality, and have a major impact on societies and economies around the world. One of the challenges inherent in targeting these pathogens with drugs is the tight integration of the viral life cycle with the host's cellular machinery. However, the reliance of the virus on the host cell replication machinery is also an opportunity for therapeutic targeting, as successful entry- and exit-inhibitors have demonstrated. An understanding of the extracellular and intracellular structure and dynamics of the virion - as well as of the entry and exit pathways in host and vector cells - is therefore crucial to the advancement of novel antivirals. In recent years, advances in computing architecture and algorithms have begun to allow us to use simulations to study the structure and dynamics of viral ultrastructures at various stages of their life cycle in atomistic or near-atomistic detail. In this review, we outline specific challenges and solutions that have emerged to allow for structurally detailed modelling of viruses in silico. We focus on the history and state of the art of atomistic and coarse-grained approaches to simulate the dynamics of the large, macromolecular structures associated with viral infection, and on their usefulness in explaining and expanding upon experimental data. We discuss the types of interactions that need to be modeled to describe major components of the virus particle and advances in modelling techniques that allow for the treatment of these systems, highlighting recent key simulation studies. Copyright © 2016 Elsevier Ltd. All rights reserved.

The life cycle of starbursting circumnuclear gas discs

NASA Astrophysics Data System (ADS)

Schartmann, M.; Mould, J.; Wada, K.; Burkert, A.; Durré, M.; Behrendt, M.; Davies, R. I.; Burtscher, L.

2018-01-01

High-resolution observations from the submm to the optical wavelength regime resolve the central few 100 pc region of nearby galaxies in great detail. They reveal a large diversity of features: thick gas and stellar discs, nuclear starbursts, inflows and outflows, central activity, jet interaction, etc. Concentrating on the role circumnuclear discs play in the life cycles of galactic nuclei, we employ 3D adaptive mesh refinement hydrodynamical simulations with the RAMSES code to self-consistently trace the evolution from a quasi-stable gas disc, undergoing gravitational (Toomre) instability, the formation of clumps and stars and the disc's subsequent, partial dispersal via stellar feedback. Our approach builds upon the observational finding that many nearby Seyfert galaxies have undergone intense nuclear starbursts in their recent past and in many nearby sources star formation is concentrated in a handful of clumps on a few 100 pc distant from the galactic centre. We show that such observations can be understood as the result of gravitational instabilities in dense circumnuclear discs. By comparing these simulations to available integral field unit observations of a sample of nearby galactic nuclei, we find consistent gas and stellar masses, kinematics, star formation and outflow properties. Important ingredients in the simulations are the self-consistent treatment of star formation and the dynamical evolution of the stellar distribution as well as the modelling of a delay time distribution for the supernova feedback. The knowledge of the resulting simulated density structure and kinematics on pc scale is vital for understanding inflow and feedback processes towards galactic scales.

Geographic variation and evolution in the life cycle of the witch-hazel leaf gall aphid, Hormaphis hamamelidis.

PubMed

von Dohlen, C D; Gill, D E

1989-02-01

Two divergent life cycles associated with different elevations and latitudes have been documented for the witch-hazel leaf gall aphid, Hormaphis hamamelidis. At low elevation in northern Virginia, the aphid had seven distinct generations alternating between the primary host, witchhazel (Hamamelis virginiana), and a secondary host, river birch (Betula nigra). These findings confirm the original published life cycle description for the same locality. A second, abbreviated life cycle consisting of only three generations restricted to witch-hazel was discovered at high elevation (1000 m) in north central and northwestern Virginia. Aphids of both life cycles were sympatric at a middle elevation site. The life cycles and morphology suggest that the two forms are separate species. Although monoecious life cycles on primary hosts in aphids generally are thought to be ancestral to complex host-alternating ones, it is certainly possible that monoecious cycles are sometimes secondarily derived from complex cycles. By constructing a preliminary phylogeny of the described species in the tribe Hormaphidini, we propose that the abbreviated life cycle is derived from the complex one in the case of these witchhazel gall aphids. Our findings are discussed in the context of current theory regarding the evolutionary stability of complex life cycles.

Fuel economy and life-cycle cost analysis of a fuel cell hybrid vehicle

NASA Astrophysics Data System (ADS)

Jeong, Kwi Seong; Oh, Byeong Soo

The most promising vehicle engine that can overcome the problem of present internal combustion is the hydrogen fuel cell. Fuel cells are devices that change chemical energy directly into electrical energy without combustion. Pure fuel cell vehicles and fuel cell hybrid vehicles (i.e. a combination of fuel cell and battery) as energy sources are studied. Considerations of efficiency, fuel economy, and the characteristics of power output in hybridization of fuel cell vehicle are necessary. In the case of Federal Urban Driving Schedule (FUDS) cycle simulation, hybridization is more efficient than a pure fuel cell vehicle. The reason is that it is possible to capture regenerative braking energy and to operate the fuel cell system within a more efficient range by using battery. Life-cycle cost is largely affected by the fuel cell size, fuel cell cost, and hydrogen cost. When the cost of fuel cell is high, hybridization is profitable, but when the cost of fuel cell is less than 400 US$/kW, a pure fuel cell vehicle is more profitable.

32 CFR Appendix to Part 162 - Reporting Procedures

Code of Federal Regulations, 2014 CFR

2014-07-01

... generated. e. Projected Life-Cycle Savings. For each PIF project provide the estimated amount of savings the project is projected to earn over the project's economic life. f. Projected Life-Cycle Cost Avoidance. For... Projected Life-Cycle Savings. e. Total Projected Life-Cycle Cost Avoidance. 3. CSI. Each DoD Component that...

10 CFR 433.8 - Life-cycle costing.

Code of Federal Regulations, 2014 CFR

2014-01-01

... 10 Energy 3 2014-01-01 2014-01-01 false Life-cycle costing. 433.8 Section 433.8 Energy DEPARTMENT... HIGH-RISE RESIDENTIAL BUILDINGS § 433.8 Life-cycle costing. Each Federal agency shall determine life... choose to use any of four methods, including lower life-cycle costs, positive net savings, savings-to...

19 CFR 207.27 - Short life cycle products.

Code of Federal Regulations, 2013 CFR

2013-04-01

... 19 Customs Duties 3 2013-04-01 2013-04-01 false Short life cycle products. 207.27 Section 207.27... SUBSIDIZED EXPORTS TO THE UNITED STATES Final Determinations, Short Life Cycle Products § 207.27 Short life... short life cycle merchandise which has been the subject of two or more affirmative dumping...

10 CFR 433.8 - Life-cycle costing.

Code of Federal Regulations, 2012 CFR

2012-01-01

... 10 Energy 3 2012-01-01 2012-01-01 false Life-cycle costing. 433.8 Section 433.8 Energy DEPARTMENT... HIGH-RISE RESIDENTIAL BUILDINGS § 433.8 Life-cycle costing. Each Federal agency shall determine life... choose to use any of four methods, including lower life-cycle costs, positive net savings, savings-to...

19 CFR 207.27 - Short life cycle products.

Code of Federal Regulations, 2014 CFR

2014-04-01

... 19 Customs Duties 3 2014-04-01 2014-04-01 false Short life cycle products. 207.27 Section 207.27... SUBSIDIZED EXPORTS TO THE UNITED STATES Final Determinations, Short Life Cycle Products § 207.27 Short life... short life cycle merchandise which has been the subject of two or more affirmative dumping...

10 CFR 433.8 - Life-cycle costing.

Code of Federal Regulations, 2013 CFR

2013-01-01

... 10 Energy 3 2013-01-01 2013-01-01 false Life-cycle costing. 433.8 Section 433.8 Energy DEPARTMENT... HIGH-RISE RESIDENTIAL BUILDINGS § 433.8 Life-cycle costing. Each Federal agency shall determine life... choose to use any of four methods, including lower life-cycle costs, positive net savings, savings-to...

19 CFR 207.27 - Short life cycle products.

Code of Federal Regulations, 2012 CFR

2012-04-01

... 19 Customs Duties 3 2012-04-01 2012-04-01 false Short life cycle products. 207.27 Section 207.27... SUBSIDIZED EXPORTS TO THE UNITED STATES Final Determinations, Short Life Cycle Products § 207.27 Short life... short life cycle merchandise which has been the subject of two or more affirmative dumping...

19 CFR 207.27 - Short life cycle products.

Code of Federal Regulations, 2010 CFR

2010-04-01

... 19 Customs Duties 3 2010-04-01 2010-04-01 false Short life cycle products. 207.27 Section 207.27... SUBSIDIZED EXPORTS TO THE UNITED STATES Final Determinations, Short Life Cycle Products § 207.27 Short life... short life cycle merchandise which has been the subject of two or more affirmative dumping...

19 CFR 207.27 - Short life cycle products.

Code of Federal Regulations, 2011 CFR

2011-04-01

... 19 Customs Duties 3 2011-04-01 2011-04-01 false Short life cycle products. 207.27 Section 207.27... SUBSIDIZED EXPORTS TO THE UNITED STATES Final Determinations, Short Life Cycle Products § 207.27 Short life... short life cycle merchandise which has been the subject of two or more affirmative dumping...

Does It Have a Life Cycle?

ERIC Educational Resources Information Center

Keeley, Page

2010-01-01

If life continues from generation to generation, then all plants and animals must go through a life cycle, even though it may be different from organism to organism. Is this what students have "learned," or do they have their own private conceptions about life cycles? The formative assessment probe "Does It Have a Life Cycle?" reveals some…

Environmental assessment of biofuel pathways in Ile de France based on ecosystem modeling.

PubMed

Gabrielle, Benoît; Gagnaire, Nathalie; Massad, Raia Silvia; Dufossé, Karine; Bessou, Cécile

2014-01-01

The objective of the work reported here was to reduce the uncertainty on the greenhouse gas balances of biofuels using agro-ecosystem modeling at a high resolution over the Ile-de-France region in Northern France. The emissions simulated during the feedstock production stage were input to a life-cycle assessment of candidate biofuel pathways: bioethanol from wheat, sugar-beet and miscanthus, and biodiesel from oilseed rape. Compared to the widely-used methodology based on fixed emission factors, ecosystem modeling lead to 55-70% lower estimates for N2O emissions, emphasizing the importance of regional factors. The life-cycle GHG emissions of first-generation biofuels were 50-70% lower than fossil-based equivalents, and 85% lower for cellulosic ethanol. When including indirect land-use change effects, GHG savings became marginal for biodiesel and wheat ethanol, but were positive due to direct effects for cellulosic ethanol. Copyright © 2013 Elsevier Ltd. All rights reserved.

The Effect of a Non-Gaussian Random Loading on High-Cycle Fatigue of a Thermally Post-Buckled Structure

NASA Technical Reports Server (NTRS)

Rizzi, Stephen A.; Behnke, marlana N.; Przekop, Adam

2010-01-01

High-cycle fatigue of an elastic-plastic beam structure under the combined action of thermal and high-intensity non-Gaussian acoustic loadings is considered. Such loadings can be highly damaging when snap-through motion occurs between thermally post-buckled equilibria. The simulated non-Gaussian loadings investigated have a range of skewness and kurtosis typical of turbulent boundary layer pressure fluctuations in the vicinity of forward facing steps. Further, the duration and steadiness of high excursion peaks is comparable to that found in such turbulent boundary layer data. Response and fatigue life estimates are found to be insensitive to the loading distribution, with the minor exception of cases involving plastic deformation. In contrast, the fatigue life estimate was found to be highly affected by a different type of non-Gaussian loading having bursts of high excursion peaks.

Hybrid Modeling for Testing Intelligent Software for Lunar-Mars Closed Life Support

NASA Technical Reports Server (NTRS)

Malin, Jane T.; Nicholson, Leonard S. (Technical Monitor)

1999-01-01

Intelligent software is being developed for closed life support systems with biological components, for human exploration of the Moon and Mars. The intelligent software functions include planning/scheduling, reactive discrete control and sequencing, management of continuous control, and fault detection, diagnosis, and management of failures and errors. Four types of modeling information have been essential to system modeling and simulation to develop and test the software and to provide operational model-based what-if analyses: discrete component operational and failure modes; continuous dynamic performance within component modes, modeled qualitatively or quantitatively; configuration of flows and power among components in the system; and operations activities and scenarios. CONFIG, a multi-purpose discrete event simulation tool that integrates all four types of models for use throughout the engineering and operations life cycle, has been used to model components and systems involved in the production and transfer of oxygen and carbon dioxide in a plant-growth chamber and between that chamber and a habitation chamber with physicochemical systems for gas processing.

Application of Life Cycle Assessment on Electronic Waste Management: A Review.

PubMed

Xue, Mianqiang; Xu, Zhenming

2017-04-01

Electronic waste is a rich source of both valuable materials and toxic substances. Management of electronic waste is one of the biggest challenges of current worldwide concern. As an effective and prevailing environmental management tool, life cycle assessment can evaluate the environmental performance of electronic waste management activities. Quite a few scientific literatures reporting life cycle assessment of electronic waste management with significant outcomes have been recently published. This paper reviewed the trends, characteristics, research gaps, and challenges of these studies providing detailed information for practitioners involved in electronic waste management. The results showed that life cycle assessment studies were most carried out in Europe, followed by Asia and North America. The research subject of the studies mainly includes monitors, waste printed circuit boards, mobile phones, computers, printers, batteries, toys, dishwashers, and light-emitting diodes. CML was the most widely used life cycle impact assessment method in life cycle assessment studies on electronic waste management, followed by EI99. Furthermore, 40% of the reviewed studies combined with other environmental tools, including life cycle cost, material flow analysis, multi-criteria decision analysis, emergy analysis, and hazard assessment which came to more comprehensive conclusions from different aspects. The research gaps and challenges including uneven distribution of life cycle assessment studies, life cycle impact assessment methods selection, comparison of the results, and uncertainty of the life cycle assessment studies were examined. Although life cycle assessment of electronic waste management facing challenges, their results will play more and more important role in electronic waste management practices.

Application of Life Cycle Assessment on Electronic Waste Management: A Review

NASA Astrophysics Data System (ADS)

Xue, Mianqiang; Xu, Zhenming

2017-04-01

Electronic waste is a rich source of both valuable materials and toxic substances. Management of electronic waste is one of the biggest challenges of current worldwide concern. As an effective and prevailing environmental management tool, life cycle assessment can evaluate the environmental performance of electronic waste management activities. Quite a few scientific literatures reporting life cycle assessment of electronic waste management with significant outcomes have been recently published. This paper reviewed the trends, characteristics, research gaps, and challenges of these studies providing detailed information for practitioners involved in electronic waste management. The results showed that life cycle assessment studies were most carried out in Europe, followed by Asia and North America. The research subject of the studies mainly includes monitors, waste printed circuit boards, mobile phones, computers, printers, batteries, toys, dishwashers, and light-emitting diodes. CML was the most widely used life cycle impact assessment method in life cycle assessment studies on electronic waste management, followed by EI99. Furthermore, 40% of the reviewed studies combined with other environmental tools, including life cycle cost, material flow analysis, multi-criteria decision analysis, emergy analysis, and hazard assessment which came to more comprehensive conclusions from different aspects. The research gaps and challenges including uneven distribution of life cycle assessment studies, life cycle impact assessment methods selection, comparison of the results, and uncertainty of the life cycle assessment studies were examined. Although life cycle assessment of electronic waste management facing challenges, their results will play more and more important role in electronic waste management practices.

Transportation life cycle assessment (LCA) synthesis : life cycle assessment learning module series.

DOT National Transportation Integrated Search

2015-03-12

The Life Cycle Assessment Learning Module Series is a set of narrated, self-advancing slideshows on : various topics related to environmental life cycle assessment (LCA). This research project produced the first 27 of such modules, which : are freely...

Tracking and Control of Gas Turbine Engine Component Damage/Life

NASA Technical Reports Server (NTRS)

Jaw, Link C.; Wu, Dong N.; Bryg, David J.

2003-01-01

This paper describes damage mechanisms and the methods of controlling damages to extend the on-wing life of critical gas turbine engine components. Particularly, two types of damage mechanisms are discussed: creep/rupture and thermo-mechanical fatigue. To control these damages and extend the life of engine hot-section components, we have investigated two methodologies to be implemented as additional control logic for the on-board electronic control unit. This new logic, the life-extending control (LEC), interacts with the engine control and monitoring unit and modifies the fuel flow to reduce component damages in a flight mission. The LEC methodologies were demonstrated in a real-time, hardware-in-the-loop simulation. The results show that LEC is not only a new paradigm for engine control design, but also a promising technology for extending the service life of engine components, hence reducing the life cycle cost of the engine.

Reliability and Productivity Modeling for the Optimization of Separated Spacecraft Interferometers

NASA Technical Reports Server (NTRS)

Kenny, Sean (Technical Monitor); Wertz, Julie

2002-01-01

As technological systems grow in capability, they also grow in complexity. Due to this complexity, it is no longer possible for a designer to use engineering judgement to identify the components that have the largest impact on system life cycle metrics, such as reliability, productivity, cost, and cost effectiveness. One way of identifying these key components is to build quantitative models and analysis tools that can be used to aid the designer in making high level architecture decisions. Once these key components have been identified, two main approaches to improving a system using these components exist: add redundancy or improve the reliability of the component. In reality, the most effective approach to almost any system will be some combination of these two approaches, in varying orders of magnitude for each component. Therefore, this research tries to answer the question of how to divide funds, between adding redundancy and improving the reliability of components, to most cost effectively improve the life cycle metrics of a system. While this question is relevant to any complex system, this research focuses on one type of system in particular: Separate Spacecraft Interferometers (SSI). Quantitative models are developed to analyze the key life cycle metrics of different SSI system architectures. Next, tools are developed to compare a given set of architectures in terms of total performance, by coupling different life cycle metrics together into one performance metric. Optimization tools, such as simulated annealing and genetic algorithms, are then used to search the entire design space to find the "optimal" architecture design. Sensitivity analysis tools have been developed to determine how sensitive the results of these analyses are to uncertain user defined parameters. Finally, several possibilities for the future work that could be done in this area of research are presented.

Life-cycle assessment of corn-based butanol as a potential transportation fuel.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wu, M.; Wang, M.; Liu, J.

2007-12-31

Butanol produced from bio-sources (such as corn) could have attractive properties as a transportation fuel. Production of butanol through a fermentation process called acetone-butanol-ethanol (ABE) has been the focus of increasing research and development efforts. Advances in ABE process development in recent years have led to drastic increases in ABE productivity and yields, making butanol production worthy of evaluation for use in motor vehicles. Consequently, chemical/fuel industries have announced their intention to produce butanol from bio-based materials. The purpose of this study is to estimate the potential life-cycle energy and emission effects associated with using bio-butanol as a transportation fuel.more » The study employs a well-to-wheels analysis tool--the Greenhouse Gases, Regulated Emissions and Energy Use in Transportation (GREET) model developed at Argonne National Laboratory--and the Aspen Plus{reg_sign} model developed by AspenTech. The study describes the butanol production from corn, including grain processing, fermentation, gas stripping, distillation, and adsorption for products separation. The Aspen{reg_sign} results that we obtained for the corn-to-butanol production process provide the basis for GREET modeling to estimate life-cycle energy use and greenhouse gas emissions. The GREET model was expanded to simulate the bio-butanol life cycle, from agricultural chemical production to butanol use in motor vehicles. We then compared the results for bio-butanol with those of conventional gasoline. We also analyzed the bio-acetone that is coproduced with bio-butanol as an alternative to petroleum-based acetone. Our study shows that, while the use of corn-based butanol achieves energy benefits and reduces greenhouse gas emissions, the results are affected by the methods used to treat the acetone that is co-produced in butanol plants.« less

Evidence from molecular dynamics simulations of conformational preorganization in the ribonuclease H active site

PubMed Central

Stafford, Kate A.; Palmer III, Arthur G.

2014-01-01

Ribonuclease H1 (RNase H) enzymes are well-conserved endonucleases that are present in all domains of life and are particularly important in the life cycle of retroviruses as domains within reverse transcriptase. Despite extensive study, especially of the E. coli homolog, the interaction of the highly negatively charged active site with catalytically required magnesium ions remains poorly understood. In this work, we describe molecular dynamics simulations of the E. coli homolog in complex with magnesium ions, as well as simulations of other homologs in their apo states. Collectively, these results suggest that the active site is highly rigid in the apo state of all homologs studied and is conformationally preorganized to favor the binding of a magnesium ion. Notably, representatives of bacterial, eukaryotic, and retroviral RNases H all exhibit similar active-site rigidity, suggesting that this dynamic feature is only subtly modulated by amino acid sequence and is primarily imposed by the distinctive RNase H protein fold. PMID:25075292

LIFE CYCLE DESIGN FRAMEWORK AND DEMONSTRATION PROJECTS PROFILES OF AT&T AND ALLIED SIGNAL

EPA Science Inventory

Life cycle design seeks to minimize the environmental burden associated with a product life cycle from raw materials acquisition through manufacturing, use, and end-of-life management. ife cycle design emphasizes integrating environmental requirements into the earliest phases of ...

CONFIG: Integrated engineering of systems and their operation

NASA Technical Reports Server (NTRS)

Malin, Jane T.; Ryan, Dan; Fleming, Land

1994-01-01

This article discusses CONFIG 3, a prototype software tool that supports integrated conceptual design evaluation from early in the product life cycle, by supporting isolated or integrated modeling, simulation, and analysis of the function, structure, behavior, failures and operations of system designs. Integration and reuse of models is supported in an object-oriented environment providing capabilities for graph analysis and discrete event simulation. CONFIG supports integration among diverse modeling approaches (component view, configuration or flow path view, and procedure view) and diverse simulation and analysis approaches. CONFIG is designed to support integrated engineering in diverse design domains, including mechanical and electro-mechanical systems, distributed computer systems, and chemical processing and transport systems.

Next Generation CAD/CAM/CAE Systems

NASA Technical Reports Server (NTRS)

Noor, Ahmed K. (Compiler); Malone, John B. (Compiler)

1997-01-01

This document contains presentations from the joint UVA/NASA Workshop on Next Generation CAD/CAM/CAE Systems held at NASA Langley Research Center in Hampton, Virginia on March 18-19, 1997. The presentations focused on current capabilities and future directions of CAD/CAM/CAE systems, aerospace industry projects, and university activities related to simulation-based design. Workshop attendees represented NASA, commercial software developers, the aerospace industry, government labs, and academia. The workshop objectives were to assess the potential of emerging CAD/CAM/CAE technology for use in intelligent simulation-based design and to provide guidelines for focused future research leading to effective use of CAE systems for simulating the entire life cycle of aerospace systems.

Simulation of fatigue fracture of TiNi shape memory alloy samples at cyclic loading in pseudoelastic state

NASA Astrophysics Data System (ADS)

Belyaev, Fedor S.; Volkov, Aleksandr E.; Evard, Margarita E.; Khvorov, Aleksandr A.

2018-05-01

Microstructural simulation of mechanical behavior of shape memory alloy samples at cyclic loading in the pseudoelastic state has been carried out. Evolution of the oriented and scattered deformation defects leading to damage accumulation and resulting in the fatigue fracture has been taken into account. Simulations were performed for the regime of loading imitating that for endovascular stents: preliminary straining, unloading, deformation up to some mean level of the strain and subsequent mechanical cycling at specified strain amplitude. Dependence of the fatigue life on the loading parameters (pre-strain, mean and amplitude values of strain) has been obtained. The results show a good agreement with available experimental data.

Regenerative flywheel energy storage system. Volume 3: Life cycle and cost-benefit analysis of a battery-flywheel electric car

NASA Astrophysics Data System (ADS)

1980-06-01

Fabrication of the inductor motor, the flywheel, the power conditioner, and the system control is described. Test results of the system operating over the SAE j227a Schedule D driving cycle are given and are compared to the calculated value. The flywheel energy storage system consists of a solid rotor, synchronous, inductor-type, flywheel drive machine electrically coupled to a dc battery electric propulsion system through a load-commutated inverter. The motor/alernator unit is coupled mechanically to a small steel flywheel which provides a portion of the vehicle's accelerating energy and regenerates the vehicle's braking energy. Laboratory simulation of the electric vehicle propulsion system included a 108 volt, lead-acid battery bank and a separately excited dc propulsion motor coupled to a flywheel and generator which simulate the vehicle's inertia and losses.

Life cycles of dominant mayflies (Ephemeroptera) on a torrent of the high Bolivian Andes

PubMed

Molina, Carlos I; Puliafico, Kenneth P

2016-03-01

The mayflies of the temperate and cold zones have well-synchronized life cycles, distinct cohorts, short emergence and flight periods. In contrast, aquatic insects from the tropical zones are characterized by multivoltine life cycles, “non-discernible cohorts” and extended flight periods throughout the year. This report is the first observation of life cycle patterns made of two species of mayflies on a torrent in the high elevation Bolivian Andes. The samples were taken from four sites and four periods during a hydrological season. The life cycle of each species was examined using size-class frequency analysis and a monthly modal progression model (von Bertalanffy’s model) to infer the life cycle synchrony type. These first observations showed a moderately synchronized univoltine life cycle for Andesiops peruvianus (Ulmer, 1920), whereas Meridialaris tintinnabula Pescador and Peters (1987), had an unsynchronized multivoltine life cycle. These results showed that the generalization of all aquatic insects as unsynchronized multivoltine species in the Andean region may not be entirely accurate since there is still a need to further clarify the life cycle patterns of the wide variety of aquatic insects living in this high elevation tropical environment.

From Centralized Disassembly to Life Cycle Management: Status and Progress of E-waste Treatment System in China

NASA Astrophysics Data System (ADS)

Song, Xiaolong; Yang, Jianxin; Lu, Bin; Yang, Dong

2017-01-01

China is now facing e-waste problems from both growing domestic generation and illegal imports. Many stakeholders are involved in the e-waste treatment system due to the complexity of e-waste life cycle. Beginning with the state of the e-waste treatment industry in China, this paper summarizes the latest progress in e-waste management from such aspects as the new edition of the China RoHS Directive, new Treatment List, new funding subsidy standard, and eco-design pilots. Thus, a conceptual model for life cycle management of e-waste is generalized. The operating procedure is to first identify the life cycle stages of the e-waste and extract the important life cycle information. Then, life cycle tools can be used to conduct a systematic analysis to help decide how to maximize the benefits from a series of life cycle engineering processes. Meanwhile, life cycle thinking is applied to improve the legislation relating to e-waste so as to continuously improve the sustainability of the e-waste treatment system. By providing an integrative framework, the life cycle management of e-waste should help to realize sustainable management of e-waste in developing countries.

Exploring the Underlying Mechanisms of the Xenopus laevis Embryonic Cell Cycle.

PubMed

Zhang, Kun; Wang, Jin

2018-05-31

The cell cycle is an indispensable process in proliferation and development. Despite significant efforts, global quantification and physical understanding are still challenging. In this study, we explored the mechanisms of the Xenopus laevis embryonic cell cycle by quantifying the underlying landscape and flux. We uncovered the Mexican hat landscape of the Xenopus laevis embryonic cell cycle with several local basins and barriers on the oscillation path. The local basins characterize the different phases of the Xenopus laevis embryonic cell cycle, and the local barriers represent the checkpoints. The checkpoint mechanism of the cell cycle is revealed by the landscape basins and barriers. While landscape shape determines the stabilities of the states on the oscillation path, the curl flux force determines the stability of the cell cycle flow. Replication is fundamental for biology of living cells. We quantify the input energy (through the entropy production) as the thermodynamic requirement for initiation and sustainability of single cell life (cell cycle). Furthermore, we also quantify curl flux originated from the input energy as the dynamical requirement for the emergence of a new stable phase (cell cycle). This can provide a new quantitative insight for the origin of single cell life. In fact, the curl flux originated from the energy input or nutrition supply determines the speed and guarantees the progression of the cell cycle. The speed of the cell cycle is a hallmark of cancer. We characterized the quality of the cell cycle by the coherence time and found it is supported by the flux and energy cost. We are also able to quantify the degree of time irreversibility by the cross correlation function forward and backward in time from the stochastic traces in the simulation or experiments, providing a way for the quantification of the time irreversibility and the flux. Through global sensitivity analysis upon landscape and flux, we can identify the key elements for controlling the cell cycle speed. This can help to design an effective strategy for drug discovery against cancer.

LCIA framework and cross-cutting issues guidance within the UNEP/SETAC Life Cycle Initiative

EPA Science Inventory

Increasing needs for decision support and advances in scientific knowledge within life cycle assessment (LCA) led to substantial efforts to provide global guidance on environmental life cycle impact assessment (LCIA) indicators under the auspices of the UNEP-SETAC Life Cycle Init...

Is There a Tectonically Driven Supertidal Cycle?

NASA Astrophysics Data System (ADS)

Green, J. A. M.; Molloy, J. L.; Davies, H. S.; Duarte, J. C.

2018-04-01

Earth is 180 Myr into the current supercontinent cycle, and the next supercontinent is predicted to form in 250 Myr. The continuous changes in continental configuration can move the ocean between resonant states, and the semidiurnal tides are currently large compared to the past 252 Myr due to tidal resonance in the Atlantic. This leads to the hypothesis that there is a "supertidal" cycle linked to the supercontinent cycle. Here this is tested using new tectonic predictions for the next 250 Myr as bathymetry in a numerical tidal model. The simulations support the following hypothesis: a new tidal resonance will appear 150 Myr from now, followed by a decreasing tide as the supercontinent forms 100 Myr later. This affects the dissipation of tidal energy in the oceans, with consequences for the evolution of the Earth-Moon system, ocean circulation and climate, and implications for the ocean's capacity of hosting and evolving life.

Thermal stress cycling of GaAs solar cells

NASA Technical Reports Server (NTRS)

Janousek, B. K.; Francis, R. W.; Wendt, J. P.

1985-01-01

A thermal cycling experiment was performed on GaAs solar cells to establish the electrical and structural integrity of these cells under the temperature conditions of a simulated low-Earth orbit of 3-year duration. Thirty single junction GaAs cells were obtained and tests were performed to establish the beginning-of-life characteristics of these cells. The tests consisted of cell I-V power output curves, from which were obtained short-circuit current, open circuit voltage, fill factor, and cell efficiency, and optical micrographs, spectral response, and ion microprobe mass analysis (IMMA) depth profiles on both the front surfaces and the front metallic contacts of the cells. Following 5,000 thermal cycles, the performance of the cells was reexamined in addition to any factors which might contribute to performance degradation. It is established that, after 5,000 thermal cycles, the cells retain their power output with no loss of structural integrity or change in physical appearance.

Nitrogen and Oxygen Isotopic Studies of the Marine Nitrogen Cycle

NASA Astrophysics Data System (ADS)

Casciotti, Karen L.

2016-01-01

The marine nitrogen cycle is a complex web of microbially mediated reactions that control the inventory, distribution, and speciation of nitrogen in the marine environment. Because nitrogen is a major nutrient that is required by all life, its availability can control biological productivity and ecosystem structure in both surface and deep-ocean communities. Stable isotopes of nitrogen and oxygen in nitrate and nitrite have provided new insights into the rates and distributions of marine nitrogen cycle processes, especially when analyzed in combination with numerical simulations of ocean circulation and biogeochemistry. This review highlights the insights gained from dual-isotope studies applied at regional to global scales and their incorporation into oceanic biogeochemical models. These studies represent significant new advances in the use of isotopic measurements to understand the modern nitrogen cycle, with implications for the study of past ocean productivity, oxygenation, and nutrient status.

The Model Life-cycle: Training Module

EPA Pesticide Factsheets

Model Life-Cycle includes identification of problems & the subsequent development, evaluation, & application of the model. Objectives: define ‘model life-cycle’, explore stages of model life-cycle, & strategies for development, evaluation, & applications.

10 CFR 434.607 - Life cycle cost analysis criteria.

Code of Federal Regulations, 2011 CFR

2011-01-01

... 10 Energy 3 2011-01-01 2011-01-01 false Life cycle cost analysis criteria. 434.607 Section 434.607... HIGH RISE RESIDENTIAL BUILDINGS Building Energy Compliance Alternative § 434.607 Life cycle cost analysis criteria. 607.1 The following life cycle cost criteria applies to the fuel selection requirements...

77 FR 38766 - Proposed Information Collection; Comment Request; International Client Life-Cycle Multi-Purpose...

Federal Register 2010, 2011, 2012, 2013, 2014

2012-06-29

... Request; International Client Life-Cycle Multi-Purpose Forms AGENCY: International Trade Administration... aspects of an international organization's life-cycle with CS. CS is mandated by Congress to help U.S... trade events to U.S. organizations. The International Client Life-cycle Multi-Purpose Forms, previously...

10 CFR 435.8 - Life-cycle costing.

Code of Federal Regulations, 2011 CFR

2011-01-01

... 10 Energy 3 2011-01-01 2011-01-01 false Life-cycle costing. 435.8 Section 435.8 Energy DEPARTMENT... BUILDINGS Mandatory Energy Efficiency Standards for Federal Low-Rise Residential Buildings. § 435.8 Life-cycle costing. Each Federal agency shall determine life-cycle cost-effectiveness by using the procedures...

77 FR 38582 - Proposed Information Collection; Comment Request; Domestic Client Life-Cycle Multi-Purpose Forms

Federal Register 2010, 2011, 2012, 2013, 2014

2012-06-28

... Request; Domestic Client Life-Cycle Multi-Purpose Forms AGENCY: International Trade Administration. ACTION... life-cycle with CS. CS is mandated by Congress to help U.S. organizations, particularly small and... Client Life-cycle Multi-Purpose Forms, previously titled Export Information Services Order Forms, are...

10 CFR 434.607 - Life cycle cost analysis criteria.

Code of Federal Regulations, 2010 CFR

2010-01-01

... 10 Energy 3 2010-01-01 2010-01-01 false Life cycle cost analysis criteria. 434.607 Section 434.607... HIGH RISE RESIDENTIAL BUILDINGS Building Energy Compliance Alternative § 434.607 Life cycle cost analysis criteria. 607.1 The following life cycle cost criteria applies to the fuel selection requirements...

10 CFR 435.8 - Life-cycle costing.

Code of Federal Regulations, 2010 CFR

2010-01-01

... 10 Energy 3 2010-01-01 2010-01-01 false Life-cycle costing. 435.8 Section 435.8 Energy DEPARTMENT... BUILDINGS Mandatory Energy Efficiency Standards for Federal Low-Rise Residential Buildings. § 435.8 Life-cycle costing. Each Federal agency shall determine life-cycle cost-effectiveness by using the procedures...

US Federal LCA Commons Life Cycle Inventory Unit Process Template

EPA Science Inventory

The US Federal LCA Commons Life Cycle Inventory Unit Process Template is a multi-sheet Excel template for life cycle inventory data, metadata and other documentation. The template comes as a package that consistent of three parts: (1) the main template itself for life cycle inven...

76 FR 41525 - Hewlett Packard Global Parts Supply Chain, Global Product Life Cycles Management Unit Including...

Federal Register 2010, 2011, 2012, 2013, 2014

2011-07-14

... Parts Supply Chain, Global Product Life Cycles Management Unit Including Teleworkers Reporting to... workers of Hewlett Packard, Global Parts Supply Chain, Global Product Life Cycles Management Unit...). Since eligible workers of Hewlett Packard, Global Parts Supply Chain, Global Product Life Cycles...

7 CFR 2902.8 - Determining life cycle costs, environmental and health benefits, and performance.

Code of Federal Regulations, 2010 CFR

2010-01-01

... 7 Agriculture 15 2010-01-01 2010-01-01 false Determining life cycle costs, environmental and... DESIGNATING BIOBASED PRODUCTS FOR FEDERAL PROCUREMENT General § 2902.8 Determining life cycle costs, environmental and health benefits, and performance. (a) Providing information on life cycle costs and...

77 FR 50724 - Developing Software Life Cycle Processes for Digital Computer Software Used in Safety Systems of...

Federal Register 2010, 2011, 2012, 2013, 2014

2012-08-22

... NUCLEAR REGULATORY COMMISSION [NRC-2012-0195] Developing Software Life Cycle Processes for Digital... Software Life Cycle Processes for Digital Computer Software used in Safety Systems of Nuclear Power Plants... clarifications, the enhanced consensus practices for developing software life-cycle processes for digital...

How Many Batches Are Needed for Process Validation under the New FDA Guidance?

PubMed

Yang, Harry

2013-01-01

The newly updated FDA Guidance for Industry on Process Validation: General Principles and Practices ushers in a life cycle approach to process validation. While the guidance no longer considers the use of traditional three-batch validation appropriate, it does not prescribe the number of validation batches for a prospective validation protocol, nor does it provide specific methods to determine it. This potentially could leave manufacturers in a quandary. In this paper, I develop a Bayesian method to address the issue. By combining process knowledge gained from Stage 1 Process Design (PD) with expected outcomes of Stage 2 Process Performance Qualification (PPQ), the number of validation batches for PPQ is determined to provide a high level of assurance that the process will consistently produce future batches meeting quality standards. Several examples based on simulated data are presented to illustrate the use of the Bayesian method in helping manufacturers make risk-based decisions for Stage 2 PPQ, and they highlight the advantages of the method over traditional Frequentist approaches. The discussions in the paper lend support for a life cycle and risk-based approach to process validation recommended in the new FDA guidance. The newly updated FDA Guidance for Industry on Process Validation: General Principles and Practices ushers in a life cycle approach to process validation. While the guidance no longer considers the use of traditional three-batch validation appropriate, it does not prescribe the number of validation batches for a prospective validation protocol, nor does it provide specific methods to determine it. This potentially could leave manufacturers in a quandary. In this paper, I develop a Bayesian method to address the issue. By combining process knowledge gained from Stage 1 Process Design (PD) with expected outcomes of Stage 2 Process Performance Qualification (PPQ), the number of validation batches for PPQ is determined to provide a high level of assurance that the process will consistently produce future batches meeting quality standards. Several examples based on simulated data are presented to illustrate the use of the Bayesian method in helping manufacturers make risk-based decisions for Stage 2 PPQ, and THEY highlight the advantages of the method over traditional Frequentist approaches. The discussions in the paper lend support for a life cycle and risk-based approach to process validation recommended in the new FDA guidance.

Life cycle replacement by gene introduction under an allee effect in periodical cicadas.

PubMed

Nariai, Yukiko; Hayashi, Saki; Morita, Satoru; Umemura, Yoshitaka; Tainaka, Kei-ichi; Sota, Teiji; Cooley, John R; Yoshimura, Jin

2011-04-06

Periodical cicadas (Magicicada spp.) in the USA are divided into three species groups (-decim, -cassini, -decula) of similar but distinct morphology and behavior. Each group contains at least one species with a 17-year life cycle and one with a 13-year cycle; each species is most closely related to one with the other cycle. One explanation for the apparent polyphyly of 13- and 17-year life cycles is that populations switch between the two cycles. Using a numerical model, we test the general feasibility of life cycle switching by the introduction of alleles for one cycle into populations of the other cycle. Our results suggest that fitness reductions at low population densities of mating individuals (the Allee effect) could play a role in life cycle switching. In our model, if the 13-year cycle is genetically dominant, a 17-year cycle population will switch to a 13-year cycle given the introduction of a few 13-year cycle alleles under a moderate Allee effect. We also show that under a weak Allee effect, different year-classes ("broods") with 17-year life cycles can be generated. Remarkably, the outcomes of our models depend only on the dominance relationships of the cycle alleles, irrespective of any fitness advantages.

Payload maintenance cost model for the space telescope

NASA Technical Reports Server (NTRS)

White, W. L.

1980-01-01

An optimum maintenance cost model for the space telescope for a fifteen year mission cycle was developed. Various documents and subsequent updates of failure rates and configurations were made. The reliability of the space telescope for one year, two and one half years, and five years were determined using the failure rates and configurations. The failure rates and configurations were also used in the maintenance simulation computer model which simulate the failure patterns for the fifteen year mission life of the space telescope. Cost algorithms associated with the maintenance options as indicated by the failure patterns were developed and integrated into the model.

Towards improving software security by using simulation to inform requirements and conceptual design

DOE PAGES

Nutaro, James J.; Allgood, Glenn O.; Kuruganti, Teja

2015-06-17

We illustrate the use of modeling and simulation early in the system life-cycle to improve security and reduce costs. The models that we develop for this illustration are inspired by problems in reliability analysis and supervisory control, for which similar models are used to quantify failure probabilities and rates. In the context of security, we propose that models of this general type can be used to understand trades between risk and cost while writing system requirements and during conceptual design, and thereby significantly reduce the need for expensive security corrections after a system enters operation

Effect of KOH concentration on LEO cycle life of IPV nickel-hydrogen flight cells. An update

NASA Technical Reports Server (NTRS)

Smithrick, John J.; Hall, Stephen W.

1991-01-01

An update of validation test results confirming the breakthrough in LEO cycle life of nickel-hydrogen cells containing 26 percent potassium hydroxide (KOH) electrolyte is presented. A breakthrough in the LEO cycle life of individual pressure vessel nickel-hydrogen cells is reported. The cycle life of boiler plate cells containing 26 percent KOH electrolyte was about 40,000 LEO cycles compared to 3500 cycles for cells containing 31 percent KOH.

Effect of KOH concentration on LEO cycle life of IPV nickel-hydrogen flight cells - An update

NASA Technical Reports Server (NTRS)

Smithrick, John J.; Hall, Stephen W.

1991-01-01

An update of validation test results confirming the breakthrough in LEO cycle life of nickel-hydrogen cells containing 26 percent potassium hydroxide (KOH) electrolyte is presented. A breakthrough in the LEO cycle life of individual pressure vessel nickel-hydrogen cells is reported. The cycle life of boiler plate cells containing 26 percent KOH electrolyte was about 40,000 LEO cycles compared to 3500 cycles for cells containing 31 percent KOH.

Gimme shelter--the relative sensitivity of parasitic nematodes with direct and indirect life cycles to climate change.

PubMed

Molnár, Péter K; Dobson, Andrew P; Kutz, Susan J

2013-11-01

Climate change is expected to alter the dynamics of host-parasite systems globally. One key element in developing predictive models for these impacts is the life cycle of the parasite. It is, for example, commonly assumed that parasites with an indirect life cycle would be more sensitive to changing environmental conditions than parasites with a direct life cycle due to the greater chance that at least one of their obligate host species will go extinct. Here, we challenge this notion by contrasting parasitic nematodes with a direct life cycle against those with an indirect life cycle. Specifically, we suggest that behavioral thermoregulation by the intermediate host may buffer the larvae of indirectly transmitted parasites against temperature extremes, and hence climate warming. We term this the 'shelter effect'. Formalizing each life cycle in a comprehensive model reveals a fitness advantage for the direct life cycle over the indirect life cycle at low temperatures, but the shelter effect reverses this advantage at high temperatures. When examined for seasonal environments, the models suggest that climate warming may in some regions create a temporal niche in mid-summer that excludes parasites with a direct life cycle, but allows parasites with an indirect life cycle to persist. These patterns are amplified if parasite larvae are able to manipulate their intermediate host to increase ingestion probability by definite hosts. Furthermore, our results suggest that exploiting the benefits of host sheltering may have aided the evolution of indirect life cycles. Our modeling framework utilizes the Metabolic Theory of Ecology to synthesize the complexities of host behavioral thermoregulation and its impacts on various temperature-dependent parasite life history components in a single measure of fitness, R0 . It allows quantitative predictions of climate change impacts, and is easily generalized to many host-parasite systems. © 2013 John Wiley & Sons Ltd.

Long life monopropellant hydrazine thruster evaluation for Space Station Freedom application - Test results

NASA Technical Reports Server (NTRS)

Popp, Christopher G.; Cook, Joseph C.; Ragland, Brenda L.; Pate, Leah R.

1992-01-01

In support of propulsion system thruster development activity for Space Station Freedom (SSF), NASA Johnson Space Center (JSC) conducted a hydrazine thruster technology demonstration program. The goal of this program was to identify impulse life capability of state-of-the-art long life hydrazine thrusters nominally rated for 50 pounds thrust at 300 psia supply pressure. The SSF propulsion system requirement for impulse life of this thruster class is 1.5 million pounds-seconds, corresponding to a throughput of approximately 6400 pounds of propellant. Long life thrusters were procured from The Marquardt Company, Hamilton Standard, and Rocket Research Company, Testing at JSC was completed on the thruster designs to quantify life while simulating expected thruster firing duty cycles and durations for SSF. This paper presents a review of the SSF propulsion system hydrazine thruster requirements, summaries of the three long life thruster designs procured by JSC and acceptance test results for each thruster, the JSC thruster life evaluation test program, and the results of the JSC test program.

Cyclic Oxidation Behavior of Simulated Post-Weld Heat-Treated P91

NASA Astrophysics Data System (ADS)

Rajendran Pillai, S.; Dayal, R. K.

2011-10-01

For long-term service life it is desirable that the high-temperature components posses slow-growing oxide scale. The growth and degradation of the oxide scale on P91 were studied by a thermal cycling method. The oxidation temperature was 780 °C and the duration of each cycle was 2 h. The mass gain and integrity of the scale was examined using a thermogravimetric balance. Any lack of integrity is monitored by the transient mass gain associated with the exposure of fresh surface. The scale retained the integrity throughout 100 cycles. Post-oxidation examination was carried out by scanning electron microscopy, energy dispersive spectroscopy and laser Raman spectroscopy. The nature of the scale was characterized and the reason for the compositional segregation is analyzed.

Experimental and numerical investigation of strain rate effect on low cycle fatigue behaviour of AA 5754 alloy

NASA Astrophysics Data System (ADS)

Kumar, P.; Singh, A.

2018-04-01

The present study deals with evaluation of low cycle fatigue (LCF) behavior of aluminum alloy 5754 (AA 5754) at different strain rates. This alloy has magnesium (Mg) as main alloying element (Al-Mg alloy) which makes this alloy suitable for Marines and Cryogenics applications. The testing procedure and specimen preparation are guided by ASTM E606 standard. The tests are performed at 0.5% strain amplitude with three different strain rates i.e. 0.5×10-3 sec-1, 1×10-3 sec-1 and 2×10-3 sec-1 thus the frequency of tests vary accordingly. The experimental results show that there is significant decrease in the fatigue life with the increase in strain rate. LCF behavior of AA 5754 is also simulated at different strain rates by finite element method. Chaboche kinematic hardening cyclic plasticity model is used for simulating the hardening behavior of the material. Axisymmetric finite element model is created to reduce the computational cost of the simulation. The material coefficients used for “Chaboche Model” are determined by experimentally obtained stabilized hysteresis loop. The results obtained from finite element simulation are compared with those obtained through LCF experiments.

The Sphinx's Riddle: Life and Career Cycles.

ERIC Educational Resources Information Center

Burack, Elmer H.

1984-01-01

Career cycles should be considered apart from life cycles, even though the two are interrelated. This essay examines five theories about life and career cycles, and offers insights into their limitations and potential uses. (JB)

Life Cycle Assessment of Wall Systems

NASA Astrophysics Data System (ADS)

Ramachandran, Sriranjani

Natural resource depletion and environmental degradation are the stark realities of the times we live in. As awareness about these issues increases globally, industries and businesses are becoming interested in understanding and minimizing the ecological footprints of their activities. Evaluating the environmental impacts of products and processes has become a key issue, and the first step towards addressing and eventually curbing climate change. Additionally, companies are finding it beneficial and are interested in going beyond compliance using pollution prevention strategies and environmental management systems to improve their environmental performance. Life-cycle Assessment (LCA) is an evaluative method to assess the environmental impacts associated with a products' life-cycle from cradle-to-grave (i.e. from raw material extraction through to material processing, manufacturing, distribution, use, repair and maintenance, and finally, disposal or recycling). This study focuses on evaluating building envelopes on the basis of their life-cycle analysis. In order to facilitate this analysis, a small-scale office building, the University Services Building (USB), with a built-up area of 148,101 ft2 situated on ASU campus in Tempe, Arizona was studied. The building's exterior envelope is the highlight of this study. The current exterior envelope is made of tilt-up concrete construction, a type of construction in which the concrete elements are constructed horizontally and tilted up, after they are cured, using cranes and are braced until other structural elements are secured. This building envelope is compared to five other building envelope systems (i.e. concrete block, insulated concrete form, cast-in-place concrete, steel studs and curtain wall constructions) evaluating them on the basis of least environmental impact. The research methodology involved developing energy models, simulating them and generating changes in energy consumption due to the above mentioned envelope types. Energy consumption data, along with various other details, such as building floor area, areas of walls, columns, beams etc. and their material types were imported into Life-Cycle Assessment software called ATHENA impact estimator for buildings. Using this four-stepped LCA methodology, the results showed that the Steel Stud envelope performed the best and less environmental impact compared to other envelope types. This research methodology can be applied to other building typologies.

Nitrogen rate and landscape impacts on life cycle energy use and emissions from switchgrass-derived ethanol

DOE PAGES

Mbonimpa, Eric G.; Kumar, Sandeep; Owens, Vance N.; ...

2015-08-24

Switchgrass-derived ethanol has been proposed as an alternative to fossil fuels to improve sustainability of the US energy sector. In this study, life cycle analysis (LCA) was used to estimate the environmental benefits of this fuel. To better define the LCA environmental impacts associated with fertilization rates and farm-landscape topography, results from a controlled experiment were analyzed. Data from switchgrass plots planted in 2008, consistently managed with three nitrogen rates (0, 56, and 112 kg N ha –1), two landscape positions (shoulder and footslope), and harvested annually (starting in 2009, the year after planting) through 2014 were used as inputmore » into the Greenhouse gases, Regulated Emissions and Energy use in transportation (GREET) model. Simulations determined nitrogen (N) rate and landscape impacts on the life cycle energy and emissions from switchgrass ethanol used in a passenger car as ethanol–gasoline blends (10% ethanol:E10, 85% ethanol:E85s). Results indicated that E85s may lead to lower fossil fuels use (58 to 77%), greenhouse gas (GHG) emissions (33 to 82%), and particulate matter (PM2.5) emissions (15 to 54%) in comparison with gasoline. However, volatile organic compounds (VOCs) and other criteria pollutants such as nitrogen oxides (NOx), particulate matter (PM10), and sulfur dioxides (SO x) were higher for E85s than those from gasoline. Nitrogen rate above 56 kg N ha –1 yielded no increased biomass production benefits; but did increase (up to twofold) GHG, VOCs, and criteria pollutants. Lower blend (E10) results were closely similar to those from gasoline. The landscape topography also influenced life cycle impacts. Biomass grown at the footslope of fertilized plots led to higher switchgrass biomass yield, lower GHG, VOCs, and criteria pollutants in comparison with those at the shoulder position. Lastly, results also showed that replacing switchgrass before maximum stand life (10–20 years.) can further reduce the energy and emissions reduction benefits.« less

Low Cycle Fatigue and Creep-Fatigue Behavior of Alloy 617 at High Temperature

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cabet, Celine; Carroll, Laura; Wright, Richard

Alloy 617 is the leading candidate material for an intermediate heat exchanger (IHX) application of the Very High Temperature Nuclear Reactor (VHTR), expected to have an outlet temperature as high as 950 degrees C. Acceptance of Alloy 617 in Section III of the ASME Code for nuclear construction requires a detailed understanding of the creep-fatigue behavior. Initial creep-fatigue work on Alloy 617 suggests a more dominant role of environment with increasing temperature and/or hold times evidenced through changes in creep-fatigue crack growth mechanism/s and failure life. Continuous cycle fatigue and creep-fatigue testing of Alloy 617 was conducted at 950 degreesmore » C and 0.3% and 0.6% total strain in air to simulate damage modes expected in a VHTR application. Continuous cycle specimens exhibited transgranular cracking. Intergranular cracking was observed in the creep-fatigue specimens, although evidence of grain boundary cavitation was not observed. Despite the absence of grain boundary cavitation to accelerate crack propagation, the addition of a hold time at peak tensile strain was detrimental to cycle life. This suggests that creepfatigue interaction may occur by a different mechanism or that the environment may be partially responsible for accelerating failure.« less

Recent advances in lunar base simulation

NASA Astrophysics Data System (ADS)

Johenning, B.; Koelle, H. H.

This article reports about the results of the latest computer runs of a lunar base simulation model. The lunar base consists of 20 facilities for lunar mining, processing and fabrication. The infrastructure includes solar and nuclear power plants, a central workshop, habitat and farm. Lunar products can be used for construction of solar power systems (SPS) or other spacecraft at several space locations. The simulation model evaluates the mass, energy and manpower flows between the elements of the system as well as system cost and cost of products on an annual basis for a given operational period. The 1983 standard model run over a fifty-years life cycle (beginning about the year 2000) was accomplished for a mean annual production volume of 78 180 Mg of hardware products for export resulting in average specific manufacturing cost of 8.4 $/kg and total annual cost of 1.25 billion dollars during the life cycle. The reference space transportation system uses LOX/LH 2 propulsion for which at the average 210 500 Mg LOX per year is produced on the moon. The sensitivity analysis indicates the importance of bootstrapping as well as the influence of market size, space transportation cost and specific resources demand on the mean lunar manufacturing cost. The option using lunar resources turns out to be quite attractive from the economical viewpoint. Systems analysis by this lunar base model and further trade-offs will be a useful tool to confirm this.

Life Cycle Energy Analysis of Reclaimed Water Reuse Projects in Beijing.

PubMed

Fan, Yupeng; Guo, Erhui; Zhai, Yuanzheng; Chang, Andrew C; Qiao, Qi; Kang, Peng

2018-01-01

  To illustrate the benefits of water reuse project, the process-based life cycle analysis (LCA) could be combined with input-output LCA to evaluate the water reuse project. Energy is the only evaluation parameter used in this study. Life cycle assessment of all energy inputs (LCEA) is completed mainly by the life cycle inventory (LCI), taking into account the full life cycle including the construction, the operation, and the demolition phase of the project. Assessment of benefit from water reuse during the life cycle should focus on wastewater discharge reduction and water-saving benefits. The results of LCEA of Beijing water reuse project built in 2014 in a comprehensive way shows that the benefits obtained from the reclaimed water reuse far exceed the life cycle energy consumption. In this paper, the authors apply the LCEA model to estimate the benefits of reclaimed water reuse projects quantitatively.

10 CFR 436.20 - Net savings.

Code of Federal Regulations, 2013 CFR

2013-01-01

... Life Cycle Cost Analyses § 436.20 Net savings. For a retrofit project, net savings may be found by subtracting life cycle costs based on the proposed project from life cycle costs based on not having it. For a new building design, net savings is the difference between the life cycle costs of an alternative...

10 CFR 436.20 - Net savings.

Code of Federal Regulations, 2014 CFR

2014-01-01

... Life Cycle Cost Analyses § 436.20 Net savings. For a retrofit project, net savings may be found by subtracting life cycle costs based on the proposed project from life cycle costs based on not having it. For a new building design, net savings is the difference between the life cycle costs of an alternative...

10 CFR 436.42 - Evaluation of Life-Cycle Cost Effectiveness.

Code of Federal Regulations, 2014 CFR

2014-01-01

... 10 Energy 3 2014-01-01 2014-01-01 false Evaluation of Life-Cycle Cost Effectiveness. 436.42... PROGRAMS Agency Procurement of Energy Efficient Products § 436.42 Evaluation of Life-Cycle Cost...) ENERGY STAR qualified and FEMP designated products may be assumed to be life-cycle cost-effective. (b) In...

10 CFR 435.306 - Selecting a life cycle effective proposed building design.

Code of Federal Regulations, 2013 CFR

2013-01-01

... 10 Energy 3 2013-01-01 2013-01-01 false Selecting a life cycle effective proposed building design... Residential Buildings § 435.306 Selecting a life cycle effective proposed building design. In selecting... prototype, has the highest Net Savings or lowest total life cycle costs calculated in compliance with...

10 CFR 436.42 - Evaluation of Life-Cycle Cost Effectiveness.

Code of Federal Regulations, 2012 CFR

2012-01-01

... 10 Energy 3 2012-01-01 2012-01-01 false Evaluation of Life-Cycle Cost Effectiveness. 436.42... PROGRAMS Agency Procurement of Energy Efficient Products § 436.42 Evaluation of Life-Cycle Cost...) ENERGY STAR qualified and FEMP designated products may be assumed to be life-cycle cost-effective. (b) In...

10 CFR 436.42 - Evaluation of Life-Cycle Cost Effectiveness.

Code of Federal Regulations, 2013 CFR

2013-01-01

... 10 Energy 3 2013-01-01 2013-01-01 false Evaluation of Life-Cycle Cost Effectiveness. 436.42... PROGRAMS Agency Procurement of Energy Efficient Products § 436.42 Evaluation of Life-Cycle Cost...) ENERGY STAR qualified and FEMP designated products may be assumed to be life-cycle cost-effective. (b) In...

10 CFR 435.306 - Selecting a life cycle effective proposed building design.

Code of Federal Regulations, 2014 CFR

2014-01-01

... 10 Energy 3 2014-01-01 2014-01-01 false Selecting a life cycle effective proposed building design... Residential Buildings § 435.306 Selecting a life cycle effective proposed building design. In selecting... prototype, has the highest Net Savings or lowest total life cycle costs calculated in compliance with...

10 CFR 435.306 - Selecting a life cycle effective proposed building design.

Code of Federal Regulations, 2012 CFR

2012-01-01

... 10 Energy 3 2012-01-01 2012-01-01 false Selecting a life cycle effective proposed building design... Residential Buildings § 435.306 Selecting a life cycle effective proposed building design. In selecting... prototype, has the highest Net Savings or lowest total life cycle costs calculated in compliance with...

10 CFR 436.20 - Net savings.

Code of Federal Regulations, 2012 CFR

2012-01-01

... Life Cycle Cost Analyses § 436.20 Net savings. For a retrofit project, net savings may be found by subtracting life cycle costs based on the proposed project from life cycle costs based on not having it. For a new building design, net savings is the difference between the life cycle costs of an alternative...

10 CFR 433.8 - Life-cycle costing.

Code of Federal Regulations, 2011 CFR

2011-01-01

... 10 Energy 3 2011-01-01 2011-01-01 false Life-cycle costing. 433.8 Section 433.8 Energy DEPARTMENT... FEDERAL COMMERCIAL AND MULTI-FAMILY HIGH-RISE RESIDENTIAL BUILDINGS § 433.8 Life-cycle costing. Each Federal agency shall determine life-cycle cost-effectiveness by using the procedures set out in subpart A...

78 FR 47012 - Developing Software Life Cycle Processes Used in Safety Systems of Nuclear Power Plants

Federal Register 2010, 2011, 2012, 2013, 2014

2013-08-02

... NUCLEAR REGULATORY COMMISSION [NRC-2012-0195] Developing Software Life Cycle Processes Used in... revised regulatory guide (RG), revision 1 of RG 1.173, ``Developing Software Life Cycle Processes for... Developing a Software Project Life Cycle Process,'' issued 2006, with the clarifications and exceptions as...

10 CFR 433.8 - Life-cycle costing.

Code of Federal Regulations, 2010 CFR

2010-01-01

... 10 Energy 3 2010-01-01 2010-01-01 false Life-cycle costing. 433.8 Section 433.8 Energy DEPARTMENT... FEDERAL COMMERCIAL AND MULTI-FAMILY HIGH-RISE RESIDENTIAL BUILDINGS § 433.8 Life-cycle costing. Each Federal agency shall determine life-cycle cost-effectiveness by using the procedures set out in subpart A...

DEVELOPMENT OF THE METHOD AND U.S. NORMALIZATION DATABASE FOR LIFE CYCLE IMPACT ASSESSMENT AND SUSTAINABILITY METRICS

EPA Science Inventory

Normalization is an optional step within Life Cycle Impact Assessment (LCIA) that may be used to assist in the interpretation of life cycle inventory data as well as, life cycle impact assessment results. Normalization transforms the magnitude of LCI and LCIA results into relati...

10 CFR 436.42 - Evaluation of Life-Cycle Cost Effectiveness.

Code of Federal Regulations, 2010 CFR

2010-01-01

... 10 Energy 3 2010-01-01 2010-01-01 false Evaluation of Life-Cycle Cost Effectiveness. 436.42... PROGRAMS Agency Procurement of Energy Efficient Products § 436.42 Evaluation of Life-Cycle Cost...) ENERGY STAR qualified and FEMP designated products may be assumed to be life-cycle cost-effective. (b) In...

10 CFR 435.306 - Selecting a life cycle effective proposed building design.

Code of Federal Regulations, 2010 CFR

2010-01-01

... 10 Energy 3 2010-01-01 2010-01-01 false Selecting a life cycle effective proposed building design... Residential Buildings § 435.306 Selecting a life cycle effective proposed building design. In selecting... prototype, has the highest Net Savings or lowest total life cycle costs calculated in compliance with...

Residential Preferences and Moving Behavior: A Family Life Cycle Analysis.

ERIC Educational Resources Information Center

McAuley, William J.; Nutty, Cheri L.

The relationship of family life cycle changes to housing preferences and residential mobility is examined. Two residential decision-making issues are explored in detail--how family life cycle stages influence what people view as important to their choice of residential setting and what individuals at different family life cycle stages view as the…

10 CFR 436.20 - Net savings.

Code of Federal Regulations, 2010 CFR

2010-01-01

... Life Cycle Cost Analyses § 436.20 Net savings. For a retrofit project, net savings may be found by subtracting life cycle costs based on the proposed project from life cycle costs based on not having it. For a new building design, net savings is the difference between the life cycle costs of an alternative...

10 CFR 436.20 - Net savings.

Code of Federal Regulations, 2011 CFR

2011-01-01

... Life Cycle Cost Analyses § 436.20 Net savings. For a retrofit project, net savings may be found by subtracting life cycle costs based on the proposed project from life cycle costs based on not having it. For a new building design, net savings is the difference between the life cycle costs of an alternative...

10 CFR 436.42 - Evaluation of Life-Cycle Cost Effectiveness.

Code of Federal Regulations, 2011 CFR

2011-01-01

... the life-cycle cost analysis method in part 436, subpart A, of title 10 of the Code of Federal... 10 Energy 3 2011-01-01 2011-01-01 false Evaluation of Life-Cycle Cost Effectiveness. 436.42... PROGRAMS Agency Procurement of Energy Efficient Products § 436.42 Evaluation of Life-Cycle Cost...

Large-Scale NASA Science Applications on the Columbia Supercluster

NASA Technical Reports Server (NTRS)

Brooks, Walter

2005-01-01

Columbia, NASA's newest 61 teraflops supercomputer that became operational late last year, is a highly integrated Altix cluster of 10,240 processors, and was named to honor the crew of the Space Shuttle lost in early 2003. Constructed in just four months, Columbia increased NASA's computing capability ten-fold, and revitalized the Agency's high-end computing efforts. Significant cutting-edge science and engineering simulations in the areas of space and Earth sciences, as well as aeronautics and space operations, are already occurring on this largest operational Linux supercomputer, demonstrating its capacity and capability to accelerate NASA's space exploration vision. The presentation will describe how an integrated environment consisting not only of next-generation systems, but also modeling and simulation, high-speed networking, parallel performance optimization, and advanced data analysis and visualization, is being used to reduce design cycle time, accelerate scientific discovery, conduct parametric analysis of multiple scenarios, and enhance safety during the life cycle of NASA missions. The talk will conclude by discussing how NAS partnered with various NASA centers, other government agencies, computer industry, and academia, to create a national resource in large-scale modeling and simulation.

Simulated Carbon Cycling in a Model Microbial Mat.

NASA Astrophysics Data System (ADS)

Decker, K. L.; Potter, C. S.

2006-12-01

We present here the novel addition of detailed organic carbon cycling to our model of a hypersaline microbial mat ecosystem. This ecosystem model, MBGC (Microbial BioGeoChemistry), simulates carbon fixation through oxygenic and anoxygenic photosynthesis, and the release of C and electrons for microbial heterotrophs via cyanobacterial exudates and also via a pool of dead cells. Previously in MBGC, the organic portion of the carbon cycle was simplified into a black-box rate of accumulation of simple and complex organic compounds based on photosynthesis and mortality rates. We will discuss the novel inclusion of fermentation as a source of carbon and electrons for use in methanogenesis and sulfate reduction, and the influence of photorespiration on labile carbon exudation rates in cyanobacteria. We will also discuss the modeling of decomposition of dead cells and the ultimate release of inorganic carbon. The detailed modeling of organic carbon cycling is important to the accurate representation of inorganic carbon flux through the mat, as well as to accurate representation of growth models of the heterotrophs under different environmental conditions. Because the model ecosystem is an analog of ancient microbial mats that had huge impacts on the atmosphere of early earth, this MBGC can be useful as a biological component to either early earth models or models of other planets that potentially harbor life.

Fatigue crack growth and life prediction under mixed-mode loading

NASA Astrophysics Data System (ADS)

Sajith, S.; Murthy, K. S. R. K.; Robi, P. S.

2018-04-01

Fatigue crack growth life as a function of crack length is essential for the prevention of catastrophic failures from damage tolerance perspective. In damage tolerance design approach, principles of fracture mechanics are usually applied to predict the fatigue life of structural components. Numerical prediction of crack growth versus number of cycles is essential in damage tolerance design. For cracks under mixed mode I/II loading, modified Paris law (d/a d N =C (ΔKe q ) m ) along with different equivalent stress intensity factor (ΔKeq) model is used for fatigue crack growth rate prediction. There are a large number of ΔKeq models available for the mixed mode I/II loading, the selection of proper ΔKeq model has significant impact on fatigue life prediction. In the present investigation, the performance of ΔKeq models in fatigue life prediction is compared with respect to the experimental findings as there are no guidelines/suggestions available on the selection of these models for accurate and/or conservative predictions of fatigue life. Within the limitations of availability of experimental data and currently available numerical simulation techniques, the results of present study attempt to outline models that would provide accurate and conservative life predictions. Such a study aid the numerical analysts or engineers in the proper selection of the model for numerical simulation of the fatigue life. Moreover, the present investigation also suggests a procedure to enhance the accuracy of life prediction using Paris law.

A Model of BGA Thermal Fatigue Life Prediction Considering Load Sequence Effects

PubMed Central

Hu, Weiwei; Li, Yaqiu; Sun, Yufeng; Mosleh, Ali

2016-01-01

Accurate testing history data is necessary for all fatigue life prediction approaches, but such data is always deficient especially for the microelectronic devices. Additionally, the sequence of the individual load cycle plays an important role in physical fatigue damage. However, most of the existing models based on the linear damage accumulation rule ignore the sequence effects. This paper proposes a thermal fatigue life prediction model for ball grid array (BGA) packages to take into consideration the load sequence effects. For the purpose of improving the availability and accessibility of testing data, a new failure criterion is discussed and verified by simulation and experimentation. The consequences for the fatigue underlying sequence load conditions are shown. PMID:28773980

2007 Armaments Technology Seminar and Exhibition - Joint Munitions and Lethality Life Cycle Management Command

DTIC Science & Technology

2007-06-13

MTOP APS LOS-KE TBX Ceramic Barrel Novel Energetic Materials for the Future Force Multimode HPM and Laser Induced Plasma Channel Technology T Force...in one item • Enhanced incendiary device • Replacement of environmentally unfriendly materials • Insensitive munitions compliance 12 Pyrotechnics...simulators • Pocket sized hand held signals • Replacement of environmentally unfriendly materials • Improve pyrotechnic characteristics with nanotechnologies

Quantitative Analysis of Hepatitis C NS5A Viral Protein Dynamics on the ER Surface.

PubMed

Knodel, Markus M; Nägel, Arne; Reiter, Sebastian; Vogel, Andreas; Targett-Adams, Paul; McLauchlan, John; Herrmann, Eva; Wittum, Gabriel

2018-01-08

Exploring biophysical properties of virus-encoded components and their requirement for virus replication is an exciting new area of interdisciplinary virological research. To date, spatial resolution has only rarely been analyzed in computational/biophysical descriptions of virus replication dynamics. However, it is widely acknowledged that intracellular spatial dependence is a crucial component of virus life cycles. The hepatitis C virus-encoded NS5A protein is an endoplasmatic reticulum (ER)-anchored viral protein and an essential component of the virus replication machinery. Therefore, we simulate NS5A dynamics on realistic reconstructed, curved ER surfaces by means of surface partial differential equations (sPDE) upon unstructured grids. We match the in silico NS5A diffusion constant such that the NS5A sPDE simulation data reproduce experimental NS5A fluorescence recovery after photobleaching (FRAP) time series data. This parameter estimation yields the NS5A diffusion constant. Such parameters are needed for spatial models of HCV dynamics, which we are developing in parallel but remain qualitative at this stage. Thus, our present study likely provides the first quantitative biophysical description of the movement of a viral component. Our spatio-temporal resolved ansatz paves new ways for understanding intricate spatial-defined processes central to specfic aspects of virus life cycles.

Techno-environmental assessment of the green biorefinery concept: Combining process simulation and life cycle assessment at an early design stage.

PubMed

Corona, Andrea; Ambye-Jensen, Morten; Vega, Giovanna Croxatto; Hauschild, Michael Zwicky; Birkved, Morten

2018-09-01

The Green biorefinery (GBR) is a biorefinery concept that converts fresh biomass into value-added products. The present study combines a Process Flowsheet Simulation (PFS) and Life Cycle Assessment (LCA) to evaluate the technical and environmental performance of different GBR configurations and the cascading utilization of the GBR output. The GBR configurations considered in this study, test alternatives in the three main steps of green-biorefining: fractionation, precipitation, and protein separation. The different cascade utilization alternatives analyse different options for press-pulp utilization, and the LCA results show that the environmental profile of the GBR is highly affected by the utilization of the press-pulp and thus by the choice of conventional product replaced by the press-pulp. Furthermore, scenario analysis of different GBR configurations shows that higher benefits can be achieved by increasing product yields rather than lowering energy consumption. Green biorefining is shown to be an interesting biorefining concept, especially in a Danish context. Biorefining of green biomass is technically feasible and can bring environmental savings, when compared to conventional production methods. However, the savings will be determined by the processing involved in each conversion stage and on the cascade utilization of the different platform products. Copyright © 2018 Elsevier B.V. All rights reserved.

Numerical simulation of the fatigue behavior of additive manufactured titanium porous lattice structures.

PubMed

Zargarian, A; Esfahanian, M; Kadkhodapour, J; Ziaei-Rad, S

2016-03-01

In this paper, the effects of cell geometry and relative density on the high-cycle fatigue behavior of Titanium scaffolds produced by selective laser melting and electron beam melting techniques were numerically investigated by finite element analysis. The regular titanium lattice samples with three different unit cell geometries, namely, diamond, rhombic dodecahedron and truncated cuboctahedron, and the relative density range of 0.1-0.3 were analyzed under uniaxial cyclic compressive loading. A failure event based algorithm was employed to simulate fatigue failure in the cellular material. Stress-life approach was used to model fatigue failure of both bulk (struts) and cellular material. The predicted fatigue life and the damage pattern of all three structures were found to be in good agreement with the experimental fatigue investigations published in the literature. The results also showed that the relationship between fatigue strength and cycles to failure obeyed the power law. The coefficient of power function was shown to depend on relative density, geometry and fatigue properties of the bulk material while the exponent was only dependent on the fatigue behavior of the bulk material. The results also indicated the failure surface at an angle of 45° to the loading direction. Copyright © 2015 Elsevier B.V. All rights reserved.

Cost versus life cycle assessment-based environmental impact optimization of drinking water production plants.

PubMed

Capitanescu, F; Rege, S; Marvuglia, A; Benetto, E; Ahmadi, A; Gutiérrez, T Navarrete; Tiruta-Barna, L

2016-07-15

Empowering decision makers with cost-effective solutions for reducing industrial processes environmental burden, at both design and operation stages, is nowadays a major worldwide concern. The paper addresses this issue for the sector of drinking water production plants (DWPPs), seeking for optimal solutions trading-off operation cost and life cycle assessment (LCA)-based environmental impact while satisfying outlet water quality criteria. This leads to a challenging bi-objective constrained optimization problem, which relies on a computationally expensive intricate process-modelling simulator of the DWPP and has to be solved with limited computational budget. Since mathematical programming methods are unusable in this case, the paper examines the performances in tackling these challenges of six off-the-shelf state-of-the-art global meta-heuristic optimization algorithms, suitable for such simulation-based optimization, namely Strength Pareto Evolutionary Algorithm (SPEA2), Non-dominated Sorting Genetic Algorithm (NSGA-II), Indicator-based Evolutionary Algorithm (IBEA), Multi-Objective Evolutionary Algorithm based on Decomposition (MOEA/D), Differential Evolution (DE), and Particle Swarm Optimization (PSO). The results of optimization reveal that good reduction in both operating cost and environmental impact of the DWPP can be obtained. Furthermore, NSGA-II outperforms the other competing algorithms while MOEA/D and DE perform unexpectedly poorly. Copyright © 2016 Elsevier Ltd. All rights reserved.

CALiPER Report 21.3: Cost-Effectiveness of Linear (T8) LED Lamps

DOE Office of Scientific and Technical Information (OSTI.GOV)

Miller, Naomi J.; Perrin, Tess E.; Royer, Michael P.

2014-05-27

Meeting performance expectations is important for driving adoption of linear LED lamps, but cost-effectiveness may be an overriding factor in many cases. Linear LED lamps cost more initially than fluorescent lamps, but energy and maintenance savings may mean that the life-cycle cost is lower. This report details a series of life-cycle cost simulations that compared a two-lamp troffer using LED lamps (38 W total power draw) or fluorescent lamps (51 W total power draw) over a 10-year study period. Variables included LED system cost ($40, $80, or $120), annual operating hours (2,000 hours or 4,000 hours), LED installation time (15more » minutes or 30 minutes), and melded electricity rate ($0.06/kWh, $0.12/kWh, $0.18/kWh, or $0.24/kWh). A full factorial of simulations allows users to interpolate between these values to aid in making rough estimates of economic feasibility for their own projects. In general, while their initial cost premium remains high, linear LED lamps are more likely to be cost-effective when electric utility rates are higher than average and hours of operation are long, and if their installation time is shorter.« less

CALiPER Report 21.3. Cost Effectiveness of Linear (T8) LED Lamps

DOE Office of Scientific and Technical Information (OSTI.GOV)

None

2014-05-01

Meeting performance expectations is important for driving adoption of linear LED lamps, but cost-effectiveness may be an overriding factor in many cases. Linear LED lamps cost more initially than fluorescent lamps, but energy and maintenance savings may mean that the life-cycle cost is lower. This report details a series of life-cycle cost simulations that compared a two-lamp troffer using LED lamps (38 W total power draw) or fluorescent lamps (51 W total power draw) over a 10-year study period. Variables included LED system cost ($40, $80, or $120), annual operating hours (2,000 hours or 4,000 hours), LED installation time (15more » minutes or 30 minutes), and melded electricity rate ($0.06/kWh, $0.12/kWh, $0.18/kWh, or $0.24/kWh). A full factorial of simulations allows users to interpolate between these values to aid in making rough estimates of economic feasibility for their own projects. In general, while their initial cost premium remains high, linear LED lamps are more likely to be cost-effective when electric utility rates are higher than average and hours of operation are long, and if their installation time is shorter.« less

Quantitative Analysis of Hepatitis C NS5A Viral Protein Dynamics on the ER Surface

PubMed Central

Nägel, Arne; Reiter, Sebastian; Vogel, Andreas; McLauchlan, John; Herrmann, Eva; Wittum, Gabriel

2018-01-01

Exploring biophysical properties of virus-encoded components and their requirement for virus replication is an exciting new area of interdisciplinary virological research. To date, spatial resolution has only rarely been analyzed in computational/biophysical descriptions of virus replication dynamics. However, it is widely acknowledged that intracellular spatial dependence is a crucial component of virus life cycles. The hepatitis C virus-encoded NS5A protein is an endoplasmatic reticulum (ER)-anchored viral protein and an essential component of the virus replication machinery. Therefore, we simulate NS5A dynamics on realistic reconstructed, curved ER surfaces by means of surface partial differential equations (sPDE) upon unstructured grids. We match the in silico NS5A diffusion constant such that the NS5A sPDE simulation data reproduce experimental NS5A fluorescence recovery after photobleaching (FRAP) time series data. This parameter estimation yields the NS5A diffusion constant. Such parameters are needed for spatial models of HCV dynamics, which we are developing in parallel but remain qualitative at this stage. Thus, our present study likely provides the first quantitative biophysical description of the movement of a viral component. Our spatio-temporal resolved ansatz paves new ways for understanding intricate spatial-defined processes central to specfic aspects of virus life cycles. PMID:29316722

Movement Complexity and Neuromechanical Factors Affect the Entropic Half-Life of Myoelectric Signals

PubMed Central

Hodson-Tole, Emma F.; Wakeling, James M.

2017-01-01

Appropriate neuromuscular functioning is essential for survival and features underpinning motor control are present in myoelectric signals recorded from skeletal muscles. One approach to quantify control processes related to function is to assess signal variability using measures such as Sample Entropy. Here we developed a theoretical framework to simulate the effect of variability in burst duration, activation duty cycle, and intensity on the Entropic Half-Life (EnHL) in myoelectric signals. EnHLs were predicted to be <40 ms, and to vary with fluctuations in myoelectric signal amplitude and activation duty cycle. Comparison with myoelectic data from rats walking and running at a range of speeds and inclines confirmed the range of EnHLs, however, the direction of EnHL change in response to altered locomotor demand was not correctly predicted. The discrepancy reflected different associations between the ratio of the standard deviation and mean signal intensity (Ist:It¯) and duty factor in simulated and physiological data, likely reflecting additional information in the signals from the physiological data (e.g., quiescent phase content; variation in action potential shapes). EnHL could have significant value as a novel marker of neuromuscular responses to alterations in perceived locomotor task complexity and intensity. PMID:28974932

KOH concentration effect on cycle life of nickel-hydrogen cells

NASA Technical Reports Server (NTRS)

Lim, Hong S.; Verzwyvelt, S. A.

1987-01-01

A cycle life test of Ni/H2 cells containing electrolytes of various KOH concentrations and a sintered type nickel electrode was carried out at 23 C using a 45 min accelerated low Earth orbit (LEO) cycle regime at 80 percent depth of discharge. One of three cells containing 26 percent KOH has achieved over 28,000 cycles, and the other two 19,000 cycles, without a sign of failure. Two other cells containing 31 percent KOH electrolyte, which is the concentration presently used in aerospace cells, failed after 2,979 and 3,620 cycles. This result indicates that the cycle life of the present type of Ni/H2 cells may be extended by a factor of 5 to 10 simply by lowering the KOH concentration. Long cycle life of a Ni/H2 battery at high depth-of-discharge operation is desired, particularly for an LEO spacecraft application. Typically, battery life of about 30,000 cycles is required for a five year mission in an LEO. Such a cycle life with presently available cells can be assured only at a very low depth-of-discharge operation. Results of testing already show that the cycle life of an Ni/H2 cell is tremendously improved by simply using an electrolyte of low KOH concentration.

10 CFR 455.64 - Life-cycle cost methodology.

Code of Federal Regulations, 2011 CFR

2011-01-01

... 10 Energy 3 2011-01-01 2011-01-01 false Life-cycle cost methodology. 455.64 Section 455.64 Energy..., Hospitals, Units of Local Government, and Public Care Institutions § 455.64 Life-cycle cost methodology. (a) The life-cycle cost methodology under § 455.63(b) of this part is a systematic comparison of the...

NREL: U.S. Life Cycle Inventory Database - About the LCI Database Project

Science.gov Websites

About the LCI Database Project The U.S. Life Cycle Inventory (LCI) Database is a publicly available data collection and analysis methods. Finding consistent and transparent LCI data for life cycle and maintain the database. The 2009 U.S. Life Cycle Inventory (LCI) Data Stakeholder meeting was an

10 CFR 455.64 - Life-cycle cost methodology.

Code of Federal Regulations, 2010 CFR

2010-01-01

... 10 Energy 3 2010-01-01 2010-01-01 false Life-cycle cost methodology. 455.64 Section 455.64 Energy..., Hospitals, Units of Local Government, and Public Care Institutions § 455.64 Life-cycle cost methodology. (a) The life-cycle cost methodology under § 455.63(b) of this part is a systematic comparison of the...

Alternative Fuels Data Center: Benefits and Considerations of Electricity

Science.gov Websites

tailpipe emissions when in all-electric mode. The life cycle emissions of an EV or PHEV depend on the low-polluting energy sources for electricity production, plug-in vehicles typically have a life cycle strong life cycle emissions benefit. Use the Vehicle Cost Calculator to compare life cycle emissions of

UTILITY OF A FULL LIFE-CYCLE COPEPOD BIOASSAY APPROACH FOR ASSESSMENT OF SEDIMENT-ASSOCIATED CONTAMINANT MIXTURES. (R825279)

EPA Science Inventory

Abstract

We compared a 21 day full life-cycle bioassay with an existing 14 day partial life-cycle bioassay for two species of meiobenthic copepods, Microarthridion littorale and Amphiascus tenuiremis. We hypothesized that full life-cycle tests would bette...

The Early Years: "Life" Science

ERIC Educational Resources Information Center

Ashbrook, Peggy

2013-01-01

Talking about death as part of a life cycle is often ignored or spoken about in hushed tones in early childhood. Books with "life cycle" in the title often do not include the death of the living organism in the information about the cycle. The concept of a complete life cycle does not appear in "A Framework for K-12 Science…

Alberta Carpenter | NREL

Science.gov Websites

cycle assessment in industrial by-product management, waste management, biofuels and manufacturing technologies Life cycle inventory database management Research Interests Life cycle assessment Life cycle inventory management Biofuels Advanced manufacturing Supply chain analysis Education Ph.D in environmental

NREL: U.S. Life Cycle Inventory Database - Publications

Science.gov Websites

Publications Planning Documents U.S. Life Cycle Inventory Database Roadmap, February 2009 U.S. Life Cycle Inventory User Survey, February 2009 U.S. LCI Database Factsheet, March 2005 User's Guide for Life

Combining agent-based modeling and life cycle assessment for the evaluation of mobility policies.

PubMed

Florent, Querini; Enrico, Benetto

2015-02-03

This article presents agent-based modeling (ABM) as a novel approach for consequential life cycle assessment (C-LCA) of large scale policies, more specifically mobility-related policies. The approach is validated at the Luxembourgish level (as a first case study). The agent-based model simulates the car market (sales, use, and dismantling) of the population of users in the period 2013-2020, following the implementation of different mobility policies and available electric vehicles. The resulting changes in the car fleet composition as well as the hourly uses of the vehicles are then used to derive consistent LCA results, representing the consequences of the policies. Policies will have significant environmental consequences: when using ReCiPe2008, we observe a decrease of global warming, fossil depletion, acidification, ozone depletion, and photochemical ozone formation and an increase of metal depletion, ionizing radiations, marine eutrophication, and particulate matter formation. The study clearly shows that the extrapolation of LCA results for the circulating fleet at national scale following the introduction of the policies from the LCAs of single vehicles by simple up-scaling (using hypothetical deployment scenarios) would be flawed. The inventory has to be directly conducted at full scale and to this aim, ABM is indeed a promising approach, as it allows identifying and quantifying emerging effects while modeling the Life Cycle Inventory of vehicles at microscale through the concept of agents.

Evaluating uncertainty in environmental life-cycle assessment. A case study comparing two insulation options for a Dutch one-family dwelling.

PubMed

Huijbregts, Mark A J; Gilijamse, Wim; Ragas, Ad M J; Reijnders, Lucas

2003-06-01

The evaluation of uncertainty is relatively new in environmental life-cycle assessment (LCA). It provides useful information to assess the reliability of LCA-based decisions and to guide future research toward reducing uncertainty. Most uncertainty studies in LCA quantify only one type of uncertainty, i.e., uncertainty due to input data (parameter uncertainty). However, LCA outcomes can also be uncertain due to normative choices (scenario uncertainty) and the mathematical models involved (model uncertainty). The present paper outlines a new methodology that quantifies parameter, scenario, and model uncertainty simultaneously in environmental life-cycle assessment. The procedure is illustrated in a case study that compares two insulation options for a Dutch one-family dwelling. Parameter uncertainty was quantified by means of Monte Carlo simulation. Scenario and model uncertainty were quantified by resampling different decision scenarios and model formulations, respectively. Although scenario and model uncertainty were not quantified comprehensively, the results indicate that both types of uncertainty influence the case study outcomes. This stresses the importance of quantifying parameter, scenario, and model uncertainty simultaneously. The two insulation options studied were found to have significantly different impact scores for global warming, stratospheric ozone depletion, and eutrophication. The thickest insulation option has the lowest impact on global warming and eutrophication, and the highest impact on stratospheric ozone depletion.

Navigating environmental, economic, and technological trade-offs in the design and operation of submerged anaerobic membrane bioreactors (AnMBRs).

PubMed

Pretel, R; Shoener, B D; Ferrer, J; Guest, J S

2015-12-15

Anaerobic membrane bioreactors (AnMBRs) enable energy recovery from wastewater while simultaneously achieving high levels of treatment. The objective of this study was to elucidate how detailed design and operational decisions of submerged AnMBRs influence the technological, environmental, and economic sustainability of the system across its life cycle. Specific design and operational decisions evaluated included: solids retention time (SRT), mixed liquor suspended solids (MLSS) concentration, sludge recycling ratio (r), flux (J), and specific gas demand per membrane area (SGD). The possibility of methane recovery (both as biogas and as soluble methane in reactor effluent) and bioenergy production, nutrient recovery, and final destination of the sludge (land application, landfill, or incineration) were also evaluated. The implications of these design and operational decisions were characterized by leveraging a quantitative sustainable design (QSD) framework which integrated steady-state performance modeling across seasonal temperatures (using pilot-scale experimental data and the simulating software DESASS), life cycle cost (LCC) analysis, and life cycle assessment (LCA). Sensitivity and uncertainty analyses were used to characterize the relative importance of individual design decisions, and to navigate trade-offs across environmental, economic, and technological criteria. Based on this analysis, there are design and operational conditions under which submerged AnMBRs could be net energy positive and contribute to the pursuit of carbon negative wastewater treatment. Copyright © 2015 Elsevier Ltd. All rights reserved.

Autonomy and integration in complex parasite life cycles.

PubMed

Benesh, Daniel P

2016-12-01

Complex life cycles are common in free-living and parasitic organisms alike. The adaptive decoupling hypothesis postulates that separate life cycle stages have a degree of developmental and genetic autonomy, allowing them to be independently optimized for dissimilar, competing tasks. That is, complex life cycles evolved to facilitate functional specialization. Here, I review the connections between the different stages in parasite life cycles. I first examine evolutionary connections between life stages, such as the genetic coupling of parasite performance in consecutive hosts, the interspecific correlations between traits expressed in different hosts, and the developmental and functional obstacles to stage loss. Then, I evaluate how environmental factors link life stages through carryover effects, where stressful larval conditions impact parasites even after transmission to a new host. There is evidence for both autonomy and integration across stages, so the relevant question becomes how integrated are parasite life cycles and through what mechanisms? By highlighting how genetics, development, selection and the environment can lead to interdependencies among successive life stages, I wish to promote a holistic approach to studying complex life cycle parasites and emphasize that what happens in one stage is potentially highly relevant for later stages.

Development and infectious disease in hosts with complex life cycles.

PubMed

Searle, Catherine L; Xie, Gisselle Yang; Blaustein, Andrew R

2013-01-01

Metamorphosis is often characterized by profound changes in morphology and physiology that can affect the dynamics of species interactions. For example, the interaction between a pathogen and its host may differ depending on the life stage of the host or pathogen. One pathogen that infects hosts with complex life cycles is the emerging fungal pathogen of amphibians, Batrachochytrium dendrobatidis (Bd). We sought to determine how conditions at the larval stage can affect variation in development and patterns of Bd infection across amphibian life stages. We used outdoor experimental mesocosms to simulate natural pond habitats and manipulated the presence of Bd, the larval density, and the number of host species in larvae of two co-occurring amphibian species (Rana cascadae and Pseudacris regilla). We found that infection differed between species throughout development; P. regilla consistently had higher infection severity compared to R. cascadae. Additionally, while up to 100% of larvae were infected, only 18.2% of R. cascadae and 81.5% of P. regilla were infected after metamorphosis. This indicates that amphibians have the ability to recover from Bd infection as they undergo metamorphosis. Higher larval densities in P. regilla led to a shorter larval period, and individuals with a shorter larval period had lower infection severity. This led to a trend where P. regilla larvae reared at high densities tended to have lower infection prevalence after metamorphosis. We also found that exposure to Bd increased larval mortality and prolonged the larval period in P. regilla, indicating that P. regilla are susceptible to the negative effects of Bd as larvae. This study demonstrates that host density, species composition, and pathogen exposure may all interact to influence development and infection in hosts with complex life cycles.

Life-history tradeoffs and reproductive cycles in Spotted Owls

USGS Publications Warehouse

Stoelting, Ricka E.; Gutierrez, R.J.; Kendall, William L.; Peery, M. Zachariah

2015-01-01

The study of tradeoffs among life-history traits has long been key to understanding the evolution of life-history strategies. However, more recently, evolutionary ecologists have realized that reproductive costs have the potential to influence population dynamics. Here, we tested for costs of reproduction in the California Spotted Owl (Strix occidentalis occidentalis), and assessed whether costs of reproduction in year t − 1 on reproduction in year t could be responsible for regionally synchronized biennial cycles in reproductive output. Logistic regression analysis and multistate mark–recapture models with state uncertainty revealed that breeding reduced the likelihood of reproducing in the subsequent year by 16% to 38%, but had no influence on subsequent survival. We also found that costs of reproduction in year t − 1 were correlated with climatic conditions in year t, with evidence of higher costs during the dry phase of the El Niño–Southern Oscillation. Using a simulation-based population model, we showed that strong reproductive costs had the potential to create biennial cycles in population-level reproductive output; however, estimated costs of reproduction appeared to be too small to explain patterns observed in Spotted Owls. In the absence of strong reproductive costs, we hypothesize that observed natural cycles in the reproductive output of Spotted Owls are related to as-yet-unmeasured, regionally concordant fluctuations in environmental conditions or prey resources. Despite theoretical evidence for demographic effects, our analyses illustrate that linking tradeoffs to actual changes in population processes will be challenging because of the potential confounding effects of individual and environmental variation.

Performance Evaluation and Modeling of Erosion Resistant Turbine Engine Thermal Barrier Coatings

NASA Technical Reports Server (NTRS)

Miller, Robert A.; Zhu, Dongming; Kuczmarski, Maria

2008-01-01

The erosion resistant turbine thermal barrier coating system is critical to the rotorcraft engine performance and durability. The objective of this work was to determine erosion resistance of advanced thermal barrier coating systems under simulated engine erosion and thermal gradient environments, thus validating a new thermal barrier coating turbine blade technology for future rotorcraft applications. A high velocity burner rig based erosion test approach was established and a new series of rare earth oxide- and TiO2/Ta2O5- alloyed, ZrO2-based low conductivity thermal barrier coatings were designed and processed. The low conductivity thermal barrier coating systems demonstrated significant improvements in the erosion resistance. A comprehensive model based on accumulated strain damage low cycle fatigue is formulated for blade erosion life prediction. The work is currently aiming at the simulated engine erosion testing of advanced thermal barrier coated turbine blades to establish and validate the coating life prediction models.

10 CFR 436.10 - Purpose.

Code of Federal Regulations, 2010 CFR

2010-01-01

... Cycle Cost Analyses § 436.10 Purpose. This subpart establishes a methodology and procedures for estimating and comparing the life cycle costs of Federal buildings, for determining the life cycle cost effectiveness of energy conservation measures and water conservation measures, and for rank ordering life cycle...

Cloud life cycle investigated via high resolution and full microphysics simulations in the surroundings of Manaus, Central Amazonia

NASA Astrophysics Data System (ADS)

Pauliquevis, T.; Gomes, H. B.; Barbosa, H. M.

2014-12-01

In this study we evaluate the skill of WRF model to simulate the actual diurnal cycle of convection in the Amazon basin. Models tipically are not capable to simulate the well documented cycle of 1) shallow cumulus in the morning; 2) towering process around noon; 3) shallow-to-deep convection and rain around 14h (LT). The fail in models is explained by the typical size of shallow cumulus (~0.5 - 2.0 km) and the coarse resolution of models using convection parameterisation (> 20 km). In this study we employed high spatial resolution (Dx = 0.625 km) to reach the shallow cumulus scale. . The simulations corresponds to a dynamical downscaling of ERA-Interim from 25 to 28 February 2013 with 40 vertical levels, 30 minutes outputs,and three nested grids (10 km, 2.5 km, 0.625 km). Improved vegetation (USGS + PROVEG), albedo and greenfrac (computed from MODIS-NDVI + LEAF-2 land surface parameterization), as well as pseudo analysis of soil moisture were used as input data sets, resulting in more realistic precipitation fields when compared to observations in sensitivity tests. Convective parameterization was switched off for the 2.5/0.625 km grids, where cloud formation was solely resolved by the microphysics module (WSM6 scheme, which provided better results). Results showed a significant improved capability of the model to simulate diurnal cycle. Shallow cumulus begin to appear in the first hours in the morning. They were followed by a towering process that culminates with precipitation in the early afternoon, which is a behavior well described by observations but rarely obtained in models. Rain volumes were also realistic (~20 mm for single events) when compared to typical events during the period, which is in the core of the wet season. Cloud fields evolution also differed with respect to Amazonas River bank, which is a clear evidence of the interaction between river breeze and large scale circulation.

Shortening tobacco life cycle accelerates functional gene identification in genomic research.

PubMed

Ning, G; Xiao, X; Lv, H; Li, X; Zuo, Y; Bao, M

2012-11-01

Definitive allocation of function requires the introduction of genetic mutations and analysis of their phenotypic consequences. Novel, rapid and convenient techniques or materials are very important and useful to accelerate gene identification in functional genomics research. Here, over-expression of PmFT (Prunus mume), a novel FT orthologue, and PtFT (Populus tremula) lead to shortening of the tobacco life cycle. A series of novel short life cycle stable tobacco lines (30-50 days) were developed through repeated self-crossing selection breeding. Based on the second transformation via a gusA reporter gene, the promoter from BpFULL1 in silver birch (Betula pendula) and the gene (CPC) from Arabidopsis thaliana were effectively tested using short life cycle tobacco lines. Comparative analysis among wild type, short life cycle tobacco and Arabidopsis transformation system verified that it is optional to accelerate functional gene studies by shortening host plant material life cycle, at least in these short life cycle tobacco lines. The results verified that the novel short life cycle transgenic tobacco lines not only combine the advantages of economic nursery requirements and a simple transformation system, but also provide a robust, effective and stable host system to accelerate gene analysis. Thus, shortening tobacco life cycle strategy is feasible to accelerate heterologous or homologous functional gene identification in genomic research. © 2012 German Botanical Society and The Royal Botanical Society of the Netherlands.

NREL, Johns Hopkins SAIS Develop Method to Quantify Life Cycle Land Use of

Science.gov Websites

Life Cycle Land Use of Electricity from Natural Gas News Release: NREL, Johns Hopkins SAIS Develop Method to Quantify Life Cycle Land Use of Electricity from Natural Gas October 2, 2017 A case study of time provides quantifiable information on the life cycle land use of generating electricity from

REPORT ON ACTIVITY OF TASK FORCE 1 IN THE LIFE CYCLE INVENTORY PROGRAMME: DATA REGISTRY - GLOBAL LIFE CYCLE INVENTORY DATA RESOURCES

EPA Science Inventory

This paper presents a summary of the findings of a report prepared by Task Force 1 of the UNEP/SETAC Life Cycle Initiative on the available Life Cycle Inventory (LCI) databases around the world. An update of a previous summary prepared in May 2002 by Norris and Notten, the repor...

Understanding future emissions from low-carbon power systems by integration of life-cycle assessment and integrated energy modelling

NASA Astrophysics Data System (ADS)

Pehl, Michaja; Arvesen, Anders; Humpenöder, Florian; Popp, Alexander; Hertwich, Edgar G.; Luderer, Gunnar

2017-12-01

Both fossil-fuel and non-fossil-fuel power technologies induce life-cycle greenhouse gas emissions, mainly due to their embodied energy requirements for construction and operation, and upstream CH4 emissions. Here, we integrate prospective life-cycle assessment with global integrated energy-economy-land-use-climate modelling to explore life-cycle emissions of future low-carbon power supply systems and implications for technology choice. Future per-unit life-cycle emissions differ substantially across technologies. For a climate protection scenario, we project life-cycle emissions from fossil fuel carbon capture and sequestration plants of 78-110 gCO2eq kWh-1, compared with 3.5-12 gCO2eq kWh-1 for nuclear, wind and solar power for 2050. Life-cycle emissions from hydropower and bioenergy are substantial (˜100 gCO2eq kWh-1), but highly uncertain. We find that cumulative emissions attributable to upscaling low-carbon power other than hydropower are small compared with direct sectoral fossil fuel emissions and the total carbon budget. Fully considering life-cycle greenhouse gas emissions has only modest effects on the scale and structure of power production in cost-optimal mitigation scenarios.

Economic evaluation of ticagrelor for secondary prevention following acute coronary syndromes.

PubMed

Gouveia, Miguel; Borges, Margarida; Trindade, Rosário; Rikner, Klas

2015-01-01

To estimate the cost-effectiveness and cost-utility of ticagrelor in the treatment of patients with acute coronary syndromes (unstable angina or myocardial infarction with or without ST-segment elevation), including patients treated medically and those undergoing percutaneous coronary intervention or coronary artery bypass grafting. A short-term decision tree and a long-term Markov model were used to simulate the evolution of patients' life-cycles. Clinical effectiveness data were collected from the PLATO trial and resource use data were obtained from the Hospital de Santa Marta database, disease-related group legislation and the literature. Ticagrelor provides increases of 0.1276 life years and 0.1106 quality-adjusted life years (QALYs) per patient. From a societal perspective these clinical gains entail an increase in expenditure of €610. Thus the incremental cost per life year saved is €4780 and the incremental cost per QALY is €5517. The simulation results show that ticagrelor reduces events compared to clopidogrel. The costs of ticagrelor are partially offset by lower costs arising from events prevented. The use of ticagrelor in clinical practice is therefore cost-effective compared to generic clopidogrel. Copyright © 2014 Sociedade Portuguesa de Cardiologia. Published by Elsevier España. All rights reserved.

Application of life cycle assessment for an evaluation of wastewater treatment and reuse project--case study of Xi'an, China.

PubMed

Zhang, Q H; Wang, X C; Xiong, J Q; Chen, R; Cao, B

2010-03-01

In order to illuminate the benefit of a wastewater treatment and reuse project, a life cycle assessment (LCA) model was proposed by combining the process-based LCA and the input-output based LCA in one framework and using energy consumption as the sole parameter for quantitative evaluation of the project. The life cycle consumption was evaluated mainly by life cycle inventory (LCI) analysis taking into account the construction phase, operation phase and demolishment phase of the project. For evaluating the life cycle benefit of treated water reuse, attention was paid to the decrease of secondary effluent discharge and water saving. As a result of comprehensive LCA analysis of a case project in Xi'an, China, it was understood that the life cycle benefit gained from treated wastewater reuse much surpassed the life cycle energy consumption. The advantage of wastewater treatment and reuse was well shown by LCA analysis using the proposed model. 2009 Elsevier Ltd. All rights reserved.

A case study by life cycle assessment

NASA Astrophysics Data System (ADS)

Li, Shuyun

2017-05-01

This article aims to assess the potential environmental impact of an electrical grinder during its life cycle. The Life Cycle Inventory Analysis was conducted based on the Simplified Life Cycle Assessment (SLCA) Drivers that calculated from the Valuation of Social Cost and Simplified Life Cycle Assessment Model (VSSM). The detailed results for LCI can be found under Appendix II. The Life Cycle Impact Assessment was performed based on Eco-indicator 99 method. The analysis results indicated that the major contributor to the environmental impact as it accounts for over 60% overall SLCA output. In which, 60% of the emission resulted from the logistic required for the maintenance activities. This was measured by conducting the hotspot analysis. After performing sensitivity analysis, it is evidenced that changing fuel type results in significant decrease environmental footprint. The environmental benefit can also be seen from the negative output values of the recycling activities. By conducting Life Cycle Assessment analysis, the potential environmental impact of the electrical grinder was investigated.

Basic life support: evaluation of learning using simulation and immediate feedback devices1.

PubMed

Tobase, Lucia; Peres, Heloisa Helena Ciqueto; Tomazini, Edenir Aparecida Sartorelli; Teodoro, Simone Valentim; Ramos, Meire Bruna; Polastri, Thatiane Facholi

2017-10-30

to evaluate students' learning in an online course on basic life support with immediate feedback devices, during a simulation of care during cardiorespiratory arrest. a quasi-experimental study, using a before-and-after design. An online course on basic life support was developed and administered to participants, as an educational intervention. Theoretical learning was evaluated by means of a pre- and post-test and, to verify the practice, simulation with immediate feedback devices was used. there were 62 participants, 87% female, 90% in the first and second year of college, with a mean age of 21.47 (standard deviation 2.39). With a 95% confidence level, the mean scores in the pre-test were 6.4 (standard deviation 1.61), and 9.3 in the post-test (standard deviation 0.82, p <0.001); in practice, 9.1 (standard deviation 0.95) with performance equivalent to basic cardiopulmonary resuscitation, according to the feedback device; 43.7 (standard deviation 26.86) mean duration of the compression cycle by second of 20.5 (standard deviation 9.47); number of compressions 167.2 (standard deviation 57.06); depth of compressions of 48.1 millimeter (standard deviation 10.49); volume of ventilation 742.7 (standard deviation 301.12); flow fraction percentage of 40.3 (standard deviation 10.03). the online course contributed to learning of basic life support. In view of the need for technological innovations in teaching and systematization of cardiopulmonary resuscitation, simulation and feedback devices are resources that favor learning and performance awareness in performing the maneuvers.

Hydrocarbon bio-jet fuel from bioconversion of poplar biomass: life cycle assessment.

PubMed

Budsberg, Erik; Crawford, Jordan T; Morgan, Hannah; Chin, Wei Shan; Bura, Renata; Gustafson, Rick

2016-01-01

Bio-jet fuels compatible with current aviation infrastructure are needed as an alternative to petroleum-based jet fuel to lower greenhouse gas emissions and reduce dependence on fossil fuels. Cradle to grave life cycle analysis is used to investigate the global warming potential and fossil fuel use of converting poplar biomass to drop-in bio-jet fuel via a novel bioconversion platform. Unique to the biorefinery designs in this research is an acetogen fermentation step. Following dilute acid pretreatment and enzymatic hydrolysis, poplar biomass is fermented to acetic acid and then distilled, hydroprocessed, and oligomerized to jet fuel. Natural gas steam reforming and lignin gasification are proposed to meet hydrogen demands at the biorefineries. Separate well to wake simulations are performed using the hydrogen production processes to obtain life cycle data. Both biorefinery designs are assessed using natural gas and hog fuel to meet excess heat demands. Global warming potential of the natural gas steam reforming and lignin gasification bio-jet fuel scenarios range from CO2 equivalences of 60 to 66 and 32 to 73 g MJ(-1), respectively. Fossil fuel usage of the natural gas steam reforming and lignin gasification bio-jet fuel scenarios range from 0.78 to 0.84 and 0.71 to 1.0 MJ MJ(-1), respectively. Lower values for each impact category result from using hog fuel to meet excess heat/steam demands. Higher values result from using natural gas to meet the excess heat demands. Bio-jet fuels produced from the bioconversion of poplar biomass reduce the global warming potential and fossil fuel use compared with petroleum-based jet fuel. Production of hydrogen is identified as a major source of greenhouse gas emissions and fossil fuel use in both the natural gas steam reforming and lignin gasification bio-jet simulations. Using hog fuel instead of natural gas to meet heat demands can help lower the global warming potential and fossil fuel use at the biorefineries.

The circle of life: A cross-cultural comparison of children's attribution of life-cycle traits.

PubMed

Burdett, Emily R R; Barrett, Justin L

2016-06-01

Do children attribute mortality and other life-cycle traits to all minded beings? The present study examined whether culture influences young children's ability to conceptualize and differentiate human beings from supernatural beings (such as God) in terms of life-cycle traits. Three-to-5-year-old Israeli and British children were questioned whether their mother, a friend, and God would be subject to various life-cycle processes: Birth, death, ageing, existence/longevity, and parentage. Children did not anthropomorphize but differentiated among human and supernatural beings, attributing life-cycle traits to humans, but not to God. Although 3-year-olds differentiated significantly among agents, 5-year-olds attributed correct life-cycle traits more consistently than younger children. The results also indicated some cross-cultural variation in these attributions. Implications for biological conceptual development are discussed. © 2015 The British Psychological Society.

Long life nickel electrodes for a nickel-hydrogen cell: Cycle life tests

NASA Technical Reports Server (NTRS)

Lim, H. S.; Verzwyvelt, S. A.

1985-01-01

In order to develop a long life nickel electrode for a Ni/H2 cell, the cycle life of nickel electrodes was tested in Ni/H2 boiler plate cells. A 19 test cell matrix was made of various nickel electrode designs including three levels each of plaque mechanical strength, median pore size of the plaque, and active material loading. Test cells were cycled to the end of their life (0.5v) in a 45 minute low Earth orbit cycle regime at 80% depth-of-discharge. It is shown that the active material loading level affects the cycle life the most with the optimum loading at 1.6 g/cc void. Mechanical strength does not affect the cycle life noticeably in the bend strength range of 400 to 700 psi. It is found that the best plaque is made of INCO nickel powder type 287 and has median pore size of 13 micron.

[Not Available].

PubMed

Pecevski, Dejan; Natschläger, Thomas; Schuch, Klaus

2009-01-01

The Parallel Circuit SIMulator (PCSIM) is a software package for simulation of neural circuits. It is primarily designed for distributed simulation of large scale networks of spiking point neurons. Although its computational core is written in C++, PCSIM's primary interface is implemented in the Python programming language, which is a powerful programming environment and allows the user to easily integrate the neural circuit simulator with data analysis and visualization tools to manage the full neural modeling life cycle. The main focus of this paper is to describe PCSIM's full integration into Python and the benefits thereof. In particular we will investigate how the automatically generated bidirectional interface and PCSIM's object-oriented modular framework enable the user to adopt a hybrid modeling approach: using and extending PCSIM's functionality either employing pure Python or C++ and thus combining the advantages of both worlds. Furthermore, we describe several supplementary PCSIM packages written in pure Python and tailored towards setting up and analyzing neural simulations.

Concentrated Electrolyte for the Sodium-Oxygen Battery: Solvation Structure and Improved Cycle Life.

PubMed

He, Mingfu; Lau, Kah Chun; Ren, Xiaodi; Xiao, Neng; McCulloch, William D; Curtiss, Larry A; Wu, Yiying

2016-12-05

Alkali metal-oxygen batteries are of great interests for energy storage because of their unparalleled theoretical energy densities. Particularly attractive is the emerging Na-O 2 battery because of the formation of superoxide as the discharge product. Dimethyl sulfoxide (DMSO) is a promising solvent for this battery but its instability towards Na makes it impractical in the Na-O 2 battery. Herein we report the enhanced stability of Na in DMSO solutions containing concentrated sodium trifluoromethanesulfonimide (NaTFSI) salts (>3 mol kg -1 ). Raman spectra of NaTFSI/DMSO electrolytes and ab initio molecular dynamics simulation reveal the Na + solvation number in DMSO and the formation of Na(DMSO) 3 (TFSI)-like solvation structure. The majority of DMSO molecules solvating Na + in concentrated solutions reduces the available free DMSO molecules that can react with Na and renders the TFSI anion decomposition, which protects Na from reacting with the electrolyte. Using these concentrated electrolytes, Na-O 2 batteries can be cycled forming sodium superoxide (NaO 2 ) as the sole discharge product with improved long cycle life, highlighting the beneficial role of concentrated electrolytes for Na-based batteries. © 2016 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Concentrated Electrolyte for the Sodium-Oxygen Battery: Solvation Structure and Improved Cycle Life

DOE PAGES

He, Mingfu; Lau, Kah Chun; Ren, Xiaodi; ...

2016-11-03

Alkali metal-oxygen batteries are of great interests for energy storage because of their unparalleled theoretical energy densities. Particularly attractive is the emerging Na-O 2 battery because of the formation of superoxide as the discharge product. Dimethyl sulfoxide (DMSO) is a promising solvent for this battery but its instability towards Na makes it impractical in the Na-O 2 battery. Here in this paper, we report the enhanced stability of Na in DMSO solutions containing concentrated sodium trifluoromethanesulfonimide (NaTFSI) salts (>3molkg -1). Raman spectra of NaTFSI/DMSO electrolytes and abinitio molecular dynamics simulation reveal the Na + solvation number in DMSO and themore » formation of Na(DMSO) 3(TFSI)-like solvation structure. The majority of DMSO molecules solvating Na + in concentrated solutions reduces the available free DMSO molecules that can react with Na and renders the TFSI anion decomposition, which protects Na from reacting with the electrolyte. Using these concentrated electrolytes, Na-O 2 batteries can be cycled forming sodium superoxide (NaO 2) as the sole discharge product with improved long cycle life, highlighting the beneficial role of concentrated electrolytes for Na-based batteries.« less

Penetration of hydrogen-based energy system and its potential for causing global environmental change: Scoping risk analysis based on life cycle thinking

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kikuchi, Ryunosuke

2006-03-15

A hydrogen-based economy seems superficially to be environmentally friendly, and many people have worked toward its realization. Today hydrogen is mainly produced by decarbonizing fossil fuels (e.g. natural gas), and in the future decarbonization of both fossil fuels and biomass will play a leading role in the production of hydrogen. The main purpose of this paper is to suggest the identification of potential environmental risks in terms of 'life cycle thinking' (which considers all aspects from production to utilization) with regard to the hydrogen-based economy to come. Hydrogen production by decarbonization results in CO{sub 2} emissions. The final destination ofmore » the recovered CO{sub 2} is uncertain. Furthermore, there is a possibility that hydrogen molecules will escape to the atmosphere, posing risks that could occasion global environmental changes such as depletion of stratospheric ozone, temperature change in the stratosphere and change of the hydrides cycle through global vaporization. Based on the results of simulation, requirements regarding the following items are proposed to minimize potential risks: hydrogen source, production and storage loss.« less

Increase Return on Investment of Software Development Life Cycle by Managing the Risk - A Case Study

DTIC Science & Technology

2015-04-01

for increasing the return on investment during the Software Development Life Cycle ( SDLC ) through selected quantitative analyses employing both the...defect rate, return on investment (ROI), software development life cycle ( SDLC ) DE FE N SE A C Q U IS IT IO N UN IVERSITY ALU M N I A SSO C IATIO N R...becomes comfortable due to its intricacies and learning cycle. The same may be said with respect to software development life cycle ( SDLC ) management

LIFE CYCLE ASSESSMENT FOR PC BLEND 2 AIRCRAFT RADOME DEPAINTER

EPA Science Inventory

This report describes the life cycle assessment on a potential replacement solvent blend for aircraft radome depainting at the Oklahoma City Air Logistics Center at Tinker Air Force Base. The life cycle assessment is composed of three separate but interrelated components: life cy...

A teleonomic model describing performance (body, milk and intake) during growth and over repeated reproductive cycles throughout the lifespan of dairy cattle. 1. Trajectories of life function priorities and genetic scaling.

PubMed

Martin, O; Sauvant, D

2010-12-01

The prediction of the control of nutrient partitioning, particularly energy, is a major issue in modelling dairy cattle performance. The proportions of energy channelled to physiological functions (growth, maintenance, gestation and lactation) change as the animal ages and reproduces, and according to its genotype and nutritional environment. This is the first of two papers describing a teleonomic model of individual performance during growth and over repeated reproductive cycles throughout the lifespan of dairy cattle. The conceptual framework is based on the coupling of a regulating sub-model providing teleonomic drives to govern the work of an operating sub-model scaled with genetic parameters. The regulating sub-model describes the dynamic partitioning of a mammal female's priority between life functions targeted to growth (G), ageing (A), balance of body reserves (R) and nutrient supply of the unborn (U), newborn (N) and suckling (S) calf. The so-called GARUNS dynamic pattern defines a trajectory of relative priorities, goal directed towards the survival of the individual for the continuation of the specie. The operating sub-model describes changes in body weight (BW) and composition, foetal growth, milk yield and composition and food intake in dairy cows throughout their lifespan, that is, during growth, over successive reproductive cycles and through ageing. This dynamic pattern of performance defines a reference trajectory of a cow under normal husbandry conditions and feed regimen. Genetic parameters are incorporated in the model to scale individual performance and simulate differences within and between breeds. The model was calibrated for dairy cows with literature data. The model was evaluated by comparison with simulations of previously published empirical equations of BW, body condition score, milk yield and composition and feed intake. This evaluation showed that the model adequately simulates these production variables throughout the lifespan, and across a range of dairy cattle genotypes.

Modeling greenhouse gas emissions from dairy farms.

PubMed

Rotz, C Alan

2017-11-15

Dairy farms have been identified as an important source of greenhouse gas emissions. Within the farm, important emissions include enteric CH 4 from the animals, CH 4 and N 2 O from manure in housing facilities during long-term storage and during field application, and N 2 O from nitrification and denitrification processes in the soil used to produce feed crops and pasture. Models using a wide range in level of detail have been developed to represent or predict these emissions. They include constant emission factors, variable process-related emission factors, empirical or statistical models, mechanistic process simulations, and life cycle assessment. To fully represent farm emissions, models representing the various emission sources must be integrated to capture the combined effects and interactions of all important components. Farm models have been developed using relationships across the full scale of detail, from constant emission factors to detailed mechanistic simulations. Simpler models, based upon emission factors and empirical relationships, tend to provide better tools for decision support, whereas more complex farm simulations provide better tools for research and education. To look beyond the farm boundaries, life cycle assessment provides an environmental accounting tool for quantifying and evaluating emissions over the full cycle, from producing the resources used on the farm through processing, distribution, consumption, and waste handling of the milk and dairy products produced. Models are useful for improving our understanding of farm processes and their interacting effects on greenhouse gas emissions. Through better understanding, they assist in the development and evaluation of mitigation strategies for reducing emissions and improving overall sustainability of dairy farms. The Authors. Published by the Federation of Animal Science Societies and Elsevier Inc. on behalf of the American Dairy Science Association®. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/3.0/).

INSTAR: simulating the biological cycle of a forest pest in Mediterranean pine stands

NASA Astrophysics Data System (ADS)

Suárez-Muñoz, María; Bonet García, Francisco J.; Hódar, José A.

2017-04-01

The pine processionary moth (Thaumetopoea pityocampa) is a typically Mediterranean forest pest feeding on pine needles during its larval stages. The outbreaks of this pest cause important landscape impacts and public health problems (i.e. larvae are very urticant). Larvae feed during winter months and cold temperature is the main limiting factor in their development. Therefore, rising temperatures are thought to benefit this species. Indeed, observations suggest that outbreaks are becoming more frequent and populations are shifting uphill. The objective of this work is to simulate the biological cycle of T. pityocampa to make predictions about where and when outbreaks will occur. Thus, we have created a model called INSTAR that will help to identify hotspots and foresee massive defoliation episodes. This will enhance the information available for the control of this pest. INSTAR is an Agent-Based Model, which allows the inclusion of important characteristics of the system: emergence, feedback (i.e. interaction between agents and their environment), adaptation (i.e. decision based on the mentioned interactions) and path dependence (i.e. possibilities at one time point are determined by past conditions). These characteristics arise from a set of functions simulating pine growth, processionary development, mortality and movement. These functions are easily extrapolable to other similar biological processes and therefore INSTAR aims at serving of example for other forest pest models. INSTAR is the first comprehensive approach to simulate the biological cycle of T pityocampa. It simulates the pest development in a given area, from which elevation and pine trees are considered. Moreover, it is also a good example of integrating environmental information into a population dynamic model: meteorological variables and soil moisture are obtained from a hydrological model (WiMMed, Herrero et al. 2009) executed for the area of interest. These variables are the inputs of the model, which feed the functions that simulate the processionary life cycle. Model's executions in two different areas and for relatively long time frames (1993-2014 and 2000-2014) yield relevant information about the biological cycle of the forest pest: the simulated peaks of larvae are followed by minimal values of pine biomass and pine infections are more abundant at the edge of the stands. Moreover, emerging patterns such as denso-dependency can be observed. To sum up, INSTAR is a promising tool for modeling T. pityocampa population dynamics. The obtained model will help to improve the decision making process regarding the control of the forest pest. Moreover, its simple structure of functions will facilitate the design of new models simulating other forest pests.

Thermomechanical Fatigue of Ductile Cast Iron and Its Life Prediction

NASA Astrophysics Data System (ADS)

Wu, Xijia; Quan, Guangchun; MacNeil, Ryan; Zhang, Zhong; Liu, Xiaoyang; Sloss, Clayton

2015-06-01

Thermomechanical fatigue (TMF) behaviors of ductile cast iron (DCI) were investigated under out-of-phase (OP), in-phase (IP), and constrained strain-control conditions with temperature hold in various temperature ranges: 573 K to 1073 K, 723 K to 1073 K, and 433 K to 873 K (300 °C to 800 °C, 450 °C to 800 °C, and 160 °C to 600 °C). The integrated creep-fatigue theory (ICFT) model was incorporated into the finite element method to simulate the hysteresis behavior and predict the TMF life of DCI under those test conditions. With the consideration of four deformation/damage mechanisms: (i) plasticity-induced fatigue, (ii) intergranular embrittlement, (iii) creep, and (iv) oxidation, as revealed from the previous study on low cycle fatigue of the material, the model delineates the contributions of these physical mechanisms in the asymmetrical hysteresis behavior and the damage accumulation process leading to final TMF failure. This study shows that the ICFT model can simulate the stress-strain response and life of DCI under complex TMF loading profiles (OP and IP, and constrained with temperature hold).

Nickel hydrogen low Earth orbit life testing

NASA Technical Reports Server (NTRS)

Badcock, C. C.; Haag, R. L.

1986-01-01

A program to demonstrate the long term reliability of NiH2 cells in low Earth orbits (LEO) and support use in mid-altitude orbits (MAO) was initiated. Both 3.5 and 4.5 inch diameter nickel hydrogen cells are included in the test plan. Cells from all U.S. vendors are to be tested. The tests will be performed at -5 and 10 C at 40 and 60% DOD for LEO orbit and 10 C and 80% DOD for MAO orbit simulations. The goals of the testing are 20,000 cycles at 60% DOD and 30,000 cycles at 40% DOD. Cells are presently undergoing acceptance and characterization testing at Naval Weapons Systems Center, Crane.

NREL: U.S. Life Cycle Inventory Database - Related Links

Science.gov Websites

) information, LCA tools, research institutes utilizing LCA, labeling initiatives and organizations , international LCA initiatives, LCA online forums. Life Cycle Inventory Data Ecoinvent: Swiss Centre for Life Institute for Environmental Research and Education): The American Center for Life Cycle Assessment SETAC

Optimal seasonal schedules and the relative dominance of heteromorphic and isomorphic life cycles in macroalgae.

PubMed

Bessho, Kazuhiro; Iwasa, Yoh

2010-11-21

Marine macroalgae (seaweed) show diverse life cycles. Species with a heteromorphic life cycle have a large multicellular algal body in one generation but have a very small body in the second generation of the same year. In contrast, the diploid and haploid life forms of isomorphic species have similar morphology, and these species often have more than two generations in a year. Here, we first study the optimal life cycle schedule of marine macroalgae when daily mortality changes seasonally, and then we discuss the conditions for coexistence and relative dominance of different life cycles. According to the optimal life cycle schedule, heteromorphic species tend to have a generation with a large algal body when mortality is low, and a microscopic-sized generation when mortality is high. In contrast, isomorphic species tend to mature when body size reaches a threshold value that is the same for different generations. We then examine the coexistence of the two life cycles when growth rate decreases with biomass. The model predicts that (1) at high latitudes (i.e., in strongly seasonal environments), heteromorphic species are likely to dominate over isomorphic species, and (2) species with a heteromorphic life cycle should dominate in the supratidal and upper intertidal zones where macroalgae tend to suffer high mortality, and also in the subtidal zone, where mortality is low, whereas isomorphic species are likely to be more successful when mortality is intermediate. These predictions are consistent with the observed distribution patterns of the two life cycles in macroalgae. Copyright © 2010 Elsevier Ltd. All rights reserved.

Crack initiation modeling of a directionally-solidified nickel-base superalloy

NASA Astrophysics Data System (ADS)

Gordon, Ali Page

Combustion gas turbine components designed for application in electric power generation equipment are subject to periodic replacement as a result of cracking, damage, and mechanical property degeneration that render them unsafe for continued operation. In view of the significant costs associated with inspecting, servicing, and replacing damaged components, there has been much interest in developing models that not only predict service life, but also estimate the evolved microstructural state of the material. This thesis explains manifestations of microstructural damage mechanisms that facilitate fatigue crack nucleation in a newly-developed directionally-solidified (DS) Ni-base superalloy components exposed to elevated temperatures and high stresses. In this study, models were developed and validated for damage and life prediction using DS GTD-111 as the subject material. This material, proprietary to General Electric Energy, has a chemical composition and grain structure designed to withstand creep damage occurring in the first and second stage blades of gas-powered turbines. The service conditions in these components, which generally exceed 600°C, facilitate the onset of one or more damage mechanisms related to fatigue, creep, or environment. The study was divided into an empirical phase, which consisted of experimentally simulating service conditions in fatigue specimens, and a modeling phase, which entailed numerically simulating the stress-strain response of the material. Experiments have been carried out to simulate a variety of thermal, mechanical, and environmental operating conditions endured by longitudinally (L) and transversely (T) oriented DS GTD-111. Both in-phase and out-of-phase thermo-mechanical fatigue tests were conducted. In some cases, tests in extreme environments/temperatures were needed to isolate one or at most two of the mechanisms causing damage. Microstructural examinations were carried out via SEM and optical microscopy. A continuum crystal plasticity model was used to simulate the material behavior in the L and T orientations. The constitutive model was implemented in ABAQUS and a parameter estimation scheme was developed to obtain the material constants. A physically-based model was developed for correlating crack initiation life based on the experimental life data and predictions are made using the crack initiation model. Assuming a unique relationship between the damage fraction and cycle fraction with respect to cycles to crack initiation for each damage mode, the total crack initiation life has been represented in terms of the individual damage components (fatigue, creep-fatigue, creep, and oxidation-fatigue) observed at the end state of crack initiation.

Intensification of convective extremes driven by cloud-cloud interaction

NASA Astrophysics Data System (ADS)

Moseley, Christopher; Hohenegger, Cathy; Berg, Peter; Haerter, Jan O.

2016-10-01

In a changing climate, a key role may be played by the response of convective-type cloud and precipitation to temperature changes. Yet, it is unclear if convective precipitation intensities will increase mainly due to thermodynamic or dynamical processes. Here we perform large eddy simulations of convection by imposing a realistic diurnal cycle of surface temperature. We find convective events to gradually self-organize into larger cloud clusters and those events occurring late in the day to produce the highest precipitation intensities. Tracking rain cells throughout their life cycles, we show that events which result from collisions respond strongly to changes in boundary conditions, such as temperature changes. Conversely, events not resulting from collisions remain largely unaffected by the boundary conditions. Increased surface temperature indeed leads to more interaction between events and stronger precipitation extremes. However, comparable intensification occurs when leaving temperature unchanged but simply granting more time for self-organization. These findings imply that the convective field as a whole acquires a memory of past precipitation and inter-cloud dynamics, driving extremes. For global climate model projections, our results suggest that the interaction between convective clouds must be incorporated to simulate convective extremes and the diurnal cycle more realistically.

[Life cycle assessment of energy consumption and greenhouse gas emissions of cellulosic ethanol from corn stover].

PubMed

Tian, Wang; Liao, Cuiping; Li, Li; Zhao, Daiqing

2011-03-01

Life Cycle Assessment (LCA) is the only standardized tool currently used to assess environmental loads of products and processes. The life cycle analysis, as a part of LCA, is a useful and powerful methodology for studying life cycle energy efficiency and life cycle GHG emission. To quantitatively explain the potential of energy saving and greenhouse gas (GHG) emissions reduction of corn stover-based ethanol, we analyzed life cycle energy consumption and GHG emissions of corn stover-based ethanol by the method of life cycle analysis. The processes are dilute acid prehydrolysis and enzymatic hydrolysis. The functional unit was defined as 1 km distance driven by the vehicle. Results indicated: compared with gasoline, the corn stover-based E100 (100% ethanol) and E10 (a blend of 10% ethanol and 90% gasoline by volume) could reduce life cycle fossil energy consumption by 79.63% and 6.25% respectively, as well as GHG emissions by 53.98% and 6.69%; the fossil energy consumed by biomass stage was 68.3% of total fossil energy input, N-fertilizer and diesel were the main factors which contributed 45.78% and 33.26% to biomass stage; electricity production process contributed 42.06% to the net GHG emissions, the improvement of technology might reduce emissions markedly.

Life cycle energy and greenhouse gas emission effects of biodiesel in the United States with induced land use change impacts

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chen, Rui; Qin, Zhangcai; Han, Jeongwoo

This study conducted the updated simulations to depict a life cycle analysis (LCA) of the biodiesel production from soybeans and other feedstocks in the U.S. It addressed in details the interaction between LCA and induced land use change (ILUC) for biodiesel. Relative to the conventional petroleum diesel, soy biodiesel could achieve 76% reduction in GHG emissions without considering ILUC, or 66-72% reduction in overall GHG emissions when various ILUC cases were considered. Soy biodiesel’s fossil fuel consumption rate was also 80% lower than its petroleum counterpart. Furthermore, this study examined the cause and the implication of each key parameter affectingmore » biodiesel LCA results using a sensitivity analysis, which identified the hot spots for fossil fuel consumption and GHG emissions of biodiesel so that future efforts can be made accordingly. Finally, biodiesel produced from other feedstocks (canola oil and tallow) were also investigated to contrast with soy biodiesel and petroleum diesel« less

Influence of System Operation Method on CO2 Emissions of PV/Solar Heat/Cogeneration System

NASA Astrophysics Data System (ADS)

Oke, Shinichiro; Kemmoku, Yoshishige; Takikawa, Hirofumi; Sakakibara, Tateki

A PV/solar heat/cogeneration system is assumed to be installed in a hotel. The system is operated with various operation methods: CO2 minimum operation, fees minimum operation, seasonal operation, daytime operation and heat demand following operation. Of these five operations, the former two are virtual operations that are operated with the dynamic programming method, and the latter three are actual operations. Computer simulation is implemented using hourly data of solar radiation intensity, atmospheric temperature, electric, cooling, heating and hot water supply demands for one year, and the life-cycle CO2 emission and the total cost are calculated for every operations. The calculation results show that the virtual two and the actual three operations reduce the life-cycle CO2 emission by 21% and 13% compared with the conventional system, respectively. In regard to both the CO2 emission and the cost, there is no significant difference between the virtual two operation methods or among actual three operation methods.

Potential for Integrating Diffusion of Innovation Principles into Life Cycle Assessment of Emerging Technologies.

PubMed

Sharp, Benjamin E; Miller, Shelie A

2016-03-15

Life cycle assessment (LCA) measures cradle-to-grave environmental impacts of a product. To assess impacts of an emerging technology, LCA should be coupled with additional methods that estimate how that technology might be deployed. The extent and manner that an emerging technology diffuses throughout a region shapes the magnitude and type of environmental impacts. Diffusion of innovation is an established field of research that analyzes the adoption of new innovations, and its principles can be used to construct scenario models that enhance LCA of emerging technologies. Integrating diffusion modeling techniques with an LCA of emerging technology can provide estimates for the extent of market penetration, the displacement of existing systems, and the rate of adoption. Two general perspectives of application are macro-level diffusion models that use a function of time to represent adoption, and microlevel diffusion models that simulate adoption through interactions of individuals. Incorporating diffusion of innovation concepts complement existing methods within LCA to inform proactive environmental management of emerging technologies.

The growth pattern and fuel life cycle analysis of the electricity consumption of Hong Kong.

PubMed

To, W M; Lai, T M; Lo, W C; Lam, K H; Chung, W L

2012-06-01

As the consumption of electricity increases, air pollutants from power generation increase. In metropolitans such as Hong Kong and other Asian cities, the surge of electricity consumption has been phenomenal over the past decades. This paper presents a historical review about electricity consumption, population, and change in economic structure in Hong Kong. It is hypothesized that the growth of electricity consumption and change in gross domestic product can be modeled by 4-parameter logistic functions. The accuracy of the functions was assessed by Pearson's correlation coefficient, mean absolute percent error, and root mean squared percent error. The paper also applies the life cycle approach to determine carbon dioxide, methane, nitrous oxide, sulfur dioxide, and nitrogen oxide emissions for the electricity consumption of Hong Kong. Monte Carlo simulations were applied to determine the confidence intervals of pollutant emissions. The implications of importing more nuclear power are discussed. Copyright © 2012 Elsevier Ltd. All rights reserved.

Simulation of cracking cores when molding piston components

NASA Astrophysics Data System (ADS)

Petrenko, Alena; Soukup, Josef

2014-08-01

The article deals with pistons casting made from aluminum alloy. Pistons are casting at steel mold with steel core. The casting is provided by gravity casting machine. The each machine is equipped by two metal molds, which are preheated above temperature 160 °C before use. The steel core is also preheated by flame. The metal molds and cores are heated up within the casting process. The temperature of the metal mold raise up to 200 °C and temperature of core is higher. The surface of the core is treated by nitration. The mold and core are cooled down by water during casting process. The core is overheated and its top part is finally cracked despite its intensive water-cooling. The life time cycle of the core is decreased to approximately 5 to 15 thousands casting, which is only 15 % of life time cycle of core for production of other pistons. The article presents the temperature analysis of the core.

Parametric sensitivity study for solar-assisted heat-pump systems

NASA Astrophysics Data System (ADS)

White, N. M.; Morehouse, J. H.

1981-07-01

The engineering and economic parameters affecting life-cycle costs for solar-assisted heat pump systems are investigted. The change in energy usage resulting from each engineering parameter varied was developed from computer simulations, and is compared with results from a stand-alone heat pump system. Three geographical locations are considered: Washington, DC, Fort Worth, TX, and Madison, WI. Results indicate that most engineering changes to the systems studied do not provide significant energy savings. The most promising parameters to ary are the solar collector parameters tau (-) and U/sub L/ the heat pump capacity at design point, and the minimum utilizable evaporator temperature. Costs associated with each change are estimated, and life-cycle costs computed for both engineering parameters and economic variations in interest rate, discount rate, tax credits, fuel unit costs and fuel inflation rates. Results indicate that none of the feasibile engineering changes for the system configuration studied will make these systems economically competitive with the stand-alone heat pump without a considerable tax credit.

Bayesian assurance and sample size determination in the process validation life-cycle.

PubMed

Faya, Paul; Seaman, John W; Stamey, James D

2017-01-01

Validation of pharmaceutical manufacturing processes is a regulatory requirement and plays a key role in the assurance of drug quality, safety, and efficacy. The FDA guidance on process validation recommends a life-cycle approach which involves process design, qualification, and verification. The European Medicines Agency makes similar recommendations. The main purpose of process validation is to establish scientific evidence that a process is capable of consistently delivering a quality product. A major challenge faced by manufacturers is the determination of the number of batches to be used for the qualification stage. In this article, we present a Bayesian assurance and sample size determination approach where prior process knowledge and data are used to determine the number of batches. An example is presented in which potency uniformity data is evaluated using a process capability metric. By using the posterior predictive distribution, we simulate qualification data and make a decision on the number of batches required for a desired level of assurance.

Assessment of Carrying Capacity of Timber Element Using SBRA Method

NASA Astrophysics Data System (ADS)

Kraus, Michal

2017-10-01

Wood as a building material has a significant perspective in the context of nonrenewable energy sources and production of greenhouse gas emissions. The subject of this paper is to verify the carrying capacity of the timber element using the probabilistic method Simulation Based Reliability Assessment (SBRA). The simulation is performed for one million cycles. Key factors decreasing the strength of wooden material at the time include the duration of the loads, and combinations thereof. Inconsiderable factor affecting the strength of wood is also the humidity. Continuous beam with three fields (length 15 m, glued laminated timber, and strength class GL 36 according to the DIN EN 1194) is placed in an environment with a thermal-humidity regime of the 2nd class according to the EC 5. Average life of carrying timber structure is estimated to be 50 years. The simulation results show that there is no risk of failure of wood during the first year. The probability of failure is common in the 10 years of its life. Then, wooden element already meets only a reduced level of reliability.

KOH concentration effect on the cycle life of nickel-hydrogen cells

NASA Technical Reports Server (NTRS)

Lim, H. S.; Verzwyvelt, S. A.

1985-01-01

Effects of KOH concentration on the cycle life of a sintered-type nickel electrode were studied in a boiler plate nickel-hydrogen cell at 23 C using an accelerated 45-min cycle regime at 80 percent depth of discharge. The cycle life improved greatly as the KOH concentration decreased, although the initial capacity of the cell decreased slightly. The cycle life improved by a factor of two or more when the KOH concentration was reduced from 36 to 31 percent and by a similar factor from reductions of 31 to 26 percent. For many applications, this life improvement may outweigh the initial capacity decrease.

The life cycles of Be viscous decretion discs: The case of ω CMa

NASA Astrophysics Data System (ADS)

Ghoreyshi, M. R.; Carciofi, A. C.; Rímulo, L. R.; Vieira, R. G.; Faes, D. M.; Baade, D.; Bjorkman, J. E.; Otero, S.; Rivinius, Th

2018-06-01

We analyzed V-band photometry of the Be star ω CMa, obtained during the last four decades, during which the star went through four complete cycles of disc formation and dissipation. The data were simulated by hydrodynamic models based on a time-dependent implementation of the viscous decretion disc (VDD) paradigm, in which a disc around a fast-spinning Be star is formed by material ejected by the star and driven to progressively larger orbits by means of viscous torques. Our simulations offer a good description of the photometric variability during phases of disc formation and dissipation, which suggests that the VDD model adequately describes the structural evolution of the disc. Furthermore, our analysis allowed us to determine the viscosity parameter α, as well as the net mass and angular momentum (AM) loss rates. We find that α is variable, ranging from 0.1 to 1.0, not only from cycle to cycle but also within a given cycle. Additionally, build-up phases usually have larger values of α than the dissipation phases. Furthermore, during dissipation the outward AM flux is not necessarily zero, meaning that ω CMa does not experience a true quiescence but, instead, switches between a high to a low AM loss rate during which the disc quickly assumes an overall lower density but never zero. We confront the average AM loss rate with predictions from stellar evolution models for fast-rotating stars, and find that our measurements are smaller by more than one order of magnitude.

Effect of LEO cycling on 125 Ah advanced design IPV nickel-hydrogen flight cells - An update

NASA Technical Reports Server (NTRS)

Smithrick, John J.; Hall, Stephen W.

1991-01-01

An update of validation test results confirming the breakthrough in LEO cycle life of nickel-hydrogen cells containing 26 percent potassium hydroxide (KOH) electrolyte is presented. A breakthrough in the LEO cycle life of individual pressure vessel nickel-hydrogen cells is reported. The cycle life of boiler plate cells containing 26 percent KOH electrolyte was about 40,000 LEO cycles compared to 3500 cycles for cells containing 31 percent KOH.

Control of flea populations in a simulated home environment model using lufenuron, imidacloprid or fipronil.

PubMed

Jacobs, D E; Hutchinson, M J; Ryan, W G

2001-03-01

Control strategies were evaluated over a 6-month period in a home simulation model comprising a series of similar carpeted pens, housing matched groups of six cats, in which the life-cycle of the flea Ctenocephalides felis felis Bouche (Siphonaptera: Pulicidae) had been established. Additional adult fleas were placed on the cats at intervals to mimic acquisition of extraneous fleas from outside the home. Treatment strategies included a single subcutaneous deposition of injectable lufenuron supported by initial treatments with a short-acting insecticidal spray, or monthly topical applications of imidacloprid or fipronil. An untreated control group indicated that conditions were suitable for flea replication and development. Controls had to be combed on 18 occasions to remove excessive flea burdens and two developed allergic reactions. Lufenuron cats were combed once and required two insecticidal treatments in the first month to achieve control. Even so, small flea burdens were constantly present thereafter. Imidacloprid and fipronil treatments appeared to give virtually complete control throughout. Single fleas were found on imidacloprid cats on two occasions, whereas none were recovered from fipronil cats at any time after the first treatment. Tracer cats were used to monitor re-infestation rates at the end of the trial period. Small numbers of host-seeking fleas were demonstrated in all treatment pens, indicating that total eradication had not been accomplished. It is concluded that the home environment simulation model incorporating tracer animals could provide a powerful tool for studying flea population dynamics under controlled conditions but improved techniques are needed for quantifying other off-host life-cycle stages.

The Role of Computational Modeling and Simulation in the Total Product Life Cycle of Peripheral Vascular Devices

PubMed Central

Morrison, Tina M.; Dreher, Maureen L.; Nagaraja, Srinidhi; Angelone, Leonardo M.; Kainz, Wolfgang

2018-01-01

The total product life cycle (TPLC) of medical devices has been defined by four stages: discovery and ideation, regulatory decision, product launch, and postmarket monitoring. Manufacturers of medical devices intended for use in the peripheral vasculature, such as stents, inferior vena cava (IVC) filters, and stent-grafts, mainly use computational modeling and simulation (CM&S) to aid device development and design optimization, supplement bench testing for regulatory decisions, and assess postmarket changes or failures. For example, computational solid mechanics and fluid dynamics enable the investigation of design limitations in the ideation stage. To supplement bench data in regulatory submissions, manufactures can evaluate the effects of anatomical characteristics and expected in vivo loading environment on device performance. Manufacturers might also harness CM&S to aid root-cause analyses that are necessary when failures occur postmarket, when the device is exposed to broad clinical use. Once identified, CM&S tools can then be used for redesign to address the failure mode and re-establish the performance profile with the appropriate models. The Center for Devices and Radiological Health (CDRH) wants to advance the use of CM&S for medical devices and supports the development of virtual physiological patients, clinical trial simulations, and personalized medicine. Thus, the purpose of this paper is to describe specific examples of how CM&S is currently used to support regulatory submissions at different phases of the TPLC and to present some of the stakeholder-led initiatives for advancing CM&S for regulatory decision-making. PMID:29479395

The Role of Computational Modeling and Simulation in the Total Product Life Cycle of Peripheral Vascular Devices.

PubMed

Morrison, Tina M; Dreher, Maureen L; Nagaraja, Srinidhi; Angelone, Leonardo M; Kainz, Wolfgang

2017-01-01

The total product life cycle (TPLC) of medical devices has been defined by four stages: discovery and ideation, regulatory decision, product launch, and postmarket monitoring. Manufacturers of medical devices intended for use in the peripheral vasculature, such as stents, inferior vena cava (IVC) filters, and stent-grafts, mainly use computational modeling and simulation (CM&S) to aid device development and design optimization, supplement bench testing for regulatory decisions, and assess postmarket changes or failures. For example, computational solid mechanics and fluid dynamics enable the investigation of design limitations in the ideation stage. To supplement bench data in regulatory submissions, manufactures can evaluate the effects of anatomical characteristics and expected in vivo loading environment on device performance. Manufacturers might also harness CM&S to aid root-cause analyses that are necessary when failures occur postmarket, when the device is exposed to broad clinical use. Once identified, CM&S tools can then be used for redesign to address the failure mode and re-establish the performance profile with the appropriate models. The Center for Devices and Radiological Health (CDRH) wants to advance the use of CM&S for medical devices and supports the development of virtual physiological patients, clinical trial simulations, and personalized medicine. Thus, the purpose of this paper is to describe specific examples of how CM&S is currently used to support regulatory submissions at different phases of the TPLC and to present some of the stakeholder-led initiatives for advancing CM&S for regulatory decision-making.

Current-induced transition from particle-by-particle to concurrent intercalation in phase-separating battery electrodes.

PubMed

Li, Yiyang; El Gabaly, Farid; Ferguson, Todd R; Smith, Raymond B; Bartelt, Norman C; Sugar, Joshua D; Fenton, Kyle R; Cogswell, Daniel A; Kilcoyne, A L David; Tyliszczak, Tolek; Bazant, Martin Z; Chueh, William C

2014-12-01

Many battery electrodes contain ensembles of nanoparticles that phase-separate on (de)intercalation. In such electrodes, the fraction of actively intercalating particles directly impacts cycle life: a vanishing population concentrates the current in a small number of particles, leading to current hotspots. Reports of the active particle population in the phase-separating electrode lithium iron phosphate (LiFePO4; LFP) vary widely, ranging from near 0% (particle-by-particle) to 100% (concurrent intercalation). Using synchrotron-based X-ray microscopy, we probed the individual state-of-charge for over 3,000 LFP particles. We observed that the active population depends strongly on the cycling current, exhibiting particle-by-particle-like behaviour at low rates and increasingly concurrent behaviour at high rates, consistent with our phase-field porous electrode simulations. Contrary to intuition, the current density, or current per active internal surface area, is nearly invariant with the global electrode cycling rate. Rather, the electrode accommodates higher current by increasing the active particle population. This behaviour results from thermodynamic transformation barriers in LFP, and such a phenomenon probably extends to other phase-separating battery materials. We propose that modifying the transformation barrier and exchange current density can increase the active population and thus the current homogeneity. This could introduce new paradigms to enhance the cycle life of phase-separating battery electrodes.

Environmental Impact of Buildings--What Matters?

PubMed

Heeren, Niko; Mutel, Christopher L; Steubing, Bernhard; Ostermeyer, York; Wallbaum, Holger; Hellweg, Stefanie

2015-08-18

The goal of this study was to identify drivers of environmental impact and quantify their influence on the environmental performance of wooden and massive residential and office buildings. We performed a life cycle assessment and used thermal simulation to quantify operational energy demand and to account for differences in thermal inertia of building mass. Twenty-eight input parameters, affecting operation, design, material, and exogenic building properties were sampled in a Monte Carlo analysis. To determine sensitivity, we calculated the correlation between each parameter and the resulting life cycle inventory and impact assessment scores. Parameters affecting operational energy demand and energy conversion are the most influential for the building's total environmental performance. For climate change, electricity mix, ventilation rate, heating system, and construction material rank the highest. Thermal inertia results in an average 2-6% difference in heat demand. Nonrenewable cumulative energy demand of wooden buildings is 18% lower, compared to a massive variant. Total cumulative energy demand is comparable. The median climate change impact is 25% lower, including end-of-life material credits and 22% lower, when credits are excluded. The findings are valid for small offices and residential buildings in Switzerland and regions with similar building culture, construction material production, and climate.

Evaluation of life-cycle air emission factors of freight transportation.

PubMed

Facanha, Cristiano; Horvath, Arpad

2007-10-15

Life-cycle air emission factors associated with road, rail, and air transportation of freight in the United States are analyzed. All life-cycle phases of vehicles, infrastructure, and fuels are accounted for in a hybrid life-cycle assessment (LCA). It includes not only fuel combustion, but also emissions from vehicle manufacturing, maintenance, and end of life, infrastructure construction, operation, maintenance, and end of life, and petroleum exploration, refining, and fuel distribution. Results indicate that total life-cycle emissions of freight transportation modes are underestimated if only tailpipe emissions are accounted for. In the case of CO2 and NOx, tailpipe emissions underestimate total emissions by up to 38%, depending on the mode. Total life-cycle emissions of CO and SO2 are up to seven times higher than tailpipe emissions. Sensitivity analysis considers the effects of vehicle type, geography, and mode efficiency on the final results. Policy implications of this analysis are also discussed. For example, while it is widely assumed that currently proposed regulations will result in substantial reductions in emissions, we find that this is true for NOx, emissions, because fuel combustion is the main cause, and to a lesser extent for SO2, but not for PM10 emissions, which are significantly affected by the other life-cycle phases.

Mass exchange in an experimental new-generation life support system model based on biological regeneration of environment.

PubMed

Tikhomirov, A A; Ushakova, S A; Manukovsky, N S; Lisovsky, G M; Kudenko, Yu A; Kovalev, V S; Gubanov, V G; Barkhatov, Yu V; Gribovskaya, I V; Zolotukhin, I G; Gros, J B; Lasseur, Ch

2003-01-01

An experimental model of a biological life support system was used to evaluate qualitative and quantitative parameters of the internal mass exchange. The photosynthesizing unit included the higher plant component (wheat and radish), and the heterotrophic unit consisted of a soil-like substrate, California worms, mushrooms and microbial microflora. The gas mass exchange involved evolution of oxygen by the photosynthesizing component and its uptake by the heterotroph component along with the formation and maintaining of the SLS structure, growth of mushrooms and California worms, human respiration, and some other processes. Human presence in the system in the form of "virtual human" that at regular intervals took part in the respirative gas exchange during the experiment. Experimental data demonstrated good oxygen/carbon dioxide balance, and the closure of the cycles of these gases was almost complete. The water cycle was nearly 100% closed. The main components in the water mass exchange were transpiration water and the watering solution with mineral elements. Human consumption of the edible plant biomass (grains and roots) was simulated by processing these products by a unique physicochemical method of oxidizing them to inorganic mineral compounds, which were then returned into the system and fully assimilated by the plants. The oxidation was achieved by "wet combustion" of organic biomass, using hydrogen peroxide following a special procedure, which does not require high temperature and pressure. Hydrogen peroxide is produced from the water inside the system. The closure of the cycle was estimated for individual elements and compounds. Stoichiometric proportions are given for the main components included in the experimental model of the system. Approaches to the mathematical modeling of the cycling processes are discussed, using the data of the experimental model. Nitrogen, as a representative of biogenic elements, shows an almost 100% closure of the cycle inside the system. The proposed experimental model of a biological system is discussed as a candidate for potential application in the investigations aimed at creating ecosystems with largely closed cycles of the internal mass exchange. The formation and maintenance of sustainable cycling of vitally important chemical elements and compounds in biological life support systems (BLSS) is an extremely pressing problem. To attain the stable functioning of biological life support systems (BLSS) and to maintain a high degree of closure of material cycles in than, it is essential to understand the character of mass exchange processes and stoichiometnc proportions of the initial and synthesized components of the system. c2003 COSPAR. Published by Elsevier Science Ltd. All rights reserved.

Comparative Life Cycle Assessment between Warm SMA and Conventional SMA

DOT National Transportation Integrated Search

2011-09-01

This report presents the comparative life cycle assessment (LCA) between warm stone mastic asphalt (SMA) and conventional : SMA. Specifically, the study evaluated and compared the life cycle environmental and economic performances of two mixtures: a ...

Geothermal Water Use: Life Cycle Water Consumption, Water Resource Assessment, and Water Policy Framework

DOE Data Explorer

Schroeder, Jenna N.

2014-06-10

This report examines life cycle water consumption for various geothermal technologies to better understand factors that affect water consumption across the life cycle (e.g., power plant cooling, belowground fluid losses) and to assess the potential water challenges that future geothermal power generation projects may face. Previous reports in this series quantified the life cycle freshwater requirements of geothermal power-generating systems, explored operational and environmental concerns related to the geochemical composition of geothermal fluids, and assessed future water demand by geothermal power plants according to growth projections for the industry. This report seeks to extend those analyses by including EGS flash, both as part of the life cycle analysis and water resource assessment. A regional water resource assessment based upon the life cycle results is also presented. Finally, the legal framework of water with respect to geothermal resources in the states with active geothermal development is also analyzed.

NASA welding assessment program

NASA Technical Reports Server (NTRS)

Patterson, R. E.

1985-01-01

A program was conducted to demonstrate the cycle life capability of welded solar cell modules relative to a soldered solar cell module in a simulated low earth orbit thermal environment. A total of five 18-cell welded (parallel gap resistance welding) modules, three 18-cell soldered modules, and eighteen single cell samples were fabricated using 2 x 4 cm silicon solar cells from ASEC, fused silica cover glass from OCLI, silver plated Invar interconnectors, DC 93-500 adhesive, and Kapton-Kevlar-Kapton flexible substrate material. Zero degree pull strength ranged from 2.4 to 5.7 lbs for front welded contacts (40 samples), and 3.5 to 6.2 lbs for back welded contacts (40 samples). Solar cell cross sections show solid state welding on both front and rear contacts. The 18-cell welded modules have a specific power of 124 W/kg and an area power density of 142 W/sq m (both at 28 C). Three welded and one soldered module were thermal cycle tested in a thermal vacuum chamber simulating a low earth orbit thermal environment.

Estimating the thickness of diffusive solid electrolyte interface

NASA Astrophysics Data System (ADS)

Wang, XiaoHe; Shen, WenHao; Huang, XianFu; Zang, JinLiang; Zhao, YaPu

2017-06-01

The solid electrolyte interface (SEI) is a hierarchical structure formed in the transition zone between the electrode and the electrolyte. The properties of lithium-ion (Li-ion) battery, such as cycle life, irreversible capacity loss, self-discharge rate, electrode corrosion and safety are usually ascribed to the quality of the SEI, which are highly dependent on the thickness. Thus, understanding the formation mechanism and the SEI thickness is of prime interest. First, we apply dimensional analysis to obtain an explicit relation between the thickness and the number density in this study. Then the SEI thickness in the initial charge-discharge cycle is analyzed and estimated for the first time using the Cahn-Hilliard phase-field model. In addition, the SEI thickness by molecular dynamics simulation validates the theoretical results. It has been shown that the established model and the simulation in this paper estimate the SEI thickness concisely within order-of-magnitude of nanometers. Our results may help in evaluating the performance of SEI and assist the future design of Li-ion battery.

Long Life Nickel Electrodes for a Nickel-hydrogen Cell: Cycle Life Tests

NASA Technical Reports Server (NTRS)

Lim, H. S.; Verzwyvelt, S. A.

1984-01-01

In order to develop a long life nickel electrode for a Ni/H2 cell, cycle life tests of nickel electrodes were carried out in Hi/H2 boiler plate cells. A 19 test cell matrix was made of various nickel electrode designs including three levels each of plaque mechanical strength, median pore size of the plaque, and active material loading. Test cells were cycled to the end of their life (0.5v) in a 45-minute low earth orbit cycle regime at 80% depth-of-discharge. The results show that the active material loading level affects the cycle life the most with the optimum loading at 1.6 g/cc void. Mechanical strength did not affect the cycle life noticeably in the bend strength range of 400 to 700 psi. The best plaque type appears to be one which is made of INCO nickel powder type 287 and has a median pore size of 13 micron.

Fitness and Individuality in Complex Life Cycles.

PubMed

Herron, Matthew D

2016-12-01

Complex life cycles are common in the eukaryotic world, and they complicate the question of how to define individuality. Using a bottom-up, gene-centric approach, I consider the concept of fitness in the context of complex life cycles. I analyze the fitness effects of an allele (or a trait) on different biological units within a complex life history and how these effects drive evolutionary change within populations. Based on these effects, I attempt to construct a concept of fitness that accurately predicts evolutionary change in the context of complex life cycles.

A comparative study of commercial lithium ion battery cycle life in electric vehicle: Capacity loss estimation

NASA Astrophysics Data System (ADS)

Han, Xuebing; Ouyang, Minggao; Lu, Languang; Li, Jianqiu

2014-12-01

Now the lithium ion batteries are widely used in electric vehicles (EV). The cycle life is among the most important characteristics of the power battery in EV. In this report, the battery cycle life experiment is designed according to the actual working condition in EV. Five different commercial lithium ion cells are cycled alternatively under 45 °C and 5 °C and the test results are compared. Based on the cycle life experiment results and the identified battery aging mechanism, the battery cycle life models are built and fitted by the genetic algorithm. The capacity loss follows a power law relation with the cycle times and an Arrhenius law relation with the temperature. For automotive application, to save the cost and the testing time, a battery SOH (state of health) estimation method combined the on-line model based capacity estimation and regular calibration is proposed.

A Growth Model for Academic Program Life Cycle (APLC): A Theoretical and Empirical Analysis

ERIC Educational Resources Information Center

Acquah, Edward H. K.

2010-01-01

Academic program life cycle concept states each program's life flows through several stages: introduction, growth, maturity, and decline. A mixed-influence diffusion growth model is fitted to enrolment data on academic programs to analyze the factors determining progress of academic programs through their life cycles. The regression analysis yield…

Parallel Multi-cycle LES of an Optical Pent-roof DISI Engine Under Motored Operating Conditions

DOE Office of Scientific and Technical Information (OSTI.GOV)

Van Dam, Noah; Sjöberg, Magnus; Zeng, Wei

The use of Large-eddy Simulations (LES) has increased due to their ability to resolve the turbulent fluctuations of engine flows and capture the resulting cycle-to-cycle variability. One drawback of LES, however, is the requirement to run multiple engine cycles to obtain the necessary cycle statistics for full validation. The standard method to obtain the cycles by running a single simulation through many engine cycles sequentially can take a long time to complete. Recently, a new strategy has been proposed by our research group to reduce the amount of time necessary to simulate the many engine cycles by running individual enginemore » cycle simulations in parallel. With modern large computing systems this has the potential to reduce the amount of time necessary for a full set of simulated engine cycles to finish by up to an order of magnitude. In this paper, the Parallel Perturbation Methodology (PPM) is used to simulate up to 35 engine cycles of an optically accessible, pent-roof Directinjection Spark-ignition (DISI) engine at two different motored engine operating conditions, one throttled and one un-throttled. Comparisons are made against corresponding sequential-cycle simulations to verify the similarity of results using either methodology. Mean results from the PPM approach are very similar to sequential-cycle results with less than 0.5% difference in pressure and a magnitude structure index (MSI) of 0.95. Differences in cycle-to-cycle variability (CCV) predictions are larger, but close to the statistical uncertainty in the measurement for the number of cycles simulated. PPM LES results were also compared against experimental data. Mean quantities such as pressure or mean velocities were typically matched to within 5- 10%. Pressure CCVs were under-predicted, mostly due to the lack of any perturbations in the pressure boundary conditions between cycles. Velocity CCVs for the simulations had the same average magnitude as experiments, but the experimental data showed greater spatial variation in the root-mean-square (RMS). Conversely, circular standard deviation results showed greater repeatability of the flow directionality and swirl vortex positioning than the simulations.« less

Optimal diapause strategies of a grasshopper, Melanoplus sanguinipes

PubMed Central

Fielding, Dennis

2006-01-01

Previous analyses of diapause in insects have most often focused on the timing of the switch from non-diapausing to diapausing offspring in bivoltine populations and have assumed that diapause is irreversible or that the insect cannot survive winter if not in diapause. Many insects exhibit more flexibility in their life cycles, such as the age at which diapause begins, and facultative diapause, that may influence the evolution of different diapause strategies in different environments. The grasshopper Melanoplus sanguinipes F. (Orthoptera: Acrididae), has a very wide geographic range over which diapause characteristics vary greatly. Embryonic diapause in this species may be under maternal control, may be obligate or facultative (i.e., may be averted by cold temperature treatment of pre-diapause embryos), and embryos may enter diapause at different ages. Diapause traits were examined in two populations of M. sanguinipes from very different environments. In the population from a temperate climate (Idaho, USA), diapause was facultative, i.e., pre-diapause embryos averted diapause when held at 5° C for 90 days at all ages tested (7 days and older). The Idaho embryos entered diapause in late stage of development if held at 22° C for 30 days or more. In populations from subarctic Alaska, USA, embryos also entered diapause in a late stage of development, but diapause was obligate and could not be averted by chilling in the pre-diapause stages. Simulated evolution of these traits over a wide range of season-lengths showed that late stage diapause is an essential trait in very short season environments, resulting in early hatching, and a semivoltine life-cycle. Facultative diapause enabled bivoltinism to be a viable strategy in shorter seasons than when diapause was obligate. At transitions from semivoltine to univoltine, and from univoltine to bivoltine life cycles, populations with obligate diapause adopted a strategy of no diapause (via maternal effects) to enable univoltine life cycles. PMID:19537989

A Life Cycle Cost Analysis of Rigid Pavements

DOT National Transportation Integrated Search

1999-09-01

The Texas Department of Transportation (TxDOT)commissioned a research project in 1996, summarized here, to promote life cycle cost analysis of rigid pavements throughout the TxDOT districts by developing a uniform methodology for performing life cycl...

Intersection life cycle cost comparison tool user guide version 1.0.

DOT National Transportation Integrated Search

2016-05-01

The Intersection Life Cycle Cost Comparison Tool User Guide was developed as part of North : Carolina Department of Transportation Research Project No. 201411: Evaluation of Life Cycle : Impacts of Intersection Control Type Selection. : This sprea...

Life Cycle Impact Assessment Research Developments and Needs

EPA Science Inventory

Life Cycle Impact Assessment (LCIA) developments are explained along with key publications which record discussions which comprised ISO 14042 and SETAC document development, UNEP SETAC Life Cycle Initiative research, and research from public and private research institutions. It ...

PCSIM: A Parallel Simulation Environment for Neural Circuits Fully Integrated with Python

PubMed Central

Pecevski, Dejan; Natschläger, Thomas; Schuch, Klaus

2008-01-01

The Parallel Circuit SIMulator (PCSIM) is a software package for simulation of neural circuits. It is primarily designed for distributed simulation of large scale networks of spiking point neurons. Although its computational core is written in C++, PCSIM's primary interface is implemented in the Python programming language, which is a powerful programming environment and allows the user to easily integrate the neural circuit simulator with data analysis and visualization tools to manage the full neural modeling life cycle. The main focus of this paper is to describe PCSIM's full integration into Python and the benefits thereof. In particular we will investigate how the automatically generated bidirectional interface and PCSIM's object-oriented modular framework enable the user to adopt a hybrid modeling approach: using and extending PCSIM's functionality either employing pure Python or C++ and thus combining the advantages of both worlds. Furthermore, we describe several supplementary PCSIM packages written in pure Python and tailored towards setting up and analyzing neural simulations. PMID:19543450

Distributed Observer Network

NASA Technical Reports Server (NTRS)

2008-01-01

NASA s advanced visual simulations are essential for analyses associated with life cycle planning, design, training, testing, operations, and evaluation. Kennedy Space Center, in particular, uses simulations for ground services and space exploration planning in an effort to reduce risk and costs while improving safety and performance. However, it has been difficult to circulate and share the results of simulation tools among the field centers, and distance and travel expenses have made timely collaboration even harder. In response, NASA joined with Valador Inc. to develop the Distributed Observer Network (DON), a collaborative environment that leverages game technology to bring 3-D simulations to conventional desktop and laptop computers. DON enables teams of engineers working on design and operations to view and collaborate on 3-D representations of data generated by authoritative tools. DON takes models and telemetry from these sources and, using commercial game engine technology, displays the simulation results in a 3-D visual environment. Multiple widely dispersed users, working individually or in groups, can view and analyze simulation results on desktop and laptop computers in real time.

Application of Pharmacokinetics and Pharmacodynamics in Product Life Cycle Management. A Case Study with a Carbidopa-Levodopa Extended-Release Formulation.

PubMed

Modi, Nishit B

2017-05-01

Increasing costs in discovering and developing new molecular entities and the continuing debate on limited company pipelines mean that pharmaceutical companies are under significant pressure to maximize the value of approved products. Life cycle management in the context of drug development comprises activities to maximize the effective life of a product. Life cycle approaches can involve new formulations, new routes of delivery, new indications or expansion of the population for whom the product is indicated, or development of combination products. Life cycle management may provide an opportunity to improve upon the current product through enhanced efficacy or reduced side effects and could expand the therapeutic market for the product. Successful life cycle management may include the potential for superior efficacy, improved tolerability, or a better prescriber or patient acceptance. Unlike generic products where bioequivalence to an innovator product may be sufficient for drug approval, life cycle management typically requires a series of studies to characterize the value of the product. This review summarizes key considerations in identifying product candidates that may be suitable for life cycle management and discusses the application of pharmacokinetics and pharmacodynamics in developing new products using a life cycle management approach. Examples and a case study to illustrate how pharmacokinetics and pharmacodynamics contributed to the selection of dosing regimens, demonstration of an improved therapeutic effect, or regulatory approval of an improved product label are presented.

The building loads analysis system thermodynamics (BLAST) program, Version 2. 0: input booklet. Final report

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sowell, E.

1979-06-01

The Building Loads Analysis and System Thermodynamics (BLAST) program is a comprehensive set of subprograms for predicting energy consumption in buildings. There are three major subprograms: (1) the space load predicting subprogram, which computes hourly space loads in a building or zone based on user input and hourly weather data; (2) the air distribution system simulation subprogram, which uses the computed space load and user inputs describing the building air-handling system to calculate hot water or steam, chilled water, and electric energy demands; and (3) the central plant simulation program, which simulates boilers, chillers, onsite power generating equipment and solarmore » energy systems and computes monthly and annual fuel and electrical power consumption and plant life cycle cost.« less

Building Maintenance and Repair Data for Life-Cycle Cost Analyses: Electrical Systems.

DTIC Science & Technology

1991-05-01

Repair Data for Life-Cycle Cost Analyses: Electrical Systems by Edgar S. Neely Robert D. Neathammer James R. Stirn Robert P. Winkler This research...systems have been developed to assist planners in preparing DD Form 1391 documentation, designers in life-cycle cost component selection, and maintainers...Maintenance and Repair Data for Life-Cycle Cost Analyses: RDTE dated 1980 Electrical Systems REIMB 1984 - 1989 6. AUTH4OR(S) Edgar S. Neely, Robert D

Why Army Program Managers Struggle As Life Cycle Managers: A Study of the PM’s Roles, Responsibilities, and Barriers In the Execution of Operations and Support

DTIC Science & Technology

2016-09-01

Support Strategies (PBPSS), throughout the system life cycle .  Maximizing competition, to include small business participation.  Developing...NAVAL POSTGRADUATE SCHOOL MONTEREY, CALIFORNIA JOINT APPLIED PROJECT WHY ARMY PROGRAM MANAGERS STRUGGLE AS LIFE CYCLE MANAGERS...SUBTITLE WHY ARMY PROGRAM MANAGERS STRUGGLE AS LIFE CYCLE MANAGERS: A STUDY OF THE PM’S ROLES, RESPONSIBILITIES, AND BARRIERS IN THE EXECUTION OF

Identification of fuel cycle simulator functionalities for analysis of transition to a new fuel cycle

DOE PAGES

Brown, Nicholas R.; Carlsen, Brett W.; Dixon, Brent W.; ...

2016-06-09

Dynamic fuel cycle simulation tools are intended to model holistic transient nuclear fuel cycle scenarios. As with all simulation tools, fuel cycle simulators require verification through unit tests, benchmark cases, and integral tests. Model validation is a vital aspect as well. Although compara-tive studies have been performed, there is no comprehensive unit test and benchmark library for fuel cycle simulator tools. The objective of this paper is to identify the must test functionalities of a fuel cycle simulator tool within the context of specific problems of interest to the Fuel Cycle Options Campaign within the U.S. Department of Energy smore » Office of Nuclear Energy. The approach in this paper identifies the features needed to cover the range of promising fuel cycle options identified in the DOE-NE Fuel Cycle Evaluation and Screening (E&S) and categorizes these features to facilitate prioritization. Features were categorized as essential functions, integrating features, and exemplary capabilities. One objective of this paper is to propose a library of unit tests applicable to each of the essential functions. Another underlying motivation for this paper is to encourage an international dialog on the functionalities and standard test methods for fuel cycle simulator tools.« less

Evolutionary lability of a complex life cycle in the aphid genus Brachycaudus.

PubMed

Emmanuelle, Jousselin; Gwenaelle, Genson; Armelle, Coeur d'acier

2010-09-28

Most aphid species complete their life cycle on the same set of host-plant species, but some (heteroecious species) alternate between different hosts, migrating from primary (woody) to secondary (herbaceous) host plants. The evolutionary processes behind the evolution of this complex life cycle have often been debated. One widely accepted scenario is that heteroecy evolved from monoecy on woody host plants. Several shifts towards monoecy on herbaceous plants have subsequently occurred and resulted in the radiation of aphids. Host alternation would have persisted in some cases due to developmental constraints preventing aphids from shifting their entire life cycle to herbaceous hosts (which are thought to be more favourable). According to this scenario, if aphids lose their primary host during evolution they should not regain it. The genus Brachycaudus includes species with all the types of life cycle (monoecy on woody plants, heteroecy, monoecy on herbs). We used this genus to test hypotheses concerning the evolution of life cycles in aphids. Phylogenetic investigation and character reconstruction suggest that life cycle is evolutionary labile in the genus. Though ancestral character states can be ambiguous depending on optimization methods, all analyses suggest that transitions from monoecy on herbs towards heteroecy have occurred several times. Transitions from heteroecy towards monoecy, are also likely. There have been many shifts in feeding behaviour but we found no significant correlation between life cycle changes and changes in diet. The transitions from monoecy on herbs towards heteroecy observed in this study go against a widely accepted evolutionary scenario: aphids in the genus Brachycaudus seem to be able to recapture their supposedly ancestral woody host. This suggests that the determinants of host alternation are probably not as complicated as previously thought. Definitive proofs of the lability of life cycle in Brachycaudus will necessitate investigation of these determinants. Life cycle changes, whether corresponding to the loss or acquisition of a primary host, necessarily promote speciation, by inducing shifts of the reproductive phase on different plants. We suggest that the evolutionary lability of life cycle may have driven speciation events in the Brachycaudus genus.

Switchgrass Biofuel Research: Carbon Sequestration and Life Cycle Analysis (a.k.a. Second Generation Biofuels: Carbon Sequestration and Life Cycle Analysis)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Liska, Adam J.; Suyker, Andrew E.; Arkebauer, Timothy J.

2013-12-20

Soil emissions have been inadequately characterized in life cycle assessment of biofuels (see section 3.2.3). This project measures the net differences in field-level greenhouse gas emissions (CO 2, N 2O, and CH 4) due to corn residue removal for cellulosic ethanol production. Gas measurements are then incorporated into life cycle assessment of the final biofuel product to determine whether it is in compliance with federal greenhouse gas emissions standards for biofuels (Renewable Fuel Standard 2, RFS2). The field measurements have been conducted over three years on two, quarter-section, production-scale, irrigated corn fields (both roughly 50 hectares, as this size ofmore » field is necessary for reproducible eddy covariance flux measurements of CO 2; chamber measurements are used to determine N 2O and CH 4 emissions). Due to a large hail storm in 2010, estimates of the emission from residue could not be separated from the total CO 2 flux in 2011. This led us to develop soil organic carbon (SOC) modeling techniques to estimate changes in CO 2 emissions from residue removal. Modeling has predicted emissions of CO 2 from oxidation of SOC that are consistent (<12%) with 9 years of CO 2 flux measurements at the two production field sites, and modeling is also consistent with other field measurements (Liska et al., submitted). The model was then used to estimate the average change in SOC and CO 2 emissions from nine years of simulated residue removal (6 Mg biomass per hectare per year) at the sites; a loss of 0.43 Mg C ha -1 yr -1 resulted. The model was then used to estimate SOC changes over 10 years across Nebraska using supercomputing, based on 61 million, 30 x 30 meter, grid cells to account for regional variability in initial SOC, crop yield, and temperature; an average loss of 0.47 Mg C ha -1 yr -1 resulted. When these CO 2 emissions are included in simple life cycle assessment calculations, emissions from cellulosic ethanol from crop residue are above mandated levels of 60% reduction compared to gasoline (Liska, in press). These approaches are both technically effective and economically feasible. This work has been extensively peer reviewed.« less

Uncertainty in life cycle greenhouse gas emissions from United States natural gas end-uses and its effects on policy.

PubMed

Venkatesh, Aranya; Jaramillo, Paulina; Griffin, W Michael; Matthews, H Scott

2011-10-01

Increasing concerns about greenhouse gas (GHG) emissions in the United States have spurred interest in alternate low carbon fuel sources, such as natural gas. Life cycle assessment (LCA) methods can be used to estimate potential emissions reductions through the use of such fuels. Some recent policies have used the results of LCAs to encourage the use of low carbon fuels to meet future energy demands in the U.S., without, however, acknowledging and addressing the uncertainty and variability prevalent in LCA. Natural gas is a particularly interesting fuel since it can be used to meet various energy demands, for example, as a transportation fuel or in power generation. Estimating the magnitudes and likelihoods of achieving emissions reductions from competing end-uses of natural gas using LCA offers one way to examine optimal strategies of natural gas resource allocation, given that its availability is likely to be limited in the future. In this study, the uncertainty in life cycle GHG emissions of natural gas (domestic and imported) consumed in the U.S. was estimated using probabilistic modeling methods. Monte Carlo simulations are performed to obtain sample distributions representing life cycle GHG emissions from the use of 1 MJ of domestic natural gas and imported LNG. Life cycle GHG emissions per energy unit of average natural gas consumed in the U.S were found to range between -8 and 9% of the mean value of 66 g CO(2)e/MJ. The probabilities of achieving emissions reductions by using natural gas for transportation and power generation, as a substitute for incumbent fuels such as gasoline, diesel, and coal were estimated. The use of natural gas for power generation instead of coal was found to have the highest and most likely emissions reductions (almost a 100% probability of achieving reductions of 60 g CO(2)e/MJ of natural gas used), while there is a 10-35% probability of the emissions from natural gas being higher than the incumbent if it were used as a transportation fuel. This likelihood of an increase in GHG emissions is indicative of the potential failure of a climate policy targeting reductions in GHG emissions.

Life-cycle implications of hydrogen fuel cell electric vehicle technology for medium- and heavy-duty trucks

NASA Astrophysics Data System (ADS)

Lee, Dong-Yeon; Elgowainy, Amgad; Kotz, Andrew; Vijayagopal, Ram; Marcinkoski, Jason

2018-07-01

This study provides a comprehensive and up-to-date life-cycle comparison of hydrogen fuel cell electric trucks (FCETs) and their conventional diesel counterparts in terms of energy use and air emissions, based on the ensemble of well-established methods, high-fidelity vehicle dynamic simulations, and real-world vehicle test data. For the centralized steam methane reforming (SMR) pathway, hydrogen FCETs reduce life-cycle or well-to-wheel (WTW) petroleum energy use by more than 98% compared to their diesel counterparts. The reduction in WTW air emissions for gaseous hydrogen (G.H2) FCETs ranges from 20 to 45% for greenhouse gases, 37-65% for VOC, 49-77% for CO, 62-83% for NOx, 19-43% for PM10, and 27-44% for PM2.5, depending on vehicle weight classes and truck types. With the current U.S. average electricity generation mix, FCETs tend to create more WTW SOx emissions than their diesel counterparts, mainly because of the upstream emissions related to electricity use for hydrogen compression/liquefaction. Compared to G.H2, liquid hydrogen (L.H2) FCETs generally provide smaller WTW emissions reductions. For both G.H2 and L.H2 pathways for FCETs, because of electricity consumption for compression and liquefaction, spatio-temporal variations of electricity generation can affect the WTW results. FCETs retain the WTW emission reduction benefits, even when considering aggressive diesel engine efficiency improvement.

Sarcocyst Development in Raccoons (Procyon lotor) Inoculated with Different Strains of Sarcocystis neurona Culture-Derived Merozoites.

PubMed

Dryburgh, E L; Marsh, A E; Dubey, J P; Howe, D K; Reed, S M; Bolten, K E; Pei, W; Saville, W J A

2015-08-01

Sarcocystis neurona is considered the major etiologic agent of equine protozoal myeloencephalitis (EPM), a neurological disease in horses. Raccoon ( Procyon lotor ) is considered the most important intermediate host in the life cycle of S. neurona in the United States; S. neurona sarcocysts do mature in raccoon muscles, and raccoons also develop clinical signs simulating EPM. The focus of this study was to determine if sarcocysts would develop in raccoons experimentally inoculated with different host-derived strains of in vitro-cultivated S. neurona merozoites. Four raccoons were inoculated with strains derived from a raccoon, a sea otter, a cat, and a horse. Raccoon tissues were fed to laboratory-raised opossums ( Didelphis virginiana ), the definitive host of S. neurona . Intestinal scraping revealed sporocysts in opossums who received muscle tissue from raccoons inoculated with the raccoon-derived or the sea otter-derived isolates. These results demonstrate that sarcocysts can mature in raccoons inoculated with in vitro-derived S. neurona merozoites. In contrast, the horse and cat-derived isolates did not produce microscopically or biologically detected sarcocysts. Immunoblot analysis revealed both antigenic and antibody differences when testing the inoculated raccoons. Immunohistochemical staining indicated differences in staining between the merozoite and sarcocyst stages. The successful infections achieved in this study indicates that the life cycle can be manipulated in the laboratory without affecting subsequent stage development, thereby allowing further purification of strains and artificial maintenance of the life cycle.

Life-Cycle Implications of Hydrogen Fuel Cell Electric Vehicle Technology for Medium- and Heavy-Duty Trucks

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kotz, Andrew J; Le, Dong-Yeon; Elgowainy, Amgad

This study provides a comprehensive and up-to-date life-cycle comparison of hydrogen fuel cell electric trucks (FCETs) and their conventional diesel counterparts in terms of energy use and air emissions, based on the ensemble of well-established methods, high-fidelity vehicle dynamic simulations, and real-world vehicle test data. For the centralized steam methane reforming (SMR) pathway, hydrogen FCETs reduce life-cycle or well-to-wheel (WTW) petroleum energy use by more than 98% compared to their diesel counterparts. The reduction in WTW air emissions for gaseous hydrogen (G.H2) FCETs ranges from 20 to 45% for greenhouse gases, 37-65% for VOC, 49-77% for CO, 62-83% for NOx,more » 19-43% for PM10, and 27-44% for PM2.5, depending on vehicle weight classes and truck types. With the current U.S. average electricity generation mix, FCETs tend to create more WTW SOx emissions than their diesel counterparts, mainly because of the upstream emissions related to electricity use for hydrogen compression/liquefaction. Compared to G.H2, liquid hydrogen (L.H2) FCETs generally provide smaller WTW emissions reductions. For both G.H2 and L.H2 pathways for FCETs, because of electricity consumption for compression and liquefaction, spatio-temporal variations of electricity generation can affect the WTW results. FCETs retain the WTW emission reduction benefits, even when considering aggressive diesel engine efficiency improvement.« less

Corrosion-fatigue of laser-repaired commercially pure titanium and Ti-6Al-4V alloy under different test environments.

PubMed

Zavanelli, R A; Guilherme, A S; Pessanha-Henriques, G E; de Arruda Nóbilo, M Antônio; Mesquita, M F

2004-10-01

This study evaluated the corrosion-fatigue life of laser-repaired specimens fabricated from commercially pure titanium (CP Ti) and Ti-6Al-4V alloy, tested under different storage conditions. For each metal, 30 dumbbell rods with a central 2.3 mm diameter were prepared by lost-wax casting with the Rematitan System. Simulating the failure after service, corrosion-fatigue life in different media at room temperature (air, synthetic saliva and fluoride synthetic saliva) was determined at a testing frequency of 10 Hz for intact specimens and after laser repairing, using a square waveform with equal maximum tensile and compressive stress that was 30% lower than the 0.2% offset yield strength. For laser welding, the fractured specimens were rejoined using a jig to align the sections invested in type-IV dental stone. The adjacent areas of the gap was air-abraded with 100 microm aluminum oxide, laser welded and retested under the same conditions as the initial intact specimens. The number of cycles at failure was recorded, and the fracture surface was examined with a scanning electron microscope (SEM). The number of cycles for failure of the welded and intact specimens was compared by anova and the Tukey test at a 5% probability level. Within the limitations of this study, the number of cycles required for fracture decreased in wet environments and the laser repairing process adversely affected the life of both metals under the corrosion-fatigue conditions.

Caed Interactions During A Product Life Cycle Oriented Towards the Decision-Making in the Design of Polymeric Elements

NASA Astrophysics Data System (ADS)

Suffo, M.

2017-08-01

In this work, we present the real case of an industrial product was placed prematurely on the market without having checked the different stages of its life cycle. This type of products must be validated by numerical methods and by mechanical tests to verify their rheological behavior. In particular, the product consists of two small pieces in contact, one made of HDPE and the other one corresponding to a stainless steel. The polymeric piece supports the metal pressure under a constant static load over time. As a result of normal operation, the polymer experienced a “crazing” breakdown, which caused the failure to occur. In the study, design methods and computer assisted analysis software (CAED) have been used. These methods were complemented by scanning electron microscopy that confirmed the initial failure hypothesis. Using the finite element method (FEM), a series of load scenarios were carried out, where the different load hypothesis the product must go through prior to its placing on the market were simulated. It is shown that the failure was initiated by stress concentration on one of the edges of the polymeric piece. The proposed solution of the problem based on the analysis focuses on a simple redesign of the piece, which should have been round, or to the reduction of the thickness of the metal piece. As a result of the alteration of its natural life cycle, the company assumed both monetary costs and the definitive loss of customer confidence.

The dynamical structure of intense Mediterranean cyclones

NASA Astrophysics Data System (ADS)

Flaounas, Emmanouil; Raveh-Rubin, Shira; Wernli, Heini; Drobinski, Philippe; Bastin, Sophie

2015-05-01

This paper presents and analyzes the three-dimensional dynamical structure of intense Mediterranean cyclones. The analysis is based on a composite approach of the 200 most intense cyclones during the period 1989-2008 that have been identified and tracked using the output of a coupled ocean-atmosphere regional simulation with 20 km horizontal grid spacing and 3-hourly output. It is shown that the most intense Mediterranean cyclones have a common baroclinic life cycle with a potential vorticity (PV) streamer associated with an upper-level cyclonic Rossby wave breaking, which precedes cyclogenesis in the region and triggers baroclinic instability. It is argued that this common baroclinic life cycle is due to the strongly horizontally sheared environment in the Mediterranean basin, on the poleward flank of the quasi-persistent subtropical jet. The composite life cycle of the cyclones is further analyzed considering the evolution of key atmospheric elements as potential temperature and PV, as well as the cyclones' thermodynamic profiles and rainfall. It is shown that most intense Mediterranean cyclones are associated with warm conveyor belts and dry air intrusions, similar to those of other strong extratropical cyclones, but of rather small scale. Before cyclones reach their mature stage, the streamer's role is crucial to advect moist and warm air towards the cyclones center. These dynamical characteristics, typical for very intense extratropical cyclones in the main storm track regions, are also valid for these Mediterranean cases that have features that are visually similar to tropical cyclones.

5 CFR 930.301 - Information systems security awareness training program.

Code of Federal Regulations, 2012 CFR

2012-01-01

... training in system/application life cycle management, risk management, and contingency planning. (4) Chief... security management, system/application life cycle management, risk management, and contingency planning... management; and management and implementation level training in system/application life cycle management...

Life Cycle Assessment for Biofuels

EPA Science Inventory

A presentation based on life cycle assessment (LCA) for biofuels is given. The presentation focuses on energy and biofuels, interesting environmental aspects of biofuels, and how to do a life cycle assessment with some examples related to biofuel systems. The stages of a (biofuel...

Data Base Development of Automobile and Light Truck Maintenance : Volume II. Appendix E.

DOT National Transportation Integrated Search

1978-08-01

The document contains the scheduled maintenance data sheets and total cost summaries--both scheduled and unscheduled maintenance (Life cycle cost for Dealers, life cycle cost for Service Stations, life cycle cost for Independent Repair, and scheduled...

Data Base Development of Automobile and Light Truck Maintenance : Volume III. Appendix F.

DOT National Transportation Integrated Search

1978-08-01

The document contains the scheduled maintenance data sheets and total cost summaries--both scheduled and unscheduled maintenance (Life cycle cost for Dealers, life cycle cost for Service Stations, life cycle cost for Independent Repair, and scheduled...

LIFE CYCLE ASSESSMENT: PRINCIPLES AND PRACTICE

EPA Science Inventory

The following document provides an introductory overview of Life Cycle Assessment (LCA) and describes the general uses and major components of LCA. This document is an update and merger of two previous EPA documents on LCA ("Life Cycle Assessment: Inventory Guidelines and Princip...

Refrigerant Performance Evaluation Including Effects of Transport Properties and Optimized Heat Exchangers.

PubMed

Brignoli, Riccardo; Brown, J Steven; Skye, H; Domanski, Piotr A

2017-08-01

Preliminary refrigerant screenings typically rely on using cycle simulation models involving thermodynamic properties alone. This approach has two shortcomings. First, it neglects transport properties, whose influence on system performance is particularly strong through their impact on the performance of the heat exchangers. Second, the refrigerant temperatures in the evaporator and condenser are specified as input, while real-life equipment operates at imposed heat sink and heat source temperatures; the temperatures in the evaporator and condensers are established based on overall heat transfer resistances of these heat exchangers and the balance of the system. The paper discusses a simulation methodology and model that addresses the above shortcomings. This model simulates the thermodynamic cycle operating at specified heat sink and heat source temperature profiles, and includes the ability to account for the effects of thermophysical properties and refrigerant mass flux on refrigerant heat transfer and pressure drop in the air-to-refrigerant evaporator and condenser. Additionally, the model can optimize the refrigerant mass flux in the heat exchangers to maximize the Coefficient of Performance. The new model is validated with experimental data and its predictions are contrasted to those of a model based on thermodynamic properties alone.

Defense AR Journal, Volume 15, Number 1, April 2008

DTIC Science & Technology

2008-04-01

Beavers William Ruta DAUAA Research Paper Competition: 3rd Place Employing Organizational Modeling & Simulation of the KC-135 Depot’s Flight Controls Maj...AttAck munition SYStemS (jAmS) Project office imProvinG SuPPort to the wArfiGhter Barry Beavers and William Ruta The Joint Attack Munition Systems...William Ruta . This paper examines how the JAMS Project Office improved support to the warfighter with its implementation of the Life Cycle

CALiPER Exploratory Study. Recessed Troffer Lighting

DOE Office of Scientific and Technical Information (OSTI.GOV)

Miller, N. J.; Royer, M. P.; Poplawski, M. E.

This CALiPER study examines the problems and benefits likely to be encountered with LED products intended to replace linear fluorescent lamps. LED dedicated troffers, replacement tubes, and non-tube retrofit kits were evaluated against fluorescent benchmark troffers in a simulated office space for photometric distribution, uniformity of light on the task surface, suitability of light output, flicker, dimming performance, color quality, power quality, safety and certification issues, ease of installation, energy efficiency, and life-cycle cost.

Maintenance Training Simulators Prime Item Development Specification. Model Specification and Handbook.

DTIC Science & Technology

1985-04-01

and equipment whose operation can be verified with a visual or aural check. The sequence of outputs shall be cyclic, with provisions to stop the...private memory. The decision to provide spare, expansion capability, or a combination of both shall be based on life cycle cost (to the best extent...Computational System should be determined in conjunction with a computer expert (if possible). In any event, it is best to postpone completing - this

Modeling and Analysis of Global and Regional Climate Change in Relation to Atmospheric Hydrologic Processes

NASA Technical Reports Server (NTRS)

Johnson, Donald R.

2001-01-01

This research was directed to the development and application of global isentropic modeling and analysis capabilities to describe hydrologic processes and energy exchange in the climate system, and discern regional climate change. An additional objective was to investigate the accuracy and theoretical limits of global climate predictability which are imposed by the inherent limitations of simulating trace constituent transport and the hydrologic processes of condensation, precipitation and cloud life cycles.

Hybrid power systems for autonomous MEMS

NASA Astrophysics Data System (ADS)

Bennett, Daniel M.; Selfridge, Richard H.; Humble, Paul; Harb, John N.

2001-08-01

This paper describes the design of a hybrid power system for use with autonomous MEMS and other microdevices. This hybrid power system includes energy conversion and storage along with an electronic system for managing the collection and distribution of power. It offers flexibility and longevity in a compact package. The hybrid power system couples a silicon solar cell with a microbattery specially designed for MEMS applications. We have designed a control/interface charging circuit to be compatible with a MEMS duty cycle. The design permits short pulses of 'high' power while taking care to avoid excessive charging or discharging of the battery. Charging is carefully controlled to provide a balance between acceptably small charging times and a charging profile that extends battery life. Our report describes the charging of our Ni/Zn microbatteries using solar cells. To date we have demonstrated thousands of charge/discharge cycles of a simulated MEMS duty cycle.

An application of queuing theory to waterfowl migration

USGS Publications Warehouse

Sojda, Richard S.; Cornely, John E.; Fredrickson, Leigh H.; Rizzoli, A.E.; Jakeman, A.J.

2002-01-01

There has always been great interest in the migration of waterfowl and other birds. We have applied queuing theory to modelling waterfowl migration, beginning with a prototype system for the Rocky Mountain Population of trumpeter swans (Cygnus buccinator) in Western North America. The queuing model can be classified as a D/BB/28 system, and we describe the input sources, service mechanism, and network configuration of queues and servers. The intrinsic nature of queuing theory is to represent the spatial and temporal characteristics of entities and how they move, are placed in queues, and are serviced. The service mechanism in our system is an algorithm representing how swans move through the flyway based on seasonal life cycle events. The system uses an observed number of swans at each of 27 areas for a breeding season as input and simulates their distribution through four seasonal steps. The result is a simulated distribution of birds for the subsequent year's breeding season. The model was built as a multiagent system with one agent handling movement algorithms, with one facilitating user interface, and with one to seven agents representing specific geographic areas for which swan management interventions can be implemented. The many parallels in queuing model servers and service mechanisms with waterfowl management areas and annual life cycle events made the transfer of the theory to practical application straightforward.

On the sensitivities of idealized moist baroclinic waves to environmental temperature and moist convection

NASA Astrophysics Data System (ADS)

Kirshbaum, Daniel; Merlis, Timothy; Gyakum, John; McTaggart-Cowan, Ron

2017-04-01

The impact of cloud diabatic heating on baroclinic life cycles has been studied for decades, with the nearly universal finding that this heating enhances the system growth rate. However, few if any studies have systematically addressed the sensitivity of baroclinic waves to environmental temperature. For a given relative humidity, warmer atmospheres contain more moisture than colder atmospheres. They also are more prone to the development of deep moist convection, which is itself a major source of diabatic heating. Thus, it is reasonable to expect faster baroclinic wave growth in warmer systems. To address this question, this study performs idealized simulations of moist baroclinic waves in a periodic channel, using initial environments with identical relative humidities, dry stabilities, and dry available potential energies but varying environmental temperatures and moist instabilities. While the dry versions of these simulations exhibit virtually identical wave growth, the moist versions exhibit major differences in life cycle. Counter-intuitively, despite slightly faster initial wave growth, the warmer and moister waves ultimately develop into weaker baroclinic systems with an earlier onset of the decay phase. An energetics analysis reveals that the reduced wave amplitude in the warmer cases stems from a reduced transfer of available potential energy into eddy potential energy. This reduced energy transfer is associated with an unfavorable phasing of mid-to-upper-level thermal and vorticity anomalies, which limits the meridional heat flux.

Developing a dynamic life cycle greenhouse gas emission inventory for wood construction for two different end-of-life scenarios

Treesearch

Richard D. Bergman; James Salazar; Scott Bowe

2012-01-01

Static life cycle assessment does not fully describe the carbon footprint of construction wood because of carbon changes in the forest and product pools over time. This study developed a dynamic greenhouse gas (GHG) inventory approach using US Forest Service and life-cycle data to estimate GHG emissions on construction wood for two different end-of-life scenarios....

A Methodology for Integrated, Multiregional Life Cycle Assessment Scenarios under Large-Scale Technological Change.

PubMed

Gibon, Thomas; Wood, Richard; Arvesen, Anders; Bergesen, Joseph D; Suh, Sangwon; Hertwich, Edgar G

2015-09-15

Climate change mitigation demands large-scale technological change on a global level and, if successfully implemented, will significantly affect how products and services are produced and consumed. In order to anticipate the life cycle environmental impacts of products under climate mitigation scenarios, we present the modeling framework of an integrated hybrid life cycle assessment model covering nine world regions. Life cycle assessment databases and multiregional input-output tables are adapted using forecasted changes in technology and resources up to 2050 under a 2 °C scenario. We call the result of this modeling "technology hybridized environmental-economic model with integrated scenarios" (THEMIS). As a case study, we apply THEMIS in an integrated environmental assessment of concentrating solar power. Life-cycle greenhouse gas emissions for this plant range from 33 to 95 g CO2 eq./kWh across different world regions in 2010, falling to 30-87 g CO2 eq./kWh in 2050. Using regional life cycle data yields insightful results. More generally, these results also highlight the need for systematic life cycle frameworks that capture the actual consequences and feedback effects of large-scale policies in the long term.

THE COMPONENTS OF KIN COMPETITION

PubMed Central

Van Dyken, J. David

2011-01-01

It is well known that competition among kin alters the rate and often the direction of evolution in subdivided populations. Yet much remains unclear about the ecological and demographic causes of kin competition, or what role life cycle plays in promoting or ameliorating its effects. Using the multilevel Price equation, I derive a general equation for evolution in structured populations under an arbitrary intensity of kin competition. This equation partitions the effects of selection and demography, and recovers numerous previous models as special cases. I quantify the degree of kin competition, α, which explicitly depends on life cycle. I show how life cycle and demographic assumptions can be incorporated into kin selection models via α, revealing life cycles that are more or less permissive of altruism. As an example, I give closed-form results for Hamilton’s rule in a three-stage life cycle. Although results are sensitive to life cycle in general, I identify three demographic conditions that give life cycle invariant results. Under the infinite island model, α is a function of the scale of density regulation and dispersal rate, effectively disentangling these two phenomena. Population viscosity per se does not impede kin selection. PMID:20482610

Predicting the 3D fatigue crack growth rate of small cracks using multimodal data via Bayesian networks: In-situ experiments and crystal plasticity simulations

DOE Office of Scientific and Technical Information (OSTI.GOV)

Rovinelli, Andrea; Sangid, Michael D.; Proudhon, Henry

Small crack propagation accounts for most of the fatigue life of engineering structures subject to high cycle fatigue loading conditions. Determining the fatigue crack growth rate of small cracks propagating into polycrystalline engineering alloys is critical to improving fatigue life predictions, thus lowering cost and increasing safety. In this work, cycle-by-cycle data of a small crack propagating in a beta metastable titanium alloy is available via phase and diffraction contrast tomography. Crystal plasticity simulations are used to supplement experimental data regarding the micromechanical fields ahead of the crack tip. Experimental and numerical results are combined into a multimodal dataset andmore » sampled utilizing a non-local data mining procedure. Furthermore, to capture the propensity of body-centered cubic metals to deform according to the pencil-glide model, a non-local driving force is postulated. The proposed driving force serves as the basis to construct a data-driven probabilistic crack propagation framework using Bayesian networks as building blocks. The spatial correlation between the postulated driving force and experimental observations is obtained by analyzing the results of the proposed framework. Results show that the above correlation increases proportionally to the distance from the crack front until the edge of the plastic zone. Moreover, the predictions of the propagation framework show good agreement with experimental observations. Finally, we studied the interaction of a small crack with grain boundaries (GBs) utilizing various slip transmission criteria, revealing the tendency of a crack to cross a GB by propagating along the slip directions minimizing the residual Burgers vector within the GB.« less

Predicting the 3D fatigue crack growth rate of small cracks using multimodal data via Bayesian networks: In-situ experiments and crystal plasticity simulations

NASA Astrophysics Data System (ADS)

Rovinelli, Andrea; Sangid, Michael D.; Proudhon, Henry; Guilhem, Yoann; Lebensohn, Ricardo A.; Ludwig, Wolfgang

2018-06-01

Small crack propagation accounts for most of the fatigue life of engineering structures subject to high cycle fatigue loading conditions. Determining the fatigue crack growth rate of small cracks propagating into polycrystalline engineering alloys is critical to improving fatigue life predictions, thus lowering cost and increasing safety. In this work, cycle-by-cycle data of a small crack propagating in a beta metastable titanium alloy is available via phase and diffraction contrast tomography. Crystal plasticity simulations are used to supplement experimental data regarding the micromechanical fields ahead of the crack tip. Experimental and numerical results are combined into a multimodal dataset and sampled utilizing a non-local data mining procedure. Furthermore, to capture the propensity of body-centered cubic metals to deform according to the pencil-glide model, a non-local driving force is postulated. The proposed driving force serves as the basis to construct a data-driven probabilistic crack propagation framework using Bayesian networks as building blocks. The spatial correlation between the postulated driving force and experimental observations is obtained by analyzing the results of the proposed framework. Results show that the above correlation increases proportionally to the distance from the crack front until the edge of the plastic zone. Moreover, the predictions of the propagation framework show good agreement with experimental observations. Finally, we studied the interaction of a small crack with grain boundaries (GBs) utilizing various slip transmission criteria, revealing the tendency of a crack to cross a GB by propagating along the slip directions minimizing the residual Burgers vector within the GB.

Universal Sequence Replication, Reversible Polymerization and Early Functional Biopolymers: A Model for the Initiation of Prebiotic Sequence Evolution

PubMed Central

Walker, Sara Imari; Grover, Martha A.; Hud, Nicholas V.

2012-01-01

Many models for the origin of life have focused on understanding how evolution can drive the refinement of a preexisting enzyme, such as the evolution of efficient replicase activity. Here we present a model for what was, arguably, an even earlier stage of chemical evolution, when polymer sequence diversity was generated and sustained before, and during, the onset of functional selection. The model includes regular environmental cycles (e.g. hydration-dehydration cycles) that drive polymers between times of replication and functional activity, which coincide with times of different monomer and polymer diffusivity. Template-directed replication of informational polymers, which takes place during the dehydration stage of each cycle, is considered to be sequence-independent. New sequences are generated by spontaneous polymer formation, and all sequences compete for a finite monomer resource that is recycled via reversible polymerization. Kinetic Monte Carlo simulations demonstrate that this proposed prebiotic scenario provides a robust mechanism for the exploration of sequence space. Introduction of a polymer sequence with monomer synthetase activity illustrates that functional sequences can become established in a preexisting pool of otherwise non-functional sequences. Functional selection does not dominate system dynamics and sequence diversity remains high, permitting the emergence and spread of more than one functional sequence. It is also observed that polymers spontaneously form clusters in simulations where polymers diffuse more slowly than monomers, a feature that is reminiscent of a previous proposal that the earliest stages of life could have been defined by the collective evolution of a system-wide cooperation of polymer aggregates. Overall, the results presented demonstrate the merits of considering plausible prebiotic polymer chemistries and environments that would have allowed for the rapid turnover of monomer resources and for regularly varying monomer/polymer diffusivities. PMID:22493682

Predicting the 3D fatigue crack growth rate of small cracks using multimodal data via Bayesian networks: In-situ experiments and crystal plasticity simulations

DOE PAGES

Rovinelli, Andrea; Sangid, Michael D.; Proudhon, Henry; ...

2018-03-11

Small crack propagation accounts for most of the fatigue life of engineering structures subject to high cycle fatigue loading conditions. Determining the fatigue crack growth rate of small cracks propagating into polycrystalline engineering alloys is critical to improving fatigue life predictions, thus lowering cost and increasing safety. In this work, cycle-by-cycle data of a small crack propagating in a beta metastable titanium alloy is available via phase and diffraction contrast tomography. Crystal plasticity simulations are used to supplement experimental data regarding the micromechanical fields ahead of the crack tip. Experimental and numerical results are combined into a multimodal dataset andmore » sampled utilizing a non-local data mining procedure. Furthermore, to capture the propensity of body-centered cubic metals to deform according to the pencil-glide model, a non-local driving force is postulated. The proposed driving force serves as the basis to construct a data-driven probabilistic crack propagation framework using Bayesian networks as building blocks. The spatial correlation between the postulated driving force and experimental observations is obtained by analyzing the results of the proposed framework. Results show that the above correlation increases proportionally to the distance from the crack front until the edge of the plastic zone. Moreover, the predictions of the propagation framework show good agreement with experimental observations. Finally, we studied the interaction of a small crack with grain boundaries (GBs) utilizing various slip transmission criteria, revealing the tendency of a crack to cross a GB by propagating along the slip directions minimizing the residual Burgers vector within the GB.« less

[Specific manifestations of polyvariant life cycles in ground beetles (Coleoptera, Carabidae) along latitudinal gradient].

PubMed

Matalin, A V

2014-01-01

The life cycles of Carabidae are highly diverse, and 25 variants of these cycles are realized In the European part of Russia, from semideserts to continental tundras. The diversity of the life cycle spectrum sharply decreases (by more than half) upon transition from nemoral to boreal forest communities, and its phenological unification takes place at high latitudes. The greatest proportion of species with polyvariant development (25%) is characteristic of temporal latitudes, which may be explained by relatively long growing season and considerable cenotic diversity. In both southern (semidesert and steppe) and northern regions (middle and northern boreal forests), this proportion does not exceed 5%. At low latitudes, the polyvariant pattern of development is often manifested in the form of facultative bivoltine life cycles or as facultative biennial life cycles in species with the initial "spring" breeding type.

Long life monopropellant hydrazine thruster evaluation for Space Station Freedom application

NASA Technical Reports Server (NTRS)

Popp, Christopher G.; Henderson, John B.

1991-01-01

In support of propulsion system thruster development activity for Space Station Freedom (SSF), NASA Johnson Space Center (JSC) is conducting a hydrazine thruster technology demonstration program. The goal of this program is to identify impulse life capability of state-of-the-art long life hydrazine thrusters nominally rated for 50 pounds thrust at 300 psia supply pressure. The SSF propulsion system requirement for impulse life of this thruster class is 1.5 million pound-seconds, corresponding to a throughput of approximately 6400 pounds of propellant, with a high performance (234 pound-seconds per propellant pound). Long life thrusters were procured from Hamilton Standard, The Marquardt Company, and Rocket Research Company. Testing has initiated on the thruster designs to identify life while simulating expected thruster firing duty cycles and durations for SSF using monopropellant grade hydrazine. This paper presents a review of the SSF propulsion system and requirements as applicable to hydrazine thrusters, the three long life thruster designs procured by JSC and the resultant acceptance test data for each thruster, and the JSC test plan and facility.

USING LIFE CYCLE ASSESSMENT TOOLS FOR INTEGRATED PRODUCT POLICY

EPA Science Inventory

The European Union's new Integrated Product Policy directs governments and companies to consider the entire product life cycle, from cradle to grave, in their environmental decision-making process. A life-cycle based approach is intended to lead toward true environmental improvem...

41 CFR 109-1.5304 - Deviations.

Code of Federal Regulations, 2010 CFR

2010-07-01

... High Risk Personal Property § 109-1.5304 Deviations. (a) Life cycle control determinations. When the HFO approves a contractor program containing controls, other than life cycle control consistent with... Secretary for Procurement and Assistance Management. A HFO's decision not to provide life-cycle control...

41 CFR 109-1.5304 - Deviations.

Code of Federal Regulations, 2013 CFR

2013-07-01

... High Risk Personal Property § 109-1.5304 Deviations. (a) Life cycle control determinations. When the HFO approves a contractor program containing controls, other than life cycle control consistent with... Secretary for Procurement and Assistance Management. A HFO's decision not to provide life-cycle control...

41 CFR 109-1.5304 - Deviations.

Code of Federal Regulations, 2014 CFR

2014-01-01

... High Risk Personal Property § 109-1.5304 Deviations. (a) Life cycle control determinations. When the HFO approves a contractor program containing controls, other than life cycle control consistent with... Secretary for Procurement and Assistance Management. A HFO's decision not to provide life-cycle control...

41 CFR 109-1.5304 - Deviations.

Code of Federal Regulations, 2012 CFR

2012-01-01

... High Risk Personal Property § 109-1.5304 Deviations. (a) Life cycle control determinations. When the HFO approves a contractor program containing controls, other than life cycle control consistent with... Secretary for Procurement and Assistance Management. A HFO's decision not to provide life-cycle control...

41 CFR 109-1.5304 - Deviations.

Code of Federal Regulations, 2011 CFR

2011-01-01

... High Risk Personal Property § 109-1.5304 Deviations. (a) Life cycle control determinations. When the HFO approves a contractor program containing controls, other than life cycle control consistent with... Secretary for Procurement and Assistance Management. A HFO's decision not to provide life-cycle control...

Development of computer software for pavement life cycle cost analysis.

DOT National Transportation Integrated Search

1988-01-01

The life cycle cost analysis program (LCCA) is designed to automate and standardize life cycle costing in Virginia. It allows the user to input information necessary for the analysis, and it then completes the calculations and produces a printed copy...

EVALUATING THE GREENNESS OF IONIC LIQUIDS VIA LIFE CYCLE ASSESSMENT

EPA Science Inventory

Ionic Liquids have been suggested as "greener" replacements to traditional solvents. However, the environmental impacts of the life cycle phases have not been studied. Such a "cradle to gate" Life Cycle Assessment (LCA) for comparing the environmental impact of various solvents...

Crash Attenuator Data Collection and Life Cycle Tool Development

DOT National Transportation Integrated Search

2014-06-14

This research study was aimed at data collection and development of a decision support tool for life cycle cost assessment of crash attenuators. Assessing arrenuator life cycle costs based on in-place expected costs and not just the initial cost enha...

LIFE CYCLE DESIGN FRAMEWORK AND DEMONSTRATION PROJECTS - PROFILES OF AT&T AND ALLIED SIGNAL

EPA Science Inventory

This document offers guidance and practical experience for integrating environmental considerations into product system development. Life cycle design seeks to minimize the environmental burden associated with a product's life cycle from raw materials acquisition through manufact...

Garvin Heath | NREL

Science.gov Websites

& Impacts Analysis Group in the Strategic Energy Analysis Center. Areas of Expertise Life cycle environmental impacts of energy technologies, including externalities Life cycle assessment Sustainability ;Life Cycle Assessment of a Parabolic Trough Concentrating Solar Power Plant and the Impacts of Key

From life cycle talking to taking action

EPA Science Inventory

The series of Life Cycle Management (LCM) conferences has aimed to create a platform for users and developers of life cycle assessment tools to share their experiences as they challenge traditional environmental management practices, which are narrowly confined (“gate-to-gate”) a...

User’s Guide for Naval Material Command’s Life Cycle Cost (FLEX) Model.

DTIC Science & Technology

1982-04-01

MATERIAL COMMANDl’S 3 LIFE CYCLE COST (FLEX) MODEL Icc FoIuhrInomto -- -- P ea eCo tc Pleale Cona, ______ _____-Thims document rc~ ofl 5C72 -lot REPORT...Material Command’s Life Cycle Cost (FLEX) Prep. 4/82 ___ Model ______________ ______________ 7. Author(s) S. Performing Organization Rapt. No. R. Dress (ESA...WANG 1I. Abstract (Limit: 200 words) The FLEX-9E life cycle cost comp~uter model is a user-oriented methodology accommodating most cost structures and

Reduced Order Methods for Prediction of Thermal-Acoustic Fatigue

NASA Technical Reports Server (NTRS)

Przekop, A.; Rizzi, S. A.

2004-01-01

The goal of this investigation is to assess the quality of high-cycle-fatigue life estimation via a reduced order method, for structures undergoing random nonlinear vibrations in a presence of thermal loading. Modal reduction is performed with several different suites of basis functions. After numerically solving the reduced order system equations of motion, the physical displacement time history is obtained by an inverse transformation and stresses are recovered. Stress ranges obtained through the rainflow counting procedure are used in a linear damage accumulation method to yield fatigue estimates. Fatigue life estimates obtained using various basis functions in the reduced order method are compared with those obtained from numerical simulation in physical degrees-of-freedom.

A Nonlinear Reduced Order Method for Prediction of Acoustic Fatigue

NASA Technical Reports Server (NTRS)

Przekop, Adam; Rizzi, Stephen A.

2006-01-01

The goal of this investigation is to assess the quality of high-cycle-fatigue life estimation via a reduced order method, for structures undergoing geometrically nonlinear random vibrations. Modal reduction is performed with several different suites of basis functions. After numerically solving the reduced order system equations of motion, the physical displacement time history is obtained by an inverse transformation and stresses are recovered. Stress ranges obtained through the rainflow counting procedure are used in a linear damage accumulation method to yield fatigue estimates. Fatigue life estimates obtained using various basis functions in the reduced order method are compared with those obtained from numerical simulation in physical degrees-of-freedom.

Incorporation of Carrier Phase Global Positioning System Measurements into the Navigation Reference System for Improved Performance

DTIC Science & Technology

1993-12-01

5-6 5.6.1 Large Cycle Slip Simulation ............................. 5-7 5.6.2 Small Cycle Slip Simulation ........................... 5-9...Appendix J. Small Cycle Slip Simulation Results ............................. J-1 Bibliography ........................................................ BIB-I...when subjected to large and small cycle slips. Results of the simulations indicate that the PNRS can provide an improved navigation solution over

Effect of KOH concentration on LEO cycle life of IPV nickel-hydrogen flight cell - Update II

NASA Technical Reports Server (NTRS)

Smithrick, John J.; Hall, Stephen W.

1992-01-01

An update of validation test results confirming the breakthrough in LEO cycle life of nickel-hydrogen cells containing 26 percent KOH electrolyte is presented. A breakthrough in the LEO cycle life of individual pressure vessel (IPV) nickel-hydrogen cells has been previously reported. The cycle life of boiler plate cells containing 26 percent potassium hydroxide (KOH) electrolyte was about 40,000 LEO cycles, compared to 3500 cycles for cells containing 31 percent KOH. The cycle regime was a stressful accelerated LEO, which consisted of a 27.5 min charge followed by a 17.5 min discharge (2X normal rate). The depth-of-discharge was 80 percent. Six 48-Ah Hughes recirculation design IPV nickel-hydrogen flight battery cells are being evaluated. Three of the cells contain 26 percent KOH (test cells), and three contain 31 percent KOH (control cells). They are undergoing real time LEO cycle life testing. The cycle regime is a 90-min LEO orbit consisting of a 54-min charge followed by a 36-min discharge. The depth-of-discharge is 80 percent. The cell temperature is maintained at 10 C. The three 31 percent KOH cells failed (cycles 3729, 4165, and 11355). One of the 26 percent KOH cells failed at cycle 15314. The other two 26 percent KOH cells were cycled for over 16,000 cycles during the continuing test.

Probabilistic Simulation for Combined Cycle Fatigue in Composites

NASA Technical Reports Server (NTRS)

Chamis, Christos C.

2010-01-01

A methodology to compute probabilistic fatigue life of polymer matrix laminated composites has been developed and demonstrated. Matrix degradation effects caused by long term environmental exposure and mechanical/thermal cyclic loads are accounted for in the simulation process. A unified time-temperature-stress dependent multifactor interaction relationship developed at NASA Glenn Research Center has been used to model the degradation/aging of material properties due to cyclic loads. The fast probability integration method is used to compute probabilistic distribution of response. Sensitivities of fatigue life reliability to uncertainties in the primitive random variables (e.g., constituent properties, fiber volume ratio, void volume ratio, ply thickness, etc.) computed and their significance in the reliability-based design for maximum life is discussed. The effect of variation in the thermal cyclic loads on the fatigue reliability for a (0/+/- 45/90)s graphite/epoxy laminate with a ply thickness of 0.127 mm, with respect to impending failure modes has been studied. The results show that, at low mechanical cyclic loads and low thermal cyclic amplitudes, fatigue life for 0.999 reliability is most sensitive to matrix compressive strength, matrix modulus, thermal expansion coefficient, and ply thickness. Whereas at high mechanical cyclic loads and high thermal cyclic amplitudes, fatigue life at 0.999 reliability is more sensitive to the shear strength of matrix, longitudinal fiber modulus, matrix modulus, and ply thickness.

Information system life-cycle and documentation standards, volume 1

NASA Technical Reports Server (NTRS)

Callender, E. David; Steinbacher, Jody

1989-01-01

The Software Management and Assurance Program (SMAP) Information System Life-Cycle and Documentation Standards Document describes the Version 4 standard information system life-cycle in terms of processes, products, and reviews. The description of the products includes detailed documentation standards. The standards in this document set can be applied to the life-cycle, i.e., to each phase in the system's development, and to the documentation of all NASA information systems. This provides consistency across the agency as well as visibility into the completeness of the information recorded. An information system is software-intensive, but consists of any combination of software, hardware, and operational procedures required to process, store, or transmit data. This document defines a standard life-cycle model and content for associated documentation.

48 CFR 211.274-1 - General.

Code of Federal Regulations, 2012 CFR

2012-10-01

... on leading practices and embraces open standards, DoD can— (a) Achieve lower life-cycle cost of item management and improve life-cycle property management; (b) Improve operational readiness; (c) Provide reliable accountability of property and asset visibility throughout the life cycle; and (d) Reduce the...

48 CFR 211.274-1 - General.

Code of Federal Regulations, 2011 CFR

2011-10-01

... on leading practices and embraces open standards, DoD can— (a) Achieve lower life-cycle cost of item management and improve life-cycle property management; (b) Improve operational readiness; (c) Provide reliable accountability of property and asset visibility throughout the life cycle; and (d) Reduce the...

48 CFR 211.274-1 - General.

Code of Federal Regulations, 2013 CFR

2013-10-01

... on leading practices and embraces open standards, DoD can— (a) Achieve lower life-cycle cost of item management and improve life-cycle property management; (b) Improve operational readiness; (c) Provide reliable accountability of property and asset visibility throughout the life cycle; and (d) Reduce the...

Reducing Life-Cycle Costs.

ERIC Educational Resources Information Center

Roodvoets, David L.

2003-01-01

Presents factors to consider when determining roofing life-cycle costs, explaining that costs do not tell the whole story; discussing components that should go into the decision (cost, maintenance, energy use, and environmental costs); and concluding that important elements in reducing life-cycle costs include energy savings through increased…

Software security checklist for the software life cycle

NASA Technical Reports Server (NTRS)

Gilliam, D. P.; Wolfe, T. L.; Sherif, J. S.

2002-01-01

A formal approach to security in the software life cycle is essential to protect corporate resources. However, little thought has been given to this aspect of software development. Due to its criticality, security should be integrated as a formal approach in the software life cycle.

EDITORIAL: THE INTERNATIONAL CONFERENCE ON LIFE CYCLE ASSESSMENT

EPA Science Inventory

This is a special issue of Journal of Life Cycle Assessment that includes selected papers from the Internatonal Conference and Exhibition on Life Cycle Assessment (InLCA). In April 2000, the EPA, with co-organizer IERE, held the InLCA conferencethat attracted over 265 attendees (...

LIFE CYCLE DESIGN OF AMORPHOUS SILICON PHOTOVOLTAIC MODULES

EPA Science Inventory

The life cycle design framework was applied to photovoltaic module design. The primary objective of this project was to develop and evaluate design metrics for assessing and guiding the Improvement of PV product systems. Two metrics were used to assess life cycle energy perform...

Test of US Federal Life Cycle Inventory Data Interoperability

EPA Science Inventory

Life cycle assessment practitioners must gather data from a variety of sources. For modeling activities in the US, practitioners may wish to use life cycle inventory data from public databases and libraries provided by US government entities. An exercise was conducted to test if ...

Holistic impact assessment and cost savings of rainwater harvesting at the watershed scale

EPA Science Inventory

We evaluated the impacts of domestic and agricultural rainwater harvesting (RWH) systems in three watersheds within the Albemarle-Pamlico river basin (southeastern U.S.) using life cycle assessment (LCA) and life cycle cost assessment. Life cycle impact assessment (LCIA) categori...

Educational Focuses in Organisational Life Cycles.

ERIC Educational Resources Information Center

Miller, Harry G.

1985-01-01

Presents four stages frequently associated with the stages of an organization's life cycle: experimentation, growth, maturity, and decline or stability. The author also demonstrates that the impact of employment and thus training related to organizational life cycles suggests a need for understanding the technical preparation required for…

PRODUCT LIFE-CYCLE ASSESSMENT: INVENTORY GUIDELINES AND PRINCIPLES

EPA Science Inventory

The Life Cycle Assessment (LCA) can be used as an objective technical tool to evaluate the environmental consequences of a product, process, or activity holistically, across its entire life cycle. omplete LCA can be viewed as consisting of three complementary components (1) the i...

1977 Nationwide Personal Transportation Study : a life cycle of travel by the American family

DOT National Transportation Integrated Search

1981-07-01

This report provides information about family trips and travel from the point of view of the family life cycle, using data from the 1977 Nationwide Personal Transportation Study. Daily travel characteristics of families in stages of four life cycles ...

Moving Carbon, Changing Earth: Bringing the Carbon Cycle to Life

NASA Astrophysics Data System (ADS)

Zabel, I.; Duggan-Haas, D.; Ross, R. M.; Stricker, B.; Mahowald, N. M.

2014-12-01

The carbon cycle presents challenges to researchers - in how to understand the complex interactions of fluxes, reservoirs, and systems - and to outreach professionals - in how to get across the complexity of the carbon cycle and still make it accessible to the public. At Cornell University and the Museum of the Earth in Ithaca, NY, researchers and outreach staff tackled these challenges together through a 2013 temporary museum exhibition: Moving Carbon, Changing Earth. Moving Carbon, Changing Earth introduced visitors to the world of carbon and its effect on every part of our lives. The exhibit was the result of the broader impacts portion of an NSF grant awarded to Natalie Mahowald, Professor in the Department of Earth and Atmospheric Sciences at Cornell University, who has been working with a team to improve simulations of regional and decadal variability in the carbon cycle. Within the exhibition, visitors used systems thinking to understand the distribution of carbon in and among Earth's systems, learning how (and how quickly or slowly) carbon moves between and within these systems, the relative scale of different reservoirs, and how carbon's movement changes climate and other environmental dynamics. Five interactive stations represented the oceans, lithosphere, atmosphere, biosphere, and a mystery reservoir. Puzzles, videos, real specimens, and an interview with Mahowald clarified and communicated the complexities of the carbon cycle. In this talk we'll present background information on Mahowald's research as well as photos of the exhibition and discussion of the components and motivations behind them, showing examples of innovative ways to bring a complex topic to life for museum visitors.

A Language Translator for a Computer Aided Rapid Prototyping System.

DTIC Science & Technology

1988-03-01

PROBLEM ................... S B. THE TRADITIONAL "WATERFALL LIFE CYCLE" .. ............... 14 C. RAPID PROTOTYPING...feature of everyday life for almost the entire industrialized world. Few governments or businesses function without the aid of computer systems. Com...engineering. B. TIE TRADITIONAL "WATERFALL LIFE CYCLE" I. Characteristics The traditional method of software engineering is the "waterfall life cycle

A Growth Model for the Academic Program Life Cycle (APLC): A Theoretical and Empirical Analysis. IR Applications, Volume 33

ERIC Educational Resources Information Center

Acquah, Edward H. K.

2012-01-01

The academic program life cycle (APLC) concept states each program's life flows through several stages: introduction, growth, maturity, and decline. A mixed-influence diffusion growth model is fitted to annual enrollment data on academic programs to analyze the factors determining progress of academic programs through their life cycles. The…

The numbers game: quantitative analysis of Neorickettsia sp. propagation through complex life cycle of its digenean host using real-time qPCR.

PubMed

Greiman, Stephen E; Tkach, Vasyl V

2016-07-01

Bacteria of the genus Neorickettsia are obligate intracellular endosymbionts of parasitic flukes (Digenea) and are passed through the entire complex life cycle of the parasite by vertical transmission. Several species of Neorickettsia are known to cause diseases in domestic animals, wildlife, and humans. Quantitative data on the transmission of the bacteria through the digenean life cycle is almost completely lacking. This study quantified for the first time the abundance of Neorickettsia within multiple stages of the life cycle of the digenean Plagiorchis elegans. Snails Lymnaea stagnalis collected from a pond in North Dakota were screened for the presence of digenean cercariae, which were subsequently tested for the presence of Neorickettsia. Three L. stagnalis were found shedding P. elegans cercariae infected with Neorickettsia. These snails were used to initiate three separate laboratory life cycles and obtain all life cycle stages for bacterial quantification. A quantitative real-time PCR assay targeting the GroEL gene was developed to enumerate Neorickettsia sp. within different stages of the digenean life cycle. The number of bacteria significantly increased throughout all stages, from eggs to adults. The two largest increases in number of bacteria occurred during the period from eggs to cercariae and from 6-day metacercariae to 48-h juvenile worms. These two periods seem to be the most important for Neorickettsia propagation through the complex digenean life cycle and maturation in the definitive host.

Fatigue and durability of Nitinol stents.

PubMed

Pelton, A R; Schroeder, V; Mitchell, M R; Gong, Xiao-Yan; Barney, M; Robertson, S W

2008-04-01

Nitinol self-expanding stents are effective in treating peripheral artery disease, including the superficial femoral, carotid, and renal arteries. However, fracture occurrences of up to 50% have been reported in some stents after one year. These stent fractures are likely due to in vivo cyclic displacements. As such, the cyclic fatigue and durability properties of Nitinol-based endovascular stents are discussed in terms of an engineering-based experimental testing program. In this paper, the combined effects of cardiac pulsatile fatigue and stent-vessel oversizing are evaluated for application to both stents and stent subcomponents. In particular, displacement-controlled fatigue tests were performed on stent-like specimens processed from Nitinol microtubing. Fatigue data were collected with combinations of simulated oversizing conditions and pulsatile cycles that were identified by computer modeling of the stent that mimic in vivo deformation conditions. These data are analyzed with non-linear finite element computations and are illustrated with strain-life and strain-based constant-life diagrams. The utility of this approach is demonstrated in conjunction with 10 million cycle pulsatile fatigue tests of Cordis SMART Control((R)) Nitinol self-expanding stents to calculate fatigue safety factors and thereby predict in vivo fatigue resistance. These results demonstrate the non-linear constant fatigue-life response of Nitinol stents, whereby, contrary to conventional engineering materials, the fatigue life of Nitinol is observed to increase with increasing mean strain.

Comparative muscle development of scyphozoan jellyfish with simple and complex life cycles.

PubMed

Helm, Rebecca R; Tiozzo, Stefano; Lilley, Martin K S; Lombard, Fabien; Dunn, Casey W

2015-01-01

Simple life cycles arise from complex life cycles when one or more developmental stages are lost. This raises a fundamental question - how can an intermediate stage, such as a larva, be removed, and development still produce a normal adult? To address this question, we examined the development in several species of pelagiid jellyfish. Most members of Pelagiidae have a complex life cycle with a sessile polyp that gives rise to ephyrae (juvenile medusae); but one species within Pelagiidae, Pelagia noctiluca, spends its whole life in the water column, developing from a larva directly into an ephyra. In many complex life cycles, adult features develop from cell populations that remain quiescent in larvae, and this is known as life cycle compartmentalization and may facilitate the evolution of direct life cycles. A second type of metamorphic processes, known as remodeling, occurs when adult features are formed through modification of already differentiated larval structures. We examined muscle morphology to determine which of these alternatives may be present in Pelagiidae. We first examined the structure and development of polyp and ephyra musculature in Chrysaora quinquecirrha, a close relative of P. noctiluca with a complex life cycle. Using phallotoxin staining and confocal microscopy, we verified that polyps have four to six cord muscles that persist in strobilae and discovered that cord muscles is physically separated from ephyra muscle. When cord muscle is removed from ephyra segments, normal ephyra muscle still develops. This suggests that polyp cord muscle is not necessary for ephyra muscle formation. We also found no evidence of polyp-like muscle in P. noctiluca. In both species, we discovered that ephyra muscle arises de novo in a similar manner, regardless of the life cycle. The separate origins of polyp and ephyra muscle in C. quinquecirrha and the absence of polyp-like muscle in P. noctiluca suggest that polyp muscle is not remodeled to form ephyra muscle in Pelagiidae. Life cycle stages in Scyphozoa may instead be compartmentalized. Because polyp muscle is not directly remodeled, this may have facilitated the loss of the polyp stage in the evolution of P. noctiluca.

A Darwinian approach to the origin of life cycles with group properties.

PubMed

Rashidi, Armin; Shelton, Deborah E; Michod, Richard E

2015-06-01

A selective explanation for the evolution of multicellular organisms from unicellular ones requires knowledge of both selective pressures and factors affecting the response to selection. Understanding the response to selection is particularly challenging in the case of evolutionary transitions in individuality, because these transitions involve a shift in the very units of selection. We develop a conceptual framework in which three fundamental processes (growth, division, and splitting) are the scaffold for unicellular and multicellular life cycles alike. We (i) enumerate the possible ways in which these processes can be linked to create more complex life cycles, (ii) introduce three genes based on growth, division and splitting that, acting in concert, determine the architecture of the life cycles, and finally, (iii) study the evolution of the simplest five life cycles using a heuristic model of coupled ordinary differential equations in which mutations are allowed in the three genes. We demonstrate how changes in the regulation of three fundamental aspects of colonial form (cell size, colony size, and colony cell number) could lead unicellular life cycles to evolve into primitive multicellular life cycles with group properties. One interesting prediction of the model is that selection generally favors cycles with group level properties when intermediate body size is associated with lowest mortality. That is, a universal requirement for the evolution of group cycles in the model is that the size-mortality curve be U-shaped. Furthermore, growth must decelerate with size. Copyright © 2015 Elsevier Inc. All rights reserved.

Earth Without Life: A Systems Model of a Global Abiotic Nitrogen Cycle

NASA Astrophysics Data System (ADS)

Laneuville, M.; Kameya, M.; Cleaves, H. J.

2017-07-01

N is the major component of the atmosphere and plays important roles in biochemistry. Presently, the surface N-cycle is dominated by biology. However, before the origin of life, abiotic N-cycling would have set the stage for the origin of life.

LIFE CYCLE IMPACT ASSESSMENT AN INTRODUCTION AND INTERNATIONAL UPDATE

EPA Science Inventory

Research within the field of Life Cycle Impact Assessment (LCIA) has greatly improved since the work of Heijungs and Guinee in 1992. Within the UNEP / SETAC Life Cycle Initiative an effort is underway to provide recommendations about the direction of research and selection of LC...

Achieving Our Environmental Sustainability Goals: The Opportunities and Pitfalls of Applying Life Cycle Thinking

EPA Science Inventory

An increasing number of people around the world are beginning to realize that a systems approach, such as life cycle thinking, is necessary to truly achieve environmental sustainability. Without the holistic perspective that life cycle thinking provides, our actions risk leading ...

Dealing with Emergy Algebra in the Life Cycle Assessment Framework

EPA Science Inventory

The Life Cycle Inventory (LCI) represents one of the four steps of the Life Cycle Assessment (LCA) methodology, which is a standardized procedure (ISO 14040:2006) to estimate the environmental impacts generated by the production, use and disposal of goods and services. In this co...

Comparison of energy-based indicators used in life cycle assessment tools for buildings

EPA Science Inventory

Traditionally, building rating systems focused on, among others, energy used during operational stage. Recently, there is a strong push by these rating systems to include the life cycle energy use of buildings, particularly using Life Cycle Assessment (LCA), by offering credits t...

10 CFR 436.24 - Uncertainty analyses.

Code of Federal Regulations, 2011 CFR

2011-01-01

... Procedures for Life Cycle Cost Analyses § 436.24 Uncertainty analyses. If particular items of cost data or... impact of uncertainty on the calculation of life cycle cost effectiveness or the assignment of rank order... and probabilistic analysis. If additional analysis casts substantial doubt on the life cycle cost...

10 CFR 436.24 - Uncertainty analyses.

Code of Federal Regulations, 2013 CFR

2013-01-01

... Procedures for Life Cycle Cost Analyses § 436.24 Uncertainty analyses. If particular items of cost data or... impact of uncertainty on the calculation of life cycle cost effectiveness or the assignment of rank order... and probabilistic analysis. If additional analysis casts substantial doubt on the life cycle cost...

10 CFR 436.24 - Uncertainty analyses.

Code of Federal Regulations, 2014 CFR

2014-01-01

... Procedures for Life Cycle Cost Analyses § 436.24 Uncertainty analyses. If particular items of cost data or... impact of uncertainty on the calculation of life cycle cost effectiveness or the assignment of rank order... and probabilistic analysis. If additional analysis casts substantial doubt on the life cycle cost...

10 CFR 436.24 - Uncertainty analyses.

Code of Federal Regulations, 2012 CFR

2012-01-01

... Procedures for Life Cycle Cost Analyses § 436.24 Uncertainty analyses. If particular items of cost data or... impact of uncertainty on the calculation of life cycle cost effectiveness or the assignment of rank order... and probabilistic analysis. If additional analysis casts substantial doubt on the life cycle cost...

LIFE-CYCLE IMPACT ASSESSMENT DEMONSTRATION FOR THE BGU-24

EPA Science Inventory

The primary goal of this project was to develop and demonstrate a life-cycle impact assessment (LCIA) approach using existing life-cycle inventory (LCI) data on one of the propellants, energetics, and pyrotechnic (PEP) materials of interest to the U.S. Department of Defense (DoD)...

A Game to Teach the Life Cycles of Fungi

ERIC Educational Resources Information Center

Blum, Abraham

1976-01-01

Presented is a biological game utilized to teach fungi life cycles to secondary biology students. The game is designed to overcome difficulties of correlating schematic drawings with images seen through the microscope, correlating life cycles of fungi and host, and understanding cyclic development of fungi. (SL)

10 CFR 436.11 - Definitions.

Code of Federal Regulations, 2010 CFR

2010-01-01

... Life Cycle Cost Analyses § 436.11 Definitions. As used in this subpart— Base Year means the fiscal year in which a life cycle cost analysis is conducted. Building energy system means an energy conservation... building that improve energy efficiency and are life cycle cost effective and that involve energy...

Integrated Metrics for Improving the Life Cycle Approach to Assessing Product System Sustainability

EPA Science Inventory

Life cycle approaches are critical for identifying and managing to reduce burdens in the sustainability of product systems. While these methods can indicate potential environmental impacts of a product, current Life Cycle Assessment (LCA) methods fail to integrate the multiple im...

The Process of Life Cycle Cost Analysis: Projecting Economic Consequences of Design Decisions

ERIC Educational Resources Information Center

AIA Journal, 1976

1976-01-01

Life-cycle cost analysis deals with both present and future costs and attempts to relate the two as a basis for making decisions. This article lays the groundwork for a better understanding of the techniques of life-cycle cost analysis. (Author/MLF)

THE EPA'S EMERGING FOCUS ON LIFE CYCLE ASSESSMENT

EPA Science Inventory

EPA has been actively engaged in LCA research since 1990 to help advance the methodology and application of life cycle thinking in decision making. Across the Agency consideration of the life cycle concept is increasing in the development of policies and programs. A major force i...

Concept of Operations Visualization in Support of Ares I Production

NASA Technical Reports Server (NTRS)

Chilton, James H.; Smith, Daid Alan

2008-01-01

Boeing was selected in 2007 to manufacture Ares I Upper Stage and Instrument Unit according to NASA's design which would require the use of the latest manufacturing and integration processes to meet NASA budget and schedule targets. Past production experience has established that the majority of the life cycle cost is established during the initial design process. Concept of Operations (CONOPs) visualizations/simulations help to reduce life cycle cost during the early design stage. Production and operation visualizations can reduce tooling, factory capacity, safety, and build process risks while spreading program support across government, academic, media and public constituencies. The NASA/Boeing production visualization (DELMIA; Digital Enterprise Lean Manufacturing Interactive Application) promotes timely, concurrent and collaborative producibility analysis (Boeing)while supporting Upper Stage Design Cycles (NASA). The DELMIA CONOPs visualization reduced overall Upper Stage production flow time at the manufacturing facility by over 100 man-days to 312.5 man-days and helped to identify technical access issues. The NASA/Boeing Interactive Concept of Operations (ICON) provides interactive access to Ares using real mission parameters, allows users to configure the mission which encourages ownership and identifies areas for improvement, allows mission operations or spacecraft detail to be added as needed, and provides an effective, low coast advocacy, outreach and education tool.

Integration and scaling of UV-B radiation effects on plants: from molecular interactions to whole plant responses.

PubMed

Suchar, Vasile Alexandru; Robberecht, Ronald

2016-07-01

A process based model integrating the effects of UV-B radiation to molecular level processes and their consequences to whole plant growth and development was developed from key parameters in the published literature. Model simulations showed that UV-B radiation induced changes in plant metabolic and/or photosynthesis rates can result in plant growth inhibitions. The costs of effective epidermal UV-B radiation absorptive compounds did not result in any significant changes in plant growth, but any associated metabolic costs effectively reduced the potential plant biomass. The model showed significant interactions between UV-B radiation effects and temperature and any factor leading to inhibition of photosynthetic production or plant growth during the midday, but the effects were not cumulative for all factors. Vegetative growth were significantly delayed in species that do not exhibit reproductive cycles during a growing season, but vegetative growth and reproductive yield in species completing their life cycle in one growing season did not appear to be delayed more than 2-5 days, probably within the natural variability of the life cycles for many species. This is the first model to integrate the effects of increased UV-B radiation through molecular level processes and their consequences to whole plant growth and development.

Filling Open Screw Holes in the Area of Metaphyseal Comminution Does Not Affect Fatigue Life of the Synthes Variable Angle Distal Femoral Locking Plate in the AO/OTA 33-A3 Fracture Model.

PubMed

Grau, Luis; Collon, Kevin; Alhandi, Ali; Kaimrajh, David; Varon, Maria; Latta, Loren; Vilella, Fernando

2018-06-01

The aim of this study is to evaluate the biomechanical effect of filling locking variable angle (VA) screw holes at the area of metaphyseal fracture comminution in a Sawbones® (Sawbones USA, Vashon, Washington) model (AO/OTA 33A-3 fracture) using a Synthes VA locking compression plate (LCP) (Depuy Synthes, Warsaw, Indiana). Seven Sawbones® femur models had a Synthes VA-LCP placed as indicated by the manufacturers technique. A 4cm osteotomy was then created to simulate an AO/OTA 33-A3 femoral fracture pattern with metaphyseal comminution. The control group consisted of four constructs in which the open screw holes at the area of comminution were left unfilled; the experimental group consisted of three constructs in which the VA screw holes were filled with locking screws. One of the control constructs was statically loaded to failure at a rate of 5mm/min. A value equal to 75% of the ultimate load to failure was used as the loading force for fatigue testing of 250,000 cycles at 3Hz. Cycles to failure was recorded for each construct and averages were compared between groups. The average number of cycles to failure in the control and experimental groups were 37524±8187 and 43304±23835, respectively (p=0.72). No significant difference was observed with respect to cycles to failure or mechanism of failure between groups. In all constructs in both the control and experimental groups, plate failure reproducibly occurred with cracks through the variable angle holes in the area of bridged comminution. The Synthes VA-LCP in a simulated AO/OTA 33-A3 comminuted metaphyseal femoral fracture fails in a reproducible manner at the area of comminution through the "honeycomb" VA screw holes. Filling open VA screw holes at the site of comminution with locking screws does not increase fatigue life of the Synthes VA-LCP in a simulated AO/OTA 33-A3 distal femoral fracture. Further studies are necessary to determine whether use of this particular plate is contraindicated when bridging distal femoral fractures with metaphyseal comminution.

NASA Lewis advanced IPV nickel-hydrogen technology

NASA Technical Reports Server (NTRS)

Smithrick, John J.; Britton, Doris L.

1993-01-01

Individual pressure vessel (IPV) nickel-hydrogen technology was advanced at NASA Lewis and under Lewis contracts. Some of the advancements are as follows: to use 26 percent potassium hydroxide electrolyte to improve cycle life and performance, to modify the state of the art cell design to eliminate identified failure modes and further improve cycle life, and to develop a lightweight nickel electrode to reduce battery mass, hence reduce launch and/or increase satellite payload. A breakthrough in the LEO cycle life of individual pressure vessel nickel-hydrogen battery cells was reported. The cycle life of boiler plate cells containing 26 percent KOH electrolyte was about 40,000 accelerated LEO cycles at 80 percent DOD compared to 3,500 cycles for cells containing 31 percent KOH. Results of the boiler plate cell tests have been validated at NWSC, Crane, Indiana. Forty-eight ampere-hour flight cells containing 26 and 31 percent KOH have undergone real time LEO cycle life testing at an 80 percent DOD, 10 C. The three cells containing 26 percent KOH failed on the average at cycle 19,500. The three cells containing 31 percent KOH failed on the average at cycle 6,400. Validation testing of NASA Lewis 125 Ah advanced design IPV nickel-hydrogen flight cells is also being conducted at NWSC, Crane, Indiana under a NASA Lewis contract. This consists of characterization, storage, and cycle life testing. There was no capacity degradation after 52 days of storage with the cells in the discharged state, on open circuit, 0 C, and a hydrogen pressure of 14.5 psia. The catalyzed wall wick cells have been cycled for over 22,694 cycles with no cell failures in the continuing test. All three of the non-catalyzed wall wick cells failed (cycles 9,588; 13,900; and 20,575). Cycle life test results of the Fibrex nickel electrode has demonstrated the feasibility of an improved nickel electrode giving a higher specific energy nickel-hydrogen cell. A nickel-hydrogen boiler plate cell using an 80 mil thick, 90 percent porous Fibrex nickel electrode has been cycled for 10,000 cycles at 40 percent DOD.

Fractographic evaluation of creep effects on strain-controlled fatigue-cracking of AISI 304LC and 316 stainless steel

NASA Technical Reports Server (NTRS)

Oldrieve, R. E.

1978-01-01

Analysis of high temperature low cycle fatigue of AISI 304LC and 316 stainless steels by the method of strainrange partitioning results in four separate strainrange versus life relationships, depending upon the way in which creep-strain and plastic strain are combined within a cycle. Fractography is used in this investigation of the creep-fatigue interaction associated with these cycles. The PP and PC-cycle fractures were transgranular. The PC-cycle resulted in fewer cycles of initiation and shorter total cyclic life for the same applied inelastic strainrange. The CC-cycle had mixed transgranular and intergranular fracture, fewer cycles of initiation and shorter cycle life than PP or PC. The CP-cycle had fully integranular cracking, and failed in fewer cycles than were required for cracks to initate for PP,PC, and CC.

Assessing reliability of fatigue indicator parameters for small crack growth via a probabilistic framework

NASA Astrophysics Data System (ADS)

Rovinelli, Andrea; Guilhem, Yoann; Proudhon, Henry; Lebensohn, Ricardo A.; Ludwig, Wolfgang; Sangid, Michael D.

2017-06-01

Microstructurally small cracks exhibit large variability in their fatigue crack growth rate. It is accepted that the inherent variability in microstructural features is related to the uncertainty in the growth rate. However, due to (i) the lack of cycle-by-cycle experimental data, (ii) the complexity of the short crack growth phenomenon, and (iii) the incomplete physics of constitutive relationships, only empirical damage metrics have been postulated to describe the short crack driving force metric (SCDFM) at the mesoscale level. The identification of the SCDFM of polycrystalline engineering alloys is a critical need, in order to achieve more reliable fatigue life prediction and improve material design. In this work, the first steps in the development of a general probabilistic framework are presented, which uses experimental result as an input, retrieves missing experimental data through crystal plasticity (CP) simulations, and extracts correlations utilizing machine learning and Bayesian networks (BNs). More precisely, experimental results representing cycle-by-cycle data of a short crack growing through a beta-metastable titanium alloy, VST-55531, have been acquired via phase and diffraction contrast tomography. These results serve as an input for FFT-based CP simulations, which provide the micromechanical fields influenced by the presence of the crack, complementing the information available from the experiment. In order to assess the correlation between postulated SCDFM and experimental observations, the data is mined and analyzed utilizing BNs. Results show the ability of the framework to autonomously capture relevant correlations and the equivalence in the prediction capability of different postulated SCDFMs for the high cycle fatigue regime.

Intimacy and the life cycle in the marital relationships of the Scottish elite during the long eighteenth century.

PubMed

Barclay, Katie

2011-01-01

Traditionally marriage has been treated as one step in the life cycle, between youth and old age, singleness and widowhood. Yet an approach to the life cycle that treats marriage as a single step in a person's life is overly simplistic. During the eighteenth century many marriages were of considerable longevity during which time couples aged together and power dynamics within the home were frequently renegotiated to reflect changing circumstances. This study explores how intimacy developed and changed over the life cycle of marriage and what this meant for power, through a study of the correspondence of two elite Scottish couples.

Visceral Leishmaniasis on the Indian Subcontinent: Modelling the Dynamic Relationship between Vector Control Schemes and Vector Life Cycles.

PubMed

Poché, David M; Grant, William E; Wang, Hsiao-Hsuan

2016-08-01

Visceral leishmaniasis (VL) is a disease caused by two known vector-borne parasite species (Leishmania donovani, L. infantum), transmitted to man by phlebotomine sand flies (species: Phlebotomus and Lutzomyia), resulting in ≈50,000 human fatalities annually, ≈67% occurring on the Indian subcontinent. Indoor residual spraying is the current method of sand fly control in India, but alternative means of vector control, such as the treatment of livestock with systemic insecticide-based drugs, are being evaluated. We describe an individual-based, stochastic, life-stage-structured model that represents a sand fly vector population within a village in India and simulates the effects of vector control via fipronil-based drugs orally administered to cattle, which target both blood-feeding adults and larvae that feed on host feces. Simulation results indicated efficacy of fipronil-based control schemes in reducing sand fly abundance depended on timing of drug applications relative to seasonality of the sand fly life cycle. Taking into account cost-effectiveness and logistical feasibility, two of the most efficacious treatment schemes reduced population peaks occurring from April through August by ≈90% (applications 3 times per year at 2-month intervals initiated in March) and >95% (applications 6 times per year at 2-month intervals initiated in January) relative to no control, with the cumulative number of sand fly days occurring April-August reduced by ≈83% and ≈97%, respectively, and more specifically during the summer months of peak human exposure (June-August) by ≈85% and ≈97%, respectively. Our model should prove useful in a priori evaluation of the efficacy of fipronil-based drugs in controlling leishmaniasis on the Indian subcontinent and beyond.

The Life Cycle of Images: Revisiting the Ethical Treatment of the Art Therapy Image

ERIC Educational Resources Information Center

Hinz, Lisa D.

2013-01-01

Using the metaphor of the human life cycle, the author of this viewpoint suggests that consideration of the birth, life, and death of images made in art therapy may promote a new perspective on their ethical treatment. A developmental view of images encourages art therapists to see art images as living entities that undergo a natural life cycle.…

The Life Cycle of Everyday Stuff.

ERIC Educational Resources Information Center

Reeske, Mike; Ireton, Shirley Watt

Life cycle assessment is an important tool for technology planning as solid waste disposal options dwindle and energy prices continue to increase. This guide investigates the life cycles of products. The activities in this book are suitable for secondary earth science, environmental science, physical science, or integrated science lessons. The…

A life cycle greenhouse gas inventory of a tree production system

Treesearch

Alissa Kendall; E. Gregory McPherson

2012-01-01

PurposeThis study provides a detailed, process-based life cycle greenhouse gas (GHG) inventory of an ornamental tree production system for urban forestry. The success of large-scale tree planting initiatives for climate protection depends on projects being net sinks for CO2 over their entire life cycle....

Sustainability Analysis | Energy Analysis | NREL

Science.gov Websites

environmental, life-cycle, climate, and other impacts of renewable energy technologies. Photo of a man viewing a energy choices within the complex web of connections between energy and water. Life Cycle Assessment Harmonization Our life cycle assessment harmonization provides lenders, utility executives, and lawmakers with

10 CFR 434.607 - Life cycle cost analysis criteria.

Code of Federal Regulations, 2013 CFR

2013-01-01

... 10 Energy 3 2013-01-01 2013-01-01 false Life cycle cost analysis criteria. 434.607 Section 434.607 Energy DEPARTMENT OF ENERGY ENERGY CONSERVATION ENERGY CODE FOR NEW FEDERAL COMMERCIAL AND MULTI-FAMILY HIGH RISE RESIDENTIAL BUILDINGS Building Energy Compliance Alternative § 434.607 Life cycle cost...

10 CFR 434.607 - Life cycle cost analysis criteria.

Code of Federal Regulations, 2014 CFR

2014-01-01

... 10 Energy 3 2014-01-01 2014-01-01 false Life cycle cost analysis criteria. 434.607 Section 434.607 Energy DEPARTMENT OF ENERGY ENERGY CONSERVATION ENERGY CODE FOR NEW FEDERAL COMMERCIAL AND MULTI-FAMILY HIGH RISE RESIDENTIAL BUILDINGS Building Energy Compliance Alternative § 434.607 Life cycle cost...

10 CFR 434.607 - Life cycle cost analysis criteria.

Code of Federal Regulations, 2012 CFR

2012-01-01

... 10 Energy 3 2012-01-01 2012-01-01 false Life cycle cost analysis criteria. 434.607 Section 434.607 Energy DEPARTMENT OF ENERGY ENERGY CONSERVATION ENERGY CODE FOR NEW FEDERAL COMMERCIAL AND MULTI-FAMILY HIGH RISE RESIDENTIAL BUILDINGS Building Energy Compliance Alternative § 434.607 Life cycle cost...

Enhancing TSM&O strategies through life cycle benefit/cost analysis : life cycle benefit/cost analysis & life cycle assessment of adaptive traffic control systems and ramp metering systems.

DOT National Transportation Integrated Search

2015-05-01

The research team developed a comprehensive Benefit/Cost (B/C) analysis framework to evaluate existing and anticipated : intelligent transportation system (ITS) strategies, particularly, adaptive traffic control systems and ramp metering systems, : i...

LIFE CYCLE BASED STUDIES ON BIOETHANOL FUEL FOR SUSTAINABLE TRANSPORTATION: A LITERATURE REVIEW

EPA Science Inventory

A literature search was conducted and revealed 45 publications (1996-2005) that compare bio-ethanol systems to conventional fuel on a life-cycle basis, or using life cycle assessment. Feedstocks, such as sugar beets, wheat, potato, sugar cane, and corn, have been investigated in...

Life cycle assessment of a commercial rainwater harvesting system compared with a municipal water supply system

EPA Science Inventory

Building upon previously published life cycle assessment (LCA) methodologies, we conducted an LCA of a commercial rainwater harvesting (RWH) system and compared it to a municipal water supply (MWS) system adapted to Washington, D.C. Eleven life cycle impact assessment (LCIA) indi...

LIFE-CYCLE IMPACT ASSESSMENT DEMONSTRATION FOR THE GBU-24

EPA Science Inventory

The primary goal of this project was to develop and demonstrate a life-cycle impact assessment (LCIA) approach using existing life-cycle inventory (LCI) data on one of the propellants, energetics, and pyro-technic (PEP) materials of interest to the U.S. Department of Defense (DoD...

Life-cycle energy and emissions inventories for motorcycles, diesel automobiles, school buses, electric buses, Chicago rail, and New York City rail

DOT National Transportation Integrated Search

2009-05-01

The development of life-cycle energy and emissions factors for passenger transportation modes : is critical for understanding the total environmental costs of travel. Previous life-cycle studies : have focused on the automobile given its dominating s...

LIFE CYCLE DESIGN OF AIR INTAKE MANIFOLDS; PHASE I: 2.0 L FORD CONTOUR AIR INTAKE MANIFOLD

EPA Science Inventory

The project team applied the life cycle design methodology to the design analysis of three alternative air intake manifolds: a sand cast aluminum, brazed aluminum tubular, and nylon composite. The design analysis included a life cycle inventory analysis, environmental regulatory...

THE INTERNATIONAL WORKSHOP ON ELECTRICITY DATA FOR LIFE CYCLE INVENTORIES

EPA Science Inventory

A three day workshop was held in October 2001 to discuss life cycle inventory data for electricity production. Electricity was selected as the topic for discussion since it features very prominently in the LCA results for most product life cycles, yet there is no consistency in h...

10 CFR 436.13 - Presuming cost-effectiveness results.

Code of Federal Regulations, 2010 CFR

2010-01-01

... Methodology and Procedures for Life Cycle Cost Analyses § 436.13 Presuming cost-effectiveness results. (a) If... life cycle cost-effective without further analysis. (b) A Federal agency may presume that an investment in an energy or water conservation measure retrofit to an existing Federal building is not life cycle...

76 FR 34271 - Hewlett Packard, Global Parts Supply Chain, Global Product Life Cycles Management Unit, Including...

Federal Register 2010, 2011, 2012, 2013, 2014

2011-06-13

... DEPARTMENT OF LABOR Employment and Training Administration [TA-W-74,671] Hewlett Packard, Global Parts Supply Chain, Global Product Life Cycles Management Unit, Including Teleworkers Reporting to... Supply Chain, Global Product Life Cycles Management Unit, including teleworkers reporting to Houston...