Science.gov

Sample records for cost optimal heat

  1. Optimization of Heat Exchangers

    SciTech Connect

    Ivan Catton

    2010-10-01

    The objective of this research is to develop tools to design and optimize heat exchangers (HE) and compact heat exchangers (CHE) for intermediate loop heat transport systems found in the very high temperature reator (VHTR) and other Generation IV designs by addressing heat transfer surface augmentation and conjugate modeling. To optimize heat exchanger, a fast running model must be created that will allow for multiple designs to be compared quickly. To model a heat exchanger, volume averaging theory, VAT, is used. VAT allows for the conservation of mass, momentum and energy to be solved for point by point in a 3 dimensional computer model of a heat exchanger. The end product of this project is a computer code that can predict an optimal configuration for a heat exchanger given only a few constraints (input fluids, size, cost, etc.). As VAT computer code can be used to model characteristics )pumping power, temperatures, and cost) of heat exchangers more quickly than traditional CFD or experiment, optimization of every geometric parameter simultaneously can be made. Using design of experiment, DOE and genetric algorithms, GE, to optimize the results of the computer code will improve heat exchanger disign.

  2. Optimizing the Costs of Solid Sorbent-Based CO2 Capture Process Through Heat Integration

    SciTech Connect

    Sjostrom, Sharon

    2016-03-18

    The focus of this project was the ADAsorb™ CO2 Capture Process, a temperature-swing adsorption process that incorporates a three-stage fluidized bed as the adsorber and a single-stage fluidized bed as the regenerator. ADAsorb™ system was designed, fabricated, and tested under DOE award DEFE0004343. Two amine-based sorbents were evaluated in conjunction with the ADAsorb™ process: “BN”, an ion-exchange resin; and “OJ”, a metal organic framework (MOF) sorbent. Two cross heat exchanger designs were evaluated for use between the adsorber and regenerator: moving bed and fluidized bed. The fluidized bed approach was rejected fairly early in the project because the additional electrical load to power blowers or fans to overcome the pressure drop required for fluidization was estimated to be nominally three times the electrical power that could be generated from the steam saved through the use of the cross heat exchanger. The Energy Research Center at Lehigh University built and utilized a process model of the ADAsorb™ capture process and integrated this model into an existing model of a supercritical PC power plant. The Lehigh models verified that, for the ADAsorb™ system, the largest contributor to parasitic power was lost electrical generation, which was primarily electric power which the host plant could not generate due to the extraction of low pressure (LP) steam for sorbent heating, followed by power for the CO2 compressor and the blower or fan power required to fluidize the adsorber and regenerator. Sorbent characteristics such as the impacts of moisture uptake, optimized adsorption and regeneration temperature, and sensitivity to changes in pressure were also included in the modeling study. Results indicate that sorbents which adsorb more than 1-2% moisture by weight are unlikely to be cost competitive unless they have an extremely high CO2 working capacity that well exceeds 15% by weight. Modeling also revealed

  3. Heliostat cost optimization study

    NASA Astrophysics Data System (ADS)

    von Reeken, Finn; Weinrebe, Gerhard; Keck, Thomas; Balz, Markus

    2016-05-01

    This paper presents a methodology for a heliostat cost optimization study. First different variants of small, medium sized and large heliostats are designed. Then the respective costs, tracking and optical quality are determined. For the calculation of optical quality a structural model of the heliostat is programmed and analyzed using finite element software. The costs are determined based on inquiries and from experience with similar structures. Eventually the levelised electricity costs for a reference power tower plant are calculated. Before each annual simulation run the heliostat field is optimized. Calculated LCOEs are then used to identify the most suitable option(s). Finally, the conclusions and findings of this extensive cost study are used to define the concept of a new cost-efficient heliostat called `Stellio'.

  4. Cost optimization in anaesthesia.

    PubMed

    Bauer, M; Bach, A; Martin, E; Böttiger, B W

    2001-04-01

    As a result of the progress which has been made in medicine and technology and the increase in morbidity associated this demographic development, the need and thus the costs for medical care have increased as well. The financial resources which are available for medical care, however, are still limited and hence the funds which are available must be distributed more efficiently. Cost optimisation measures can help make better use of the profitability reserves in hospitals. The authors show how costs can be optimised in the anaesthesiology department of a clinic. Pharmacoeconomic evaluation of the new inhalation anaesthetics shows an example of how the cost structures in anaesthesia can be made more obvious and potential ways savings be implemented. To reduce material and personnel costs, a more rational means of internal process management is presented. According to cost-effectiveness analysis, medications are not divided into the categories inexpensive and expensive but rather cost-effective or non-cost-effective. By selecting a cost-effective drug it is possible to reduce cost at a hospital. For example, sevoflurane at a fresh gas flow of below 3 l/min has been shown to be a cost-effective inhalation anaesthetic which, in terms of the economics, is also superior to intravenous anaesthesia with propofol. In addition to these measures of reducing material costs, other examples are given of how personnel costs can be reduced by optimising work procedures: e.g. effective operating theatre co-ordination, short switchover times by overlapping anaesthesia induction and the use of multifunctional personnel. The gain in productivity which is a result of these measures can positively affect profits, and by optimising the organisation of procedures to shorten the times required to carry out a procedure, costs can be reduced.

  5. Renewable Energy Planning: Multiparametric Cost Optimization; Preprint

    SciTech Connect

    Walker, A.

    2008-05-01

    This paper describes a method for determining the combination of renewable energy technologies that minimize life-cycle cost at a facility, often with a specified goal regarding percent of energy use from renewable sources. Technologies include: photovoltaics (PV); wind; solar thermal heat and electric; solar ventilation air preheating; solar water heating; biomass heat and electric (combustion, gasification, pyrolysis, anaerobic digestion); and daylighting. The method rests upon the National Renewable Energy Laboratory's (NREL's) capabilities in characterization of technology cost and performance, geographic information systems (GIS) resource assessment, and life-cycle cost analysis. The paper discusses how to account for the way candidate technologies interact with each other, and the solver routine used to determine the combination that minimizes life-cycle cost. Results include optimal sizes of each technology, initial cost, operating cost, and life-cycle cost, including incentives from utilities or governments. Results inform early planning to identify and prioritize projects at a site for subsequent engineering and economic feasibility study.

  6. Wind Electrolysis: Hydrogen Cost Optimization

    SciTech Connect

    Saur, G.; Ramsden, T.

    2011-05-01

    This report describes a hydrogen production cost analysis of a collection of optimized central wind based water electrolysis production facilities. The basic modeled wind electrolysis facility includes a number of low temperature electrolyzers and a co-located wind farm encompassing a number of 3MW wind turbines that provide electricity for the electrolyzer units.

  7. Heat Sink Design and Optimization

    DTIC Science & Technology

    2015-12-01

    hot surfaces to cooler ambient air. Typically, the fins are oriented in a way to permit a natural convection air draft to flow upward through...main objective. Heat transfer from the heat sink consists of radiation and convection from both the intra-fin passages and the unshielded...Natural convection Radiation Design Modeling Optimization 16. SECURITY CLASSIFICATION OF: 17

  8. Low cost uniform heat source

    NASA Technical Reports Server (NTRS)

    Smith, R. B.; Prok, G. M.

    1973-01-01

    Electrically powered heat source was developed for ground simulation of isotope heat-source assembly in Brayton power system. Heat source, which operates on ordinary 110 vac power, consists of tungsten filament heating element wound onto a spirally grooved boron nitride core and inserted in a hollowed-out graphite hexahedron.

  9. Optimizing Sustainable Geothermal Heat Extraction

    NASA Astrophysics Data System (ADS)

    Patel, Iti; Bielicki, Jeffrey; Buscheck, Thomas

    2016-04-01

    Geothermal heat, though renewable, can be depleted over time if the rate of heat extraction exceeds the natural rate of renewal. As such, the sustainability of a geothermal resource is typically viewed as preserving the energy of the reservoir by weighing heat extraction against renewability. But heat that is extracted from a geothermal reservoir is used to provide a service to society and an economic gain to the provider of that service. For heat extraction used for market commodities, sustainability entails balancing the rate at which the reservoir temperature renews with the rate at which heat is extracted and converted into economic profit. We present a model for managing geothermal resources that combines simulations of geothermal reservoir performance with natural resource economics in order to develop optimal heat mining strategies. Similar optimal control approaches have been developed for managing other renewable resources, like fisheries and forests. We used the Non-isothermal Unsaturated-saturated Flow and Transport (NUFT) model to simulate the performance of a sedimentary geothermal reservoir under a variety of geologic and operational situations. The results of NUFT are integrated into the optimization model to determine the extraction path over time that maximizes the net present profit given the performance of the geothermal resource. Results suggest that the discount rate that is used to calculate the net present value of economic gain is a major determinant of the optimal extraction path, particularly for shallower and cooler reservoirs, where the regeneration of energy due to the natural geothermal heat flux is a smaller percentage of the amount of energy that is extracted from the reservoir.

  10. Reducing home heating and cooling costs

    SciTech Connect

    Not Available

    1994-07-01

    This report is in response to a request from the House Committee on Energy and Commerce that the Energy Information Administration (EIA) undertake a neutral, unbiased analysis of the cost, safety, and health and environmental effects of the three major heating fuels: heating oil, natural gas, and electricity. The Committee also asked EIA to examine the role of conservation in the choice of heating and cooling fuel. To accommodate a wide audience, EIA decided to respond to the Committee`s request in the context of a report on reducing home heating and cooling costs. Accordingly, this report discusses ways to weatherize the home, compares the features of the three major heating and cooling fuels, and comments on the types of heating and cooling systems on the market. The report also includes a worksheet and supporting tables that will help in the selection of a heating and/or cooling system.

  11. Optimal Ground Source Heat Pump System Design

    SciTech Connect

    Ozbek, Metin; Yavuzturk, Cy; Pinder, George

    2015-04-01

    Despite the facts that GSHPs first gained popularity as early as the 1940’s and they can achieve 30 to 60 percent in energy savings and carbon emission reductions relative to conventional HVAC systems, the use of geothermal energy in the U.S. has been less than 1 percent of the total energy consumption. The key barriers preventing this technically-mature technology from reaching its full commercial potential have been its high installation cost and limited consumer knowledge and trust in GSHP systems to deliver the technology in a cost-effective manner in the market place. Led by ENVIRON, with support from University Hartford and University of Vermont, the team developed and tested a software-based a decision making tool (‘OptGSHP’) for the least-cost design of ground-source heat pump (‘GSHP’) systems. OptGSHP combines state of the art optimization algorithms with GSHP-specific HVAC and groundwater flow and heat transport simulation. The particular strength of OptGSHP is in integrating heat transport due to groundwater flow into the design, which most of the GSHP designs do not get credit for and therefore are overdesigned.

  12. Low cost process heat recovery. Interim report

    SciTech Connect

    Theisen, P.; McCray, J.

    1980-01-01

    The objectives of this project are to analyze waste heat recovery potential, economic analysis, heat exchanger and system design, and computer analysis programs. The heating demand and heat recovery potential at a Madison neighborhood bakery was conducted. The building has steam heat and natural gas is used in the hot water heater, the cooking stoves, and in the baking oven. Heat recovery potential was analyzed based upon fuel consumption in the baking oven, flue gas temperature, mass flow rate, and hours of oven operation. The feasibility of waste heat recovery systems is analyzed using life cycle cost and life cycle savings. For a first approximation, hand calculations were performed for air-to-air flat plate, fin-plate, and liquid-to-air tube type heat exchangers using the temperature and mass flow data from a pizza restaurant in Madison. Then a heat exchanger analysis program was written in interactive BASIC. The analysis indicates that heat recovery using the flat-plate and fin-plate exchanger designs is technically feasible and yields high effectiveness. (MCW)

  13. Selection and costing of heat exchangers

    NASA Astrophysics Data System (ADS)

    1992-12-01

    ESDU 92013 gives guidance on the selection of heat exchanger types for a given duty against various criteria; they include the general characteristics, together with such detailed aspects as the ranges of pressure and temperature appropriate, compatibility with the fluids involved, space and weight requirements, and cleaning accessibility and maintenance. That allows an initial choice to be made from 18 principal types of exchangers. The various types are all illustrated. A final choice can then be made between the feasible types on the basis of costs. Detailed costing data provided by manufacturers are tabulated as a function of heat load, operating pressure and the types of cold- and hot-side fluids for the following types of exchangers: shell-and-tube, double-pipe, printed-circuit, plate-fin, air-cooled and welded plate. Costing data are also tabulated as a function of heat load and the types of cold- and hot-side fluids for gasketed-plate exchangers. Seven worked examples of selection based on technical suitability and using the tabulated cost data illustrate fully the use of the information.

  14. Low-Cost Constant Temperature Heating Block

    NASA Astrophysics Data System (ADS)

    Shevlin, Charles G.; Coppersmith, Ward; Fish, Christopher; Vlock, Stanley; Vellema, William

    1997-08-01

    A simple constant temperature heat block was constructed from readily available materials. The configuration of the heating block can be constructed to meet the needs of any laboratory. Some highlights of this temperature controller include the elimination of dangerous flames and cumbersome water baths, maintenance of temperature over a wide range within 1 °C and compact electronics. In addition, the IC power supply circuit is self-contained thus eliminating the need for bulky transformers and additional power related circuitry. Secondary school and undergraduate laboratories can build many units for the cost of a commercially comparable one while simultaneously putting to practice several electronic principles taught in most instrumental analysis courses.

  15. Low-Cost Gas Heat Pump for Building Space Heating

    SciTech Connect

    Garrabrant, Michael; Keinath, Christopher

    2016-10-11

    Gas-fired residential space heating in the U.S is predominantly supplied by furnaces and boilers. These technologies have been approaching their thermodynamic limit over the past 30 years and improvements for high efficiency units have approached a point of diminishing return. Electric heat pumps are growing in popularity but their heating performance at low ambient temperatures is poor. The development of a low-cost gas absorption heat pump would offer a significant improvement to current furnaces and boilers, and in heating dominated climate zones when compared to electric heat pumps. Gas absorption heat pumps (GAHP) exceed the traditional limit of thermal efficiency encountered by typical furnaces and boilers, and maintain high levels of performance at low ambient temperatures. The project team designed and demonstrated two low-cost packaged prototype GAHP space heating systems during the course of this investigation. Led by Stone Mountain Technologies Inc. (SMTI), with support from A.O. Smith, and the Gas Technology Institute (GTI), the cross-functional team completed research and development tasks including cycle modeling, 8× scaling of a compact solution pump, combustion system development, breadboard evaluation, fabrication of two packaged prototype units, third party testing of the first prototype, and the evaluation of cost and energy savings compared to high and minimum efficiency gas options. Over the course of the project and with the fabrication of two Alpha prototypes it was shown that this technology met or exceeded most of the stated project targets. At ambient temperatures of 47, 35, 17 and -13°F the prototypes achieved gas based coefficients of performance of 1.50, 1.44, 1.37, and 1.17, respectively. Both units operated with parasitic loads well below the 750 watt target with the second Alpha prototype operating 75-100 watts below the first Alpha prototype. Modulation of the units at 4:1 was achieved with the project goal of 2:1 modulation

  16. Gasification Plant Cost and Performance Optimization

    SciTech Connect

    Samuel Tam; Alan Nizamoff; Sheldon Kramer; Scott Olson; Francis Lau; Mike Roberts; David Stopek; Robert Zabransky; Jeffrey Hoffmann; Erik Shuster; Nelson Zhan

    2005-05-01

    As part of an ongoing effort of the U.S. Department of Energy (DOE) to investigate the feasibility of gasification on a broader level, Nexant, Inc. was contracted to perform a comprehensive study to provide a set of gasification alternatives for consideration by the DOE. Nexant completed the first two tasks (Tasks 1 and 2) of the ''Gasification Plant Cost and Performance Optimization Study'' for the DOE's National Energy Technology Laboratory (NETL) in 2003. These tasks evaluated the use of the E-GAS{trademark} gasification technology (now owned by ConocoPhillips) for the production of power either alone or with polygeneration of industrial grade steam, fuel gas, hydrocarbon liquids, or hydrogen. NETL expanded this effort in Task 3 to evaluate Gas Technology Institute's (GTI) fluidized bed U-GAS{reg_sign} gasifier. The Task 3 study had three main objectives. The first was to examine the application of the gasifier at an industrial application in upstate New York using a Southeastern Ohio coal. The second was to investigate the GTI gasifier in a stand-alone lignite-fueled IGCC power plant application, sited in North Dakota. The final goal was to train NETL personnel in the methods of process design and systems analysis. These objectives were divided into five subtasks. Subtasks 3.2 through 3.4 covered the technical analyses for the different design cases. Subtask 3.1 covered management activities, and Subtask 3.5 covered reporting. Conceptual designs were developed for several coal gasification facilities based on the fluidized bed U-GAS{reg_sign} gasifier. Subtask 3.2 developed two base case designs for industrial combined heat and power facilities using Southeastern Ohio coal that will be located at an upstate New York location. One base case design used an air-blown gasifier, and the other used an oxygen-blown gasifier in order to evaluate their relative economics. Subtask 3.3 developed an advanced design for an air-blown gasification combined heat and power

  17. Development of optimized, graded-permeability axial groove heat pipes

    NASA Technical Reports Server (NTRS)

    Kapolnek, Michael R.; Holmes, H. Rolland

    1988-01-01

    Heat pipe performance can usually be improved by uniformly varying or grading wick permeability from end to end. A unique and cost effective method for grading the permeability of an axial groove heat pipe is described - selective chemical etching of the pipe casing. This method was developed and demonstrated on a proof-of-concept test article. The process improved the test article's performance by 50 percent. Further improvement is possible through the use of optimally etched grooves.

  18. Messaging with Cost-Optimized Interstellar Beacons

    NASA Technical Reports Server (NTRS)

    Benford, James; Benford, Gregory; Benford, Dominic

    2010-01-01

    On Earth, how would we build galactic-scale beacons to attract the attention of extraterrestrials, as some have suggested we should do? From the point of view of expense to a builder on Earth, experience shows an optimum trade-off. This emerges by minimizing the cost of producing a desired power density at long range, which determines the maximum range of detectability of a transmitted signal. We derive general relations for cost-optimal aperture and power. For linear dependence of capital cost on transmitter power and antenna area, minimum capital cost occurs when the cost is equally divided between antenna gain and radiated power. For nonlinear power-law dependence, a similar simple division occurs. This is validated in cost data for many systems; industry uses this cost optimum as a rule of thumb. Costs of pulsed cost-efficient transmitters are estimated from these relations by using current cost parameters ($/W, $/sq m) as a basis. We show the scaling and give examples of such beacons. Galactic-scale beacons can be built for a few billion dollars with our present technology. Such beacons have narrow "searchlight" beams and short "dwell times" when the beacon would be seen by an alien observer in their sky. More-powerful beacons are more efficient and have economies of scale: cost scales only linearly with range R, not as R(exp 2), so number of stars radiated to increases as the square of cost. On a cost basis, they will likely transmit at higher microwave frequencies, -10 GHz. The natural corridor to broadcast is along the galactic radius or along the local spiral galactic arm we are in. A companion paper asks "If someone like us were to produce a beacon, how should we look for it?"

  19. Messaging with Cost-Optimized Interstellar Beacons

    NASA Astrophysics Data System (ADS)

    Benford, James; Benford, Gregory; Benford, Dominic

    2010-06-01

    On Earth, how would we build galactic-scale beacons to attract the attention of extraterrestrials, as some have suggested we should do? From the point of view of expense to a builder on Earth, experience shows an optimum trade-off. This emerges by minimizing the cost of producing a desired power density at long range, which determines the maximum range of detectability of a transmitted signal. We derive general relations for cost-optimal aperture and power. For linear dependence of capital cost on transmitter power and antenna area, minimum capital cost occurs when the cost is equally divided between antenna gain and radiated power. For nonlinear power-law dependence, a similar simple division occurs. This is validated in cost data for many systems; industry uses this cost optimum as a rule of thumb. Costs of pulsed cost-efficient transmitters are estimated from these relations by using current cost parameters (/W, /m2) as a basis. We show the scaling and give examples of such beacons. Galactic-scale beacons can be built for a few billion dollars with our present technology. Such beacons have narrow "searchlight" beams and short "dwell times" when the beacon would be seen by an alien observer in their sky. More-powerful beacons are more efficient and have economies of scale: cost scales only linearly with range R, not as R2, so number of stars radiated to iincreases as the square of cost. On a cost basis, they will likely transmit at higher microwave frequencies, ˜10 GHz. The natural corridor to broadcast is along the galactic radius or along the local spiral galactic arm we are in. A companion paper asks "If someone like us were to produce a beacon, how should we look for it?"

  20. A Program for Optimizing SRF Linac Costs

    SciTech Connect

    Powers, Thomas J.

    2013-04-01

    Every well-designed machine goes through the process of cost optimization several times during its design, production and operation. The initial optimizations are done during the early proposal stage of the project when none of the systems have been engineered. When a superconducting radio frequency (SRF) linac is implemented as part of the design, it is often a difficult decision as to the frequency and gradient that will be used. Frequently, such choices are made based on existing designs, which invariably necessitate moderate to substantial modifications so that they can be used in the new accelerator. Thus the fallacy of using existing designs is that they will frequently provide a higher cost machine or a machine with sub-optimal beam physics parameters. This paper describes preliminary results of a new software tool that allows one to vary parameters and understand the effects on the optimized costs of construction plus 10 year operations of an SRF linac, the associated cryogenic facility, and controls, where operations includes the cost of the electrical utilities but not the labor or other costs. It derives from collaborative work done with staff from Accelerator Science and Technology Centre, Daresbury, UK [1] several years ago while they were in the process of developing a conceptual design for the New Light Source project. The initial goal was to convert a spread sheet format to a graphical interface to allow the ability to sweep different parameter sets. The tools also allow one to compare the cost of the different facets of the machine design and operations so as to better understand the tradeoffs.

  1. Optimization of Transient Heat Exchanger Performance for Improved Energy Efficiency

    NASA Astrophysics Data System (ADS)

    Bran Anleu, Gabriela; Kavehpour, Pirouz; Lavine, Adrienne; Wirz, Richard

    2014-11-01

    Heat exchangers are used in a multitude of applications within systems for energy generation, energy conversion, or energy storage. Many of these systems (e.g. solar power plants) function under transient conditions, but the design of the heat exchangers is typically optimized assuming steady state conditions. There is a potential for significant energy savings if the transient behavior of the heat exchanger is taken into account in designing the heat exchanger by optimizing its operating conditions in relation to the transient behavior of the overall system. The physics of the transient behavior of a heat exchanger needs to be understood to provide design parameters for transient heat exchangers to deliver energy savings. A numerical model was used to determine the optimized mass flow rates thermal properties for a thermal energy storage system. The transient behavior is strongly linked to the dimensionless parameters relating fluid properties, the mass flow rates, and the temperature of the fluids at the inlet of each stream. Smart metals, or advanced heat exchanger surface geometries and methods of construction will be used to meet the three goals mentioned before: 1) energy and cost reduction, 2) size reduction, and 3) optimal performance for all modes of operation.

  2. Evaluation of fluid bed heat exchanger optimization parameters. Final report

    SciTech Connect

    Not Available

    1980-03-01

    Uncertainty in the relationship of specific bed material properties to gas-side heat transfer in fluidized beds has inhibited the search for optimum bed materials and has led to over-conservative assumptions in the design of fluid bed heat exchangers. An experimental program was carried out to isolate the effects of particle density, thermal conductivity, and heat capacitance upon fluid bed heat transfer. A total of 31 tests were run with 18 different bed material loads on 12 material types; particle size variations were tested on several material types. The conceptual design of a fluidized bed evaporator unit was completed for a diesel exhaust heat recovery system. The evaporator heat transfer surface area was substantially reduced while the physical dimensions of the unit increased. Despite the overall increase in unit size, the overall cost was reduced. A study of relative economics associated with bed material selection was conducted. For the fluidized bed evaporator, it was found that zircon sand was the best choice among materials tested in this program, and that the selection of bed material substantially influences the overall system costs. The optimized fluid bed heat exchanger has an estimated cost 19% below a fin augmented tubular heat exchanger; 31% below a commercial design fluid bed heat exchanger; and 50% below a conventional plain tube heat exchanger. The comparisons being made for a 9.6 x 10/sup 6/ Btu/h waste heat boiler. The fluidized bed approach potentially has other advantages such as resistance to fouling. It is recommended that a study be conducted to develop a systematic selection of bed materials for fluidized bed heat exchanger applications, based upon findings of the study reported herein.

  3. Cost Scaling of a Real-World Exhaust Waste Heat Recovery Thermoelectric Generator: A Deeper Dive

    NASA Astrophysics Data System (ADS)

    Hendricks, Terry J.; Yee, Shannon; LeBlanc, Saniya

    2016-03-01

    Cost is equally important to power density or efficiency for the adoption of waste heat recovery thermoelectric generators (TEG) in many transportation and industrial energy recovery applications. In many cases, the system design that minimizes cost (e.g., the /W value) can be very different than the design that maximizes the system's efficiency or power density, and it is important to understand the relationship between those designs to optimize TEG performance-cost compromises. Expanding on recent cost analysis work and using more detailed system modeling, an enhanced cost scaling analysis of a waste heat recovery TEG with more detailed, coupled treatment of the heat exchangers has been performed. In this analysis, the effect of the heat lost to the environment and updated relationships between the hot-side and cold-side conductances that maximize power output are considered. This coupled thermal and thermoelectric (TE) treatment of the exhaust waste heat recovery TEG yields modified cost scaling and design optimization equations, which are now strongly dependent on the heat leakage fraction, exhaust mass flow rate, and heat exchanger effectiveness. This work shows that heat exchanger costs most often dominate the overall TE system costs, that it is extremely difficult to escape this regime, and in order to achieve TE system costs of 1/W it is necessary to achieve heat exchanger costs of 1/(W/K). Minimum TE system costs per watt generally coincide with maximum power points, but preferred TE design regimes are identified where there is little cost penalty for moving into regions of higher efficiency and slightly lower power outputs. These regimes are closely tied to previously identified low cost design regimes. This work shows that the optimum fill factor F opt minimizing system costs decreases as heat losses increase, and increases as exhaust mass flow rate and heat exchanger effectiveness increase. These findings have profound implications on the design and

  4. Optimal joule heating of the subsurface

    DOEpatents

    Berryman, James G.; Daily, William D.

    1994-01-01

    A method for simultaneously heating the subsurface and imaging the effects of the heating. This method combines the use of tomographic imaging (electrical resistance tomography or ERT) to image electrical resistivity distribution underground, with joule heating by electrical currents injected in the ground. A potential distribution is established on a series of buried electrodes resulting in energy deposition underground which is a function of the resistivity and injection current density. Measurement of the voltages and currents also permits a tomographic reconstruction of the resistivity distribution. Using this tomographic information, the current injection pattern on the driving electrodes can be adjusted to change the current density distribution and thus optimize the heating. As the heating changes conditions, the applied current pattern can be repeatedly adjusted (based on updated resistivity tomographs) to affect real time control of the heating.

  5. Optimal joule heating of the subsurface

    DOEpatents

    Berryman, J.G.; Daily, W.D.

    1994-07-05

    A method for simultaneously heating the subsurface and imaging the effects of the heating is disclosed. This method combines the use of tomographic imaging (electrical resistance tomography or ERT) to image electrical resistivity distribution underground, with joule heating by electrical currents injected in the ground. A potential distribution is established on a series of buried electrodes resulting in energy deposition underground which is a function of the resistivity and injection current density. Measurement of the voltages and currents also permits a tomographic reconstruction of the resistivity distribution. Using this tomographic information, the current injection pattern on the driving electrodes can be adjusted to change the current density distribution and thus optimize the heating. As the heating changes conditions, the applied current pattern can be repeatedly adjusted (based on updated resistivity tomographs) to affect real time control of the heating.

  6. Cost optimization of spacecraft test levels

    NASA Technical Reports Server (NTRS)

    Young, J. P.

    1974-01-01

    Common to all nondestructive type testing of hardware that provides the necessary confidence in the design is the question regarding the proper magnitude of the test level. The objective of this investigation was to study the possibility of establishing cost optimized test levels of a rather general nature. This investigation was based on studying the influence of test level on a cost of error cost model that reflects the adverse effects of 'undertesting' and 'overtesting'. For the assumed conditions of normal distribution for the random variables and a protoflight spacecraft case, the results indicated that the limits for an optimum test factor can range between slightly less than 1.0 to slightly more than 1.5.

  7. Optimal Management of Geothermal Heat Extraction

    NASA Astrophysics Data System (ADS)

    Patel, I. H.; Bielicki, J. M.; Buscheck, T. A.

    2015-12-01

    Geothermal energy technologies use the constant heat flux from the subsurface in order to produce heat or electricity for societal use. As such, a geothermal energy system is not inherently variable, like systems based on wind and solar resources, and an operator can conceivably control the rate at which heat is extracted and used directly, or converted into a commodity that is used. Although geothermal heat is a renewable resource, this heat can be depleted over time if the rate of heat extraction exceeds the natural rate of renewal (Rybach, 2003). For heat extraction used for commodities that are sold on the market, sustainability entails balancing the rate at which the reservoir renews with the rate at which heat is extracted and converted into profit, on a net present value basis. We present a model that couples natural resource economic approaches for managing renewable resources with simulations of geothermal reservoir performance in order to develop an optimal heat mining strategy that balances economic gain with the performance and renewability of the reservoir. Similar optimal control approaches have been extensively studied for renewable natural resource management of fisheries and forests (Bonfil, 2005; Gordon, 1954; Weitzman, 2003). Those models determine an optimal path of extraction of fish or timber, by balancing the regeneration of stocks of fish or timber that are not harvested with the profit from the sale of the fish or timber that is harvested. Our model balances the regeneration of reservoir temperature with the net proceeds from extracting heat and converting it to electricity that is sold to consumers. We used the Non-isothermal Unconfined-confined Flow and Transport (NUFT) model (Hao, Sun, & Nitao, 2011) to simulate the performance of a sedimentary geothermal reservoir under a variety of geologic and operational situations. The results of NUFT are incorporated into the natural resource economics model to determine production strategies that

  8. Cost analysis of new and retrofit hot-air type solar assisted heating systems

    NASA Technical Reports Server (NTRS)

    Stewart, R. D.; Hawkins, B. J.

    1978-01-01

    A detailed cost analysis/cost improvement study was performed on two Department of Energy/National Aeronautics and Space Administration operational test sites to determine actual costs and potential cost improvements of new and retrofit hot air type, solar assisted heating and hot water systems for single family sized structures. This analysis concentrated on the first cost of a system which included procurement, installation, and integration of a solar assisted heating and hot water system on a new or retrofit basis; it also provided several cost projections which can be used as inputs to payback analyses, depending upon the degree of optimism or future improvements assumed. Cost definitions were developed for five categories of cost, and preliminary estimates were developed for each. The costing methodology, approach, and results together with several candidate low cost designs are described.

  9. Optimization of Borehole Heat Exchanger Arrays

    NASA Astrophysics Data System (ADS)

    Schulte, Daniel; Rühaak, Wolfram; Welsch, Bastian; Oladyshkin, Sergey; Sass, Ingo

    2016-04-01

    Arrays of borehole heat exchangers are an increasingly popular source for renewable energy. Furthermore, they can serve as borehole thermal energy storages for seasonally fluctuating heat sources like solar thermal energy or district heating grids. However, the uncertainty of geological parameters and the nonlinear behavior of the complex system make it difficult to simulate and predict the required design of borehole heat exchanger arrays. As a result, the arrays easily turn out to be over or undersized, which compromises the economic feasibility of these systems. Here, we present a novel optimization strategy for the design of borehole thermal energy storages. The arbitrary polynomial chaos expansion method is used to build a proxy model from a set of numerical training simulations, which allows for the consideration of parameter uncertainties. Thus, the resulting proxy model bypasses the problem of excessive computation time for the numerous function calls required for a mathematical optimization. Additionally, we iteratively refine the proxy model during the optimization procedure using additional numerical simulation runs. With the presented solution, many aspects of borehole heat exchanger arrays can be optimized under geological uncertainty.

  10. Solar Water Heating with Low-Cost Plastic Systems (Brochure)

    SciTech Connect

    Not Available

    2012-01-01

    Newly developed solar water heating technology can help Federal agencies cost effectively meet the EISA requirements for solar water heating in new construction and major renovations. This document provides design considerations, application, economics, and maintenance information and resources.

  11. GASIFICATION PLANT COST AND PERFORMANCE OPTIMIZATION

    SciTech Connect

    Samuel S. Tam

    2002-05-01

    The goal of this series of design and estimating efforts was to start from the as-built design and actual operating data from the DOE sponsored Wabash River Coal Gasification Repowering Project and to develop optimized designs for several coal and petroleum coke IGCC power and coproduction projects. First, the team developed a design for a grass-roots plant equivalent to the Wabash River Coal Gasification Repowering Project to provide a starting point and a detailed mid-year 2000 cost estimate based on the actual as-built plant design and subsequent modifications (Subtask 1.1). This unoptimized plant has a thermal efficiency of 38.3% (HHV) and a mid-year 2000 EPC cost of 1,681 $/kW. This design was enlarged and modified to become a Petroleum Coke IGCC Coproduction Plant (Subtask 1.2) that produces hydrogen, industrial grade steam, and fuel gas for an adjacent Gulf Coast petroleum refinery in addition to export power. A structured Value Improving Practices (VIP) approach was applied to reduce costs and improve performance. The base case (Subtask 1.3) Optimized Petroleum Coke IGCC Coproduction Plant increased the power output by 16% and reduced the plant cost by 23%. The study looked at several options for gasifier sparing to enhance availability. Subtask 1.9 produced a detailed report on this availability analyses study. The Subtask 1.3 Next Plant, which retains the preferred spare gasification train approach, only reduced the cost by about 21%, but it has the highest availability (94.6%) and produces power at 30 $/MW-hr (at a 12% ROI). Thus, such a coke-fueled IGCC coproduction plant could fill a near term niche market. In all cases, the emissions performance of these plants is superior to the Wabash River project. Subtasks 1.5A and B developed designs for single-train coal and coke-fueled power plants. This side-by-side comparison of these plants, which contain the Subtask 1.3 VIP enhancements, showed their similarity both in design and cost (1,318 $/kW for the

  12. Operational cost minimization of heat pump for milk pasteurization in dairy.

    PubMed

    Söylemez, Mehmet Sait

    2005-11-01

    A thermo economic optimization analysis is presented yielding simple algebraic formula for estimating the optimum operating conditions of interconnected heat pump assisted milk pasteurizing systems. The overall operational cost method including the cost of auxiliary heater is used in the present study, together with the thermal analyses of all system components, for thermo economic analysis of the system.

  13. Low cost fabrication of ablative heat shields

    NASA Technical Reports Server (NTRS)

    Cecka, A. M.; Schofield, W. C.

    1972-01-01

    A material and process study was performed using subscale panels in an attempt to reduce the cost of fabricating ablative heat shield panels. Although no improvements were made in the material formulation, a significant improvement was obtained in the processing methods compared to those employed in the previous work. The principal feature of the new method is the press filling and curing of the ablation material in a single step with the bonding and curing of the face sheet. This method was chosen to replace the hand troweling and autoclave curing procedure used previously. Double-curvature panels of the same size as the flat panels were fabricated to investigate fabrication problems. It was determined that the same materials and processes used for flat panels can be used to produce the curved panels. A design with severe curvatures consisting of radii of 24 x 48 inches was employed for evaluation. Ten low-density and ten high-density panels were fabricated. With the exception of difficulties related to short run non-optimum tooling, excellent panel filling and density uniformity were obtained.

  14. Cost Optimization and Technology Enablement COTSAT-1

    NASA Technical Reports Server (NTRS)

    Spremo, Stevan; Lindsay, Michael C.; Klupar, Peter Damian; Swank, Aaron J.

    2010-01-01

    Cost Optimized Test of Spacecraft Avionics and Technologies (COTSAT-1) is an ongoing spacecraft research and development project at NASA Ames Research Center (ARC). The space industry was a hot bed of innovation and development at its birth. Many new technologies were developed for and first demonstrated in space. In the recent past this trend has reversed with most of the new technology funding and research being driven by the private industry. Most of the recent advances in spaceflight hardware have come from the cell phone industry with a lag of about 10 to 15 years from lab demonstration to in space usage. NASA has started a project designed to address this problem. The prototype spacecraft known as Cost Optimized Test of Spacecraft Avionics and Technologies (COTSAT-1) and CheapSat work to reduce these issues. This paper highlights the approach taken by NASA Ames Research center to achieve significant subsystem cost reductions. The COSTAT-1 research system design incorporates use of COTS (Commercial Off The Shelf), MOTS (Modified Off The Shelf), and GOTS (Government Off The Shelf) hardware for a remote sensing spacecraft. The COTSAT-1 team demonstrated building a fully functional spacecraft for $500K parts and $2.0M labor. The COTSAT-1 system, including a selected science payload, is described within this paper. Many of the advancements identified in the process of cost reduction can be attributed to the use of a one-atmosphere pressurized structure to house the spacecraft components. By using COTS hardware, the spacecraft program can utilize investments already made by commercial vendors. This ambitious project development philosophy/cycle has yielded the COTSAT-1 flight hardware. This paper highlights the advancements of the COTSAT-1 spacecraft leading to the delivery of the current flight hardware that is now located at NASA Ames Research Center. This paper also addresses the plans for COTSAT-2.

  15. GASIFICATION PLANT COST AND PERFORMANCE OPTIMIZATION

    SciTech Connect

    Sheldon Kramer

    2003-09-01

    This project developed optimized designs and cost estimates for several coal and petroleum coke IGCC coproduction projects that produced hydrogen, industrial grade steam, and hydrocarbon liquid fuel precursors in addition to power. The as-built design and actual operating data from the DOE sponsored Wabash River Coal Gasification Repowering Project was the starting point for this study that was performed by Bechtel, Global Energy and Nexant under Department of Energy contract DE-AC26-99FT40342. First, the team developed a design for a grass-roots plant equivalent to the Wabash River Coal Gasification Repowering Project to provide a starting point and a detailed mid-year 2000 cost estimate based on the actual as-built plant design and subsequent modifications (Subtask 1.1). This non-optimized plant has a thermal efficiency to power of 38.3% (HHV) and a mid-year 2000 EPC cost of 1,681 $/kW.1 This design was enlarged and modified to become a Petroleum Coke IGCC Coproduction Plant (Subtask 1.2) that produces hydrogen, industrial grade steam, and fuel gas for an adjacent Gulf Coast petroleum refinery in addition to export power. A structured Value Improving Practices (VIP) approach was applied to reduce costs and improve performance. The base case (Subtask 1.3) Optimized Petroleum Coke IGCC Coproduction Plant increased the power output by 16% and reduced the plant cost by 23%. The study looked at several options for gasifier sparing to enhance availability. Subtask 1.9 produced a detailed report on this availability analyses study. The Subtask 1.3 Next Plant, which retains the preferred spare gasification train approach, only reduced the cost by about 21%, but it has the highest availability (94.6%) and produces power at 30 $/MW-hr (at a 12% ROI). Thus, such a coke-fueled IGCC coproduction plant could fill a near term niche market. In all cases, the emissions performance of these plants is superior to the Wabash River project. Subtasks 1.5A and B developed designs for

  16. Optimal Operation System of the Integrated District Heating System with Multiple Regional Branches

    NASA Astrophysics Data System (ADS)

    Kim, Ui Sik; Park, Tae Chang; Kim, Lae-Hyun; Yeo, Yeong Koo

    This paper presents an optimal production and distribution management for structural and operational optimization of the integrated district heating system (DHS) with multiple regional branches. A DHS consists of energy suppliers and consumers, district heating pipelines network and heat storage facilities in the covered region. In the optimal management system, production of heat and electric power, regional heat demand, electric power bidding and sales, transport and storage of heat at each regional DHS are taken into account. The optimal management system is formulated as a mixed integer linear programming (MILP) where the objectives is to minimize the overall cost of the integrated DHS while satisfying the operation constraints of heat units and networks as well as fulfilling heating demands from consumers. Piecewise linear formulation of the production cost function and stairwise formulation of the start-up cost function are used to compute nonlinear cost function approximately. Evaluation of the total overall cost is based on weekly operations at each district heat branches. Numerical simulations show the increase of energy efficiency due to the introduction of the present optimal management system.

  17. Optimal control studies of solar heating systems

    SciTech Connect

    Winn, C B

    1980-01-01

    In the past few years fuel prices have seen steady increases. Also, the supply of fuel has been on the decline. Because of these two problems there has been an increase in the number of solar heated buildings. Since conventional fuel prices are increasing and as a solar heating system represents a high capital cost it is desirable to obtain the maximum performance from a solar heating system. The control scheme that is used in a solar heated building has an effect on the performance of the solar system. The best control scheme possible would, of course, be desired. This report deals with the control problems of a solar heated building. The first of these problems is to control the inside temperature of the building and to minimize the fuel consumption. This problem applies to both solar and conventionally heated buildings. The second problem considered is to control the collector fluid flow to maximize the difference between the useful energy collected and the energy required to pump the fluid. The third problem is to control the enclosure temperature of a building which has two sources of heat, one solar and the other conventional.

  18. Adaptive control based on retrospective cost optimization

    NASA Astrophysics Data System (ADS)

    Santillo, Mario A.

    This dissertation studies adaptive control of multi-input, multi-output, linear, time-invariant, discrete-time systems that are possibly unstable and nonminimum phase. We consider both gradient-based adaptive control as well as retrospective-cost-based adaptive control. Retrospective cost optimization is a measure of performance at the current time based on a past window of data and without assumptions about the command or disturbance signals. In particular, retrospective cost optimization acts as an inner loop to the adaptive control algorithm by modifying the performance variables based on the difference between the actual past control inputs and the recomputed past control inputs based on the current control law. We develop adaptive control algorithms that are effective for systems that are nonminimum phase. We consider discrete-time adaptive control since these control laws can be implemented directly in embedded code without requiring an intermediate discretization step. Furthermore, the adaptive controllers in this dissertation are developed under minimal modeling assumptions. In particular, the adaptive controllers require knowledge of the sign of the high-frequency gain and a sufficient number of Markov parameters to approximate the nonminimum-phase zeros (if any). No additional modeling information is necessary. The adaptive controllers presented in this dissertation are developed for full-state-feedback stabilization, static-output-feedback stabilization, as well as dynamic compensation for stabilization, command following, disturbance rejection, and model reference adaptive control. Lyapunov-based stability and convergence proofs are provided for special cases. We present numerical examples to illustrate the algorithms' effectiveness in handling systems that are unstable and/or nonminimum phase and to provide insight into the modeling information required for controller implementation.

  19. Costs and benefits of realism and optimism

    PubMed Central

    Bortolotti, Lisa; Antrobus, Magdalena

    2015-01-01

    Purpose of review What is the relationship between rationality and mental health? By considering the psychological literature on depressive realism and unrealistic optimism, it was hypothesized that, in the context of judgments about the self, accurate cognitions are psychologically maladaptive and inaccurate cognitions are psychologically adaptive. Recent studies recommend being cautious in drawing any general conclusion about the style of thinking and mental health. Recent findings Recent investigations suggest that people with depressive symptoms are more accurate than controls in tasks involving time perception and estimates of personal circumstances, but not in other tasks. Unrealistic optimism remains a robust phenomenon across a variety of tasks and domains, and researchers are starting to explore its neural bases. However, the challenge is to determine to what extent and in what way unrealistic optimism is beneficial. Summary We should revisit the hypothesis that optimistic cognitions are psychologically adaptive, whereas realistic thinking is not. Realistic beliefs and expectations can be conducive to wellbeing and good functioning, and wildly optimistic cognitions have considerable psychological costs. PMID:25594418

  20. Numerical simulation and optimization of enhanced heat transfer for high power LED light

    NASA Astrophysics Data System (ADS)

    Ge, Pu; Peng, Xu; Houchao, Miao; Li, Zhang

    2013-07-01

    A mathematical model of high power LED lights heat transfer was established, in which heat transfer structure of heat pipe was simplified based on the equivalent thermal resistance network model, and numerically solved by using the CFD software, the steady state temperature distributions were obtained. The simulation results indicate that ambient air temperature, the number of heat pipe, the thickness of bond coating, and the size of radiator play important roles for LED chip temperature, however, the influence of copper sink thickness is negligible. The heat transfer structure was optimized based on these results, and the optimized structure can achieve a better balance between cost reducing and heat transfer enhancement.

  1. Maximum power, ecological function and efficiency of an irreversible Carnot cycle: a cost and effectiveness optimization

    NASA Astrophysics Data System (ADS)

    Aragón-González, G.; Canales-Palma, A.; León-Galicia, A.; Morales-Gómez, J. R.

    2008-12-01

    In this work we include, for the Carnot cycle, irreversibilities of linear finite rate of heat transferences between the heat engine and its reservoirs, heat leak between the reservoirs and internal dissipations of the working fluid. A first optimization of the power output, the efficiency and ecological function of an irreversible Carnot cycle, with respect to: internal temperature ratio, time ratio for the heat exchange and the allocation ratio of the heat exchangers; is performed. For the second and third optimizations, the optimum values for the time ratio and internal temperature ratio are substituted into the equation of power and, then, the optimizations with respect to the cost and effectiveness ratio of the heat exchangers are performed. Finally, a criterion of partial optimization for the class of irreversible Carnot engines is herein presented.

  2. Cost Overrun Optimism: Fact or Fiction

    DTIC Science & Technology

    2016-02-29

    COST VARIANCE, TERMED COST OVERRUN COST NOW MONTHS EAC Overrun at Completion Current Overrun BAC ACWP BCWS...ALL 64 18 -3 109 36 -3 493 Equations 1, 2, and 3 define the current cost overrun, the projected cost overrun at completion, and final cost overrun. Of...completion cost . The others are simply the difference between the budget and actual cost of the work. Current overrun (CO) = Cumulative (Cum) BCWP -

  3. A low-computational-cost inverse heat transfer technique for convective heat transfer measurements in hypersonic flows

    NASA Astrophysics Data System (ADS)

    Avallone, F.; Greco, C. S.; Schrijer, F. F. J.; Cardone, G.

    2015-04-01

    The measurement of the convective wall heat flux in hypersonic flows may be particularly challenging in the presence of high-temperature gradients and when using high-thermal-conductivity materials. In this case, the solution of multidimensional problems is necessary, but it considerably increases the computational cost. In this paper, a low-computational-cost inverse data reduction technique is presented. It uses a recursive least-squares approach in combination with the trust-region-reflective algorithm as optimization procedure. The computational cost is reduced by performing the discrete Fourier transform on the discrete convective heat flux function and by identifying the most relevant coefficients as objects of the optimization algorithm. In the paper, the technique is validated by means of both synthetic data, built in order to reproduce physical conditions, and experimental data, carried out in the Hypersonic Test Facility Delft at Mach 7.5 on two wind tunnel models having different thermal properties.

  4. Thermoeconomic Optimization of a Combined Heating and Humidification Coil for HVAC Systems

    NASA Astrophysics Data System (ADS)

    Teodoros, Liliana; Andresen, Bjarne

    2016-07-01

    The total cost of ownership is calculated for a combined heating and humidification coil of an air-handling unit taking into account investment and operation costs simultaneously. This total cost represents the optimization function for which the minimum is sought. The parameters for the cost dependencies are the physical dimensions of the coil: length, width and height. The term "coil" is used generically since in this setup it generates heating as well as humidification in a single unit. The first part of the paper deals with the constructive optimization and finds the relationship between the dimensions for a minimum cost. The second part of the paper takes the results of the constructive optimization further and, based on the data derived in our previous papers, analyzes the minimum total cost for the humidification coil while balancing the amount of water used to humidify the air and modify its temperature.

  5. Cost optimization in low volume VLSI circuits

    NASA Technical Reports Server (NTRS)

    Cook, K. B., Jr.; Kerns, D. V., Jr.

    1982-01-01

    The relationship of integrated circuit (IC) cost to electronic system cost is developed using models for integrated circuit cost which are based on design/fabrication approach. Emphasis is on understanding the relationship between cost and volume for custom circuits suitable for NASA applications. In this report, reliability is a major consideration in the models developed. Results are given for several typical IC designs using off the shelf, full custom, and semicustom IC's with single and double level metallization.

  6. Low Cost Polymer heat Exchangers for Condensing Boilers

    SciTech Connect

    Butcher, Thomas; Trojanowski, Rebecca; Wei, George; Worek, Michael

    2015-09-30

    Work in this project sought to develop a suitable design for a low cost, corrosion resistant heat exchanger as part of a high efficiency condensing boiler. Based upon the design parameters and cost analysis several geometries and material options were explored. The project also quantified and demonstrated the durability of the selected polymer/filler composite under expected operating conditions. The core material idea included a polymer matrix with fillers for thermal conductivity improvement. While the work focused on conventional heating oil, this concept could also be applicable to natural gas, low sulfur heating oil, and biodiesel- although these are considered to be less challenging environments. An extruded polymer composite heat exchanger was designed, built, and tested during this project, demonstrating technical feasibility of this corrosion-resistant material approach. In such flue gas-to-air heat exchangers, the controlling resistance to heat transfer is in the gas-side convective layer and not in the tube material. For this reason, the lower thermal conductivity polymer composite heat exchanger can achieve overall heat transfer performance comparable to a metal heat exchanger. However, with the polymer composite, the surface temperature on the gas side will be higher, leading to a lower water vapor condensation rate.

  7. Thermal-economic multi-objective optimization of shell and tube heat exchanger using particle swarm optimization (PSO)

    NASA Astrophysics Data System (ADS)

    Ghanei, A.; Assareh, E.; Biglari, M.; Ghanbarzadeh, A.; Noghrehabadi, A. R.

    2014-10-01

    Many studies are performed by researchers about shell and tube heat exchanger (STHE) but the multi-objective particle swarm optimization (PSO) technique has never been used in such studies. This paper presents application of thermal-economic multi-objective optimization of STHE using PSO. For optimal design of a STHE, it was first thermally modeled using e-number of transfer units method while Bell-Delaware procedure was applied to estimate its shell side heat transfer coefficient and pressure drop. Multi objective PSO (MOPSO) method was applied to obtain the maximum effectiveness (heat recovery) and the minimum total cost as two objective functions. The results of optimal designs were a set of multiple optimum solutions, called `Pareto optimal solutions'. In order to show the accuracy of the algorithm, a comparison is made with the non-dominated sorting genetic algorithm (NSGA-II) and MOPSO which are developed for the same problem.

  8. Optimizing conceptual aircraft designs for minimum life cycle cost

    NASA Technical Reports Server (NTRS)

    Johnson, Vicki S.

    1989-01-01

    A life cycle cost (LCC) module has been added to the FLight Optimization System (FLOPS), allowing the additional optimization variables of life cycle cost, direct operating cost, and acquisition cost. Extensive use of the methodology on short-, medium-, and medium-to-long range aircraft has demonstrated that the system works well. Results from the study show that optimization parameter has a definite effect on the aircraft, and that optimizing an aircraft for minimum LCC results in a different airplane than when optimizing for minimum take-off gross weight (TOGW), fuel burned, direct operation cost (DOC), or acquisition cost. Additionally, the economic assumptions can have a strong impact on the configurations optimized for minimum LCC or DOC. Also, results show that advanced technology can be worthwhile, even if it results in higher manufacturing and operating costs. Examining the number of engines a configuration should have demonstrated a real payoff of including life cycle cost in the conceptual design process: the minimum TOGW of fuel aircraft did not always have the lowest life cycle cost when considering the number of engines.

  9. Low-Cost Solar Water Heating Research and Development Roadmap

    SciTech Connect

    Hudon, K.; Merrigan, T.; Burch, J.; Maguire, J.

    2012-08-01

    The market environment for solar water heating technology has changed substantially with the successful introduction of heat pump water heaters (HPWHs). The addition of this energy-efficient technology to the market increases direct competition with solar water heaters (SWHs) for available energy savings. It is therefore essential to understand which segment of the market is best suited for HPWHs and focus the development of innovative, low-cost SWHs in the market segment where the largest opportunities exist. To evaluate cost and performance tradeoffs between high performance hot water heating systems, annual energy simulations were run using the program, TRNSYS, and analysis was performed to compare the energy savings associated with HPWH and SWH technologies to conventional methods of water heating.

  10. Optimization of life cycle management costs

    SciTech Connect

    Banerjee, A.K.

    1994-12-31

    As can be seen from the case studies, a LCM program needs to address and integrate, in the decision process, technical, political, licensing, remaining plant life, component replacement cycles, and financial issues. As part of the LCM evaluations, existing plant programs, ongoing replacement projects, short and long-term operation and maintenance issues, and life extension strategies must be considered. The development of the LCM evaluations and the cost benefit analysis identifies critical technical and life cycle cost parameters. These {open_quotes}discoveries{close_quotes} result from the detailed and effective use of a consistent, quantifiable, and well documented methodology. The systematic development and implementation of a plant-wide LCM program provides for an integrated and structured process that leads to the most practical and effective recommendations. Through the implementation of these recommendations and cost effective decisions, the overall power production costs can be controlled and ultimately lowered.

  11. Investigation of low-cost fabrication of ablative heat shields

    NASA Technical Reports Server (NTRS)

    Massions, V. P.; Mach, R. W.

    1973-01-01

    The fabrication, testing, and evaluation of materials and techniques employed in the fabrication of ablative heat shield panels are described. Results of this effort show projected reductions in labor man-hours for dielectric curing of panels when compared to panels molded in a steam-heated press. In addition, panels were fabricated with more than one density within the cross-section. These dual-density panels show significant weight and cost reduction potentials.

  12. Optimizing Data Centre Energy and Environmental Costs

    NASA Astrophysics Data System (ADS)

    Aikema, David Hendrik

    Data centres use an estimated 2% of US electrical power which accounts for much of their total cost of ownership. This consumption continues to grow, further straining power grids attempting to integrate more renewable energy. This dissertation focuses on assessing and reducing data centre environmental and financial costs. Emissions of projects undertaken to lower the data centre environmental footprints can be assessed and the emission reduction projects compared using an ISO-14064-2-compliant greenhouse gas reduction protocol outlined herein. I was closely involved with the development of the protocol. Full lifecycle analysis and verifying that projects exceed business-as-usual expectations are addressed, and a test project is described. Consuming power when it is low cost or when renewable energy is available can be used to reduce the financial and environmental costs of computing. Adaptation based on the power price showed 10--50% potential savings in typical cases, and local renewable energy use could be increased by 10--80%. Allowing a fraction of high-priority tasks to proceed unimpeded still allows significant savings. Power grid operators use mechanisms called ancillary services to address variation and system failures, paying organizations to alter power consumption on request. By bidding to offer these services, data centres may be able to lower their energy costs while reducing their environmental impact. If providing contingency reserves which require only infrequent action, savings of up to 12% were seen in simulations. Greater power cost savings are possible for those ceding more control to the power grid operator. Coordinating multiple data centres adds overhead, and altering at which data centre requests are processed based on changes in the financial or environmental costs of power is likely to increase this overhead. Tests of virtual machine migrations showed that in some cases there was no visible increase in power use while in others power use

  13. Use of Algorithm of Changes for Optimal Design of Heat Exchanger

    NASA Astrophysics Data System (ADS)

    Tam, S. C.; Tam, H. K.; Chio, C. H.; Tam, L. M.

    2010-05-01

    For economic reasons, the optimal design of heat exchanger is required. Design of heat exchanger is usually based on the iterative process. The design conditions, equipment geometries, the heat transfer and friction factor correlations are totally involved in the process. Using the traditional iterative method, many trials are needed for satisfying the compromise between the heat exchange performance and the cost consideration. The process is cumbersome and the optimal design is often depending on the design engineer's experience. Therefore, in the recent studies, many researchers, reviewed in [1], applied the genetic algorithm (GA) [2] for designing the heat exchanger. The results outperformed the traditional method. In this study, the alternative approach, algorithm of changes, is proposed for optimal design of shell-tube heat exchanger [3]. This new method, algorithm of changes based on I Ching (???), is developed originality by the author. In the algorithms, the hexagram operations in I Ching has been generalized to binary string case and the iterative procedure which imitates the I Ching inference is also defined. On the basis of [3], the shell inside diameter, tube outside diameter, and baffles spacing were treated as the design (or optimized) variables. The cost of the heat exchanger was arranged as the objective function. Through the case study, the results show that the algorithm of changes is comparable to the GA method. Both of method can find the optimal solution in a short time. However, without interchanging information between binary strings, the algorithm of changes has advantage on parallel computation over GA.

  14. Optimizing Measurement Designs with Budget Constraints: The Variable Cost Case.

    ERIC Educational Resources Information Center

    Marcoulides, George A.

    1997-01-01

    Presents a procedure for determining the optimal number of conditions to use in multifaceted measurement designs when resource constraints are imposed. The procedure is illustrated for the case in which the costs per condition vary within the same facet. (Author)

  15. Searching for Cost-Optimized Interstellar Beacons

    NASA Technical Reports Server (NTRS)

    Benford, Gregory; Benford, James; Benford, Dominic

    2010-01-01

    What would SETI beacon transmitters be like if built by civilizations that had a variety of motives but cared about cost? In a companion paper, we presented how, for fixed power density in the far field, a cost-optimum interstellar beacon system could be built. Here, we consider how we should search for a beacon if it were produced by a civilization similar to ours. High-power transmitters could be built for a wide variety of motives other than the need for two-way communication, this would include beacons built to be seen over thousands of light-years. Extraterrestrial beacon builders would likely have to contend with economic pressures just as their terrestrial counterparts do. Cost, spectral lines near 1GHz, and interstellar scintillation favor radiating frequencies substantially above the classic "water hole." Therefore, the transmission strategy for a distant, cost-conscious beacon would be a rapid scan of the galactic plane with the intent to cover the angular space. Such pulses would be infrequent events for the receiver. Such beacons built by distant, advanced, wealthy societies would have very different characteristics from what SETI researchers seek. Future searches should pay special attention to areas along the galactic disk where SETI searches have seen coherent signals that have not recurred on the limited listening time intervals we have used. We will need to wait for recurring events that may arrive in intermittent bursts. Several new SETI search strategies have emerged from these ideas. We propose a new test for beacons that is based on the Life Plane hypotheses.

  16. Searching for cost-optimized interstellar beacons.

    PubMed

    Benford, Gregory; Benford, James; Benford, Dominic

    2010-06-01

    What would SETI beacon transmitters be like if built by civilizations that had a variety of motives but cared about cost? In a companion paper, we presented how, for fixed power density in the far field, a cost-optimum interstellar beacon system could be built. Here, we consider how we should search for a beacon if it were produced by a civilization similar to ours. High-power transmitters could be built for a wide variety of motives other than the need for two-way communication; this would include beacons built to be seen over thousands of light-years. Extraterrestrial beacon builders would likely have to contend with economic pressures just as their terrestrial counterparts do. Cost, spectral lines near 1 GHz, and interstellar scintillation favor radiating frequencies substantially above the classic "water hole." Therefore, the transmission strategy for a distant, cost-conscious beacon would be a rapid scan of the galactic plane with the intent to cover the angular space. Such pulses would be infrequent events for the receiver. Such beacons built by distant, advanced, wealthy societies would have very different characteristics from what SETI researchers seek. Future searches should pay special attention to areas along the galactic disk where SETI searches have seen coherent signals that have not recurred on the limited listening time intervals we have used. We will need to wait for recurring events that may arrive in intermittent bursts. Several new SETI search strategies have emerged from these ideas. We propose a new test for beacons that is based on the Life Plane hypotheses.

  17. Searching for Cost-Optimized Interstellar Beacons

    NASA Astrophysics Data System (ADS)

    Benford, Gregory; Benford, James; Benford, Dominic

    2010-06-01

    What would SETI beacon transmitters be like if built by civilizations that had a variety of motives but cared about cost? In a companion paper, we presented how, for fixed power density in the far field, a cost-optimum interstellar beacon system could be built. Here, we consider how we should search for a beacon if it were produced by a civilization similar to ours. High-power transmitters could be built for a wide variety of motives other than the need for two-way communication; this would include beacons built to be seen over thousands of light-years. Extraterrestrial beacon builders would likely have to contend with economic pressures just as their terrestrial counterparts do. Cost, spectral lines near 1 GHz, and interstellar scintillation favor radiating frequencies substantially above the classic "water hole." Therefore, the transmission strategy for a distant, cost-conscious beacon would be a rapid scan of the galactic plane with the intent to cover the angular space. Such pulses would be infrequent events for the receiver. Such beacons built by distant, advanced, wealthy societies would have very different characteristics from what SETI researchers seek. Future searches should pay special attention to areas along the galactic disk where SETI searches have seen coherent signals that have not recurred on the limited listening time intervals we have used. We will need to wait for recurring events that may arriarrive in intermittent bursts. Several new SETI search strategies have emerged from these ideas. We propose a new test for beacons that is based on the Life Plane hypotheses.

  18. Optimal shielding design for minimum materials cost or mass

    SciTech Connect

    Woolley, Robert D.

    2015-12-02

    The mathematical underpinnings of cost optimal radiation shielding designs based on an extension of optimal control theory are presented, a heuristic algorithm to iteratively solve the resulting optimal design equations is suggested, and computational results for a simple test case are discussed. A typical radiation shielding design problem can have infinitely many solutions, all satisfying the problem's specified set of radiation attenuation requirements. Each such design has its own total materials cost. For a design to be optimal, no admissible change in its deployment of shielding materials can result in a lower cost. This applies in particular to very small changes, which can be restated using the calculus of variations as the Euler-Lagrange equations. Furthermore, the associated Hamiltonian function and application of Pontryagin's theorem lead to conditions for a shield to be optimal.

  19. Optimal shielding design for minimum materials cost or mass

    DOE PAGES

    Woolley, Robert D.

    2015-12-02

    The mathematical underpinnings of cost optimal radiation shielding designs based on an extension of optimal control theory are presented, a heuristic algorithm to iteratively solve the resulting optimal design equations is suggested, and computational results for a simple test case are discussed. A typical radiation shielding design problem can have infinitely many solutions, all satisfying the problem's specified set of radiation attenuation requirements. Each such design has its own total materials cost. For a design to be optimal, no admissible change in its deployment of shielding materials can result in a lower cost. This applies in particular to very smallmore » changes, which can be restated using the calculus of variations as the Euler-Lagrange equations. Furthermore, the associated Hamiltonian function and application of Pontryagin's theorem lead to conditions for a shield to be optimal.« less

  20. Optimization of Composition and Heat Treating of Die Steels for Extended Lifetime

    SciTech Connect

    David Schwam; John F. Wallace; Quanyou Zhou

    2002-01-30

    An ''average'' die casting die costs fifty thousand dollars. A die used in making die cast aluminum engine blocks can cost well over one million dollars. These costs provide a strong incentive for extension of die life. While vacuum quenched Premium Grade H13 dies have become the most widely used in the United States, tool makers and die casters are constantly searching for new steels and heat treating procedures to extend die life. This project was undertaken to investigate the effects of composition and heat treating on die life and optimize these parameters.

  1. Optimization principle of operating parameters of heat exchanger by using CFD simulation

    NASA Astrophysics Data System (ADS)

    Mičieta, Jozef; Jiří, Vondál; Jandačka, Jozef; Lenhard, Richard

    2016-03-01

    Design of effective heat transfer devices and minimizing costs are desired sections in industry and they are important for both engineers and users due to the wide-scale use of heat exchangers. Traditional approach to design is based on iterative process in which is gradually changed design parameters, until a satisfactory solution is achieved. The design process of the heat exchanger is very dependent on the experience of the engineer, thereby the use of computational software is a major advantage in view of time. Determination of operating parameters of the heat exchanger and the subsequent estimation of operating costs have a major impact on the expected profitability of the device. There are on the one hand the material and production costs, which are immediately reflected in the cost of device. But on the other hand, there are somewhat hidden costs in view of economic operation of the heat exchanger. The economic balance of operation significantly affects the technical solution and accompanies the design of the heat exchanger since its inception. Therefore, there is important not underestimate the choice of operating parameters. The article describes an optimization procedure for choice of cost-effective operational parameters for a simple double pipe heat exchanger by using CFD software and the subsequent proposal to modify its design for more economical operation.

  2. Optimal Shielding for Minimum Materials Cost of Mass

    SciTech Connect

    Woolley, Robert D.

    2014-08-01

    Material costs dominate some shielding design problems. This is certainly the case for manned nuclear power space applications for which shielding is essential and the cost of launching by rocket from earth is high. In such situations or in those where shielding volume or mass is constrained, it is important to optimize the design. Although trial and error synthesis methods may succeed a more systematic approach is warranted. Design automation may also potentially reduce engineering costs.

  3. Application of trajectory optimization principles to minimize aircraft operating costs

    NASA Technical Reports Server (NTRS)

    Sorensen, J. A.; Morello, S. A.; Erzberger, H.

    1979-01-01

    This paper summarizes various applications of trajectory optimization principles that have been or are being devised by both government and industrial researchers to minimize aircraft direct operating costs (DOC). These costs (time and fuel) are computed for aircraft constrained to fly over a fixed range. Optimization theory is briefly outlined, and specific algorithms which have resulted from application of this theory are described. Typical results which demonstrate use of these algorithms and the potential savings which they can produce are given. Finally, need for further trajectory optimization research is presented.

  4. Cost/Benefit Analysis of the Heat Recovery Incinerator (HRI).

    DTIC Science & Technology

    1985-09-01

    RD-0169 272 COST/BENEFIT ANALYSIS OF THE HEAT RECOVERY INCINERAR ill (HRI)(U) NAVAL CIVIL ENGINEERING LAO PORT HUENEME CA R M ROBERTS ET AL. SEP 85...Roberts & K. T. C. SwansonN O EL Sponsored By Naval Facilities Technical Note Engineering Command -:. NCOST/BENEFIT ANALYSIS 8 OF THE HEAT RECOVERY...with the HRI computer model. These sensitivity data are presented in a form to aid in the conceptual design of the optimum HRI facility for a given Navy

  5. Starship Sails Propelled by Cost-Optimized Directed Energy

    NASA Astrophysics Data System (ADS)

    Benford, J.

    Microwave and laser-propelled sails are a new class of spacecraft using photon acceleration. It is the only method of interstellar flight that has no physics issues. Laboratory demonstrations of basic features of beam-driven propulsion, flight, stability (`beam-riding'), and induced spin, have been completed in the last decade, primarily in the microwave. It offers much lower cost probes after a substantial investment in the launcher. Engineering issues are being addressed by other applications: fusion (microwave, millimeter and laser sources) and astronomy (large aperture antennas). There are many candidate sail materials: carbon nanotubes and microtrusses, beryllium, graphene, etc. For acceleration of a sail, what is the cost-optimum high power system? Here the cost is used to constrain design parameters to estimate system power, aperture and elements of capital and operating cost. From general relations for cost-optimal transmitter aperture and power, system cost scales with kinetic energy and inversely with sail diameter and frequency. So optimal sails will be larger, lower in mass and driven by higher frequency beams. Estimated costs include economies of scale. We present several starship point concepts. Systems based on microwave, millimeter wave and laser technologies are of equal cost at today's costs. The frequency advantage of lasers is cancelled by the high cost of both the laser and the radiating optic. Cost of interstellar sailships is very high, driven by current costs for radiation source, antennas and especially electrical power. The high speeds necessary for fast interstellar missions make the operating cost exceed the capital cost. Such sailcraft will not be flown until the cost of electrical power in space is reduced orders of magnitude below current levels.

  6. Solar Water Heating with Low-Cost Plastic Systems

    SciTech Connect

    2012-01-01

    Federal buildings consumed over 392,000 billion Btu of site delivered energy for buildings during FY 2007 at a total cost of $6.5 billion. Earlier data indicate that about 10% of this is used to heat water.[2] Targeting energy consumption in Federal buildings, the Energy Independence and Security Act of 2007 (EISA) requires new Federal buildings and major renovations to meet 30% of their hot water demand with solar energy, provided it is cost-effective over the life of the system. In October 2009, President Obama expanded the energy reduction and performance requirements of EISA and its subsequent regulations with his Executive Order 13514.

  7. Application of Particle Swarm Optimization Algorithm in the Heating System Planning Problem

    PubMed Central

    Ma, Rong-Jiang; Yu, Nan-Yang; Hu, Jun-Yi

    2013-01-01

    Based on the life cycle cost (LCC) approach, this paper presents an integral mathematical model and particle swarm optimization (PSO) algorithm for the heating system planning (HSP) problem. The proposed mathematical model minimizes the cost of heating system as the objective for a given life cycle time. For the particularity of HSP problem, the general particle swarm optimization algorithm was improved. An actual case study was calculated to check its feasibility in practical use. The results show that the improved particle swarm optimization (IPSO) algorithm can more preferably solve the HSP problem than PSO algorithm. Moreover, the results also present the potential to provide useful information when making decisions in the practical planning process. Therefore, it is believed that if this approach is applied correctly and in combination with other elements, it can become a powerful and effective optimization tool for HSP problem. PMID:23935429

  8. Genetic Algorithm Optimization of a Cost Competitive Hybrid Rocket Booster

    NASA Technical Reports Server (NTRS)

    Story, George

    2014-01-01

    Performance, reliability and cost have always been drivers in the rocket business. Hybrid rockets have been late entries into the launch business due to substantial early development work on liquid rockets and later on solid rockets. Slowly the technology readiness level of hybrids has been increasing due to various large scale testing and flight tests of hybrid rockets. A remaining issue is the cost of hybrids vs the existing launch propulsion systems. This paper will review the known state of the art hybrid development work to date and incorporate it into a genetic algorithm to optimize the configuration based on various parameters. A cost module will be incorporated to the code based on the weights of the components. The design will be optimized on meeting the performance requirements at the lowest cost.

  9. Genetic Algorithm Optimization of a Cost Competitive Hybrid Rocket Booster

    NASA Technical Reports Server (NTRS)

    Story, George

    2015-01-01

    Performance, reliability and cost have always been drivers in the rocket business. Hybrid rockets have been late entries into the launch business due to substantial early development work on liquid rockets and solid rockets. Slowly the technology readiness level of hybrids has been increasing due to various large scale testing and flight tests of hybrid rockets. One remaining issue is the cost of hybrids versus the existing launch propulsion systems. This paper will review the known state-of-the-art hybrid development work to date and incorporate it into a genetic algorithm to optimize the configuration based on various parameters. A cost module will be incorporated to the code based on the weights of the components. The design will be optimized on meeting the performance requirements at the lowest cost.

  10. Increase Productivity and Cost Optimization in CNC Manufacturing

    NASA Astrophysics Data System (ADS)

    Musca, Gavril; Mihalache, Andrei; Tabacaru, Lucian

    2016-11-01

    The advantage of the technological assisted design consists in easy modification of the machining technologies for obtaining machine alternation, tool changing, working parameters variation or the modification of loads to which the tools are subjected. By determining tool movement inside machining and by using tool related moving speeds needed for both positioning and manufacturing we are able to compute the required machining time for each component of the machining operation in progress. The present study describes a cost optimization model for machining operations which uses the following components: machine and its operator related cost, set-up and adjustment, unproductive costs (idle state), direct and indirect costs. By using manufacturing technologies assisted design procedures we may obtain various variants for the technological model by modifying the machining strategy, tooling, working regimes or the machine-tool that are used. Simulating those variants allows us to compare and establish the optimal manufacturing variant as well as the most productive one.

  11. On Optimizing an Archibald Rubber-Band Heat Engine.

    ERIC Educational Resources Information Center

    Mullen, J. G.; And Others

    1978-01-01

    Discusses the criteria and procedure for optimizing the performance of Archibald rubber-band heat engines by using the appropriate choice of dimensions, minimizing frictional torque, maximizing torque and balancing the rubber band system. (GA)

  12. Optimized Heat Interception for Cryogen Tank Support

    NASA Technical Reports Server (NTRS)

    Canavan, Edgar R.; Miller, F. K.

    2007-01-01

    We consider means for using the cooling available in boil-off gas to intercept heat conducted through the support structure of a cryogen tank. A one-dimensional model of the structure coupled to a gas stream gives an analytical expression for heat leak in terms of flow rate for temperature independent-properties and laminar flow. A numerical model has been developed for heat transfer on a thin cylindrical tube with an attached vent line. The model is used to determine the vent path layout that will minimize heat flow into the cryogen tank. The results are useful for a number of applications, but the one of interest in this study is the minimization of the boil-off in large cryopropellant tanks in low Earth and low lunar orbit.

  13. Optimizing Ice Thermal Storage to Reduce Energy Cost

    NASA Astrophysics Data System (ADS)

    Hall, Christopher L.

    Energy cost for buildings is an issue of concern for owners across the U.S. The bigger the building, the greater the concern. A part of this is due to the energy required to cool the building and the way in which charges are set when paying for energy consumed during different times of the day. This study will prove that designing ice thermal storage properly will minimize energy cost in buildings. The effectiveness of ice thermal storage as a means to reduce energy costs lies within transferring the time of most energy consumption from on-peak to off-peak periods. Multiple variables go into the equation of finding the optimal use of ice thermal storage and they are all judged with the final objective of minimizing monthly energy costs. This research discusses the optimal design of ice thermal storage and its impact on energy consumption, energy demand, and the total energy cost. A tool for optimal design of ice thermal storage is developed, considering variables such as chiller and ice storage sizes and charging and discharge times. The simulations take place in a four-story building and investigate the potential of Ice Thermal Storage as a resource in reducing and minimizing energy cost for cooling. The simulations test the effectiveness of Ice Thermal Storage implemented into the four-story building in ten locations across the United States.

  14. Cost Optimization Model for Business Applications in Virtualized Grid Environments

    NASA Astrophysics Data System (ADS)

    Strebel, Jörg

    The advent of Grid computing gives enterprises an ever increasing choice of computing options, yet research has so far hardly addressed the problem of mixing the different computing options in a cost-minimal fashion. The following paper presents a comprehensive cost model and a mixed integer optimization model which can be used to minimize the IT expenditures of an enterprise and help in decision-making when to outsource certain business software applications. A sample scenario is analyzed and promising cost savings are demonstrated. Possible applications of the model to future research questions are outlined.

  15. COTSAT Small Spacecraft Cost Optimization for Government and Commercial Use

    NASA Technical Reports Server (NTRS)

    Swank, Aaron J.; Bui, David; Dallara, Christopher; Ghassemieh, Shakib; Hanratty, James; Jackson, Evan; Klupar, Pete; Lindsay, Michael; Ling, Kuok; Mattei, Nicholas; Mayer, David; Quigley, Emmett; Spremo, Stevan; Young, Zion

    2009-01-01

    Cost Optimized Test of Spacecraft Avionics and Technologies (COTSAT-1) is an ongoing spacecraft research and development project at NASA Ames Research Center (ARC). The prototype spacecraft, also known as CheapSat, is the first of what could potentially be a series of rapidly produced low-cost spacecraft. The COTSAT-1 team is committed to realizing the challenging goal of building a fully functional spacecraft for $500K parts and $2.0M labor. The project's efforts have resulted in significant accomplishments within the scope of a limited budget and schedule. Completion and delivery of the flight hardware to the Engineering Directorate at NASA Ames occurred in February 2009 and a cost effective qualification program is currently under study. The COTSAT-1 spacecraft is now located at NASA Ames Research Center and is awaiting a cost effective launch opportunity. This paper highlights the advancements of the COTSAT-1 spacecraft cost reduction techniques.

  16. A new optimization approach for shell and tube heat exchangers by using electromagnetism-like algorithm (EM)

    NASA Astrophysics Data System (ADS)

    Abed, Azher M.; Abed, Issa Ahmed; Majdi, Hasan Sh.; Al-Shamani, Ali Najah; Sopian, K.

    2016-12-01

    This study proposes a new procedure for optimal design of shell and tube heat exchangers. The electromagnetism-like algorithm is applied to save on heat exchanger capital cost and designing a compact, high performance heat exchanger with effective use of the allowable pressure drop (cost of the pump). An optimization algorithm is then utilized to determine the optimal values of both geometric design parameters and maximum allowable pressure drop by pursuing the minimization of a total cost function. A computer code is developed for the optimal shell and tube heat exchangers. Different test cases are solved to demonstrate the effectiveness and ability of the proposed algorithm. Results are also compared with those obtained by other approaches available in the literature. The comparisons indicate that a proposed design procedure can be successfully applied in the optimal design of shell and tube heat exchangers. In particular, in the examined cases a reduction of total costs up to 30, 29, and 56.15 % compared with the original design and up to 18, 5.5 and 7.4 % compared with other approaches for case study 1, 2 and 3 respectively, are observed. In this work, economic optimization resulting from the proposed design procedure are relevant especially when the size/volume is critical for high performance and compact unit, moderate volume and cost are needed.

  17. BASIMO - Borehole Heat Exchanger Array Simulation and Optimization Tool

    NASA Astrophysics Data System (ADS)

    Schulte, Daniel; Rühaak, Wolfram; Welsch, Bastian; Bär, Kristian; Sass, Ingo

    2016-04-01

    Borehole heat exchangers represent a well-established technology, which pushes for new fields of applications and novel modifications. Current simulation tools cannot - or only to some extent - describe features like inclined or partly insulated boreholes unless they run fully discretized models of the borehole heat exchangers. However, fully discretized models often come at a high computational cost, especially for large arrays of borehole heat exchangers. We present a tool, which uses one dimensional thermal resistance and capacity models for the borehole heat exchangers coupled with a numerical finite element model for the subsurface heat transport. An unstructured tetrahedral mesh bypasses the limitations of structured grids for borehole path geometries, while the thermal resistance and capacity model is improved to account for borehole heat exchanger properties changing with depth. The presented tool benefits from the fast analytical solution of the thermal interactions within the boreholes while still allowing for a detailed consideration of the borehole heat exchanger properties.

  18. Reducing long-term remedial costs by transport modeling optimization.

    PubMed

    Becker, David; Minsker, Barbara; Greenwald, Robert; Zhang, Yan; Harre, Karla; Yager, Kathleen; Zheng, Chunmiao; Peralta, Richard

    2006-01-01

    The Department of Defense (DoD) Environmental Security Technology Certification Program and the Environmental Protection Agency sponsored a project to evaluate the benefits and utility of contaminant transport simulation-optimization algorithms against traditional (trial and error) modeling approaches. Three pump-and-treat facilities operated by the DoD were selected for inclusion in the project. Three optimization formulations were developed for each facility and solved independently by three modeling teams (two using simulation-optimization algorithms and one applying trial-and-error methods). The results clearly indicate that simulation-optimization methods are able to search a wider range of well locations and flow rates and identify better solutions than current trial-and-error approaches. The solutions found were 5% to 50% better than those obtained using trial-and-error (measured using optimal objective function values), with an average improvement of approximately 20%. This translated into potential savings ranging from 600,000 dollars to 10,000,000 dollars for the three sites. In nearly all cases, the cost savings easily outweighed the costs of the optimization. To reduce computational requirements, in some cases the simulation-optimization groups applied multiple mathematical algorithms, solved a series of modified subproblems, and/or fit "meta-models" such as neural networks or regression models to replace time-consuming simulation models in the optimization algorithm. The optimal solutions did not account for the uncertainties inherent in the modeling process. This project illustrates that transport simulation-optimization techniques are practical for real problems. However, applying the techniques in an efficient manner requires expertise and should involve iterative modification to the formulations based on interim results.

  19. Life cycle cost assessment of future low heat rejection engines

    NASA Technical Reports Server (NTRS)

    Petersen, D. R.

    1986-01-01

    The Adiabatic Diesel Engine Component Development (ADECD) represents a project which has the objective to accelerate the development of highway truck engines with advanced technology aimed at reduced fuel consumption. The project comprises three steps, including the synthesis of a number of engine candidate designs, the coupling of each with a number of systems for utilizing exhaust gas energy, and the evaluation of each combination in terms of desirability. Particular attention is given to the employed evaluation method and the development of this method. The objective of Life Cycle Cost (LCC) evaluation in the ADECD program was to select the best from among 42 different low heat rejection engine (LHRE)/exhaust energy recovery system configurations. The LCC model is discussed along with a maintenance cost model, the evaluation strategy, the selection of parameter ranges, and a full factorial analysis.

  20. Ecological optimization of an irreversible harmonic oscillators Carnot heat engine

    NASA Astrophysics Data System (ADS)

    Liu, Xiaowei; Chen, Lingen; Wu, Feng; Sun, Fengrui

    2009-12-01

    A model of an irreversible quantum Carnot heat engine with heat resistance, internal irreversibility and heat leakage and many non-interacting harmonic oscillators is established in this paper. Based on the quantum master equation and semi-group approach, equations of some important performance parameters, such as power output, efficiency, exergy loss rate and ecological function for the irreversible quantum Carnot heat engine are derived. The optimal ecological performance of the heat engine in the classical limit is analyzed with numerical examples. Effects of internal irreversibility and heat leakage on the ecological performance are discussed. A performance comparison of the quantum heat engine under maximum ecological function and maximum power conditions is also performed.

  1. 16 CFR Appendix I to Part 305 - Heating Performance and Cost for Central Air Conditioners

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 16 Commercial Practices 1 2013-01-01 2013-01-01 false Heating Performance and Cost for Central Air... RULEâ) Pt. 305, App. I Appendix I to Part 305—Heating Performance and Cost for Central Air Conditioners Manufacturer's rated heating capacity (Btu's/hr.) Range of HSPF's Low High Single Package Units Heat...

  2. 16 CFR Appendix I to Part 305 - Heating Performance and Cost for Central Air Conditioners

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 16 Commercial Practices 1 2011-01-01 2011-01-01 false Heating Performance and Cost for Central Air... RULEâ) Pt. 305, App. I Appendix I to Part 305—Heating Performance and Cost for Central Air Conditioners Manufacturer's rated heating capacity (Btu's/hr.) Range of HSPF's Low High Single Package Units Heat...

  3. 16 CFR Appendix I to Part 305 - Heating Performance and Cost for Central Air Conditioners

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 16 Commercial Practices 1 2012-01-01 2012-01-01 false Heating Performance and Cost for Central Air... RULEâ) Pt. 305, App. I Appendix I to Part 305—Heating Performance and Cost for Central Air Conditioners Manufacturer's rated heating capacity (Btu's/hr.) Range of HSPF's Low High Single Package Units Heat...

  4. 16 CFR Appendix I to Part 305 - Heating Performance and Cost for Central Air Conditioners

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 16 Commercial Practices 1 2010-01-01 2010-01-01 false Heating Performance and Cost for Central Air... RULEâ) Pt. 305, App. I Appendix I to Part 305—Heating Performance and Cost for Central Air Conditioners Manufacturer's rated heating capacity (Btu's/hr.) Range of HSPF's Low High Single Package Units Heat...

  5. Optimal power and efficiency of quantum Stirling heat engines

    NASA Astrophysics Data System (ADS)

    Yin, Yong; Chen, Lingen; Wu, Feng

    2017-01-01

    A quantum Stirling heat engine model is established in this paper in which imperfect regeneration and heat leakage are considered. A single particle which contained in a one-dimensional infinite potential well is studied, and the system consists of countless replicas. Each particle is confined in its own potential well, whose occupation probabilities can be expressed by the thermal equilibrium Gibbs distributions. Based on the Schrödinger equation, the expressions of power output and efficiency for the engine are obtained. Effects of imperfect regeneration and heat leakage on the optimal performance are discussed. The optimal performance region and the optimal values of important parameters of the engine cycle are obtained. The results obtained can provide some guidelines for the design of a quantum Stirling heat engine.

  6. Design optimization for cost and quality: The robust design approach

    NASA Technical Reports Server (NTRS)

    Unal, Resit

    1990-01-01

    Designing reliable, low cost, and operable space systems has become the key to future space operations. Designing high quality space systems at low cost is an economic and technological challenge to the designer. A systematic and efficient way to meet this challenge is a new method of design optimization for performance, quality, and cost, called Robust Design. Robust Design is an approach for design optimization. It consists of: making system performance insensitive to material and subsystem variation, thus allowing the use of less costly materials and components; making designs less sensitive to the variations in the operating environment, thus improving reliability and reducing operating costs; and using a new structured development process so that engineering time is used most productively. The objective in Robust Design is to select the best combination of controllable design parameters so that the system is most robust to uncontrollable noise factors. The robust design methodology uses a mathematical tool called an orthogonal array, from design of experiments theory, to study a large number of decision variables with a significantly small number of experiments. Robust design also uses a statistical measure of performance, called a signal-to-noise ratio, from electrical control theory, to evaluate the level of performance and the effect of noise factors. The purpose is to investigate the Robust Design methodology for improving quality and cost, demonstrate its application by the use of an example, and suggest its use as an integral part of space system design process.

  7. Optimization-based design of a heat flux concentrator

    PubMed Central

    Peralta, Ignacio; Fachinotti, Víctor D.; Ciarbonetti, Ángel A.

    2017-01-01

    To gain control over the diffusive heat flux in a given domain, one needs to engineer a thermal metamaterial with a specific distribution of the generally anisotropic thermal conductivity throughout the domain. Until now, the appropriate conductivity distribution was usually determined using transformation thermodynamics. By this way, only a few particular cases of heat flux control in simple domains having simple boundary conditions were studied. Thermal metamaterials based on optimization algorithm provides superior properties compared to those using the previous methods. As a more general approach, we propose to define the heat control problem as an optimization problem where we minimize the error in guiding the heat flux in a given way, taking as design variables the parameters that define the variable microstructure of the metamaterial. In the present study we numerically demonstrate the ability to manipulate heat flux by designing a device to concentrate the thermal energy to its center without disturbing the temperature profile outside it. PMID:28084451

  8. Optimization-based design of a heat flux concentrator.

    PubMed

    Peralta, Ignacio; Fachinotti, Víctor D; Ciarbonetti, Ángel A

    2017-01-13

    To gain control over the diffusive heat flux in a given domain, one needs to engineer a thermal metamaterial with a specific distribution of the generally anisotropic thermal conductivity throughout the domain. Until now, the appropriate conductivity distribution was usually determined using transformation thermodynamics. By this way, only a few particular cases of heat flux control in simple domains having simple boundary conditions were studied. Thermal metamaterials based on optimization algorithm provides superior properties compared to those using the previous methods. As a more general approach, we propose to define the heat control problem as an optimization problem where we minimize the error in guiding the heat flux in a given way, taking as design variables the parameters that define the variable microstructure of the metamaterial. In the present study we numerically demonstrate the ability to manipulate heat flux by designing a device to concentrate the thermal energy to its center without disturbing the temperature profile outside it.

  9. Optimization-based design of a heat flux concentrator

    NASA Astrophysics Data System (ADS)

    Peralta, Ignacio; Fachinotti, Víctor D.; Ciarbonetti, Ángel A.

    2017-01-01

    To gain control over the diffusive heat flux in a given domain, one needs to engineer a thermal metamaterial with a specific distribution of the generally anisotropic thermal conductivity throughout the domain. Until now, the appropriate conductivity distribution was usually determined using transformation thermodynamics. By this way, only a few particular cases of heat flux control in simple domains having simple boundary conditions were studied. Thermal metamaterials based on optimization algorithm provides superior properties compared to those using the previous methods. As a more general approach, we propose to define the heat control problem as an optimization problem where we minimize the error in guiding the heat flux in a given way, taking as design variables the parameters that define the variable microstructure of the metamaterial. In the present study we numerically demonstrate the ability to manipulate heat flux by designing a device to concentrate the thermal energy to its center without disturbing the temperature profile outside it.

  10. Optimized evaporation from a microchannel heat sink

    NASA Astrophysics Data System (ADS)

    Monazami, Reza; Haj-Hariri, Hossein

    2011-11-01

    Two-phase heat transfer devices, benefiting the unique thermal capacities of phase- change, are considered as the top choice for a wide range of applications involving cooling and temperature control. Evaporation and condensation in these devices usually take place on porous structures. It is widely accepted that they improve the evaporation rates and the overall performance of the device. The liquid menisci formed on the pores of a porous material can be viewed as the active sites of evaporation. Therefore, quantifying the rate of evaporation from a single pore can be used to calculate the total evaporation taking place in the evaporator given the density and the average size of the pores. A microchannel heat sink can be viewed as an structured porous material. In this work, an analytical model is developed to predict the evaporation rate from a liquid meniscus enclosed in a microchannel. The effects of the wall superheat and the width of the channel on the evaporation profile through the meniscus are studied. The results suggest that there is an optimum size for the width of the channel in order to maximize the thermal energy absorbed by the unit area of the heat sink as an array of microchannels.

  11. Optimization of combined endoreversible Carnot heat engines with different objectives

    NASA Astrophysics Data System (ADS)

    Cheng, Xue-Tao; Liang, Xin-Gang

    2015-06-01

    Taking the output power, thermal efficiency, and thermo-economic performance as the optimization objectives, we optimize the operation parameters of a thermodynamic system with combined endoreversible Carnot heat engines in this paper. The applicabilities of the entropy generation minimization and entransy theory to the optimizations are discussed. For the discussed cases, only the entransy loss coefficient is always agreeable to the optimization of thermal efficiency. The applicabilities of the other discussed concepts to the optimizations are conditional. Different concepts and principles are needed for different optimization objectives, and the optimization principles have their application preconditions. When the preconditions are not satisfied, the principles may be not applicable. Project supported by the National Natural Science Foundation of China (Grant No. 51376101) and the Science Fund for Creative Research Groups, China (Grant No. 51321002).

  12. The performance optimization of a gas turbine cogeneration/heat pump facility with thermal storage

    SciTech Connect

    Spakovsky, M.R. von; Curti, V.; Batato, M.

    1995-01-01

    With the push for greater energy conservation, the need for heating and/or power production is being filled by cogeneration facilities. Thus, the search for the best performance at the least cost for such multipurpose plants is made much more difficult by the fact that such facilities must meet differing goals or demands. Such a facility exists at the Ecole Polytechnique Federale de Lausanne (EPFL) and has been studied in order to find the optimum modes of operation as a function of time for variations in both the heating and electrical demands this facility must meet. The results of this study are presented here. The plant itself provides heat and electricity for both the EPFL and the University of Lausanne and is projected to supply electricity to the exterior utility grid provided it can be shown to be economically viable. The plant`s primary components include two gas turbines, a heat recovery system, two heat pumps, a set of heat storage tanks, and both medium and low-temperature district heating networks. In order to find the optimum mode of operation, a mixed-integer linear programming approach was used, which balances the competing costs of operation and minimizes these costs subject to the operational constraints placed on the system. The effects of both the cost of the fuel and the costs of electricity sold and bought on the best performance of the system are evaluated. In addition, the important features of the modeling process are discussed, in particular the heat storage tanks, which complicate the optimization of the series of steady-state models used to model the overall quasi-steady-state behavior of the system.

  13. Simple model for predicting microchannel heat sink performance and optimization

    NASA Astrophysics Data System (ADS)

    Tsai, Tsung-Hsun; Chein, Reiyu

    2012-05-01

    A simple model was established to predict microchannel heat sink performance based on energy balance. Both hydrodynamically and thermally developed effects were included. Comparisons with the experimental data show that this model provides satisfactory thermal resistance prediction. The model is further extended to carry out geometric optimization on the microchannel heat sink. The results from the simple model are in good agreement as compared with those obtained from three-dimensional simulations.

  14. Parametric Optimization of Thermoelectric Generators for Waste Heat Recovery

    NASA Astrophysics Data System (ADS)

    Huang, Shouyuan; Xu, Xianfan

    2016-10-01

    This paper presents a methodology for design optimization of thermoelectric-based waste heat recovery systems called thermoelectric generators (TEGs). The aim is to maximize the power output from thermoelectrics which are used as add-on modules to an existing gas-phase heat exchanger, without negative impacts, e.g., maintaining a minimum heat dissipation rate from the hot side. A numerical model is proposed for TEG coupled heat transfer and electrical power output. This finite-volume-based model simulates different types of heat exchangers, i.e., counter-flow and cross-flow, for TEGs. Multiple-filled skutterudites and bismuth-telluride-based thermoelectric modules (TEMs) are applied, respectively, in higher and lower temperature regions. The response surface methodology is implemented to determine the optimized TEG size along and across the flow direction and the height of thermoelectric couple legs, and to analyze their covariance and relative sensitivity. A genetic algorithm is employed to verify the globality of the optimum. The presented method will be generally useful for optimizing heat-exchanger-based TEG performance.

  15. Exergy optimization in a steady moving bed heat exchanger.

    PubMed

    Soria-Verdugo, A; Almendros-Ibáñez, J A; Ruiz-Rivas, U; Santana, D

    2009-04-01

    This work provides an energy and exergy optimization analysis of a moving bed heat exchanger (MBHE). The exchanger is studied as a cross-flow heat exchanger where one of the phases is a moving granular medium. The optimal MBHE dimensions and the optimal particle diameter are obtained for a range of incoming fluid flow rates. The analyses are carried out over operation data of the exchanger obtained in two ways: a numerical simulation of the steady-state problem and an analytical solution of the simplified equations, neglecting the conduction terms. The numerical simulation considers, for the solid, the convection heat transfer to the fluid and the diffusion term in both directions, and for the fluid only the convection heat transfer to the solid. The results are compared with a well-known analytical solution (neglecting conduction effects) for the temperature distribution in the exchanger. Next, the analytical solution is used to derive an expression for the exergy destruction. The optimal length of the MBHE depends mainly on the flow rate and does not depend on particle diameter unless they become very small (thus increasing sharply the pressure drop). The exergy optimal length is always smaller than the thermal one, although the difference is itself small.

  16. Optimal Heat Collection Element Shapes for Parabolic Trough Concentrators

    SciTech Connect

    Bennett, C

    2007-11-15

    For nearly 150 years, the cross section of the heat collection tubes used at the focus of parabolic trough solar concentrators has been circular. This type of tube is obviously simple and easily fabricated, but it is not optimal. It is shown in this article that the optimal shape, assuming a perfect parabolic figure for the concentrating mirror, is instead oblong, and is approximately given by a pair of facing parabolic segments.

  17. Adjoint analyses of enhanced solidification for shape optimization in conjugate heat transfer problem

    NASA Astrophysics Data System (ADS)

    Morimoto, Kenichi; Kinoshita, Hidenori; Suzuki, Yuji

    2016-11-01

    In the present study, an adjoint-based shape-optimization method has been developed for designing extended heat transfer surfaces in conjugate heat transfer problems. Here we specifically consider heat conduction-dominated solidification problem under different thermal boundary conditions: (i) the isothermal condition, and (ii) the conjugate condition with thermal coupling between the solidified liquid and the solid wall inside the domain bounded by the extended heat transfer surface. In the present shape-optimization scheme, extended heat transfer surfaces are successively refined in a local way based on the variational information of a cost functional with respect to the shape modification. In the computation of the developed scheme, a meshless method is employed for dealing with the complex boundary shape. For high-resolution analyses with boundary-fitted node arrangement, we have introduced a bubble-mesh method combined with a high-efficiency algorithm for searching neighboring bubbles within a cut-off distance. The present technique can be easily applied to convection problems including high Reynolds number flow. We demonstrate, for the isothermal boundary condition, that the present optimization leads to tree-like fin shapes, which achieve the temperature field with global similarity for different initial fin shapes. We will also show the computational results for the conjugate condition, which would regularize the present optimization due to the fin-efficiency effect.

  18. Numerical Modeling and Optimization of Warm-water Heat Sinks

    NASA Astrophysics Data System (ADS)

    Hadad, Yaser; Chiarot, Paul

    2015-11-01

    For cooling in large data-centers and supercomputers, water is increasingly replacing air as the working fluid in heat sinks. Utilizing water provides unique capabilities; for example: higher heat capacity, Prandtl number, and convection heat transfer coefficient. The use of warm, rather than chilled, water has the potential to provide increased energy efficiency. The geometric and operating parameters of the heat sink govern its performance. Numerical modeling is used to examine the influence of geometry and operating conditions on key metrics such as thermal and flow resistance. This model also facilitates studies on cooling of electronic chip hot spots and failure scenarios. We report on the optimal parameters for a warm-water heat sink to achieve maximum cooling performance.

  19. 16 CFR Appendix I to Part 305 - Heating Performance and Cost for Central Air Conditioners

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 16 Commercial Practices 1 2014-01-01 2014-01-01 false Heating Performance and Cost for Central Air... CONSERVATION ACT (âENERGY LABELING RULEâ) Pt. 305, App. I Appendix I to Part 305—Heating Performance and Cost for Central Air Conditioners Manufacturer's rated heating capacity (Btu's/hr.) Range of HSPF's...

  20. Optimizing bulk milk dioxin monitoring based on costs and effectiveness.

    PubMed

    Lascano-Alcoser, V H; Velthuis, A G J; van der Fels-Klerx, H J; Hoogenboom, L A P; Oude Lansink, A G J M

    2013-07-01

    Dioxins are environmental pollutants, potentially present in milk products, which have negative consequences for human health and for the firms and farms involved in the dairy chain. Dioxin monitoring in feed and food has been implemented to detect their presence and estimate their levels in food chains. However, the costs and effectiveness of such programs have not been evaluated. In this study, the costs and effectiveness of bulk milk dioxin monitoring in milk trucks were estimated to optimize the sampling and pooling monitoring strategies aimed at detecting at least 1 contaminated dairy farm out of 20,000 at a target dioxin concentration level. Incidents of different proportions, in terms of the number of contaminated farms, and concentrations were simulated. A combined testing strategy, consisting of screening and confirmatory methods, was assumed as well as testing of pooled samples. Two optimization models were built using linear programming. The first model aimed to minimize monitoring costs subject to a minimum required effectiveness of finding an incident, whereas the second model aimed to maximize the effectiveness for a given monitoring budget. Our results show that a high level of effectiveness is possible, but at high costs. Given specific assumptions, monitoring with 95% effectiveness to detect an incident of 1 contaminated farm at a dioxin concentration of 2 pg of toxic equivalents/g of fat [European Commission's (EC) action level] costs €2.6 million per month. At the same level of effectiveness, a 73% cost reduction is possible when aiming to detect an incident where 2 farms are contaminated at a dioxin concentration of 3 pg of toxic equivalents/g of fat (EC maximum level). With a fixed budget of €40,000 per month, the probability of detecting an incident with a single contaminated farm at a dioxin concentration equal to the EC action level is 4.4%. This probability almost doubled (8.0%) when aiming to detect the same incident but with a dioxin

  1. VARYING THE COSTS OF SUNK COSTS: OPTIMAL AND NON-OPTIMAL CHOICES IN A SUNK-COST TASK WITH HUMANS

    PubMed Central

    Avila S., Raul; Yankelevitz, Rachelle L.; Gonzalez, Juan C.; Hackenberg, Timothy D.

    2014-01-01

    Twelve adult human subjects were exposed to a sunk-cost procedure with two options: a mixed-ratio schedule of points later exchangeable for money, and an escape schedule that cancelled the current trial and initiated a new one. The mixed ratio included four values, arranged probabilistically in such a way that the expected ratios favored either persistence or escape. These probabilities were varied systematically on a within-subject basis across conditions. Absolute ratio size was thus varied across four groups of three subjects each, yielding unique combinations of expected ratios from escaping and persisting. When the differences between escaping and persisting differed the least, subjects tended to persist, committing the sunk-cost error. When the differences between persisting and escaping differed by a larger margin, choice patterns tended toward optimal—escaping or persisting as a function of the contingencies. These findings demonstrate that sunk-cost decision-making errors in humans are sensitive to their relative costs and benefits, and illustrate a promising set of methods for bringing such behavior under experimental control in the laboratory. PMID:24019009

  2. A Low Cost Structurally Optimized Design for Diverse Filter Types

    PubMed Central

    Kazmi, Majida; Aziz, Arshad; Akhtar, Pervez; Ikram, Nassar

    2016-01-01

    A wide range of image processing applications deploys two dimensional (2D)-filters for performing diversified tasks such as image enhancement, edge detection, noise suppression, multi scale decomposition and compression etc. All of these tasks require multiple type of 2D-filters simultaneously to acquire the desired results. The resource hungry conventional approach is not a viable option for implementing these computationally intensive 2D-filters especially in a resource constraint environment. Thus it calls for optimized solutions. Mostly the optimization of these filters are based on exploiting structural properties. A common shortcoming of all previously reported optimized approaches is their restricted applicability only for a specific filter type. These narrow scoped solutions completely disregard the versatility attribute of advanced image processing applications and in turn offset their effectiveness while implementing a complete application. This paper presents an efficient framework which exploits the structural properties of 2D-filters for effectually reducing its computational cost along with an added advantage of versatility for supporting diverse filter types. A composite symmetric filter structure is introduced which exploits the identities of quadrant and circular T-symmetries in two distinct filter regions simultaneously. These T-symmetries effectually reduce the number of filter coefficients and consequently its multipliers count. The proposed framework at the same time empowers this composite filter structure with additional capabilities of realizing all of its Ψ-symmetry based subtypes and also its special asymmetric filters case. The two-fold optimized framework thus reduces filter computational cost up to 75% as compared to the conventional approach as well as its versatility attribute not only supports diverse filter types but also offers further cost reduction via resource sharing for sequential implementation of diversified image

  3. Linear versus quadratic portfolio optimization model with transaction cost

    NASA Astrophysics Data System (ADS)

    Razak, Norhidayah Bt Ab; Kamil, Karmila Hanim; Elias, Siti Masitah

    2014-06-01

    Optimization model is introduced to become one of the decision making tools in investment. Hence, it is always a big challenge for investors to select the best model that could fulfill their goal in investment with respect to risk and return. In this paper we aims to discuss and compare the portfolio allocation and performance generated by quadratic and linear portfolio optimization models namely of Markowitz and Maximin model respectively. The application of these models has been proven to be significant and popular among others. However transaction cost has been debated as one of the important aspects that should be considered for portfolio reallocation as portfolio return could be significantly reduced when transaction cost is taken into consideration. Therefore, recognizing the importance to consider transaction cost value when calculating portfolio' return, we formulate this paper by using data from Shariah compliant securities listed in Bursa Malaysia. It is expected that, results from this paper will effectively justify the advantage of one model to another and shed some lights in quest to find the best decision making tools in investment for individual investors.

  4. Optimal heat pumps for solar-assisted heat-pump systems

    NASA Astrophysics Data System (ADS)

    Catan, M. A.

    Work at Brookhaven National Laboratory (BNL) investigates the design of optimal heat pumps for solar assisted heat pump (SAPH) systems. Heat pump designs suitable for two generic systems, identified in the course of recent analytical work, are being studied. These are series SAHP systems operating at evaporator temperatures in the -5 to 10 C range and those operating at evaporator temperatures in the 10 to 35 C range. A heat pump simulator has been constructed with liquid based source subsystem and two load subsystems, one for testing air cooled condensers and one for testing water cooled condensers. Heat pumps tested were composed of various components including several types of variable and fixed capacity compressors, two types of expansion devices, and heat exchangers varying in size and type.

  5. Final draft: IEA Task 1. Report on Subtask D, optimization of solar heating and cooling systems

    SciTech Connect

    Freeman, T.L.

    1981-03-01

    A review of general techniques and specific methods useful in the optimization of solar heating and cooling systems is undertaken. A discussion of the state-of-the-art and the principal problems in both the simplified thermal performance analysis and economic analysis portions of the optimization problem are presented. Sample economic analyses are performed using several widely used economic criteria. The predicted thermal results of one typical, widely used simplified method is compared to detailed simulation results. A methodology for and the results of a sensitivity study of key economic parameters in the life cycle cost method are presented. Finally, a simple graphical optimization technique based on the life cycle cost method is proposed.

  6. Final draft: IEA task 1. Report on subtask D, optimization of solar heating and cooling systems

    NASA Astrophysics Data System (ADS)

    Freeman, T. L.

    1981-03-01

    A review of general techniques and specific methods useful in the optimization of solar heating and cooling systems is undertaken. A discussion of the state of the art and the principal problems in both the simplified thermal performance analysis and economic analysis portions of the optimization problem are presented. Sample economic analyses are performed using several widely used economic criteria. The predicted thermal results of one typical, widely used simplified method is compared to detailed simulation results. A methodology for and the results of a sensitivity study of key economic parameters in the life cycle cost method are presented. Finally, a simple graphical optimization technique based on the life cycle cost method is proposed.

  7. Optimal Number of Thermoelectric Couples in a Heat Pipe Assisted Thermoelectric Generator for Waste Heat Recovery

    NASA Astrophysics Data System (ADS)

    Liu, Tongjun; Wang, Tongcai; Luan, Weiling; Cao, Qimin

    2017-01-01

    Waste heat recovery through thermoelectric generators is a promising way to improve energy conversion efficiency. This paper proposes a type of heat pipe assisted thermoelectric generator (HP-TEG) system. The expandable evaporator and condenser surface of the heat pipe facilitates the intensive assembly of thermoelectric (TE) modules to compose a compact device. Compared with a conventional layer structure thermoelectric generator, this system is feasible for the installment of more TE couples, thus increasing power output. To investigate the performance of the HP-TEG and the optimal number of TE couples, a theoretical model was presented and verified by experiment results. Further theoretical analysis results showed the performance of the HP-TEG could be further improved by optimizing the parameters, including the inlet air temperature, the thermal resistance of the heating section, and thermal resistance of the cooling structure. Moreover, applying a proper number of TE couples is important to acquire the best power output performance.

  8. Additive Manufacturing for Cost Efficient Production of Compact Ceramic Heat Exchangers and Recuperators

    SciTech Connect

    Shulman, Holly; Ross, Nicole

    2015-10-30

    An additive manufacture technique known as laminated object manufacturing (LOM) was used to fabricate compact ceramic heat exchanger prototypes. LOM uses precision CO2 laser cutting of ceramic green tapes, which are then precision stacked to build a 3D object with fine internal features. Modeling was used to develop prototype designs and predict the thermal response, stress, and efficiency in the ceramic heat exchangers. Build testing and materials analyses were used to provide feedback for the design selection. During this development process, laminated object manufacturing protocols were established. This included laser optimization, strategies for fine feature integrity, lamination fluid control, green handling, and firing profile. Three full size prototypes were fabricated using two different designs. One prototype was selected for performance testing. During testing, cross talk leakage prevented the application of a high pressure differential, however, the prototype was successful at withstanding the high temperature operating conditions (1300 °F). In addition, analysis showed that the bulk of the part did not have cracks or leakage issues. This led to the development of a module method for next generation LOM heat exchangers. A scale-up cost analysis showed that given a purpose built LOM system, these ceramic heat exchangers would be affordable for the applications.

  9. System optimization of a heat-switch-based electrocaloric heat pump

    NASA Astrophysics Data System (ADS)

    Smullin, Sylvia J.; Wang, Yunda; Schwartz, David E.

    2015-08-01

    Realization of the potential of electrocaloric heat pumps includes consideration of not only material properties but also device characteristics and cycle operation. We present detailed models and analysis that elucidate the key parameters for performance optimization. We show that the temperature lift, cooling power, and efficiency of a system driven by heat switches depend on system operating conditions and the combined thermal properties of both the heat switches and the electrocaloric capacitor. We show experimental results that validate the models and draw conclusions about building high-performance systems.

  10. Cost-Optimal Pathways to 75% Fuel Reduction in Remote Alaskan Villages

    SciTech Connect

    Simpkins, Travis; Cutler, Dylan; Hirsch, Brian; Olis, Dan; Anderson, Kate

    2015-08-01

    There are thousands of isolated, diesel-powered microgrids that deliver energy to remote communities around the world at very high energy costs. The Remote Communities Renewable Energy program aims to help these communities reduce their fuel consumption and lower their energy costs through the use of high penetration renewable energy. As part of this program, the REopt modeling platform for energy system integration and optimization was used to analyze cost-optimal pathways toward achieving a combined 75% reduction in diesel fuel and fuel oil consumption in a select Alaskan village. In addition to the existing diesel generator and fuel oil heating technologies, the model was able to select from among wind, battery storage, and dispatchable electric heaters to meet the electrical and thermal loads. The model results indicate that while 75% fuel reduction appears to be technically feasible it may not be economically viable at this time. When the fuel reduction target was relaxed, the results indicate that by installing high-penetration renewable energy, the community could lower their energy costs by 21% while still reducing their fuel consumption by 54%.

  11. Cost-Optimal Pathways to 75% Fuel Reduction in Remote Alaskan Villages: Preprint

    SciTech Connect

    Simpkins, Travis; Cutler, Dylan; Hirsch, Brian; Olis, Dan; Anderson, Kate

    2015-10-28

    There are thousands of isolated, diesel-powered microgrids that deliver energy to remote communities around the world at very high energy costs. The Remote Communities Renewable Energy program aims to help these communities reduce their fuel consumption and lower their energy costs through the use of high penetration renewable energy. As part of this program, the REopt modeling platform for energy system integration and optimization was used to analyze cost-optimal pathways toward achieving a combined 75% reduction in diesel fuel and fuel oil consumption in a select Alaskan village. In addition to the existing diesel generator and fuel oil heating technologies, the model was able to select from among wind, battery storage, and dispatchable electric heaters to meet the electrical and thermal loads. The model results indicate that while 75% fuel reduction appears to be technically feasible it may not be economically viable at this time. When the fuel reduction target was relaxed, the results indicate that by installing high-penetration renewable energy, the community could lower their energy costs by 21% while still reducing their fuel consumption by 54%.

  12. Urban water infrastructure optimization to reduce environmental impacts and costs.

    PubMed

    Lim, Seong-Rin; Suh, Sangwon; Kim, Jung-Hoon; Park, Hung Suck

    2010-01-01

    Urban water planning and policy have been focusing on environmentally benign and economically viable water management. The objective of this study is to develop a mathematical model to integrate and optimize urban water infrastructures for supply-side planning and policy: freshwater resources and treated wastewater are allocated to various water demand categories in order to reduce contaminants in the influents supplied for drinking water, and to reduce consumption of the water resources imported from the regions beyond a city boundary. A case study is performed to validate the proposed model. An optimal urban water system of a metropolitan city is calculated on the basis of the model and compared to the existing water system. The integration and optimization decrease (i) average concentrations of the influents supplied for drinking water, which can improve human health and hygiene; (ii) total consumption of water resources, as well as electricity, reducing overall environmental impacts; (iii) life cycle cost; and (iv) water resource dependency on other regions, improving regional water security. This model contributes to sustainable urban water planning and policy.

  13. Tool Steel Heat Treatment Optimization Using Neural Network Modeling

    NASA Astrophysics Data System (ADS)

    Podgornik, Bojan; Belič, Igor; Leskovšek, Vojteh; Godec, Matjaz

    2016-11-01

    Optimization of tool steel properties and corresponding heat treatment is mainly based on trial and error approach, which requires tremendous experimental work and resources. Therefore, there is a huge need for tools allowing prediction of mechanical properties of tool steels as a function of composition and heat treatment process variables. The aim of the present work was to explore the potential and possibilities of artificial neural network-based modeling to select and optimize vacuum heat treatment conditions depending on the hot work tool steel composition and required properties. In the current case training of the feedforward neural network with error backpropagation training scheme and four layers of neurons (8-20-20-2) scheme was based on the experimentally obtained tempering diagrams for ten different hot work tool steel compositions and at least two austenitizing temperatures. Results show that this type of modeling can be successfully used for detailed and multifunctional analysis of different influential parameters as well as to optimize heat treatment process of hot work tool steels depending on the composition. In terms of composition, V was found as the most beneficial alloying element increasing hardness and fracture toughness of hot work tool steel; Si, Mn, and Cr increase hardness but lead to reduced fracture toughness, while Mo has the opposite effect. Optimum concentration providing high KIc/HRC ratios would include 0.75 pct Si, 0.4 pct Mn, 5.1 pct Cr, 1.5 pct Mo, and 0.5 pct V, with the optimum heat treatment performed at lower austenitizing and intermediate tempering temperatures.

  14. Waste heat boiler optimization by entropy minimization principle

    SciTech Connect

    Reddy, B.V.; Murali, J.; Satheesh, V.S.; Nag, P.K.

    1996-12-31

    A second law analysis has been undertaken for a waste heat boiler having an economizer, evaporator and superheater. Following the principle of minimization of entropy generation, a general equation for entropy generation number is derived, which incorporates all the operating variables. By differentiating the entropy generation number equation with respect to the operating parameters, various optimization parameters can be obtained. Few illustrations have been made to see the effect of various parameters on entropy generation number.

  15. Optimizing Structure of LED Light Bulb for Heat Transfer

    NASA Astrophysics Data System (ADS)

    Kobayashi, T.; Itami, D.; Hashimoto, R.; Takashina, T.; Kanematsu, H.; Mizuta, K.; Utsumi, Y.

    2013-04-01

    In this paper, in order to optimize the heat transfer structure of LED light bulb, the effects of various parameters on the temperature of the LED device were systematically analyzed, and a design guideline was shown. Although LED device has become popular due to its high-efficiency and long life, the design issues on the heat transfer structure of LED light bulbs has still remained. Because the original efficiency and life of the LED device can not be obtained due to the local temperature rise of LED element and the surrounding polymer molding material. Therefore, heat transfer analysis by finite element method was conducted systematically by changing parameters such as the shape, number and thickness of the radiating fin of the LED. As a result, advantage of open type structure was shown, and the proper design guidance for the structure of the fin shape was obtained.

  16. Optimization of a localized surface plasmon resonance biosensor for heat shock protein 70

    NASA Astrophysics Data System (ADS)

    Denomme, R. C.; Young, Z.; Brock, L.; Nieva, P. M.; Vijayan, M. M.

    2012-03-01

    Localized surface plasmon resonance, a property characteristic of metal nanoparticles, is a promising technique for the development of low cost, rapid, and portable biosensors for a variety of medical diagnostic applications. In order to meet the demanding detection limits required for many such applications, performance improvements are required. Designing nanoparticle structures to maximize refractive index sensitivity and optimize the electromagnetic field decay length is one approach to achieving better performance. However, experimentally finding the optimal nanoparticle structure, as has been done in the past, is time consuming and costly, and needs to be done for each biomolecule of interest. Instead, simulations can be used to find the optimal nanoparticle design prior to fabrication. In this paper, we present a numerical modeling technique that allows the design of optimal nanoparticles for LSPR biosensors, and report on the effect of the size and shape of gold nanoparticles on the sensitivity and decay length. The results are used to determine the optimal nanoparticle geometry for an LSPR immunosensor for heat shock protein 70, an important protein with applications in medical and wildlife diagnostics. Our simulations show an improvement of 373% in sensor response when using the optimal configuration, showcasing the significant advantages of proper nanoparticle design.

  17. Impacts of Various Characteristics of Electricity and Heat Demand on the Optimal Configuration of a Microgrid

    NASA Astrophysics Data System (ADS)

    Bando, Shigeru; Watanabe, Hiroki; Asano, Hiroshi; Tsujita, Shinsuke

    A methodology was developed to design the number and capacity for each piece of equipment (e.g. gas engines, batteries, thermal storage tanks) in microgrids with combined heat and power systems. We analyzed three types of microgrids; the first one consists of an office building and an apartment, the second one consists of a hospital and an apartment, the third one consists of a hotel, office and retails. In the methodology, annual cost is minimized by considering the partial load efficiency of a gas engine and its scale economy, and the optimal number and capacity of each piece of equipment and the annual operational schedule are determined by using the optimal planning method. Based on calculations using this design methodology, it is found that the optimal number of gas engines is determined by the ratio of bottom to peak of the electricity demand and the ratio of heat to electricity demand. The optimal capacity of a battery required to supply electricity for a limited time during a peak demand period is auxiliary. The thermal storage tank for space cooling and space heating is selected to minimize the use of auxiliary equipment such as a gas absorption chiller.

  18. Low Cost Advanced Thermoelectric (TE) Technology for Automotive Waste Heat Recovery

    NASA Astrophysics Data System (ADS)

    Meisner, G. P.

    2014-03-01

    Low cost, fully integrated TE generators (TEGs) to recover waste heat from vehicle exhaust will reduce transportation sector energy consumption and emissions. TEGs will be the first application of high-temperature TE materials for high-volume use and establish new industrial sectors with scaled up production capability of TEG materials and components. We will create a potential supply chain for practical automotive TEGs and identify manufacturing and assembly processes for large scale production of TEG materials and components. Our work focusses on several innovative R&D paths: (1) enhanced TE material performance by doping and compositional tuning, (2) optimized TE material fabrication and processing to reduce thermal conductivity and improve fracture strength, (3) high volume production for successful skutterudite commercialization, (4) new material, nanostructure, and nanoscale approaches to reduce thermal interface and electrical contact resistances, (5) innovative heat exchangers for high efficiency heat flows and optimum temperature profiles despite highly variable exhaust gas operating conditions, (6) new modeling and simulation tools, and (7) inexpensive materials for thermal insulation and coatings for TE encapsulation. Recent results will be presented. Supported by the U.S. DOE Vehicle Technology Program.

  19. Refrigeration Playbook. Heat Reclaim; Optimizing Heat Rejection and Refrigeration Heat Reclaim for Supermarket Energy Conservation

    SciTech Connect

    Reis, Chuck; Nelson, Eric; Armer, James; Johnson, Tim; Hirsch, Adam; Doebber, Ian

    2015-03-01

    The purpose of this playbook and accompanying spreadsheets is to generalize the detailed CBP analysis and to put tools in the hands of experienced refrigeration designers to evaluate multiple applications of refrigeration waste heat reclaim across the United States. Supermarkets with large portfolios of similar buildings can use these tools to assess the impact of large-scale implementation of heat reclaim systems. In addition, the playbook provides best practices for implementing heat reclaim systems to achieve the best long-term performance possible. It includes guidance on operations and maintenance as well as measurement and verification.

  20. Optimal Investment Under Transaction Costs: A Threshold Rebalanced Portfolio Approach

    NASA Astrophysics Data System (ADS)

    Tunc, Sait; Donmez, Mehmet Ali; Kozat, Suleyman Serdar

    2013-06-01

    We study optimal investment in a financial market having a finite number of assets from a signal processing perspective. We investigate how an investor should distribute capital over these assets and when he should reallocate the distribution of the funds over these assets to maximize the cumulative wealth over any investment period. In particular, we introduce a portfolio selection algorithm that maximizes the expected cumulative wealth in i.i.d. two-asset discrete-time markets where the market levies proportional transaction costs in buying and selling stocks. We achieve this using "threshold rebalanced portfolios", where trading occurs only if the portfolio breaches certain thresholds. Under the assumption that the relative price sequences have log-normal distribution from the Black-Scholes model, we evaluate the expected wealth under proportional transaction costs and find the threshold rebalanced portfolio that achieves the maximal expected cumulative wealth over any investment period. Our derivations can be readily extended to markets having more than two stocks, where these extensions are pointed out in the paper. As predicted from our derivations, we significantly improve the achieved wealth over portfolio selection algorithms from the literature on historical data sets.

  1. Cost Optimal Elastic Auto-Scaling in Cloud Infrastructure

    NASA Astrophysics Data System (ADS)

    Mukhopadhyay, S.; Sidhanta, S.; Ganguly, S.; Nemani, R. R.

    2014-12-01

    Today, elastic scaling is critical part of leveraging cloud. Elastic scaling refers to adding resources only when it is needed and deleting resources when not in use. Elastic scaling ensures compute/server resources are not over provisioned. Today, Amazon and Windows Azure are the only two platform provider that allow auto-scaling of cloud resources where servers are automatically added and deleted. However, these solution falls short of following key features: A) Requires explicit policy definition such server load and therefore lacks any predictive intelligence to make optimal decision; B) Does not decide on the right size of resource and thereby does not result in cost optimal resource pool. In a typical cloud deployment model, we consider two types of application scenario: A. Batch processing jobs → Hadoop/Big Data case B. Transactional applications → Any application that process continuous transactions (Requests/response) In reference of classical queuing model, we are trying to model a scenario where servers have a price and capacity (size) and system can add delete servers to maintain a certain queue length. Classical queueing models applies to scenario where number of servers are constant. So we cannot apply stationary system analysis in this case. We investigate the following questions 1. Can we define Job queue and use the metric to define such a queue to predict the resource requirement in a quasi-stationary way? Can we map that into an optimal sizing problem? 2. Do we need to get into a level of load (CPU/Data) on server level to characterize the size requirement? How do we learn that based on Job type?

  2. Structural optimization for heat detection of DNA thermosequencing platform using finite element analysis

    PubMed Central

    Esfandyarpour, Hesaam; Zheng, Bo; Pease, R. Fabian W.; Davis, Ronald W.

    2008-01-01

    For the past three decades, Sanger’s method has been the primary DNA sequencing technology; however, inherent limitations in cost and complexity have limited its usage in personalized medicine and ecological studies. A new technology called “thermosequencing” can potentially reduce both the cost and complexity of DNA sequencing by using a microfluidic platform [Esfandyarpour, Pease, and Davis, J. Vac. Sci. Technol. B26, 661 (2008)]. To optimize the efficiency of the technology, finite element analysis was used to model the thermosequencing system by simulating the DNA incorporation reaction series and the resulting product concentration and heat production. Different models of the thermosequencing platform were created to simulate the effects of the materials surrounding the system, to optimize the geometry of the system, and to concentrate reaction heat into specific regions for detection in the real system. The resulting concentrations of reaction products were used to calibrate the reaction speed and to design the heat sensors in the thermosequencing technology. We recommend a modified gated structure for the microfluidic detection platform by using control valves and show how this new platform could dramatically improve the detection efficiency. PMID:19693405

  3. Convex optimization of MRI exposure for mitigation of RF-heating from active medical implants

    NASA Astrophysics Data System (ADS)

    Córcoles, Juan; Zastrow, Earl; Kuster, Niels

    2015-09-01

    Local RF-heating of elongated medical implants during magnetic resonance imaging (MRI) may pose a significant health risk to patients. The actual patient risk depends on various parameters including RF magnetic field strength and frequency, MR coil design, patient’s anatomy, posture, and imaging position, implant location, RF coupling efficiency of the implant, and the bio-physiological responses associated with the induced local heating. We present three constrained convex optimization strategies that incorporate the implant’s RF-heating characteristics, for the reduction of local heating of medical implants during MRI. The study emphasizes the complementary performances of the different formulations. The analysis demonstrates that RF-induced heating of elongated metallic medical implants can be carefully controlled and balanced against MRI quality. A reduction of heating of up to 25 dB can be achieved at the cost of reduced uniformity in the magnitude of the B1+ field of less than 5%. The current formulations incorporate a priori knowledge of clinically-specific parameters, which is assumed to be available. Before these techniques can be applied practically in the broader clinical context, further investigations are needed to determine whether reduced access to a priori knowledge regarding, e.g. the patient’s anatomy, implant routing, RF-transmitter, and RF-implant coupling, can be accepted within reasonable levels of uncertainty.

  4. Convex optimization of MRI exposure for mitigation of RF-heating from active medical implants.

    PubMed

    Córcoles, Juan; Zastrow, Earl; Kuster, Niels

    2015-09-21

    Local RF-heating of elongated medical implants during magnetic resonance imaging (MRI) may pose a significant health risk to patients. The actual patient risk depends on various parameters including RF magnetic field strength and frequency, MR coil design, patient's anatomy, posture, and imaging position, implant location, RF coupling efficiency of the implant, and the bio-physiological responses associated with the induced local heating. We present three constrained convex optimization strategies that incorporate the implant's RF-heating characteristics, for the reduction of local heating of medical implants during MRI. The study emphasizes the complementary performances of the different formulations. The analysis demonstrates that RF-induced heating of elongated metallic medical implants can be carefully controlled and balanced against MRI quality. A reduction of heating of up to 25 dB can be achieved at the cost of reduced uniformity in the magnitude of the B(1)(+) field of less than 5%. The current formulations incorporate a priori knowledge of clinically-specific parameters, which is assumed to be available. Before these techniques can be applied practically in the broader clinical context, further investigations are needed to determine whether reduced access to a priori knowledge regarding, e.g. the patient's anatomy, implant routing, RF-transmitter, and RF-implant coupling, can be accepted within reasonable levels of uncertainty.

  5. Acoustic Optimization of Automotive Exhaust Heat Thermoelectric Generator

    NASA Astrophysics Data System (ADS)

    Su, C. Q.; Ye, B. Q.; Guo, X.; Hui, P.

    2012-06-01

    The potential for thermoelectric exhaust heat recovery in vehicles has been increasing with recent advances in the efficiency of thermoelectric generators (TEGs). This study analyzes the acoustic attenuation performance of exhaust-based TEGs. The acoustic characteristics of two different thermal designs of exhaust gas heat exchanger in TEGs are discussed in terms of transmission loss and acoustic insertion loss. GT-Power simulations and bench tests on a dynamometer with a high-performance production engine are carried out. Results indicate that the acoustic attenuation of TEGs could be determined and optimized. In addition, the feasibility of integration of exhaust-based TEGs and engine mufflers into the exhaust line is tested, which can help to reduce space and improve vehicle integration.

  6. Optimization of the electrically heated catalyst for emission purification efficiency

    SciTech Connect

    Jeong, L.; Jang, J.; Yeo, G.; Kim, Y.

    1996-09-01

    It is well known that the EHC (Electrically Heated Catalyst) is very effective for the reduction of cold-start hydrocarbon emissions. To optimize EHC applications for LEV (Low Emission Vehicle) and ULEV (Ultra Low Emission Vehicle) standards, the effects of heating and secondary air injection on the emission purification efficiency in FTP (Federal Test Procedure) were evaluated with three different EHC system configurations. The exhaust manifold location EHC system in which the EHC with a light-off catalyst is installed near the exhaust manifold, yields 0.038g/mile of THC (Total Hydrocarbon emissions) when the test was performed according to the FTP with an engine-aged condition equivalent to 50,000 miles. Therefore, the ULEV standards could be achieved through the system. A new battery system for the EHC and a single battery system for vehicle application were evaluated. Evaluation of the Ni-MH battery for EHC system is included.

  7. Color tunable low cost transparent heat reflector using copper and titanium oxide for energy saving application.

    PubMed

    Dalapati, Goutam Kumar; Masudy-Panah, Saeid; Chua, Sing Teng; Sharma, Mohit; Wong, Ten It; Tan, Hui Ru; Chi, Dongzhi

    2016-02-05

    Multilayer coating structure comprising a copper (Cu) layer sandwiched between titanium dioxide (TiO2) were demonstrated as a transparent heat reflecting (THR) coating on glass for energy-saving window application. The main highlight is the utilization of Cu, a low-cost material, in-lieu of silver which is widely used in current commercial heat reflecting coating on glass. Color tunable transparent heat reflecting coating was realized through the design of multilayer structure and process optimization. The impact of thermal treatment on the overall performance of sputter deposited TiO2/Cu/TiO2 multilayer thin film on glass substrate is investigated in detail. Significant enhancement of transmittance in the visible range and reflectance in the infra-red (IR) region has been observed after thermal treatment of TiO2/Cu/TiO2 multilayer thin film at 500 °C due to the improvement of crystal quality of TiO2. Highest visible transmittance of 90% and IR reflectance of 85% at a wavelength of 1200 nm are demonstrated for the TiO2/Cu/TiO2 multilayer thin film after annealing at 500 °C. Performance of TiO2/Cu/TiO2 heat reflector coating decreases after thermal treatment at 600 °C. The wear performance of the TiO2/Cu/TiO2 multilayer structure has been evaluated through scratch hardness test. The present work shows promising characteristics of Cu-based THR coating for energy-saving building industry.

  8. Color tunable low cost transparent heat reflector using copper and titanium oxide for energy saving application

    PubMed Central

    Dalapati, Goutam Kumar; Masudy-Panah, Saeid; Chua, Sing Teng; Sharma, Mohit; Wong, Ten It; Tan, Hui Ru; Chi, Dongzhi

    2016-01-01

    Multilayer coating structure comprising a copper (Cu) layer sandwiched between titanium dioxide (TiO2) were demonstrated as a transparent heat reflecting (THR) coating on glass for energy-saving window application. The main highlight is the utilization of Cu, a low-cost material, in-lieu of silver which is widely used in current commercial heat reflecting coating on glass. Color tunable transparent heat reflecting coating was realized through the design of multilayer structure and process optimization. The impact of thermal treatment on the overall performance of sputter deposited TiO2/Cu/TiO2 multilayer thin film on glass substrate is investigated in detail. Significant enhancement of transmittance in the visible range and reflectance in the infra-red (IR) region has been observed after thermal treatment of TiO2/Cu/TiO2 multilayer thin film at 500 °C due to the improvement of crystal quality of TiO2. Highest visible transmittance of 90% and IR reflectance of 85% at a wavelength of 1200 nm are demonstrated for the TiO2/Cu/TiO2 multilayer thin film after annealing at 500 °C. Performance of TiO2/Cu/TiO2 heat reflector coating decreases after thermal treatment at 600 °C. The wear performance of the TiO2/Cu/TiO2 multilayer structure has been evaluated through scratch hardness test. The present work shows promising characteristics of Cu-based THR coating for energy-saving building industry. PMID:26846687

  9. Optimal selection of on-site generation with combined heat andpower applications

    SciTech Connect

    Siddiqui, Afzal S.; Marnay, Chris; Bailey, Owen; HamachiLaCommare, Kristina

    2004-11-30

    While demand for electricity continues to grow, expansion of the traditional electricity supply system, or macrogrid, is constrained and is unlikely to keep pace with the growing thirst western economies have for electricity. Furthermore, no compelling case has been made that perpetual improvement in the overall power quality and reliability (PQR)delivered is technically possible or economically desirable. An alternative path to providing high PQR for sensitive loads would generate close to them in microgrids, such as the Consortium for Electricity Reliability Technology Solutions (CERTS) Microgrid. Distributed generation would alleviate the pressure for endless improvement in macrogrid PQR and might allow the establishment of a sounder economically based level of universal grid service. Energy conversion from available fuels to electricity close to loads can also provide combined heat and power (CHP) opportunities that can significantly improve the economics of small-scale on-site power generation, especially in hot climates when the waste heat serves absorption cycle cooling equipment that displaces expensive on-peak electricity. An optimization model, the Distributed Energy Resources Customer Adoption Model (DER-CAM), developed at Berkeley Lab identifies the energy bill minimizing combination of on-site generation and heat recovery equipment for sites, given their electricity and heat requirements, the tariffs they face, and a menu of available equipment. DER-CAM is used to conduct a systemic energy analysis of a southern California naval base building and demonstrates atypical current economic on-site power opportunity. Results achieve cost reductions of about 15 percent with DER, depending on the tariff.Furthermore, almost all of the energy is provided on-site, indicating that modest cost savings can be achieved when the microgrid is free to select distributed generation and heat recovery equipment in order to minimize its over all costs.

  10. Thermal and cost goal analysis for passive solar heating designs

    SciTech Connect

    Noll, S.A.; Kirschner, C.

    1980-01-01

    Economic methodologies developed over the past several years for the design of residential solar systems have been based on life cycle cost (LCC) minimization. Because of uncertainties involving future economic conditions and the varied decision making processes of home designers, builders, and owners, LCC design approaches are not always appropriate. To deal with some of the constraints that enter the design process, and to narrow the number of variables to those that do not depend on future economic conditions, a simplified thermal and cost goal approach for passive designs is presented. Arithmetic and graphical approaches are presented with examples given for each. Goals discussed include simple payback, solar savings fraction, collection area, maximum allowable construction budget, variable cost goals, and Btu savings.

  11. Design and optimization of geothermal power generation, heating, and cooling

    NASA Astrophysics Data System (ADS)

    Kanoglu, Mehmet

    Most of the world's geothermal power plants have been built in 1970s and 1980s following 1973 oil crisis. Urgency to generate electricity from alternative energy sources and the fact that geothermal energy was essentially free adversely affected careful designs of plants which would maximize their performance for a given geothermal resource. There are, however, tremendous potentials to improve performance of many existing geothermal power plants by retrofitting, optimizing the operating conditions, re-selecting the most appropriate binary fluid in binary plants, and considering cogeneration such as a district heating and/or cooling system or a system to preheat water entering boilers in industrial facilities. In this dissertation, some representative geothermal resources and existing geothermal power plants in Nevada are investigated to show these potentials. Economic analysis of a typical geothermal resource shows that geothermal heating and cooling may generate up to 3 times as much revenue as power generation alone. A district heating/cooling system is designed for its incorporation into an existing 27 MW air-cooled binary geothermal power plant. The system as designed has the capability to meet the entire heating needs of an industrial park as well as 40% of its cooling needs, generating potential revenues of $14,040,000 per year. A study of the power plant shows that evaporative cooling can increase the power output by up to 29% in summer by decreasing the condenser temperature. The power output of the plant can be increased by 2.8 percent by optimizing the maximum pressure in the cycle. Also, replacing the existing working fluid isobutane by butane, R-114, isopentane, and pentane can increase the power output by up to 2.5 percent. Investigation of some well-known geothermal power generation technologies as alternatives to an existing 12.8 MW single-flash geothermal power plant shows that double-flash, binary, and combined flash/binary designs can increase the

  12. Computer simulation and optimal designing of energy-saving technologies of the induction heating of metals

    NASA Astrophysics Data System (ADS)

    Demidovich, V. B.

    2012-12-01

    Advanced energy-saving technologies of induction heating of metals are discussed. The importance of the joint simulation of electromagnetic and temperature fields on induction heating is demonstrated. The package of specialized programs for simulating not only induction heating devices, but also technologies that employ industrial heating has been developed. An intimate connection between optimal design and control of induction heaters is shown.

  13. Optimization and design of pigments for heat-insulating coatings

    NASA Astrophysics Data System (ADS)

    Wang, Guang-Hai; Zhang, Yue

    2010-12-01

    This paper reports that heat insulating property of infrared reflective coatings is obtained through the use of pigments which diffuse near-infrared thermal radiation. Suitable structure and size distribution of pigments would attain maximum diffuse infrared radiation and reduce the pigment volume concentration required. The optimum structure and size range of pigments for reflective infrared coatings are studied by using Kubelka—Munk theory, Mie model and independent scattering approximation. Taking titania particle as the pigment embedded in an inorganic coating, the computational results show that core-shell particles present excellent scattering ability, more so than solid and hollow spherical particles. The optimum radius range of core-shell particles is around 0.3 ~ 1.6 μm. Furthermore, the influence of shell thickness on optical parameters of the coating is also obvious and the optimal thickness of shell is 100-300 nm.

  14. Including sampling and phenotyping costs into the optimization of two stage designs for genomewide association studies.

    PubMed

    Müller, Hans-Helge; Pahl, Roman; Schäfer, Helmut

    2007-12-01

    We propose optimized two-stage designs for genome-wide case-control association studies, using a hypothesis testing paradigm. To save genotyping costs, the complete marker set is genotyped in a sub-sample only (stage I). On stage II, the most promising markers are then genotyped in the remaining sub-sample. In recent publications, two-stage designs were proposed which minimize the overall genotyping costs. To achieve full design optimization, we additionally include sampling costs into both the cost function and the design optimization. The resulting optimal designs differ markedly from those optimized for genotyping costs only (partially optimized designs), and achieve considerable further cost reductions. Compared with partially optimized designs, fully optimized two-stage designs have higher first-stage sample proportion. Furthermore, the increment of the sample size over the one-stage design, which is necessary in two-stage designs in order to compensate for the loss of power due to partial genotyping, is less pronounced for fully optimized two-stage designs. In addition, we address the scenario where the investigator is interested to gain as much information as possible, however is restricted in terms of a budget. In that we develop two-stage designs that maximize the power under a certain cost constraint.

  15. Measured performance results: low-cost solar water heating systems in the San Luis Valley

    SciTech Connect

    Swisher, J.

    1983-01-01

    The measured performance of seven low-cost solar water heating systems in the San Luis Valley of southern Colorado is summarized. During the summer and fall of 1981, SERI monitored a variety of low-cost solar water heating system designs and components. Five systems had site-built collectors, and four included low-cost tank-in-jacket heat exchanger/storage tank components. Two were air-to-water systems. The five liquid-based systems included a drain-down design, a propylene glycol-charged thermosiphon system, and three pumped-glycol systems. The pumped-liquid systems performed the best, with system efficiencies greater than 20% and solar fractions between 40% and 70%. Tjhe air-to-water systems did not perform as well because of leakage in the collectors and heat exchangers. The thermosiphon system performed at lower efficiency because the collector flows were low.

  16. Process Cost Modeling for Multi-Disciplinary Design Optimization

    NASA Technical Reports Server (NTRS)

    Bao, Han P.; Freeman, William (Technical Monitor)

    2002-01-01

    For early design concepts, the conventional approach to cost is normally some kind of parametric weight-based cost model. There is now ample evidence that this approach can be misleading and inaccurate. By the nature of its development, a parametric cost model requires historical data and is valid only if the new design is analogous to those for which the model was derived. Advanced aerospace vehicles have no historical production data and are nowhere near the vehicles of the past. Using an existing weight-based cost model would only lead to errors and distortions of the true production cost. This report outlines the development of a process-based cost model in which the physical elements of the vehicle are costed according to a first-order dynamics model. This theoretical cost model, first advocated by early work at MIT, has been expanded to cover the basic structures of an advanced aerospace vehicle. Elemental costs based on the geometry of the design can be summed up to provide an overall estimation of the total production cost for a design configuration. This capability to directly link any design configuration to realistic cost estimation is a key requirement for high payoff MDO problems. Another important consideration in this report is the handling of part or product complexity. Here the concept of cost modulus is introduced to take into account variability due to different materials, sizes, shapes, precision of fabrication, and equipment requirements. The most important implication of the development of the proposed process-based cost model is that different design configurations can now be quickly related to their cost estimates in a seamless calculation process easily implemented on any spreadsheet tool. In successive sections, the report addresses the issues of cost modeling as follows. First, an introduction is presented to provide the background for the research work. Next, a quick review of cost estimation techniques is made with the intention to

  17. A heat & mass integration approach to reduce capital and operating costs of a distillation configuration

    SciTech Connect

    Madenoor Ramapriya, Gautham; Jiang, Zheyu; Tawarmalani, Mohit; Agrawal, Rakesh

    2015-11-11

    We propose a general method to consolidate distillation columns of a distillation configuration using heat and mass integration. The proposed method encompasses all heat and mass integrations known till date, and includes many more. Each heat and mass integration eliminates a distillation column, a condenser, a reboiler and the heat duty associated with a reboiler. Thus, heat and mass integration can potentially offer significant capital and operating cost benefits. In this talk, we will study the various possible heat and mass integrations in detail, and demonstrate their benefits using case studies. This work will lay out a framework to synthesize an entire new class of useful configurations based on heat and mass integration of distillation columns.

  18. Optimization of Thermoelectric Components for Automobile Waste Heat Recovery Systems

    NASA Astrophysics Data System (ADS)

    Kumar, Sumeet; Heister, Stephen D.; Xu, Xianfan; Salvador, James R.

    2015-10-01

    For a typical spark ignition engine approximately 40% of available thermal energy is lost as hot exhaust gas. To improve fuel economy, researchers are currently evaluating technology which exploits exhaust stream thermal power by use of thermoelectric generators (TEGs) that operate on the basis of the Seebeck effect. A 5% improvement in fuel economy, achieved by use of TEG output power, is a stated objective for light-duty trucks and personal automobiles. System modeling of thermoelectric (TE) components requires solution of coupled thermal and electric fluxes through the n and p-type semiconductor legs, given appropriate thermal boundary conditions at the junctions. Such applications have large thermal gradients along the semiconductor legs, and material properties are highly dependent on spatially varying temperature profiles. In this work, one-dimensional heat flux and temperature variations across thermoelectric legs were solved by using an iterative numerical approach to optimize both TE module and TEG designs. Design traits were investigated by assuming use of skutterudite as a thermoelectric material with potential for automotive applications in which exhaust gas and heat exchanger temperatures typically vary from 100°C to over 600°C. Dependence of leg efficiency, thermal fluxes and electric power generation on leg geometry, fill fractions, electric current, thermal boundary conditions, etc., were studied in detail. Optimum leg geometries were computed for a variety of automotive exhaust conditions.

  19. Limited applicability of cost-effectiveness and cost-benefit analyses for the optimization of radon remedial measures.

    PubMed

    Jiránek, Martin; Rovenská, Katerina

    2010-10-15

    Ways of using different decision-aiding techniques for optimizing and evaluating radon remedial measures have been studied on a large set of data obtained from the remediation of 32 houses that had an original indoor radon level above 1000 Bq/m(3). Detailed information about radon concentrations before and after remediation, type of remedial measures and installation and operation costs were used as the input parameters for a comparison of costs and for determining the efficiencies, for a cost-benefit analysis and a cost-effectiveness analysis, in order to find out whether these criteria and techniques provide sufficient and relevant information for improving and optimizing remediation. Our study confirmed that the installation costs of remediation do not depend on the original indoor radon level, but on the technical state of the building. In addition, the study reveals that the efficiency of remediation does not depend on the installation costs. Cost-benefit analysis and cost-effectiveness analysis lead to the conclusion that remedial measures reducing the indoor radon concentration from values above 1000 Bq/m(3) are always acceptable and reasonable. On the other hand, these techniques can neither help the designer to choose the proper remedial measure nor provide information resulting in improved remediation.

  20. Process industry demand for more efficient, more cost-effective heat exchanger tubing

    SciTech Connect

    Thors, P.

    1987-01-01

    In the future the process industry will see a bigger selection of enhanced heat transfer tubes, one of the reasons being the continued production of special patented technology involved in making them. Here the author mentions only some of the factors that might influence the increased usage of these enhanced tubes. In using more efficient tubing in a heat exchanger the designer has available the options to increase the total heat duty per unit volume, lower operating costs by reducing the mean temperature difference at a given heat duty, save material, or reduce the size and/or pumping power, among others. This can be achieved, for example, by replacing plain tubes with appropriate enhanced tubes in retubing applications, where old heat exchangers need to be upgraded and total efficiency improved. When a new heat exchanger is to be built, it is easier for the designer to include the more efficient tubing to utilize all the benefits of the increased thermal performance.

  1. Investigation of Cost and Energy Optimization of Drinking Water Distribution Systems.

    PubMed

    Cherchi, Carla; Badruzzaman, Mohammad; Gordon, Matthew; Bunn, Simon; Jacangelo, Joseph G

    2015-11-17

    Holistic management of water and energy resources through energy and water quality management systems (EWQMSs) have traditionally aimed at energy cost reduction with limited or no emphasis on energy efficiency or greenhouse gas minimization. This study expanded the existing EWQMS framework and determined the impact of different management strategies for energy cost and energy consumption (e.g., carbon footprint) reduction on system performance at two drinking water utilities in California (United States). The results showed that optimizing for cost led to cost reductions of 4% (Utility B, summer) to 48% (Utility A, winter). The energy optimization strategy was successfully able to find the lowest energy use operation and achieved energy usage reductions of 3% (Utility B, summer) to 10% (Utility A, winter). The findings of this study revealed that there may be a trade-off between cost optimization (dollars) and energy use (kilowatt-hours), particularly in the summer, when optimizing the system for the reduction of energy use to a minimum incurred cost increases of 64% and 184% compared with the cost optimization scenario. Water age simulations through hydraulic modeling did not reveal any adverse effects on the water quality in the distribution system or in tanks from pump schedule optimization targeting either cost or energy minimization.

  2. Cost related sensitivity analysis for optimal operation of a grid-parallel PEM fuel cell power plant

    NASA Astrophysics Data System (ADS)

    El-Sharkh, M. Y.; Tanrioven, M.; Rahman, A.; Alam, M. S.

    Fuel cell power plants (FCPP) as a combined source of heat, power and hydrogen (CHP&H) can be considered as a potential option to supply both thermal and electrical loads. Hydrogen produced from the FCPP can be stored for future use of the FCPP or can be sold for profit. In such a system, tariff rates for purchasing or selling electricity, the fuel cost for the FCPP/thermal load, and hydrogen selling price are the main factors that affect the operational strategy. This paper presents a hybrid evolutionary programming and Hill-Climbing based approach to evaluate the impact of change of the above mentioned cost parameters on the optimal operational strategy of the FCPP. The optimal operational strategy of the FCPP for different tariffs is achieved through the estimation of the following: hourly generated power, the amount of thermal power recovered, power trade with the local grid, and the quantity of hydrogen that can be produced. Results show the importance of optimizing system cost parameters in order to minimize overall operating cost.

  3. Cost/variance optimization for human exposure assessment studies.

    PubMed

    Whitmore, Roy W; Pellizzari, Edo D; Zelon, Harvey S; Michael, Larry C; Quackenboss, James J

    2005-11-01

    The National Human Exposure Assessment Survey (NHEXAS) field study in EPA Region V (one of three NHEXAS field studies) provides extensive exposure data on a representative sample of 249 residents of the Great Lakes states. Concentration data were obtained for both metals and volatile organic compounds (VOCs) from multiple environmental media and from human biomarkers. A variance model for the logarithms of concentration measurements is used to define intraclass correlations between observations within primary sampling units (PSUs) (nominally counties) and within secondary sampling units (SSUs) (nominally Census blocks). A model for the total cost of the study is developed in terms of fixed costs and variable costs per PSU, SSU, and participant. Intraclass correlations are estimated for media and analytes with sufficient sample sizes. We demonstrate how the intraclass correlations and variable cost components can be used to determine the sample allocation that minimizes cost while achieving pre-specified precision constraints for future studies that monitor environmental concentrations and human exposures for metals and VOCs.

  4. Development of low-cost air-to-air heat exchangers. Final report

    SciTech Connect

    Not Available

    1982-11-08

    In summary, comparing the TMG heat exchanger with the well-constructed and high-performance air-to-air heat exchangers assumed for analysis purposes in the LBL studies, the TMG heat exchanger is cost effective for use in low-infiltration houses heated with natural gas, oil and electricity in climates with 4000 or more heating degree (/sup 0/F) days. Experimental and field testing of the final Prototype B air-to-air heat exchanger gave a strong indication that this unit was ready for the market. A Vermont architect ordered 14 units from a pilot production run for a housing project in St. Johnsbury. These units were installed in the late winter of 1981-1982. The units have given excellent service to the point that the architect has considered the use of air-to-air heat exchangers in every subsequent job. Fabrication of the heat exchangers is being done by a small Vermont firm, Echo Fabrications, established primarily to produce air-to-air heat exchangers for the residential and agricultural market. The unit is being marketed under the tradename ECHOCHANGER and is being marketed, distributed and installed by Memphremagog Heat Exchangers, Inc. of Newport, Vermont.

  5. Data of cost-optimality and technical solutions for high energy performance buildings in warm climate

    PubMed Central

    Zacà, Ilaria; D’Agostino, Delia; Maria Congedo, Paolo; Baglivo, Cristina

    2015-01-01

    The data reported in this article refers to input and output information related to the research articles entitled Assessment of cost-optimality and technical solutions in high performance multi-residential buildings in the Mediterranean area by Zacà et al. (Assessment of cost-optimality and technical solutions in high performance multi-residential buildings in the Mediterranean area, in press.) and related to the research article Cost-optimal analysis and technical comparison between standard and high efficient mono residential buildings in a warm climate by Baglivo et al. (Energy, 2015, 10.1016/j.energy.2015.02.062, in press). PMID:26217793

  6. Entransy and exergy analyses for optimizations of heat-work conversion with carnot cycle

    NASA Astrophysics Data System (ADS)

    Han, Chul Ho; Kim, Kyoung Hoon

    2016-06-01

    The concept of entransy has been newly proposed in terms of the analogy between heat and electrical conduction and could be useful in analyzing and optimizing the heat-work conversion systems. This work presents comparative analyses of entransy and exergy for optimizations of heat-work conversion. The work production and heat transfer processes in Carnot cycle system are investigated with the formulations of exergy destruction, entransy loss, work entransy, entransy dissipation, and efficiencies for both cases of dumping and non-dumping of used source fluid. The effects of source and condensation temperatures on the system performance are systematically investigated for optimal condition of producing maximum work or work entransy.

  7. Cost-Based Optimization of a Papermaking Wastewater Regeneration Recycling System

    NASA Astrophysics Data System (ADS)

    Huang, Long; Feng, Xiao; Chu, Khim H.

    2010-11-01

    Wastewater can be regenerated for recycling in an industrial process to reduce freshwater consumption and wastewater discharge. Such an environment friendly approach will also lead to cost savings that accrue due to reduced freshwater usage and wastewater discharge. However, the resulting cost savings are offset to varying degrees by the costs incurred for the regeneration of wastewater for recycling. Therefore, systematic procedures should be used to determine the true economic benefits for any water-using system involving wastewater regeneration recycling. In this paper, a total cost accounting procedure is employed to construct a comprehensive cost model for a paper mill. The resulting cost model is optimized by means of mathematical programming to determine the optimal regeneration flowrate and regeneration efficiency that will yield the minimum total cost.

  8. Coupled heating/forming optimization of knitted reinforced composites

    NASA Astrophysics Data System (ADS)

    Pancrace, Johann

    The feasibility of knitted fabric reinforcement for highly flexible composites has been investigated for the thermoforming process. The composite sheets were made through compression molding before being shaped. We used thermoplastic elastomers as matrices: Thermoplastic Elastomers and Thermoplastic Olefins. The knit reinforcement was provided by jersey knitted fabrics of polyester fibers. We first introduced the fundamentals involved in the study. The manufacturing is presented through compression molding and thermoforming. The latter is a two-step process: IR heating and plug/pressure assisted deformations. For the IR heating phase, several material properties have been characterized: the emissivity of matrices, absorption, reflection and transmission of radiations in the composite structure have been studied. We particularly paid attention to the reflection on the composite surfaces. The non-reflected or useful radiations leading to the heating are quantified and simulated for three emitter-composite configurations. It has been found that the emitter temperatures and the angle of incidence have significant roles in the IR heating phase. Thermal properties such as calorific capacity and thermal conductivity of the composites were also presented. Thermograms were carried out with an IR camera. Equipment and Thermogram acquisitions were both presented. Optimization of emitters was performed for a three emitter system. The objective function method has been illustrated. Regarding mechanical purposes, the characterizations of the matrices, reinforcements and flexible composites have been carried out. The studied loadings were uniaxial traction, pure shear and biaxial inflation. For the uniaxial extension, both the reinforcement and the composite were found highly anisotropic regarding the orientation of the loading toward the coursewise of the fabric. The resulting strains and stresses to rupture are also found anisotropic. However, for pure shear loading we observed

  9. Optimizing Experimental Designs Relative to Costs and Effect Sizes.

    ERIC Educational Resources Information Center

    Headrick, Todd C.; Zumbo, Bruno D.

    A general model is derived for the purpose of efficiently allocating integral numbers of units in multi-level designs given prespecified power levels. The derivation of the model is based on a constrained optimization problem that maximizes a general form of a ratio of expected mean squares subject to a budget constraint. This model provides more…

  10. "Body-In-The-Loop": Optimizing Device Parameters Using Measures of Instantaneous Energetic Cost

    PubMed Central

    Felt, Wyatt; Selinger, Jessica C.; Donelan, J. Maxwell; Remy, C. David

    2015-01-01

    This paper demonstrates methods for the online optimization of assistive robotic devices such as powered prostheses, orthoses and exoskeletons. Our algorithms estimate the value of a physiological objective in real-time (with a body “in-the-loop”) and use this information to identify optimal device parameters. To handle sensor data that are noisy and dynamically delayed, we rely on a combination of dynamic estimation and response surface identification. We evaluated three algorithms (Steady-State Cost Mapping, Instantaneous Cost Mapping, and Instantaneous Cost Gradient Search) with eight healthy human subjects. Steady-State Cost Mapping is an established technique that fits a cubic polynomial to averages of steady-state measures at different parameter settings. The optimal parameter value is determined from the polynomial fit. Using a continuous sweep over a range of parameters and taking into account measurement dynamics, Instantaneous Cost Mapping identifies a cubic polynomial more quickly. Instantaneous Cost Gradient Search uses a similar technique to iteratively approach the optimal parameter value using estimates of the local gradient. To evaluate these methods in a simple and repeatable way, we prescribed step frequency via a metronome and optimized this frequency to minimize metabolic energetic cost. This use of step frequency allows a comparison of our results to established techniques and enables others to replicate our methods. Our results show that all three methods achieve similar accuracy in estimating optimal step frequency. For all methods, the average error between the predicted minima and the subjects’ preferred step frequencies was less than 1% with a standard deviation between 4% and 5%. Using Instantaneous Cost Mapping, we were able to reduce subject walking-time from over an hour to less than 10 minutes. While, for a single parameter, the Instantaneous Cost Gradient Search is not much faster than Steady-State Cost Mapping, the

  11. Improved mine blast algorithm for optimal cost design of water distribution systems

    NASA Astrophysics Data System (ADS)

    Sadollah, Ali; Guen Yoo, Do; Kim, Joong Hoon

    2015-12-01

    The design of water distribution systems is a large class of combinatorial, nonlinear optimization problems with complex constraints such as conservation of mass and energy equations. Since feasible solutions are often extremely complex, traditional optimization techniques are insufficient. Recently, metaheuristic algorithms have been applied to this class of problems because they are highly efficient. In this article, a recently developed optimizer called the mine blast algorithm (MBA) is considered. The MBA is improved and coupled with the hydraulic simulator EPANET to find the optimal cost design for water distribution systems. The performance of the improved mine blast algorithm (IMBA) is demonstrated using the well-known Hanoi, New York tunnels and Balerma benchmark networks. Optimization results obtained using IMBA are compared to those using MBA and other optimizers in terms of their minimum construction costs and convergence rates. For the complex Balerma network, IMBA offers the cheapest network design compared to other optimization algorithms.

  12. Optimized Heat Pipe Backup Cooling System Tested with a Stirling Convertor

    NASA Technical Reports Server (NTRS)

    Schwendeman, Carl L.; Tarau, Calin; Schifer, Nicholas A.; Anderson, William G.; Garner, Scott

    2016-01-01

    In a Stirling Radioisotope Power System (RPS), heat must be continuously removed from the General Purpose Heat Source (GPHS) modules to maintain the modules and surrounding insulation at acceptable temperatures. The Stirling convertor normally provides this cooling. If the Stirling convertor stops in the current system, the insulation is designed to spoil, preventing damage to the GPHS at the cost of an early termination of the mission. An alkali-metal variable conductance heat pipe (VCHP) can be used to passively allow multiple stops and restarts of the Stirling convertor by bypassing the heat during stops. In a previous NASA Small Business Innovation Research (SBIR) Program, Advanced Cooling Technologies, Inc. (ACT) developed a series of sodium VCHPs as backup cooling systems for the Stirling RPS. In 2012, one of these VCHPs was successfully tested at NASA Glenn Research Center with a Stirling convertor as an Advanced Stirling Radioisotope Generator (ASRG) backup cooling system. The prototype; however, was not optimized and did not reflect the final heat rejection path. ACT through further funding has developed a semioptimized prototype with the finalized heat path for testing at Glenn with a Stirling convertor. The semioptimized system features a two-phase radiator and is significantly smaller and lighter than the prior prototype to reflect a higher level of flight readiness. The VCHP is designed to activate and remove heat from the GPHS during stoppage with a small temperature increase from the nominal vapor temperature. This small temperature increase from nominal is low enough to avoid risking standard ASRG operation and spoiling of the multilayer insulation (MLI). The VCHP passively allows the Stirling convertor to be turned off multiple times during a mission with potentially unlimited off durations. Having the ability to turn the Stirling off allows for the Stirling to be reset and reduces vibrations on the platform during sensitive measurements or

  13. A Cost Comparison Framework for Use in Optimizing Ground Water Pump and Treat Systems

    EPA Pesticide Factsheets

    This fact sheet has been prepared to provide a framework for conducting cost comparisons to evaluate whether or not to pursue potential opportunities from an optimization evaluation for improving, replacing, or supplementing the P&T system.

  14. On the optimality equation for average cost Markov control processes with Feller transition probabilities

    NASA Astrophysics Data System (ADS)

    Jaskiewicz, Anna; Nowak, Andrzej S.

    2006-04-01

    We consider Markov control processes with Borel state space and Feller transition probabilities, satisfying some generalized geometric ergodicity conditions. We provide a new theorem on the existence of a solution to the average cost optimality equation.

  15. Integrated energy, economic, and environmental assessment for the optimal solar absorption cooling and heating system

    NASA Astrophysics Data System (ADS)

    Hang, Yin

    Buildings in the United States are responsible for 41% of the primary energy use and 30% of carbon dioxide emissions. Due to mounting concerns about climate change and resource depletion, meeting building heating and cooling demand with renewable energy has attracted increasing attention in the energy system design of green buildings. One of these approaches, the solar absorption cooling and heating (SACH) technology can be a key solution to addressing the energy and environmental challenges. SACH system is an integration of solar thermal heating system and solar thermal driven absorption cooling system. So far, SACH systems still remain at the demonstration and testing stage due to not only its high cost but also complicated system characteristics. This research aims to develop a methodology to evaluate the life cycle energy, economic and environmental performance of SACH systems by high-fidelity simulations validated by experimental data. The developed methodology can be used to assist the system design. In order to achieve this goal, the study includes four objectives as follows: * Objective 1: Develop the evaluation model for the SACH system. The model includes three aspects: energy, economy, and environment from a life cycle point of view. * Objective 2: Validate the energy system model by solar experiments performance data. * Objective 3: Develop a fast and effective multi-objective optimization methodology to find the optimal system configuration which achieves the maximum system benefits on energy, economy and environment. Statistic techniques are explored to reveal the relations between the system key parameters and the three evaluation targets. The Pareto front is generated by solving this multi-objective optimization problem. * Objective 4: Apply the developed assessment methodology to different building types and locations. Furthermore, this study considered the influence of the input uncertainties on the overall system performance. The sensitivity

  16. Antenna optimization and cost consideration for the Solar Power Satellite microwave system

    NASA Technical Reports Server (NTRS)

    Kerwin, E. M.; Suddath, J. H.; Arndt, G. D.

    1981-01-01

    The sizing, criteria, cost analysis, and optimized taper of the Solar Power Satellite (SPS) transmitting antenna are discussed. The sizing parameters considered were a thermal limit of 23 kW/sq m in the antenna, a peak power density of 23 mW/sq cm in the ionosphere, and cost effectiveness. Cost schedules and equations are presented for the SPS, and four antenna tapers are analyzed and compared, including the reference 10 dB Gaussian taper. An even powered quadratic series is formulated to minimize electricity cost and stay within thermal and ionospheric power level limits. The optimized Johnson Space Center taper is found to display the lowest energy costs, 4% below the 10 dB Gaussian, and can deliver 5.69 GW at 45.4 mills/kWh to the grid. Further studies are indicated for the optimal antenna and rectenna sizes

  17. Optimizing Cost Versus Time Shipping of U.S. Navy Retrograde Materiel

    DTIC Science & Technology

    2005-03-01

    bS ATAIqTA-\\PER S C IE NTL4AMj•. NAVAL POSTGRADUATE SCHOOL MONTEREY, CALIFORNIA THESIS OPTIMIZING COST VERSUS TIME SHIPPING OF U.S. NAVY ...SUBTITLE: 5. FUNDING NUMBERS Optimizing Cost Versus Time Shipping of U.S. Navy Retrograde Materiel 6. AUTHOR(S) Colbert, Charles W. 7. PERFORMING...materiel. This thesis models the NAVICP shipping of unserviceable but repairable (retrograde) Navy materiel or Depot Level Repairables (DLRs). It

  18. Ecological optimization of an irreversible quantum Carnot heat engine with spin-1/2 systems

    NASA Astrophysics Data System (ADS)

    Liu, Xiaowei; Chen, Lingen; Wu, Feng; Sun, Fengrui

    2010-02-01

    A model of a quantum heat engine with heat resistance, internal irreversibility and heat leakage and many non-interacting spin-1/2 systems is established in this paper. The quantum heat engine cycle is composed of two isothermal processes and two irreversible adiabatic processes and is referred to as a spin quantum Carnot heat engine. Based on the quantum master equation and the semi-group approach, equations of some important performance parameters, such as power output, efficiency, entropy generation rate and ecological function (a criterion representing the optimal compromise between exergy output rate and exergy loss rate), for the irreversible spin quantum Carnot heat engine are derived. The optimal ecological performance of the heat engine in the classical limit is analyzed with numerical examples. The effects of internal irreversibility and heat leakage on ecological performance are discussed in detail.

  19. Multiple tube structure for heating uniformity and efficiency optimization of microwave ovens

    NASA Astrophysics Data System (ADS)

    Zhou, Rong; Yang, Xiaoqing; Sun, Di; Jia, Guozhu

    2015-02-01

    Microwave heating is widely applied to microwave assisted chemical reactions in modified domestic microwave ovens, however, the potential issues (non-uniformity and low heating efficiency) still exist during the heating process. In this paper, a new heating model of multiple tube structure is proposed and the relevant simulations and experiments of heating water were performed based on the computational platform COMSOL Multi-physics software in order to achieve the better temperature uniformity and heating efficiency. Besides, the influence of the instability of microwave ovens on the heating performances of the optimal heating models was analyzed. The simulation results show that the heating uniformity and efficiency of water in optimal six tube structure increased by 7.1% and 68.5% (30 mL), 9.2% and 61% (60 mL) respectively compared with the optimal single tube structure. Moreover, the heating performances of the optimal heating models do not change obviously, while the working frequency and power change slightly. The simulation results are in good agreement with the experiment data.

  20. A KBE-enabled design framework for cost/weight optimization study of aircraft composite structures

    NASA Astrophysics Data System (ADS)

    Wang, H.; La Rocca, G.; van Tooren, M. J. L.

    2014-10-01

    Traditionally, minimum weight is the objective when optimizing airframe structures. This optimization, however, does not consider the manufacturing cost which actually determines the profit of the airframe manufacturer. To this purpose, a design framework has been developed able to perform cost/weight multi-objective optimization of an aircraft component, including large topology variations of the structural configuration. The key element of the proposed framework is a dedicated knowledge based engineering (KBE) application, called multi-model generator, which enables modelling very different product configurations and variants and extract all data required to feed the weight and cost estimation modules, in a fully automated fashion. The weight estimation method developed in this research work uses Finite Element Analysis to calculate the internal stresses of the structural elements and an analytical composite plate sizing method to determine their minimum required thicknesses. The manufacturing cost estimation module was developed on the basis of a cost model available in literature. The capability of the framework was successfully demonstrated by designing and optimizing the composite structure of a business jet rudder. The study case indicates the design framework is able to find the Pareto optimal set for minimum structural weight and manufacturing costin a very quick way. Based on the Pareto set, the rudder manufacturer is in conditions to conduct both internal trade-off studies between minimum weight and minimum cost solutions, as well as to offer the OEM a full set of optimized options to choose, rather than one feasible design.

  1. Combined Heat and Power System Achieves Millions in Cost Savings at Large University - Case Study

    SciTech Connect

    2013-05-29

    Texas A&M University is operating a high-efficiency combined heat and power (CHP) system at its district energy campus in College Station, Texas. Texas A&M received $10 million in U.S. Department of Energy funding from the American Recovery and Reinvestment Act (ARRA) of 2009 for this project. Private-sector cost share totaled $40 million.

  2. Thermal control of power supplies with electronic packaging techniques. [using low cost heat pipes

    NASA Technical Reports Server (NTRS)

    1977-01-01

    The integration of low-cost commercial heat pipes in the design of a NASA candidate standard modular power supply with a 350 watt output resulted in a 44% weight reduction. Part temperatures were also appreciably reduced, increasing the environmental capability of the unit. A complete 350- watt modular power converter was built and tested to evaluate thermal performance of the redesigned supply.

  3. The environmental cost of subsistence: Optimizing diets to minimize footprints.

    PubMed

    Gephart, Jessica A; Davis, Kyle F; Emery, Kyle A; Leach, Allison M; Galloway, James N; Pace, Michael L

    2016-05-15

    The question of how to minimize monetary cost while meeting basic nutrient requirements (a subsistence diet) was posed by George Stigler in 1945. The problem, known as Stigler's diet problem, was famously solved using the simplex algorithm. Today, we are not only concerned with the monetary cost of food, but also the environmental cost. Efforts to quantify environmental impacts led to the development of footprint (FP) indicators. The environmental footprints of food production span multiple dimensions, including greenhouse gas emissions (carbon footprint), nitrogen release (nitrogen footprint), water use (blue and green water footprint) and land use (land footprint), and a diet minimizing one of these impacts could result in higher impacts in another dimension. In this study based on nutritional and population data for the United States, we identify diets that minimize each of these four footprints subject to nutrient constraints. We then calculate tradeoffs by taking the composition of each footprint's minimum diet and calculating the other three footprints. We find that diets for the minimized footprints tend to be similar for the four footprints, suggesting there are generally synergies, rather than tradeoffs, among low footprint diets. Plant-based food and seafood (fish and other aquatic foods) commonly appear in minimized diets and tend to most efficiently supply macronutrients and micronutrients, respectively. Livestock products rarely appear in minimized diets, suggesting these foods tend to be less efficient from an environmental perspective, even when nutrient content is considered. The results' emphasis on seafood is complicated by the environmental impacts of aquaculture versus capture fisheries, increasing in aquaculture, and shifting compositions of aquaculture feeds. While this analysis does not make specific diet recommendations, our approach demonstrates potential environmental synergies of plant- and seafood-based diets. As a result, this study

  4. Optimizing subsystem test programs. [spacecraft equipment standardization for cost reduction

    NASA Technical Reports Server (NTRS)

    Meyer, W. H.; Pierman, B. C.

    1974-01-01

    The goal of reduction of space system costs is pursued in the areas of standardization of subsystem test requirements as well as overall subsystem test program resource requirements. A number of standard components are being developed by NASA. The rationale for the various environmental tests applicable to future missions and launch vehicles is discussed. The need for and approach to developing standard component specifications is presented. In addition, a method for reduction of test expenditures utilizing indexes of mission effect and hardware history as indicators of test requirements is proposed.

  5. Integration of safety engineering into a cost optimized development program.

    NASA Technical Reports Server (NTRS)

    Ball, L. W.

    1972-01-01

    A six-segment management model is presented, each segment of which represents a major area in a new product development program. The first segment of the model covers integration of specialist engineers into 'systems requirement definition' or the system engineering documentation process. The second covers preparation of five basic types of 'development program plans.' The third segment covers integration of system requirements, scheduling, and funding of specialist engineering activities into 'work breakdown structures,' 'cost accounts,' and 'work packages.' The fourth covers 'requirement communication' by line organizations. The fifth covers 'performance measurement' based on work package data. The sixth covers 'baseline requirements achievement tracking.'

  6. Heliostat field cost reduction by `slope drive' optimization

    NASA Astrophysics Data System (ADS)

    Arbes, Florian; Weinrebe, Gerhard; Wöhrbach, Markus

    2016-05-01

    An algorithm to optimize power tower heliostat fields employing heliostats with so-called slope drives is presented. It is shown that a field using heliostats with the slope drive axes configuration has the same performance as a field with conventional azimuth-elevation tracking heliostats. Even though heliostats with the slope drive configuration have a limited tracking range, field groups of heliostats with different axes or different drives are not needed for different positions in the heliostat field. The impacts of selected parameters on a benchmark power plant (PS10 near Seville, Spain) are analyzed.

  7. Globally Optimal Path Planning with Anisotropic Running Costs

    DTIC Science & Technology

    2013-03-01

    gradient vector differential operator, ∇ = ∑n i=1 ei ∂ ∂zi h triangulation diameter Xh triangulated mesh of diameter h xi a mesh point in Xh Ωh...grid spacing Z set of integers (i, j) integer mesh co-ordinate x(i, j) mesh point in Ωh with integer mesh co-ordinate (i, j) ΩZh set of integer mesh...may not converge to the optimal path as the computational mesh is refined. The final point primarily arises in graph-based methods, and has profound

  8. On the determination of optimal costly measurement strategies for linear stochastic systems.

    NASA Technical Reports Server (NTRS)

    Athans, M.

    1972-01-01

    This paper presents the formulation of a class of optimization problems dealing with selecting, at each instant of time, one measurement provided by one out of many sensors. Each measurement has an associated measurement cost. The basic problem is then to select an optimal measurement policy, during a specified observation time interval, so that a weighted combination of prediction accuracy and accumulated observation cost is optimized. The current analysis is limited to the class of linear stochastic dynamic systems and measurement subsystems. The problem of selecting the optimal measurement strategy can be transformed into a deterministic optimal control problem. It is shown that the optimal measurement policy and the associated matched Kalman-type filter can be precomputed.

  9. Optimal Cooling Load and COP Relationship of a Four-Heat-Reservoir Endoreversible Absorption Refrigeration Cycle

    NASA Astrophysics Data System (ADS)

    Chen, Lingen; Zheng, Tong; Sun, Fengrui; Wu, Chih

    2004-06-01

    On the basis of a four-heat-reservoir endoreversible absorption refrigeration cycle model, another linear heat transfer law [i.e., the heat-flux] is adopted, the fundamental optimal relation between the coefficient of performance (COP) and the cooling load, as well as the maximum cooling load and the corresponding COP of the cycle coupled to constant-temperature heat reservoirs are derived by using finite-time thermodynamics or thermodynamic optimization. The optimal distribution of the heat-transfer surface areas is also obtained. Moreover, the effects of the cycle parameters on the COP and the cooling load of the cycle are studied by detailed numerical examples. The results obtained herein are of importance to the optimal design and performance improvement of an absorption refrigeration cycle.

  10. Cost benefit theory and optimal design of gene regulation functions

    NASA Astrophysics Data System (ADS)

    Kalisky, Tomer; Dekel, Erez; Alon, Uri

    2007-12-01

    Cells respond to the environment by regulating the expression of genes according to environmental signals. The relation between the input signal level and the expression of the gene is called the gene regulation function. It is of interest to understand the shape of a gene regulation function in terms of the environment in which it has evolved and the basic constraints of biological systems. Here we address this by presenting a cost-benefit theory for gene regulation functions that takes into account temporally varying inputs in the environment and stochastic noise in the biological components. We apply this theory to the well-studied lac operon of E. coli. The present theory explains the shape of this regulation function in terms of temporal variation of the input signals, and of minimizing the deleterious effect of cell-cell variability in regulatory protein levels. We also apply the theory to understand the evolutionary tradeoffs in setting the number of regulatory proteins and for selection of feed-forward loops in genetic circuits. The present cost-benefit theory can be used to understand the shape of other gene regulatory functions in terms of environment and noise constraints.

  11. Optimal administrative scale for planning public services: a social cost model applied to Flemish hospital care.

    PubMed

    Blank, Jos L T; van Hulst, Bart

    2015-01-01

    In choosing the scale of public services, such as hospitals, both economic and public administrative considerations play important roles. The scale and the corresponding spatial distribution of public institutions have consequences for social costs, defined as the institutions' operating costs and the users' travel costs (which include the money and time costs). Insight into the relationship between scale and spatial distribution and social costs provides a practical guide for the best possible administrative planning level. This article presents a purely economic model that is suitable for deriving the optimal scale for public services. The model also reveals the corresponding optimal administrative planning level from an economic perspective. We applied this model to hospital care in Flanders for three different types of care. For its application, we examined the social costs of hospital services at different levels of administrative planning. The outcomes show that the social costs of rehabilitation in Flanders with planning at the urban level (38 areas) are 11% higher than those at the provincial level (five provinces). At the regional level (18 areas), the social costs of rehabilitation are virtually equal to those at the provincial level. For radiotherapy, there is a difference of 88% in the social costs between the urban and the provincial level. For general care, there are hardly any cost differences between the three administrative levels. Thus, purely from the perspective of social costs, rehabilitation should preferably be planned at the regional level, general services at the urban level and radiotherapy at the provincial level.

  12. Optimal scheduling of heat-integrated multipurpose plants

    SciTech Connect

    Papageorgiou, L.G.; Shah, N.; Pantelides, C.C. . Centre for Process Systems Engineering)

    1994-12-01

    A systematic mathematical framework for scheduling the operation of multipurpose batch/semicontinuous plants involving heat-integrated unit operations is presented. The approach advocated takes direct account of the trade-offs between maximal exploitation of heat integration and other scheduling objectives and constraints. Both direct and indirect heat integration are considered. In the former case, heat transfer takes place directly between the fluids undergoing processing in the heat-integrated unit operations, and therefore a degree of time overlap of these operations must be ensured. It is shown that this involves only relatively minor modifications to existing detailed scheduling formulations. Indirect heat integration utilizes a heat transfer medium (HTM) which acts as a mechanism both for transferring heat from one operation to another and for storing energy over time. This provides a degree of decoupling with respect to the timing of the operations involved. The mathematical formulation presented in this paper is based on a detailed characterization of the variation of the mass and energy holdups of HTM over time. In particular, it takes account of the limitations on energy storage due to heat loss to the environment. A modified branch-and-bound procedure is proposed for the solution of the resulting nonconvex mixed integer nonlinear programming problem.

  13. The shutdown reactor: Optimizing spent fuel storage cost

    SciTech Connect

    Pennington, C.W.

    1995-12-31

    Several studies have indicated that the most prudent way to store fuel at a shutdown reactor site safely and economically is through the use of a dry storage facility licensed under 10CFR72. While such storage is certainly safe, is it true that the dry ISFSI represents the safest and most economical approach for the utility? While no one is really able to answer that question definitely, as yet, Holtec has studied this issue for some time and believes that both an economic and safety case can be made for an optimization strategy that calls for the use of both wet and dry ISFSI storage of spent fuel at some plants. For the sake of brevity, this paper summarizes some of Holtec`s findings with respect to the economics of maintaining some fuel in wet storage at a shutdown reactor. The safety issue, or more importantly the perception of safety of spent fuel in wet storage, still varies too much with the eye of the beholder, and until a more rigorous presentation of safety analyses can be made in a regulatory setting, it is not practically useful to argue about how many angels can sit on the head of a safety-related pin. Holtec is prepared to present such analyses, but this does not appear to be the proper venue. Thus, this paper simply looks at certain economic elements of a wet ISFSI at a shutdown reactor to make a prima facie case that wet storage has some attractiveness at a shutdown reactor and should not be rejected out of hand. Indeed, an optimization study at certain plants may well show the economic vitality of keeping some fuel in the pool and converting the NRC licensing coverage from 10CFR50 to 10CFR72. If the economics look attractive, then the safety issue may be confronted with a compelling interest.

  14. Optimal control and cost-effective analysis of malaria/visceral leishmaniasis co-infection

    PubMed Central

    Agusto, Folashade B.; ELmojtaba, Ibrahim M.

    2017-01-01

    In this paper, a deterministic model involving the transmission dynamics of malaria/visceral leishmaniasis co-infection is presented and studied. Optimal control theory is then applied to investigate the optimal strategies for curtailing the spread of the diseases using the use of personal protection, indoor residual spraying and culling of infected reservoirs as the system control variables. Various combination strategies were examined so as to investigate the impact of the controls on the spread of the disease. And we investigated the most cost-effective strategy of all the control strategies using three approaches, the infection averted ratio (IAR), the average cost-effectiveness ratio (ACER) and incremental cost-effectiveness ratio (ICER). Our results show that the implementation of the strategy combining all the time dependent control variables is the most cost-effective control strategy. This result is further emphasized by using the results obtained from the cost objective functional, the ACER, and the ICER. PMID:28166308

  15. Multi-objective optimization approach for cost management during product design at the conceptual phase

    NASA Astrophysics Data System (ADS)

    Durga Prasad, K. G.; Venkata Subbaiah, K.; Narayana Rao, K.

    2014-03-01

    The effective cost management during the conceptual design phase of a product is essential to develop a product with minimum cost and desired quality. The integration of the methodologies of quality function deployment (QFD), value engineering (VE) and target costing (TC) could be applied to the continuous improvement of any product during product development. To optimize customer satisfaction and total cost of a product, a mathematical model is established in this paper. This model integrates QFD, VE and TC under multi-objective optimization frame work. A case study on domestic refrigerator is presented to show the performance of the proposed model. Goal programming is adopted to attain the goals of maximum customer satisfaction and minimum cost of the product.

  16. Low-cost light-weight thin material solar heating system

    NASA Astrophysics Data System (ADS)

    Wilhelm, W. G.

    1985-03-01

    Presented in this paper are innovative concepts to substantially reduce the cost of residential solar application. They were based on a research and development approach that establishes cost goals which if successfully met can insure high marketability. Included in this cost goal oriented approach is the additional need to address aesthetics and performance. With such constraints established, designs were initialized, tested, and iterated towards appropriate solutions. These solutions are based on methods for reducing the material intensity of the products, improving the simplicity for ease of production, and reducing the cost of installation. Such a development approach has yielded past proof of concept designs in the solar collector and in the other components that constitute a total solar heating system.

  17. Life Cycle Cost Analyses of U.S. Air Force Heating Plants

    DTIC Science & Technology

    1989-08-01

    1989. 31 ORNL/TM- 11146 internal Distribution 1. D. W. Burton 17. V. K. Wilkinson 2. E. C. Fox 18-20. J. M. Young 3 -7. F. P. Griffin 21. Central Research...required for the heating plant operation are assumed to follow the standard "bathtub" reliability curve as shown in Fig. 3 . The first three years of...ORNL/TM- 11146 NOAK RIDGE ~NATIONAL N LABORATORY Life-Cycle Cost Analyses of U.S.Air Force Heating Plants V. K. Wilkinson DTI * ~DI LECT A’roreve-3f

  18. A system-level cost-of-energy wind farm layout optimization with landowner modeling

    SciTech Connect

    Chen, Le; MacDonald, Erin

    2013-10-01

    This work applies an enhanced levelized wind farm cost model, including landowner remittance fees, to determine optimal turbine placements under three landowner participation scenarios and two land-plot shapes. Instead of assuming a continuous piece of land is available for the wind farm construction, as in most layout optimizations, the problem formulation represents landowner participation scenarios as a binary string variable, along with the number of turbines. The cost parameters and model are a combination of models from the National Renewable Energy Laboratory (NREL), Lawrence Berkeley National Laboratory, and Windustiy. The system-level cost-of-energy (COE) optimization model is also tested under two land-plot shapes: equally-sized square land plots and unequal rectangle land plots. The optimal COEs results are compared to actual COE data and found to be realistic. The results show that landowner remittances account for approximately 10% of farm operating costs across all cases. Irregular land-plot shapes are easily handled by the model. We find that larger land plots do not necessarily receive higher remittance fees. The model can help site developers identify the most crucial land plots for project success and the optimal positions of turbines, with realistic estimates of costs and profitability. (C) 2013 Elsevier Ltd. All rights reserved.

  19. Reconstruction of the unknown optimization cost functions from experimental recordings during static multi-finger prehension.

    PubMed

    Niu, Xun; Terekhov, Alexander V; Latash, Mark L; Zatsiorsky, Vladimir M

    2012-04-01

    The goal of the research is to reconstruct the unknown cost (objective) function(s) presumably used by the neural controller for sharing the total force among individual fingers in multifinger prehension. The cost function was determined from experimental data by applying the recently developed Analytical Inverse Optimization (ANIO) method (Terekhov et al. 2010). The core of the ANIO method is the Theorem of Uniqueness that specifies conditions for unique (with some restrictions) estimation of the objective functions. In the experiment, subjects (n = 8) grasped an instrumented handle and maintained it at rest in the air with various external torques, loads, and target grasping forces applied to the object. The experimental data recorded from 80 trials showed a tendency to lie on a 2-dimensional hyperplane in the 4-dimensional finger-force space. Because the constraints in each trial were different, such a propensity is a manifestation of a neural mechanism (not the task mechanics). In agreement with the Lagrange principle for the inverse optimization, the plane of experimental observations was close to the plane resulting from the direct optimization. The latter plane was determined using the ANIO method. The unknown cost function was reconstructed successfully for each performer, as well as for the group data. The cost functions were found to be quadratic with nonzero linear terms. The cost functions obtained with the ANIO method yielded more accurate results than other optimization methods. The ANIO method has an evident potential for addressing the problem of optimization in motor control.

  20. Thermodynamic analysis and optimization of air-cooled heat exchangers

    NASA Astrophysics Data System (ADS)

    Salimpour, Mohammad Reza; Bahrami, Zabihollah

    2011-01-01

    In the present study, a thermodynamic second-law analysis was performed to investigate the effects of different geometry and flow parameters on the air-cooled heat exchanger performance. For this purpose, the entropy generation due to heat transfer and pressure loss of internal and external flows of the air-cooled heat exchanger was calculated; and it was observed that the total entropy generation has a minimum at special tube-side Reynolds number. Also, it was seen that the increasing of the tube-side Reynolds number resulted in the rise of the irreversibility of the air-cooled heat exchanger. The results also showed when air-side Reynolds number decreased, the entropy generation rate of the external flow reduced. Finally, based on the computed results, a new correlation was developed to predict the optimum Reynolds number of the tube-side fluid flow.

  1. Optimized Heat Interception for Cryogen Tank Support Structure

    NASA Technical Reports Server (NTRS)

    Canavan, E. R.; Miller, F. K.

    2007-01-01

    We consider means for using the cooling available in boil-off gas to intercept heat conducted through the support structure of a cryogen tank. A one-dimensional model of the structure coupled to a gas stream gives an analytical expression for heat leak in terms of flow rate for temperature independent properties and laminar flow. A numerical model has been developed for heat transfer on a thin cylindrical tube with an attached vent line. The model is used to determine the vent path layout that will minimize heat flow into the cryogen tank. The results are useful for a number of applications, but the one of interest in this study is the minimization of the boil-off in large cryopropellant tanks in low Earth and low lunar orbit.

  2. Utility reduces fuel cost with heat recovery, industrial byproduct fuel, cogeneration

    SciTech Connect

    Holland, R.J.

    1982-02-01

    A 50-MW North Dakota power plant is refurbished to recover major waste-heat sources. Use of agricultural byproduct fuel and cogeneration also helps to cut future costs. The plant is saving on fuel costs by burning 150-200 tons/day of sunflower seed hulls from a local processing plant. The hulls are pulverized and mixed with the primary fuel, North Dakota lignite. At the same time, the processing plant that supplies the sunflower hulls buys steam from the power plant, thus giving the utility some of the economic benefits of cogeneration.

  3. Residential heating costs: a comparison of geothermal, solar and conventional resources

    SciTech Connect

    Bloomster, C.H.; Garrett-Price, B.A.; Fassbender, L.L.

    1980-08-01

    The costs of residential heating throughout the United States using conventional, solar, and geothermal energy were determined under current and projected conditions. These costs are very sensitive to location - being dependent on the local prices of conventional energy supplies, local solar insolation, cimate, and the proximity and temperature of potential geothermal resources. The sharp price increases in imported fuels during 1979 and the planned decontrol of domestic oil and natural gas prices have set the stage for geothermal and solar market penetration in the 1980's.

  4. Investigation of using a power function as a cost function in inverse planning optimization.

    PubMed

    Xia, Ping; Yu, Naichang; Xing, Lei; Sun, Xuepeng; Verhey, Lynn J

    2005-04-01

    The purpose of this paper is to investigate the use of a power function as a cost function in inverse planning optimization. The cost function for each structure is implemented as an exponential power function of the deviation between the resultant dose and prescribed or constrained dose. The total cost function for all structures is a summation of the cost function of every structure. When the exponents of all terms in the cost function are set to 2, the cost function becomes a classical quadratic cost function. An independent optimization module was developed and interfaced with a research treatment planning system from the University of North Carolina for dose calculation and display of results. Three clinical cases were tested for this study with various exponents set for tumor targets and sensitive structures. Treatment plans with these exponent settings were compared, using dose volume histograms. The results of our study demonstrated that using an exponent higher than 2 in the cost function for the target achieved better dose homogeneity than using an exponent of 2. An exponent higher than 2 for serial sensitive structures can effectively reduce the maximum dose. Varying the exponent from 2 to 4 resulted in the most effective changes in dose volume histograms while the change from 4 to 8 is less drastic, indicating a situation of saturation. In conclusion, using a power function with exponent greater than 2 as a cost function can effectively achieve homogeneous dose inside the target and/or minimize maximum dose to the critical structures.

  5. The study on optimal operation of compound heat-pump system

    NASA Astrophysics Data System (ADS)

    Shin, Kwan-Woo; Kim, Ilhyun; Kim, Yong-Tae

    2007-12-01

    Heat-pump system has a special feature that provides heating operation in winter season and cooling operation in summer season with a single system. It also has a merit that absorbs and makes use of wastewater heat, terrestrial heat, and heat energy from the air. Because heat-pump system uses midnight electric power, it decreases power peak load and is very economical as a result. By using the property that energy source is converted to low temperature when losing the heat, high temperature energy source is used to provide heating water and low temperature energy source is used to provide cooling water simultaneously in summer season. This study made up a heat-pump system with 4 air heat sources and a water heat source and implemented the optimal operation algorithm that works with numbers of heat pumps to operate them efficiently. With the heat-pump system, we applied it to cooling and heating operation in summer season and in winter season operation mode in a real building.

  6. Heating Water with Solar Energy Costs Less at the Phoenix Federal Correctional Institution

    SciTech Connect

    Not Available

    2004-09-01

    A large solar thermal system installed at the Phoenix Federal Correctional Institution (FCI) in 1998 heats water for the prison and costs less than buying electricity to heat that water. This renewable energy system provides 70% of the facility's annual hot water needs. The Federal Bureau of Prisons did not incur the up-front cost of this system because it was financed through an Energy Savings Performance Contract (ESPC). The ESPC payments are 10% less than the energy savings so that the prison saves an average of$6,700 per year, providing an immediate payback. The solar hot water system produces up to 50,000 gallons of hot water daily, enough to meet the needs of 1,250 inmates and staff who use the kitchen, shower, and laundry facilities.

  7. Heating Water with Solar Energy Costs Less at the Phoenix Federal Correctional Institution

    SciTech Connect

    2004-09-01

    A large solar thermal system installed at the Phoenix Federal Correctional Institution (FCI) in 1998 heats water for the prison and costs less than buying electricity to heat that water. This renewable energy system provides 70% of the facility's annual hot water needs. The Federal Bureau of Prisons did not incur the up-front cost of this system because it was financed through an Energy Savings Performance Contract (ESPC). The ESPC payments are 10% less than the energy savings so that the prison saves an average of $6,700 per year, providing an immediate payback. The solar hot water system produces up to 50,000 gallons of hot water daily, enough to meet the needs of 1,250 inmates and staff who use the kitchen, shower, and laundry facilities. This publication details specifications of the parabolic trough solar system and highlights 5 years of measured performance data.

  8. Multi-objective optimization of electronics heat sinks cooled by natural convection

    NASA Astrophysics Data System (ADS)

    Lampio, K.; Karvinen, R.

    2016-09-01

    Fins and fin arrays with constant temperature at the fin base have known solutions for natural convection. However, in practical applications, no simple solution exists for maximum temperature of heat sink with many heat dissipating components located at the base plate. A calculation model is introduced here to solve this practical problem without time consuming CFD modelling of fluid flow and heat transfer. Solutions with the new model are compared with some simple analytical and CFD solutions to prove that the results are accurate enough for practical applications. Seminal here is that results are obtained many orders of magnitude faster than with CFD. This much shorter calculation time scale makes the model well suited for multi-objective optimization in, e.g., simultaneous minimization of heat sink maximum temperature, size, and mass. An optimization case is presented in which heat sink mass and size are significantly reduced over those of the original reference heat sink.

  9. Adjoint-based constrained topology optimization for viscous flows, including heat transfer

    NASA Astrophysics Data System (ADS)

    Kontoleontos, E. A.; Papoutsis-Kiachagias, E. M.; Zymaris, A. S.; Papadimitriou, D. I.; Giannakoglou, K. C.

    2013-08-01

    In fluid mechanics, topology optimization is used for designing flow passages, connecting predefined inlets and outlets, with optimal performance based on selected criteria. In this article, the continuous adjoint approach to topology optimization in incompressible ducted flows with heat transfer is presented. A variable porosity field, to be determined during the optimization, is the means to define the optimal topology. The objective functions take into account viscous losses and the amount of heat transfer. Turbulent flows are handled using the Spalart-Allmaras model and the proposed adjoint is exact, i.e. the adjoint to the turbulence model equation is formulated and solved, too. This is an important novelty in this article which extends the porosity-based method to account for heat transfer flow problems in turbulent flows. In problems such as the design of manifolds, constraints on the outlet flow direction, rates and mean outlet temperatures are imposed.

  10. Vertical and lateral flight optimization algorithm and missed approach cost calculation

    NASA Astrophysics Data System (ADS)

    Murrieta Mendoza, Alejandro

    Flight trajectory optimization is being looked as a way of reducing flight costs, fuel burned and emissions generated by the fuel consumption. The objective of this work is to find the optimal trajectory between two points. To find the optimal trajectory, the parameters of weight, cost index, initial coordinates, and meteorological conditions along the route are provided to the algorithm. This algorithm finds the trajectory where the global cost is the most economical. The global cost is a compromise between fuel burned and flight time, this is determined using a cost index that assigns a cost in terms of fuel to the flight time. The optimization is achieved by calculating a candidate optimal cruise trajectory profile from all the combinations available in the aircraft performance database. With this cruise candidate profile, more cruises profiles are calculated taken into account the climb and descend costs. During cruise, step climbs are evaluated to optimize the trajectory. The different trajectories are compared and the most economical one is defined as the optimal vertical navigation profile. From the optimal vertical navigation profile, different lateral routes are tested. Taking advantage of the meteorological influence, the algorithm looks for the lateral navigation trajectory where the global cost is the most economical. That route is then selected as the optimal lateral navigation profile. The meteorological data was obtained from environment Canada. The new way of obtaining data from the grid from environment Canada proposed in this work resulted in an important computation time reduction compared against other methods such as bilinear interpolation. The algorithm developed here was evaluated in two different aircraft: the Lockheed L-1011 and the Sukhoi Russian regional jet. The algorithm was developed in MATLAB, and the validation was performed using Flight-Sim by Presagis and the FMS CMA-9000 by CMC Electronics -- Esterline. At the end of this work a

  11. Optimization of operating parameters of endothermic generators with electric heating of retort

    NASA Astrophysics Data System (ADS)

    Dubinin, A. M.; Fink, A. V.; Kagarmanov, G. R.

    2009-07-01

    Equations of heat and gas balance of endothermic generator at air conversion of methane are used for optimizing the parameters with respect to maximum yield of hydrogen and carbon oxide at minimum consumption of electric energy for heating the retort with catalyst.

  12. Optimization of a solar-driven irreversible Carnot heat engine at maximum power output

    SciTech Connect

    Goektun, S.

    1997-08-01

    By employing the energetic optimization technique, the optimum performance of an irreversible Carnot heat engine system driven by a corrugated sheet collector is investigated at maximum power output. The maximum overall efficiency of the system is expressed in terms of the operating parameter of the collector and the cycle-irreversibility parameter of the heat engine.

  13. Optimization of the thermodynamic cycles of a collective heating power station

    NASA Astrophysics Data System (ADS)

    Hausmann, G.

    The optimization of the centralized heating system of a city was studied. Modifications of the heating circuit increase the electric power characteristic from 0.20 to 0.37. A program for the calculation of the changes in the thermodynamic cyclic due to these modifications is presented.

  14. Optimization of the heating surface shape in the contact melting problem

    NASA Technical Reports Server (NTRS)

    Fomin, Sergei A.; Cheng, Shangmo

    1991-01-01

    The theoretical analysis of contact melting by the migrating heat source with an arbitrary shaped isothermal heating surface is presented. After the substantiated simplification, the governing equations are transformed to the convenient equations for engineering calculations relationships. Analytical solutions are used for numerical prediction of optimal shape of the heating surface. The problem is investigated for the constant and for temperature dependent physical properties of the melt.

  15. MULTI-SCALE MODELING AND APPROXIMATION ASSISTED OPTIMIZATION OF BARE TUBE HEAT EXCHANGERS

    SciTech Connect

    Bacellar, Daniel; Ling, Jiazhen; Aute, Vikrant; Radermacher, Reinhard; Abdelaziz, Omar

    2014-01-01

    Air-to-refrigerant heat exchangers are very common in air-conditioning, heat pump and refrigeration applications. In these heat exchangers, there is a great benefit in terms of size, weight, refrigerant charge and heat transfer coefficient, by moving from conventional channel sizes (~ 9mm) to smaller channel sizes (< 5mm). This work investigates new designs for air-to-refrigerant heat exchangers with tube outer diameter ranging from 0.5 to 2.0mm. The goal of this research is to develop and optimize the design of these heat exchangers and compare their performance with existing state of the art designs. The air-side performance of various tube bundle configurations are analyzed using a Parallel Parameterized CFD (PPCFD) technique. PPCFD allows for fast-parametric CFD analyses of various geometries with topology change. Approximation techniques drastically reduce the number of CFD evaluations required during optimization. Maximum Entropy Design method is used for sampling and Kriging method is used for metamodeling. Metamodels are developed for the air-side heat transfer coefficients and pressure drop as a function of tube-bundle dimensions and air velocity. The metamodels are then integrated with an air-to-refrigerant heat exchanger design code. This integration allows a multi-scale analysis of air-side performance heat exchangers including air-to-refrigerant heat transfer and phase change. Overall optimization is carried out using a multi-objective genetic algorithm. The optimal designs found can exhibit 50 percent size reduction, 75 percent decrease in air side pressure drop and doubled air heat transfer coefficients compared to a high performance compact micro channel heat exchanger with same capacity and flow rates.

  16. Item Unique Identification Capability Expansion: Established Process Analysis, Cost Benefit Analysis, and Optimal Marking Procedures

    DTIC Science & Technology

    2014-12-01

    manufacturer MIL-STD military standard Mm millimeter NCCA Naval Center for Cost Analysis Nd neodymium -doped NPS Naval Postgraduate School NSLC...involves the bonding of a material to the substrate surface using the heat generated by a neodymium -doped (Nd) YAG laser or equivalent. The materials used

  17. Optimization for performance-based design under seismic demands, including social costs

    NASA Astrophysics Data System (ADS)

    Möller, Oscar; Foschi, Ricardo O.; Ascheri, Juan P.; Rubinstein, Marcelo; Grossman, Sergio

    2015-06-01

    Performance-based design in earthquake engineering is a structural optimization problem that has, as the objective, the determination of design parameters for the minimization of total costs, while at the same time satisfying minimum reliability levels for the specified performance criteria. Total costs include those for construction and structural damage repairs, those associated with non-structural components and the social costs of economic losses, injuries and fatalities. This paper presents a general framework to approach this problem, using a numerical optimization strategy and incorporating the use of neural networks for the evaluation of dynamic responses and the reliability levels achieved for a given set of design parameters. The strategy is applied to an example of a three-story office building. The results show the importance of considering the social costs, and the optimum failure probabilities when minimum reliability constraints are not taken into account.

  18. Cost and Performance Optimization of the NLC Bunch Compressor Systems(LCC-0021)

    SciTech Connect

    Emma, P

    2004-04-14

    The performance requirements and design options of the NLC bunch compressor systems are reviewed in the interest of producing a more cost-effective design. The cost and performance of the systems are optimized by trading rf costs with compressor beamline costs. Reasonable limits on the critical beam parameters are used to weigh the final result such that the performance is not compromised. In the process, the sensitivity of the system to injected phase errors is studied and minimized in a simple, calculable way. The system is tested with full longitudinal tracking and some important tolerances are examined. Finally, the impacts of a central injector complex on the compressor design are explored and a few versions are presented. The result is a clear procedure that can be used to generate an optimized, stable compressor design once the final character of the injector complex has been decided.

  19. Metabolic costs of heat solicitation calls in relation to thermal need in embryos of American white pelicans.

    PubMed

    Abraham; Evans

    1999-04-01

    Chilled embryos of pelicans, Pelecanus erythrorhynchos, begin to vocally solicit parental heat at the pipped-egg stage. Honest signalling models predict that if vocal heat solicitation is a true reflection of need, then solicitation should be costly and costs should increase with the embryo's need for warmth. Using open-flow respirometry, we measured the metabolic costs associated with vocal heat solicitation by exposing embryos to either a decreasing or increasing series of body temperatures, ranging from 25 to 37.8 degrees C. We measured baseline costs (stable temperature, embryo silent) and costs associated with cold-induced calling at each temperature. At natural incubation temperature (37.8 degrees C), call rates and costs associated with calling were negligible, as was thermal need. Metabolic costs relative to baseline costs and costs per call increased with thermal need as body temperature declined. Absolute metabolic costs increased between 37.8 and 35 degrees C, then remained stable down to 25 degrees C. Call rates increased as embryos were chilled within the range of temperatures most frequently experienced in nature (35-37.8 degrees C), then decreased significantly for all lower temperatures, probably owing to reduced overall metabolic rate at lower temperatures (25-37.8 degrees C). The results generally support the honest signalling prediction that vocal heat solicitation is metabolically costly, and that costs increase with need. Copyright 1999 The Association for the Study of Animal Behaviour.

  20. Evidence for Composite Cost Functions in Arm Movement Planning: An Inverse Optimal Control Approach

    PubMed Central

    Berret, Bastien; Chiovetto, Enrico; Nori, Francesco; Pozzo, Thierry

    2011-01-01

    An important issue in motor control is understanding the basic principles underlying the accomplishment of natural movements. According to optimal control theory, the problem can be stated in these terms: what cost function do we optimize to coordinate the many more degrees of freedom than necessary to fulfill a specific motor goal? This question has not received a final answer yet, since what is optimized partly depends on the requirements of the task. Many cost functions were proposed in the past, and most of them were found to be in agreement with experimental data. Therefore, the actual principles on which the brain relies to achieve a certain motor behavior are still unclear. Existing results might suggest that movements are not the results of the minimization of single but rather of composite cost functions. In order to better clarify this last point, we consider an innovative experimental paradigm characterized by arm reaching with target redundancy. Within this framework, we make use of an inverse optimal control technique to automatically infer the (combination of) optimality criteria that best fit the experimental data. Results show that the subjects exhibited a consistent behavior during each experimental condition, even though the target point was not prescribed in advance. Inverse and direct optimal control together reveal that the average arm trajectories were best replicated when optimizing the combination of two cost functions, nominally a mix between the absolute work of torques and the integrated squared joint acceleration. Our results thus support the cost combination hypothesis and demonstrate that the recorded movements were closely linked to the combination of two complementary functions related to mechanical energy expenditure and joint-level smoothness. PMID:22022242

  1. Evaluation of Externality Costs in Life-Cycle Optimization of Municipal Solid Waste Management Systems.

    PubMed

    Martinez-Sanchez, Veronica; Levis, James W; Damgaard, Anders; DeCarolis, Joseph F; Barlaz, Morton A; Astrup, Thomas F

    2017-03-21

    The development of sustainable solid waste management (SWM) systems requires consideration of both economic and environmental impacts. Societal life-cycle costing (S-LCC) provides a quantitative framework to estimate both economic and environmental impacts, by including "budget costs" and "externality costs". Budget costs include market goods and services (economic impact), whereas externality costs include effects outside the economic system (e.g., environmental impact). This study demonstrates the applicability of S-LCC to SWM life-cycle optimization through a case study based on an average suburban U.S. county of 500 000 people generating 320 000 Mg of waste annually. Estimated externality costs are based on emissions of CO2, CH4, N2O, PM2.5, PM10, NOx, SO2, VOC, CO, NH3, Hg, Pb, Cd, Cr (VI), Ni, As, and dioxins. The results indicate that incorporating S-LCC into optimized SWM strategy development encourages the use of a mixed waste material recovery facility with residues going to incineration, and separated organics to anaerobic digestion. Results are sensitive to waste composition, energy mix and recycling rates. Most of the externality costs stem from SO2, NOx, PM2.5, CH4, fossil CO2, and NH3 emissions. S-LCC proved to be a valuable tool for policy analysis, but additional data on key externality costs such as organic compounds emissions to water would improve future analyses.

  2. Development of a Low Cost Heat Pump Water Heater - Second Prototype

    SciTech Connect

    Mei, V. C.; Craddick, William G

    2007-09-01

    Since the 1980s various attempts have been made to apply the efficiency of heat pumps to water heating. The products generated in the 80s and 90s were not successful, due in part to a lack of reliability and difficulties with installation and servicing. At the turn of the century, EnvironMaster International (EMI) produced a heat pump water heater (HPWH) based on a design developed by Arthur D. Little (ADL), with subsequent developmental assistance from Oak Ridge National Laboratory (ORNL) and ADL. This design was a drop-in replacement for conventional electric water heaters. In field and durability testing conducted by ORNL, it proved to be reliable and saved on average more than 50% of the energy used by the best conventional electric water heater. However, the retail price set by EMI was very high, and it failed in the market. ORNL was tasked to examine commercially available HPWH product technology and manufacturing processes for cost saving opportunities. Several cost saving opportunities were found. To verify the feasibility of these cost saving measures, ORNL completed a conceptual design for an HPWH based on an immersed condenser coil that could be directly inserted into a standard water tank through a sleeve affixed to one of the standard penetrations at the top of the tank. After some experimentation, a prototype unit was built with a double-wall coil inserted into the tank. When tested it achieved an energy factor (EF) of 2.12 to 2.2 using DOE-specified test procedures. A.O. Smith contacted ORNL in May 2006 expressing their interest in the ORNL design. The prototype unit was shipped to A.O. Smith to be tested in their laboratory. After they completed their test, ORNL analyzed the raw test data provided by A.O. Smith and calculated the EF to be approximately 1.92. The electric resistance heating elements of a conventional electric water heater are typically retained in a heat pump water heater to provide auxiliary heating capacity in periods of high

  3. Admitting the Inadmissible: Adjoint Formulation for Incomplete Cost Functionals in Aerodynamic Optimization

    NASA Technical Reports Server (NTRS)

    Arian, Eyal; Salas, Manuel D.

    1997-01-01

    We derive the adjoint equations for problems in aerodynamic optimization which are improperly considered as "inadmissible." For example, a cost functional which depends on the density, rather than on the pressure, is considered "inadmissible" for an optimization problem governed by the Euler equations. We show that for such problems additional terms should be included in the Lagrangian functional when deriving the adjoint equations. These terms are obtained from the restriction of the interior PDE to the control surface. Demonstrations of the explicit derivation of the adjoint equations for "inadmissible" cost functionals are given for the potential, Euler, and Navier-Stokes equations.

  4. Study, optimization, and design of a laser heat engine

    NASA Technical Reports Server (NTRS)

    1978-01-01

    Laser heat engine concepts, proposed for satellite applications, were analyzed to determine which engine concepts best meet the requirements of high efficiency (50 percent or better) continuous operation in space. The best laser heat engine for a near-term experimental demonstration, selected on the basis of high overall operating efficiency, high power-to-weight characteristics, and availability of the required technology, is an Otto/Diesel cycle piston engine using a diamond window to admit CO2 laser radiation. The technology with the greatest promise of scaling to megawatt power levels in the long term is the energy exchanger/gas turbine combination.

  5. Cost-Benefit Analysis for Optimization of Risk Protection Under Budget Constraints.

    PubMed

    Špačková, Olga; Straub, Daniel

    2015-05-01

    Cost-benefit analysis (CBA) is commonly applied as a tool for deciding on risk protection. With CBA, one can identify risk mitigation strategies that lead to an optimal tradeoff between the costs of the mitigation measures and the achieved risk reduction. In practical applications of CBA, the strategies are typically evaluated through efficiency indicators such as the benefit-cost ratio (BCR) and the marginal cost (MC) criterion. In many of these applications, the BCR is not consistently defined, which, as we demonstrate in this article, can lead to the identification of suboptimal solutions. This is of particular relevance when the overall budget for risk reduction measures is limited and an optimal allocation of resources among different subsystems is necessary. We show that this problem can be formulated as a hierarchical decision problem, where the general rules and decisions on the available budget are made at a central level (e.g., central government agency, top management), whereas the decisions on the specific measures are made at the subsystem level (e.g., local communities, company division). It is shown that the MC criterion provides optimal solutions in such hierarchical optimization. Since most practical applications only include a discrete set of possible risk protection measures, the MC criterion is extended to this situation. The findings are illustrated through a hypothetical numerical example. This study was prepared as part of our work on the optimal management of natural hazard risks, but its conclusions also apply to other fields of risk management.

  6. Solar energy for process heat: Design/cost studies of four industrial retrofit applications

    NASA Technical Reports Server (NTRS)

    French, R. L.; Bartera, R. E.

    1978-01-01

    Five specific California plants with potentially attractive solar applications were identified in a process heat survey. These five plants were visited, process requirements evaluated, and conceptual solar system designs were generated. Four DOE (ERDA) sponsored solar energy system demonstration projects were also reviewed and compared to the design/cost cases included in this report. In four of the five cases investigated, retrofit installations providing significant amounts of thermal energy were found to be feasible. The fifth was rejected because of the condition of the building involved, but the process (soap making) appears to be an attractive potential solar application. Costs, however, tend to be high. Several potential areas for cost reduction were identified including larger collector modules and higher duty cycles.

  7. Materials Development Program, Ceramic Technology Project addendum to program plan: Cost effective ceramics for heat engines

    SciTech Connect

    Not Available

    1992-08-01

    This is a new thrust in the Ceramic Technology project. This effort represents an expansion of the program and an extension through FY 1997. Moderate temperature applications in conventional automobile and truck engines will be included along with high-temp. gas turbine and low heat rejection diesel engines. The reliability goals are expected to be met on schedule by end of FY 1993. Ceramic turbine rotors have been run (in DOE`s ATTAP program) for 1000 h at 1370C and full speed. However, the cost of ceramic components is a deterrrent to near-term commercialization. A systematic approach to reducing this cost includes the following elements: economic cost modeling, ceramic machining, powder synthesis, alternative forming and densification processes, yield improvement, system design studies, standards development, and testing and data base development. A draft funding plan is outlined. 6 figs, 1 tab.

  8. Materials Development Program, Ceramic Technology Project addendum to program plan: Cost effective ceramics for heat engines

    SciTech Connect

    Not Available

    1992-08-01

    This is a new thrust in the Ceramic Technology project. This effort represents an expansion of the program and an extension through FY 1997. Moderate temperature applications in conventional automobile and truck engines will be included along with high-temp. gas turbine and low heat rejection diesel engines. The reliability goals are expected to be met on schedule by end of FY 1993. Ceramic turbine rotors have been run (in DOE's ATTAP program) for 1000 h at 1370C and full speed. However, the cost of ceramic components is a deterrrent to near-term commercialization. A systematic approach to reducing this cost includes the following elements: economic cost modeling, ceramic machining, powder synthesis, alternative forming and densification processes, yield improvement, system design studies, standards development, and testing and data base development. A draft funding plan is outlined. 6 figs, 1 tab.

  9. 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.

  10. Energy Savings and Breakeven Cost for Residential Heat Pump Water Heaters in the United States

    SciTech Connect

    Maguire, J.; Burch, J.; Merrigan, T.; Ong, S.

    2013-07-01

    Heat pump water heaters (HPWHs) have recently reemerged in the U.S. residential water heating market and have the potential to provide homeowners with significant energy savings. However, there are questions as to the actual performance and energy savings potential of these units, in particular in regards to the heat pump's performance in unconditioned space and the impact of the heat pump on space heating and cooling loads when it is located in conditioned space. To help answer these questions, simulations were performed of a HPWH in both conditioned and unconditioned space at over 900 locations across the continental United States and Hawaii. Simulations included a Building America benchmark home so that any interaction between the HPWH and the home's HVAC equipment could be captured. Comparisons were performed to typical gas and electric water heaters to determine the energy savings potential and cost effectiveness of a HPWH relative to these technologies. HPWHs were found to have a significant source energy savings potential when replacing typical electric water heaters, but only saved source energy relative to gas water heater in the most favorable installation locations in the southern US. When replacing an electric water heater, the HPWH is likely to break even in California, the southern US, and parts of the northeast in most situations. However, the HPWH will only break even when replacing a gas water heater in a few southern states.

  11. Energy Savings and Breakeven Costs for Residential Heat Pump Water Heaters in the United States

    SciTech Connect

    Maguire, Jeff; Burch, Jay; Merrigan, Tim; Ong, Sean

    2013-07-01

    Heat pump water heaters (HPWHs) have recently re-emerged in the U.S. residential water heating market and have the potential to provide homeowners with significant energy savings. However, there are questions as to the actual performance and energy savings potential of these units, in particular in regards to the heat pump's performance in unconditioned space and the impact of the heat pump on space heating and cooling loads when it is located in conditioned space. To help answer these questions, NREL performed simulations of a HPWH in both conditioned and unconditioned space at over 900 locations across the continental United States and Hawaii. Simulations included a Building America benchmark home so that any interaction between the HPWH and the home's HVAC equipment could be captured. Comparisons were performed to typical gas and electric water heaters to determine the energy savings potential and cost effectiveness of a HPWH relative to these technologies. HPWHs were found to have a significant source energy savings potential when replacing typical electric water heaters, but only saved source energy relative to gas water heater in the most favorable installation locations in the southern United States. When replacing an electric water heater, the HPWH is likely to break even in California, the southern United States, and parts of the northeast in most situations. However, the HPWH will only break even when replacing a gas water heater in a few southern states.

  12. Three-Dimensional Optimal Shape Design in Heat Transfer Based on Body-fitted Grid Generation

    NASA Astrophysics Data System (ADS)

    Mohebbi, Farzad; Sellier, Mathieu

    2013-10-01

    This paper is concerned with an optimal shape design (shape optimization) problem in heat transfer. As an inverse steady-state heat transfer problem, given a body locally heated by a specified heat flux and exposed to convective heat transfer on parts of its boundary, the aim is to find the optimal shape of this body such that the temperature is constant on a desired subset of its boundary. The numerical method to achieve this aim consists of a three-dimensional elliptic grid generation technique to generate a mesh over the body and solve for a heat conduction equation. This paper describes a novel sensitivity analysis scheme to compute the sensitivity of the temperatures to variation of grid node positions and the conjugate gradient method (CGM) is used as an optimization algorithm to minimize the difference between the computed temperature on the boundary and desired temperature. The elliptic grid generation technique allows us to map the physical domain (body) onto a fixed computational domain and to discretize the heat conduction equation using the finite difference method (FDM).

  13. Techno-economic analysis of using corn stover to supply heat and power to a corn ethanol plant - Part 2: Cost of heat and power generation systems

    SciTech Connect

    Mani, Sudhagar; Sokhansanj, Shahabaddine; Togore, Sam; Turhollow Jr, Anthony F

    2010-03-01

    This paper presents a techno-economic analysis of corn stover fired process heating (PH) and the combined heat and power (CHP) generation systems for a typical corn ethanol plant (ethanol production capacity of 170 dam3). Discounted cash flow method was used to estimate both the capital and operating costs of each system and compared with the existing natural gas fired heating system. Environmental impact assessment of using corn stover, coal and natural gas in the heat and/or power generation systems was also evaluated. Coal fired process heating (PH) system had the lowest annual operating cost due to the low fuel cost, but had the highest environmental and human toxicity impacts. The proposed combined heat and power (CHP) generation system required about 137 Gg of corn stover to generate 9.5 MW of electricity and 52.3 MW of process heat with an overall CHP efficiency of 83.3%. Stover fired CHP system would generate an annual savings of 3.6 M$ with an payback period of 6 y. Economics of the coal fired CHP system was very attractive compared to the stover fired CHP system due to lower fuel cost. But the greenhouse gas emissions per Mg of fuel for the coal fired CHP system was 32 times higher than that of stover fired CHP system. Corn stover fired heat and power generation system for a corn ethanol plant can improve the net energy balance and add environmental benefits to the corn to ethanol biorefinery.

  14. Universality of energy conversion efficiency for optimal tight-coupling heat engines and refrigerators

    NASA Astrophysics Data System (ADS)

    Sheng, Shiqi; Tu, Z. C.

    2013-10-01

    A unified χ-criterion for heat devices (including heat engines and refrigerators), which is defined as the product of the energy conversion efficiency and the heat absorbed per unit time by the working substance (de Tomás et al 2012 Phys. Rev. E 85 010104), is optimized for tight-coupling heat engines and refrigerators operating between two heat baths at temperatures Tc and Th( > Tc). By taking a new convention on the thermodynamic flux related to the heat transfer between two baths, we find that for a refrigerator tightly and symmetrically coupled with two heat baths, the coefficient of performance (i.e., the energy conversion efficiency of refrigerators) at maximum χ asymptotically approaches \\sqrt{\\varepsilon _C} when the relative temperature difference between two heat baths \\varepsilon _C^{-1}\\equiv (T_h-T_c)/T_c is sufficiently small. Correspondingly, the efficiency at maximum χ (equivalent to maximum power) for a heat engine tightly and symmetrically coupled with two heat baths is proved to be \\eta _C/2+\\eta _C^2/8 up to the second order term of ηC ≡ (Th - Tc)/Th, which reverts to the universal efficiency at maximum power for tight-coupling heat engines operating between two heat baths at small temperature difference in the presence of left-right symmetry (Esposito et al 2009 Phys. Rev. Lett. 102 130602).

  15. Optimal Shape Design in Heat Transfer Based on Body-Fitted Grid Generation

    NASA Astrophysics Data System (ADS)

    Mohebbi, Farzad; Sellier, Mathieu

    2013-04-01

    This paper deals with an inverse steady-state heat transfer problem. We develop in this work a new numerical methodology to infer the shape a heated body should have for the temperature distribution on part of its boundary to match a prescribed one. This new numerical methodology solves this shape optimization problem using body-fitted grid generation to map the unknown optimal shape onto a fixed computational domain. This mapping enables a simple discretization of the Heat Equation using finite differences and allows us to remesh the physical domain, which varies at each optimization iteration. A novel aspect of this work is the sensitivity analysis, which is expressed explicitly in the fixed computational domain. This allows a very efficient evaluation of the sensitivities. The Conjugate Gradient method is used to minimize the objective function and this work proposes an efficient redistribution method to maintain the quality of the mesh throughout the optimization procedure.

  16. Development of a Low Cost Heat Pump Water Heater - First Prototype

    SciTech Connect

    Mei, V. C.; Tomlinson, J. J.

    2007-09-01

    Until now the heat pump water heater (HPWH) has been a technical success but a market failure because of its high initial cost. Oak Ridge National Laboratory (ORNL) was tasked to examine commercially available HPWH product technology and manufacturing processes for cost saving opportunities. ORNL was also tasked to verify the technical feasibility of the cost saving opportunities where necessary and appropriate. The objective was to retain most of the HPWH s energy saving performance while reducing cost and simple payback period to approximately three years in a residential application. Several cost saving opportunities were found. Immersing the HPWH condenser directly into the tank allowed the water-circulating pump to be eliminated and a standard electric resistance storage water heater to be used. In addition, designs could be based on refrigerator compressors. Standard water heaters and refrigerator compressors are both reliable, mass produced, and low cost. To verify the feasibility of these cost saving measures, ORNL completed a conceptual design for an HPWH based on an immersed condenser coil that could be directly inserted into a standard water heater tank through a sleeve affixed to one of the standard penetrations at the top of the tank. The sleeve contour causes the bayonet-style condenser to helix while being pushed into the tank, enabling a condenser of sufficient heat transfer surface area to be inserted. Based on this design, ORNL fabricated the first laboratory prototype and completed preliminary laboratory tests in accordance with the DOE Simulated Use Test Procedure. Hardening during double-wall condenser fabrication was not overcome, so the prototype is single-walled with a liner. The prototype unit was found to have an energy factor of 2.02, verifying that the low-cost design retains most of the HPWH s energy saving performance. Industry involvement is being sought to resolve the fabrication issue and quantify progress on reducing cost and

  17. Optimal actuator location of minimum norm controls for heat equation with general controlled domain

    NASA Astrophysics Data System (ADS)

    Guo, Bao-Zhu; Xu, Yashan; Yang, Dong-Hui

    2016-09-01

    In this paper, we study optimal actuator location of the minimum norm controls for a multi-dimensional heat equation with control defined in the space L2 (Ω × (0 , T)). The actuator domain is time-varying in the sense that it is only required to have a prescribed Lebesgue measure for any moment. We select an optimal actuator location so that the optimal control takes its minimal norm over all possible actuator domains. We build a framework of finding the Nash equilibrium so that we can develop a sufficient and necessary condition to characterize the optimal relaxed solutions for both actuator location and corresponding optimal control of the open-loop system. The existence and uniqueness of the optimal classical solutions are therefore concluded. As a result, we synthesize both optimal actuator location and corresponding optimal control into a time-varying feedbacks.

  18. Developing, testing, evaluating and optimizing solar heating and cooling systems

    SciTech Connect

    Not Available

    1992-01-24

    The objective is to develop and test various integrated solar heating, cooling and domestic hot water systems, and to evaluate their performance. Systems composed of new, as well as previously tested, components are carefully integrated so that effects of new components on system performance can be clearly delineated. The SEAL-DOE program includes six tasks which have received funding for the 1991--92 fifteen-month period. These include: (1) a project employing isothermal operation of air and liquid solar space heating systems; (2) a project to build and test several generic solar water heaters; (3) a project that will evaluate advanced solar domestic hot water components and concepts and integrate them into solar domestic hot water systems; (4) a liquid desiccant cooling system development project; (5) a project that will perform system modeling and analysis work on solid desiccant cooling systems research; and (6) a management task. The objectives and progress in each task are described in this report.

  19. Plug-in hybrid electric vehicle charge pattern optimization for energy cost and battery longevity

    NASA Astrophysics Data System (ADS)

    Bashash, Saeid; Moura, Scott J.; Forman, Joel C.; Fathy, Hosam K.

    This paper examines the problem of optimizing the charge pattern of a plug-in hybrid electric vehicle (PHEV), defined as the timing and rate with which the PHEV obtains electricity from the power grid. The optimization goal is to simultaneously minimize (i) the total cost of fuel and electricity and (ii) the total battery health degradation over a 24-h naturalistic drive cycle. The first objective is calculated for a previously-developed stochastic optimal PHEV power management strategy, whereas the second objective is evaluated through an electrochemistry-based model of anode-side resistive film formation in lithium-ion batteries. The paper shows that these two objectives are conflicting, and trades them off using a non-dominated sorting genetic algorithm. As a result, a Pareto front of optimal charge patterns is obtained. The effects of electricity price and trip schedule on the optimal Pareto points and the PHEV charge patterns are analyzed and discussed.

  20. Robotic lower limb prosthesis design through simultaneous computer optimizations of human and prosthesis costs

    NASA Astrophysics Data System (ADS)

    Handford, Matthew L.; Srinivasan, Manoj

    2016-02-01

    Robotic lower limb prostheses can improve the quality of life for amputees. Development of such devices, currently dominated by long prototyping periods, could be sped up by predictive simulations. In contrast to some amputee simulations which track experimentally determined non-amputee walking kinematics, here, we explicitly model the human-prosthesis interaction to produce a prediction of the user’s walking kinematics. We obtain simulations of an amputee using an ankle-foot prosthesis by simultaneously optimizing human movements and prosthesis actuation, minimizing a weighted sum of human metabolic and prosthesis costs. The resulting Pareto optimal solutions predict that increasing prosthesis energy cost, decreasing prosthesis mass, and allowing asymmetric gaits all decrease human metabolic rate for a given speed and alter human kinematics. The metabolic rates increase monotonically with speed. Remarkably, by performing an analogous optimization for a non-amputee human, we predict that an amputee walking with an appropriately optimized robotic prosthesis can have a lower metabolic cost – even lower than assuming that the non-amputee’s ankle torques are cost-free.

  1. Constrained Optimization Problems in Cost and Managerial Accounting--Spreadsheet Tools

    ERIC Educational Resources Information Center

    Amlie, Thomas T.

    2009-01-01

    A common problem addressed in Managerial and Cost Accounting classes is that of selecting an optimal production mix given scarce resources. That is, if a firm produces a number of different products, and is faced with scarce resources (e.g., limitations on labor, materials, or machine time), what combination of products yields the greatest profit…

  2. Robotic lower limb prosthesis design through simultaneous computer optimizations of human and prosthesis costs.

    PubMed

    Handford, Matthew L; Srinivasan, Manoj

    2016-02-09

    Robotic lower limb prostheses can improve the quality of life for amputees. Development of such devices, currently dominated by long prototyping periods, could be sped up by predictive simulations. In contrast to some amputee simulations which track experimentally determined non-amputee walking kinematics, here, we explicitly model the human-prosthesis interaction to produce a prediction of the user's walking kinematics. We obtain simulations of an amputee using an ankle-foot prosthesis by simultaneously optimizing human movements and prosthesis actuation, minimizing a weighted sum of human metabolic and prosthesis costs. The resulting Pareto optimal solutions predict that increasing prosthesis energy cost, decreasing prosthesis mass, and allowing asymmetric gaits all decrease human metabolic rate for a given speed and alter human kinematics. The metabolic rates increase monotonically with speed. Remarkably, by performing an analogous optimization for a non-amputee human, we predict that an amputee walking with an appropriately optimized robotic prosthesis can have a lower metabolic cost--even lower than assuming that the non-amputee's ankle torques are cost-free.

  3. Robotic lower limb prosthesis design through simultaneous computer optimizations of human and prosthesis costs

    PubMed Central

    Handford, Matthew L.; Srinivasan, Manoj

    2016-01-01

    Robotic lower limb prostheses can improve the quality of life for amputees. Development of such devices, currently dominated by long prototyping periods, could be sped up by predictive simulations. In contrast to some amputee simulations which track experimentally determined non-amputee walking kinematics, here, we explicitly model the human-prosthesis interaction to produce a prediction of the user’s walking kinematics. We obtain simulations of an amputee using an ankle-foot prosthesis by simultaneously optimizing human movements and prosthesis actuation, minimizing a weighted sum of human metabolic and prosthesis costs. The resulting Pareto optimal solutions predict that increasing prosthesis energy cost, decreasing prosthesis mass, and allowing asymmetric gaits all decrease human metabolic rate for a given speed and alter human kinematics. The metabolic rates increase monotonically with speed. Remarkably, by performing an analogous optimization for a non-amputee human, we predict that an amputee walking with an appropriately optimized robotic prosthesis can have a lower metabolic cost – even lower than assuming that the non-amputee’s ankle torques are cost-free. PMID:26857747

  4. Energy cost based design optimization method for medium temperature CPC collectors

    NASA Astrophysics Data System (ADS)

    Horta, Pedro; Osório, Tiago; Collares-Pereira, Manuel

    2016-05-01

    CPC collectors, approaching the ideal concentration limits established by non-imaging optics, can be designed to have such acceptance angles enabling fully stationary designs, useful for applications in the low temperature range (T < 100°C). Their use in the medium temperature range (100°C < T < 250°C) typically requires higher concentration factors in turn requiring seasonal tracking strategies. Considering the CPC design options in terms of effective concentration factor, truncation, concentrator height, mirror perimeter, seasonal tracking, trough spacing, etc., an energy cost function based design optimization method is presented in this article. Accounting for the impact of the design on its optical (optical efficiency, Incidence Angle Modifier, diffuse acceptance) and thermal performances (dependent on the concentration factor), the optimization function integrates design (e.g. mirror area, frame length, trough spacing/shading), concept (e.g. rotating/stationary components, materials) and operation (e.g. O&M, tilt shifts and tracking strategy) costs into a collector specific energy cost function, in €/(kWh.m2). The use of such function stands for a location and operating temperature dependent design optimization procedure, aiming at the lowest solar energy cost. Illustrating this approach, optimization results will be presented for a (tubular) evacuated absorber CPC design operating in Morocco.

  5. Optimization of inulinase production from low cost substrates using Plackett-Burman and Taguchi methods.

    PubMed

    Abd El Aty, Abeer A; Wehaidy, Hala R; Mostafa, Faten A

    2014-02-15

    Four marine-derived fungal isolates were screened for the production of inulinase enzyme from low cost substrates under solid state fermentation (SSF), one of them identified as Aspergillus terreus showed the highest inulinase activity using artichoke leaves as a solid substrate. Sequential optimization strategy, based on statistical experimental designs was employed to optimize the composition of the medium, including Plackett-Burman and Taguchi's (L9 3(4)) orthogonal array designs. Under the optimized conditions, inulinase activity (21.058 U/gds) reached the predicted maximum activity derived from the taguchi methodology, which increased about 4.79-folds the initial production medium. Fructose was produced, as an end product of inulin hydrolysis proving that the enzyme produced was exoinulinase. The marine-derived A. terreus is suggested as a new potential candidate for industrial enzymatic production of fructose from low cost substrate containing inulin as an economic source.

  6. Incorporation of Fixed Installation Costs into Optimization of Groundwater Remediation with a New Efficient Surrogate Nonlinear Mixed Integer Optimization Algorithm

    NASA Astrophysics Data System (ADS)

    Shoemaker, Christine; Wan, Ying

    2016-04-01

    Optimization of nonlinear water resources management issues which have a mixture of fixed (e.g. construction cost for a well) and variable (e.g. cost per gallon of water pumped) costs has been not well addressed because prior algorithms for the resulting nonlinear mixed integer problems have required many groundwater simulations (with different configurations of decision variable), especially when the solution space is multimodal. In particular heuristic methods like genetic algorithms have often been used in the water resources area, but they require so many groundwater simulations that only small systems have been solved. Hence there is a need to have a method that reduces the number of expensive groundwater simulations. A recently published algorithm for nonlinear mixed integer programming using surrogates was shown in this study to greatly reduce the computational effort for obtaining accurate answers to problems involving fixed costs for well construction as well as variable costs for pumping because of a substantial reduction in the number of groundwater simulations required to obtain an accurate answer. Results are presented for a US EPA hazardous waste site. The nonlinear mixed integer surrogate algorithm is general and can be used on other problems arising in hydrology with open source codes in Matlab and python ("pySOT" in Bitbucket).

  7. Reconstruction of the unknown optimization cost functions from experimental recordings during static multi-finger prehension

    PubMed Central

    Niu, Xun; Terekhov, Alexander V.; Latash, Mark L.; Zatsiorsky, Vladimir M.

    2013-01-01

    The goal of the research is to reconstruct the unknown cost (objective) function(s) presumably used by the neural controller for sharing the total force among individual fingers in multi-finger prehension. The cost function was determined from experimental data by applying the recently developed Analytical Inverse Optimization (ANIO) method (Terekhov et al 2010). The core of the ANIO method is the Theorem of Uniqueness that specifies conditions for unique (with some restrictions) estimation of the objective functions. In the experiment, subjects (n=8) grasped an instrumented handle and maintained it at rest in the air with various external torques, loads, and target grasping forces applied to the object. The experimental data recorded from 80 trials showed a tendency to lie on a 2-dimensional hyperplane in the 4-dimensional finger-force space. Because the constraints in each trial were different, such a propensity is a manifestation of a neural mechanism (not the task mechanics). In agreement with the Lagrange principle for the inverse optimization, the plane of experimental observations was close to the plane resulting from the direct optimization. The latter plane was determined using the ANIO method. The unknown cost function was reconstructed successfully for each performer, as well as for the group data. The cost functions were found to be quadratic with non-zero linear terms. The cost functions obtained with the ANIO method yielded more accurate results than other optimization methods. The ANIO method has an evident potential for addressing the problem of optimization in motor control. PMID:22104742

  8. Optimal lift and bank modulations for three-dimensional reentry trajectories with heat constraint

    NASA Astrophysics Data System (ADS)

    Chern, Jeng-Shing; Yang, Ching-Yew; Sheen, Jyh-Jong

    For hypersonic reentry flight, the heat problem is usually the most severe problem. Therefore, it is of necessity and interest to consider the heat constraint in solving optimal reentry trajectories. This paper, under the facilities of the continuation method and the multiple shooting method, investigates the optimal lift and bank modulations for three-dimensional reentry trajectories with heating rate constraint. The modified Newton method is used to induce and accelerate convergence. From the variational formulation, the optimal lift and bank control laws and the transversality conditions are derived. The non-constrained optimal trajectories leading to the boundary of the maximum reachable domain of a typical lifting reentry vehicle are solved at first. It is a three-parameter two-point boundary-value problem. Then the heating rate constraint is imposed and the constrained maximum reachable domain is constructed finally. Because the equilibrium glide condition is eliminated in this paper, the maximum reachable domain obtained is larger than the one obtained under the equilibrium glide assumption. Besides, both optimal lift and optimal bank control histories are presented and discussed.

  9. Co-optimizing carbon nanotube synthesis: control of diameter, structural quality, and growth kinetics along with simultaneous cost minimization

    NASA Astrophysics Data System (ADS)

    Meshot, Eric R.; Plata, Desireé L.; Reddy, Christopher M.; Gschwend, Philip M.; Hart, A. John

    2009-03-01

    We employ a decoupled CVD method that not only facilitates control of mean diameter and structural quality of vertically aligned CNTs, but also co-optimization of kinetics for efficient growth to ``forest'' heights of several millimeters. The growth substrate temperature (Ts) governs agglomeration of the catalyst film which primarily determines CNT diameter, while structural quality monotonically increases with Ts. Independent heating (Tp) of the reactant mixture generates a strikingly diverse population of active hydrocarbons. These analyses, in concert with real-time laser measurements of forest growth rate and height suggest that select products of gas treatment promote growth, while excessive gas-phase pyrolysis of hydrocarbons adversely affects the CNT structure. Further, we directly inject select compounds in the absence of thermal treatment, thus minimizing energetic costs.

  10. Optimization of solar cell contacts by system cost-per-watt minimization

    NASA Technical Reports Server (NTRS)

    Redfield, D.

    1977-01-01

    New, and considerably altered, optimum dimensions for solar-cell metallization patterns are found using the recently developed procedure whose optimization criterion is the minimum cost-per-watt effect on the entire photovoltaic system. It is also found that the optimum shadow fraction by the fine grid is independent of metal cost and resistivity as well as cell size. The optimum thickness of the fine grid metal depends on all these factors, and in familiar cases it should be appreciably greater than that found by less complete analyses. The optimum bus bar thickness is much greater than those generally used. The cost-per-watt penalty due to the need for increased amounts of metal per unit area on larger cells is determined quantitatively and thereby provides a criterion for the minimum benefits that must be obtained in other process steps to make larger cells cost effective.

  11. Potential escalation of heat-related working costs with climate and socioeconomic changes in China

    PubMed Central

    Zhao, Yan; Sultan, Benjamin; Vautard, Robert; Braconnot, Pascale; Wang, Huijun J.; Ducharne, Agnes

    2016-01-01

    Global climate change will increase the frequency of hot temperatures, impairing health and productivity for millions of working people and raising labor costs. In mainland China, high-temperature subsidies (HTSs) are allocated to employees for each working day in extremely hot environments, but the potential heat-related increase in labor cost has not been evaluated so far. Here, we estimate the potential HTS cost in current and future climates under different scenarios of socioeconomic development and radiative forcing (Representative Concentration Pathway), taking uncertainties from the climate model structure and bias correction into account. On average, the total HTS in China is estimated at 38.6 billion yuan/y (US $6.22 billion/y) over the 1979–2005 period, which is equivalent to 0.2% of the gross domestic product (GDP). Assuming that the HTS standards (per employee per hot day) remain unchanged throughout the 21st century, the total HTS may reach 250 billion yuan/y in the 2030s and 1,000 billion yuan/y in 2100. We further show that, without specific adaptation, the increased HTS cost is mainly determined by population growth until the 2030s and climate change after the mid-21st century because of increasingly frequent hot weather. Accounting for the likely possibility that HTS standards follow the wages, the share of GDP devoted to HTS could become as high as 3% at the end of 21st century. PMID:27044089

  12. Potential escalation of heat-related working costs with climate and socioeconomic changes in China.

    PubMed

    Zhao, Yan; Sultan, Benjamin; Vautard, Robert; Braconnot, Pascale; Wang, Huijun J; Ducharne, Agnes

    2016-04-26

    Global climate change will increase the frequency of hot temperatures, impairing health and productivity for millions of working people and raising labor costs. In mainland China, high-temperature subsidies (HTSs) are allocated to employees for each working day in extremely hot environments, but the potential heat-related increase in labor cost has not been evaluated so far. Here, we estimate the potential HTS cost in current and future climates under different scenarios of socioeconomic development and radiative forcing (Representative Concentration Pathway), taking uncertainties from the climate model structure and bias correction into account. On average, the total HTS in China is estimated at 38.6 billion yuan/y (US $6.22 billion/y) over the 1979-2005 period, which is equivalent to 0.2% of the gross domestic product (GDP). Assuming that the HTS standards (per employee per hot day) remain unchanged throughout the 21st century, the total HTS may reach 250 billion yuan/y in the 2030s and 1,000 billion yuan/y in 2100. We further show that, without specific adaptation, the increased HTS cost is mainly determined by population growth until the 2030s and climate change after the mid-21st century because of increasingly frequent hot weather. Accounting for the likely possibility that HTS standards follow the wages, the share of GDP devoted to HTS could become as high as 3% at the end of 21st century.

  13. Optimal Design of a Thermoelectric Cooling/Heating System for Car Seat Climate Control (CSCC)

    NASA Astrophysics Data System (ADS)

    Elarusi, Abdulmunaem; Attar, Alaa; Lee, Hosung

    2016-12-01

    In the present work, the optimum design of thermoelectric car seat climate control (CSCC) is studied analytically in an attempt to achieve high system efficiency. Optimal design of a thermoelectric device (element length, cross-section area and number of thermocouples) is carried out using our newly developed optimization method based on the ideal thermoelectric equations and dimensional analysis to improve the performance of the thermoelectric device in terms of the heating/cooling power and the coefficient of performance (COP). Then, a new innovative system design is introduced which also includes the optimum input current for the initial (transient) startup warming and cooling before the car heating ventilation and air conditioner (HVAC) is active in the cabin. The air-to-air heat exchanger's configuration was taken into account to investigate the optimal design of the CSCC.

  14. Optimal Design of a Thermoelectric Cooling/Heating System for Car Seat Climate Control (CSCC)

    NASA Astrophysics Data System (ADS)

    Elarusi, Abdulmunaem; Attar, Alaa; Lee, Hosung

    2017-04-01

    In the present work, the optimum design of thermoelectric car seat climate control (CSCC) is studied analytically in an attempt to achieve high system efficiency. Optimal design of a thermoelectric device (element length, cross-section area and number of thermocouples) is carried out using our newly developed optimization method based on the ideal thermoelectric equations and dimensional analysis to improve the performance of the thermoelectric device in terms of the heating/cooling power and the coefficient of performance (COP). Then, a new innovative system design is introduced which also includes the optimum input current for the initial (transient) startup warming and cooling before the car heating ventilation and air conditioner (HVAC) is active in the cabin. The air-to-air heat exchanger's configuration was taken into account to investigate the optimal design of the CSCC.

  15. Optimization of automotive Rankine cycle waste heat recovery under various engine operating condition

    NASA Astrophysics Data System (ADS)

    Punov, Plamen; Milkov, Nikolay; Danel, Quentin; Perilhon, Christelle; Podevin, Pierre; Evtimov, Teodossi

    2017-02-01

    An optimization study of the Rankine cycle as a function of diesel engine operating mode is presented. The Rankine cycle here, is studied as a waste heat recovery system which uses the engine exhaust gases as heat source. The engine exhaust gases parameters (temperature, mass flow and composition) were defined by means of numerical simulation in advanced simulation software AVL Boost. Previously, the engine simulation model was validated and the Vibe function parameters were defined as a function of engine load. The Rankine cycle output power and efficiency was numerically estimated by means of a simulation code in Python(x,y). This code includes discretized heat exchanger model and simplified model of the pump and the expander based on their isentropic efficiency. The Rankine cycle simulation revealed the optimum value of working fluid mass flow and evaporation pressure according to the heat source. Thus, the optimal Rankine cycle performance was obtained over the engine operating map.

  16. Developing, testing, evaluating and optimizing solar heating and cooling systems

    NASA Astrophysics Data System (ADS)

    Karaki, S.

    1989-05-01

    The objective is to develop and test various integrated solar heating, cooling and domestic hot water systems, and to evaluate their performance. Systems composed of new, as well as previously tested, components are carefully integrated so that effects of new components on system performance can be clearly delineated. The program for 1989-90 is separated into seven tasks. There are asks for each of the three solar houses, a project to build and test several generic solar water heaters, a task involving development of an improved evacuated tube collector, a management task, and a task under which an international workshop will test IEA Task 4 models. The objectives and progress in each task are described in this report.

  17. Vaccination and treatment as control interventions in an infectious disease model with their cost optimization

    NASA Astrophysics Data System (ADS)

    Kumar, Anuj; Srivastava, Prashant K.

    2017-03-01

    In this work, an optimal control problem with vaccination and treatment as control policies is proposed and analysed for an SVIR model. We choose vaccination and treatment as control policies because both these interventions have their own practical advantage and ease in implementation. Also, they are widely applied to control or curtail a disease. The corresponding total cost incurred is considered as weighted combination of costs because of opportunity loss due to infected individuals and costs incurred in providing vaccination and treatment. The existence of optimal control paths for the problem is established and guaranteed. Further, these optimal paths are obtained analytically using Pontryagin's Maximum Principle. We analyse our results numerically to compare three important strategies of proposed controls, viz.: vaccination only; with both treatment and vaccination; and treatment only. We note that first strategy (vaccination only) is less effective as well as expensive. Though, for a highly effective vaccine, vaccination alone may also work well in comparison with treatment only strategy. Among all the strategies, we observe that implementation of both treatment and vaccination is most effective and less expensive. Moreover, in this case the infective population is found to be relatively very low. Thus, we conclude that the comprehensive effect of vaccination and treatment not only minimizes cost burden due to opportunity loss and applied control policies but also keeps a tab on infective population.

  18. Predicting stomatal responses to the environment from the optimization of photosynthetic gain and hydraulic cost.

    PubMed

    Sperry, John S; Venturas, Martin D; Anderegg, William R L; Mencuccini, Maurizio; Mackay, D Scott; Wang, Yujie; Love, David M

    2016-10-20

    Stomatal regulation presumably evolved to optimize CO2 for H2 O exchange in response to changing conditions. If the optimization criterion can be readily measured or calculated, then stomatal responses can be efficiently modelled without recourse to empirical models or underlying mechanism. Previous efforts have been challenged by the lack of a transparent index for the cost of losing water. Yet it is accepted that stomata control water loss to avoid excessive loss of hydraulic conductance from cavitation and soil drying. Proximity to hydraulic failure and desiccation can represent the cost of water loss. If at any given instant, the stomatal aperture adjusts to maximize the instantaneous difference between photosynthetic gain and hydraulic cost, then a model can predict the trajectory of stomatal responses to changes in environment across time. Results of this optimization model are consistent with the widely used Ball-Berry-Leuning empirical model (r(2)  > 0.99) across a wide range of vapour pressure deficits and ambient CO2 concentrations for wet soil. The advantage of the optimization approach is the absence of empirical coefficients, applicability to dry as well as wet soil and prediction of plant hydraulic status along with gas exchange.

  19. Data of cost-optimal solutions and retrofit design methods for school renovation in a warm climate.

    PubMed

    Zacà, Ilaria; Tornese, Giuliano; Baglivo, Cristina; Congedo, Paolo Maria; D'Agostino, Delia

    2016-12-01

    "Efficient Solutions and Cost-Optimal Analysis for Existing School Buildings" (Paolo Maria Congedo, Delia D'Agostino, Cristina Baglivo, Giuliano Tornese, Ilaria Zacà) [1] is the paper that refers to this article. It reports the data related to the establishment of several variants of energy efficient retrofit measures selected for two existing school buildings located in the Mediterranean area. In compliance with the cost-optimal analysis described in the Energy Performance of Buildings Directive and its guidelines (EU, Directive, EU 244,) [2], [3], these data are useful for the integration of renewable energy sources and high performance technical systems for school renovation. The data of cost-efficient high performance solutions are provided in tables that are explained within the following sections. The data focus on the describe school refurbishment sector to which European policies and investments are directed. A methodological approach already used in previous studies about new buildings is followed (Baglivo Cristina, Congedo Paolo Maria, D׳Agostino Delia, Zacà Ilaria, 2015; IlariaZacà, Delia D'Agostino, Paolo Maria Congedo, Cristina Baglivo; Baglivo Cristina, Congedo Paolo Maria, D'Agostino Delia, Zacà Ilaria, 2015; Ilaria Zacà, Delia D'Agostino, Paolo Maria Congedo, Cristina Baglivo, 2015; Paolo Maria Congedo, Cristina Baglivo, IlariaZacà, Delia D'Agostino,2015) [4], [5], [6], [7], [8]. The files give the cost-optimal solutions for a kindergarten (REF1) and a nursery (REF2) school located in Sanarica and Squinzano (province of Lecce Southern Italy). The two reference buildings differ for construction period, materials and systems. The eleven tables provided contain data about the localization of the buildings, geometrical features and thermal properties of the envelope, as well as the energy efficiency measures related to walls, windows, heating, cooling, dhw and renewables. Output values of energy consumption, gas emission and costs are given for a

  20. Low-cost functional plasticity of TRPV1 supports heat tolerance in squirrels and camels

    PubMed Central

    Laursen, Willem J.; Merriman, Dana K.; Bagriantsev, Sviatoslav N.; Gracheva, Elena O.

    2016-01-01

    The ability to sense heat is crucial for survival. Increased heat tolerance may prove beneficial by conferring the ability to inhabit otherwise prohibitive ecological niches. This phenomenon is widespread and is found in both large and small animals. For example, ground squirrels and camels can tolerate temperatures more than 40 °C better than many other mammalian species, yet a molecular mechanism subserving this ability is unclear. Transient receptor potential vanilloid 1 (TRPV1) is a polymodal ion channel involved in the detection of noxious thermal and chemical stimuli by primary afferents of the somatosensory system. Here, we show that thirteen-lined ground squirrels (Ictidomys tridecemlineatus) and Bactrian camels (Camelus ferus) express TRPV1 orthologs with dramatically reduced temperature sensitivity. The loss of sensitivity is restricted to temperature and does not affect capsaicin or acid responses, thereby maintaining a role for TRPV1 as a detector of noxious chemical cues. We show that heat sensitivity can be reengineered in both TRPV1 orthologs by a single amino acid substitution in the N-terminal ankyrin-repeat domain. Conversely, reciprocal mutations suppress heat sensitivity of rat TRPV1, supporting functional conservation of the residues. Our studies suggest that squirrels and camels co-opt a common molecular strategy to adapt to hot environments by suppressing the efficiency of TRPV1-mediated heat detection at the level of somatosensory neurons. Such adaptation is possible because of the remarkable functional flexibility of the TRPV1 molecule, which can undergo profound tuning at the minimal cost of a single amino acid change. PMID:27638213

  1. Development and evaluation of low cost honey heating-cum-filtration system.

    PubMed

    Alam, Md Shafiq; Sharma, D K; Sehgal, V K; Arora, M; Bhatia, S

    2014-11-01

    A fully mechanized honey heating-cum-filtration system was designed, developed, fabricated and evaluated for its performance. The system comprised of two sections; the top heating section and the lower filtering section. The developed system was evaluated for its performance at different process conditions (25 kg and 50 kg capacity using processing condition: 50 °C heating temperature and 60 °C heating temperature with 20 and 40 min holding time, respectively) and it was found that the total time required for heating, holding and filtration of honey was 108 and 142 min for 25 kg and 50 kg capacity of machine, respectively, irrespective of the processing conditions. The optimum capacity of the system was found to be 50 kg and it involved an investment of Rs 40,000 for its fabrication. The honey filtered through the developed filtration system was compared with the honey filtered in a high cost honey processing plant and raw honey for its microbial and biochemical (reducing sugars (%), moisture, acidity and pH) quality attributes. It was observed that the process of filtering through the developed unit resulted in reduction of microbes. The microbiological quality of honey filtered through the developed filtration system was better than that of raw honey and commercially processed honey. The treatment conditions found best in context of microbiological counts were 60 °C temperature for 20 min. There was 1.97 fold reductions in the plate count and 2.14 reductions in the fungal count of honey processed through the developed filtration system as compared to the raw honey. No coliforms were found in the processed honey. Honey processed through developed unit witnessed less moisture content, acidity and more reducing sugars as compared to raw honey, whereas its quality was comparable to the commercially processed honey.

  2. Low-cost functional plasticity of TRPV1 supports heat tolerance in squirrels and camels.

    PubMed

    Laursen, Willem J; Schneider, Eve R; Merriman, Dana K; Bagriantsev, Sviatoslav N; Gracheva, Elena O

    2016-10-04

    The ability to sense heat is crucial for survival. Increased heat tolerance may prove beneficial by conferring the ability to inhabit otherwise prohibitive ecological niches. This phenomenon is widespread and is found in both large and small animals. For example, ground squirrels and camels can tolerate temperatures more than 40 °C better than many other mammalian species, yet a molecular mechanism subserving this ability is unclear. Transient receptor potential vanilloid 1 (TRPV1) is a polymodal ion channel involved in the detection of noxious thermal and chemical stimuli by primary afferents of the somatosensory system. Here, we show that thirteen-lined ground squirrels (Ictidomys tridecemlineatus) and Bactrian camels (Camelus ferus) express TRPV1 orthologs with dramatically reduced temperature sensitivity. The loss of sensitivity is restricted to temperature and does not affect capsaicin or acid responses, thereby maintaining a role for TRPV1 as a detector of noxious chemical cues. We show that heat sensitivity can be reengineered in both TRPV1 orthologs by a single amino acid substitution in the N-terminal ankyrin-repeat domain. Conversely, reciprocal mutations suppress heat sensitivity of rat TRPV1, supporting functional conservation of the residues. Our studies suggest that squirrels and camels co-opt a common molecular strategy to adapt to hot environments by suppressing the efficiency of TRPV1-mediated heat detection at the level of somatosensory neurons. Such adaptation is possible because of the remarkable functional flexibility of the TRPV1 molecule, which can undergo profound tuning at the minimal cost of a single amino acid change.

  3. S-PRIME Heat Transport and Heat Rejection Subsystems Design Optimization

    NASA Astrophysics Data System (ADS)

    Moriarty, Michael P.

    1994-07-01

    The purpose of this paper is to describe the design status of the Rocketdyne space power reactor, incore, multicell, evolutionary (S-PRIME) design of the heat transport and heat rejection subsystems. The basic design concept is similar to that described previously; however, several detail design changes have resulted from changes in requirements. Improved definition of the various loop components has evolved from the performance of various trade studies. Overall layouts of the subsystem have been completed and the majority of the components are ready for preliminary design. The design will provide for the safe and reliable cooling of the nuclear reactor in a proven lightweight configuration.

  4. Development of GIS-Based Decision Support System for Optimizing Transportation Cost in Underground Limestone Mining

    NASA Astrophysics Data System (ADS)

    Oh, Sungchan; Park, Jihwan; Suh, Jangwon; Lee, Sangho; Choi, Youngmin

    2014-05-01

    In mining industry, large amount of cost has been invested in early stages of mine development such as prospecting, exploration, and discovery. Recent changes in mining, however, also raised the cost in operation, production, and environmental protection because ore depletion at shallow depth caused large-scale, deep mining. Therefore, many mining facilities are installed or relocated underground to reduce transportation cost as well as environmental pollution. This study presents GIS-based decision support system that optimizes transportation cost from various mining faces to mine facility in underground mines. The development of this system consists of five steps. As a first step, mining maps were collected which contains underground geo-spatial informations. In mine maps, then, mine network and contour data were converted to GIS format in second step for 3D visualization and spatial analysis. In doing so, original tunnel outline data were digitized with ground level, and converted to simplified network format, and surface morphology, contours were converted to digital elevation model (DEM). The next step is to define calculation algorithm of transportation cost. Among the many component of transportation cost, this study focused on the fuel cost because it can be easily estimated if mining maps are available by itself. The cost were calculated by multiplication of the number of blasting, haulage per blasting, distance between mining faces to facility, fuel cost per liter, and two for downhill and uphill, divided by fuel efficiency of mining trucks. Finally, decision support system, SNUTunnel was implemented. For the application of SNUTunnel in actual underground mine, Nammyeong Development Corporation, Korea, was selected as study site. This mine produces limestone with high content of calcite for paper, steel manufacture, or desulfurization, and its development is continuously ongoing to reach down to deeper calcite ore body, so the mine network is expanding

  5. Transient analysis and energy optimization of solar heating and cooling systems in various configurations

    SciTech Connect

    Calise, F.; Dentice d'Accadia, M.; Palombo, A.

    2010-03-15

    In this paper, a transient simulation model of solar-assisted heating and cooling systems (SHC) is presented. A detailed case study is also discussed, in which three different configurations are considered. In all cases, the SHC system is based on the coupling of evacuated solar collectors with a single-stage LiBr-H{sub 2}O absorption chiller, and a gas-fired boiler is also included for auxiliary heating, only during the winter season. In the first configuration, the cooling capacity of the absorption chiller and the solar collector area are designed on the basis of the maximum cooling load, and an electric chiller is used as the auxiliary cooling system. The second layout is similar to the first one, but, in this case, the absorption chiller and the solar collector area are sized in order to balance only a fraction of the maximum cooling load. Finally, in the third configuration, there is no electric chiller, and the auxiliary gas-fired boiler is also used in summer to feed the absorption chiller, in case of scarce solar irradiation. The simulation model was developed using the TRNSYS software, and included the analysis of the dynamic behaviour of the building in which the SHC systems were supposed to be installed. The building was simulated using a single-lumped capacitance model. An economic model was also developed, in order to assess the operating and capital costs of the systems under analysis. Furthermore, a mixed heuristic-deterministic optimization algorithm was implemented, in order to determine the set of the synthesis/design variables that maximize the energy efficiency of each configuration under analysis. The results of the case study were analyzed on monthly and weekly basis, paying special attention to the energy and monetary flows of the standard and optimized configurations. The results are encouraging as for the potential of energy saving. On the contrary, the SHC systems appear still far from the economic profitability: however, this is

  6. Design optimization of heat transfer and fluidic devices by using additive manufacturing

    NASA Astrophysics Data System (ADS)

    Kumar, Nikhil

    After the development of additive manufacturing technology in the 1980s, it has found use in many applications like aerospace, automotive, marine, machinery, consumer and electronic applications. In recent time, few researchers have worked on the applications of additive manufacturing for heat transfer and fluidic devices. As the world has seen a drastic increase in population in last decades which have put stress on already scarce energy resources, optimization of energy devices which include energy storing devices, heat transfer devices, energy capturing devices etc. is need for the hour. Design of energy devices is often constrained by manufacturing constraints thus current design of energy devices is not an optimized one. In this research we want to conceptualize, design and manufacture optimized heat transfer and fluidic devices by exploiting the advantages provided by additive manufacturing. We want to benefit from the fact that very intricate geometry and desired surface finish can be obtained by using additive manufacturing. Additionally, we want to compare the efficacy of our designed device with conventional devices. Work on usage of Additive manufacturing for increasing efficiency of heat transfer devices can be found in the literature. We want to extend this approach to other heat transfer devices especially tubes with internal flow. By optimizing the design of energy systems we hope to solve current energy shortage and help conserve energy for future generation. We will also extend the application of additive manufacturing technology to fabricate "device for uniform flow distribution".

  7. Taguchi Approach to Design Optimization for Quality and Cost: An Overview

    NASA Technical Reports Server (NTRS)

    Unal, Resit; Dean, Edwin B.

    1990-01-01

    Calibrations to existing cost of doing business in space indicate that to establish human presence on the Moon and Mars with the Space Exploration Initiative (SEI) will require resources, felt by many, to be more than the national budget can afford. In order for SEI to succeed, we must actually design and build space systems at lower cost this time, even with tremendous increases in quality and performance requirements, such as extremely high reliability. This implies that both government and industry must change the way they do business. Therefore, new philosophy and technology must be employed to design and produce reliable, high quality space systems at low cost. In recognizing the need to reduce cost and improve quality and productivity, Department of Defense (DoD) and National Aeronautics and Space Administration (NASA) have initiated Total Quality Management (TQM). TQM is a revolutionary management strategy in quality assurance and cost reduction. TQM requires complete management commitment, employee involvement, and use of statistical tools. The quality engineering methods of Dr. Taguchi, employing design of experiments (DOE), is one of the most important statistical tools of TQM for designing high quality systems at reduced cost. Taguchi methods provide an efficient and systematic way to optimize designs for performance, quality, and cost. Taguchi methods have been used successfully in Japan and the United States in designing reliable, high quality products at low cost in such areas as automobiles and consumer electronics. However, these methods are just beginning to see application in the aerospace industry. The purpose of this paper is to present an overview of the Taguchi methods for improving quality and reducing cost, describe the current state of applications and its role in identifying cost sensitive design parameters.

  8. Optimal sample sizes for Welch's test under various allocation and cost considerations.

    PubMed

    Jan, Show-Li; Shieh, Gwowen

    2011-12-01

    The issue of the sample size necessary to ensure adequate statistical power has been the focus of considerableattention in scientific research. Conventional presentations of sample size determination do not consider budgetary and participant allocation scheme constraints, although there is some discussion in the literature. The introduction of additional allocation and cost concerns complicates study design, although the resulting procedure permits a practical treatment of sample size planning. This article presents exact techniques for optimizing sample size determinations in the context of Welch (Biometrika, 29, 350-362, 1938) test of the difference between two means under various design and cost considerations. The allocation schemes include cases in which (1) the ratio of group sizes is given and (2) one sample size is specified. The cost implications suggest optimally assigning subjects (1) to attain maximum power performance for a fixed cost and (2) to meet adesignated power level for the least cost. The proposed methods provide useful alternatives to the conventional procedures and can be readily implemented with the developed R and SAS programs that are available as supplemental materials from brm.psychonomic-journals.org/content/supplemental.

  9. Optimization of microchannel heat sink using genetic algorithm and Taguchi method

    NASA Astrophysics Data System (ADS)

    Singh, Bhanu Pratap; Garg, Harry; Lall, Arun K.

    2016-04-01

    Active cooling using microchannel is a challenging area. The optimization and miniaturization of the devices is increasing the heat loads and affecting the operating performance of the system. The microchannel based cooling systems are widely used and overcomes most of the limitations of the existing solutions. Microchannels help in reducing dimensions and therefore finding many important applications in the microfluidics domain. The microchannel performance is related to the geometry, material and flow conditions. Optimized selection of controllable parameters is a key issue while designing the microchannel based cooling system. The proposed work presents a simulation based study according to Taguchi design of experiment with Reynolds number, aspect ratio and plenum length as input parameters to determine SN ratio. The objective of this study is to maximize the heat transfer. Mathematical models based on these parameters were developed which helps in global optimization using Genetic Algorithm. Genetic algorithm further employed to optimize the input parameters and generates global solution points for the proposed work. It was concluded that the optimized value for heat transfer coefficient and Nusselt number was 2620.888 W/m2K and 3.4708 as compare to values obtained through SN ratio based parametric study i.e. 2601.3687 W/m2K and 3.447 respectively. Hence an error of 0.744% and 0.68% was detected in heat transfer coefficient and Nusselt number respectively.

  10. Parametric optimization of an irreversible magnetic Ericsson refrigerator with finite heat reservoirs

    NASA Astrophysics Data System (ADS)

    Ye, X. M.; Lin, G. X.; Chen, J. C.; Brück, E.

    2007-04-01

    An irreversible cycle model of magnetic Ericsson refrigerators is established, in which the finite heat capacities of external heat reservoirs, heat-transfer irreversibility, inherent regenerative losses, additional regenerative losses due to thermal resistances and irreversibility inside the magnetic working substances are taken into account. On the basis of the thermodynamic equations of paramagnetic materials, the performance characteristics of the magnetic Ericsson refrigeration cycle are investigated. By using the method of the optimal control theory, the optimal equations between the cooling load and the coefficient of performance and between the cooling load and the power input are derived. Furthermore, the maximum cooling load and the corresponding coefficient of performance, the minimum power input and the optimally operating temperatures of the cyclic working substance are obtained. The optimal operating region of the magnetic Ericsson refrigerator is determined. The results obtained here are closer to the performance characteristics of practical magnetic refrigerators with finite heat reservoirs than those in literature and are helpful to the optimal design and performance improvement of magnetic Ericsson refrigerators.

  11. Optimization of hydrous ferrous sulfate dehydration by microwave heating using response surface methodology.

    PubMed

    Yu, Yan-Tao; Liu, Bing-Guo; Chen, Guo; Peng, Jin-Hui; Srinivasakannan, C

    2012-01-01

    The work relates to assessing the ability of the microwave for dehydration of large amount of waste hydrous ferrous sulfate generated from the titanium pigment process industry. The popular process optimization tool of response surface methodology with central composite design was adopted to estimate the effect of dehydration. The process variables were chosen to be power input, duration of heating and the bed thickness, while the response variable being the weight loss. An increase in all the three process variables were found to significantly increase the weight loss, while the effect of interaction among the parameters were found to be insignificant. The optimized process conditions that contribute to the maximum weight loss were identified to be a power input of 960 W, duration of heating of 14 min and bed thickness of 5 cm, resulting in a weight loss of 31.44%. The validity of the optimization process was tested with the repeat runs at optimized conditions.

  12. Computerized systems analysis and optimization of aircraft engine performance, weight, and life cycle costs

    NASA Technical Reports Server (NTRS)

    Fishbach, L. H.

    1980-01-01

    The computational techniques are described which are utilized at Lewis Research Center to determine the optimum propulsion systems for future aircraft applications and to identify system tradeoffs and technology requirements. Cycle performance, and engine weight can be calculated along with costs and installation effects as opposed to fuel consumption alone. Almost any conceivable turbine engine cycle can be studied. These computer codes are: NNEP, WATE, LIFCYC, INSTAL, and POD DRG. Examples are given to illustrate how these computer techniques can be applied to analyze and optimize propulsion system fuel consumption, weight and cost for representative types of aircraft and missions.

  13. Finite-horizon optimal investment with transaction costs: A parabolic double obstacle problem

    NASA Astrophysics Data System (ADS)

    Dai, Min; Yi, Fahuai

    This paper concerns optimal investment problem of a CRRA investor who faces proportional transaction costs and finite time horizon. From the angle of stochastic control, it is a singular control problem, whose value function is governed by a time-dependent HJB equation with gradient constraints. We reveal that the problem is equivalent to a parabolic double obstacle problem involving two free boundaries that correspond to the optimal buying and selling policies. This enables us to make use of the well-developed theory of obstacle problem to attack the problem. The C regularity of the value function is proven and the behaviors of the free boundaries are completely characterized.

  14. Developing, testing, evaluating and optimizing solar heating and cooling systems

    SciTech Connect

    Not Available

    1991-11-01

    The objective is to develop and test various integrated solar heating, cooling and domestic hot water systems, and to evaluate their performance. Systems composed of new, as well a previously tested, components are carefully integrated so that effects of new components on system performance can be clearly delineated. The SEAL-DOE program includes six tasks which have received funding for the 1991--1992 fifteen-month period. These include: (1) a project employing isothermal operation of air and liquid solar space hearing systems, (2) a project to build and test several generic solar water heaters, (3) a project that will evaluate advanced solar domestic hot water components and concepts and integrate them into solar domestic hot water systems, (4) a liquid desiccant cooling system development project, (5) a project that will perform system modeling and analysis work on solid desiccant cooling systems research, and (6) a management task. The objectives and progress in each task are described in this report. 6 figs., 2 tabs.

  15. Optimized postweld heat treatment procedures for 17-4 PH stainless steels

    SciTech Connect

    Bhaduri, A.K.; Sujith, S.; Srinivasan, G.; Gill, T.P.S.; Mannan, S.L.

    1995-05-01

    The postweld heat treatment (PWHT) procedures for 17-4 PH stainless steel weldments of matching chemistry was optimized vis-a-vis its microstructure prior to welding based on microstructural studies and room-temperature mechanical properties. The 17-4 PH stainless steel was welded in two different prior microstructural conditions (condition A and condition H 1150) and then postweld heat treated to condition H900 or condition H1150, using different heat treatment procedures. Microstructural investigations and room-temperature tensile properties were determined to study the combined effects of prior microstructural and PWHT procedures.

  16. Implementation of transmission functions for an optimized three-terminal quantum dot heat engine

    NASA Astrophysics Data System (ADS)

    Schiegg, Christian H.; Dzierzawa, Michael; Eckern, Ulrich

    2017-03-01

    We consider two modifications of a recently proposed three-terminal quantum dot heat engine. First, we investigate the necessity of the thermalization assumption, namely that electrons are always thermalized by inelastic processes when traveling across the cavity where the heat is supplied. Second, we analyze various arrangements of tunneling-coupled quantum dots in order to implement a transmission function that is superior to the Lorentzian transmission function of a single quantum dot. We show that the maximum power of the heat engine can be improved by about a factor of two, even for a small number of dots, by choosing an optimal structure.

  17. Implementation of transmission functions for an optimized three-terminal quantum dot heat engine.

    PubMed

    Schiegg, Christian H; Dzierzawa, Michael; Eckern, Ulrich

    2017-03-01

    We consider two modifications of a recently proposed three-terminal quantum dot heat engine. First, we investigate the necessity of the thermalization assumption, namely that electrons are always thermalized by inelastic processes when traveling across the cavity where the heat is supplied. Second, we analyze various arrangements of tunneling-coupled quantum dots in order to implement a transmission function that is superior to the Lorentzian transmission function of a single quantum dot. We show that the maximum power of the heat engine can be improved by about a factor of two, even for a small number of dots, by choosing an optimal structure.

  18. Study, optimization, and design of a laser heat engine. [for satellite applications

    NASA Technical Reports Server (NTRS)

    Taussig, R. T.; Cassady, P. E.; Zumdieck, J. F.

    1978-01-01

    Laser heat engine concepts, proposed for satellite applications, are analyzed to determine which engine concept best meets the requirements of high efficiency (50 percent or better), continuous operation in space using near-term technology. The analysis of laser heat engines includes the thermodynamic cycles, engine design, laser power sources, collector/concentrator optics, receiving windows, absorbers, working fluids, electricity generation, and heat rejection. Specific engine concepts, optimized according to thermal efficiency, are rated by their technological availability and scaling to higher powers. A near-term experimental demonstration of the laser heat engine concept appears feasible utilizing an Otto cycle powered by CO2 laser radiation coupled into the engine through a diamond window. Higher cycle temperatures, higher efficiencies, and scalability to larger sizes appear to be achievable from a laser heat engine design based on the Brayton cycle and powered by a CO laser.

  19. Optimization of Insertion Cost for Transfer Trajectories to Libration Point Orbits

    NASA Technical Reports Server (NTRS)

    Howell, K. C.; Wilson, R. S.; Lo, M. W.

    1999-01-01

    The objective of this work is the development of efficient techniques to optimize the cost associated with transfer trajectories to libration point orbits in the Sun-Earth-Moon four body problem, that may include lunar gravity assists. Initially, dynamical systems theory is used to determine invariant manifolds associated with the desired libration point orbit. These manifolds are employed to produce an initial approximation to the transfer trajectory. Specific trajectory requirements such as, transfer injection constraints, inclusion of phasing loops, and targeting of a specified state on the manifold are then incorporated into the design of the transfer trajectory. A two level differential corrections process is used to produce a fully continuous trajectory that satisfies the design constraints, and includes appropriate lunar and solar gravitational models. Based on this methodology, and using the manifold structure from dynamical systems theory, a technique is presented to optimize the cost associated with insertion onto a specified libration point orbit.

  20. Cost optimization for series-parallel execution of a collection of intersecting operation sets

    NASA Astrophysics Data System (ADS)

    Dolgui, Alexandre; Levin, Genrikh; Rozin, Boris; Kasabutski, Igor

    2016-05-01

    A collection of intersecting sets of operations is considered. These sets of operations are performed successively. The operations of each set are activated simultaneously. Operation durations can be modified. The cost of each operation decreases with the increase in operation duration. In contrast, the additional expenses for each set of operations are proportional to its time. The problem of selecting the durations of all operations that minimize the total cost under constraint on completion time for the whole collection of operation sets is studied. The mathematical model and method to solve this problem are presented. The proposed method is based on a combination of Lagrangian relaxation and dynamic programming. The results of numerical experiments that illustrate the performance of the proposed method are presented. This approach was used for optimization multi-spindle machines and machining lines, but the problem is common in engineering optimization and thus the techniques developed could be useful for other applications.

  1. Optimal control and cost effectiveness analysis for Newcastle disease eco-epidemiological model in Tanzania.

    PubMed

    Hugo, Alfred; Makinde, Oluwole Daniel; Kumar, Santosh; Chibwana, Fred F

    2017-12-01

    In this paper, a deterministic compartmental eco- epidemiological model with optimal control of Newcastle disease (ND) in Tanzania is proposed and analysed. Necessary conditions of optimal control problem were rigorously analysed using Pontryagin's maximum principle and the numerical values of model parameters were estimated using maximum likelihood estimator. Three control strategies were incorporated such as chicken vaccination (preventive), human education campaign and treatment of infected human (curative) and its' impact were graphically observed. The incremental cost effectiveness analysis technique used to determine the most cost effectiveness strategy and we observe that combination of chicken vaccination and human education campaign strategy is the best strategy to implement in limited resources. Therefore, ND can be controlled if the farmers will apply chicken vaccination properly and well in time.

  2. Water network cost optimization in a paper mill based on a new library of mathematical models.

    PubMed

    Lizarralde, I; Claeys, F; Ordóñez, R; de Gracia, M; Sancho, L; Grau, P

    2012-01-01

    The increasing costs associated with water supply and the disposal of wastewater has stimulated industries to seek more efficient water management systems. Mathematical modelling and simulation can be a very valuable tool for the study of the multiple alternatives available whilst assessing optimum solutions for water management in industry. This study introduces a new steady state model library able to reproduce industrial water circuits. It has been implemented in a novel software framework for the representation, simulation and optimization of industrial water networks. A water circuit representing a paper mill has been modelled and simulated showing the capability to reproduce real case studies. Alternative scenarios for the water network have also been tested to assess the capability of the models to optimize water circuits minimizing total cost.

  3. Affordable Design: A Methodolgy to Implement Process-Based Manufacturing Cost into the Traditional Performance-Focused Multidisciplinary Design Optimization

    NASA Technical Reports Server (NTRS)

    Bao, Han P.; Samareh, J. A.

    2000-01-01

    The primary objective of this paper is to demonstrate the use of process-based manufacturing and assembly cost models in a traditional performance-focused multidisciplinary design and optimization process. The use of automated cost-performance analysis is an enabling technology that could bring realistic processbased manufacturing and assembly cost into multidisciplinary design and optimization. In this paper, we present a new methodology for incorporating process costing into a standard multidisciplinary design optimization process. Material, manufacturing processes, and assembly processes costs then could be used as the objective function for the optimization method. A case study involving forty-six different configurations of a simple wing is presented, indicating that a design based on performance criteria alone may not necessarily be the most affordable as far as manufacturing and assembly cost is concerned.

  4. Fermilab Central Computing Facility: Energy conservation report and mechanical systems design optimization and cost analysis study

    SciTech Connect

    Krstulovich, S.F.

    1986-11-12

    This report is developed as part of the Fermilab Central Computing Facility Project Title II Design Documentation Update under the provisions of DOE Document 6430.1, Chapter XIII-21, Section 14, paragraph a. As such, it concentrates primarily on HVAC mechanical systems design optimization and cost analysis and should be considered as a supplement to the Title I Design Report date March 1986 wherein energy related issues are discussed pertaining to building envelope and orientation as well as electrical systems design.

  5. Distributed bees algorithm parameters optimization for a cost efficient target allocation in swarms of robots.

    PubMed

    Jevtić, Aleksandar; Gutiérrez, Alvaro

    2011-01-01

    Swarms of robots can use their sensing abilities to explore unknown environments and deploy on sites of interest. In this task, a large number of robots is more effective than a single unit because of their ability to quickly cover the area. However, the coordination of large teams of robots is not an easy problem, especially when the resources for the deployment are limited. In this paper, the distributed bees algorithm (DBA), previously proposed by the authors, is optimized and applied to distributed target allocation in swarms of robots. Improved target allocation in terms of deployment cost efficiency is achieved through optimization of the DBA's control parameters by means of a genetic algorithm. Experimental results show that with the optimized set of parameters, the deployment cost measured as the average distance traveled by the robots is reduced. The cost-efficient deployment is in some cases achieved at the expense of increased robots' distribution error. Nevertheless, the proposed approach allows the swarm to adapt to the operating conditions when available resources are scarce.

  6. Distributed Bees Algorithm Parameters Optimization for a Cost Efficient Target Allocation in Swarms of Robots

    PubMed Central

    Jevtić, Aleksandar; Gutiérrez, Álvaro

    2011-01-01

    Swarms of robots can use their sensing abilities to explore unknown environments and deploy on sites of interest. In this task, a large number of robots is more effective than a single unit because of their ability to quickly cover the area. However, the coordination of large teams of robots is not an easy problem, especially when the resources for the deployment are limited. In this paper, the Distributed Bees Algorithm (DBA), previously proposed by the authors, is optimized and applied to distributed target allocation in swarms of robots. Improved target allocation in terms of deployment cost efficiency is achieved through optimization of the DBA’s control parameters by means of a Genetic Algorithm. Experimental results show that with the optimized set of parameters, the deployment cost measured as the average distance traveled by the robots is reduced. The cost-efficient deployment is in some cases achieved at the expense of increased robots’ distribution error. Nevertheless, the proposed approach allows the swarm to adapt to the operating conditions when available resources are scarce. PMID:22346677

  7. Integrated optimization of management cost of hierarchical mobile IPv6 and its performance simulation

    NASA Astrophysics Data System (ADS)

    Peng, Xue-hai; Zhang, Hong-ke; Zhang, Si-dong

    2004-04-01

    Mobile IPv6 was designed to enable an IPv6 terminal to continue communications seamlessly while changing its access to network. Decreasing communication and management cost is a key issue of the research of the Internet mobility management. Hierarchical Mobile IPv6 was proposed to reduce the number of management messages in backbone network. However, the resources consumptions inside a hierarchical domain are increased as expense according to our cost models. Based on the idea of integrated optimization, adaptive mobility management scheme (AMMS) is proposed in this paper, which decreases the total cost of delivering management messages and data payload on the viewpoint of entire network resources by selecting a suitable mobility management scheme adaptively for a mobile node. The results of simulation show that AMMS has better performance than unmixed Mobile IPv6 and Hierarchical Mobile IPv6.

  8. Thermodynamic analysis and optimization of a high temperature triple absorption heat transformer.

    PubMed

    Khamooshi, Mehrdad; Parham, Kiyan; Yari, Mortaza; Egelioglu, Fuat; Salati, Hana; Babadi, Saeed

    2014-01-01

    First law of thermodynamics has been used to analyze and optimize inclusively the performance of a triple absorption heat transformer operating with LiBr/H2O as the working pair. A thermodynamic model was developed in EES (engineering equation solver) to estimate the performance of the system in terms of the most essential parameters. The assumed parameters are the temperature of the main components, weak and strong solutions, economizers' efficiencies, and bypass ratios. The whole cycle is optimized by EES software from the viewpoint of maximizing the COP via applying the direct search method. The optimization results showed that the COP of 0.2491 is reachable by the proposed cycle.

  9. Optimal recovery of the solution of the heat equation from inaccurate data

    SciTech Connect

    Magaril-Il'yaev, G G; Osipenko, Konstantin Yu

    2009-06-30

    The problem of optimal recovery of the solution of the heat equation in the entire space at a fixed instant of time from inaccurate observations of this solution at some other instants of time is investigated. Explicit expressions for an optimal recovery method and its error are given. The solution of a similar problem with a priori information about the temperature distribution at some instants of time is also given. In all cases the optimal method uses information about at most two observations. Bibliography: 22 titles.

  10. Designing cost-effective biopharmaceutical facilities using mixed-integer optimization.

    PubMed

    Liu, Songsong; Simaria, Ana S; Farid, Suzanne S; Papageorgiou, Lazaros G

    2013-01-01

    Chromatography operations are identified as critical steps in a monoclonal antibody (mAb) purification process and can represent a significant proportion of the purification material costs. This becomes even more critical with increasing product titers that result in higher mass loads onto chromatography columns, potentially causing capacity bottlenecks. In this work, a mixed-integer nonlinear programming (MINLP) model was created and applied to an industrially relevant case study to optimize the design of a facility by determining the most cost-effective chromatography equipment sizing strategies for the production of mAbs. Furthermore, the model was extended to evaluate the ability of a fixed facility to cope with higher product titers up to 15 g/L. Examination of the characteristics of the optimal chromatography sizing strategies across different titer values enabled the identification of the maximum titer that the facility could handle using a sequence of single column chromatography steps as well as multi-column steps. The critical titer levels for different ratios of upstream to dowstream trains where multiple parallel columns per step resulted in the removal of facility bottlenecks were identified. Different facility configurations in terms of number of upstream trains were considered and the trade-off between their cost and ability to handle higher titers was analyzed. The case study insights demonstrate that the proposed modeling approach, combining MINLP models with visualization tools, is a valuable decision-support tool for the design of cost-effective facility configurations and to aid facility fit decisions. 2013.

  11. Multi-Objective Particle Swarm Optimization Approach for Cost-Based Feature Selection in Classification.

    PubMed

    Zhang, Yong; Gong, Dun-Wei; Cheng, Jian

    2017-01-01

    Feature selection is an important data-preprocessing technique in classification problems such as bioinformatics and signal processing. Generally, there are some situations where a user is interested in not only maximizing the classification performance but also minimizing the cost that may be associated with features. This kind of problem is called cost-based feature selection. However, most existing feature selection approaches treat this task as a single-objective optimization problem. This paper presents the first study of multi-objective particle swarm optimization (PSO) for cost-based feature selection problems. The task of this paper is to generate a Pareto front of nondominated solutions, that is, feature subsets, to meet different requirements of decision-makers in real-world applications. In order to enhance the search capability of the proposed algorithm, a probability-based encoding technology and an effective hybrid operator, together with the ideas of the crowding distance, the external archive, and the Pareto domination relationship, are applied to PSO. The proposed PSO-based multi-objective feature selection algorithm is compared with several multi-objective feature selection algorithms on five benchmark datasets. Experimental results show that the proposed algorithm can automatically evolve a set of nondominated solutions, and it is a highly competitive feature selection method for solving cost-based feature selection problems.

  12. Optimal pricing policies for services with consideration of facility maintenance costs

    NASA Astrophysics Data System (ADS)

    Yeh, Ruey Huei; Lin, Yi-Fang

    2012-06-01

    For survival and success, pricing is an essential issue for service firms. This article deals with the pricing strategies for services with substantial facility maintenance costs. For this purpose, a mathematical framework that incorporates service demand and facility deterioration is proposed to address the problem. The facility and customers constitute a service system driven by Poisson arrivals and exponential service times. A service demand with increasing price elasticity and a facility lifetime with strictly increasing failure rate are also adopted in modelling. By examining the bidirectional relationship between customer demand and facility deterioration in the profit model, the pricing policies of the service are investigated. Then analytical conditions of customer demand and facility lifetime are derived to achieve a unique optimal pricing policy. The comparative statics properties of the optimal policy are also explored. Finally, numerical examples are presented to illustrate the effects of parameter variations on the optimal pricing policy.

  13. Optimal design and control strategies for novel combined heat and power (CHP) fuel cell systems. Part I of II, datum design conditions and approach.

    SciTech Connect

    Colella, Whitney G.

    2010-06-01

    Energy network optimization (ENO) models identify new strategies for designing, installing, and controlling stationary combined heat and power (CHP) fuel cell systems (FCSs) with the goals of (1) minimizing electricity and heating costs for building owners and (2) reducing emissions of the primary greenhouse gas (GHG) - carbon dioxide (CO{sub 2}). A goal of this work is to employ relatively inexpensive simulation studies to discover more financially and environmentally effective approaches for installing CHP FCSs. ENO models quantify the impact of different choices made by power generation operators, FCS manufacturers, building owners, and governments with respect to two primary goals - energy cost savings for building owners and CO{sub 2} emission reductions. These types of models are crucial for identifying cost and CO{sub 2} optima for particular installations. Optimal strategies change with varying economic and environmental conditions, FCS performance, the characteristics of building demand for electricity and heat, and many other factors. ENO models evaluate both 'business-as-usual' and novel FCS operating strategies. For the scenarios examined here, relative to a base case of no FCSs installed, model results indicate that novel strategies could reduce building energy costs by 25% and CO{sub 2} emissions by 80%. Part I of II articles discusses model assumptions and methodology. Part II of II articles illustrates model results for a university campus town and generalizes these results for diverse communities.

  14. Time, entropy generation, and optimization in low-dissipation heat devices

    NASA Astrophysics Data System (ADS)

    Calvo Hernández, A.; Medina, A.; Roco, J. M. M.

    2015-07-01

    We present new results obtained from the Carnot-like low-dissipation model of heat devices when size- and time-constraints are taken into account, in particular those obtained from the total cycle time and the contact times of the working system with the external heat reservoirs. The influence of these constraints and of the characteristic time scale of the model on the entropy generation allows for a clear and unified interpretation of different energetic properties for both heat engines and refrigerators (REs). Some conceptual subtleties with regard to different optimization criteria, especially for REs, are discussed. So, the different status of power input, cooling power, and the unified figure of merit χ are analyzed on the basis of their absolute or local role as optimization criteria.

  15. Optimization of cryogenic and heat removal system of space borne magnets

    NASA Astrophysics Data System (ADS)

    Musicki, Z.; Hilal, M. A.; McIntosh, G. E.

    Space-based superconducting magnets require a refrigerator system to maintain operating temperature at the design value. The magnets use helium gas cooled shields and multilayer insulation. Refrigerator power is determined based on the heat leak to the shields and to the magnet winding, as well as current leads and charging losses. Electric power is supplied by a power source such as an SP-100-type reactor or solar panels. Cryogenic and heat removal system masses included in the optimization are: the insulation and shields, the refrigerator, the power supply and the heat removal panel. The system is optimized to determine the optimum radiator temperature, superinsulation thickness, helium mass flow rate and helium inlet temperature to the shields.

  16. Feet, heat and scallops: what is the cost of anthropogenic disturbance in bivalve aquaculture?

    PubMed Central

    Halsey, Lewis G.; Chauvaud, Laurent

    2016-01-01

    The effects of unnatural disturbances on the behaviour and energetics of animals are an important issue for conservation and commercial animal production. Biologging enables estimation of the energy costs of these disturbances, but not specifically the effect these costs have on growth; a key outcome measure for animal farming enterprises. We looked at how natural and anthropogenically induced activity and energy expenditure of king scallops Pecten maximus varies with temperature. These data were then used to model growth time of king scallops reared in an aquaculture facility under different temperatures and anthropogenic disturbance levels. The scallops exhibited a typical total metabolic rate (MR)–temperature curve, with a peak reached at a middling temperature. The percentage of their total MR associated with spinning and swimming, behavioural responses to disturbance, was considerable. Interestingly, as temperature increased, the activity MR associated with a given level of activity decreased; a hitherto unreported relationship in any species. The model results suggest there is a trade-off in the ambient temperature that should be set by hatcheries between the optimal for scallop growth if completely undisturbed versus mitigating against the energy costs elicited by anthropogenic disturbance. Furthermore, the model indicates that this trade-off is affected by scallop size. Aquaculture facilities typically have controls to limit the impact of human activities, yet the present data indicate that hatcheries may be advised to consider whether more controls could further decrease extraneous scallop behaviours, resulting in enhanced scallop yields and improved financial margins. PMID:27069659

  17. Cost-effective river rehabilitation planning: optimizing for morphological benefits at large spatial scales.

    PubMed

    Langhans, Simone D; Hermoso, Virgilio; Linke, Simon; Bunn, Stuart E; Possingham, Hugh P

    2014-01-01

    River rehabilitation aims to protect biodiversity or restore key ecosystem services but the success rate is often low. This is seldom because of insufficient funding for rehabilitation works but because trade-offs between costs and ecological benefits of management actions are rarely incorporated in the planning, and because monitoring is often inadequate for managers to learn by doing. In this study, we demonstrate a new approach to plan cost-effective river rehabilitation at large scales. The framework is based on the use of cost functions (relationship between costs of rehabilitation and the expected ecological benefit) to optimize the spatial allocation of rehabilitation actions needed to achieve given rehabilitation goals (in our case established by the Swiss water act). To demonstrate the approach with a simple example, we link costs of the three types of management actions that are most commonly used in Switzerland (culvert removal, widening of one riverside buffer and widening of both riversides) to the improvement in riparian zone quality. We then use Marxan, a widely applied conservation planning software, to identify priority areas to implement these rehabilitation measures in two neighbouring Swiss cantons (Aargau, AG and Zürich, ZH). The best rehabilitation plans identified for the two cantons met all the targets (i.e. restoring different types of morphological deficits with different actions) rehabilitating 80,786 m (AG) and 106,036 m (ZH) of the river network at a total cost of 106.1 Million CHF (AG) and 129.3 Million CH (ZH). The best rehabilitation plan for the canton of AG consisted of more and better connected sub-catchments that were generally less expensive, compared to its neighbouring canton. The framework developed in this study can be used to inform river managers how and where best to spend their rehabilitation budget for a given set of actions, ensures the cost-effective achievement of desired rehabilitation outcomes, and helps

  18. On the use of topology optimization for improving heat transfer in molding process

    NASA Astrophysics Data System (ADS)

    Agazzi, A.; LeGoff, R.; Truc-Vu, C.

    2016-10-01

    In the plastic industry, one of the key factor is to control heat transfer. One way to achieve that goal is to design an effective cooling system. But in some area of the mold, where it is not possible to design cooling system, the use of a highly conductive material, such as copper pin, is often used. Most of the time, the location, the size and the quantity of the copper pin are made by empirical considerations, without using optimization procedures. In this article, it is proposed to use topology optimization, in order to improve transient conductive heat transfer in an injection/blowing mold. Two methodologies are applied and compared. Finally, the optimal distribution of cooper pin in the mold is given.

  19. Impact of Coverage-Dependent Marginal Costs on Optimal HPV Vaccination Strategies

    PubMed Central

    Ryser, Marc D.; McGoff, Kevin; Herzog, David P.; Sivakoff, David J.; Myers, Evan R.

    2015-01-01

    The effectiveness of vaccinating males against the human papillomavirus (HPV) remains a controversial subject. Many existing studies conclude that increasing female coverage is more effective than diverting resources into male vaccination. Recently, several empirical studies on HPV immunization have been published, providing evidence of the fact that marginal vaccination costs increase with coverage. In this study, we use a stochastic agent-based modeling framework to revisit the male vaccination debate in light of these new findings. Within this framework, we assess the impact of coverage-dependent marginal costs of vaccine distribution on optimal immunization strategies against HPV. Focusing on the two scenarios of ongoing and new vaccination programs, we analyze different resource allocation policies and their effects on overall disease burden. Our results suggest that if the costs associated with vaccinating males are relatively close to those associated with vaccinating females, then coverage-dependent, increasing marginal costs may favor vaccination strategies that entail immunization of both genders. In particular, this study emphasizes the necessity for further empirical research on the nature of coverage-dependent vaccination costs. PMID:25979280

  20. Impact of coverage-dependent marginal costs on optimal HPV vaccination strategies.

    PubMed

    Ryser, Marc D; McGoff, Kevin; Herzog, David P; Sivakoff, David J; Myers, Evan R

    2015-06-01

    The effectiveness of vaccinating males against the human papillomavirus (HPV) remains a controversial subject. Many existing studies conclude that increasing female coverage is more effective than diverting resources into male vaccination. Recently, several empirical studies on HPV immunization have been published, providing evidence of the fact that marginal vaccination costs increase with coverage. In this study, we use a stochastic agent-based modeling framework to revisit the male vaccination debate in light of these new findings. Within this framework, we assess the impact of coverage-dependent marginal costs of vaccine distribution on optimal immunization strategies against HPV. Focusing on the two scenarios of ongoing and new vaccination programs, we analyze different resource allocation policies and their effects on overall disease burden. Our results suggest that if the costs associated with vaccinating males are relatively close to those associated with vaccinating females, then coverage-dependent, increasing marginal costs may favor vaccination strategies that entail immunization of both genders. In particular, this study emphasizes the necessity for further empirical research on the nature of coverage-dependent vaccination costs.

  1. Energy and Cost Optimized Technology Options to Meet Energy Needs of Food Processors

    SciTech Connect

    Makhmalbaf, Atefe; Srivastava, Viraj; Hoffman, Michael G.; Wagner, Anne W.; Thornton, John

    2015-04-02

    ABSTRACT Combined cooling, heating and electric power (CCHP) distributed generation (DG) systems can provide electricity, heat, and cooling power to buildings and industrial processes directly onsite, while significantly increasing energy efficiency, security of energy supply, and grid independence. Fruit, vegetable, dairy and meat processing industries with simultaneous requirements for heat, steam, chilling and electricity, are well suited for the use of such systems to supply base-load electrical demand or as peak reducing generators with heat recovery in the forms of hot water, steam and/or chilled water. This paper documents results and analysis from a pilot project to evaluate opportunities for energy, emission, and cost for CCHP-DG and energy storage systems installed onsite at food processing facilities. It was found that a dairy processing plant purchasing 15,000 MWh of electricity will need to purchase 450 MWh with the integration of a 1.1 MW CCHP system. Here, the natural gas to be purchased increased from 190,000 MMBtu to 255,000 MMBtu given the fuel requirements of the CCHP system. CCHP systems lower emissions, however, in the Pacific Northwest the high percentage of hydro-power results in CO2 emissions from CCHP were higher than that attributed to the electric utility/regional energy mix. The value of this paper is in promoting and educating financial decision makers to seriously consider CCHP systems when building or upgrading facilities. The distributed generation aspect can reduce utility costs for industrial facilities and show non-wires solution benefits to delay or eliminate the need for upgrades to local electric transmission and distribution systems.

  2. Optimization and stabilization of gold nanoparticles by using herbal plant extract with microwave heating

    NASA Astrophysics Data System (ADS)

    Yasmin, Akbar; Ramesh, Kumaraswamy; Rajeshkumar, Shanmugam

    2014-04-01

    In this study, we have synthesized the gold nanoparticles by using Hibiscus rosa-sinensis, a medicinal plant. The gold nanoparticles were synthesized rapidly by the involvement of microwave heating. By changing of plant extract concentration, gold solution concentration, microwave heating time and power of microwave heating the optimized condition was identified. The surface Plasmon resonance found at 520 nm confirmed the gold nanoparticles synthesis. The spherical sized nanoparticles in the size range of 16-30 nm were confirmed by Transmission Electron Microscope (TEM). The stability of the nanoparticles is very well proved in the invitro stability tests. The biochemical like alkaloids and flavonoids play a vital role in the nanoparticles synthesis was identified using the Fourier Transform Infrared Spectroscopy (FTIR). Combining the phytochemical and microwave heating, the rapid synthesis of gold nanoparticles is the novel process for the medically applicable gold nanoparticles production.

  3. Life span and reproductive cost explain interspecific variation in the optimal onset of reproduction.

    PubMed

    Mourocq, Emeline; Bize, Pierre; Bouwhuis, Sandra; Bradley, Russell; Charmantier, Anne; de la Cruz, Carlos; Drobniak, Szymon M; Espie, Richard H M; Herényi, Márton; Hötker, Hermann; Krüger, Oliver; Marzluff, John; Møller, Anders P; Nakagawa, Shinichi; Phillips, Richard A; Radford, Andrew N; Roulin, Alexandre; Török, János; Valencia, Juliana; van de Pol, Martijn; Warkentin, Ian G; Winney, Isabel S; Wood, Andrew G; Griesser, Michael

    2016-02-01

    Fitness can be profoundly influenced by the age at first reproduction (AFR), but to date the AFR-fitness relationship only has been investigated intraspecifically. Here, we investigated the relationship between AFR and average lifetime reproductive success (LRS) across 34 bird species. We assessed differences in the deviation of the Optimal AFR (i.e., the species-specific AFR associated with the highest LRS) from the age at sexual maturity, considering potential effects of life history as well as social and ecological factors. Most individuals adopted the species-specific Optimal AFR and both the mean and Optimal AFR of species correlated positively with life span. Interspecific deviations of the Optimal AFR were associated with indices reflecting a change in LRS or survival as a function of AFR: a delayed AFR was beneficial in species where early AFR was associated with a decrease in subsequent survival or reproductive output. Overall, our results suggest that a delayed onset of reproduction beyond maturity is an optimal strategy explained by a long life span and costs of early reproduction. By providing the first empirical confirmations of key predictions of life-history theory across species, this study contributes to a better understanding of life-history evolution.

  4. Instantaneous Metabolic Cost of Walking: Joint-Space Dynamic Model with Subject-Specific Heat Rate

    PubMed Central

    Roberts, Dustyn; Hillstrom, Howard; Kim, Joo H.

    2016-01-01

    A subject-specific model of instantaneous cost of transport (ICOT) is introduced from the joint-space formulation of metabolic energy expenditure using the laws of thermodynamics and the principles of multibody system dynamics. Work and heat are formulated in generalized coordinates as functions of joint kinematic and dynamic variables. Generalized heat rates mapped from muscle energetics are estimated from experimental walking metabolic data for the whole body, including upper-body and bilateral data synchronization. Identified subject-specific energetic parameters—mass, height, (estimated) maximum oxygen uptake, and (estimated) maximum joint torques—are incorporated into the heat rate, as opposed to the traditional in vitro and subject-invariant muscle parameters. The total model metabolic energy expenditure values are within 5.7 ± 4.6% error of the measured values with strong (R2 > 0.90) inter- and intra-subject correlations. The model reliably predicts the characteristic convexity and magnitudes (0.326–0.348) of the experimental total COT (0.311–0.358) across different subjects and speeds. The ICOT as a function of time provides insights into gait energetic causes and effects (e.g., normalized comparison and sensitivity with respect to walking speed) and phase-specific COT, which are unavailable from conventional metabolic measurements or muscle models. Using the joint-space variables from commonly measured or simulated data, the models enable real-time and phase-specific evaluations of transient or non-periodic general tasks that use a range of (aerobic) energy pathway similar to that of steady-state walking. PMID:28030598

  5. Analysis of Energy, Environmental and Life Cycle Cost Reduction Potential of Ground Source Heat Pump (GSHP) in Hot and Humid Climate

    SciTech Connect

    Yong X. Tao; Yimin Zhu

    2012-04-26

    It has been widely recognized that the energy saving benefits of GSHP systems are best realized in the northern and central regions where heating needs are dominant or both heating and cooling loads are comparable. For hot and humid climate such as in the states of FL, LA, TX, southern AL, MS, GA, NC and SC, buildings have much larger cooling needs than heating needs. The Hybrid GSHP (HGSHP) systems therefore have been developed and installed in some locations of those states, which use additional heat sinks (such as cooling tower, domestic water heating systems) to reject excess heat. Despite the development of HGSHP the comprehensive analysis of their benefits and barriers for wide application has been limited and often yields non-conclusive results. In general, GSHP/HGSHP systems often have higher initial costs than conventional systems making short-term economics unattractive. Addressing these technical and financial barriers call for additional evaluation of innovative utility programs, incentives and delivery approaches. From scientific and technical point of view, the potential for wide applications of GSHP especially HGSHP in hot and humid climate is significant, especially towards building zero energy homes where the combined energy efficient GSHP and abundant solar energy production in hot climate can be an optimal solution. To address these challenges, this report presents gathering and analyzing data on the costs and benefits of GSHP/HGSHP systems utilized in southern states using a representative sample of building applications. The report outlines the detailed analysis to conclude that the application of GSHP in Florida (and hot and humid climate in general) shows a good potential.

  6. Design Optimization and the Limits of Steady-State Heating Efficiency for Conventional Single-Speed Air-Source Heat Pumps

    SciTech Connect

    Rice, C.K.

    2001-06-06

    The ORNL Heat Pump Model and an optimizing program were used to explore the limits of steady-state heating efficiency for conventional air-source heat pumps. The method used allows for the simultaneous optimization of ten selected design variables, taking proper account of their interactions, while constraining other parameters to chosen limits or fixed values. Designs were optimized for a fixed heating capacity, but the results may be scaled to other capacities. Substantial performance improvement is predicted compared to today's state of the art heat pump. With increased component efficiencies that are expected in the near future and with modest increases in heat exchanger area, a 28% increase in heating efficiency is predicted; for long-term improvements with considerably larger heat exchangers, a 56% increase is possible. The improved efficiencies are accompanied by substantial reductions in the requirements for compressor and motor size. The predicted performance improvements are attributed not only to improved components and larger heat exchangers but also to the use of an optimizing design procedure. Deviations from the optimized design may be necessary to make use of available component sizes and to maintain good cooling-mode performance while improving the heating efficiency. Sensitivity plots (i.e., COP as a function of one or more design parameters) were developed to explore design flexibilities and to evaluate their consequences. The performance of the optimized designs was compared to that of modified ideal cycles to assess the factors that limit further improvement. It is hoped that the design methods developed will be useful to designers in the heat pump industry.

  7. Split radiator design for heat rejection optimization for a waste heat recovery system

    DOEpatents

    Ernst, Timothy C.; Nelson, Christopher R.

    2016-10-18

    A cooling system provides improved heat recovery by providing a split core radiator for both engine cooling and condenser cooling for a Rankine cycle (RC). The cooling system includes a radiator having a first cooling core portion and a second cooling core portion. An engine cooling loop is fluidly connected the second cooling core portion. A condenser of an RC has a cooling loop fluidly connected to the first cooling core portion. A valve is provided between the engine cooling loop and the condenser cooling loop adjustably control the flow of coolant in the condenser cooling loop into the engine cooling loop. The cooling system includes a controller communicatively coupled to the valve and adapted to determine a load requirement for the internal combustion engine and adjust the valve in accordance with the engine load requirement.

  8. Optimal allocation and effectiveness of the heat exchangers for a power plant with two like-Carnot cycles

    NASA Astrophysics Data System (ADS)

    Aragón-González, G.; León-Galicia, A.

    2017-01-01

    A stationary power plant with two Carnot-like cycles is optimized. Each cycle has the following irreversibilities: finite rate heat transfer between the working fluid and the external heat sources, internal dissipation of the working fluid, and heat leak between reservoirs; is extended to two or more of this combined model. Using the Bellman’ Principle, we find the optimal recurrence relations for the allocation of the heat exchangers for this power plant. The optimal allocation or effectiveness of the heat exganchers of power plant is determined by two design rules: internal thermal conductance fixed; or areas fixed. The optimal obtained are invariant to the power and efficiency and to the heat transfer law.

  9. Unified trade-off optimization for general heat devices with nonisothermal processes

    NASA Astrophysics Data System (ADS)

    Long, Rui; Liu, Wei

    2015-04-01

    An analysis of the efficiency and coefficient of performance (COP) for general heat engines and refrigerators with nonisothermal processes is conducted under the trade-off criterion. The specific heat of the working medium has significant impacts on the optimal configurations of heat devices. For cycles with constant specific heat, the bounds of the efficiency and COP are found to be the same as those obtained through the endoreversible Carnot ones. However, they are independent of the cycle time durations. For cycles with nonconstant specific heat, whose dimensionless contact time approaches infinity, the general alternative upper and lower bounds of the efficiency and COP under the trade-off criteria have been proposed under the asymmetric limits. Furthermore, when the dimensionless contact time approaches zero, the endoreversible Carnot model is recovered. In addition, the efficiency and COP bounds of different kinds of actual heat engines and refrigerators have also been analyzed. This paper may provide practical insight for designing and operating actual heat engines and refrigerators.

  10. Bioregenerative food system cost based on optimized menus for advanced life support

    NASA Technical Reports Server (NTRS)

    Waters, Geoffrey C R.; Olabi, Ammar; Hunter, Jean B.; Dixon, Mike A.; Lasseur, Christophe

    2002-01-01

    Optimized menus for a bioregenerative life support system have been developed based on measures of crop productivity, food item acceptability, menu diversity, and nutritional requirements of crew. Crop-specific biomass requirements were calculated from menu recipe demands while accounting for food processing and preparation losses. Under the assumption of staggered planting, the optimized menu demanded a total crop production area of 453 m2 for six crew. Cost of the bioregenerative food system is estimated at 439 kg per menu cycle or 7.3 kg ESM crew-1 day-1, including agricultural waste processing costs. On average, about 60% (263.6 kg ESM) of the food system cost is tied up in equipment, 26% (114.2 kg ESM) in labor, and 14% (61.5 kg ESM) in power and cooling. This number is high compared to the STS and ISS (nonregenerative) systems but reductions in ESM may be achieved through intensive crop productivity improvements, reductions in equipment masses associated with crop production, and planning of production, processing, and preparation to minimize the requirement for crew labor.

  11. Optimization of an inclined elliptic impinging jet with cross flow for enhancing heat transfer

    NASA Astrophysics Data System (ADS)

    Heo, Man-Woong; Lee, Ki-Don; Kim, Kwang-Yong

    2011-06-01

    This work presents a parametric study and optimization of a single impinging jet with cross flow to enhance heat transfer with two design variables. The fluid flow and heat transfer have been analyzed using three-dimensional compressible Reynolds-averaged Navier-Stokes equations with a uniform heat flux condition being applied to the impingement plate. The aspect ratio of the elliptic jet hole and the angle of inclination of the jet nozzle are chosen as the two design variables, and the area-averaged Nusselt number on a limited target plate is set as the objective function. The effects of the design variables on the heat transfer performance have been evaluated, and the objective function has been found to be more sensitive to the angle of inclination of the jet nozzle than to the aspect ratio of the elliptic jet hole. The optimization has been performed by using the radial basis neural network model. Through the optimization, the area-averaged Nusselt number increased by 7.89% compared to that under the reference geometry.

  12. Numerical research and optimization of convective heat transfer for multi-segment amplifiers

    NASA Astrophysics Data System (ADS)

    Ren, Zhiyuan; Zhu, Jianqiang; Huang, Hongbiao; Liu, Zhigang

    2013-04-01

    Optimized convective heat transfer is applied to accelerate the thermal recovery of a large aperture multi-segment amplifier. The paper proposes a novel project of changing the structural parameters of the inlet jet to the Nd:glass slab in the multi-segment amplifier at the same flow rate. The convective heat transfer coefficient depends on the diameter of the inlet jet, as well as on the number of inlet jets. The simulation calculations indicate that at the same flow rate, different numbers of inlet jet lead to different temperature gradient contours and flow field distributions on the Nd:glass slab surface in the multi-segment amplifier. In addition, the convective heat transfer coefficient increases with the decrease of inlet diameter. This work analyzes the path of the coolant air over the slab surface to lessen the eddy and to achieve better convective heat transfer, as well as to determine the optimized number of inlet jets (5) and the optimized diameter (5 mm).

  13. Learning Near-Optimal Cost-Sensitive Decision Policy for Object Detection.

    PubMed

    Wu, Tianfu; Zhu, Song-Chun

    2015-05-01

    Many popular object detectors, such as AdaBoost, SVM and deformable part-based models (DPM), compute additive scoring functions at a large number of windows in an image pyramid, thus computational efficiency is an important consideration in real time applications besides accuracy. In this paper, a decision policy refers to a sequence of two-sided thresholds to execute early reject and early accept based on the cumulative scores at each step. We formulate an empirical risk function as the weighted sum of the cost of computation and the loss of false alarm and missing detection. Then a policy is said to be cost-sensitive and optimal if it minimizes the risk function. While the risk function is complex due to high-order correlations among the two-sided thresholds, we find that its upper bound can be optimized by dynamic programming efficiently. We show that the upper bound is very tight empirically and thus the resulting policy is said to be near-optimal. In experiments, we show that the decision policy outperforms state-of-the-art cascade methods significantly, in several popular detection tasks and benchmarks, in terms of computational efficiency with similar accuracy of detection.

  14. Optimal heating trajectories of controlling green tapes of YSZ electrolyte deformation using TMA during thermal processing

    NASA Astrophysics Data System (ADS)

    Liau, Leo Chau-Kuang; Chen, Chung-Chun

    The optimal heating trajectories to minimize the time required for the organic additives removal in yttria-stabilized zirconia (YSZ) green tapes were determined using a dynamic optimization method. The removal process model was described by the mass transport of the volatile gas evolved from the thermal decomposition of the organic additives inside the tapes and the kinetics of the decomposition. The pressure buildup of the sample tapes formed by the volatile gas can be estimated by a numerical simulation method; meanwhile, the deformation (strain) of the tape caused by the pressure buildup was measured by a thermal mechanical analyzer (TMA) during the thermal processing. Results show that the formation of the maximum pressure buildup at the center of the cubic tape is influenced by the sample size and heating conditions. In addition, the dynamic strain at the center of the sample measured by TMA agrees with the formation of the pressure buildup estimated by the numerical calculation. Moreover, the optimal heating trajectories determined by the dynamic optimization scheme with the constraint of the formation of the maximum pressure buildup were verified from the tape deformation analysis by the TMA tests.

  15. Simulation and optimization of a pulsating heat pipe using artificial neural network and genetic algorithm

    NASA Astrophysics Data System (ADS)

    Jokar, Ali; Godarzi, Ali Abbasi; Saber, Mohammad; Shafii, Mohammad Behshad

    2016-11-01

    In this paper, a novel approach has been presented to simulate and optimize the pulsating heat pipes (PHPs). The used pulsating heat pipe setup was designed and constructed for this study. Due to the lack of a general mathematical model for exact analysis of the PHPs, a method has been applied for simulation and optimization using the natural algorithms. In this way, the simulator consists of a kind of multilayer perceptron neural network, which is trained by experimental results obtained from our PHP setup. The results show that the complex behavior of PHPs can be successfully described by the non-linear structure of this simulator. The input variables of the neural network are input heat flux to evaporator (q″), filling ratio (FR) and inclined angle (IA) and its output is thermal resistance of PHP. Finally, based upon the simulation results and considering the heat pipe's operating constraints, the optimum operating point of the system is obtained by using genetic algorithm (GA). The experimental results show that the optimum FR (38.25 %), input heat flux to evaporator (39.93 W) and IA (55°) that obtained from GA are acceptable.

  16. Impact of overall and particle surface heat transfer coefficients on thermal process optimization in rotary retorts.

    PubMed

    Simpson, R; Abakarov, A; Almonacid, S; Teixeira, A

    2008-10-01

    This study attempts to examine the significance of recent research that has focused on efforts to estimate values for global and surface heat transfer coefficients under forced convection heating induced by end-over-end rotation in retorting of canned peas in brine. The study confirms the accuracy of regression analysis used to predict values for heat transfer coefficients as a function of rotating speed and headspace, and uses them to predict values over a range of process conditions, which make up the search domain for process optimization. These coefficients were used in a convective heat transfer model to establish a range of lethality-equivalent retort temperature-time processes for various conditions of retort temperature, rotating speed, and headspace. Then, they were coupled with quality factor kinetics to predict the final volume average and surface quality retention resulting from each process and to find the optimal thermal process conditions for canned fresh green peas. Results showed that maximum quality retention (surface and volume average retention) was achieved with the shortest possible process time (made possible with highest retort temperature), and reached the similar level in all cases with small difference between surface and volume average quality retention. The highest heat transfer coefficients (associated with maximum rotating speed and headspace) showed a 10% reduction in process time over that required with minimum rotating speed and headspace. The study concludes with a discussion of the significance of these findings and degree to which they were expected.

  17. Inverse problems and optimal experiment design in unsteady heat transfer processes identification

    NASA Technical Reports Server (NTRS)

    Artyukhin, Eugene A.

    1991-01-01

    Experimental-computational methods for estimating characteristics of unsteady heat transfer processes are analyzed. The methods are based on the principles of distributed parameter system identification. The theoretical basis of such methods is the numerical solution of nonlinear ill-posed inverse heat transfer problems and optimal experiment design problems. Numerical techniques for solving problems are briefly reviewed. The results of the practical application of identification methods are demonstrated when estimating effective thermophysical characteristics of composite materials and thermal contact resistance in two-layer systems.

  18. Optimal space-time coverage and exploration costs in groundwater monitoring networks.

    PubMed

    Nunes, L M; Cunha, M C; Ribeiro, L

    2004-01-01

    A method to determine the optimal subset of stations from a reference level groundwater monitoring network is proposed. The method considers the redundancy of data from historical time series, the times associated with the total distance required to run through the entire monitoring network, and the sum of the times for each monitoring station. The method was applied to a hypothetical case-study consisting of a monitoring network with 32 stations. Cost-benefit analysis was performed to determine the number of stations to include in the new design versus loss of information. This optimisation problem was solved with simulated annealing. Results showed that the relative reduction in exploration costs more than compensates for the relative loss in data representativeness.

  19. Optimization and cost estimation of novel wheat biorefining for continuous production of fermentation feedstock.

    PubMed

    Arifeen, Najmul; Wang, Ruohang; Kookos, Ioannis; Webb, Colin; Koutinas, Apostolis A

    2007-01-01

    A wheat-based continuous process for the production of a nutrient-complete feedstock for bioethanol production by yeast fermentation has been cost-optimized. This process could substitute for the current wheat dry milling process employed in industry for bioethanol production. Each major wheat component (bran, gluten, starch) is extracted and processed for different end-uses. The separate stages, liquefaction and saccharification, used currently in industry for starch hydrolysis have been integrated into a simplified continuous process by exploiting the complex enzymatic consortium produced by on-site fungal bioconversions. A process producing 120 m3 h-1 nutrient-complete feedstock for bioethanol production containing 250 g L-1 glucose and 0.85 g L-1 free amino nitrogen would result in a production cost of $0.126/kg glucose.

  20. Systems and methods for energy cost optimization in a building system

    DOEpatents

    Turney, Robert D.; Wenzel, Michael J.

    2016-09-06

    Methods and systems to minimize energy cost in response to time-varying energy prices are presented for a variety of different pricing scenarios. A cascaded model predictive control system is disclosed comprising an inner controller and an outer controller. The inner controller controls power use using a derivative of a temperature setpoint and the outer controller controls temperature via a power setpoint or power deferral. An optimization procedure is used to minimize a cost function within a time horizon subject to temperature constraints, equality constraints, and demand charge constraints. Equality constraints are formulated using system model information and system state information whereas demand charge constraints are formulated using system state information and pricing information. A masking procedure is used to invalidate demand charge constraints for inactive pricing periods including peak, partial-peak, off-peak, critical-peak, and real-time.

  1. Vehicle path-planning in three dimensions using optics analogs for optimizing visibility and energy cost

    NASA Technical Reports Server (NTRS)

    Rowe, Neil C.; Lewis, David H.

    1989-01-01

    Path planning is an important issue for space robotics. Finding safe and energy-efficient paths in the presence of obstacles and other constraints can be complex although important. High-level (large-scale) path planning for robotic vehicles was investigated in three-dimensional space with obstacles, accounting for: (1) energy costs proportional to path length; (2) turn costs where paths change trajectory abruptly; and (3) safety costs for the danger associated with traversing a particular path due to visibility or invisibility from a fixed set of observers. Paths optimal with respect to these cost factors are found. Autonomous or semi-autonomous vehicles were considered operating either in a space environment around satellites and space platforms, or aircraft, spacecraft, or smart missiles operating just above lunar and planetary surfaces. One class of applications concerns minimizing detection, as for example determining the best way to make complex modifications to a satellite without being observed by hostile sensors; another example is verifying there are no paths (holes) through a space defense system. Another class of applications concerns maximizing detection, as finding a good trajectory between mountain ranges of a planet while staying reasonably close to the surface, or finding paths for a flight between two locations that maximize the average number of triangulation points available at any time along the path.

  2. Advanced Targeting Cost Function Design for Evolutionary Optimization of Control of Logistic Equation

    NASA Astrophysics Data System (ADS)

    Senkerik, Roman; Zelinka, Ivan; Davendra, Donald; Oplatkova, Zuzana

    2010-06-01

    This research deals with the optimization of the control of chaos by means of evolutionary algorithms. This work is aimed on an explanation of how to use evolutionary algorithms (EAs) and how to properly define the advanced targeting cost function (CF) securing very fast and precise stabilization of desired state for any initial conditions. As a model of deterministic chaotic system, the one dimensional Logistic equation was used. The evolutionary algorithm Self-Organizing Migrating Algorithm (SOMA) was used in four versions. For each version, repeated simulations were conducted to outline the effectiveness and robustness of used method and targeting CF.

  3. Life cycle cost optimization of biofuel supply chains under uncertainties based on interval linear programming.

    PubMed

    Ren, Jingzheng; Dong, Liang; Sun, Lu; Goodsite, Michael Evan; Tan, Shiyu; Dong, Lichun

    2015-01-01

    The aim of this work was to develop a model for optimizing the life cycle cost of biofuel supply chain under uncertainties. Multiple agriculture zones, multiple transportation modes for the transport of grain and biofuel, multiple biofuel plants, and multiple market centers were considered in this model, and the price of the resources, the yield of grain and the market demands were regarded as interval numbers instead of constants. An interval linear programming was developed, and a method for solving interval linear programming was presented. An illustrative case was studied by the proposed model, and the results showed that the proposed model is feasible for designing biofuel supply chain under uncertainties.

  4. Cost analysis of water and sediment diversions to optimize land building in the Mississippi River delta

    NASA Astrophysics Data System (ADS)

    Kenney, Melissa A.; Hobbs, Benjamin F.; Mohrig, David; Huang, Hongtai; Nittrouer, Jeffrey A.; Kim, Wonsuck; Parker, Gary

    2013-06-01

    Land loss in the Mississippi River delta caused by subsidence and erosion has resulted in habitat loss and increased exposure of settled areas to storm surge risks. There is debate over the most cost-efficient and geomorphologically feasible projects to build land by river diversions, namely, whether a larger number of small, or a lesser number of large, engineered diversions provide the most efficient outcomes. This study uses an optimization framework to identify portfolios of diversions that are efficient for three general restoration objectives: maximize land built, minimize cost, and minimize water diverted. The framework links the following models: (1) a hydraulic water and sediment diversion model that, for a given structural design for a diversion, estimates the volume of water and sediment diverted; (2) a geomorphological land-building model that estimates the amount of land built over a time period, given the volume of water and sediment; and (3) a statistical model of investment cost as a function of diversion depth and width. An efficient portfolio is found by optimizing one objective subject to constraints on achievement of the other two; then by permuting those constraints, we find distinct portfolios that represent trade-offs among the objectives. Although the analysis explores generic relationships among size, cost, and land building (and thus does not consider specific project proposals or locations), the results demonstrate that large-scale land building (>200 km2) programs that operate over a time span of 50 years require deep diversions because of the enhanced efficiency of sand extraction per unit water. This conclusion applies whether or not there are significant scale economies or diseconomies associated with wider and deeper diversions.

  5. Determining the optimal approach to improving trauma triage decisions: a cost-effectiveness analysis

    PubMed Central

    Mohan, Deepika; Barnato, Amber E; Rosengart, Matthew R; Angus, Derek C; Smith, Kenneth J

    2013-01-01

    Objective To identify the optimal target of a future intervention to improve physician decision making in trauma triage. Study Design A comparison of the incremental cost-effectiveness ratios (ICERs) of current practice versus hypothetical interventions targeting either physicians’ decisional thresholds (attitudes towards transferring patients to trauma centers) or perceptual sensitivity (ability to identify patients who meet guidelines for transfer). Methods Taking the societal perspective, we constructed a Markov decision model. We drew estimates of triage patterns, mortality, utilities, and costs from the literature. We assumed that an intervention to change decisional threshold would reduce under-triage but also increase over-triage more than an intervention to change perceptual sensitivity. We performed a series of one-way sensitivity analyses, and studied the most influential variables in a Monte Carlo simulation. Results The ICER of an intervention to change perceptual sensitivity was $62,799/ quality-adjusted life years (QALY)-gained compared with current practice. The ICER of an intervention to change decisional threshold was $104,975/QALY-gained compared with an intervention to change perceptual sensitivity. These findings were most sensitive to the relative cost of hospitalizing patients with moderate-severe injuries and their relative risk of dying at non-trauma centers. In probabilistic sensitivity analyses, at a willingness-to-pay threshold of $100,000/QALY-gained, there was a 62% likelihood that an intervention to change perceptual sensitivity was the most cost-effective alternative. Conclusions Even a minor investment in changing decision making in trauma triage could greatly improve the quality of care provided. The optimal intervention depends on the characteristics of the individual trauma systems. PMID:22435966

  6. Optimal combinations of control strategies and cost-effective analysis for visceral leishmaniasis disease transmission

    PubMed Central

    Biswas, Santanu; Subramanian, Abhishek; ELMojtaba, Ibrahim M.; Chattopadhyay, Joydev; Sarkar, Ram Rup

    2017-01-01

    Visceral leishmaniasis (VL) is a deadly neglected tropical disease that poses a serious problem in various countries all over the world. Implementation of various intervention strategies fail in controlling the spread of this disease due to issues of parasite drug resistance and resistance of sandfly vectors to insecticide sprays. Due to this, policy makers need to develop novel strategies or resort to a combination of multiple intervention strategies to control the spread of the disease. To address this issue, we propose an extensive SIR-type model for anthroponotic visceral leishmaniasis transmission with seasonal fluctuations modeled in the form of periodic sandfly biting rate. Fitting the model for real data reported in South Sudan, we estimate the model parameters and compare the model predictions with known VL cases. Using optimal control theory, we study the effects of popular control strategies namely, drug-based treatment of symptomatic and PKDL-infected individuals, insecticide treated bednets and spray of insecticides on the dynamics of infected human and vector populations. We propose that the strategies remain ineffective in curbing the disease individually, as opposed to the use of optimal combinations of the mentioned strategies. Testing the model for different optimal combinations while considering periodic seasonal fluctuations, we find that the optimal combination of treatment of individuals and insecticide sprays perform well in controlling the disease for the time period of intervention introduced. Performing a cost-effective analysis we identify that the same strategy also proves to be efficacious and cost-effective. Finally, we suggest that our model would be helpful for policy makers to predict the best intervention strategies for specific time periods and their appropriate implementation for elimination of visceral leishmaniasis. PMID:28222162

  7. Optimal combinations of control strategies and cost-effective analysis for visceral leishmaniasis disease transmission.

    PubMed

    Biswas, Santanu; Subramanian, Abhishek; ELMojtaba, Ibrahim M; Chattopadhyay, Joydev; Sarkar, Ram Rup

    2017-01-01

    Visceral leishmaniasis (VL) is a deadly neglected tropical disease that poses a serious problem in various countries all over the world. Implementation of various intervention strategies fail in controlling the spread of this disease due to issues of parasite drug resistance and resistance of sandfly vectors to insecticide sprays. Due to this, policy makers need to develop novel strategies or resort to a combination of multiple intervention strategies to control the spread of the disease. To address this issue, we propose an extensive SIR-type model for anthroponotic visceral leishmaniasis transmission with seasonal fluctuations modeled in the form of periodic sandfly biting rate. Fitting the model for real data reported in South Sudan, we estimate the model parameters and compare the model predictions with known VL cases. Using optimal control theory, we study the effects of popular control strategies namely, drug-based treatment of symptomatic and PKDL-infected individuals, insecticide treated bednets and spray of insecticides on the dynamics of infected human and vector populations. We propose that the strategies remain ineffective in curbing the disease individually, as opposed to the use of optimal combinations of the mentioned strategies. Testing the model for different optimal combinations while considering periodic seasonal fluctuations, we find that the optimal combination of treatment of individuals and insecticide sprays perform well in controlling the disease for the time period of intervention introduced. Performing a cost-effective analysis we identify that the same strategy also proves to be efficacious and cost-effective. Finally, we suggest that our model would be helpful for policy makers to predict the best intervention strategies for specific time periods and their appropriate implementation for elimination of visceral leishmaniasis.

  8. Break-Even Cost for Residential Solar Water Heating in the United States: Key Drivers and Sensitivities

    SciTech Connect

    Cassard, H.; Denholm, P.; Ong, S.

    2011-02-01

    This paper examines the break-even cost for residential rooftop solar water heating (SWH) technology, defined as the point where the cost of the energy saved with a SWH system equals the cost of a conventional heating fuel purchased from the grid (either electricity or natural gas). We examine the break-even cost for the largest 1,000 electric and natural gas utilities serving residential customers in the United States as of 2008. Currently, the break-even cost of SWH in the United States varies by more than a factor of five for both electricity and natural gas, despite a much smaller variation in the amount of energy saved by the systems (a factor of approximately one and a half). The break-even price for natural gas is lower than that for electricity due to a lower fuel cost. We also consider the relationship between SWH price and solar fraction and examine the key drivers behind break-even costs. Overall, the key drivers of the break-even cost of SWH are a combination of fuel price, local incentives, and technical factors including the solar resource location, system size, and hot water draw.

  9. Fermilab D-0 Experimental Facility: Energy conservation report and mechanical systems design optimization and cost analysis study

    SciTech Connect

    Krstulovich, S.F.

    1987-10-31

    This report is developed as part of the Fermilab D-0 Experimental Facility Project Title II Design Documentation Update. As such, it concentrates primarily on HVAC mechanical systems design optimization and cost analysis.

  10. [Multi-objective optimization of extraction process for red ginseng based upon extraction efficiency and cost control].

    PubMed

    Zhong, Yi; Zhu, Jie-Qiang; Fan, Xiao-Hui; Kang, Li-Yuan; Li, Zheng

    2014-07-01

    It is the objective of this study to optimize the extraction process of red ginseng to minimize the unit cost of extracting effective ingredients. The relation between the target variables of total quantity of ginsenosides and first extraction time, first extraction solution amount, second extraction time, second extract solution amount were studied with Box-Behnken experimental design method. At the same we also considered the cost of extraction solution and energy usage. The objective function was set as unit cost of target (total quantity of ginsenosides or its purity) for the multi-objective optimization of extraction process. As a result, the optimal process parameters were found as first extraction time (108.7 min), first extraction solution amount folds (12), second extraction time (30 min), second extraction solution amount folds (8) to minimize the unit cost. It indicated that this approach could potentially be used to optimize industrial extraction process for manufacturing Chinese medicine.

  11. Robust multi-objective optimization of state feedback controllers for heat exchanger system with probabilistic uncertainty

    NASA Astrophysics Data System (ADS)

    Lotfi, Babak; Wang, Qiuwang

    2013-07-01

    The performance of thermal control systems has, in recent years, improved in numerous ways due to developments in control theory and information technology. The shell-and-tube heat exchanger (STHX) is a medium where heat transfer process occurred. The accuracy of the heat exchanger depends on the performance of both elements. Therefore, both components need to be controlled in order to achieve a substantial result in the process. For this purpose, the actual dynamics of both shell and tube of the heat exchanger is crucial. In this paper, optimal reliability-based multi-objective Pareto design of robust state feedback controllers for a STHX having parameters with probabilistic uncertainties. Accordingly, the probabilities of failure of those objective functions are also considered in the reliability-based design optimization (RBDO) approach. A new multi-objective uniform-diversity genetic algorithm (MUGA) is presented and used for Pareto optimum design of linear state feedback controllers for STHX problem. In this way, Pareto front of optimum controllers is first obtained for the nominal deterministic STHX using the conflicting objective functions in time domain. Such Pareto front is then obtained for STHX having probabilistic uncertainties in its parameters using the statistical moments of those objective functions through a Hammersley Sequence Sampling (HSS) approach. It is shown that multi-objective reliability-based Pareto optimization of the robust state feedback controllers using MUGA includes those that may be obtained by various crisp threshold values of probability of failures and, thus, remove the difficulty of selecting suitable crisp values. Besides, the multi-objective Pareto optimization of such robust feedback controllers using MUGA unveils some very important and informative trade-offs among those objective functions. Consequently, some optimum robust state feedback controllers can be compromisingly chosen from the Pareto frontiers.

  12. Optimal Placement of Non-Intrusive Waste Heat Recovery Devices in Exhaust Ducts

    DTIC Science & Technology

    2015-06-01

    exchangers for energy recovery in waste and biomass to energy technologies–I. Energy recovery from flue gas,” Appl. Therm. Eng., vol. 64, pp. 213...CODE 13. ABSTRACT (maximum 200 words) The Secretary of the Navy has ordered the U.S. Navy and Marine Corps to reduce energy usage. This study...explores how to optimize placement and size of a non-intrusive waste heat recovery device for energy recovery in exhaust ducts. Additionally, it

  13. On the optimal chamber length and electron heating mechanism in low pressure inductive discharges

    NASA Astrophysics Data System (ADS)

    Kang, Hyun-Ju; Kim, Kyung-Hyun; Lee, Ho-Won; Park, Il-Seo; Chung, Chin-Wook

    2016-09-01

    Plasma resistance with the chamber length was measured at different plasma densities in low pressure inductively coupled plasmas. It was found that the plasma resistance has a maximum at specific chamber length, Lopt, and the Lopt is changed with the plasma density. It is related to the maximum collisionless electron heating, which simultaneously satisfies the conditions of both the bounce resonance and the transit time resonance. Therefore, Lopt is an optimal chamber size for the power transfer to the plasma.

  14. Optimization of activator solution and heat treatment of ground lignite type fly ash geopolymers

    NASA Astrophysics Data System (ADS)

    Molnár, Z.; Szabó, R.; Rácz, Á.; Lakatos, J.; Debreczeni, Á.; Mucsi, G.

    2017-02-01

    Geopolymers are inorganic polymers which can be produced by the reaction between silico aluminate oxides and alkali silicates in alkaline medium. Materialscontaining silica and alumina compounds are suitable for geopolymer production. These can beprimary materials or industrial wastes, i. e. fly ash, metallurgical slag and red mud. In this paper, the results of the systematic experimental series are presented which were carried out in order to optimize the geopolymer preparation process. Fly ash was ground for different residence time (0, 5, 10, 30, 60 min) in order to investigate the optimal specific surface area. NaOH activator solution concentration also varied (6, 8, 10, 12, 14 M). Furthermore, sodium silicate was added to NaOH as a network builder solution. In this last serie different heat curing temperatures (30, 60, 90°C) were also applied. After seven days of ageing the physical properties of the geopolymer(compressive strength and specimen density)were measured. Chemical leaching tests on the rawmaterial and the geopolymers were carried out to determine the elements which can be mobilized by different leaching solutions. It was found that the above mentioned parameters (fly ash fineness, molar concentration and composition of activator solution, heat curing) has great effect on the physical and chemical properties of geopolymer specimens. Optimal conditions were as follows: specific surface area of the fly ash above 2000 cm2/g, 10 M NaOH, 30°C heat curing temperature which resulted in 21 MPa compressive strength geopolymer.

  15. Layer-switching cost and optimality in information spreading on multiplex networks

    PubMed Central

    Min, Byungjoon; Gwak, Sang-Hwan; Lee, Nanoom; Goh, K. -I.

    2016-01-01

    We study a model of information spreading on multiplex networks, in which agents interact through multiple interaction channels (layers), say online vs. offline communication layers, subject to layer-switching cost for transmissions across different interaction layers. The model is characterized by the layer-wise path-dependent transmissibility over a contact, that is dynamically determined dependently on both incoming and outgoing transmission layers. We formulate an analytical framework to deal with such path-dependent transmissibility and demonstrate the nontrivial interplay between the multiplexity and spreading dynamics, including optimality. It is shown that the epidemic threshold and prevalence respond to the layer-switching cost non-monotonically and that the optimal conditions can change in abrupt non-analytic ways, depending also on the densities of network layers and the type of seed infections. Our results elucidate the essential role of multiplexity that its explicit consideration should be crucial for realistic modeling and prediction of spreading phenomena on multiplex social networks in an era of ever-diversifying social interaction layers. PMID:26887527

  16. Energy Smart Guide to Campus Cost Savings: Today's Trends in Project Finance, Clean Fuel Fleets, Combined Heat& Power, Emissions Markets

    SciTech Connect

    Not Available

    2003-07-01

    The Energy Smart Guide to Campus Cost Savings covers today's trends in project finance, combined heat& power, clean fuel fleets and emissions trading. The guide is directed at campus facilities and business managers and contains general guidance, contact information and case studies from colleges and universities across the country.

  17. Optimization of low-cost biosurfactant production from agricultural residues through response surface methodology.

    PubMed

    Ebadipour, N; Lotfabad, T Bagheri; Yaghmaei, S; RoostaAzad, R

    2016-01-01

    Biosurfactants are surface-active compounds capable of reducing surface tension and interfacial tension. Biosurfactants are produced by various microorganisms. They are promising replacements for chemical surfactants because of biodegradability, nontoxicity, and their ability to be produced from renewable sources. However, a major obstacle in producing biosurfactants at the industrial level is the lack of cost-effectiveness. In the present study, by using corn steep liquor (CSL) as a low-cost agricultural waste, not only is the production cost reduced but a higher production yield is also achieved. Moreover, a response surface methodology (RSM) approach through the Box-Behnken method was applied to optimize the biosurfactant production level. The results found that biosurfactant production was improved around 2.3 times at optimum condition when the CSL was at a concentration of 1.88 mL/L and yeast extract was reduced to 25 times less than what was used in a basic soybean oil medium (SOM). The predicted and experimental values of responses were in reasonable agreement with each other (Pred-R(2) = 0.86 and adj-R(2) = 0.94). Optimization led to a drop in raw material price per unit of biosurfactant from $47 to $12/kg. Moreover, the biosurfactant product at a concentration of 84 mg/L could lower the surface tension of twice-distilled water from 72 mN/m to less than 28 mN/m and emulsify an equal volume of kerosene by an emulsification index of (E24) 68% in a two-phase mixture. These capabilities made these biosurfactants applicable in microbial enhanced oil recovery (MEOR), hydrocarbon remediation, and all other petroleum industry surfactant applications.

  18. Multiobjective optimization of water distribution systems accounting for economic cost, hydraulic reliability, and greenhouse gas emissions

    NASA Astrophysics Data System (ADS)

    Wu, Wenyan; Maier, Holger R.; Simpson, Angus R.

    2013-03-01

    In this paper, three objectives are considered for the optimization of water distribution systems (WDSs): the traditional objectives of minimizing economic cost and maximizing hydraulic reliability and the recently proposed objective of minimizing greenhouse gas (GHG) emissions. It is particularly important to include the GHG minimization objective for WDSs involving pumping into storages or water transmission systems (WTSs), as these systems are the main contributors of GHG emissions in the water industry. In order to better understand the nature of tradeoffs among these three objectives, the shape of the solution space and the location of the Pareto-optimal front in the solution space are investigated for WTSs and WDSs that include pumping into storages, and the implications of the interaction between the three objectives are explored from a practical design perspective. Through three case studies, it is found that the solution space is a U-shaped curve rather than a surface, as the tradeoffs among the three objectives are dominated by the hydraulic reliability objective. The Pareto-optimal front of real-world systems is often located at the "elbow" section and lower "arm" of the solution space (i.e., the U-shaped curve), indicating that it is more economic to increase the hydraulic reliability of these systems by increasing pipe capacity (i.e., pipe diameter) compared to increasing pumping power. Solutions having the same GHG emission level but different cost-reliability tradeoffs often exist. Therefore, the final decision needs to be made in conjunction with expert knowledge and the specific budget and reliability requirements of the system.

  19. Designing optimal greenhouse gas observing networks that consider performance and cost

    DOE PAGES

    Lucas, D. D.; Yver Kwok, C.; Cameron-Smith, P.; ...

    2015-06-16

    Emission rates of greenhouse gases (GHGs) entering into the atmosphere can be inferred using mathematical inverse approaches that combine observations from a network of stations with forward atmospheric transport models. Some locations for collecting observations are better than others for constraining GHG emissions through the inversion, but the best locations for the inversion may be inaccessible or limited by economic and other non-scientific factors. We present a method to design an optimal GHG observing network in the presence of multiple objectives that may be in conflict with each other. As a demonstration, we use our method to design a prototypemore » network of six stations to monitor summertime emissions in California of the potent GHG 1,1,1,2-tetrafluoroethane (CH2FCF3, HFC-134a). We use a multiobjective genetic algorithm to evolve network configurations that seek to jointly maximize the scientific accuracy of the inferred HFC-134a emissions and minimize the associated costs of making the measurements. The genetic algorithm effectively determines a set of "optimal" observing networks for HFC-134a that satisfy both objectives (i.e., the Pareto frontier). The Pareto frontier is convex, and clearly shows the tradeoffs between performance and cost, and the diminishing returns in trading one for the other. Without difficulty, our method can be extended to design optimal networks to monitor two or more GHGs with different emissions patterns, or to incorporate other objectives and constraints that are important in the practical design of atmospheric monitoring networks.« less

  20. Stacked Micro Heat Exchange System for Optimized Thermal Coupling of MicroTEGs

    NASA Astrophysics Data System (ADS)

    Wojtas, N.; Grab, M.; Glatz, W.; Hierold, C.

    2013-07-01

    This study presents modeling and experimental results of micro thermoelectric generators (μTEGs) integrated into a multilayer micro heat exchange system. The multilayer configuration benefits from low heat transfer resistances at small fluid flow rates and at the same time from low required pumping powers. The compact stacked power device allows for high net output power per volume, and therefore a reduction in size, weight, and cost compared with conventional large-scale heat exchangers. The influence of the boundary conditions and the system design parameters on the net output power of the micro heat exchange system was investigated by simulation. The theoretical results showed a major impact of the microchannel dimensions and the μTEG thickness on the overall output performance of the system. By adapting the applied fluid flow rate, the system's net power output can be maximized for varying operating temperatures. Experimental measurements of the cross-flow micro heat exchange system were in good agreement with the performed simulations. A net μTEG output power of 62.9 mW/cm2 was measured for a double-layer system at an applied water inlet temperature difference of 60 K with a Bi2Te3 μTEG ( ZT of 0.12), resulting in a net volumetric efficiency factor of 37.2 W/m3/K2.

  1. Surrogates for numerical simulations; optimization of eddy-promoter heat exchangers

    NASA Technical Reports Server (NTRS)

    Patera, Anthony T.; Patera, Anthony

    1993-01-01

    Although the advent of fast and inexpensive parallel computers has rendered numerous previously intractable calculations feasible, many numerical simulations remain too resource-intensive to be directly inserted in engineering optimization efforts. An attractive alternative to direct insertion considers models for computational systems: the expensive simulation is evoked only to construct and validate a simplified, input-output model; this simplified input-output model then serves as a simulation surrogate in subsequent engineering optimization studies. A simple 'Bayesian-validated' statistical framework for the construction, validation, and purposive application of static computer simulation surrogates is presented. As an example, dissipation-transport optimization of laminar-flow eddy-promoter heat exchangers are considered: parallel spectral element Navier-Stokes calculations serve to construct and validate surrogates for the flowrate and Nusselt number; these surrogates then represent the originating Navier-Stokes equations in the ensuing design process.

  2. Thermodynamic Analysis and Optimization of a High Temperature Triple Absorption Heat Transformer

    PubMed Central

    Khamooshi, Mehrdad; Yari, Mortaza; Egelioglu, Fuat; Salati, Hana

    2014-01-01

    First law of thermodynamics has been used to analyze and optimize inclusively the performance of a triple absorption heat transformer operating with LiBr/H2O as the working pair. A thermodynamic model was developed in EES (engineering equation solver) to estimate the performance of the system in terms of the most essential parameters. The assumed parameters are the temperature of the main components, weak and strong solutions, economizers' efficiencies, and bypass ratios. The whole cycle is optimized by EES software from the viewpoint of maximizing the COP via applying the direct search method. The optimization results showed that the COP of 0.2491 is reachable by the proposed cycle. PMID:25136702

  3. Optimization of reaction conditions for improving nutritional properties in heat moisture treated maize starch.

    PubMed

    Ye, Xiaoting; Lu, Fei; Yao, Tianming; Gan, Renyou; Sui, Zhongquan

    2016-12-01

    Impact of heat-moisture treatment (HMT) on nutritional properties of normal maize starch (NMS) under various reaction conditions was investigated. NMS was adjusted to moisture levels of 20%, 25%, 30% and 35% and heated at 80, 100, 120 and 140°C for 4, 8, 12 and 16h. Response surface methodology (RSM) based on Box-Behnken design (BBD) was employed to obtain the optimal combination of moisture level (X1: 20-30%), length of heating (X2: 4-12h), and temperature (X3: 100-140°C). The optimum reaction condition decreased rapidly digestible starch (RDS) from 87.10% to 82.21%, when NMS was subjected to HMT at 23.6% moisture content and heated at 114.8°C for 9.04h. The ANOVA measurement and confirmation experiments were performed to verify the predictive value and the RSM model, indicating that temperature was the main factor to determine the digestion rate of HMT NMS. The results suggested that RDS was not correlated to heating length but positively correlated to temperature and moisture content. Reaction condition had no correlations with slowly digestible starch (SDS) and resistant starch (RS). This study could provide more information for producing low-glycemic index products.

  4. Energy and Cost Optimized Technology Options to Meet Energy Needs of Food Processors

    SciTech Connect

    Makhmalbaf, Atefe; Srivastava, Viraj; Hoffman, Michael G.; Wagner, Anne W.; Thornton, John

    2015-05-01

    Full Paper Submission for: Combined cooling, heating and electric power (CCHP) distributed generation (DG) systems can provide electric power and, heating and cooling capability to commercial and industrial facilities directly onsite, while increasing energy efficiency, security of energy supply, grid independence and enhancing the environmental and economic situation for the site. Food processing industries often have simultaneous requirements for heat, steam, chilling and electricity making them well suited for the use of such systems to supply base-load or as peak reducing generators enabling reduction of overall energy use intensity. This paper documents analysis from a project evaluating opportunities enabled by CCHPDG for emission and cost reductions and energy storage systems installed onsite at food processing facilities. In addition, this distributed generation coupled with energy storage demonstrates a non-wires solution to delay or eliminate the need for upgrades to electric distribution systems. It was found that a dairy processing plant in the Pacific Northwest currently purchasing 15,000 MWh/yr of electricity and 190,000 MMBtu/yr of gas could be provided with a 1.1 MW CCHP system reducing the amount of electric power purchased to 450 MWh/yr while increasing the gas demand to 255,000 MMBtu/yr. The high percentage of hydro-power in this region resulted in CO2 emissions from CCHP to be higher than that attributed to the electric utility/regional energy mix. The value of this work is in documenting a real-world example demonstrating the value of CCHP to facility owners and financial decision makers to encourage them to more seriously consider CCHP systems when building or upgrading facilities.

  5. State estimation bias induced by optimization under uncertainty and error cost asymmetry is likely reflected in perception.

    PubMed

    Shimansky, Y P

    2011-05-01

    It is well known from numerous studies that perception can be significantly affected by intended action in many everyday situations, indicating that perception and related decision-making is not a simple, one-way sequence, but a complex iterative cognitive process. However, the underlying functional mechanisms are yet unclear. Based on an optimality approach, a quantitative computational model of one such mechanism has been developed in this study. It is assumed in the model that significant uncertainty about task-related parameters of the environment results in parameter estimation errors and an optimal control system should minimize the cost of such errors in terms of the optimality criterion. It is demonstrated that, if the cost of a parameter estimation error is significantly asymmetrical with respect to error direction, the tendency to minimize error cost creates a systematic deviation of the optimal parameter estimate from its maximum likelihood value. Consequently, optimization of parameter estimate and optimization of control action cannot be performed separately from each other under parameter uncertainty combined with asymmetry of estimation error cost, thus making the certainty equivalence principle non-applicable under those conditions. A hypothesis that not only the action, but also perception itself is biased by the above deviation of parameter estimate is supported by ample experimental evidence. The results provide important insights into the cognitive mechanisms of interaction between sensory perception and planning an action under realistic conditions. Implications for understanding related functional mechanisms of optimal control in the CNS are discussed.

  6. Optimal three-dimensional reentry trajectories subject to deceleration and heating constraints

    NASA Astrophysics Data System (ADS)

    Chern, J.-S.; Yang, C.-Y.; Vinh, N. X.; Hwang, G. R.

    1982-09-01

    The lateral maneuver of a lifting reentry vehicle, exemplified by the Shuttle entry, is severely restricted by deceleration and heating constraints. This paper investigates the decrease in the lateral reachable domain when different constraints are imposed on the optimal trajectories. A characteristic of hypersonic reentry trajectories is that the deceleration and heating rate pass through several maxima. The first peak is always higher than the following maxima so that it suffices to control the first maximum to the required level. Thermal constraint is encountered at higher altitude so that, in general, thermal control usually limits the deceleration to acceptable level. Using the equilibrium glide assumption, the optimal lift and bank control to maximize the lateral range is obtained in explicit form. Numerical results have been obtained for a typical value of maximum lift-to-drag ratio, and for several values of deceleration and thermal constraints imposed on the entry trajectories. It is found that the peak deceleration and the peak heating rate can be lowered significantly with only a slight penalty on the reachable domain.

  7. Multiple sequence alignment with arbitrary gap costs: computing an optimal solution using polyhedral combinatorics.

    PubMed

    Althaus, Ernst; Caprara, Alberto; Lenhof, Hans-Peter; Reinert, Knut

    2002-01-01

    Multiple sequence alignment is one of the dominant problems in computational molecular biology. Numerous scoring functions and methods have been proposed, most of which result in NP-hard problems. In this paper we propose for the first time a general formulation for multiple alignment with arbitrary gap-costs based on an integer linear program (ILP). In addition we describe a branch-and-cut algorithm to effectively solve the ILP to optimality. We evaluate the performances of our approach in terms of running time and quality of the alignments using the BAliBase database of reference alignments. The results show that our implementation ranks amongst the best programs developed so far.

  8. Computerized systems analysis and optimization of aircraft engine performance, weight, and life cycle costs

    NASA Technical Reports Server (NTRS)

    Fishbach, L. H.

    1979-01-01

    The paper describes the computational techniques employed in determining the optimal propulsion systems for future aircraft applications and to identify system tradeoffs and technology requirements. The computer programs used to perform calculations for all the factors that enter into the selection process of determining the optimum combinations of airplanes and engines are examined. Attention is given to the description of the computer codes including NNEP, WATE, LIFCYC, INSTAL, and POD DRG. A process is illustrated by which turbine engines can be evaluated as to fuel consumption, engine weight, cost and installation effects. Examples are shown as to the benefits of variable geometry and of the tradeoff between fuel burned and engine weights. Future plans for further improvements in the analytical modeling of engine systems are also described.

  9. A risk-reduction approach for optimal software release time determination with the delay incurred cost

    NASA Astrophysics Data System (ADS)

    Peng, Rui; Li, Yan-Fu; Zhang, Jun-Guang; Li, Xiang

    2015-07-01

    Most existing research on software release time determination assumes that parameters of the software reliability model (SRM) are deterministic and the reliability estimate is accurate. In practice, however, there exists a risk that the reliability requirement cannot be guaranteed due to the parameter uncertainties in the SRM, and such risk can be as high as 50% when the mean value is used. It is necessary for the software project managers to reduce the risk to a lower level by delaying the software release, which inevitably increases the software testing costs. In order to incorporate the managers' preferences over these two factors, a decision model based on multi-attribute utility theory (MAUT) is developed for the determination of optimal risk-reduction release time.

  10. Thermodynamic optimization of mixed refrigerant Joule- Thomson systems constrained by heat transfer considerations

    NASA Astrophysics Data System (ADS)

    Hinze, J. F.; Klein, S. A.; Nellis, G. F.

    2015-12-01

    Mixed refrigerant (MR) working fluids can significantly increase the cooling capacity of a Joule-Thomson (JT) cycle. The optimization of MRJT systems has been the subject of substantial research. However, most optimization techniques do not model the recuperator in sufficient detail. For example, the recuperator is usually assumed to have a heat transfer coefficient that does not vary with the mixture. Ongoing work at the University of Wisconsin-Madison has shown that the heat transfer coefficients for two-phase flow are approximately three times greater than for a single phase mixture when the mixture quality is between 15% and 85%. As a result, a system that optimizes a MR without also requiring that the flow be in this quality range may require an extremely large recuperator or not achieve the performance predicted by the model. To ensure optimal performance of the JT cycle, the MR should be selected such that it is entirely two-phase within the recuperator. To determine the optimal MR composition, a parametric study was conducted assuming a thermodynamically ideal cycle. The results of the parametric study are graphically presented on a contour plot in the parameter space consisting of the extremes of the qualities that exist within the recuperator. The contours show constant values of the normalized refrigeration power. This ‘map’ shows the effect of MR composition on the cycle performance and it can be used to select the MR that provides a high cooling load while also constraining the recuperator to be two phase. The predicted best MR composition can be used as a starting point for experimentally determining the best MR.

  11. OPTIMIZATION OF INTERNAL HEAT EXCHANGERS FOR HYDROGEN STORAGE TANKS UTILIZING METAL HYDRIDES

    SciTech Connect

    Garrison, S.; Tamburello, D.; Hardy, B.; Anton, D.; Gorbounov, M.; Cognale, C.; van Hassel, B.; Mosher, D.

    2011-07-14

    Two detailed, unit-cell models, a transverse fin design and a longitudinal fin design, of a combined hydride bed and heat exchanger are developed in COMSOL{reg_sign} Multiphysics incorporating and accounting for heat transfer and reaction kinetic limitations. MatLab{reg_sign} scripts for autonomous model generation are developed and incorporated into (1) a grid-based and (2) a systematic optimization routine based on the Nelder-Mead downhill simplex method to determine the geometrical parameters that lead to the optimal structure for each fin design that maximizes the hydrogen stored within the hydride. The optimal designs for both the transverse and longitudinal fin designs point toward closely-spaced, small cooling fluid tubes. Under the hydrogen feed conditions studied (50 bar), a 25 times improvement or better in the hydrogen storage kinetics will be required to simultaneously meet the Department of Energy technical targets for gravimetric capacity and fill time. These models and methodology can be rapidly applied to other hydrogen storage materials, such as other metal hydrides or to cryoadsorbents, in future work.

  12. Optimization of magnetic refrigerators by tuning the heat transfer medium and operating conditions

    NASA Astrophysics Data System (ADS)

    Ghahremani, Mohammadreza; Aslani, Amir; Bennett, Lawrence; Della Torre, Edward

    A new reciprocating Active Magnetic Regenerator (AMR) experimental device has been designed, built and tested to evaluate the effect of the system's parameters on a reciprocating Active Magnetic Regenerator (AMR) near room temperature. Gadolinium turnings were used as the refrigerant, silicon oil as the heat transfer medium, and a magnetic field of 1.3 T was cycled. This study focuses on the methodology of single stage AMR operation conditions to get a higher temperature span near room temperature. Herein, the main objective is not to report the absolute maximum attainable temperature span seen in an AMR system, but rather to find the system's optimal operating conditions to reach that maximum span. The results of this work show that there is an optimal operating frequency, heat transfer fluid flow rate, flow duration, and displaced volume ratio in an AMR system. It is expected that such optimization and the results provided herein will permit the future design and development of more efficient room-temperature magnetic refrigeration systems.

  13. Characterization and optimization of low cost microfluidic thread based electroanalytical device for micro flow injection analysis.

    PubMed

    Agustini, Deonir; Bergamini, Márcio F; Marcolino-Junior, Luiz Humberto

    2017-01-25

    The micro flow injection analysis (μFIA) is a powerful technique that uses the principles of traditional flow analysis in a microfluidic device and brings a number of improvements related to the consumption of reagents and samples, speed of analysis and portability. However, the complexity and cost of manufacturing processes, difficulty in integrating micropumps and the limited performance of systems employing passive pumps are challenges that must be overcome. Here, we present the characterization and optimization of a low cost device based on cotton threads as microfluidic channel to perform μFIA based on passive pumps with good analytical performance in a simple, easy and inexpensive way. The transport of solutions is made through cotton threads by capillary force facilitated by gravity. After studying and optimizing several features related to the device, were obtained a flow rate of 2.2 ± 0.1 μL s(-1), an analytical frequency of 208 injections per hour, a sample injection volume of 2.0 μL and a waste volume of approximately 40 μL per analysis. For chronoamperometric determination of naproxen, a detection limit of 0.29 μmol L(-1) was reached, with a relative standard deviation (RSD) of 1.69% between injections and a RSD of 3.79% with five different devices. Thus, based on the performance presented by proposed microfluidic device, it is possible to overcome some limitations of the μFIA systems based on passive pumps and allow expansion in the use of this technique.

  14. Neural-network-based online HJB solution for optimal robust guaranteed cost control of continuous-time uncertain nonlinear systems.

    PubMed

    Liu, Derong; Wang, Ding; Wang, Fei-Yue; Li, Hongliang; Yang, Xiong

    2014-12-01

    In this paper, the infinite horizon optimal robust guaranteed cost control of continuous-time uncertain nonlinear systems is investigated using neural-network-based online solution of Hamilton-Jacobi-Bellman (HJB) equation. By establishing an appropriate bounded function and defining a modified cost function, the optimal robust guaranteed cost control problem is transformed into an optimal control problem. It can be observed that the optimal cost function of the nominal system is nothing but the optimal guaranteed cost of the original uncertain system. A critic neural network is constructed to facilitate the solution of the modified HJB equation corresponding to the nominal system. More importantly, an additional stabilizing term is introduced for helping to verify the stability, which reinforces the updating process of the weight vector and reduces the requirement of an initial stabilizing control. The uniform ultimate boundedness of the closed-loop system is analyzed by using the Lyapunov approach as well. Two simulation examples are provided to verify the effectiveness of the present control approach.

  15. Optimization and simulation of low-temperature combustion and heat transfer in an Uhde carbonization furnace

    NASA Astrophysics Data System (ADS)

    Liu, Jun; Zhang, Yongfa; Wang, Ying; Chen, Lei; Liu, Gaihuan

    2016-10-01

    The temperature distribution inside a low-temperature combustion chamber with circuited flame path during the low temperature pyrolysis of lignite was simulated using the computational fluid dynamics software FLUENT. The temperature distribution in the Uhde combustion chamber showed that the temperature is very non-uniform and could therefore not meet the requirements for industrial heat transfer. After optimizing the furnace, by adding a self-made gas-guide structure to the heat transfer section as well as adjusting the gas flow size in the flame path, the temperature distribution became uniform, and the average temperature (550-650 °C) became suitable for industrial low-temperature pyrolysis. The Realizable k-epsilon model, P-1 model, and the Non-premixed model were used to calculate the temperature distribution for the combustion of coke-oven gas and air inside the combustion chamber. Our simulation is consistent with our experimental results within an error range of 40-80 °C. The one-dimensional unsteady state heat conduction differential equation ρ nolimits_{coal} Cnolimits_{coal} partial T/partial t = partial /partial x(λ partial T/partial x) can be used to calculate the heat transfer process. Our results can serve as a first theoretical base and may enable technological advances with regard to lignite pyrolysis.

  16. Intermittent cryogen spray cooling for optimal heat extraction during dermatologic laser treatment.

    PubMed

    Majaron, Boris; Svaasand, Lars O; Aguilar, Guillermo; Nelson, J Stuart

    2002-09-21

    Fast heat extraction is critically important to obtain the maximal benefit of cryogen spray cooling (CSC) during laser therapy of shallow skin lesions, such as port wine stain birthmarks. However, a film of liquid cryogen can build up on the skin surface, impairing heat transfer due to the relatively low thermal conductivity and higher temperature of the film as compared to the impinging spray droplets. In an attempt to optimize the cryogen mass flux, while minimally affecting other spray characteristics, we apply a series of 10 ms spurts with variable duty cycles. Heat extraction dynamics during such intermittent cryogen sprays were measured using a custom-made metal-disc detector. The highest cooling rates were observed at moderate duty cycle levels. This confirms the presence, and offers a practical way to eliminate the adverse effect of liquid cryogen build-up on the sprayed surface. On the other hand, lower duty cycles allow a substantial reduction in the average rate of heat extraction, enabling less aggressive and more efficient CSC for treatment of deeper targets, such as hair follicles.

  17. Using Finite Element Simulation to Optimize the Heat Treatment of Tire Protection Chains

    NASA Astrophysics Data System (ADS)

    Eck, S.; Prevedel, P.; Marsoner, S.; Ecker, W.; Illmeier, M.

    2014-04-01

    The heat treatment of tire protection chains has a major influence on the final product because the high local stresses that arise during quenching may lead to material failure, i.e., quench cracks. The investigations presented in this paper aim at the identification of critical areas in the design of a tire chain link made of 50CrV4 (DIN 1.8159) steel. Parametric studies were conducted by means of finite element (FE) simulation. The FE model enables the calculation of the stress evolution in the chain link during heat treatment. The position of the cracks produced in laboratory quench experiments coincided with the position where the FE simulation model predicted the maximum tensile stress at the end of the quench. Hence, geometry optimization of the chain links is now possible by means of parametric FE studies aiming to minimize these tensile stresses. To identify the influence of the various input parameters on the calculated stress evolution during the quenching, a sensitivity analysis was performed. The influence of the mesh size, the heat transfer at the surface, and the thermo-mechanical properties of the material phases on the stress calculation was evaluated and trends were identified. Temperature measurements during quenching experiments were used to determine the heat transfer parameters. X-ray residual stress measurements on pre-defined positions after an instrumented laboratory quenching were used to validate the simulation results.

  18. Computerized systems analysis and optimization of aircraft engine performance, weight, and life cycle costs

    NASA Technical Reports Server (NTRS)

    Fishbach, L. H.

    1979-01-01

    The computational techniques utilized to determine the optimum propulsion systems for future aircraft applications and to identify system tradeoffs and technology requirements are described. The characteristics and use of the following computer codes are discussed: (1) NNEP - a very general cycle analysis code that can assemble an arbitrary matrix fans, turbines, ducts, shafts, etc., into a complete gas turbine engine and compute on- and off-design thermodynamic performance; (2) WATE - a preliminary design procedure for calculating engine weight using the component characteristics determined by NNEP; (3) POD DRG - a table look-up program to calculate wave and friction drag of nacelles; (4) LIFCYC - a computer code developed to calculate life cycle costs of engines based on the output from WATE; and (5) INSTAL - a computer code developed to calculate installation effects, inlet performance and inlet weight. Examples are given to illustrate how these computer techniques can be applied to analyze and optimize propulsion system fuel consumption, weight, and cost for representative types of aircraft and missions.

  19. Scheduling Multilevel Deadline-Constrained Scientific Workflows on Clouds Based on Cost Optimization

    DOE PAGES

    Malawski, Maciej; Figiela, Kamil; Bubak, Marian; ...

    2015-01-01

    This paper presents a cost optimization model for scheduling scientific workflows on IaaS clouds such as Amazon EC2 or RackSpace. We assume multiple IaaS clouds with heterogeneous virtual machine instances, with limited number of instances per cloud and hourly billing. Input and output data are stored on a cloud object store such as Amazon S3. Applications are scientific workflows modeled as DAGs as in the Pegasus Workflow Management System. We assume that tasks in the workflows are grouped into levels of identical tasks. Our model is specified using mathematical programming languages (AMPL and CMPL) and allows us to minimize themore » cost of workflow execution under deadline constraints. We present results obtained using our model and the benchmark workflows representing real scientific applications in a variety of domains. The data used for evaluation come from the synthetic workflows and from general purpose cloud benchmarks, as well as from the data measured in our own experiments with Montage, an astronomical application, executed on Amazon EC2 cloud. We indicate how this model can be used for scenarios that require resource planning for scientific workflows and their ensembles.« less

  20. Weaving time into system architecture: satellite cost per operational day and optimal design lifetime

    NASA Astrophysics Data System (ADS)

    Saleh, Joseph H.; Hastings, Daniel E.; Newman, Dava J.

    2004-03-01

    An augmented perspective on system architecture is proposed (diachronic) that complements the traditional views on system architecture (synchronic). This paper proposes to view in a system architecture the flow of service (or utility) that the system will provide over its design lifetime. It suggests that the design lifetime is a fundamental component of system architecture although one cannot see it or touch it. Consequently, cost, utility, and value per unit time metrics are introduced. A framework is then developed that identifies optimal design lifetimes for complex systems in general, and space systems in particular, based on this augmented perspective of system architecture and on these metrics. It is found that an optimal design lifetime for a satellite exists, even in the case of constant expected revenues per day over the system's lifetime, and that it changes substantially with the expected Time to Obsolescence of the system and the volatility of the market the system is serving in the case of a commercial venture. The analysis thus proves that it is essential for a system architect to match the design lifetime with the dynamical characteristics of the environment the system is/will be operating in. It is also shown that as the uncertainty in the dynamical characteristics of the environment the system is operating in increases, the value of having the option to upgrade, modify, or extend the lifetime of a system at a later point in time increases depending on how events unfold.

  1. Shellfish mariculture facility which employs passive solar heating and heat pump systems. Performance and cost analysis study. Final report

    SciTech Connect

    Zoto, G.A.; Krabach, M.H.

    1984-06-01

    This report incorporates operations data such as clam growth rates, clam biomass buildup, water volume, and algal food requirements compiled while developing a year-round production schedule for production of hard clam seed. The facility includes a passive solar hatchery and heat pump. Three major areas which affect development of energy-efficient mariculture are addressed: biological operation parameters, energy requirements, and system economics. (LEW)

  2. Optimal control of the power adiabatic stroke of an optomechanical heat engine

    NASA Astrophysics Data System (ADS)

    Bathaee, M.; Bahrampour, A. R.

    2016-08-01

    We consider the power adiabatic stroke of the Otto optomechanical heat engine introduced in Phys. Rev. Lett. 112, 150602 (2014), 10.1103/PhysRevLett.112.150602. We derive the maximum extractable work of both optomechanical normal modes in the minimum time while the system experiences quantum friction effects. We show that the total work done by the system in the power adiabatic stroke is optimized by a bang-bang control. The time duration of the power adiabatic stroke is of the order of the inverse of the effective optomechanical-coupling coefficient. The optimal phase-space trajectory of the Otto cycle for both optomechanical normal modes is also obtained.

  3. IEA solar: Working toward greater cost-effectiveness, report of the International Energy Agency Solar Heating and Cooling Programme

    NASA Astrophysics Data System (ADS)

    Blum, S.

    1986-02-01

    This is the 1985 Annual Report of the International Energy Agency Solar Heating and Cooling (SHC) Program. The format of the report has been changed substantially from that of previous years. In addition, the report has been given a special theme: Working Toward Greater Cost-Effectiveness. Section 2 of this report, the special theme chapter, discusses the contributions of the cooperative activities to achieving more cost-effective solar heating and cooling systems. A report on the progress and accomplishments during 1985 of the current tasks is found in Section 3. Section 4, Appendix, contains a description of each of the tasks as background information for those unfamiliar with all or parts of the program. Finally, the Appendix also contains information on IEA SHC reports, meetings, Executive Committee Members and task technical participants.

  4. Optimal Preventive Maintenance Schedule based on Lifecycle Cost and Time-Dependent Reliability

    DTIC Science & Technology

    2011-11-10

    cost PC , the inspection cost IC and an expected variable cost EVC [2, 32]. These costs are a function of quality and reliability. The lifecycle...expected variable cost EVC is a function of the time- dependent reliability which is used to estimate the expected present value of repairing and/or

  5. Development and optimization of a two-stage gasifier for heat and power production

    NASA Astrophysics Data System (ADS)

    Kosov, V. V.; Zaichenko, V. M.

    2016-11-01

    The major methods of biomass thermal conversion are combustion in excess oxygen, gasification in reduced oxygen, and pyrolysis in the absence of oxygen. The end products of these methods are heat, gas, liquid and solid fuels. From the point of view of energy production, none of these methods can be considered optimal. A two-stage thermal conversion of biomass based on pyrolysis as the first stage and pyrolysis products cracking as the second stage can be considered the optimal method for energy production that allows obtaining synthesis gas consisting of hydrogen and carbon monoxide and not containing liquid or solid particles. On the base of the two stage cracking technology, there was designed an experimental power plant of electric power up to 50 kW. The power plant consists of a thermal conversion module and a gas engine power generator adapted for operation on syngas. Purposes of the work were determination of an optimal operation temperature of the thermal conversion module and an optimal mass ratio of processed biomass and charcoal in cracking chamber of the thermal conversion module. Experiments on the pyrolysis products cracking at various temperatures show that the optimum cracking temperature is equal to 1000 °C. From the results of measuring the volume of gas produced in different mass ratios of charcoal and wood biomass processed, it follows that the maximum volume of the gas in the range of the mass ratio equal to 0.5-0.6.

  6. Virtual Grower: Software to Calculate Heating Costs of Greenhouse Production in the US

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Greenhouses are used in many climates either for season extension or year-round production, and can be expensive to heat. Greenhouse users and growers are often faced with management decisions that rely on an understanding of how temperature settings, heating systems, fuel types, and construction d...

  7. Toward a new spacecraft optimal design lifetime? Impact of marginal cost of durability and reduced launch price

    NASA Astrophysics Data System (ADS)

    Snelgrove, Kailah B.; Saleh, Joseph Homer

    2016-10-01

    The average design lifetime of satellites continues to increase, in part due to the expectation that the satellite cost per operational day decreases monotonically with increased design lifetime. In this work, we challenge this expectation by revisiting the durability choice problem for spacecraft in the face of reduced launch price and under various cost of durability models. We first provide a brief overview of the economic thought on durability and highlight its limitations as they pertain to our problem (e.g., the assumption of zero marginal cost of durability). We then investigate the merging influence of spacecraft cost of durability and launch price, and we identify conditions that give rise cost-optimal design lifetimes that are shorter than the longest lifetime technically achievable. For example, we find that high costs of durability favor short design lifetimes, and that under these conditions the optimal choice is relatively robust to reduction in launch prices. By contrast, lower costs of durability favor longer design lifetimes, and the optimal choice is highly sensitive to reduction in launch price. In both cases, reduction in launch prices translates into reduction of the optimal design lifetime. Our results identify a number of situations for which satellite operators would be better served by spacecraft with shorter design lifetimes. Beyond cost issues and repeat purchases, other implications of long design lifetime include the increased risk of technological slowdown given the lower frequency of purchases and technology refresh, and the increased risk for satellite operators that the spacecraft will be technologically obsolete before the end of its life (with the corollary of loss of value and competitive advantage). We conclude with the recommendation that, should pressure to extend spacecraft design lifetime continue, satellite manufacturers should explore opportunities to lease their spacecraft to operators, or to take a stake in the ownership

  8. User manual for GEOCITY: a computer model for cost analysis of geothermal district-heating-and-cooling systems. Volume I. Main text

    SciTech Connect

    Huber, H.D.; Fassbender, L.L.; Bloomster, C.H.

    1982-09-01

    The purpose of this model is to calculate the costs of residential space heating, space cooling, and sanitary water heating or process heating (cooling) using geothermal energy from a hydrothermal reservoir. The model can calculate geothermal heating and cooling costs for residential developments, a multi-district city, or a point demand such as an industrial factory or commercial building. GEOCITY simulates the complete geothermal heating and cooling system, which consists of two principal parts: the reservoir and fluid transmission system and the distribution system. The reservoir and fluid transmission submodel calculates the life-cycle cost of thermal energy supplied to the distribution system by simulating the technical design and cash flows for the exploration, development, and operation of the reservoir and fluid transmission system. The distribution system submodel calculates the life-cycle cost of heat (chill) delivered by the distribution system to the end-users by simulating the technical design and cash flows for the construction and operation of the distribution system. Geothermal space heating is assumed to be provided by circulating hot water through radiators, convectors, fan-coil units, or other in-house heating systems. Geothermal process heating is provided by directly using the hot water or by circulating it through a process heat exchanger. Geothermal space or process cooling is simulated by circulating hot water through lithium bromide/water absorption chillers located at each building. Retrofit costs for both heating and cooling applications can be input by the user. The life-cycle cost of thermal energy from the reservoir and fluid transmission system to the distribution system and the life-cycle cost of heat (chill) to the end-users are calculated using discounted cash flow analysis.

  9. A dynamic model for the optimization of oscillatory low grade heat engines

    SciTech Connect

    Markides, Christos N.; Smith, Thomas C. B.

    2015-01-22

    The efficiency of a thermodynamic system is a key quantity on which its usefulness and wider application relies. This is especially true for a device that operates with marginal energy sources and close to ambient temperatures. Various definitions of efficiency are available, each of which reveals a certain performance characteristic of a device. Of these, some consider only the thermodynamic cycle undergone by the working fluid, whereas others contain additional information, including relevant internal components of the device that are not part of the thermodynamic cycle. Yet others attempt to factor out the conditions of the surroundings with which the device is interfacing thermally during operation. In this paper we present a simple approach for the modeling of complex oscillatory thermal-fluid systems capable of converting low grade heat into useful work. We apply the approach to the NIFTE, a novel low temperature difference heat utilization technology currently under development. We use the results from the model to calculate various efficiencies and comment on the usefulness of the different definitions in revealing performance characteristics. We show that the approach can be applied to make design optimization decisions, and suggest features for optimal efficiency of the NIFTE.

  10. The Optimized Operation of Gas Turbine Combined Heat and Power Units Oriented for the Grid-Connected Control

    NASA Astrophysics Data System (ADS)

    Xia, Shu; Ge, Xiaolin

    2016-04-01

    In this study, according to various grid-connected demands, the optimization scheduling models of Combined Heat and Power (CHP) units are established with three scheduling modes, which are tracking the total generation scheduling mode, tracking steady output scheduling mode and tracking peaking curve scheduling mode. In order to reduce the solution difficulty, based on the principles of modern algebraic integers, linearizing techniques are developed to handle complex nonlinear constrains of the variable conditions, and the optimized operation problem of CHP units is converted into a mixed-integer linear programming problem. Finally, with specific examples, the 96 points day ahead, heat and power supply plans of the systems are optimized. The results show that, the proposed models and methods can develop appropriate coordination heat and power optimization programs according to different grid-connected control.

  11. A global optimization method synthesizing heat transfer and thermodynamics for the power generation system with Brayton cycle

    NASA Astrophysics Data System (ADS)

    Fu, Rong-Huan; Zhang, Xing

    2016-09-01

    Supercritical carbon dioxide operated in a Brayton cycle offers a numerous of potential advantages for a power generation system, and a lot of thermodynamics analyses have been conducted to increase its efficiency. Because there are a lot of heat-absorbing and heat-lossing subprocesses in a practical thermodynamic cycle and they are implemented by heat exchangers, it will increase the gross efficiency of the whole power generation system to optimize the system combining thermodynamics and heat transfer theory. This paper analyzes the influence of the performance of heat exchangers on the actual efficiency of an ideal Brayton cycle with a simple configuration, and proposes a new method to optimize the power generation system, which aims at the minimum energy consumption. Although the method is operated only for the ideal working fluid in this paper, its merits compared to that only with thermodynamic analysis are fully shown.

  12. Cost-effectiveness of heat and moisture exchangers compared to usual care for pulmonary rehabilitation after total laryngectomy in Poland.

    PubMed

    Retèl, Valesca P; van den Boer, Cindy; Steuten, Lotte M G; Okła, Sławomir; Hilgers, Frans J; van den Brekel, Michiel W

    2015-09-01

    The beneficial physical and psychosocial effects of heat and moisture exchangers (HMEs) for pulmonary rehabilitation of laryngectomy patients are well evidenced. However, cost-effectiveness in terms of costs per additional quality-adjusted life years (QALYs) has not yet been investigated. Therefore, a model-based cost-effectiveness analysis of using HMEs versus usual care (UC) (including stoma covers, suction system and/or external humidifier) for patients after laryngectomy was performed. Primary outcomes were costs, QALYs and incremental cost-effectiveness ratio (ICER). Secondary outcomes were pulmonary infections, and sleeping problems. The analysis was performed from a health care perspective of Poland, using a time horizon of 10 years and cycle length of 1 year. Transition probabilities were derived from various sources, amongst others a Polish randomized clinical trial. Quality of life data was derived from an Italian study on similar patients. Data on frequencies and mortality-related tracheobronchitis and/or pneumonia were derived from a Europe-wide survey amongst head and neck cancer experts. Substantial differences in quality-adjusted survival between the use of HMEs (3.63 QALYs) versus UC (2.95 QALYs) were observed. Total health care costs/patient were 39,553 PLN (9465 Euro) for the HME strategy and 4889 PLN (1168 Euro) for the UC strategy. HME use resulted in fewer pulmonary infections, and less sleeping problems. We could conclude that given the Polish threshold of 99,000 PLN/QALY, using HMEs is cost-effective compared to UC, resulting in 51,326 PLN/QALY (12,264 Euro/QALY) gained for patients after total laryngectomy. For the hospital period alone (2 weeks), HMEs were cost-saving: less costly and more effective.

  13. Asymptotically Optimal Motion Planning for Learned Tasks Using Time-Dependent Cost Maps

    PubMed Central

    Bowen, Chris; Ye, Gu; Alterovitz, Ron

    2015-01-01

    In unstructured environments in people’s homes and workspaces, robots executing a task may need to avoid obstacles while satisfying task motion constraints, e.g., keeping a plate of food level to avoid spills or properly orienting a finger to push a button. We introduce a sampling-based method for computing motion plans that are collision-free and minimize a cost metric that encodes task motion constraints. Our time-dependent cost metric, learned from a set of demonstrations, encodes features of a task’s motion that are consistent across the demonstrations and, hence, are likely required to successfully execute the task. Our sampling-based motion planner uses the learned cost metric to compute plans that simultaneously avoid obstacles and satisfy task constraints. The motion planner is asymptotically optimal and minimizes the Mahalanobis distance between the planned trajectory and the distribution of demonstrations in a feature space parameterized by the locations of task-relevant objects. The motion planner also leverages the distribution of the demonstrations to significantly reduce plan computation time. We demonstrate the method’s effectiveness and speed using a small humanoid robot performing tasks requiring both obstacle avoidance and satisfaction of learned task constraints. Note to Practitioners Motivated by the desire to enable robots to autonomously operate in cluttered home and workplace environments, this paper presents an approach for intuitively training a robot in a manner that enables it to repeat the task in novel scenarios and in the presence of unforeseen obstacles in the environment. Based on user-provided demonstrations of the task, our method learns features of the task that are consistent across the demonstrations and that we expect should be repeated by the robot when performing the task. We next present an efficient algorithm for planning robot motions to perform the task based on the learned features while avoiding obstacles. We

  14. Performance and Costs of Ductless Heat Pumps in Marine-Climate High-Performance Homes -- Habitat for Humanity The Woods

    SciTech Connect

    Lubliner, Michael; Howard, Luke; Hales, David; Kunkle, Rick; Gordon, Andy; Spencer, Melinda

    2016-02-18

    The Woods is a Habitat for Humanity (HFH) community of ENERGY STAR Homes Northwest (ESHNW)-certified homes located in the marine climate of Tacoma/Pierce County, Washington. This research report builds on an earlier preliminary draft 2014 BA report, and includes significant billing analysis and cost effectiveness research from a collaborative, ongoing Ductless Heat Pump (DHP)research effort for Tacoma Public Utilities (TPU) and Bonneville Power Administration (BPA). This report focuses on the results of field testing, modeling, and monitoring of ductless mini-split heat pump hybrid heating systems in seven homes built and first occupied at various times between September 2013 and October 2014. The report also provides WSU documentation of high-performance home observations, lessons learned, and stakeholder recommendations for builders of affordable high-performance housing such as HFH. Tacoma Public Utilities (TPU) and Bonneville Power Administration (BPA). This report focuses on the results of field testing, modeling, and monitoring of ductless mini-split heat pump hybrid heating systems in seven homes built and first occupied at various times between September 2013 and October 2014. The report also provides WSU documentation of high-performance home observations, lessons learned, and stakeholder recommendations for builders of affordable high-performance housing such as HFH.

  15. Estimation of in-situ bioremediation system cost using a hybrid Extreme Learning Machine (ELM)-particle swarm optimization approach

    NASA Astrophysics Data System (ADS)

    Yadav, Basant; Ch, Sudheer; Mathur, Shashi; Adamowski, Jan

    2016-12-01

    In-situ bioremediation is the most common groundwater remediation procedure used for treating organically contaminated sites. A simulation-optimization approach, which incorporates a simulation model for groundwaterflow and transport processes within an optimization program, could help engineers in designing a remediation system that best satisfies management objectives as well as regulatory constraints. In-situ bioremediation is a highly complex, non-linear process and the modelling of such a complex system requires significant computational exertion. Soft computing techniques have a flexible mathematical structure which can generalize complex nonlinear processes. In in-situ bioremediation management, a physically-based model is used for the simulation and the simulated data is utilized by the optimization model to optimize the remediation cost. The recalling of simulator to satisfy the constraints is an extremely tedious and time consuming process and thus there is need for a simulator which can reduce the computational burden. This study presents a simulation-optimization approach to achieve an accurate and cost effective in-situ bioremediation system design for groundwater contaminated with BTEX (Benzene, Toluene, Ethylbenzene, and Xylenes) compounds. In this study, the Extreme Learning Machine (ELM) is used as a proxy simulator to replace BIOPLUME III for the simulation. The selection of ELM is done by a comparative analysis with Artificial Neural Network (ANN) and Support Vector Machine (SVM) as they were successfully used in previous studies of in-situ bioremediation system design. Further, a single-objective optimization problem is solved by a coupled Extreme Learning Machine (ELM)-Particle Swarm Optimization (PSO) technique to achieve the minimum cost for the in-situ bioremediation system design. The results indicate that ELM is a faster and more accurate proxy simulator than ANN and SVM. The total cost obtained by the ELM-PSO approach is held to a minimum

  16. Optimizing ELF/VLF generation via HF heating utilizing beam motion

    NASA Astrophysics Data System (ADS)

    Cohen, M. B.; Inan, U. S.; Lehtinen, N. G.; Golkowski, M. A.

    2008-12-01

    ELF/VLF (300 Hz - 30 kHz) waves are difficult to generate with conventional antennae due to their extraordinary long wavelengths, and the good conductance of the Earth at these frequencies. Recently, ELF and VLF waves have been generated using HF (3-10 MHz) heating of the lower ionosphere, in the presence of natural currents such as the auroral electrojet, which modulates the ionospheric conductivity and therefore turns the lower ionosphere into a large radiating element. The recently upgraded HAARP facility, near Gakona Alaska, utilizes 3.6 MW of HF power, along with an unprecedented ability to steer the HF heating beam over a large area extremely rapidly. Since the completion of the upgrade in 2007, the first successful implementation of techniques such as geometric modulation [Cohen et al. 2008, Borisov et al. 1998], and beam painting [Papadopoulos et al. 1989] have occurred. These results have shown as much as 7-11 dB improvement in the signal strengths, as well as the first ability to direct ELF/VLF signals via an unprecedented ELF/VLF phased array. Here, we use a combination of experimental and theoretical investigations to discuss the optimization of ELF/VLF generation via HF heating, including the effect of HF and ELF frequency on the amplitude and the directional pattern for various generation techniques. The experimental observations occur over an array of receivers across Alaska. The theoretical formulation utilizes a 3D model of the HF heating and subsequent electron cooling processes, leading to spatial structure of modulated ionospheric conductivities, the results of which are input into a model of ELF/VLF propagation in the Earth-ionosphere waveguide.

  17. A PC program to optimize system configuration for desired reliability at minimum cost

    NASA Technical Reports Server (NTRS)

    Hills, Steven W.; Siahpush, Ali S.

    1994-01-01

    High reliability is desired in all engineered systems. One way to improve system reliability is to use redundant components. When redundant components are used, the problem becomes one of allocating them to achieve the best reliability without exceeding other design constraints such as cost, weight, or volume. Systems with few components can be optimized by simply examining every possible combination but the number of combinations for most systems is prohibitive. A computerized iteration of the process is possible but anything short of a super computer requires too much time to be practical. Many researchers have derived mathematical formulations for calculating the optimum configuration directly. However, most of the derivations are based on continuous functions whereas the real system is composed of discrete entities. Therefore, these techniques are approximations of the true optimum solution. This paper describes a computer program that will determine the optimum configuration of a system of multiple redundancy of both standard and optional components. The algorithm is a pair-wise comparative progression technique which can derive the true optimum by calculating only a small fraction of the total number of combinations. A designer can quickly analyze a system with this program on a personal computer.

  18. Ground Source Heat Pumps vs. Conventional HVAC: A Comparison of Economic and Environmental Costs

    DTIC Science & Technology

    2009-03-26

    modular, decentralized systems in new construction. There are several reasons for this, but the two most common are maintenance and redundancy. As...heating mode. A heat pump is simply a machine that takes advantage of the well understood principles of the mechanical two -phase closed vapor...low solids content of 35-40% (Baroid Industrial Drilling Products, 2008). This relatively new product requires more scientific testing to ensure

  19. Using ant colony optimization on the quadratic assignment problem to achieve low energy cost in geo-distributed data centers

    NASA Astrophysics Data System (ADS)

    Osei, Richard

    There are many problems associated with operating a data center. Some of these problems include data security, system performance, increasing infrastructure complexity, increasing storage utilization, keeping up with data growth, and increasing energy costs. Energy cost differs by location, and at most locations fluctuates over time. The rising cost of energy makes it harder for data centers to function properly and provide a good quality of service. With reduced energy cost, data centers will have longer lasting servers/equipment, higher availability of resources, better quality of service, a greener environment, and reduced service and software costs for consumers. Some of the ways that data centers have tried to using to reduce energy costs include dynamically switching on and off servers based on the number of users and some predefined conditions, the use of environmental monitoring sensors, and the use of dynamic voltage and frequency scaling (DVFS), which enables processors to run at different combinations of frequencies with voltages to reduce energy cost. This thesis presents another method by which energy cost at data centers could be reduced. This method involves the use of Ant Colony Optimization (ACO) on a Quadratic Assignment Problem (QAP) in assigning user request to servers in geo-distributed data centers. In this paper, an effort to reduce data center energy cost involves the use of front portals, which handle users' requests, were used as ants to find cost effective ways to assign users requests to a server in heterogeneous geo-distributed data centers. The simulation results indicate that the ACO for Optimal Server Activation and Task Placement algorithm reduces energy cost on a small and large number of users' requests in a geo-distributed data center and its performance increases as the input data grows. In a simulation with 3 geo-distributed data centers, and user's resource request ranging from 25,000 to 25,000,000, the ACO algorithm was able

  20. Heat, electricity, or transportation? The optimal use of residual and waste biomass in Europe from an environmental perspective.

    PubMed

    Steubing, Bernhard; Zah, Rainer; Ludwig, Christian

    2012-01-03

    The optimal use of forest energy wood, industrial wood residues, waste wood, agricultural residues, animal manure, biowaste, and sewage sludge in 2010 and 2030 was assessed for Europe. An energy system model was developed comprising 13 principal fossil technologies for the production of heat, electricity, and transport and 173 bioenergy conversion routes. The net environmental benefits of substituting fossil energy with bioenergy were calculated for all approximately 1500 combinations based on life cycle assessment (LCA) results. An optimization model determines the best use of biomass for different environmental indicators within the quantified EU-27 context of biomass availability and fossil energy utilization. Key factors determining the optimal use of biomass are the conversion efficiencies of bioenergy technologies and the kind and quantity of fossil energy technologies that can be substituted. Provided that heat can be used efficiently, optimizations for different environmental indicators almost always indicate that woody biomass is best used for combined heat and power generation, if coal, oil, or fuel oil based technologies can be substituted. The benefits of its conversion to SNG or ethanol are significantly lower. For non-woody biomass electricity generation, transportation, and heating yield almost comparable benefits as long as high conversion efficiencies and optimal substitutions are assured. The shares of fossil heat, electricity, and transportation that could be replaced with bioenergy are also provided.

  1. Determination of the optimal time and cost of manufacturing flow of an assembly using the Taguchi method

    NASA Astrophysics Data System (ADS)

    Petrila, S.; Brabie, G.; Chirita, B.

    2016-08-01

    The optimization of the parts and assembly manufacturing operation was carried out in order to minimize both the time and cost of production as appropriate. The optimization was made by using the Taguchi method. The Taguchi method is based on the plans of experiences that vary the input and outputs factors. The application of the Taguchi method in order to optimize the flow of the analyzed assembly production is made in the following: to find the optimal combination between the manufacturing operations; to choose the variant involving the use of equipment performance; to delivery operations based on automation. The final aim of the Taguchi method application is that the entire assembly to be achieved at minimum cost and in a short time. Philosophy Taguchi method of optimizing product quality is synthesized from three basic concepts: quality must be designed into the product and not he product inspected after it has been manufactured; the higher quality is obtained when the deviation from the proposed target is low or when uncontrollable factors action has no influence on it, which translates robustness; costs entailed quality are expressed as a function of deviation from the nominal value [1]. When determining the number of experiments involving the study of a phenomenon by this method, follow more restrictive conditions [2].

  2. [Receiver operating characteristic analysis and the cost--benefit analysis in determination of the optimal cut-off point].

    PubMed

    Vránová, J; Horák, J; Krátká, K; Hendrichová, M; Kovaírková, K

    2009-01-01

    An overview of the use of Receiver Operating Characteristic (ROC) analysis within medicine is provided. A survey of the theory behind the analysis is offered together with a presentation on how to create a ROC curve and how to use Cost--Benefit analysis to determine the optimal cut-off point or threshold. The use of ROC analysis is exemplified in the "Cost--Benefit analysis" section of the paper. In these examples, it can be seen that the determination of the optimal cut-off point is mainly influenced by the prevalence and the severity of the disease, by the risks and adverse events of treatment or the diagnostic testing, by the overall costs of treating true and false positives (TP and FP), and by the risk of deficient or non-treatment of false negative (FN) cases.

  3. Cost-benefit study of consumer product take-back programs using IBM's WIT reverse logistics optimization tool

    NASA Astrophysics Data System (ADS)

    Veerakamolmal, Pitipong; Lee, Yung-Joon; Fasano, J. P.; Hale, Rhea; Jacques, Mary

    2002-02-01

    In recent years, there has been increased focus by regulators, manufacturers, and consumers on the issue of product end of life management for electronics. This paper presents an overview of a conceptual study designed to examine the costs and benefits of several different Product Take Back (PTB) scenarios for used electronics equipment. The study utilized a reverse logistics supply chain model to examine the effects of several different factors in PTB programs. The model was done using the IBM supply chain optimization tool known as WIT (Watson Implosion Technology). Using the WIT tool, we were able to determine a theoretical optimal cost scenario for PTB programs. The study was designed to assist IBM internally in determining theoretical optimal Product Take Back program models and determining potential incentives for increasing participation rates.

  4. Investigation of low-cost ablative heat shield fabrication for space shuttles

    NASA Technical Reports Server (NTRS)

    Chandler, H. H.

    1972-01-01

    Improvements in the processes and design to reduce the manufacturing costs for low density ablative panels for the space shuttle are discussed. The areas that were studied included methods of loading honeycomb core, alternative reinforcement concepts, and the use of reusable subpanels. A review of previous studies on the fabrication of low-cost ablative panels and on permissible defects that do not affect thermal performance was conducted. Considerable differences in the quoted prices for ablative panels, even though the various contractors had reported similar fabrication times were discovered. How these cost differences arise from different estimating criteria and which estimating assumptions and other costs must be included in order to arrive at a realistic price are discussed.

  5. Comparison and Validation of Operational Cost in Smart Houses with the Introduction of a Heat Pump or a Gas Engine

    NASA Astrophysics Data System (ADS)

    Shimoji, Tsubasa; Tahara, Hayato; Matayoshi, Hidehito; Yona, Atsushi; Senjyu, Tomonobu

    2015-02-01

    Due to the concerns of global warming and the depletion of energy resources, renewable energies such as wind generation (WG) and photovoltaic generation (PV) are gaining attention in distribution systems. Efficient electric equipment such as heat pumps (HP) not only contribute low levels of carbon to society, but are also beneficial for consumers. In addition, gas instruments such as the gas engine (GE) and fuel cells (FC) are expected to reduce electricity cost by exhaust heat. Thus, it is important to clarify which systems (HP or GE) are more beneficial for consumers throughout the year. This paper compares the operational cost for the smart house between using the HP and the GE. Current electricity and gas prices are used to calculate the cost of the smart house. The system considered in this research comprises a PV, battery, solar collector (SC), uncontrolled load and either an HP or a GE. In order to verify the effectiveness of the proposed system, MATLAB is used for simulations.

  6. A genetic algorithm-based optimization model for pool boiling heat transfer on horizontal rod heaters at isolated bubble regime

    NASA Astrophysics Data System (ADS)

    Alavi Fazel, S. Ali

    2017-03-01

    A new optimized model which can predict the heat transfer in the nucleate boiling at isolated bubble regime is proposed for pool boiling on a horizontal rod heater. This model is developed based on the results of direct observations of the physical boiling phenomena. Boiling heat flux, wall temperature, bubble departing diameter, bubble generation frequency and bubble nucleation site density have been experimentally measured. Water and ethanol have been used as two different boiling fluids. Heating surface was made by several metals and various degrees of roughness. The mentioned model considers various mechanisms such as latent heat transfer due to micro-layer evaporation, transient conduction due to thermal boundary layer reformation, natural convection, heat transfer due to the sliding bubbles and bubble super-heating. The fractional contributions of individual mentioned heat transfer mechanisms have been calculated by genetic algorithm. The results show that at wall temperature difference more that about 3 K, bubble sliding transient conduction, non-sliding transient conduction, micro-layer evaporation, natural convection, radial forced convection and bubble super-heating have higher to lower fractional contributions respectively. The performance of the new optimized model has been verified by comparison of the existing experimental data.

  7. Choice and optimization of ratio of components to develop fast-mounted thermostable heat-insulating constructions

    NASA Astrophysics Data System (ADS)

    Loginova, N. A.; Grigor'ev, S. V.; Lapin, E. E.; Pogorelov, S. I.; Ryzhenkov, A. V.

    2016-05-01

    Fast-mounted heat-insulating constructions based on foamed synthetic rubbers, polyethylene, and polyurethane are characterized by a thermostability up to 150°C and emit toxic substances when burnt. However, there is a need for heat insulation of surfaces with higher coolant temperatures, such as pipelines, equipment of nuclear and thermal power plants, and heating systems with remote heat sources. One of the most promising types of heat insulation materials for creation of fast-mounted heat insulation constructions is the syntactic foams or thin-film multilayer heat-insulating coatings (TFMHIC), which are created using hollow microspheres and various types of binders. The formation of TFMHIC on the heat-insulating surface is carried out mostly by means of spraying methods that have well proven themselves at coating on flat and cylindrical surfaces of large area, but they turned out ineffective for cylindrical surfaces with a diameter of 300 mm and less, since they are characterized by a large degree of carryover of composite material. This article analyzed the binders and microspheres promising to create the fast-mounted heat-insulating constructions based on TFMHIC with high thermostability. Based on the analysis, a conclusion is drawn that organicsilicon binding and glass microspheres are promising for use in the heat-insulating constructions with thermostability up to 300°C. The results of experimental research are given that point to the possibility of predicting the optimal composition of heat-insulating material characterized by a high degree of filling with microspheres with maintaining the mechanical strength, by means of performing the analysis of rheological characteristics of nonpolymerized liquid compositions of heat-insulation material. The index of tensile strength in bending was the criterion for evaluating the mechanical strength of heat-insulating material. The critical volume concentrations of filling the heat-insulating material with glass

  8. Low-cost Electromagnetic Heating Technology for Polymer Extrusion-based Additive Manufacturing

    SciTech Connect

    Carter, William G.; Rios, Orlando; Akers, Ronald R.; Morrison, William A.

    2016-01-07

    To improve the flow of materials used in in polymer additive manufacturing, ORNL and Ajax Tocco created an induction system for heating fused deposition modeling (FDM) nozzles used in polymer additive manufacturing. The system is capable of reaching a temperature of 230 C, a typical nozzle temperature for extruding ABS polymers, in 17 seconds. A prototype system was built at ORNL and sent to Ajax Tocco who analyzed the system and created a finalized power supply. The induction system was mounted to a PrintSpace Altair desktop printer and used to create several test parts similar in quality to those created using a resistive heated nozzle.

  9. Towards thermal design optimization of tubular digesters in cold climates: a heat transfer model.

    PubMed

    Perrigault, Thibault; Weatherford, Vergil; Martí-Herrero, Jaime; Poggio, Davide

    2012-11-01

    A cold climate, low cost, tubular digester is monitored and temperatures from different parts of the slurry, greenhouse, and adobe walls are presented, discussing the thermal performance of the digester. The slurry exhibits a vertical gradient of 6°C, with a mean value of 24.5°C, while the ambient temperature varies from 10°C to 30°C, showing the efficiency of the system as a solar heat collector with thermal inertia. A simple time-dependent thermal model is developed using inputs of solar radiation, wind velocity, ambient temperature, and digester geometry. The model outputs include temperatures of the slurry, the biogas, its holding membrane and the greenhouse air, wall and cover. Radiative, convective and conductive heat transfer phenomena are considered between all system elements. The model has 0.47°C (2%) standard error for the average slurry temperature. This model can be used to predict the influence of geometry and materials on the performance of the digester.

  10. Optimal homotopy perturbation method for nonlinear differential equations governing MHD Jeffery-Hamel flow with heat transfer problem

    NASA Astrophysics Data System (ADS)

    Marinca, Vasile; Ene, Remus-Daniel

    2017-01-01

    In this paper, the Optimal Homotopy Perturbation Method (OHPM) is employed to determine an analytic approximate solution for the nonlinear MHD Jeffery-Hamel flow and heat transfer problem. The Navier-Stokes equations, taking into account Maxwell's electromagnetism and heat transfer, lead to two nonlinear ordinary differential equations. The results obtained by means of OHPM show very good agreement with numerical results and with Homotopy Perturbation Method (HPM) results.

  11. Optimizing ion-cyclotron resonance frequency heating for ITER: dedicated JET experiments

    NASA Astrophysics Data System (ADS)

    Lerche, E.; Van Eester, D.; Ongena, J.; Mayoral, M.-L.; Laxaback, M.; Rimini, F.; Argouarch, A.; Beaumont, P.; Blackman, T.; Bobkov, V.; Brennan, D.; Brett, A.; Calabro, G.; Cecconello, M.; Coffey, I.; Colas, L.; Coyne, A.; Crombe, K.; Czarnecka, A.; Dumont, R.; Durodie, F.; Felton, R.; Frigione, D.; Gatu Johnson, M.; Giroud, C.; Gorini, G.; Graham, M.; Hellesen, C.; Hellsten, T.; Huygen, S.; Jacquet, P.; Johnson, T.; Kiptily, V.; Knipe, S.; Krasilnikov, A.; Lamalle, P.; Lennholm, M.; Loarte, A.; Maggiora, R.; Maslov, M.; Messiaen, A.; Milanesio, D.; Monakhov, I.; Nightingale, M.; Noble, C.; Nocente, M.; Pangioni, L.; Proverbio, I.; Sozzi, C.; Stamp, M.; Studholme, W.; Tardocchi, M.; Versloot, T. W.; Vdovin, V.; Vrancken, M.; Whitehurst, A.; Wooldridge, E.; Zoita, V.; EFDA Contributors, JET

    2011-12-01

    In the past years, one of the focal points of the JET experimental programme was on ion-cyclotron resonance heating (ICRH) studies in view of the design and exploitation of the ICRH system being developed for ITER. In this brief review, some of the main achievements obtained in JET in this field during the last 5 years will be summarized. The results reported here include important aspects of a more engineering nature, such as (i) the appropriate design of the RF feeding circuits for optimal load resilient operation and (ii) the test of a compact high-power density antenna array, as well as RF physics oriented studies aiming at refining the numerical models used for predicting the performance of the ICRH system in ITER. The latter include (i) experiments designed for improving the modelling of the antenna coupling resistance under various plasma conditions and (ii) the assessment of the heating performance of ICRH scenarios to be used in the non-active operation phase of ITER.

  12. On optimizing high-pressure freezing: from heat transfer theory to a new microbiopsy device.

    PubMed

    Shimoni, E; Müller, M

    1998-12-01

    High-pressure freezing (HPF) is currently the only method which enables adequate cryoimmobilization of biological samples thick enough to describe the bulk of the sample. In the current state of HPF instrumentation and preparation methods, the technique has not yet reached its full potential. While suspensions can be prepared easily for HPF, tissue preparation is restricted by the need to compromise between different requirements and difficulties. (i) In order to achieve optimal freezing quality, very thin samples are required. (ii) There is mechanical difficulty in cutting such thin samples without distorting the organization of the tissue. (iii) The cutting and the succeeding preparation steps of small samples require long handling times (minutes), which may result in physiological and hence structural alterations. Computerized heat transfer simulations are presented which confirm that the efficiency of heat extraction from cylindrical samples contained within thin-walled metal tubes is higher than from standard flat discoid samples sandwiched between relatively thick aluminium platelets. Based on this fact, we developed a prototype of a new microbiopsy device which enables the quick excision of such cylinders of soft tissues. The device utilizes sharp gold needles of an inner diameter of 200 microm and wall thickness of 50 microm. The frozen sample contained in the soft gold needle permits all the manipulations needed for conventional cryo-preparation techniques for electron microscopy (e.g. cryo-sectioning, freeze-fracturing, freeze-substitution).

  13. Mechanism analysis of Magnetohydrodynamic heat shield system and optimization of externally applied magnetic field

    NASA Astrophysics Data System (ADS)

    Li, Kai; Liu, Jun; Liu, Weiqiang

    2017-04-01

    As a novel thermal protection technique for hypersonic vehicles, Magnetohydrodynamic (MHD) heat shield system has been proved to be of great intrinsic value in the hypersonic field. In order to analyze the thermal protection mechanisms of such a system, a physical model is constructed for analyzing the effect of the Lorentz force components in the counter and normal directions. With a series of numerical simulations, the dominating Lorentz force components are analyzed for the MHD heat flux mitigation in different regions of a typical reentry vehicle. Then, a novel magnetic field with variable included angle between magnetic induction line and streamline is designed, which significantly improves the performance of MHD thermal protection in the stagnation and shoulder areas. After that, the relationships between MHD shock control and MHD thermal protection are investigated, based on which the magnetic field above is secondarily optimized obtaining better performances of both shock control and thermal protection. Results show that the MHD thermal protection is mainly determined by the Lorentz force's effect on the boundary layer. From the stagnation to the shoulder region, the flow deceleration effect of the counter-flow component is weakened while the flow deflection effect of the normal component is enhanced. Moreover, there is no obviously positive correlation between the MHD shock control and thermal protection. But once a good Lorentz force's effect on the boundary layer is guaranteed, the thermal protection performance can be further improved with an enlarged shock stand-off distance by strengthening the counter-flow Lorentz force right after shock.

  14. Fuel Cell Power Model Elucidates Life-Cycle Costs for Fuel Cell-Based Combined Heat, Hydrogen, and Power (CHHP) Production Systems (Fact Sheet)

    SciTech Connect

    Not Available

    2010-11-01

    This fact sheet describes NREL's accomplishments in accurately modeling costs for fuel cell-based combined heat, hydrogen, and power systems. Work was performed by NREL's Hydrogen Technologies and Systems Center.

  15. Screening and optimization of low-cost medium for Pseudomonas putida Rs-198 culture using RSM.

    PubMed

    Peng, Yanjie; He, Yanhui; Wu, Zhansheng; Lu, Jianjiang; Li, Chun

    2014-01-01

    The plant growth-promoting rhizobacterial strain Pseudomonas putida Rs-198 was isolated from salinized soils from Xinjiang Province. We optimized the composition of the low-cost medium of P. putida Rs-198 based on its bacterial concentration, as well as its phosphate-dissolving and indole acetic acid (IAA)-producing capabilities using the response surface methodology (RSM), and a mathematical model was developed to show the effect of each medium component and its interactions on phosphate dissolution and IAA production. The model predicted a maximum phosphate concentration in medium containing 63.23 mg/L inorganic phosphate with 49.22 g/L corn flour, 14.63 g/L soybean meal, 2.03 g/L K₂HPO₄, 0.19 g/L MnSO₄ and 5.00 g/L NaCl. The maximum IAA concentration (18.73 mg/L) was predicted in medium containing 52.41 g/L corn flour, 15.82 g/L soybean meal, 2.40 g/L K₂HPO₄, 0.17 g/L MnSO₄ and 5.00 g/L NaCl. These predicted values were also verified through experiments, with a cell density of 10(13) cfu/mL, phosphate dissolution of 64.33 mg/L, and IAA concentration of 18.08 mg/L. The excellent correlation between predicted and measured values of each model justifies the validity of both the response models. The study aims to provide a basis for industrialized fermentation using P. putida Rs-198.

  16. Screening and optimization of low-cost medium for Pseudomonas putida Rs-198 culture using RSM

    PubMed Central

    Peng, Yanjie; He, Yanhui; Wu, Zhansheng; Lu, Jianjiang; Li, Chun

    2014-01-01

    The plant growth-promoting rhizobacterial strain Pseudomonas putida Rs-198 was isolated from salinized soils from Xinjiang Province. We optimized the composition of the low-cost medium of P. putida Rs-198 based on its bacterial concentration, as well as its phosphate-dissolving and indole acetic acid (IAA)-producing capabilities using the response surface methodology (RSM), and a mathematical model was developed to show the effect of each medium component and its interactions on phosphate dissolution and IAA production. The model predicted a maximum phosphate concentration in medium containing 63.23 mg/L inorganic phosphate with 49.22 g/L corn flour, 14.63 g/L soybean meal, 2.03 g/L K2HPO4, 0.19 g/L MnSO4 and 5.00 g/L NaCl. The maximum IAA concentration (18.73 mg/L) was predicted in medium containing 52.41 g/L corn flour, 15.82 g/L soybean meal, 2.40 g/L K2HPO4, 0.17 g/L MnSO4 and 5.00 g/L NaCl. These predicted values were also verified through experiments, with a cell density of 1013 cfu/mL, phosphate dissolution of 64.33 mg/L, and IAA concentration of 18.08 mg/L. The excellent correlation between predicted and measured values of each model justifies the validity of both the response models. The study aims to provide a basis for industrialized fermentation using P. putida Rs-198. PMID:25763026

  17. Cost of transport and optimal swimming speed in farmed and wild European silver eels (Anguilla anguilla).

    PubMed

    Palstra, Arjan; van Ginneken, Vincent; van den Thillart, Guido

    2008-09-01

    A swimming speed of 0.4 meters per second (m s(-1)) is the minimal speed for European female silver eels to reach the spawning sites in the Sargasso Sea in time. As silver eels cease feeding when they start their oceanic migration, the cost of transport (COT) should be minimised and the swimming speed optimised to attain the highest energetic efficiency. In this study, we have investigated the optimal swimming speed (U(opt)) of silver eels since U(opt) may be higher than the minimal swimming speed and is more likely to resemble the actual cruise speed. A variety of swimming tests were performed to compare endurance swimming between farmed eels and wild eels, both in freshwater and in seawater. The swimming tests were run with 101 silver female eels (60-96 cm, 400-1500 g) in 22 Blazka-type swim tunnels in a climatised room at 18 degrees C with running freshwater or seawater. Tests were run at 0.5-1.0 m s(-1) with increments of 0.1 m s(-1), and either 2 h or 12 h intervals. Remarkably, both tests revealed no changes in oxygen consumption (M O2) and COT over time. U(opt) values ranged between 0.61 and 0.68 m s(-1) (0.74-1.02 BL s(-1)) for the different groups and were thus 53-70% higher than the minimal speed. At U(opt), the COT was 37-50 mg O2 kg(-1) km(-1). These relatively very low values confirm our earlier observations. COT values in seawater were about 20% higher than in freshwater. Assuming that migrating female silver eels cruise at their U(opt), they will be able to cover the distance to the Sargasso Sea in 3-4 months, leaving ample time for final maturation and finding mates.

  18. Optimal thermionic energy conversion with established electrodes for high-temperature topping and process heating

    SciTech Connect

    Morris, J.F.

    1980-07-01

    Advantages of thermionic energy conversion (TEC) have been counted and are recounted with emphasis on high-temperature service in coal-combustion products. Efficient, economical, nonpolluting utilization of coal here and now is a critically important national goal. And TEC can augment this capability not only by the often proposed topping of steam power plants but also by higher-temperature topping and process heating. For these applications, applied-research-and-technology (ART) work reveals that optimal TEC with approx. 1000-to approx. 1100 K collectors is possible using well-established tungsten electrodes. Such TEC with 1800 K emitters could approach 26.6% efficiency at 27.4 W/cm/sup 2/ with approx. 1000 K collectors and 21.7% at 22.6 W/cm/sup 2/ with approx. 1100 K collectors. These performances require 1.5- and 1.7-eV collector work functions (not the 1-eV ultimate) with nearly negligible interelectrode losses. Such collectors correspond to tungsten electrode systems in approx. 0.9-to approx. 6-torr cesium pressures with 1600-to-1900 K emitters. Because higher heat-rejection temperatures for TEC allow greater collector work functions, interelectrode-loss reduction becomes an increasingly important target for applications aimed at elevated temperatures. Studies of intragap modifications and new electrodes that will allow better electron emission and collection with lower cesium pressures are among the TEC-ART approaches to reduced interelectrode losses. These solutions will provide very effective TEC to serve directly in coal-combustion products for high-temperature topping and process heating. In turn this will help to use coal-and to use it well.

  19. Cost and Performance Review of Electrical Resistance Heating (ERH) for Source Treatment

    DTIC Science & Technology

    2007-03-01

    phase liquid ( DNAPL ) or high concentrations of volatile contaminants. ERH is a remediation technology that involves passing electrical current...Electrical resistant heating (ERH), Naval Facilities Engineering Service Center (NFESC), remediation, nonaqueous-phase liquid ( DNAPL ) 16. SECURITY...Camp Lejeune. Performance data from these sites indicate that ERH treats dense nonaqueous-phase liquid ( DNAPL ) source zones through a variety of

  20. Feeling the Heat: The Impact of Rising Energy Costs on Colleges & Universities in the Midwest

    ERIC Educational Resources Information Center

    Rasmussen, Chris; Johnson, Gina

    2006-01-01

    This report is the result of a survey conducted in late 2005 of higher education institution chief financial officers throughout the U.S. Midwest region concerning their plans to manage what was expected to be a substantial increase in the price of energy in advance of the 2005-06 heating season. Although the winter turned out to be one of the…

  1. Are specialized endotracheal tubes and heat-and-moisture exchangers cost-effective in preventing ventilator associated pneumonia?

    PubMed

    Gentile, Michael A; Siobal, Mark S

    2010-02-01

    Ventilator-associated pneumonia (VAP) is a common and serious complication of mechanical ventilation via an artificial airway. As with all nosocomial infections, VAP increases costs, morbidity, and mortality in the intensive care unit (ICU). VAP prevention is a multifaceted priority of the intensive care team, and can include the use of specialized artificial airways and heat-and-moisture exchangers (HME). Substantial evidence supports the use of endotracheal tubes (ETTs) that allow subglottic suctioning; silver-coated and antiseptic-impregnated ETTs; ETTs with thin-walled polyurethane cuffs; and HMEs, but these devices also can have adverse effects. Controversy still exists regarding the evidence, cost-effectiveness, and disadvantages and risks of these devices.

  2. Heat Treatment Optimization of Rutherford Cables for a 15 T Nb3Sn Dipole Demonstrator

    DOE PAGES

    Barzi, Emanuela; Bossert, Marianne; Field, Michael; ...

    2017-01-09

    FNAL has been developing a 15 T Nb3Sn dipole demonstrator for a future Very High Energy pp Collider based on an optimized 60-mm aperture 4-layer “cos-theta” coil. In order to increase magnet efficiency, we graded the coil by using two cables with same 15 mm width and different thicknesses made of two different Restacked Rod Process (RRP®) wires. Due to the non-uniform field distribution in dipole coils the maximum field in the inner coil will reach 15-16 T, whereas the maximum field in the outer coil is 12-13 T. In preparation for the 15 T dipole coil reaction, heat treatmentmore » studies were performed on strands extracted from these cables with the goal of achieving the best coil performance in the corresponding magnetic fields. Particularly, the effect of maximum temperature and time on the cable critical current was studied to take into account actual variations of these parameters during coil reaction. In parallel and in collaboration with OST, development was performed on optimizing Nb3Sn RRP® wire design and layout. Index Terms— Accelerator magnet, critical current density, Nb3Sn strand, Rutherford cable.« less

  3. Optimization of the ITER electron cyclotron equatorial launcher for improved heating and current drive functional capabilities

    SciTech Connect

    Farina, D.; Figini, L.; Henderson, M.; Saibene, G.

    2014-06-15

    The design of the ITER Electron Cyclotron Heating and Current Drive (EC H and CD) system has evolved in the last years both in goals and functionalities by considering an expanded range of applications. A large effort has been devoted to a better integration of the equatorial and the upper launchers, both from the point of view of the performance and of the design impact on the engineering constraints. However, from the analysis of the ECCD performance in two references H-mode scenarios at burn (the inductive H-mode and the advanced non-inductive scenario), it was clear that the EC power deposition was not optimal for steady-state applications in the plasma region around mid radius. An optimization study of the equatorial launcher is presented here aiming at removing this limitation of the EC system capabilities. Changing the steering of the equatorial launcher from toroidal to poloidal ensures EC power deposition out to the normalized toroidal radius ρ ≈ 0.6, and nearly doubles the EC driven current around mid radius, without significant performance degradation in the core plasma region. In addition to the improved performance, the proposed design change is able to relax some engineering design constraints on both launchers.

  4. Preparation of Reduced Iron Powders from Mill Scale with Microwave Heating: Optimization Using Response Surface Methodology

    NASA Astrophysics Data System (ADS)

    Ye, Qianxu; Zhu, Hongbo; Peng, Jinhui; Srinivasa Kannan, C.; Chen, Jian; Dai, Linqing; Liu, Peng

    2013-12-01

    Preparation of the reduced iron powder has been attempted with mill scale as the iron-bearing material and with wood charcoal as the reducing agent through microwave heating. The response surface methodology (RSM) is used to optimize the process conditions, with wood charcoal, process temperature, and holding time being the three process parameters. The regressed model equation eliminating the insignificant parameters through an analysis of variance (ANOVA) was used to optimize the process conditions. The optimum process parameters for the preparation of reduced iron powders have been identified to be the wood charcoal of 13.8 pct, a process temperature of 1391 K (1118 °C), and a holding time of 43 minutes. The optimum conditions resulted in reduced iron powders with a total iron content of 98.60 pct and a metallization ratio of 98.71 pct. X-ray fluorescence (XRF) was used to estimate the elemental contents of the reduced iron powder, which meets the specification of the HY100.23 first-class iron powder standard. Additionally X-ray diffraction (XRD), energy-dispersive spectroscopy (EDS), and scanning electron microscopy (SEM) analysis were performed and the results are compiled.

  5. Structural cost optimization of photovoltaic central power station modules and support structure

    NASA Technical Reports Server (NTRS)

    Sutton, P. D.; Stolte, W. J.; Marsh, R. O.

    1979-01-01

    The results of a comprehensive study of photovoltaic module structural support concepts for photovoltaic central power stations and their associated costs are presented. The objective of the study has been the identification of structural cost drivers. Parametric structural design and cost analyses of complete array systems consisting of modules, primary support structures, and foundations were performed. Area related module cost was found to be constant with design, size, and loading. A curved glass module concept was evaluated and found to have the potential to significantly reduce panel structural costs. Conclusions of the study are: array costs do not vary greatly among the designs evaluated; panel and array costs are strongly dependent on design loading; and the best support configuration is load dependent

  6. Particle Swarm Optimization and Varying Chemotactic Step-Size Bacterial Foraging Optimization Algorithms Based Dynamic Economic Dispatch with Non-smooth Fuel Cost Functions

    NASA Astrophysics Data System (ADS)

    Praveena, P.; Vaisakh, K.; Rama Mohana Rao, S.

    The Dynamic economic dispatch (DED) problem is an optimization problem with an objective to determine the optimal combination of power outputs for all generating units over a certain period of time in order to minimize the total fuel cost while satisfying dynamic operational constraints and load demand in each interval. Recently social foraging behavior of Escherichia coli bacteria has been explored to develop a novel algorithm for distributed optimization and control. The Bacterial Foraging Optimization Algorithm (BFOA) is currently gaining popularity in the community of researchers, for its effectiveness in solving certain difficult real-world optimization problems. This article comes up with a hybrid approach involving Particle Swarm Optimization (PSO) and BFO algorithms with varying chemo tactic step size for solving the DED problem of generating units considering valve-point effects. The proposed hybrid algorithm has been extensively compared with those methods reported in the literature. The new method is shown to be statistically significantly better on two test systems consisting of five and ten generating units.

  7. Optimization of the design and mode of operation of a QD laser for reducing the heat-to-bitrate ratio

    SciTech Connect

    Zhukov, A. E. Savelyev, A. V.; Maximov, M. V.; Kryzhanovskaya, N. V.; Gordeev, N. Yu.; Shernyakov, Yu. M.; Payusov, A. S.; Nadtochiy, A. M.; Zubov, F. I.; Korenev, V. V.

    2013-08-15

    Heat dissipation under the high-speed modulation of quantum dot edge-emitting lasers is considered. It is shown that, for a given laser diode, there is a bias current at which the heat-to-bitrate ratio is minimized. Moreover, there exists a certain optimal optical loss of the laser cavity at which the lowest heat-to-bitrate ratio is provided for any design of edge-emitting lasers that can be fabricated from an epitaxial structure. The heat-to-bitrate ratio and the corresponding bitrate are numerically calculated and analytical expressions are derived. It is demonstrated that the heat-to-bitrate ratio of quantum dot edge-emitting lasers can be less than 0.4 pJ/bit at a bitrate exceeding 10 Gbit/s.

  8. Heat pump employing optimal refrigerant compressor for low pressure ratio applications

    DOEpatents

    Ecker, Amir L.

    1982-01-01

    What is disclosed is a heat pump apparatus for conditioning a fluid characterized by a fluid handler for circulating the fluid in heat exchange relationship with a refrigerant fluid; two refrigerant heat exchangers; one for effecting the heat exchange with the fluid and a second refrigerant-heat exchange fluid heat exchanger for effecting a low pressure ratio of compression of the refrigerant; a rotary compressor for compressing the refrigerant with low power consumption at the low pressure ratio; at least one throttling valve connecting at the inlet side of heat exchanger in which liquid refrigerant is vaporized; a refrigerant circuit serially connecting the above elements; refrigerant in the circuit; a source of heat exchange fluid; heat exchange fluid circulating device and heat exchange fluid circuit for circulating the heat exchange fluid in heat exchange relationship with the refrigerant.

  9. Application of a multi-objective optimization method to provide least cost alternatives for NPS pollution control.

    PubMed

    Maringanti, Chetan; Chaubey, Indrajeet; Arabi, Mazdak; Engel, Bernard

    2011-09-01

    Nonpoint source (NPS) pollutants such as phosphorus, nitrogen, sediment, and pesticides are the foremost sources of water contamination in many of the water bodies in the Midwestern agricultural watersheds. This problem is expected to increase in the future with the increasing demand to provide corn as grain or stover for biofuel production. Best management practices (BMPs) have been proven to effectively reduce the NPS pollutant loads from agricultural areas. However, in a watershed with multiple farms and multiple BMPs feasible for implementation, it becomes a daunting task to choose a right combination of BMPs that provide maximum pollution reduction for least implementation costs. Multi-objective algorithms capable of searching from a large number of solutions are required to meet the given watershed management objectives. Genetic algorithms have been the most popular optimization algorithms for the BMP selection and placement. However, previous BMP optimization models did not study pesticide which is very commonly used in corn areas. Also, with corn stover being projected as a viable alternative for biofuel production there might be unintended consequences of the reduced residue in the corn fields on water quality. Therefore, there is a need to study the impact of different levels of residue management in combination with other BMPs at a watershed scale. In this research the following BMPs were selected for placement in the watershed: (a) residue management, (b) filter strips, (c) parallel terraces, (d) contour farming, and (e) tillage. We present a novel method of combing different NPS pollutants into a single objective function, which, along with the net costs, were used as the two objective functions during optimization. In this study we used BMP tool, a database that contains the pollution reduction and cost information of different BMPs under consideration which provides pollutant loads during optimization. The BMP optimization was performed using a NSGA

  10. Application of a Multi-Objective Optimization Method to Provide Least Cost Alternatives for NPS Pollution Control

    NASA Astrophysics Data System (ADS)

    Maringanti, Chetan; Chaubey, Indrajeet; Arabi, Mazdak; Engel, Bernard

    2011-09-01

    Nonpoint source (NPS) pollutants such as phosphorus, nitrogen, sediment, and pesticides are the foremost sources of water contamination in many of the water bodies in the Midwestern agricultural watersheds. This problem is expected to increase in the future with the increasing demand to provide corn as grain or stover for biofuel production. Best management practices (BMPs) have been proven to effectively reduce the NPS pollutant loads from agricultural areas. However, in a watershed with multiple farms and multiple BMPs feasible for implementation, it becomes a daunting task to choose a right combination of BMPs that provide maximum pollution reduction for least implementation costs. Multi-objective algorithms capable of searching from a large number of solutions are required to meet the given watershed management objectives. Genetic algorithms have been the most popular optimization algorithms for the BMP selection and placement. However, previous BMP optimization models did not study pesticide which is very commonly used in corn areas. Also, with corn stover being projected as a viable alternative for biofuel production there might be unintended consequences of the reduced residue in the corn fields on water quality. Therefore, there is a need to study the impact of different levels of residue management in combination with other BMPs at a watershed scale. In this research the following BMPs were selected for placement in the watershed: (a) residue management, (b) filter strips, (c) parallel terraces, (d) contour farming, and (e) tillage. We present a novel method of combing different NPS pollutants into a single objective function, which, along with the net costs, were used as the two objective functions during optimization. In this study we used BMP tool, a database that contains the pollution reduction and cost information of different BMPs under consideration which provides pollutant loads during optimization. The BMP optimization was performed using a NSGA

  11. A Low-Cost Thermistor Device for Measurements of Metabolic Heat in Yeast Cells in Suspension.

    ERIC Educational Resources Information Center

    Keeling, Richard P.

    1980-01-01

    Provides illustrated directions for the construction and use of a low-cost thermistor device. Attached to a servo-type millivolt chart recorder, the device will record minute temperature changes and will simulate data obtained from an oxygen polarograph. Includes results of experiments with baker's yeast. (Author/CS)

  12. Production of low-cost polyesters by microwaving heating of carboxylic acids and polyol blends

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Numerous issues such as price uncertainty, manufacturing costs, environmental disposal, and geo-political issues affect the petroleum-based polymer industry. As an alternative, increasing interest in the development of biodegradable non-petroleum-based polymers has risen steadily since the 1980s. Ho...

  13. HTGR high temperature process heat design and cost status report. Volume II. Appendices

    SciTech Connect

    1981-12-01

    Information is presented concerning the 850/sup 0/C IDC reactor vessel; primary cooling system; secondary helium system; steam generator; heat cycle evaluations for the 850/sup 0/C IDC plant; 950/sup 0/C DC reactor vessel; 950/sup 0/C DC steam generator; direct and indirect cycle reformers; methanation plant; thermochemical pipeline; methodology for screening candidate synfuel processes; ECCG process; project technical requirements; process gas explosion assessment; HTGR program economic guidelines; and vendor respones.

  14. Optimal Vehicle Design Using the Integrated System and Cost Modeling Tool Suite

    DTIC Science & Technology

    2010-08-01

    unmanned space vehicles and evaluate reusable vehicles with or without reentry , and parachute versus fly-back recovery. Launch vehicle reliability focuses...Laboratory (AFRL) that have been verified and validated. Some tools, such as the Program to Optimize Simulated Trajectories (POST), have their own...POST to optimize the trajectory . The framework will then loop through the sizing optimizer and POST until an optimum is found. The database module

  15. Optimization of Heat Exchangers with Dimpled Surfaces to Improve the Performance in Thermoelectric Generators Using a Kriging Model

    NASA Astrophysics Data System (ADS)

    Li, Shuai; Wang, Yiping; Wang, Tao; Yang, Xue; Deng, Yadong; Su, Chuqi

    2016-11-01

    Thermoelectric generators (TEGs) have become a topic of interest for vehicle exhaust energy recovery. Electrical power generation is deeply influenced by temperature differences, temperature uniformity and topological structures of TEGs. When the dimpled surfaces are adopted in heat exchangers, the heat transfer rates can be augmented with a minimal pressure drop. However, the temperature distribution shows a large gradient along the flow direction which has adverse effects on the power generation. In the current study, the heat exchanger performance was studied in a computational fluid dynamics (CFD) model. The dimple depth, dimple print diameter, and channel height were chosen as design variables. The objective function was defined as a combination of average temperature, temperature uniformity and pressure loss. The optimal Latin hypercube method was used to determine the experiment points as a method of design of the experiment in order to analyze the sensitivity of the design variables. A Kriging surrogate model was built and verified according to the database resulting from the CFD simulation. A multi-island genetic algorithm was used to optimize the structure in the heat exchanger based on the surrogate model. The results showed that the average temperature of the heat exchanger was most sensitive to the dimple depth. The pressure loss and temperature uniformity were most sensitive to the parameter of channel rear height, h 2. With an optimal design of channel structure, the temperature uniformity can be greatly improved compared with the initial exchanger, and the additional pressure loss also increased.

  16. A deterministic evaluation of heat stress mitigation and feed cost under climate change within the smallholder dairy sector.

    PubMed

    York, L; Heffernan, C; Rymer, C; Panda, N

    2016-12-28

    In the global South, dairying is often promoted as a means of poverty alleviation. Yet, under conditions of climate warming, little is known regarding the ability of small-scale dairy producers to maintain production and/or the robustness of possible adaptation options in meeting the challenges presented, particularly heat stress. The authors created a simple, deterministic model to explore the influence of breed and heat stress relief options on smallholder dairy farmers in Odisha, India. Breeds included indigenous Indian (non-descript), low-grade Jersey crossbreed and high-grade Jersey crossbreed. Relief strategies included providing shade, fanning and bathing. The impact of predicted critical global climate parameters, a 2°C and 4°C temperature rise were explored. A feed price scenario was modelled to illustrate the importance of feed in impact estimation. Feed costs were increased by 10% to 30%. Across the simulations, high-grade Jersey crossbreeds maintained higher milk yields, despite being the most sensitive to the negative effects of temperature. Low-capital relief strategies were the most effective at reducing heat stress impacts on household income. However, as feed costs increased the lower-grade Jersey crossbreed became the most profitable breed. The high-grade Jersey crossbreed was only marginally (4.64%) more profitable than the indigenous breed. The results demonstrate the importance of understanding the factors and practical trade-offs that underpin adaptation. The model also highlights the need for hot-climate dairying projects and programmes to consider animal genetic resources alongside environmentally sustainable adaptation measures for greatest poverty impact.

  17. Robust optimization for nonlinear time-delay dynamical system of dha regulon with cost sensitivity constraint in batch culture

    NASA Astrophysics Data System (ADS)

    Yuan, Jinlong; Zhang, Xu; Liu, Chongyang; Chang, Liang; Xie, Jun; Feng, Enmin; Yin, Hongchao; Xiu, Zhilong

    2016-09-01

    Time-delay dynamical systems, which depend on both the current state of the system and the state at delayed times, have been an active area of research in many real-world applications. In this paper, we consider a nonlinear time-delay dynamical system of dha-regulonwith unknown time-delays in batch culture of glycerol bioconversion to 1,3-propanediol induced by Klebsiella pneumonia. Some important properties and strong positive invariance are discussed. Because of the difficulty in accurately measuring the concentrations of intracellular substances and the absence of equilibrium points for the time-delay system, a quantitative biological robustness for the concentrations of intracellular substances is defined by penalizing a weighted sum of the expectation and variance of the relative deviation between system outputs before and after the time-delays are perturbed. Our goal is to determine optimal values of the time-delays. To this end, we formulate an optimization problem in which the time delays are decision variables and the cost function is to minimize the biological robustness. This optimization problem is subject to the time-delay system, parameter constraints, continuous state inequality constraints for ensuring that the concentrations of extracellular and intracellular substances lie within specified limits, a quality constraint to reflect operational requirements and a cost sensitivity constraint for ensuring that an acceptable level of the system performance is achieved. It is approximated as a sequence of nonlinear programming sub-problems through the application of constraint transcription and local smoothing approximation techniques. Due to the highly complex nature of this optimization problem, the computational cost is high. Thus, a parallel algorithm is proposed to solve these nonlinear programming sub-problems based on the filled function method. Finally, it is observed that the obtained optimal estimates for the time-delays are highly satisfactory

  18. Thermal modeling optimization and experimental validation for a single concentrator solar cell system with a heat sink

    NASA Astrophysics Data System (ADS)

    Cui, Min; Chen, Nuo-Fu; Deng, Jin-Xiang; Liu, Li-Ying

    2013-08-01

    A single concentrator solar cell model with a heat sink is established to simulate the thermal performance of the system by varying the number, height, and thickness of fins, the base thickness and thermal resistance of the thermal conductive adhesive. Influence disciplines of those parameters on temperatures of the solar cell and heat sink are obtained. With optimized number, height and thickness of fins, and the thickness values of base of 8, 1.4 cm, 1.5 mm, and 2 mm, the lowest temperatures of the solar cell and heat sink are 41.7 °C and 36.3 °C respectively. A concentrator solar cell prototype with a heat sink fabricated based on the simulation optimized structure is built. Outdoor temperatures of the prototype are tested. Temperatures of the solar cell and heat sink are stabilized with time continuing at about 37 °C-38 °C and 35 °C-36 °C respectively, slightly lower than the simulation results because of effects of the wind and cloud. Thus the simulation model enables to predict the thermal performance of the system, and the simulation results can be a reference for designing heat sinks in the field of single concentrator solar cells.

  19. Optimal Weighting of Costs and Probabilities in a Risky Motor Decision-Making Task Requires Experience

    ERIC Educational Resources Information Center

    Neyedli, Heather F.; Welsh, Timothy N.

    2013-01-01

    Previous research has revealed that people choose to aim toward an "optimal" endpoint when faced with a movement task with externally imposed payoffs. This optimal endpoint is modeled based on the magnitude of the payoffs and the probability of hitting the different payoff regions (endpoint variability). Endpoint selection, however, has only been…

  20. Non-fragile robust optimal guaranteed cost control of uncertain 2-D discrete state-delayed systems

    NASA Astrophysics Data System (ADS)

    Tandon, Akshata; Dhawan, Amit

    2016-10-01

    This paper is concerned with the problem of non-fragile robust optimal guaranteed cost control for a class of uncertain two-dimensional (2-D) discrete state-delayed systems described by the general model with norm-bounded uncertainties. Our attention is focused on the design of non-fragile state feedback controllers such that the resulting closed-loop system is asymptotically stable and the closed-loop cost function value is not more than a specified upper bound for all admissible parameter uncertainties and controller gain variations. A sufficient condition for the existence of such controllers is established under the linear matrix inequality framework. Moreover, a convex optimisation problem is proposed to select a non-fragile robust optimal guaranteed cost controller stabilising the 2-D discrete state-delayed system as well as achieving the least guaranteed cost for the resulting closed-loop system. The proposed method is compared with the previously reported criterion. Finally, illustrative examples are given to show the potential of the proposed technique.

  1. Heat Treatment Optimizations for Wind-and-React Bi-2212 Racetrack Coils

    NASA Astrophysics Data System (ADS)

    Godeke, A.; Cheng, D. W.; Dietderich, D. R.; Mentink, M. G. T.; Prestemon, S. O.; Sabbi, G. L.

    Lawrence Berkeley National Laboratory (LBNL) is developing Wind-and-React (W&R) Bi2Sr2CaCu2O8+δ (Bi-2212) accelerator magnet technology for insert coils, to surpass the intrinsic limitations of Nb-based magnets, and eventually develop hybrid systems that can approach 20 T dipole fields. The Bi-2212 technology is being developed in close collaboration with industry, and has been partly supported by the US Very High Field Superconducting Magnet Collaboration (VHFSMC). Steady improvements were made over the last several years, with coil HTS-SC08 reaching 2636 A, or about 85% of its witness sample critical current (Ic). Though this is still a factor 3 to 4 too low to be competitive with Nb-based materials, it is expected that the required Ic can be achieved through further conductor optimizations. Recent developments include the commissioning of infrastructure for the reaction of coils at LBNL. Earlier coils were fabricated and tested at LBNL, but were reacted at the wire manufacturer. We describe in detail the furnace calibrations and heat treatment optimizations that enable coil reactions at temperatures approaching 890°C with a homogeneity of ±1°C in a pure oxygen flow. We reacted two new coils at LBNL, and tested the performance of coil HTS-SC10 at 4.2 K in self-field using a superconducting transformer system. We find that its performance is consistent with witness samples, and comparable to coil HTS-SC08, which is an identical coil that was reacted at Oxford Instruments Superconductor Technology (OST), thereby validating the in-house reaction process

  2. Identifying and monitoring urban heat island in Bucharest using satellite time series and low cost meteorological sensors

    NASA Astrophysics Data System (ADS)

    Sandric, Ionut; Onose, Diana; Vanau, Gabriel; Ioja, Cristian

    2016-04-01

    The present study is focusing on the identification of urban heat island in Bucharest using both remote sensing products and low cost temperature sensors. The urban heat island in Bucharest was analyzed through a network of sensors located in 56 points (47 inside the administrative boundary of the city, 9 outside) 2009-2011. The network lost progressively its initial density, but was reformed during a new phase, 2013-2015. Time series satellite images from MODIS were intersected with the sensors for both phases. Statistical analysis were conducted to identify the temporal and spatial pattern of extreme temperatures in Bucharest. Several environmental factors like albedou, presence and absence of vegetation were used to fit a regression model between MODIS satellite products sensors in order to upscale the temperatures values recorded by MODIS For Bucharest, an important role for air temperature values in urban environments proved to have the local environmental conditions that leads to differences in air temperature at Bucharest city scale between 3-5 °C (both in the summer and in the winter). The UHI maps shows a good correlation with the presence of green areas. Differences in air temperature between higher tree density areas and isolated trees can reach much higher values, averages over 24 h periods still are in the 3-5 °C range The results have been obtained within the project UCLIMESA (Urban Heat Island Monitoring under Present and Future Climate), ongoing between 2013 and 2015 in the framework of the Programme for Research-DevelopmentInnovation for Space Technology and Advanced Research (STAR), administrated by the Romanian Space Agency Keywords: time series, urban heat island

  3. Modelling and optimization of transient processes in line focusing power plants with single-phase heat transfer medium

    NASA Astrophysics Data System (ADS)

    Noureldin, K.; González-Escalada, L. M.; Hirsch, T.; Nouri, B.; Pitz-Paal, R.

    2016-05-01

    A large number of commercial and research line focusing solar power plants are in operation and under development. Such plants include parabolic trough collectors (PTC) or linear Fresnel using thermal oil or molten salt as the heat transfer medium (HTM). However, the continuously varying and dynamic solar condition represent a big challenge for the plant control in order to optimize its power production and to keep the operation safe. A better understanding of the behaviour of such power plants under transient conditions will help reduce defocusing instances, improve field control, and hence, increase the energy yield and confidence in this new technology. Computational methods are very powerful and cost-effective tools to gain such understanding. However, most simulation models described in literature assume equal mass flow distributions among the parallel loops in the field or totally decouple the flow and thermal conditions. In this paper, a new numerical model to simulate a whole solar field with single-phase HTM is described. The proposed model consists of a hydraulic part and a thermal part that are coupled to account for the effect of the thermal condition of the field on the flow distribution among the parallel loops. The model is specifically designed for large line-focusing solar fields offering a high degree of flexibility in terms of layout, condition of the mirrors, and spatially resolved DNI data. Moreover, the model results have been compared to other simulation tools, as well as experimental and plant data, and the results show very good agreement. The model can provide more precise data to the control algorithms to improve the plant control. In addition, short-term and accurate spatially discretized DNI forecasts can be used as input to predict the field behaviour in-advance. In this paper, the hydraulic and thermal parts, as well as the coupling procedure, are described and some validation results and results of simulating an example field are

  4. Locally optimal control under unknown dynamics with learnt cost function: application to industrial robot positioning

    NASA Astrophysics Data System (ADS)

    Guérin, Joris; Gibaru, Olivier; Thiery, Stéphane; Nyiri, Eric

    2017-01-01

    Recent methods of Reinforcement Learning have enabled to solve difficult, high dimensional, robotic tasks under unknown dynamics using iterative Linear Quadratic Gaussian control theory. These algorithms are based on building a local time-varying linear model of the dynamics from data gathered through interaction with the environment. In such tasks, the cost function is often expressed directly in terms of the state and control variables so that it can be locally quadratized to run the algorithm. If the cost is expressed in terms of other variables, a model is required to compute the cost function from the variables manipulated. We propose a method to learn the cost function directly from the data, in the same way as for the dynamics. This way, the cost function can be defined in terms of any measurable quantity and thus can be chosen more appropriately for the task to be carried out. With our method, any sensor information can be used to design the cost function. We demonstrate the efficiency of this method through simulating, with the V-REP software, the learning of a Cartesian positioning task on several industrial robots with different characteristics. The robots are controlled in joint space and no model is provided a priori. Our results are compared with another model free technique, consisting in writing the cost function as a state variable.

  5. Investment and operating costs of binary cycle geothermal power plants

    NASA Technical Reports Server (NTRS)

    Holt, B.; Brugman, J.

    1974-01-01

    Typical investment and operating costs for geothermal power plants employing binary cycle technology and utilizing the heat energy in liquid-dominated reservoirs are discussed. These costs are developed as a function of reservoir temperature. The factors involved in optimizing plant design are discussed. A relationship between the value of electrical energy and the value of the heat energy in the reservoir is suggested.

  6. Maximum equivalent power output and performance optimization analysis of an alkaline fuel cell/heat-driven cycle hybrid system

    NASA Astrophysics Data System (ADS)

    Zhang, Xiuqin; Chen, Jincan

    A generic model of the hybrid system consisting of an alkaline fuel cell (AFC) and a heat-driven cycle, which may work as either a refrigerator or a heat pump, is originally established. On the basis of the models of AFCs and three-heat-reservoir cycles, the equivalent power output and efficiency of the hybrid system are obtained. The performance characteristic curves of the hybrid system are represented through numerical calculation. The maximum equivalent power output and efficiency of the hybrid system are determined. Problems concerning the optimal operation of the hybrid system are discussed. The effects of the main irreversible losses on the performance of the hybrid system are investigated in detail. It is important to note that the waste heat produced in the AFC can be readily used in such a hybrid cycle.

  7. Optimization on a three-level heat engine working with two noninteracting fermions in a one-dimensional box trap

    NASA Astrophysics Data System (ADS)

    Wang, Jianhui; He, Jizhou

    2012-02-01

    We setup a three-level heat engine model that works with two noninteracting fermions in a one-dimensional box trap. Besides two quantum adiabatic processes, the quantum heat engine cycle consists of two isoenergetic processes, along which the particles are coupled to energy baths at a high constant energy EH and a low constant energy EC, respectively. Based on the assumption that the potential wall moves at a very slow speed and there exists a heat leakage between two energy baths, we derive the expressions of the power output and the efficiency, and then obtain the optimization region for the heat engine cycle. Finally, we present a brief performance analysis of a Carnot engine between a hot and a cold bath at temperatures TH and TC, respectively. We demonstrate that under the same conditions, the efficiency η =1-(EC/EH) of the engine cycle is bounded from above the Carnot efficiency ηc=1-(TC/TH).

  8. Reducing the Cost of RLS: Waste Heat from Crop Production Can Be Used for Waste Processing

    NASA Technical Reports Server (NTRS)

    Lamparter, Richard; Flynn, Michael; Kliss, Mark (Technical Monitor)

    1997-01-01

    The applicability of plant-based life support systems has traditionally suffered from the limitations imposed by the high energy demand of controlled environment growth chambers. Theme types of systems are typically less than 2% efficient at converting electrical energy into biomass. The remaining 98% of supplied energy is converted to thermal energy. Traditionally this thermal energy is discharged to the ambient environment as waste heat. This paper describes an energy efficient plant-based life support system which has been designed for use at the Amundsen-Scott South Pole Station. At the South Pole energy is not lost to the environment. What is lost is the ability to extract useful work from it. The CELSS Antarctic Analog Program (CAAP) has developed a system which is designed to extract useful work from the waste thermal energy generated from plant growth lighting systems. In the CAAP system this energy is used to purify Station Sewage.

  9. Optimization of TCR and heat transport in group-IV multiple-quantum-well microbolometers

    NASA Astrophysics Data System (ADS)

    Morea, Matthew; Gu, Kevin; Savikhin, Victoria; Fenrich, Colleen S.; Pop, Eric; Harris, James S.

    2016-09-01

    Group-IV semiconductors have the opportunity to have an equivalent or better temperature coefficient of resistance (TCR) than other microbolometer thermistor materials. By using multiple-quantum-well (MQW) structures, their TCR values can be optimized due to a confinement of carriers. Through two approaches - an activation energy approximation and a custom Monte Carlo transfer matrix method - we simulated this effect for a combination of Group-IV semiconductors and their alloys (e.g., SiGe and GeSn) to find the highest possible TCR, while keeping in mind the critical thicknesses of such layers in a MQW epitaxial stack. We calculated the TCR for a critical-thickness-limited Ge0.8Sn0.2/Ge MQW device to be about -1.9 %/K. Although this TCR is lower than similar SiGe/Si MQW thermistors, GeSn offers possible advantages in terms of fabricating suspended devices with its interesting etch-stop properties shown in previous literature. Furthermore, using finite element modeling of heat transport, we looked at another key bolometer parameter: the thermal time constant. The dimensions of a suspended Ge microbolometer's supporting legs were fine-tuned for a target response time of 5 ms, incorporating estimations for the size effects of the nanowire-like legs on thermal conductivity.

  10. Ultrasound Thermometry for Optimizing heat Supply During a Hyperthermia Therapy of Cancer Tissue

    NASA Astrophysics Data System (ADS)

    Wolf, Mario; Rath, Katharina; Ruiz, Andrés Eduardo Ramos; Kühnicke, Elfgard

    Monitoring the temperature during a hyperthermia therapy allows optimizing the heat supply to destroy the cancer whereby the damage in the surrounding tissue is minimized. This contribution presents the fundamental research and current work to realize a locally resolved, noninvasive and intra-surgically applicable temperature measurement in tissue. This is realized by measuring the sound velocity locally resolved by an annular array, which allows noninvasive measurements although the observed tissue is not accessible from all directions. The method had been already qualified for fluids and analyses the echoes of moving scattering particles to obtain the time of flight to the focus of the transducer. As the parameters of the transducer are known the focus position (and thus the time of flight) can be calculated as a function of the sound velocity distribution of the propagation medium. Hence the measured time of flight allows determining the focus position and mean sound velocity simultaneously by means of this function. Varying the time lags of the signals for each element allows moving the focus and so measuring locally resolved. This contribution presents first ex-vivo measurements in tissue and thus proves the adaptability of this technique for tissue.

  11. Modeling the Optimal Heat Transfer Fluidization Velocity in Gas-Fluidized Beds

    NASA Astrophysics Data System (ADS)

    Predey, Thomas; Bougie, Jon; Goltsiker, Aleksandr

    2014-11-01

    Fluidized beds are vital to a wide range of industrial applications and are useful for studying two-phase flow. However, modeling the optimal heat transfer fluidization velocity (OHTFV) in such beds has remained difficult. Previous investigations have commonly taken one of two approaches. One such approach attempts to find a general scaling formula for homogeneous fluidized beds by taking a harmonic average between the terminal and minimum fluidization velocities. Modern approaches using computer simulations and a wide range of parameters are more commonly used in industry today, but are generally concerned with specific applications. We propose a third approach, taking into account the inhomogeneity of the fluidized bed system while limiting the input parameters to gas velocity and particle size. We use this approach to find a general formula for OHTFV that accounts for the collective behavior of the particles rather than focusing on each individual particle in the bed. We then compare this model to previous experimental results. This research is supported by the Loyola Undergraduate Research Opportunities Program.

  12. Areal density optimizations for heat-assisted magnetic recording of high-density media

    NASA Astrophysics Data System (ADS)

    Vogler, Christoph; Abert, Claas; Bruckner, Florian; Suess, Dieter; Praetorius, Dirk

    2016-06-01

    Heat-assisted magnetic recording (HAMR) is hoped to be the future recording technique for high-density storage devices. Nevertheless, there exist several realization strategies. With a coarse-grained Landau-Lifshitz-Bloch model, we investigate in detail the benefits and disadvantages of a continuous and pulsed laser spot recording of shingled and conventional bit-patterned media. Additionally, we compare single-phase grains and bits having a bilayer structure with graded Curie temperature, consisting of a hard magnetic layer with high TC and a soft magnetic one with low TC, respectively. To describe the whole write process as realistically as possible, a distribution of the grain sizes and Curie temperatures, a displacement jitter of the head, and the bit positions are considered. For all these cases, we calculate bit error rates of various grain patterns, temperatures, and write head positions to optimize the achievable areal storage density. Within our analysis, shingled HAMR with a continuous laser pulse moving over the medium reaches the best results and thus has the highest potential to become the next-generation storage device.

  13. Cost-optimal design of dry cooling towers through mathematical programming techniques

    SciTech Connect

    Buys, J.D.; Kroeger, D.G. )

    1989-05-01

    The Constrained Variable Metric Algorithm is chosen to minimize the objective function (cost) in the design of a natural draft dry cooling tower. An existing cooling system design that has specific performance characteristics under prescribed operating conditions is selected as a reference unit. By changing design variables, but not exceeding prescribed constraints, a more cost-effective design is achieved. The influence of various parameters, and the sensitivity of the objective function to these parameters, are evaluated.

  14. cost and benefits optimization model for fault-tolerant aircraft electronic systems

    NASA Technical Reports Server (NTRS)

    1983-01-01

    The factors involved in economic assessment of fault tolerant systems (FTS) and fault tolerant flight control systems (FTFCS) are discussed. Algorithms for optimization and economic analysis of FTFCS are documented.

  15. User manual for AQUASTOR: a computer model for cost analysis of aquifer thermal energy storage coupled with district heating or cooling systems. Volume I. Main text

    SciTech Connect

    Huber, H.D.; Brown, D.R.; Reilly, R.W.

    1982-04-01

    A computer model called AQUASTOR was developed for calculating the cost of district heating (cooling) using thermal energy supplied by an aquifer thermal energy storage (ATES) system. The AQUASTOR model can simulate ATES district heating systems using stored hot water or ATES district cooling systems using stored chilled water. AQUASTOR simulates the complete ATES district heating (cooling) system, which consists of two principal parts: the ATES supply system and the district heating (cooling) distribution system. The supply system submodel calculates the life-cycle cost of thermal energy supplied to the distribution system by simulating the technical design and cash flows for the exploration, development, and operation of the ATES supply system. The distribution system submodel calculates the life-cycle cost of heat (chill) delivered by the distribution system to the end-users by simulating the technical design and cash flows for the construction and operation of the distribution system. The model combines the technical characteristics of the supply system and the technical characteristics of the distribution system with financial and tax conditions for the entities operating the two systems into one techno-economic model. This provides the flexibility to individually or collectively evaluate the impact of different economic and technical parameters, assumptions, and uncertainties on the cost of providing district heating (cooling) with an ATES system. This volume contains the main text, including introduction, program description, input data instruction, a description of the output, and Appendix H, which contains the indices for supply input parameters, distribution input parameters, and AQUASTOR subroutines.

  16. Design of an optimal promoter involved in the heat-induced transcriptional pathway in Arabidopsis, soybean, rice and maize.

    PubMed

    Maruyama, Kyonoshin; Ogata, Takuya; Kanamori, Norihito; Yoshiwara, Kyouko; Goto, Shingo; Yamamoto, Yoshiharu Y; Tokoro, Yuko; Noda, Chihiro; Takaki, Yuta; Urawa, Hiroko; Iuchi, Satoshi; Urano, Kaoru; Yoshida, Takuhiro; Sakurai, Tetsuya; Kojima, Mikiko; Sakakibara, Hitoshi; Shinozaki, Kazuo; Yamaguchi-Shinozaki, Kazuko

    2017-02-01

    Interactions between heat shock (HS) factors (HSFs) and heat shock response elements (HSEs) are important during the heat shock response (HSR) of flora and fauna. Moreover, plant HSFs that are involved in heat stress are also involved in abiotic stresses such as dehydration and cold as well as development, cell differentiation and proliferation. Because the specific combination of HSFs and HSEs involved in plants under heat stress remains unclear, the mechanism of their interaction has not yet been utilized in molecular breeding of plants for climate change. For the study reported herein, we compared the sequences of HS-inducible genes and their promoters in Arabidopsis, soybean, rice and maize and then designed an optimal HS-inducible promoter. Our analyses suggest that, for the four species, the abscisic acid-independent, HSE/HSF-dependent transcriptional pathway plays a major role in HS-inducible gene expression. We found that an 18-bp sequence that includes the HSE has an important role in the HSR, and that those sequences could be classified as representative of monocotyledons or dicotyledons. With the HS-inducible promoter designed based on our bioinformatic predictions, we were able to develop an optimal HS-specific inducible promoter for seedlings or single cells in roots. These findings demonstrate the utility of our HS-specific inducible promoter, which we expect will contribute to molecular breeding efforts and cell-targeted gene expression in specific plant tissues.

  17. Cost optimization of a real-time GIS-based management system for hazardous waste transportation.

    PubMed

    Zhu, Yun; Lin, Che-Jen; Zhong, Yilong; Zhou, Qing; Lin, Che-Jen; Chen, Chunyi

    2010-08-01

    In this paper, the design and cost analysis of a real-time, geographical information system (GIS) based management system for hazardous waste transportation are described. The implementation of such a system can effectively prevent illegal dumping and perform emergency responses during the transportation of hazardous wastes. A case study was conducted in Guangzhou, China to build a small-scale, real-time management system for waste transportation. Two alternatives were evaluated in terms of system capability and cost structure. Alternative I was the building of a complete real-time monitoring and management system in a governing agency; whereas alternative II was the combination of the existing management framework with a commercial Telematics service to achieve the desired level of monitoring and management. The technological framework under consideration included locating transportation vehicles using a global positioning system (GPS), exchanging vehicle location data via the Internet and Intranet, managing hazardous waste transportation using a government management system and responding to emergencies during transportation. Analysis of the cost structure showed that alternative II lowered the capital and operation cost by 38 and 56% in comparison with alternative I. It is demonstrated that efficient management can be achieved through integration of the existing technological components with additional cost benefits being achieved by streamlined software interfacing.

  18. Optimal insemination and replacement decisions to minimize the cost of pathogen-specific clinical mastitis in dairy cows.

    PubMed

    Cha, E; Kristensen, A R; Hertl, J A; Schukken, Y H; Tauer, L W; Welcome, F L; Gröhn, Y T

    2014-01-01

    Mastitis is a serious production-limiting disease, with effects on milk yield, milk quality, and conception rate, and an increase in the risk of mortality and culling. The objective of this study was 2-fold: (1) to develop an economic optimization model that incorporates all the different types of pathogens that cause clinical mastitis (CM) categorized into 8 classes of culture results, and account for whether the CM was a first, second, or third case in the current lactation and whether the cow had a previous case or cases of CM in the preceding lactation; and (2) to develop this decision model to be versatile enough to add additional pathogens, diseases, or other cow characteristics as more information becomes available without significant alterations to the basic structure of the model. The model provides economically optimal decisions depending on the individual characteristics of the cow and the specific pathogen causing CM. The net returns for the basic herd scenario (with all CM included) were $507/cow per year, where the incidence of CM (cases per 100 cow-years) was 35.6, of which 91.8% of cases were recommended for treatment under an optimal replacement policy. The cost per case of CM was $216.11. The CM cases comprised (incidences, %) Staphylococcus spp. (1.6), Staphylococcus aureus (1.8), Streptococcus spp. (6.9), Escherichia coli (8.1), Klebsiella spp. (2.2), other treated cases (e.g., Pseudomonas; 1.1), other not treated cases (e.g., Trueperella pyogenes; 1.2), and negative culture cases (12.7). The average cost per case, even under optimal decisions, was greatest for Klebsiella spp. ($477), followed by E. coli ($361), other treated cases ($297), and other not treated cases ($280). This was followed by the gram-positive pathogens; among these, the greatest cost per case was due to Staph. aureus ($266), followed by Streptococcus spp. ($174) and Staphylococcus spp. ($135); negative culture had the lowest cost ($115). The model recommended treatment for

  19. Cost-Effective Fabrication Routes for the Production of Quantum Well Structures and Recovery of Waste Heat from Heavy Duty Trucks

    SciTech Connect

    Willigan, Rhonda

    2009-09-30

    The primary objectives of Phase I were: (a) carry out cost, performance and system level models, (b) quantify the cost benefits of cathodic arc and heterogeneous nanocomposites over sputtered material, (c) evaluate the expected power output of the proposed thermoelectric materials and predict the efficiency and power output of an integrated TE module, (d) define market acceptance criteria by engaging Caterpillar's truck OEMs, potential customers and dealers and identify high-level criteria for a waste heat thermoelectric generator (TEG), (e) identify potential TEG concepts, and (f) establish cost/kWatt targets as well as a breakdown of subsystem component cost targets for the commercially viable TEG.

  20. Neutral buoyancy is optimal to minimize the cost of transport in horizontally swimming seals.

    PubMed

    Sato, Katsufumi; Aoki, Kagari; Watanabe, Yuuki Y; Miller, Patrick J O

    2013-01-01

    Flying and terrestrial animals should spend energy to move while supporting their weight against gravity. On the other hand, supported by buoyancy, aquatic animals can minimize the energy cost for supporting their body weight and neutral buoyancy has been considered advantageous for aquatic animals. However, some studies suggested that aquatic animals might use non-neutral buoyancy for gliding and thereby save energy cost for locomotion. We manipulated the body density of seals using detachable weights and floats, and compared stroke efforts of horizontally swimming seals under natural conditions using animal-borne recorders. The results indicated that seals had smaller stroke efforts to swim a given speed when they were closer to neutral buoyancy. We conclude that neutral buoyancy is likely the best body density to minimize the cost of transport in horizontal swimming by seals.

  1. Optimizing Ready-to-Use Therapeutic Foods for Protein Quality, Cost, and Acceptability.

    PubMed

    Weber, Jacklyn; Callaghan, Meghan

    2016-03-01

    This article describes current research on the development of alternative ready-to-use therapeutic foods (RUTFs) in the treatment of severe acute malnutrition. An innovative and versatile linear programming tool has been developed to facilitate the creation of therapeutic formulas that are determined acceptable on multiple levels: costs, ingredient acceptability, availability and stability, nutrient requirements, and personal preferences. The formulas are analyzed for ease of production by Washington University team members and for organoleptic properties acceptability to target populations. In the future, RUTF products that are cost-effective, acceptable, sustainable, and widely available will become a reality.

  2. ANALYSIS OF SAFETY RELIEF VALVE PROOF TEST DATA TO OPTIMIZE LIFECYCLE MAINTENANCE COSTS

    SciTech Connect

    Gross, Robert; Harris, Stephen

    2007-08-01

    Proof test results were analyzed and compared with a proposed life cycle curve or hazard function and the limit of useful life. Relief valve proof testing procedures, statistical modeling, data collection processes, and time-in-service trends are presented. The resulting analysis of test data allows for the estimation of the PFD. Extended maintenance intervals to the limit of useful life as well as methodologies and practices for improving relief valve performance and reliability are discussed. A generic cost-benefit analysis and an expected life cycle cost reduction concludes that $90 million maintenance dollars might be avoided for a population of 3000 valves over 20 years.

  3. Multi-parameter optimization tool for low-cost commercial fuselage crown designs

    NASA Technical Reports Server (NTRS)

    Zabinsky, Zelda; Tuttle, Mark; Graesser, Douglas; Kim, Gun-In; Hatcher, Darrin; Swanson, Gary; Ilcewicz, Larry

    1991-01-01

    The work in progress for developing a methodology and software tool to aid in the optimal design of composite structures is discussed. The methodology is being developed to take advantage of the ability to tailor the composite material in conjunction with the design of the structure. The composites optimization design software UWCODA was found to be very successful in preliminary testing and early experience. UWCODA is a composites design code that uses a number of plies and fiber angles as design variables, employs maximum strain failure criteria for objective function and additional constraints, includes Boeing design tools for stiffened panels, and includes stiffener geometry in the design variables.

  4. Optimize Resources and Help Reduce Cost of Ownership with Dell[TM] Systems Management

    ERIC Educational Resources Information Center

    Technology & Learning, 2008

    2008-01-01

    Maintaining secure, convenient administration of the PC system environment can be a significant drain on resources. Deskside visits can greatly increase the cost of supporting a large number of computers. Even simple tasks, such as tracking inventory or updating software, quickly become expensive when they require physically visiting every…

  5. Teleconferencing: Cost optimization of satellite and ground systems for continuing progressional education and medical services

    NASA Technical Reports Server (NTRS)

    Dunn, D.; Lusignan, B.

    1972-01-01

    A set of analytical capabilities that are needed to assess the role satellite communications technology will play in public and other services was developed. It is user oriented in that it starts from descriptions of user demand and develops the ability to estimate the cost of satisfying that demand with the lowest cost communications system. To ensure that the analysis could cope with the complexities of the real users, two services were chosen as examples, continuing professional education and medical services. Telecommunications costs are effected greatly by demographic factors, involving distribution of users in urban areas and distances between towns in rural regions. For this reason the analytical tools were exercised on sample locations. San Jose, California and Denver, Colorado were used to represent an urban area and the Rocky Mountain states were used to represent a rural region. In assessing the range of satellite system costs, two example coverage areas were considered, one appropriate to cover the contiguous forty-eight states, a second appropriate to cover about one-third that area.

  6. SOLAR HEATING OF TANK BOTTOMS Application of Solar Heating to Asphaltic and Parrafinic Oils Reducing Fuel Costs and Greenhouse Gases Due to Use of Natural Gas and Propane

    SciTech Connect

    Eugene A. Fritzler

    2005-09-01

    The sale of crude oil requires that the crude meet product specifications for BS&W, temperature, pour point and API gravity. The physical characteristics of the crude such as pour point and viscosity effect the efficient loading, transport, and unloading of the crude oil. In many cases, the crude oil has either a very high paraffin content or asphalt content which will require either hot oiling or the addition of diluents to the crude oil to reduce the viscosity and the pour point of the oil allowing the crude oil to be readily loaded on to the transport. Marginal wells are significantly impacted by the cost of preheating the oil to an appropriate temperature to allow for ease of transport. Highly paraffinic and asphaltic oils exist throughout the D-J basin and generally require pretreatment during cold months prior to sales. The current study addresses the use of solar energy to heat tank bottoms and improves the overall efficiency and operational reliability of stripper wells.

  7. Optimal planning and processing of the results of tests for hydraulic and heat losses in heat systems

    NASA Astrophysics Data System (ADS)

    Grebneva, O. A.; Novitskii, N. N.

    2014-10-01

    The approaches and algorithms proposed in the present study form the basis of a novel technology for identifying heat systems. This technology consists in actively influencing the conditions that determine the accuracy of estimation of the actual parameters of real systems whose knowledge renders it possible to solve efficiently the problems of modernization, checkout, and centralized control. The method presupposes a sequential planning strategy: each experiment is conducted with due consideration of the data obtained after the results of the preceding one are processed. The procedure of planning the test environment, positioning the measuring equipment, conducting the experiment, and processing and analyzing its results is repeated at each step in the proposed method.

  8. Screening and life-cycle cost models for new pulverized-coal heating plants: An integrated computer-based module for the central heating plant economic evaluation program (CHPECON). Final report

    SciTech Connect

    Sheng, R.; Kinast, J.A.; Biederman, R.; Blazek, C.F.; Lin, M.C.

    1995-07-01

    Public Law 99-190 requires the Department of Defense (DOD) to increase the use of coal for steam generation, but DOD also has an obligation to use the most economical fuel. In support of the coal conversion effort, the U.S. Army Construction Engineering Research Laboratories (USACERL) has been tasked to develop a series of screening and life-cycle cost models to determine when and where specific coal-combustion technologies can economically be implemented in Army central heating plants. This report documents a pulverized coal-fired boiler analysis model, part of the USACERL-developed Central Heating Plant Economics model (CHPECON). The model is divided into two parts. A preliminary screening model contains options for evaluating new heating plants and cogeneration facilities fueled with pulverized coal, as well as the previous options. A cost model uses the entries provided by the screening model to provide a conceptual facility design, capital (installed) costs of the facility, operation and maintenance costs over the life of the facility, and life-cycle costs. Using these numbers the model produces a summary value for the total life-cycle cost of the plant, and a levelized cost of service.

  9. Optimizing the preventive maintenance scheduling by genetic algorithm based on cost and reliability in National Iranian Drilling Company

    NASA Astrophysics Data System (ADS)

    Javanmard, Habibollah; Koraeizadeh, Abd al-Wahhab

    2016-06-01

    The present research aims at predicting the required activities for preventive maintenance in terms of equipment optimal cost and reliability. The research sample includes all offshore drilling equipment of FATH 59 Derrick Site affiliated with National Iranian Drilling Company. Regarding the method, the research uses a field methodology and in terms of its objectives, it is classified as an applied research. Some of the data are extracted from the documents available in the equipment and maintenance department of FATH 59 Derrick site, and other needed data are resulted from experts' estimates through genetic algorithm method. The research result is provided as the prediction of downtimes, costs, and reliability in a predetermined time interval. The findings of the method are applicable for all manufacturing and non-manufacturing equipment.

  10. Is local participation always optimal for sustainable action? The costs of consensus-building in Local Agenda 21.

    PubMed

    Brandt, Urs Steiner; Svendsen, Gert Tinggaard

    2013-11-15

    Is local participation always optimal for sustainable action? Here, Local Agenda 21 is a relevant case as it broadly calls for consensus-building among stakeholders. Consensus-building is, however, costly. We show that the costs of making local decisions are likely to rapidly exceed the benefits. Why? Because as the number of participants grows, the more likely it is that the group will include individuals who have an extreme position and are unwilling to make compromises. Thus, the net gain of self-organization should be compared with those of its alternatives, for example voting, market-solutions, or not making any choices at all. Even though the informational value of meetings may be helpful to policy makers, the model shows that it also decreases as the number of participants increase. Overall, the result is a thought provoking scenario for Local Agenda 21 as it highlights the risk of less sustainable action in the future.

  11. Identifying Cost-Effective Water Resources Management Strategies: Watershed Management Optimization Support Tool (WMOST)

    EPA Science Inventory

    The Watershed Management Optimization Support Tool (WMOST) is a public-domain software application designed to aid decision makers with integrated water resources management. The tool allows water resource managers and planners to screen a wide-range of management practices for c...

  12. Cost and benefits design optimization model for fault tolerant flight control systems

    NASA Technical Reports Server (NTRS)

    Rose, J.

    1982-01-01

    Requirements and specifications for a method of optimizing the design of fault-tolerant flight control systems are provided. Algorithms that could be used for developing new and modifying existing computer programs are also provided, with recommendations for follow-on work.

  13. Optimization of HDR brachytherapy dose distributions using linear programming with penalty costs

    SciTech Connect

    Alterovitz, Ron; Lessard, Etienne; Pouliot, Jean; Hsu, I-Chow Joe; O'Brien, James F.; Goldberg, Ken

    2006-11-15

    Prostate cancer is increasingly treated with high-dose-rate (HDR) brachytherapy, a type of radiotherapy in which a radioactive source is guided through catheters temporarily implanted in the prostate. Clinicians must set dwell times for the source inside the catheters so the resulting dose distribution minimizes deviation from dose prescriptions that conform to patient-specific anatomy. The primary contribution of this paper is to take the well-established dwell times optimization problem defined by Inverse Planning by Simulated Annealing (IPSA) developed at UCSF and exactly formulate it as a linear programming (LP) problem. Because LP problems can be solved exactly and deterministically, this formulation provides strong performance guarantees: one can rapidly find the dwell times solution that globally minimizes IPSA's objective function for any patient case and clinical criteria parameters. For a sample of 20 prostates with volume ranging from 23 to 103 cc, the new LP method optimized dwell times in less than 15 s per case on a standard PC. The dwell times solutions currently being obtained clinically using simulated annealing (SA), a probabilistic method, were quantitatively compared to the mathematically optimal solutions obtained using the LP method. The LP method resulted in significantly improved objective function values compared to SA (P=1.54x10{sup -7}), but none of the dosimetric indices indicated a statistically significant difference (P<0.01). The results indicate that solutions generated by the current version of IPSA are clinically equivalent to the mathematically optimal solutions.

  14. Fabrication of transparent ZnS ceramic by optimizing the heating rate in spark plasma sintering process

    NASA Astrophysics Data System (ADS)

    Chen, Yuanzhi; Zhang, Le; Zhang, Jian; Liu, Peng; Zhou, Tianyuan; Zhang, Hongxiang; Gong, Dongmei; Tang, Dingyuan; Shen, Deyuan

    2015-12-01

    Transparent ZnS ceramics were fabricated at a lower temperature (840 °C) by optimizing the heating rate in the spark plasma sintering (SPS) process. The phase composition, microstructure and the optical properties of the ceramics were investigated by XRD, SEM and FTIR. Under the optimized heating rate of 5 °C/min, ZnS ceramics with the best optical qualities was obtained, and the transmittance reached above 60% in the range of 5.0-12.0 μm and it was higher than 40% in the range of 2.0-3.0 μm. Meanwhile, the content of hexagonal phase was controlled to be lower than 7.5%.

  15. Optimizing management of the condensing heat and cooling of gases compression in oxy block using of a genetic algorithm

    NASA Astrophysics Data System (ADS)

    Brzęczek, Mateusz; Bartela, Łukasz

    2013-12-01

    This paper presents the parameters of the reference oxy combustion block operating with supercritical steam parameters, equipped with an air separation unit and a carbon dioxide capture and compression installation. The possibility to recover the heat in the analyzed power plant is discussed. The decision variables and the thermodynamic functions for the optimization algorithm were identified. The principles of operation of genetic algorithm and methodology of conducted calculations are presented. The sensitivity analysis was performed for the best solutions to determine the effects of the selected variables on the power and efficiency of the unit. Optimization of the heat recovery from the air separation unit, flue gas condition and CO2 capture and compression installation using genetic algorithm was designed to replace the low-pressure section of the regenerative water heaters of steam cycle in analyzed unit. The result was to increase the power and efficiency of the entire power plant.

  16. Optimality of Upper-Arm Reaching Trajectories Based on the Expected Value of the Metabolic Energy Cost.

    PubMed

    Taniai, Yoshiaki; Nishii, Jun

    2015-08-01

    When we move our body to perform a movement task, our central nervous system selects a movement trajectory from an infinite number of possible trajectories under constraints that have been acquired through evolution and learning. Minimization of the energy cost has been suggested as a potential candidate for a constraint determining locomotor parameters, such as stride frequency and stride length; however, other constraints have been proposed for a human upper-arm reaching task. In this study, we examined whether the minimum metabolic energy cost model can also explain the characteristics of the upper-arm reaching trajectories. Our results show that the optimal trajectory that minimizes the expected value of energy cost under the effect of signal-dependent noise on motor commands expresses not only the characteristics of reaching movements of typical speed but also those of slower movements. These results suggest that minimization of the energy cost would be a basic constraint not only in locomotion but also in upper-arm reaching.

  17. Developing an Onboard Traffic-Aware Flight Optimization Capability for Near-Term Low-Cost Implementation

    NASA Technical Reports Server (NTRS)

    Wing, David J.; Ballin, Mark G.; Koczo, Stefan, Jr.; Vivona, Robert A.; Henderson, Jeffrey M.

    2013-01-01

    The concept of Traffic Aware Strategic Aircrew Requests (TASAR) combines Automatic Dependent Surveillance Broadcast (ADS-B) IN and airborne automation to enable user-optimal in-flight trajectory replanning and to increase the likelihood of Air Traffic Control (ATC) approval for the resulting trajectory change request. TASAR is designed as a near-term application to improve flight efficiency or other user-desired attributes of the flight while not impacting and potentially benefiting ATC. Previous work has indicated the potential for significant benefits for each TASAR-equipped aircraft. This paper will discuss the approach to minimizing TASAR's cost for implementation and accelerating readiness for near-term implementation.

  18. Optimization of water use and cost of electricity for an MEA carbon capture process, January 26, 2012

    SciTech Connect

    Eslick, J.; Miller, D.

    2012-01-01

    DOE goals are: 90% CO{sub 2} capture, Less than 30% increase in COE, and to reduce water use by 70% at 50% cost of dry cooling. Objectives are: (1) Develop detailed models of supercritical power plant, MEA carbon capture process, CO{sub 2} compression; and (2) Optimize process for conflicting goals of minimizing water use and COE CO{sub 2} capture greatly increases COE and water use, power gen. 1/3 of fresh water use, and water scarcity is increasing.

  19. The optimization of fin-tube heat exchanger with longitudinal vortex generators using response surface approximation and genetic algorithm

    NASA Astrophysics Data System (ADS)

    Wu, Xuehong; Liu, DanDan; Zhao, Min; Lu, YanLi; Song, Xiaoyong

    2016-09-01

    Delta winglet works better than other vortex generators in improving the performance of fin-tube heat exchangers. In this paper, Response Surface Approximation is used to study the effects of the fin pitch, the ratio of the longitudinal tube pitch to transverse tube pitch, the ratio of both sides V 1 , V h of delta winglets and the attack angle of delta winglets on the performance of fin-tube heat exchanger. Firstly, Twenty-nine numerical group experiments including five times repeated experiments at the central point are conducted. Then, the analyses of variable (ANOVA) and regression are performed to verify the accuracy of the polynomial coefficients. Finally, the optimization of the fin-tube heat exchanger using the Genetic Algorithm is conducted and the best performance of j/f (1/3) is found to be 0.07945, which is consistent with the numerical result.

  20. Fuzzy Stochastic Optimal Guaranteed Cost Control of Bio-Economic Singular Markovian Jump Systems.

    PubMed

    Li, Li; Zhang, Qingling; Zhu, Baoyan

    2015-11-01

    This paper establishes a bio-economic singular Markovian jump model by considering the price of the commodity as a Markov chain. The controller is designed for this system such that its biomass achieves the specified range with the least cost in a finite-time. Firstly, this system is described by Takagi-Sugeno fuzzy model. Secondly, a new design method of fuzzy state-feedback controllers is presented to ensure not only the regularity, nonimpulse, and stochastic singular finite-time boundedness of this kind of systems, but also an upper bound achieved for the cost function in the form of strict linear matrix inequalities. Finally, two examples including a practical example of eel seedling breeding are given to illustrate the merit and usability of the approach proposed in this paper.

  1. A Real Options Approach to Quantity and Cost Optimization for Lifetime and Bridge Buys of Parts

    DTIC Science & Technology

    2015-12-01

    December 2015 This research was par t ia l ly sponsored by the Naval Postg raduate School . A Real Options Approach to Quantity and Cost...and bridge buys, which are used to manage part discontinuance (i.e., obsolescence) during the support of critical systems are simple in concept, the...Acquisition Research Program under Grant No. N00244-14-1-0060 and the Office of the Secretary of Defense. The views expressed in this report do not

  2. Single and Multiresponse Adaptive Design of Experiments with Application to Design Optimization of Novel Heat Exchangers

    DTIC Science & Technology

    2009-01-01

    performance evaluation method for air- cooled heat exchangers in which conventional 3D Computational Fluid Dynamics (CFD) simulation is replaced with a 2D...parts to this research thrust. First, is a new multi-level performance evaluation method for air- cooled heat exchangers in which conventional 3D...performance of a novel air- cooled heat exchanger such as tube-fin or microchannels . The novel aspect generally refers to a new fin design or a tube

  3. Modelling of the District Heating System's Operation

    NASA Astrophysics Data System (ADS)

    Vigants, Girts; Blumberga, Dagnija; Vīgants, Ģirts; Blumberga, Dagnija

    2011-01-01

    The development of a district heating systems calculation model means improvement in the energy efficiency of a district heating system, which makes it possible to reduce the heat losses, thus positively affecting the tariffs on thermal energy. In this paper, a universal approach is considered, based on which the optimal flow and temperature conditions in a district heating system network could be calculated. The optimality is determined by the least operational costs. The developed calculation model has been tested on the Ludza district heating system based on the technical parameters of this system.

  4. Transport Studies Enabling Efficiency Optimization of Cost-Competitive Fuel Cell Stacks (aka AURORA: Areal Use and Reactant Optimization at Rated Amperage)

    SciTech Connect

    Conti, Amedeo; Dross, Robert

    2013-12-06

    Hydrogen fuel cells are recognized as one of the most viable solutions for mobility in the 21st century; however, there are technical challenges that must be addressed before the technology can become available for mass production. One of the most demanding aspects is the costs of present-day fuel cells which are prohibitively high for the majority of envisioned markets. The fuel cell community recognizes two major drivers to an effective cost reduction: (1) decreasing the noble metals content, and (2) increasing the power density in order to reduce the number of cells needed to achieve a specified power level. To date, the majority of development work aimed at increasing the value metric (i.e. W/mg-Pt) has focused on the reduction of precious metal loadings, and this important work continues. Efforts to increase power density have been limited by two main factors: (1) performance limitations associated with mass transport barriers, and (2) the historical prioritization of efficiency over cost. This program is driven by commercialization imperatives, and challenges both of these factors. The premise of this Program, supported by proprietary cost modeling by Nuvera, is that DOE 2015 cost targets can be met by simultaneously exceeding DOE 2015 targets for Platinum loadings (using materials with less than 0.2 mg-Pt/cm2) and MEA power density (operating at higher than 1.0 Watt/cm2). The approach of this program is to combine Nuvera’s stack technology, which has demonstrated the ability to operate stably at high current densities (> 1.5 A/cm2), with low Platinum loading MEAs developed by Johnson Matthey in order to maximize Pt specific power density and reduce stack cost. A predictive performance model developed by PSU/UTK is central to the program allowing the team to study the physics and optimize materials/conditions specific to low Pt loading electrodes and ultra-high current density and operation.

  5. Evaluation of Missed Energy Saving Opportunity Based on Illinois Home Performance Program Field Data: Homeowner Selected Upgrades Versus Cost-Optimized Solutions

    SciTech Connect

    Yee, S.; Milby, M.; Baker, J.

    2014-06-01

    Expanding on previous research by PARR, this study compares measure packages installed during 800 Illinois Home Performance with ENERGY STAR® (IHP) residential retrofits to those recommended as cost-optimal by Building Energy Optimization (BEopt) modeling software. In previous research, cost-optimal measure packages were identified for 15 Chicagoland single family housing archetypes. In the present study, 800 IHP homes are first matched to one of these 15 housing groups, and then the average measures being installed in each housing group are modeled using BEopt to estimate energy savings. For most housing groups, the differences between recommended and installed measure packages is substantial. By comparing actual IHP retrofit measures to BEopt-recommended cost-optimal measures, missed savings opportunities are identified in some housing groups; also, valuable information is obtained regarding housing groups where IHP achieves greater savings than BEopt-modeled, cost-optimal recommendations. Additionally, a measure-level sensitivity analysis conducted for one housing group reveals which measures may be contributing the most to gas and electric savings. Overall, the study finds not only that for some housing groups, the average IHP retrofit results in more energy savings than would result from cost-optimal, BEopt recommended measure packages, but also that linking home categorization to standardized retrofit measure packages provides an opportunity to streamline the process for single family home energy retrofits and maximize both energy savings and cost effectiveness.

  6. Evaluation of Missed Energy Saving Opportunity Based on Illinois Home Performance Program Field Data: Homeowner Selected Upgrades Versus Cost-Optimized Solutions

    SciTech Connect

    Yee, S.; Milby, M.; Baker, J.

    2014-06-01

    Expanding on previous research by PARR, this study compares measure packages installed during 800 Illinois Home Performance with ENERGY STAR(R) (IHP) residential retrofits to those recommended as cost-optimal by Building Energy Optimization (BEopt) modeling software. In previous research, cost-optimal measure packages were identified for fifteen Chicagoland single family housing archetypes, called housing groups. In the present study, 800 IHP homes are first matched to one of these fifteen housing groups, and then the average measures being installed in each housing group are modeled using BEopt to estimate energy savings. For most housing groups, the differences between recommended and installed measure packages is substantial. By comparing actual IHP retrofit measures to BEopt-recommended cost-optimal measures, missed savings opportunities are identified in some housing groups; also, valuable information is obtained regarding housing groups where IHP achieves greater savings than BEopt-modeled, cost-optimal recommendations. Additionally, a measure-level sensitivity analysis conducted for one housing group reveals which measures may be contributing the most to gas and electric savings. Overall, the study finds not only that for some housing groups, the average IHP retrofit results in more energy savings than would result from cost-optimal, BEopt recommended measure packages, but also that linking home categorization to standardized retrofit measure packages provides an opportunity to streamline the process for single family home energy retrofits and maximize both energy savings and cost-effectiveness.

  7. Evaluation of Missed Energy Saving Opportunity Based on Illinois Home Performance Program Field Data: Homeowner Selected Upgrades vs. Cost-Optimized Solutions; Chicago, Illinois (Fact Sheet)

    SciTech Connect

    Not Available

    2014-07-01

    Expanding on previous research by PARR, this study compares measure packages installed during 800 Illinois Home Performance with ENERGY STAR (IHP) residential retrofits to those recommended as cost-optimal by Building Energy Optimization (BEopt) modeling software. In previous research, cost-optimal measure packages were identified for fifteen Chicagoland single family housing archetypes, called housing groups. In the present study, 800 IHP homes are first matched to one of these fifteen housing groups, and then the average measures being installed in each housing group are modeled using BEopt to estimate energy savings. For most housing groups, the differences between recommended and installed measure packages is substantial. By comparing actual IHP retrofit measures to BEopt-recommended cost-optimal measures, missed savings opportunities are identified in some housing groups; also, valuable information is obtained regarding housing groups where IHP achieves greater savings than BEopt-modeled, cost-optimal recommendations. Additionally, a measure-level sensitivity analysis conducted for one housing group reveals which measures may be contributing the most to gas and electric savings. Overall, the study finds not only that for some housing groups, the average IHP retrofit results in more energy savings than would result from cost-optimal, BEopt-recommended measure packages, but also that linking home categorization to standardized retrofit measure packages provides an opportunity to streamline the process for single family home energy retrofits and maximize both energy savings and cost-effectiveness.

  8. Advanced steam power plant concepts with optimized life-cycle costs: A new approach for maximum customer benefit

    SciTech Connect

    Seiter, C.

    1998-07-01

    The use of coal power generation applications is currently enjoying a renaissance. New highly efficient and cost-effective plant concepts together with environmental protection technologies are the main factors in this development. In addition, coal is available on the world market at attractive prices and in many places it is more readily available than gas. At the economical leading edge, standard power plant concepts have been developed to meet the requirements of emerging power markets. These concepts incorporate the high technological state-of-the-art and are designed to achieve lowest life-cycle costs. Low capital cost, fuel costs and operating costs in combination with shortest lead times are the main assets that make these plants attractive especially for IPPs and Developers. Other aspects of these comprehensive concepts include turnkey construction and the willingness to participate in BOO/BOT projects. One of the various examples of such a concept, the 2 x 610-MW Paiton Private Power Project Phase II in Indonesia, is described in this paper. At the technological leading edge, Siemens has always made a major contribution and was pacemaker for new developments in steam power plant technology. Modern coal-fired steam power plants use computer-optimized process and plant design as well as advanced materials, and achieve efficiencies exceeding 45%. One excellent example of this high technology is the world's largest lignite-fired steam power plant Schwarze Pumpe in Germany, which is equipped with two 800 MW Siemens steam turbine generators with supercritical steam parameters. The world's largest 50-Hz single-shaft turbine generator with supercritical steam parameters rated at 1025 MW for the Niederaussem lignite-fired steam power plant in Germany is a further example of the sophisticated Siemens steam turbine technology and sets a new benchmark in this field.

  9. User manual for AQUASTOR: a computer model for cost analysis of aquifer thermal-energy storage oupled with district-heating or cooling systems. Volume II. Appendices

    SciTech Connect

    Huber, H.D.; Brown, D.R.; Reilly, R.W.

    1982-04-01

    A computer model called AQUASTOR was developed for calculating the cost of district heating (cooling) using thermal energy supplied by an aquifer thermal energy storage (ATES) system. the AQUASTOR Model can simulate ATES district heating systems using stored hot water or ATES district cooling systems using stored chilled water. AQUASTOR simulates the complete ATES district heating (cooling) system, which consists of two prinicpal parts: the ATES supply system and the district heating (cooling) distribution system. The supply system submodel calculates the life-cycle cost of thermal energy supplied to the distribution system by simulating the technical design and cash flows for the exploration, development, and operation of the ATES supply system. The distribution system submodel calculates the life-cycle cost of heat (chill) delivered by the distribution system to the end-users by simulating the technical design and cash flows for the construction and operation of the distribution system. The model combines the technical characteristics of the supply system and the technical characteristics of the distribution system with financial and tax conditions for the entities operating the two systems into one techno-economic model. This provides the flexibility to individually or collectively evaluate the impact of different economic and technical parameters, assumptions, and uncertainties on the cost of providing district heating (cooling) with an ATES system. This volume contains all the appendices, including supply and distribution system cost equations and models, descriptions of predefined residential districts, key equations for the cooling degree-hour methodology, a listing of the sample case output, and appendix H, which contains the indices for supply input parameters, distribution input parameters, and AQUASTOR subroutines.

  10. Optimization of low-cost medium for very high gravity ethanol fermentations by Saccharomyces cerevisiae using statistical experimental designs.

    PubMed

    Pereira, Francisco B; Guimarães, Pedro M R; Teixeira, José A; Domingues, Lucília

    2010-10-01

    Statistical experimental designs were used to develop a medium based on corn steep liquor (CSL) and other low-cost nutrient sources for high-performance very high gravity (VHG) ethanol fermentations by Saccharomyces cerevisiae. The critical nutrients were initially selected according to a Plackett-Burman design and the optimized medium composition (44.3 g/L CSL; 2.3 g/L urea; 3.8 g/L MgSO₄·7H₂O; 0.03 g/L CuSO₄·5H₂O) for maximum ethanol production by the laboratory strain CEN.PK 113-7D was obtained by response surface methodology, based on a three-level four-factor Box-Behnken design. The optimization process resulted in significantly enhanced final ethanol titre, productivity and yeast viability in batch VHG fermentations (up to 330 g/L glucose) with CEN.PK113-7D and with industrial strain PE-2, which is used for bio-ethanol production in Brazil. Strain PE-2 was able to produce 18.6±0.5% (v/v) ethanol with a corresponding productivity of 2.4±0.1g/L/h. This study provides valuable insights into cost-effective nutritional supplementation of industrial fuel ethanol VHG fermentations.

  11. Tailoring the optimal control cost function to a desired output: application to minimizing phase errors in short broadband excitation pulses.

    PubMed

    Skinner, Thomas E; Reiss, Timo O; Luy, Burkhard; Khaneja, Navin; Glaser, Steffen J

    2005-01-01

    The de facto standard cost function has been used heretofore to characterize the performance of pulses designed using optimal control theory. The freedom to choose new, creative quality factors designed for specific purposes is demonstrated. While the methodology has more general applicability, its utility is illustrated by comparison to a consistently chosen example--broadband excitation. The resulting pulses are limited to the same maximum RF amplitude used previously and tolerate the same variation in RF homogeneity deemed relevant for standard high-resolution NMR probes. Design criteria are unchanged: transformation of I(z)--> I(x) over resonance offsets of +/-20 kHz and RF variability of +/-5%, with a peak RF amplitude equal to 17.5 kHz. However, the new cost effectively trades a small increase in residual z magnetization for improved phase in the transverse plane. Compared to previous broadband excitation by optimized pulses (BEBOP), significantly shorter pulses are achievable, with only marginally reduced performance. Simulations transform I(z) to greater than 0.98 I(x), with phase deviations of the final magnetization less than 2 degrees, over the targeted ranges of resonance offset and RF variability. Experimental performance is in excellent agreement with the simulations.

  12. Optimization of the Process of Carburizing and Heat Treatment of Low-Carbon Martensitic Steels

    NASA Astrophysics Data System (ADS)

    Ivanov, A. S.; Greben'kov, S. K.; Bogdanova, M. V.

    2016-05-01

    Steel 24Kh2G2NMFB is studied after carburizing and different heat treatments. The hardness and microhardness of the surface layer and of the matrix are measured. The content of retained austenite is determined by the method of x-ray diffraction analysis. Heat treatment modes improving the structure of the surface layer after carburizing are suggested.

  13. Predicting the critical heat flux in concentric-tube open thermosiphon: a method based on support vector machine optimized by chaotic particle swarm optimization algorithm

    NASA Astrophysics Data System (ADS)

    Cai, Jiejin

    2012-08-01

    This study presents a method based on support vector machine (SVM) optimized by chaotic particle swarm optimization algorithm (CPSO) for the prediction of the critical heat flux (CHF) in concentric-tube open thermosiphon. In this process, the parameters C, ɛ and δ2 of SVM have been determined by the CPSO. As for a comparision, the traditional back propagation neural network (BPNN), radial basis function neural network (RBFNN), general regression neural network (GRNN) are also used to predict the CHF for the same experimental results under a variety of operating conditions. The MER and RMSE of SVM-CPSO model are about 45% of the BPNN model, about 60% of the RBFNN model, and about 80% of GRNN model. The simulation results demonstrate that the SVM-CPSO method can get better accuracy.

  14. Low cost fuel cell diffusion layer configured for optimized anode water management

    DOEpatents

    Owejan, Jon P; Nicotera, Paul D; Mench, Matthew M; Evans, Robert E

    2013-08-27

    A fuel cell comprises a cathode gas diffusion layer, a cathode catalyst layer, an anode gas diffusion layer, an anode catalyst layer and an electrolyte. The diffusion resistance of the anode gas diffusion layer when operated with anode fuel is higher than the diffusion resistance of the cathode gas diffusion layer. The anode gas diffusion layer may comprise filler particles having in-plane platelet geometries and be made of lower cost materials and manufacturing processes than currently available commercial carbon fiber substrates. The diffusion resistance difference between the anode gas diffusion layer and the cathode gas diffusion layer may allow for passive water balance control.

  15. A low-cost, high-yield fabrication method for producing optimized biomimetic dry adhesives

    NASA Astrophysics Data System (ADS)

    Sameoto, D.; Menon, C.

    2009-11-01

    We present a low-cost, large-scale method of fabricating biomimetic dry adhesives. This process is useful because it uses all photosensitive polymers with minimum fabrication costs or complexity to produce molds for silicone-based dry adhesives. A thick-film lift-off process is used to define molds using AZ 9260 photoresist, with a slow acting, deep UV sensitive material, PMGI, used as both an adhesion promoter for the AZ 9260 photoresist and as an undercutting material to produce mushroom-shaped fibers. The benefits to this process are ease of fabrication, wide range of potential layer thicknesses, no special surface treatment requirements to demold silicone adhesives and easy stripping of the full mold if process failure does occur. Sylgard® 184 silicone is used to cast full sheets of biomimetic dry adhesives off 4" diameter wafers, and different fiber geometries are tested for normal adhesion properties. Additionally, failure modes of the adhesive during fabrication are noted and strategies for avoiding these failures are discussed. We use this fabrication method to produce different fiber geometries with varying cap diameters and test them for normal adhesion strengths. The results indicate that the cap diameters relative to post diameters for mushroom-shaped fibers dominate the adhesion properties.

  16. Minimum Cost Multi-way Data Association for Optimizing Multitarget Tracking of Interacting Objects

    SciTech Connect

    Park, Chiwoo; Woehl, Taylor J.; Evans, James E.; Browning, Nigel D.

    2015-03-01

    This paper presents a general formulation for a minimum cost data association problem which associates data features via one-to-one, m-to-one and one-to-n links with minimum total cost of the links. A motivating example is a problem of tracking multiple interacting nanoparticles imaged on video frames, where particles can aggregate into one particle or a particle can be split into multiple particles. Many existing multitarget tracking methods are capable of tracking non-interacting targets or tracking interacting targets of restricted degrees of interactions. The proposed formulation solves a multitarget tracking problem for general degrees of inter-object interactions. The formulation is in the form of a binary integer programming problem. We propose a polynomial time solution approach that can obtain a good relaxation solution of the binary integer programming, so the approach can be applied for multitarget tracking problems of a moderate size (for hundreds of targets over tens of time frames). The resulting solution is always integral and obtains a better duality gap than the simple linear relaxation solution of the corresponding problem. The proposed method was validated through applications to simulated multitarget tracking problems and a real multitarget tracking problem.

  17. Cost-effective approach to ethanol production and optimization by response surface methodology.

    PubMed

    Uncu, Oya Nihan; Cekmecelioglu, Deniz

    2011-04-01

    Food wastes disposed from residential and industrial kitchens have gained attention as a substrate in microbial fermentations to reduce product costs. In this study, the potential of simultaneously hydrolyzing and subsequently fermenting the mixed carbohydrate components of kitchen wastes were assessed and the effects of solid load, inoculum volume of baker's yeast, and fermentation time on ethanol production were evaluated by response surface methodology (RSM). The enzymatic hydrolysis process was complete within 6h. Fermentation experiments were conducted at pH 4.5, a temperature of 30°C, and agitated at 150 rpm without adding the traditional fermentation nutrients. The statistical analysis of the model developed by RSM suggested that linear effects of solid load, inoculum volume, and fermentation time and the quadratic effects of inoculum volume and fermentation time were significant (P<0.05). The verification experiments indicated that the developed model could be successfully used to predict ethanol concentration at >90% accuracy. An optimum ethanol concentration of 32.2g/l giving a yield of 0.40g/g, comparable to yields reported to date, was suggested by the model with 20% solid load, 8.9% inoculum volume, and 58.8h of fermentation. The results indicated that the production costs can be lowered to a large extent by using kitchen wastes having multiple carbohydrate components and eliminating the use of traditional fermentation nutrients from the recipe.

  18. Optimal Materials and Deposition Technique Lead to Cost-Effective Solar Cell with Best-Ever Conversion Efficiency (Fact Sheet)

    SciTech Connect

    Not Available

    2012-07-01

    This fact sheet describes how the SJ3 solar cell was invented, explains how the technology works, and why it won an R&D 100 Award. Based on NREL and Solar Junction technology, the commercial SJ3 concentrator solar cell - with 43.5% conversion efficiency at 418 suns - uses a lattice-matched multijunction architecture that has near-term potential for cells with {approx}50% efficiency. Multijunction solar cells have higher conversion efficiencies than any other type of solar cell. But developers of utility-scale and space applications crave even better efficiencies at lower costs to be both cost-effective and able to meet the demand for power. The SJ3 multijunction cell, developed by Solar Junction with assistance from foundational technological advances by the National Renewable Energy Laboratory, has the highest efficiency to date - almost 2% absolute more than the current industry standard multijunction cell-yet at a comparable cost. So what did it take to create this cell having 43.5% efficiency at 418-sun concentration? A combination of materials with carefully designed properties, a manufacturing technique allowing precise control, and an optimized device design.

  19. Optimal isolation control strategies and cost-effectiveness analysis of a two-strain avian influenza model.

    PubMed

    Agusto, F B

    2013-09-01

    The most important and effective measures against disease outbreaks in the absence of valid medicines or vaccine are quarantine and isolation strategies. In this paper optimal control theory is applied to a system of ordinary differential equation describing a two-strain avian influenza transmission via the Pontryagin's Maximum Principle. To this end, a pair of control variables representing the isolation strategies for individuals with avian and mutant strains were incorporated into the transmission model. The infection averted ratio (IAR) and the incremental cost-effectiveness ratio (ICER) were calculated to investigate the cost-effectiveness of all possible combinations of the control strategies. The simulation results show that the implementation of the combination strategy during the epidemic is the most cost-effective strategy for avian influenza transmission. This is followed by the control strategy involving isolation of individuals with the mutant strain. Also observed was the fact that low mutating and more virulent virus results in an increased control effort of isolating individuals with the avian strain; and high mutating with more virulent virus results in increased efforts in isolating individuals with the mutant strain.

  20. The cost of model reference adaptive control - Analysis, experiments, and optimization

    NASA Technical Reports Server (NTRS)

    Messer, R. S.; Haftka, R. T.; Cudney, H. H.

    1993-01-01

    In this paper the performance of Model Reference Adaptive Control (MRAC) is studied in numerical simulations and verified experimentally with the objective of understanding how differences between the plant and the reference model affect the control effort. MRAC is applied analytically and experimentally to a single degree of freedom system and analytically to a MIMO system with controlled differences between the model and the plant. It is shown that the control effort is sensitive to differences between the plant and the reference model. The effects of increased damping in the reference model are considered, and it is shown that requiring the controller to provide increased damping actually decreases the required control effort when differences between the plant and reference model exist. This result is useful because one of the first attempts to counteract the increased control effort due to differences between the plant and reference model might be to require less damping, however, this would actually increase the control effort. Optimization of weighting matrices is shown to help reduce the increase in required control effort. However, it was found that eventually the optimization resulted in a design that required an extremely high sampling rate for successful realization.

  1. A low-cost culture medium for the production of Nannochloropsis gaditana biomass optimized for aquaculture.

    PubMed

    Camacho-Rodríguez, J; Cerón-García, M C; González-López, C V; Fernández-Sevilla, J M; Contreras-Gómez, A; Molina-Grima, E

    2013-09-01

    Nannochloropsis gaditana is a microalga with a high nutritional value and a protein and polyunsaturated fatty acid (PUFA) content that makes it interesting as a feed in aquaculture. To maximize its productivity and nutritional value in large-scale culture, a well-known commercial medium was optimized to the most favorable nutrient level using commercial fertilizers. Optimal growth conditions were obtained in the alternative fertilizer-based medium at a nitrogen concentration of 11.3 mM, a phosphorus concentration of 0.16 mM, and a micronutrient concentration of 30 μL L(-1). This alternative medium allowed to obtain a biomass concentration similar to that achieved when using the commercial formula but with a reduction in Cu, Fe, and Mo content of 71%, 89%, and 99%, respectively. A maximum biomass productivity of 0.51 g L(-1) d(-1) was obtained. The eicosapentaenoic acid and protein contents of the biomass were 2.84% and 44% of dry weight, respectively.

  2. The Cost-Optimal Distribution of Wind and Solar Generation Facilities in a Simplified Highly Renewable European Power System

    NASA Astrophysics Data System (ADS)

    Kies, Alexander; von Bremen, Lüder; Schyska, Bruno; Chattopadhyay, Kabitri; Lorenz, Elke; Heinemann, Detlev

    2016-04-01

    The transition of the European power system from fossil generation towards renewable sources is driven by different reasons like decarbonisation and sustainability. Renewable power sources like wind and solar have, due to their weather dependency, fluctuating feed-in profiles, which make their system integration a difficult task. To overcome this issue, several solutions have been investigated in the past like the optimal mix of wind and PV [1], the extension of the transmission grid or storages [2]. In this work, the optimal distribution of wind turbines and solar modules in Europe is investigated. For this purpose, feed-in data with an hourly temporal resolution and a spatial resolution of 7 km covering Europe for the renewable sources wind, photovoltaics and hydro was used. Together with historical load data and a transmission model , a simplified pan-European power power system was simulated. Under cost assumptions of [3] the levelized cost of electricity (LCOE) for this simplified system consisting of generation, consumption, transmission and backup units is calculated. With respect to the LCOE, the optimal distribution of generation facilities in Europe is derived. It is shown, that by optimal placement of renewable generation facilities the LCOE can be reduced by more than 10% compared to a meta study scenario [4] and a self-sufficient scenario (every country produces on average as much from renewable sources as it consumes). This is mainly caused by a shift of generation facilities towards highly suitable locations, reduced backup and increased transmission need. The results of the optimization will be shown and implications for the extension of renewable shares in the European power mix will be discussed. The work is part of the RESTORE 2050 project (Wuppertal Institute, Next Energy, University of Oldenburg), that is financed by the Federal Ministry of Education and Research (BMBF, Fkz. 03SFF0439A). [1] Kies, A. et al.: Kies, Alexander, et al

  3. Global optimal vaccination in the SIR model: properties of the value function and application to cost-effectiveness analysis.

    PubMed

    Laguzet, Laetitia; Turinici, Gabriel

    2015-05-01

    This work focuses on optimal vaccination policies for an Susceptible-Infected-Recovered (SIR) model; the impact of the disease is minimized with respect to the vaccination strategy. The problem is formulated as an optimal control problem and we show that the value function is the unique viscosity solution of an Hamilton-Jacobi-Bellman (HJB) equation. This allows to find the best vaccination policy. At odds with existing literature, it is seen that the value function is not always smooth (sometimes only Lipschitz) and the optimal vaccination policies are not unique. Moreover we rigorously analyze the situation when vaccination can be modeled as instantaneous (with respect to the time evolution of the epidemic) and identify the global optimum solutions. Numerical applications illustrate the theoretical results. In addition the pertussis vaccination in adults is considered from two perspectives: first the maximization of DALY averted in presence of vaccine side-effects; then the impact of the herd immunity on the cost-effectiveness analysis is discussed on a concrete example.

  4. Techno-economic analysis of using corn stover to supply heat and power to a corn ethanol plant - Part 1: Cost of feedstock supply logistics

    SciTech Connect

    Sokhansanj, Shahabaddine; Mani, Sudhagar; Togore, Sam; Turhollow Jr, Anthony F

    2010-01-01

    Supply of corn stover to produce heat and power for a typical 170 dam3 dry mill ethanol plant is proposed. The corn ethanol plant requires 5.6 MW of electricity and 52.3 MW of process heat, which creates the annual stover demand of as much as 140 Gg. The corn stover supply system consists of collection, preprocessing, transportation and on-site fuel storage and preparation to produce heat and power for the ethanol plant. Economics of the entire supply system was conducted using the Integrated Biomass Supply Analysis and Logistics (IBSAL) simulation model. Corn stover was delivered in three formats (square bales, dry chops and pellets) to the combined heat and power plant. Delivered cost of biomass ready to be burned was calculated at 73 $ Mg-1 for bales, 86 $ Mg-1 for pellets and 84 $ Mg-1 for field chopped biomass. Among the three formats of stover supply systems, delivered cost of pelleted biomass was the highest due to high pelleting cost. Bulk transport of biomass in the form of chops and pellets can provide a promising future biomass supply logistic system in the US, if the costs of pelleting and transport are minimized.

  5. Optimization and Thermoeconomics Research of a Large Reclaimed Water Source Heat Pump System

    PubMed Central

    Zhang, Zi-ping; Du, Fang-hui

    2013-01-01

    This work describes a large reclaimed water source heat pump system (RWSHPS) and elaborates on the composition of the system and its design principles. According to the characteristics of the reclaimed water and taking into account the initial investment, the project is divided into two stages: the first stage adopts distributed heat pump heating system and the second adopts the combination of centralized and decentralized systems. We analyze the heating capacity of the RWSHPS, when the phase II project is completed, the system can provide hydronic heating water with the supply and return water temperature of 55°C/15°C and meet the hydronic heating demand of 8 million square meters of residential buildings. We make a thermal economics analysis by using Thermal Economics theory on RWSHPS and gas boiler system, it is known that the RWSHPS has more advantages, compared with the gas boiler heating system; both its thermal efficiency and economic efficiency are relatively high. It provides a reference for future applications of the RWSHPS. PMID:24089607

  6. Optimization and thermoeconomics research of a large reclaimed water source heat pump system.

    PubMed

    Zhang, Zi-ping; Du, Fang-hui

    2013-01-01

    This work describes a large reclaimed water source heat pump system (RWSHPS) and elaborates on the composition of the system and its design principles. According to the characteristics of the reclaimed water and taking into account the initial investment, the project is divided into two stages: the first stage adopts distributed heat pump heating system and the second adopts the combination of centralized and decentralized systems. We analyze the heating capacity of the RWSHPS, when the phase II project is completed, the system can provide hydronic heating water with the supply and return water temperature of 55°C/15°C and meet the hydronic heating demand of 8 million square meters of residential buildings. We make a thermal economics analysis by using Thermal Economics theory on RWSHPS and gas boiler system, it is known that the RWSHPS has more advantages, compared with the gas boiler heating system; both its thermal efficiency and economic efficiency are relatively high. It provides a reference for future applications of the RWSHPS.

  7. Optimization of protocol design: a path to efficient, lower cost clinical trial execution

    PubMed Central

    Malikova, Marina A

    2016-01-01

    Managing clinical trials requires strategic planning and efficient execution. In order to achieve a timely delivery of important clinical trials’ outcomes, it is useful to establish standardized trial management guidelines and develop robust scoring methodology for evaluation of study protocol complexity. This review will explore the challenges clinical teams face in developing protocols to ensure that the right patients are enrolled and the right data are collected to demonstrate that a drug is safe and efficacious, while managing study costs and study complexity based on proposed comprehensive scoring model. Key factors to consider when developing protocols and techniques to minimize complexity will be discussed. A methodology to identify processes at planning phase, approaches to increase fiscal return and mitigate fiscal compliance risk for clinical trials will be addressed. PMID:28031939

  8. Optimization and economic evaluation of industrial gas production and combined heat and power generation from gasification of corn stover and distillers grains.

    PubMed

    Kumar, Ajay; Demirel, Yasar; Jones, David D; Hanna, Milford A

    2010-05-01

    Thermochemical gasification is one of the most promising technologies for converting biomass into power, fuels and chemicals. The objectives of this study were to maximize the net energy efficiency for biomass gasification, and to estimate the cost of producing industrial gas and combined heat and power (CHP) at a feedrate of 2000kg/h. Aspen Plus-based model for gasification was combined with a CHP generation model, and optimized using corn stover and dried distillers grains with solubles (DDGS) as the biomass feedstocks. The cold gas efficiencies for gas production were 57% and 52%, respectively, for corn stover and DDGS. The selling price of gas was estimated to be $11.49 and $13.08/GJ, respectively, for corn stover and DDGS. For CHP generation, the electrical and net efficiencies were as high as 37% and 88%, respectively, for corn stover and 34% and 78%, respectively, for DDGS. The selling price of electricity was estimated to be $0.1351 and $0.1287/kWh for corn stover and DDGS, respectively. Overall, high net energy efficiencies for gas and CHP production from biomass gasification can be achieved with optimized processing conditions. However, the economical feasibility of these conversion processes will depend on the relative local prices of fossil fuels.

  9. Reduction of fine particle emissions from wood combustion with optimized condensing heat exchangers.

    PubMed

    Gröhn, Arto; Suonmaa, Valtteri; Auvinen, Ari; Lehtinen, Kari E J; Jokiniemi, Jorma

    2009-08-15

    In this study, we designed and built a condensing heat exchanger capable of simultaneous fine particle emission reduction and waste heat recovery. The deposition mechanisms inside the heat exchanger prototype were maximized using a computer model which was later compared to actual measurements. The main deposition mechanisms were diffusio- and thermophoresis which have previously been examined in similar conditions only separately. The obtained removal efficiency in the experiments was measured in the total number concentration and ranged between 26 and 40% for the given pellet stove and the heat exchanger. Size distributions and number concentrations were measured with a TSI Fast mobility particle sizer (FMPS). The computer model predicts that there exists a specific upper limit for thermo- and diffusiophoretic deposition for each temperature and water vapor concentration in the flue gas.

  10. Thermal Optimization of the Heat Exchanger in an Automotive Exhaust-Based Thermoelectric Generator

    NASA Astrophysics Data System (ADS)

    Deng, Y. D.; Liu, X.; Chen, S.; Tong, N. Q.

    2013-07-01

    Recent advances in thermoelectric technologies have made exhaust-based thermoelectric generators (TEGs) promising to recover waste heat. The thermal performance of the heat exchanger in exhaust-based TEGs is studied in this work. In terms of interface temperature and thermal uniformity, the thermal characteristics of heat exchangers with different internal structures, lengths, and materials are discussed. Following computational fluid dynamics simulations, infrared experiments are carried out on a high-performance production engine with a dynamometer. Simulation and experimental results show that a plate-shaped heat exchanger made of brass with fishbone-shaped internal structure and length of 600 mm achieves a relatively ideal thermal performance, which is practically helpful to enhance the thermal performance of the TEG.

  11. Heat treatment of NiCrFe alloy to optimize resistance to intergrannular stress corrosion

    DOEpatents

    Steeves, Arthur F.; Bibb, Albert E.

    1984-01-01

    A process of producing a NiCrFe alloy having a high resistance to stress corrosion cracking comprising heating a NiCrFe alloy to a temperature sufficient to enable the carbon present in the alloy body in the form of carbide deposits to enter into solution, rapidly cool the alloy body, and heat the cooled body to a temperature between 1100.degree. to 1500.degree. F. for about 1 to 30 hours.

  12. Heat treatment of NiCrFe alloy 600 to optimize resistance to intergranular stress corrosion

    DOEpatents

    Steeves, A.F.; Bibb, A.E.

    A process of producing a NiCrFe alloy having a high resistance to stress corrosion cracking comprises heating a NiCrFe alloy to a temperature sufficient to enable the carbon present in the alloy body in the form of carbide deposits to enter into solution, rapidly cooling the alloy body, and heating the cooled body to a temperature between 1100 to 1500/sup 0/F for about 1 to 30 hours.

  13. On a Time-Optimal Control Problem Associated with the Heat Exchange Process

    SciTech Connect

    Albeverio, Sergio Alimov, Shavkat

    2008-02-15

    The initial-boundary problem for the heat conduction equation inside a bounded domain is considered. It is supposed that on the boundary of this domain the heat exchange according to Newton's law takes place. The control parameter is equal to the magnitude of output of hot or cold air and is defined on a given part of the boundary. An estimate of the minimal time for achieving the given average temperature is found.

  14. Drying process optimization for an API solvate using heat transfer model of an agitated filter dryer.

    PubMed

    Nere, Nandkishor K; Allen, Kimberley C; Marek, James C; Bordawekar, Shailendra V

    2012-10-01

    Drying an early stage active pharmaceutical ingredient candidate required excessively long cycle times in a pilot plant agitated filter dryer. The key to faster drying is to ensure sufficient heat transfer and minimize mass transfer limitations. Designing the right mixing protocol is of utmost importance to achieve efficient heat transfer. To this order, a composite model was developed for the removal of bound solvent that incorporates models for heat transfer and desolvation kinetics. The proposed heat transfer model differs from previously reported models in two respects: it accounts for the effects of a gas gap between the vessel wall and solids on the overall heat transfer coefficient, and headspace pressure on the mean free path length of the inert gas and thereby on the heat transfer between the vessel wall and the first layer of solids. A computational methodology was developed incorporating the effects of mixing and headspace pressure to simulate the drying profile using a modified model framework within the Dynochem software. A dryer operational protocol was designed based on the desolvation kinetics, thermal stability studies of wet and dry cake, and the understanding gained through model simulations, resulting in a multifold reduction in drying time.

  15. System-Cost-Optimized Smart EVSE for Residential Application: Final Technical Report including Manufacturing Plan

    SciTech Connect

    Zhu, Charles

    2015-05-15

    In the 2nd quarter of 2012, a program was formally initiated at Delta Products to develop smart-grid-enabled Electric Vehicle Supply Equipment (EVSE) product for residential use. The project was funded in part by the U.S. Department of Energy (DOE), under award DE-OE0000590. Delta products was the prime contractor to DOE during the three year duration of the project. In addition to Delta Products, several additional supplier-partners were engaged in this research and development (R&D) program, including Detroit Edison DTE, Mercedes Benz Research and Development North America, and kVA. This report summarizes the program and describes the key research outcomes of the program. A technical history of the project activities is provided, which describes the key steps taken in the research and the findings made at successive stages in the multi-stage work. The evolution of an EVSE prototype system is described in detail, culminating in prototypes shipped to Department of Energy Laboratories for final qualification. After the program history is reviewed, the key attributes of the resulting EVSE are described in terms of functionality, performance, and cost. The results clearly demonstrate the ability of this EVSE to meet or exceed DOE's targets for this program, including: construction of a working product-intent prototype of a smart-grid-enabled EVSE, with suitable connectivity to grid management and home-energy management systems, revenue-grade metering, and related technical functions; and cost reduction of 50% or more compared to typical market priced EVSEs at the time of DOE's funding opportunity announcement (FOA), which was released in mid 2011. In addition to meeting all the program goals, the program was completed within the original budget and timeline established at the time of the award. The summary program budget and timeline, comparing plan versus actual values, is provided for reference, along with several supporting explanatory notes. Technical information

  16. Analysis of metal salts by combining spectral windows: Quantifying and optimizing cost-effectiveness of multispectral analyses

    SciTech Connect

    Wu, J.L.; Egan, W.J.; Myrick, M.L.; Milanovich, F.P.

    1999-04-01

    Luminescence and Raman measurements of metal (Er{sup 3+}, Tb{sup 3+}, Sm{sup 3+}, Eu{sup 3+}, UO{sub 2}{sup 2+}, and Na{sup +}) nitrates from multiple spectral windows are combined and analyzed to determine whether this multispectral approach provides any benefit over the best single-measurement, single-window technique by itself. The individual measurements we combined were obtained under the following conditions (1) excited at 488 nm and detected from 500 to 730 nm, (2) excited at 514.5 nm and detected from 530 to 700 nm, and (3) excited at 785 nm and detected from 800 nm to 920 nm. The first two conditions were excellent for producing fluorescence, while the latter was best for Raman spectroscopy because it avoided most fluorescence. Single-window measurements, particularly the near-infrared Raman spectroscopy of the nitrate counterions, were sufficiently similar to make visual identification of the metal salts from the spectra impossible. The combined data set provided easy visual differentiation between the metal salts. However, we found that hierarchical cluster analysis of the single-window measurements could also be used to identify the metal nitrates even when only the Raman spectral windows of the nitrates were studied. To select windows for a multispectral approach rationally, we define an efficacy parameter, {Pi}{sub T}, for each possible combination of measurement windows, plus a formula for cost estimation for the multispectral system. This parameter is evaluated for the data presented in the paper, with the conclusion that the least costly acceptable combination consists of only two windows with the same excitation source. In cases such as these, pooled multispectral analysis is proposed as an excellent means of selecting the appropriate technique and wavelength range for an optimal single measurement set, but subsets of the pooled data may function equally well or even better for specific monitoring tasks, especially when cost analysis is necessary

  17. Optimizing Mouse Surgery with Online Rectal Temperature Monitoring and Preoperative Heat Supply. Effects on Post-Ischemic Acute Kidney Injury.

    PubMed

    Marschner, Julian A; Schäfer, Hannah; Holderied, Alexander; Anders, Hans-Joachim

    2016-01-01

    Body temperature affects outcomes of tissue injury. We hypothesized that online body core temperature recording and selective interventions help to standardize peri-interventional temperature control and the reliability of outcomes in experimental renal ischemia reperfusion injury (IRI). We recorded core temperature in up to seven mice in parallel using a Thermes USB recorder and ret-3-iso rectal probes with three different protocols. Setup A: Heating pad during ischemia time; Setup B: Heating pad from incision to wound closure; Setup C: A ventilated heating chamber before surgery and during ischemia time with surgeries performed on a heating pad. Temperature profile recording displayed significant declines upon installing anesthesia. The profile of the baseline experimental setup A revealed that <1% of the temperature readings were within the target range of 36.5 to 38.5°C. Setup B and C increased the target range readings to 34.6 ± 28.0% and 99.3 ± 1.5%, respectively. Setup C significantly increased S3 tubular necrosis, neutrophil influx, and mRNA expression of kidney injury markers. In addition, using setup C different ischemia times generated a linear correlation with acute tubular necrosis parameters at a low variability, which further correlated with the degree of kidney atrophy 5 weeks after surgery. Changing temperature control setup A to C was equivalent to 10 minutes more ischemia time. We conclude that body temperature drops quickly in mice upon initiating anesthesia. Immediate heat supply, e.g. in a ventilated heating chamber, and online core temperature monitoring can help to standardize and optimize experimental outcomes.

  18. Optimization-Based Management of Energy Systems

    DTIC Science & Technology

    2011-05-11

    initial cost with renewable usage constraints NC CO OK NY TX Grid Yes, unlimited Yes, unlimited Yes, unlimited Yes, unlimited Yes, unlimited Solar PV (KW...35 MW 0 0 0 20 MW Wind turbines(kW) 65 MW 70 MW 65 MW 55 MW 50 MW CHP (microturbines+absChiller) 5 MW microturbines 17.5 MW microturbines 35 MW...optimized 0 0.5 1 1.5 2 2.5 3 3.5 4 x 10 6 Total Cost Grid Energy Cost Grid Demand Cost Heating Cost CHP Natural Gas Cost Diesel Cost Annual Cost

  19. The Planetary Observer Program. [planning by NASA and scientific community including cost optimization overview

    NASA Technical Reports Server (NTRS)

    Blume, W. H.

    1984-01-01

    An overview is presented of NASA's plans for the Planetary Observer Program, whose key element is to control the cost of each mission while establishing a long-term, stable base for the planetary sciences. The SSEC (Solar System Exploration Committee) has endorsed the view that many high science priority inner solar system missions are possible through the use of spacecraft derived from existing earth-orbital spacecraft. It has also recommended the application of space hardware such as that used on the Voyager and Galileo missions, development of both a new modular spacecraft for outer planet, comet, and main-belt asteroid missions (Mariner Mark II Program), and a multi-mission operations system to support future missions after the Venus Radar Mapper (VRM), and Galileo. A set of missions for the SSEC's Core Program has been recommended; they include: the VRM, the Mars Geoscience/Climatology Observer, the Comet Rendezvous/Asteroid Flyby, the Lunar Geoscience Orbiter, the Near-Earth Asteroid Rendezvous, the Venus Atmosphere Probe, the Mars Aeronomy Orbiter, the Mars Surface Probe, and the Comet Intercept Sample Return.

  20. Optimization of inulinase production by a newly isolated Aspergillus tubingensis CR16 using low cost substrates.

    PubMed

    Trivedi, Sneha; Divecha, Jyoti; Shah, Amita

    2012-09-01

    Production of an extracellular, thermostable inulinase was carried out by a newly isolated strain of Aspergillus tubingensis CR16 using wheat bran and corn steep liquor (CSL) under solid state fermentation (SSF). Response surface methodology (RSM) involving Box Behnken design (BBD) was employed for the optimization of process parameters viz. time period of fermentation, % moisture content, inoculum size and pH of the medium. Maximum yield of inulinase was 257±11.4 U/g, obtained by inoculating 5 g of wheat bran with 10(9) spores/ml, at initial 71.2% moisture content and pH 6.1 after 103 h of fermentation along with 1358.6±0.8 U/g of invertase activity. Crude inulinase showed maximum activity at 60 °C and pH 5.0. The enzyme was found to be thermostable retaining about 90% of its activity for 4.5 h at 60 °C. Fructose was produced as an end product of inulin hydrolysis proving that the enzyme produced was exoinulinase.

  1. Recent improvements in optimizing use of dispersants as a cost-effective oil spill countermeasure technique

    SciTech Connect

    Daling, P.S.; Indrebo, G.

    1996-12-31

    Several oil spill incidents during recent years have demonstrated that the physico-chemical properties of spilled oil and the effectiveness of available combat methods are, in addition to the prevailing environmental and weather conditions, key factors that determine the consequences of an oil spill. Pre-spill analyses of the feasibility and effectiveness of different response strategies, such as mechanical recovery and dispersants, for actual oils under various environmental conditions should therefore be an essential part of any oil spill contingency planning to optimize the overall {open_quotes}Net Environmental Benefit{close_quotes} of a combat operation. During the four-year research program ESCOST ({open_quotes}ESSO-SINTEF Coastal Oil Spill Treatment Program{close_quotes}), significant improvements have been made in oil spill combat methods and in tools for use in contingency planning and decision-making during oil spill operations. This paper will present an overview of the main findings obtained with respect to oil weathering and oil spill dispersant treatment.

  2. Development & Optimization of Materials and Processes for a Cost Effective Photoelectrochemical Hydrogen Production System. Final report

    SciTech Connect

    McFarland, Eric W

    2011-01-17

    The overall project objective was to apply high throughput experimentation and combinatorial methods together with novel syntheses to discover and optimize efficient, practical, and economically sustainable materials for photoelectrochemical production of bulk hydrogen from water. Automated electrochemical synthesis and photoelectrochemical screening systems were designed and constructed and used to study a variety of new photoelectrocatalytic materials. We evaluated photocatalytic performance in the dark and under illumination with or without applied bias in a high-throughput manner and did detailed evaluation on many materials. Significant attention was given to -Fe2O3 based semiconductor materials and thin films with different dopants were synthesized by co-electrodeposition techniques. Approximately 30 dopants including Al, Zn, Cu, Ni, Co, Cr, Mo, Ti, Pt, etc. were investigated. Hematite thin films doped with Al, Ti, Pt, Cr, and Mo exhibited significant improvements in efficiency for photoelectrochemical water splitting compared with undoped hematite. In several cases we collaborated with theorists who used density functional theory to help explain performance trends and suggest new materials. The best materials were investigated in detail by X-ray diffraction (XRD), scanning electron microscopy (SEM), ultraviolet-visual spectroscopy (UV-Vis), X-ray photoelectron spectroscopy (XPS). The photoelectrocatalytic performance of the thin films was evaluated and their incident photon

  3. Optimization of Fin Distribution to Improve the Temperature Uniformity of a Heat Exchanger in a Thermoelectric Generator

    NASA Astrophysics Data System (ADS)

    Wang, Yiping; Wu, Cheng; Tang, Zebo; Yang, Xue; Deng, Yadong; Su, Chuqi

    2015-06-01

    Thermoelectric generators (TEGs) are currently a topic of interest for energy recovery in vehicles. By applying TEGs to the outside surface of the exhaust tailpipe, a small amount of electrical power can be generated because of the temperature difference between the hot exhaust gases and the automobile coolant. The amount of power is anticipated to be a few hundred watts based on the expected temperature difference and the properties of the thermoelectric materials used in TEGs. It is well know that, for thermoelectric exhaust energy recovery, the temperature uniformity of the heat exchangers has a strong influence on the electric power generation. In the current research, the temperature uniformity of a heat exchanger was improved by optimizing the fin distribution to maximize the electric power generated for a given vehicle TEG. A computational fluid dynamics (CFD) model of the heat exchanger was constructed to assess the influence of different fin distributions on the temperature uniformity and the pressure drop in the exhaust system. For the fin distributions, four factors were considered: the length of, spacing between, angle of, and thickness of the fins. Based on these four factors, a design of experiments study using the orthogonal experimental method was conducted to analyze the sensitivity to the design variables and build a database to set up a surrogate model using the Kriging response surface method. A multi-island genetic algorithm was used to optimize the fin distribution based on this surrogate model. To validate the accuracy of the CFD model, a generic heat exchanger module was manufactured and a related testbed constructed, then the temperature distribution on the surface of the exchanger was measured to compare with the results obtained by CFD.

  4. Modeling optimal process conditions for UV-heat inactivation of foodborne pathogens in liquid foods.

    PubMed

    Gayán, Elisa; Serrano, María Jesús; Álvarez, Ignacio; Condón, Santiago

    2016-12-01

    The combination of ultraviolet radiation and heat (UV-H treatment) has been demonstrated as a promising strategy to overcome the limited UV germicidal effect in fruit juices. Nonetheless, there are so far no data regarding the efficacy of the combined process for the inactivation of bacterial foodborne pathogens in other liquid foods with different pH and composition. In this investigation, the optimum UV-H processing conditions for the inactivation of Escherichia coli, Salmonella Typhimurium, Listeria monocytogenes, and S. aureus in chicken and vegetable broth, in addition to juices, were determined. From these data models that accurately predict the most advantageous UV-H treatment temperature and the expected synergistic lethal effect from UV and heat resistance data separately were constructed. Equations demonstrated that the optimum UV-H treatment temperature mostly depended on heat resistance, whereas the maximum synergistic lethal effect also was affected by the UV resistance of the microorganism of concern in a particular food.

  5. Optimal Mandates and The Welfare Cost of Asymmetric Information: Evidence from The U.K. Annuity Market*

    PubMed Central

    Einav, Liran; Finkelstein, Amy; Schrimpf, Paul

    2009-01-01

    Much of the extensive empirical literature on insurance markets has focused on whether adverse selection can be detected. Once detected, however, there has been little attempt to quantify its welfare cost, or to assess whether and what potential government interventions may reduce these costs. To do so, we develop a model of annuity contract choice and estimate it using data from the U.K. annuity market. The model allows for private information about mortality risk as well as heterogeneity in preferences over different contract options. We focus on the choice of length of guarantee among individuals who are required to buy annuities. The results suggest that asymmetric information along the guarantee margin reduces welfare relative to a first best symmetric information benchmark by about £127 million per year, or about 2 percent of annuitized wealth. We also find that by requiring that individuals choose the longest guarantee period allowed, mandates could achieve the first-best allocation. However, we estimate that other mandated guarantee lengths would have detrimental effects on welfare. Since determining the optimal mandate is empirically difficult, our findings suggest that achieving welfare gains through mandatory social insurance may be harder in practice than simple theory may suggest. PMID:20592943

  6. Capacity optimization of battery-generator hybrid power system: Toward minimizing maintenance cost in expeditionary basecamp/operational energy applications

    NASA Astrophysics Data System (ADS)

    Onwuanumkpe, Jude C.

    Low and transient load condition are known to have deleterious impact on the efficiency and health of diesel generators (DGs). Extensive operation under such loads reduces fuel consumption and energy conversion efficiency, and contribute to diesel engine degradation, damage, or catastrophic failure. Non-ideal loads are prevalent in expeditionary base camps that support contingency operations in austere environments or remote locations where grid electricity is either non-existent or inaccessible. The impact of such loads on DGs exacerbates already overburdened basecamp energy logistics requirements. There is a need, therefore, to eliminate or prevent the occurrence of non-ideal loads. Although advances in diesel engine technologies have improved their performance, DGs remain vulnerable to the consequences of non-ideal loads and inherent inefficiencies of combustion. The mechanisms through which DGs respond to and mitigate non-ideal loads are also mechanically stressful and energy-intensive. Thus, this research investigated the idea of using batteries to prevent DGs from encountering non-ideal loads, as a way to reduce basecamp energy logistics requirements. Using a simple semi-empirical approach, the study modeled and simulated a battery-DG hybrid system under various load conditions. The simulation allowed for synthesis of design space in which specified battery and generator capacity can achieve optimal savings in fuel consumption and maintenance cost. Results show that a right-sized battery-diesel generator system allows for more than 50% cost savings relative to a standalone generator.

  7. Evaluation of interpolation effects on upsampling and accuracy of cost functions-based optimized automatic image registration.

    PubMed

    Mahmoudzadeh, Amir Pasha; Kashou, Nasser H

    2013-01-01

    Interpolation has become a default operation in image processing and medical imaging and is one of the important factors in the success of an intensity-based registration method. Interpolation is needed if the fractional unit of motion is not matched and located on the high resolution (HR) grid. The purpose of this work is to present a systematic evaluation of eight standard interpolation techniques (trilinear, nearest neighbor, cubic Lagrangian, quintic Lagrangian, hepatic Lagrangian, windowed Sinc, B-spline 3rd order, and B-spline 4th order) and to compare the effect of cost functions (least squares (LS), normalized mutual information (NMI), normalized cross correlation (NCC), and correlation ratio (CR)) for optimized automatic image registration (OAIR) on 3D spoiled gradient recalled (SPGR) magnetic resonance images (MRI) of the brain acquired using a 3T GE MR scanner. Subsampling was performed in the axial, sagittal, and coronal directions to emulate three low resolution datasets. Afterwards, the low resolution datasets were upsampled using different interpolation methods, and they were then compared to the high resolution data. The mean squared error, peak signal to noise, joint entropy, and cost functions were computed for quantitative assessment of the method. Magnetic resonance image scans and joint histogram were used for qualitative assessment of the method.

  8. Low-cost multi-vehicle air temperature measurements for heat load assessment in local-scale climate applications

    NASA Astrophysics Data System (ADS)

    Zuvela-Aloise, Maja; Weyss, Gernot; Aloise, Giulliano; Mifka, Boris; Löffelmann, Philemon; Hollosi, Brigitta; Nemec, Johana; Vucetic, Visnja

    2014-05-01

    In the recent years there has been a strong interest in exploring the potential of low-cost measurement devices as alternative source of meteorological monitoring data, especially in the urban areas where high-density observations become crucial for appropriate heat load assessment. One of the simple, but efficient approaches for gathering large amount of spatial data is through mobile measurement campaigns in which the sensors are attached to driving vehicles. However, non-standardized data collecting procedure, instrument quality, their response-time and design, variable device ventilation and radiation protection influence the reliability of the gathered data. We investigate what accuracy can be expected from the data collected through low-cost mobile measurements and whether the achieved quality of the data is sufficient for validation of the state-of-the-art local-scale climate models. We tested 5 types of temperature sensors and data loggers: Maxim iButton, Lascar EL-USB-2-LCD+ and Onset HOBO UX100-003 as market available devices and self-designed solar powered Arduino-based data loggers combined with the AOSONG AM2315 and Sensirion SHT21 temperature and humidity sensors. The devices were calibrated and tested in stationary mode at the Austrian Weather Service showing accuracy between 0.1°C and 0.8°C, which was mostly within the device specification range. In mobile mode, the best response-time was found for self-designed device with Arduino-based data logger and Sensirion SHT21 sensor. However, the device lacks the mechanical robustness and should be further improved for broad-range applications. We organized 4 measurement tours: two taking place in urban environment (Vienna, Austria in July 2011 and July 2013) and two in countryside with complex terrain of Mid-Adriatic islands (Hvar and Korcula, Croatia in August 2013). Measurements were taken on clear-sky, dry and hot days. We combined multiple devices attached to bicycle and cars with different

  9. Computational Fluid Dynamic Solutions of Optimized Heat Shields Designed for Earth Entry

    DTIC Science & Technology

    2010-01-01

    College Park Trajectory Optimization Program(UPTOP),23 which employs a 4th-order Runge - Kutta rou- tine to propagate the three-degrees-of-freedom point...support of whom is greatly appreciated. Special thanks must go to my coworkers in the hypersonics group (Neal Smith, Vijay Ramasubramanian, Adam Beerman...12 1.2.3.2 Radiation . . . . . . . . . . . . . . . . . . . . . . . . 13 1.2.4 Optimization Methods

  10. Comparing Maintenance Costs of Geothermal Heat Pump Systems with other HVAC Systems in Lincoln Public Schools: Repair, Service, and Corrective Actions

    SciTech Connect

    Martin, M.A.; Durfee, D.J.; Hughes, P.J.

    1999-06-19

    The Lincoln Public School District, in Lincoln, Nebraska, recently installed vertical-bore geothermal heat pump systems in four, new, elementary schools. Because the district has consistent maintenance records and procedures, it was possible to study repair, service and corrective maintenance requests for 20 schools in the district. Each school studied provides cooling to over 70% of its total floor area and uses one of the following heating and cooling systems: vertical-bore geothermal heat pumps (GHPs), air-cooled chiller with gas-fired hot water boiler (ACUGHWB), water-cooled chiller with gas-fired hot water boiler (WCCYGHWB), or water-cooled chiller with gas-fired steam boiler (WCUGSB). Preventative maintenance and capital renewal activities were not included in the available database. GHP schools reported average total costs at 2.13 cents/ft{sup 2}-yr, followed by ACC/GHWB schools at 2.88 cents/ft{sup 2}-yr, WCC/GSB schools at 3.73 cents/ft{sup 2}-yr, and WCC/GHWB schools at 6.07 cents/ft{sup 2}-yr. Because of tax-exemptions on material purchases, a reliance on in-house labor, and the absence of preventative maintenance records in the database, these costs are lower than those reported in previous studies. A strong relationship (R{sup 2}=O.52) was found between costs examined and cooling system age: the newer the cooling equipment, the less it costs to maintain.

  11. Increasing costs due to ocean acidification drives phytoplankton to be more heavily calcified: optimal growth strategy of coccolithophores.

    PubMed

    Irie, Takahiro; Bessho, Kazuhiro; Findlay, Helen S; Calosi, Piero

    2010-10-15

    Ocean acidification is potentially one of the greatest threats to marine ecosystems and global carbon cycling. Amongst calcifying organisms, coccolithophores have received special attention because their calcite precipitation plays a significant role in alkalinity flux to the deep ocean (i.e., inorganic carbon pump). Currently, empirical effort is devoted to evaluating the plastic responses to acidification, but evolutionary considerations are missing from this approach. We thus constructed an optimality model to evaluate the evolutionary response of coccolithophorid life history, assuming that their exoskeleton (coccolith) serves to reduce the instantaneous mortality rates. Our model predicted that natural selection favors constructing more heavily calcified exoskeleton in response to increased acidification-driven costs. This counter-intuitive response occurs because the fitness benefit of choosing a better-defended, slower growth strategy in more acidic conditions, outweighs that of accelerating the cell cycle, as this occurs by producing less calcified exoskeleton. Contrary to the widely held belief, the evolutionarily optimized population can precipitate larger amounts of CaCO(3) during the bloom in more acidified seawater, depending on parameter values. These findings suggest that ocean acidification may enhance the calcification rates of marine organisms as an adaptive response, possibly accompanied by higher carbon fixation ability. Our theory also provides a compelling explanation for the multispecific fossil time-series record from ∼200 years ago to present, in which mean coccolith size has increased along with rising atmospheric CO(2) concentration.

  12. Low-cost conversion of polycrystalline silicon into sheet by HEM and FAST. [Heat Exchanger Method and Fixed Abrasive Slicing Technique

    NASA Technical Reports Server (NTRS)

    Khattak, C. P.; Schmid, F.

    1980-01-01

    The conversion of polycrystalline silicon to sheet form (the wafers produced are 10 cm x 10 cm cross section with minimum surface damage) by the Heat Exchanger Method (HEM) and multi-wire Fixed Abrasive Slicing Technique (FAST), as a means of reducing the cost of solar arrays for adaptation of photovoltaic technology for terrestrial applications, is given. A schematic of a HEM furnace, which includes a silica crucible, and developments in the HEM process are presented. A new machine for slicing with wire was designed and fabricated. The high-speed slicer has been used to slice 19 wafers per cm from 10 cm diameter crystals. Both HEM and FAST are low-cost processes and they have the potential of giving one of the lowest add-on costs ($6.24 and $6.48 per square meter of sheet respectively, with the combination add-on cost of $14.87 per square meter) of this conversion.

  13. Balancing incident heat and ion flow for process optimization in plasma based ion implantation

    NASA Astrophysics Data System (ADS)

    Mändl, S.; Manova, D.; Rauschenbach, B.

    2002-06-01

    Plasma based ion implantation at elevated temperatures is a technology often used to obtain thick surface layers of several µm by thermally activated diffusion, e.g. nitrogen in steel, titanium or aluminium. By lowering the pulse voltage at constant temperature, the current density can be increased at a constant heat flow. However, an upper limit is given by the ratio of the diffusion rate transporting the implanted ions from the surface towards the bulk and the sputter yield. This sputtering of the surface dominates for very high current densities and limits the maximum achievable layer thickness. Different maximum current densities were found for the four investigated systems - nitrogen in different steel grades, aluminium and titanium, as well as oxygen in titanium - reflecting the varying diffusivities. Additional requirements, besides the maximum current density, as a conformal treatment for complex objects containing small holes or trenches, as well as short heating times, can be solved most effectively by pulsed voltages in the range of 2-5 kV and an additional heating of the sample. The problem of a sample cooling time of several hours after the treatment is recognized. A partial solution would be to increase the gas pressure during the cooling phase for a more effective heat dissipation.

  14. Statistical optimization of microchannel heat sink (MCHS) geometry cooled by different nanofluids using RSM analysis

    NASA Astrophysics Data System (ADS)

    Rahimi-Gorji, M.; Pourmehran, O.; Hatami, M.; Ganji, D. D.

    2015-02-01

    In this work, an analytical investigation of the heat transfer for the microchannel heat sink (MCHS) cooled by different nanofluids (Cu, Al2O3, Ag, TiO2 in water and ethylene glycol as base fluids) is studied by the porous media approach and the Galerkin method and results are compared with numerical procedure. Response surface methodology (RSM) is applied to obtain the desirability of the optimum design of the channel geometry. The effective thermal conductivity and viscosity of the nanofluid are calculated by the Patel et al. and Khanafer et al. model, respectively, and MCHS is considered as a porous medium, as proposed by Kim and Kim. In addition, to deal with nanofluid heat transfer, a model based on the Brownian motion of nanoparticles is used. The effects of the nanoparticles volume fraction, nanoparticle type and size, base fluid type, etc., on the temperature distribution, velocity and Nusselt number are considered. Results show that, by increasing the nanoparticles volume fraction, the Brownian movement of the particles, which carries the heat and distributes it to the surroundings, increases and, consequently, the difference between coolant and wall temperature becomes less.

  15. A Total Cost of Ownership Model for Low Temperature PEM Fuel Cells in Combined Heat and Power and Backup Power Applications

    SciTech Connect

    University of California, Berkeley; Wei, Max; Lipman, Timothy; Mayyas, Ahmad; Chien, Joshua; Chan, Shuk Han; Gosselin, David; Breunig, Hanna; Stadler, Michael; McKone, Thomas; Beattie, Paul; Chong, Patricia; Colella, Whitney; James, Brian

    2014-06-23

    A total cost of ownership model is described for low temperature proton exchange membrane stationary fuel cell systems for combined heat and power (CHP) applications from 1-250kW and backup power applications from 1-50kW. System designs and functional specifications for these two applications were developed across the range of system power levels. Bottom-up cost estimates were made for balance of plant costs, and detailed direct cost estimates for key fuel cell stack components were derived using design-for-manufacturing-and-assembly techniques. The development of high throughput, automated processes achieving high yield are projected to reduce the cost for fuel cell stacks to the $300/kW level at an annual production volume of 100 MW. Several promising combinations of building types and geographical location in the U.S. were identified for installation of fuel cell CHP systems based on the LBNL modelling tool DER CAM. Life-cycle modelling and externality assessment were done for hotels and hospitals. Reduced electricity demand charges, heating credits and carbon credits can reduce the effective cost of electricity ($/kWhe) by 26-44percent in locations such as Minneapolis, where high carbon intensity electricity from the grid is displaces by a fuel cell system operating on reformate fuel. This project extends the scope of existing cost studies to include externalities and ancillary financial benefits and thus provides a more comprehensive picture of fuel cell system benefits, consistent with a policy and incentive environment that increasingly values these ancillary benefits. The project provides a critical, new modelling capacity and should aid a broad range of policy makers in assessing the integrated costs and benefits of fuel cell systems versus other distributed generation technologies.

  16. Electricity and combined heat and power from municipal solid waste; theoretically optimal investment decision time and emissions trading implications.

    PubMed

    Tolis, Athanasios; Rentizelas, Athanasios; Aravossis, Konstantin; Tatsiopoulos, Ilias

    2010-11-01

    Waste management has become a great social concern for modern societies. Landfill emissions have been identified among the major contributors of global warming and climate changes with significant impact in national economies. The energy industry constitutes an additional greenhouse gas emitter, while at the same time it is characterized by significant costs and uncertain fuel prices. The above implications have triggered different policies and measures worldwide to address the management of municipal solid wastes on the one hand and the impacts from energy production on the other. Emerging methods of energy recovery from waste may address both concerns simultaneously. In this work a comparative study of co-generation investments based on municipal solid waste is presented, focusing on the evolution of their economical performance over time. A real-options algorithm has been adopted investigating different options of energy recovery from waste: incineration, gasification and landfill biogas exploitation. The financial contributors are identified and the impact of greenhouse gas trading is analysed in terms of financial yields, considering landfilling as the baseline scenario. The results indicate an advantage of combined heat and power over solely electricity production. Gasification, has failed in some European installations. Incineration on the other hand, proves to be more attractive than the competing alternatives, mainly due to its higher power production efficiency, lower investment costs and lower emission rates. Although these characteristics may not drastically change over time, either immediate or irreversible investment decisions might be reconsidered under the current selling prices of heat, power and CO(2) allowances.

  17. Optimization of reproductive management programs using lift chart analysis and cost-sensitive evaluation of classification errors.

    PubMed

    Shahinfar, Saleh; Guenther, Jerry N; Page, C David; Kalantari, Afshin S; Cabrera, Victor E; Fricke, Paul M; Weigel, Kent A

    2015-06-01

    The common practice on most commercial dairy farms is to inseminate all cows that are eligible for breeding, while ignoring (or absorbing) the costs associated with semen and labor directed toward low-fertility cows that are unlikely to conceive. Modern analytical methods, such as machine learning algorithms, can be applied to cow-specific explanatory variables for the purpose of computing probabilities of success or failure associated with upcoming insemination events. Lift chart analysis can identify subsets of high fertility cows that are likely to conceive and are therefore appropriate targets for insemination (e.g., with conventional artificial insemination semen or expensive sex-enhanced semen), as well as subsets of low-fertility cows that are unlikely to conceive and should therefore be passed over at that point in time. Although such a strategy might be economically viable, the management, environmental, and financial conditions on one farm might differ widely from conditions on the next, and hence the reproductive management recommendations derived from such a tool may be suboptimal for specific farms. When coupled with cost-sensitive evaluation of misclassified and correctly classified insemination events, the strategy can be a potentially powerful tool for optimizing the reproductive management of individual farms. In the present study, lift chart analysis and cost-sensitive evaluation were applied to a data set consisting of 54,806 insemination events of primiparous Holstein cows on 26 Wisconsin farms, as well as a data set with 17,197 insemination events of primiparous Holstein cows on 3 Wisconsin farms, where the latter had more detailed information regarding health events of individual cows. In the first data set, the gains in profit associated with limiting inseminations to subsets of 79 to 97% of the most fertile eligible cows ranged from $0.44 to $2.18 per eligible cow in a monthly breeding period, depending on days in milk at breeding and milk

  18. Optimization of an ammonia-cooled rectangular microchannel heat sink using multi-objective non-dominated sorting genetic algorithm (NSGA2)

    NASA Astrophysics Data System (ADS)

    Adham, Ahmed Mohammed; Mohd-Ghazali, Normah; Ahmad, Robiah

    2012-10-01

    The ever decreasing size of modern electronic packaging has induced researchers to search for an effective and efficient heat removal system to handle the continuously increasing power density. Investigations have involved different geometry, material and coolant to address the thermal management issues. This paper reports the potential improvement in the overall performance of a rectangular microchannel heat sink using a new gaseous coolant namely ammonia gas. Using a multi-objective general optimization scheme with the thermal resistance model as an analysis method in combination with a non-dominated sorting genetic algorithm as an optimization technique, it was found that significant reduction in the total thermal resistance up to 34 % for ammonia-cooled compared to air-cooled microchannel heat sink under the same operating conditions is achievable. In addition, a considerable decrease in the microchannel heat sink's mass up to 30 % was achieved due to the different heat sink's material used.

  19. Optimization by means of an analytical heat transfer model of a thermal insulation for CSP applications based on radiative shields

    NASA Astrophysics Data System (ADS)

    Gaetano, A.; Roncolato, J.; Montorfano, D.; Barbato, M. C.; Ambrosetti, G.; Pedretti, A.

    2016-05-01

    The employment of new gaseous heat transfer fluids as air or CO2, which are cheaper and environmentally friendly, is drawing more and more attention within the field of Concentrated Solar Power applications. However, despite the advantages, their use requires receivers with a larger heat transfer area and flow cross section with a consequent greater volume of thermal insulation. Solid thermal insulations currently used present high thermal inertia which is energetically penalizing during the daily transient phases faced by the main plant components (e.g. receivers). With the aim of overcoming this drawback a thermal insulation based on radiative shields is presented in this study. Starting from an initial layout comprising a solid thermal insulation layer, the geometry was optimized avoiding the use of the solid insulation keeping performance and fulfilling the geometrical constraints. An analytical Matlab model was implemented to assess the system thermal behavior in terms of heat loss taking into account conductive, convective and radiative contributions. Accurate 2D Computational Fluid Dynamics (CFD) simulations were run to validate the Matlab model which was then used to select the most promising among three new different designs.

  20. A New Approach in Optimizing the Induction Heating Process Using Flux Concentrators: Application to 4340 Steel Spur Gear

    NASA Astrophysics Data System (ADS)

    Barka, Noureddine; Chebak, Ahmed; El Ouafi, Abderrazak; Jahazi, Mohammad; Menou, Abdellah

    2014-09-01

    The beneficial effects of using flux concentrators during induction heat treatment process of spur gears made of 4340 high strength steel is demonstrated using 3D finite element model. The model is developed by coupling electromagnetic field and heat transfer equations and simulated by using Comsol software. Based on an adequate formulation and taking into account material properties and process parameters, the model allows calculating temperature distribution in the gear tooth. A new approach is proposed to reduce the electromagnetic edge effect in the gear teeth which allows achieving optimum hardness profile after induction heat treatment. In the proposed method, the principal gear is positioned in sandwich between two other gears having the same geometry that act as flux concentrators. The gap between the gear and the flux concentrators was optimized by studying temperature variation between the tip and root regions of gear teeth. Using the proposed model, it was possible identifying processing conditions that allow for quasi-uniform final temperature profile in the medium and high frequency conditions during induction hardening of spur gears.