Study of advanced radial outflow turbine for solar steam Rankine engines

NASA Technical Reports Server (NTRS)

Martin, C.; Kolenc, T.

1979-01-01

The performance characteristics of various steam Rankine engine configurations for solar electric power generation were investigated. A radial outflow steam turbine was investigated to determine: (1) a method for predicting performance from experimental data; (2) the flexibility of a single design with regard to power output and pressure ratio; and (3) the effect of varying the number of turbine stages. All turbine designs were restricted to be compatible with commercially available gearboxes and generators. A study of several operating methods and control schemes for the steam Rankine engine shows that from an efficiency and control simplicity standpoint, the best approach is to hold turbine inlet temperature constant, vary turbine inlet pressure to match load, and allow condenser temperature to float maintaining constant heat rejection load.

Utilization of recently developed codes for high power Brayton and Rankine cycle power systems

NASA Technical Reports Server (NTRS)

Doherty, Michael P.

1993-01-01

Two recently developed FORTRAN computer codes for high power Brayton and Rankine thermodynamic cycle analysis for space power applications are presented. The codes were written in support of an effort to develop a series of subsystem models for multimegawatt Nuclear Electric Propulsion, but their use is not limited just to nuclear heat sources or to electric propulsion. Code development background, a description of the codes, some sample input/output from one of the codes, and state future plans/implications for the use of these codes by NASA's Lewis Research Center are provided.

Application of Biomass from Palm Oil Mill for Organic Rankine Cycle to Generate Power in North Sumatera Indonesia

NASA Astrophysics Data System (ADS)

Nur, T. B.; Pane, Z.; Amin, M. N.

2017-03-01

Due to increasing oil and gas demand with the depletion of fossil resources in the current situation make efficient energy systems and alternative energy conversion processes are urgently needed. With the great potential of resources in Indonesia, make biomass has been considered as one of major potential fuel and renewable resource for the near future. In this paper, the potential of palm oil mill waste as a bioenergy source has been investigated. An organic Rankine cycle (ORC) small scale power plant has been preliminary designed to generate electricity. The working fluid candidates for the ORC plant based on the heat source temperature domains have been investigated. The ORC system with a regenerator has higher thermal efficiency than the basic ORC system. The study demonstrates the technical feasibility of ORC solutions in terms of resources optimizations and reducing of greenhouse gas emissions.

Development of a solar receiver for an organic rankine cycle engine

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

Haskins, H.J.; Taylor, R.M.; Osborn, D.B.

A solar receiver is described for use with an organic Rankine cycle (ORC) engine as part of the Small Community Solar Thermal Power Experiment (SCSE). The selected receiver concept is a direct-heated, once-through, monotube boiler normally operating at supercritical pressure. Fabrication methods for the receiver core have been developed and validated with flat braze samples, cylindrical segment samples, and a complete full-scale core assembly.

Performance analysis of low temperature heat source of organic Rankine cycle for geothermal application

NASA Astrophysics Data System (ADS)

Pintoro, A.; Ambarita, H.; Nur, T. B.; Napitupulu, F. H.

2018-02-01

Indonesia has a high potential energy resources from geothermal activities. Base on the report of Asian Development Bank and World Bank, the estimated of Indonesian hydrothermal geothermal resource considered to be the largest among the world. If it’s can be utilized to produce the electric power, it’s can contribute to increasing the electrification rates in Indonesia. In this study, an experimental studied of electric power generation, utilizing the Organic Rankine Cycle (ORC) system to convert the low level heat of hydrothermal as an energy source. The temperature of hydrothermal was modelled as hot water from water boiler which has a temperature range from 60 °C - 100 °C to heat up the organic working fluid of ORC system. The system can generated 1,337.7 watts of electricity when operated using R134A with hot water inlet temperature of 100 °C. Changing system working fluid to R245fa, the net power obtained increase to 1,908.9 watts with the same heat source condition. This study showed that the ORC system can be implemented to utilize low temperature heat source of hydrothermal in Indonesia.

Cascaded organic rankine cycles for waste heat utilization

DOEpatents

Radcliff, Thomas D [Vernon, CT; Biederman, Bruce P [West Hartford, CT; Brasz, Joost J [Fayetteville, NY

2011-05-17

A pair of organic Rankine cycle systems (20, 25) are combined and their respective organic working fluids are chosen such that the organic working fluid of the first organic Rankine cycle is condensed at a condensation temperature that is well above the boiling point of the organic working fluid of the second organic Rankine style system, and a single common heat exchanger (23) is used for both the condenser of the first organic Rankine cycle system and the evaporator of the second organic Rankine cycle system. A preferred organic working fluid of the first system is toluene and that of the second organic working fluid is R245fa.

A new multi-domain method based on an analytical control surface for linear and second-order mean drift wave loads on floating bodies

NASA Astrophysics Data System (ADS)

Liang, Hui; Chen, Xiaobo

2017-10-01

A novel multi-domain method based on an analytical control surface is proposed by combining the use of free-surface Green function and Rankine source function. A cylindrical control surface is introduced to subdivide the fluid domain into external and internal domains. Unlike the traditional domain decomposition strategy or multi-block method, the control surface here is not panelized, on which the velocity potential and normal velocity components are analytically expressed as a series of base functions composed of Laguerre function in vertical coordinate and Fourier series in the circumference. Free-surface Green function is applied in the external domain, and the boundary integral equation is constructed on the control surface in the sense of Galerkin collocation via integrating test functions orthogonal to base functions over the control surface. The external solution gives rise to the so-called Dirichlet-to-Neumann [DN2] and Neumann-to-Dirichlet [ND2] relations on the control surface. Irregular frequencies, which are only dependent on the radius of the control surface, are present in the external solution, and they are removed by extending the boundary integral equation to the interior free surface (circular disc) on which the null normal derivative of potential is imposed, and the dipole distribution is expressed as Fourier-Bessel expansion on the disc. In the internal domain, where the Rankine source function is adopted, new boundary integral equations are formulated. The point collocation is imposed over the body surface and free surface, while the collocation of the Galerkin type is applied on the control surface. The present method is valid in the computation of both linear and second-order mean drift wave loads. Furthermore, the second-order mean drift force based on the middle-field formulation can be calculated analytically by using the coefficients of the Fourier-Laguerre expansion.

A novel high-temperature ejector-topping power cycle

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

Freedman, B.Z.; Lior, N.

1994-01-01

A novel, patented topping power cycle is described that takes its energy from a very high-temperature heat source and in which the temperature of the heat sink is still high enough to operate another, conventional power cycle. The top temperatures heat source is used to evaporate a low saturation pressure liquid, which serves as the driving fluid for compressing the secondary fluid in an ejector. Due to the inherently simple construction of ejectors, they are well suited for operation at temperatures higher than those that can be used with gas turbines. The gases exiting from the ejector transfer heat tomore » the lower temperature cycle, and are separated by condensing the primary fluid. The secondary gas is then used to drive a turbine. For a system using sodium as the primary fluid and helium as the secondary fluid, and using a bottoming Rankine steam cycle, the overall thermal efficiency can be at least 11 percent better than that of conventional steam Rankine cycles.« less

Rankine cycle system and method

DOEpatents

Ernst, Timothy C.; Nelson, Christopher R.

2014-09-09

A Rankine cycle waste heat recovery system uses a receiver with a maximum liquid working fluid level lower than the minimum liquid working fluid level of a sub-cooler of the waste heat recovery system. The receiver may have a position that is physically lower than the sub-cooler's position. A valve controls transfer of fluid between several of the components in the waste heat recovery system, especially from the receiver to the sub-cooler. The system may also have an associated control module.

Evaluation of solid oxide fuel cell systems for electricity generation

NASA Technical Reports Server (NTRS)

Somers, E. V.; Vidt, E. J.; Grimble, R. E.

1982-01-01

Air blown (low BTU) gasification with atmospheric pressure Solid Electrolyte Fuel Cells (SOFC) and Rankine bottoming cycle, oxygen blown (medium BTU) gasification with atmospheric pressure SOFC and Rankine bottoming cycle, air blown gasification with pressurized SOFC and combined Brayton/Rankine bottoming cycle, oxygen blown gasification with pressurized SOFC and combined Brayton/Rankine bottoming cycle were evaluated.

Heat pump system

DOEpatents

Swenson, Paul F.; Moore, Paul B.

1979-01-01

An air heating and cooling system for a building includes an expansion-type refrigeration circuit and a heat engine. The refrigeration circuit includes two heat exchangers, one of which is communicated with a source of indoor air from the building and the other of which is communicated with a source of air from outside the building. The heat engine includes a heat rejection circuit having a source of rejected heat and a primary heat exchanger connected to the source of rejected heat. The heat rejection circuit also includes an evaporator in heat exchange relation with the primary heat exchanger, a heat engine indoor heat exchanger, and a heat engine outdoor heat exchanger. The indoor heat exchangers are disposed in series air flow relationship, with the heat engine indoor heat exchanger being disposed downstream from the refrigeration circuit indoor heat exchanger. The outdoor heat exchangers are also disposed in series air flow relationship, with the heat engine outdoor heat exchanger disposed downstream from the refrigeration circuit outdoor heat exchanger. A common fluid is used in both of the indoor heat exchangers and in both of the outdoor heat exchangers. In a first embodiment, the heat engine is a Rankine cycle engine. In a second embodiment, the heat engine is a non-Rankine cycle engine.

Heat pump system

DOEpatents

Swenson, Paul F.; Moore, Paul B.

1982-01-01

An air heating and cooling system for a building includes an expansion-type refrigeration circuit and a heat engine. The refrigeration circuit includes two heat exchangers, one of which is communicated with a source of indoor air from the building and the other of which is communicated with a source of air from outside the building. The heat engine includes a heat rejection circuit having a source of rejected heat and a primary heat exchanger connected to the source of rejected heat. The heat rejection circuit also includes an evaporator in heat exchange relation with the primary heat exchanger, a heat engine indoor heat exchanger, and a heat engine outdoor heat exchanger. The indoor heat exchangers are disposed in series air flow relationship, with the heat engine indoor heat exchanger being disposed downstream from the refrigeration circuit indoor heat exchanger. The outdoor heat exchangers are also disposed in series air flow relationship, with the heat engine outdoor heat exchanger disposed downstream from the refrigeration circuit outdoor heat exchanger. A common fluid is used in both of the indoor heat exchanges and in both of the outdoor heat exchangers. In a first embodiment, the heat engine is a Rankine cycle engine. In a second embodiment, the heat engine is a non-Rankine cycle engine.

Combined rankine and vapor compression cycles

DOEpatents

Radcliff, Thomas D.; Biederman, Bruce P.; Brasz, Joost J.

2005-04-19

An organic rankine cycle system is combined with a vapor compression cycle system with the turbine generator of the organic rankine cycle generating the power necessary to operate the motor of the refrigerant compressor. The vapor compression cycle is applied with its evaporator cooling the inlet air into a gas turbine, and the organic rankine cycle is applied to receive heat from a gas turbine exhaust to heat its boiler within one embodiment, a common condenser is used for the organic rankine cycle and the vapor compression cycle, with a common refrigerant, R-245a being circulated within both systems. In another embodiment, the turbine driven generator has a common shaft connected to the compressor to thereby eliminate the need for a separate motor to drive the compressor. In another embodiment, an organic rankine cycle system is applied to an internal combustion engine to cool the fluids thereof, and the turbo charged air is cooled first by the organic rankine cycle system and then by an air conditioner prior to passing into the intake of the engine.

Concentrating Solar Power Projects - Olivenza 1 | Concentrating Solar Power

Science.gov Websites

Manufacturer: Siemens Turbine Description: 5 extractions Output Type: Steam Rankine Power Cycle Pressure: 100.0 bar Cooling Method: Wet cooling Cooling Method Description: Cooling Towers

Research on theoretical optimization and experimental verification of minimum resistance hull form based on Rankine source method

NASA Astrophysics Data System (ADS)

Zhang, Bao-Ji; Zhang, Zhu-Xin

2015-09-01

To obtain low resistance and high efficiency energy-saving ship, minimum total resistance hull form design method is studied based on potential flow theory of wave-making resistance and considering the effects of tail viscous separation. With the sum of wave resistance and viscous resistance as objective functions and the parameters of B-Spline function as design variables, mathematical models are built using Nonlinear Programming Method (NLP) ensuring the basic limit of displacement and considering rear viscous separation. We develop ship lines optimization procedures with intellectual property rights. Series60 is used as parent ship in optimization design to obtain improved ship (Series60-1) theoretically. Then drag tests for the improved ship (Series60-1) is made to get the actual minimum total resistance hull form.

Concentrating Solar Power Projects - Enerstar | Concentrating Solar Power |

Science.gov Websites

Capacity (Net): 50.0 MW Turbine Manufacturer: Man-Turbo Turbine Description: 3 extractions Output Type : Steam Rankine Power Cycle Pressure: 100.0 bar Cooling Method: Wet cooling Cooling Method Description

Applications guide for waste heat recovery

NASA Technical Reports Server (NTRS)

Moynihan, P. I.

1983-01-01

The state-of-the-art of commercially available organic Rankine cycle (ORC) hardware from a literature search and industry survey is assessed. Engineering criteria for applying ORC technology are established, and a set of nomograms to enable the rapid sizing of the equipment is presented. A comparison of an ORC system with conventional heat recovery techniques can be made with a nomogram developed for a recuperative heat exchanger. A graphical technique for evaluating the economic aspects of an ORC system and conventional heat recovery method is discussed: also included is a description of anticipated future trends in organic Rankine cycle R&D.

Integrated biomass pyrolysis with organic Rankine cycle for power generation

NASA Astrophysics Data System (ADS)

Nur, T. B.; Syahputra, A. W.

2018-02-01

The growing interest on Organic Rankine Cycle (ORC) application to produce electricity by utilizing biomass energy sources are increasingly due to its successfully used to generate power from waste heat available in industrial processes. Biomass pyrolysis is one of the thermochemical technologies for converting biomass into energy and chemical products consisting of liquid bio-oil, solid biochar, and pyrolytic gas. In the application, biomass pyrolysis can be divided into three main categories; slow, fast and flash pyrolysis mainly aiming at maximizing the products of bio-oil or biochar. The temperature of synthesis gas generated during processes can be used for Organic Rankine Cycle to generate power. The heat from synthesis gas during pyrolysis processes was transfer by thermal oil heater to evaporate ORC working fluid in the evaporator unit. In this study, the potential of the palm oil empty fruit bunch, palm oil shell, and tree bark have been used as fuel from biomass to generate electricity by integrated with ORC. The Syltherm-XLT thermal oil was used as the heat carrier from combustion burner, while R245fa was used as the working fluid for ORC system. Through Aspen Plus, this study analyses the influences on performance of main thermodynamic parameters, showing the possibilities of reaching an optimum performance for different working conditions that are characteristics of different design parameters.

ANL/RBC: A computer code for the analysis of Rankine bottoming cycles, including system cost evaluation and off-design performance

NASA Technical Reports Server (NTRS)

Mclennan, G. A.

1986-01-01

This report describes, and is a User's Manual for, a computer code (ANL/RBC) which calculates cycle performance for Rankine bottoming cycles extracting heat from a specified source gas stream. The code calculates cycle power and efficiency and the sizes for the heat exchangers, using tabular input of the properties of the cycle working fluid. An option is provided to calculate the costs of system components from user defined input cost functions. These cost functions may be defined in equation form or by numerical tabular data. A variety of functional forms have been included for these functions and they may be combined to create very general cost functions. An optional calculation mode can be used to determine the off-design performance of a system when operated away from the design-point, using the heat exchanger areas calculated for the design-point.

Development of a solar-powered residential air conditioner: System optimization preliminary specification

NASA Technical Reports Server (NTRS)

Rousseau, J.; Hwang, K. C.

1975-01-01

Investigations aimed at the optimization of a baseline Rankine cycle solar powered air conditioner and the development of a preliminary system specification were conducted. Efforts encompassed the following: (1) investigations of the use of recuperators/regenerators to enhance the performance of the baseline system, (2) development of an off-design computer program for system performance prediction, (3) optimization of the turbocompressor design to cover a broad range of conditions and permit operation at low heat source water temperatures, (4) generation of parametric data describing system performance (COP and capacity), (5) development and evaluation of candidate system augmentation concepts and selection of the optimum approach, (6) generation of auxiliary power requirement data, (7) development of a complete solar collector-thermal storage-air conditioner computer program, (8) evaluation of the baseline Rankine air conditioner over a five day period simulating the NASA solar house operation, and (9) evaluation of the air conditioner as a heat pump.

Advantage of incorporating geothermal energy into power-station cycles

NASA Astrophysics Data System (ADS)

White, A. A. L.

1980-06-01

The generation of electricity from low-temperature geothermal sources has been hampered by the low conversion efficiencies of Rankine cycle operating below 150 C. It is shown how the electrical output derived from a geothermal borehole may be substantially improved on that expected from these cycles by incorporating the geothermal heat into a conventional steam-cycle power station to provide feedwater heating. This technique can yield thermal conversion efficiencies of 11% which, for a well-head temperature of 100 C, is 50% greater than the output expected from a Rankine cycle. Coupled with the smaller capital costs involved, feedwater heating is thus a more attractive technique of converting heat into electricity. Although power stations above suitable geothermal resources would ideally have the geothermal heat incorporated from the design stage, experiments at Marchwood Power Station have shown that small existing sets can be modified to accept geothermal feedwater heating.

Design and process integration of organic Rankine cycle utilizing biomass for power generation

NASA Astrophysics Data System (ADS)

Ependi, S.; Nur, T. B.

2018-02-01

Indonesia has high potential biomass energy sources from palm oil mill industry activities. The growing interest on Organic Rankine Cycle (ORC) application to produce electricity by utilizing biomass energy sources are increasingly due to its successfully used for generating electricity from rejected waste heat to the environment in industrial processes. In this study, the potential of the palm oil empty fruit bunch, and wood chip have been used as fuel for biomass to generate electricity based ORC with combustion processes. The heat from combustion burner was transfer by thermal oil heater to evaporate ORC working fluid in the evaporator unit. The Syltherm-XLT thermal oil was used as the heat carrier from combustion burner, while R245fa was used as the working fluid for ORC unit. Appropriate designs integration from biomass combustion unit to ORC unit have been analyzed and proposed to generate expander shaft-work. Moreover, the effect of recuperator on the total system efficiency has also been investigated. It was observed that the fuel consumption was increased when the ORC unit equipped recuperator operated until certain pressure and decreased when operated at high pressure.

Working fluid selection for the Organic Rankine Cycle (ORC) exhaust heat recovery of an internal combustion engine power plant

NASA Astrophysics Data System (ADS)

Douvartzides, S.; Karmalis, I.

2016-11-01

Organic Rankine cycle technology is capable to efficiently convert low-grade heat into useful mechanical power. In the present investigation such a cycle is used for the recovery of heat from the exhaust gases of a four stroke V18 MAN 51/60DF internal combustion engine power plant operating with natural gas. Design is focused on the selection of the appropriate working fluid of the Rankine cycle in terms of thermodynamic, environmental and safety criteria. 37 candidate fluids have been considered and all Rankine cycles examined were subcritical. The thermodynamic analysis of all fluids has been comparatively undertaken and the effect of key operation conditions such as the evaporation pressure and the superheating temperature was taken into account. By appropriately selecting the working fluid and the Rankine cycle operation conditions the overall plant efficiency was improved by 5.52% and fuel consumption was reduced by 12.69%.

Time-domain hybrid method for simulating large amplitude motions of ships advancing in waves

NASA Astrophysics Data System (ADS)

Liu, Shukui; Papanikolaou, Apostolos D.

2011-03-01

Typical results obtained by a newly developed, nonlinear time domain hybrid method for simulating large amplitude motions of ships advancing with constant forward speed in waves are presented. The method is hybrid in the way of combining a time-domain transient Green function method and a Rankine source method. The present approach employs a simple double integration algorithm with respect to time to simulate the free-surface boundary condition. During the simulation, the diffraction and radiation forces are computed by pressure integration over the mean wetted surface, whereas the incident wave and hydrostatic restoring forces/moments are calculated on the instantaneously wetted surface of the hull. Typical numerical results of application of the method to the seakeeping performance of a standard containership, namely the ITTC S175, are herein presented. Comparisons have been made between the results from the present method, the frequency domain 3D panel method (NEWDRIFT) of NTUA-SDL and available experimental data and good agreement has been observed for all studied cases between the results of the present method and comparable other data.

Domain decomposition and matching for time-domain analysis of motions of ships advancing in head sea

NASA Astrophysics Data System (ADS)

Tang, Kai; Zhu, Ren-chuan; Miao, Guo-ping; Fan, Ju

2014-08-01

A domain decomposition and matching method in the time-domain is outlined for simulating the motions of ships advancing in waves. The flow field is decomposed into inner and outer domains by an imaginary control surface, and the Rankine source method is applied to the inner domain while the transient Green function method is used in the outer domain. Two initial boundary value problems are matched on the control surface. The corresponding numerical codes are developed, and the added masses, wave exciting forces and ship motions advancing in head sea for Series 60 ship and S175 containership, are presented and verified. A good agreement has been obtained when the numerical results are compared with the experimental data and other references. It shows that the present method is more efficient because of the panel discretization only in the inner domain during the numerical calculation, and good numerical stability is proved to avoid divergence problem regarding ships with flare.

A Feasibility Study of CO2-Based Rankine Cycle Powered by Solar Energy

NASA Astrophysics Data System (ADS)

Zhang, Xin-Rong; Yamaguchi, Hiroshi; Fujima, Katsumi; Enomoto, Masatoshi; Sawada, Noboru

An experiment study was carried out in order to investigate feasibility of CO2-based Rankine cycle powered by solar energy. The proposed cycle is to achieve a cogeneration of heat and power, which consists of evacuated solar tube collectors, power generating turbine, heat recovery system, and feed pump. The Rankine cycle of the system utilizes solar collectors to convert CO2 into high-temperature supercritical state, used to drive a turbine and produce electrical power. The cycle also recovers thermal energy, which can be used for absorption refrigerator, air conditioning, hot water supply so on for a building. A set of experimental set-up was constructed to investigate the performance of the CO2-based Rankine cycle. The results show the cycle can achieve production of heat and power with reasonable thermodynamics efficiency and has a great potential of the application of the CO2-based Rankine cycle powered by solar energy. In addition, some research interests related to the present study will also be discussed in this paper.

Innovative Aircraft Design Study. Task II. Nuclear Aircraft Concepts

DTIC Science & Technology

1977-04-01

simple cycle and system with no feedwater heating, reheating, or moisture removal from the turbine. The steam Rankine cycle is schematically shown in... cycle . With the SO Rankine cycle , the fluid is heated supercritically without a phase change, thereby reducing the complexity of the heater as...one and ten percent lighter in ramp weight than the other candidates at both payloads. Analyses of several Rankine and Brayton nuclear propulsion cycles

Comparative thermodynamic performance of some Rankine/Brayton cycle configurations for a low-temperature energy application

NASA Technical Reports Server (NTRS)

Lansing, F. L.

1977-01-01

Various configurations combining solar-Rankine and fuel-Brayton cycles were analyzed in order to find the arrangement which has the highest thermal efficiency and the smallest fuel share. A numerical example is given to evaluate both the thermodynamic performance and the economic feasibility of each configuration. The solar-assisted regenerative Rankine cycle was found to be leading the candidates from both points of energy utilization and fuel conservation.

Organic Rankine Kilowatt Isotope Power System. Final phase I report

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

Not Available

1978-07-15

On 1 August 1975 under Department of Energy Contract EN-77-C-02-4299, Sundstrand Energy Systems commenced development of a Kilowatt Isotope Power System (KIPS) directed toward satisfying the higher power requirements of satellites of the 1980s and beyond. The KIPS is a /sup 238/PuO/sub 2/ fueled organic Rankine cycle turbine power system which will provide design output power in the range of 500 to 2000 W/sub (e)/ with a minimum of system changes. The principal objectives of the Phase 1 development effort were to: conceptually design a flight system; design a Ground Demonstration System (GDS) that is prototypic of the flight systemmore » in order to prove the feasibility of the flight system design; fabricate and assemble the GDS; and performance and endurance test the GDS using electric heaters in lieu of the isotope heat source. Results of the work performed under the Phase 1 contract to 1 July 1978 are presented.« less

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

Owens, J.J.; Nejedlik, J.F.; Vogt, J.W.

The SNAP II system consists of a reactor heat source, a mercury Rankine engine, and an alternator. The problems involved in selecting materials for the SNAP II mercury system were studied. A discussion is given of the corrosion mechanisms involved in a system in which mercury is the working fluid. The problem resolves itself into selecting materials with the best combination of engineering properties for the application and highest resistance to mercury corrosion at the anticipated temperature. (auth)

Evaluation of Working Fluids for Organic Rankine Cycle Based on Exergy Analysis

NASA Astrophysics Data System (ADS)

Setiawan, D.; Subrata, I. D. M.; Purwanto, Y. A.; Tambunan, A. H.

2018-05-01

One of the crucial aspects to determine the performance of Organic Rankine Cycle (ORC) is the selection of appropriate working fluids. This paper describes the simulative performance of several organic fluid and water as working fluid of an ORC based on exergy analysis with a heat source from waste heat recovery. The simulation was conducted by using Engineering Equation Solver (EES). The effect of several parameters and thermodynamic properties of working fluid was analyzed, and part of them was used as variables for the simulation in order to determine their sensitivity to the exergy efficiency changes. The results of this study showed that water is not appropriate to be used as working fluid at temperature lower than 130 °C, because the expansion process falls in saturated area. It was also found that Benzene had the highest exergy efficiency, i.e. about 10.49%, among the dry type working fluid. The increasing turbine inlet temperature did not lead to the increase of exergy efficiency when using organic working fluids with critical temperature near heat source temperature. Meanwhile, exergy efficiency decreasing linearly with the increasing condenser inlet temperature. In addition, it was found that working fluid with high latent heat of vaporization and specific heat exert in high exergy efficiency.

Advanced binary geothermal power plants: Limits of performance

NASA Astrophysics Data System (ADS)

Bliem, C. J.; Mines, G. L.

1991-01-01

The Heat Cycle Research Program is investigating potential improvements to power cycles utilizing moderate temperature geothermal resources to produce electrical power. Investigations have specifically examined Rankine cycle binary power systems. Binary Rankine cycles are more efficient than the flash steam cycles at moderate resource temperature, achieving a higher net brine effectiveness. At resource conditions similar to those at the Heber binary plant, it has been shown that mixtures of saturated hydrocarbons (alkanes) or halogenated hydrocarbons operating in a supercritical Rankine cycle gave improved performance over Rankine cycles with the pure working fluids executing single or dual boiling cycles or supercritical cycles. Recently, other types of cycles have been proposed for binary geothermal service. The feasible limits on efficiency of a plant given practical limits on equipment performance is explored and the methods used in these advanced concept plants to achieve the maximum possible efficiency are discussed. (Here feasible is intended to mean reasonably achievable and not cost effective.) No direct economic analysis was made because of the sensitivity of economic results to site specific input. The limit of performance of three advanced plants were considered. The performance predictions were taken from the developers of each concept. The advanced plants considered appear to be approaching the feasible limit of performance. Ultimately, the plant designer must weigh the advantages and disadvantages of the the different cycles to find the best plant for a given service. In addition, a standard is presented of comparison of the work which has been done in the Heat Cycle Research Program and in the industrial sector by Exergy, Inc. and Polythermal Technologies.

Optimum working fluids for solar powered Rankine cycle cooling of buildings

NASA Astrophysics Data System (ADS)

Wali, E.

1980-01-01

A number of fluids were screened for their operational reliability and thermal stability as working fluids for domestic solar Rankine cycle cooling. The results indicate that the halogenated compound R-113, followed by the fluorinated compound FC-88, is best suited for safe Rankine cycle operation. Further dynamic investigations are, however, needed to study the thermal stability of these fluids in the presence and absence of lubricants in copper, steel, and alloy conduits

Method of operating a thermal engine powered by a chemical reaction

DOEpatents

Ross, John; Escher, Claus

1988-01-01

The invention involves a novel method of increasing the efficiency of a thermal engine. Heat is generated by a non-linear chemical reaction of reactants, said heat being transferred to a thermal engine such as Rankine cycle power plant. The novel method includes externally perturbing one or more of the thermodynamic variables of said non-linear chemical reaction.

Method of operating a thermal engine powered by a chemical reaction

DOEpatents

Ross, J.; Escher, C.

1988-06-07

The invention involves a novel method of increasing the efficiency of a thermal engine. Heat is generated by a non-linear chemical reaction of reactants, said heat being transferred to a thermal engine such as Rankine cycle power plant. The novel method includes externally perturbing one or more of the thermodynamic variables of said non-linear chemical reaction. 7 figs.

A Study of Waste-Heat-Boiler Size and Performance of a Conceptual Marine COGAS System.

DTIC Science & Technology

1980-02-01

The addition of a waste-heat boiler which extracts heat from the gas turbine exhaust gas to operate a bottoming Rankine cycle is one way to improve the...do not change significantly. Higher saturation pressure actually results in a somewhat lower boiler heat transfer, but the Rankine - cycle performance...of heat transferred in the waste-heat boiler and (2) the conversion efficiency of the Rankine cycle . In sizing the waste-heat boiler, attention was

The dish-Rankine SCSTPE program (Engineering Experiment no. 1). [systems engineering and economic analysis for a small community solar thermal electric system

NASA Technical Reports Server (NTRS)

Pons, R. L.; Grigsby, C. E.

1980-01-01

Activities planned for phase 2 Of the Small Community Solar Thermal Power Experiment (PFDR) program are summarized with emphasis on a dish-Rankine point focusing distributed receiver solar thermal electric system. Major design efforts include: (1) development of an advanced concept indirect-heated receiver;(2) development of hardware and software for a totally unmanned power plant control system; (3) implementation of a hybrid digital simulator which will validate plant operation prior to field testing; and (4) the acquisition of an efficient organic Rankine cycle power conversion unit. Preliminary performance analyses indicate that a mass-produced dish-Rankine PFDR system is potentially capable of producing electricity at a levelized busbar energy cost of 60 to 70 mills per KWh and with a capital cost of about $1300 per KW.

A collaborative sequential meta-analysis of individual patient data from randomized trials of endovascular therapy and tPA vs. tPA alone for acute ischemic stroke: ThRombEctomy And tPA (TREAT) analysis: statistical analysis plan for a sequential meta-analysis performed within the VISTA-Endovascular collaboration.

PubMed

MacIsaac, Rachael L; Khatri, Pooja; Bendszus, Martin; Bracard, Serge; Broderick, Joseph; Campbell, Bruce; Ciccone, Alfonso; Dávalos, Antoni; Davis, Stephen M; Demchuk, Andrew; Diener, Hans-Christoph; Dippel, Diederik; Donnan, Geoffrey A; Fiehler, Jens; Fiorella, David; Goyal, Mayank; Hacke, Werner; Hill, Michael D; Jahan, Reza; Jauch, Edward; Jovin, Tudor; Kidwell, Chelsea S; Liebeskind, David; Majoie, Charles B; Martins, Sheila Cristina Ouriques; Mitchell, Peter; Mocco, J; Muir, Keith W; Nogueira, Raul; Saver, Jeffrey L; Schonewille, Wouter J; Siddiqui, Adnan H; Thomalla, Götz; Tomsick, Thomas A; Turk, Aquilla S; White, Philip; Zaidat, Osama; Lees, Kennedy R

2015-10-01

Endovascular treatment has been shown to restore blood flow effectively. Second-generation medical devices such as stent retrievers are now showing overwhelming efficacy in clinical trials, particularly in conjunction with intravenous recombinant tissue plasminogen activator. This statistical analysis plan utilizing a novel, sequential approach describes a prospective, individual patient data analysis of endovascular therapy in conjunction with intravenous recombinant tissue plasminogen activator agreed upon by the Thrombectomy and Tissue Plasminogen Activator Collaborative Group. This protocol will specify the primary outcome for efficacy, as 'favorable' outcome defined by the ordinal distribution of the modified Rankin Scale measured at three-months poststroke, but with modified Rankin Scales 5 and 6 collapsed into a single category. The primary analysis will aim to answer the questions: 'what is the treatment effect of endovascular therapy with intravenous recombinant tissue plasminogen activator compared to intravenous tissue plasminogen activator alone on full scale modified Rankin Scale at 3 months?' and 'to what extent do key patient characteristics influence the treatment effect of endovascular therapy?'. Key secondary outcomes include effect of endovascular therapy on death within 90 days; analyses of modified Rankin Scale using dichotomized methods; and effects of endovascular therapy on symptomatic intracranial hemorrhage. Several secondary analyses will be considered as well as expanding patient cohorts to intravenous recombinant tissue plasminogen activator-ineligible patients, should data allow. This collaborative meta-analysis of individual participant data from randomized trials of endovascular therapy vs. control in conjunction with intravenous thrombolysis will demonstrate the efficacy and generalizability of endovascular therapy with intravenous thrombolysis as a concomitant medication. © 2015 World Stroke Organization.

Apolipoprotein E modifies neurological outcome by affecting cerebral edema but not hematoma size after intracerebral hemorrhage in humans

PubMed Central

James, Michael L.; Blessing, Robert; Bennett, Ellen; Laskowitz, Daniel T.

2009-01-01

Introduction To address the mechanisms by which apoE polymorphism affects functional outcome after intracerebral hemorrhage in humans, we tested the hypothesis that the presence of the APOE4 allele results in amplified inflammatory responses and increased cerebral edema. Methods We prospectively enrolled and collected data on 21 adult patients consecutively admitted to Duke University Hospital with supratentorial intracerebral hematoma including hemorrhage volume, midline shift, modified Rankin Score, Glasgow Outcome Score, and APOE genotype. Hemorrhage size (cm3) and midline shift (mm), at the level of the thalamus, were measured by computed tomography within 36 hours of admission. Rankin and Glasgow Scores were determined at discharge. Student’s t-test was used to analyze hemorrhage size, midline shift, and Glasgow Outcome Score and logistical regression was used to measure allele affect on modified Rankin Score. When analyzing modified Rankin Score, patients were grouped by favorable outcome (0–2) or unfavorable (3–6). Results Out of 21 patients, 11 possessed at least one APOE4 allele (APOE4+). There was no difference in hemorrhage volume (25.8 v. 38.3 mm for APOE4− v. APOE4+, respectively) between the groups, but there was a significant difference in midline shift (p=0.04, 0.7 v. 4mm). Functional outcomes were worse for the patients possessing at least one APOE4 allele (p=0.04) Conclusion The presence of APOE4 is associated with poor functional outcomes in humans after intracerebral hemorrhage. Our data suggest that the mechanism for this may be increased cerebral edema and not larger hematoma volume. PMID:19251191

The study on working fluids of airborne power generation system based on Rankine cycle by heat energy

NASA Astrophysics Data System (ADS)

Guo, Yuan

2017-05-01

This paper proposed a new concept named airborne power generation system based on Rankine cycle by heat energy, namely, the presented system combined the Rankine cycle with environmental control system in aircraft to recycle the waste heat of engine bleed air with high temperature and generate power. This paper mainly discussed the choosing of optimum working fluid which could apply in the combined power generation system mentioned above when the temperature of the coming bleed air was about 400 degree centigrade.

Assessment of alternative power sources for mobile mining machinery

NASA Technical Reports Server (NTRS)

Cairelli, J. E.; Tomazic, W. A.; Evans, D. G.; Klann, J. L.

1981-01-01

Alternative mobile power sources for mining applications were assessed. A wide variety of heat engines and energy systems was examined as potential alternatives to presently used power systems. The present mobile power systems are electrical trailing cable, electrical battery, and diesel - with diesel being largely limited in the United States to noncoal mines. Each candidate power source was evaluated for the following requirements: (1) ability to achieve the duty cycle; (2) ability to meet Government regulations; (3) availability (production readiness); (4) market availability; and (5) packaging capability. Screening reduced the list of candidates to the following power sources: diesel, stirling, gas turbine, rankine (steam), advanced electric (batteries), mechanical energy storage (flywheel), and use of hydrogen evolved from metal hydrides. This list of candidates is divided into two classes of alternative power sources for mining applications, heat engines and energy storage systems.

Assessment of alternative power sources for mobile mining machinery

NASA Astrophysics Data System (ADS)

Cairelli, J. E.; Tomazic, W. A.; Evans, D. G.; Klann, J. L.

1981-12-01

Alternative mobile power sources for mining applications were assessed. A wide variety of heat engines and energy systems was examined as potential alternatives to presently used power systems. The present mobile power systems are electrical trailing cable, electrical battery, and diesel - with diesel being largely limited in the United States to noncoal mines. Each candidate power source was evaluated for the following requirements: (1) ability to achieve the duty cycle; (2) ability to meet Government regulations; (3) availability (production readiness); (4) market availability; and (5) packaging capability. Screening reduced the list of candidates to the following power sources: diesel, stirling, gas turbine, rankine (steam), advanced electric (batteries), mechanical energy storage (flywheel), and use of hydrogen evolved from metal hydrides. This list of candidates is divided into two classes of alternative power sources for mining applications, heat engines and energy storage systems.

Emissions-critical charge cooling using an organic rankine cycle

DOEpatents

Ernst, Timothy C.; Nelson, Christopher R.

2014-07-15

The disclosure provides a system including a Rankine power cycle cooling subsystem providing emissions-critical charge cooling of an input charge flow. The system includes a boiler fluidly coupled to the input charge flow, an energy conversion device fluidly coupled to the boiler, a condenser fluidly coupled to the energy conversion device, a pump fluidly coupled to the condenser and the boiler, an adjuster that adjusts at least one parameter of the Rankine power cycle subsystem to change a temperature of the input charge exiting the boiler, and a sensor adapted to sense a temperature characteristic of the vaporized input charge. The system includes a controller that can determine a target temperature of the input charge sufficient to meet or exceed predetermined target emissions and cause the adjuster to adjust at least one parameter of the Rankine power cycle to achieve the predetermined target emissions.

Scalable Electrospray Components for Portable Power Applications Using MEMS Fabrication Techniques

DTIC Science & Technology

2006-11-01

electric field induced between the electrode and the conducting liquid initially causes a Taylor cone to form at the tip of the tube where the field...voltage source, creating a strong electrical potential difference between the two. A Taylor -cone forms at the tip of each nozzle from the electro...Combustion Institute, 20, pp. 965-972. Muler, N. and Fréchette, L.G., 2002: Performance Analysis of Brayton and Rankine Cycle Microsystems for

Thermal power systems, point-focusing distributed receiver technology project. Volume 2: Detailed report

NASA Technical Reports Server (NTRS)

Lucas, J.

1979-01-01

Thermal or electrical power from the sun's radiated energy through Point-Focusing Distributed Receiver technology is the goal of this Project. The energy thus produced must be economically competitive with other sources. The Project supports the industrial development of technology and hardware for extracting energy from solar power to achieve the stated goal. Present studies are working to concentrate the solar energy through mirrors or lenses, to a working fluid or gas, and through a power converter change to an energy source useful to man. Rankine-cycle and Brayton-cycle engines are currently being developed as the most promising energy converters for our near future needs.

ANALYTICAL PROCEDURES FOR CHARACTERIZING UNREGULATED EMISSIONS FROM VEHICLES USING MIDDLE-DISTILLATE FUELS

EPA Science Inventory

This research program was initiated with the objective of developing, codifying and testing a group of chemical analytical methods for measuring toxic compounds in the exhaust of distillate-fueled engines (i.e. diesel, gas turbine, Stirling, or Rankin cycle powerplants). It is a ...

Rankine cycle condenser pressure control using an energy conversion device bypass valve

DOEpatents

Ernst, Timothy C; Nelson, Christopher R; Zigan, James A

2014-04-01

The disclosure provides a waste heat recovery system and method in which pressure in a Rankine cycle (RC) system of the WHR system is regulated by diverting working fluid from entering an inlet of an energy conversion device of the RC system. In the system, an inlet of a controllable bypass valve is fluidly coupled to a working fluid path upstream of an energy conversion device of the RC system, and an outlet of the bypass valve is fluidly coupled to the working fluid path upstream of the condenser of the RC system such that working fluid passing through the bypass valve bypasses the energy conversion device and increases the pressure in a condenser. A controller determines the temperature and pressure of the working fluid and controls the bypass valve to regulate pressure in the condenser.

Next-Generation Bioacoustic Analysis Software

DTIC Science & Technology

2015-09-30

estimated to miss 38% of sperm whales that are on a ship’s trackline ( Barlow and Rankin 2004), and more at greater distances from the trackline. Other...scanning (J. Barlow , pers. comm). Acoustic methods, in contrast to visual ones, function well in darkness, fog, high sea states, and other inclement

Megawatt Class Nuclear Space Power Systems (MCNSPS) conceptual design and evaluation report. Volume 3, technologies 2: Power conversion

NASA Technical Reports Server (NTRS)

Wetch, J. R.

1988-01-01

The major power conversion concepts considered for the Megawatt Class Nuclear Space Power System (MCNSPS) are discussed. These concepts include: (1) Rankine alkali-metal-vapor turbine alternators; (2) in-core thermionic conversion; (3) Brayton gas turbine alternators; and (4) free piston Stirling engine linear alternators. Considerations important to the coupling of these four conversion alternatives to an appropriate nuclear reactor heat source are examined along with the comparative performance characteristics of the combined systems meeting MCNSPS requirements.

Thermodynamic Analysis of a Rankine Cycle Powered Vapor Compression Ice Maker Using Solar Energy

PubMed Central

Hu, Bing; Bu, Xianbiao; Ma, Weibin

2014-01-01

To develop the organic Rankine-vapor compression ice maker driven by solar energy, a thermodynamic model was developed and the effects of generation temperature, condensation temperature, and working fluid types on the system performance were analyzed. The results show that the cooling power per square meter collector and ice production per square meter collector per day depend largely on generation temperature and condensation temperature and they increase firstly and then decrease with increasing generation temperature. For every working fluid there is an optimal generation temperature at which organic Rankine efficiency achieves the maximum value. The cooling power per square meter collector and ice production per square meter collector per day are, respectively, 126.44 W m−2 and 7.61 kg m−2 day−1 at the generation temperature of 140°C for working fluid of R245fa, which demonstrates the feasibility of organic Rankine cycle powered vapor compression ice maker. PMID:25202735

Refrigeration oils for low GWP refrigerants in various applications

NASA Astrophysics Data System (ADS)

Saito, R.; Sundaresan, S. G.

2017-08-01

The practical use of the refrigeration systems is considered as a methods to suppress global warming. The replacement of a refrigerant with a new one that has lower global warming potential (GWP) has been underway for several years. For the application fields of refrigerators, domestic air conditioners, automotive air conditioners and hot water dispensers, the investigation has almost finished. It is still underway for the application fields of commercial air conditioners and chillers, refrigeration facilities for cold storage, etc. And now, the refrigeration system is being applied in various ways to decrease global warming above the generation of electric power with organic Rankine cycle, the binary electric generation with ground source heat pump, and so on. In these situations, various refrigerants are developed and several kinds of suitable refrigeration oils are selected. This paper presents the consideration of suitable refrigeration oil for the various low GWP refrigerants.

Organic rankine cycle system for use with a reciprocating engine

DOEpatents

Radcliff, Thomas D.; McCormick, Duane; Brasz, Joost J.

2006-01-17

In a waste heat recovery system wherein an organic rankine cycle system uses waste heat from the fluids of a reciprocating engine, provision is made to continue operation of the engine even during periods when the organic rankine cycle system is inoperative, by providing an auxiliary pump and a bypass for the refrigerant flow around the turbine. Provision is also made to divert the engine exhaust gases from the evaporator during such periods of operation. In one embodiment, the auxiliary pump is made to operate simultaneously with the primary pump during normal operations, thereby allowing the primary pump to operate at lower speeds with less likelihood of cavitation.

Moderate temperature control technology for a lunar base

NASA Technical Reports Server (NTRS)

Swanson, Theodore D.; Sridhar, K. R.; Gottmann, Matthias

1993-01-01

A parametric analysis is performed to compare different heat pump based thermal control systems for a Lunar Base. Rankine cycle and absorption cycle heat pumps are compared and optimized for a 100 kW cooling load. Variables include the use or lack of an interface heat exchanger, and different operating fluids. Optimization of system mass to radiator rejection temperature is performed. The results indicate a relatively small sensitivity of Rankine cycle system mass to these variables, with optimized system masses of about 6000 kg for the 100 kW thermal load. It is quantitaively demonstrated that absorption based systems are not mass competitive with Rankine systems.

THE 2-3 kHz HELIOSPHERIC RADIATION, THE IBEX RIBBON, AND THE THREE-DIMENSIONAL SHAPE OF THE HELIOPAUSE

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

Fuselier, Stephen A.; Cairns, Iver H.

2013-07-10

Recent Interstellar Boundary Explorer (IBEX) observations indicate that the total dynamic pressure in the interstellar medium is closely partitioned between the plasma and the magnetic field, with an Alfven Mach number M{sub A} {approx} 1 and a sonic Mach number {approx}2. Observations of the IBEX Ribbon provide a unique determination of the orientation of the undraped interstellar magnetic field along the heliopause. There is also a striking correspondence between the Ribbon location and the source locations of 2-3 kHz radiation determined from Voyager observations: the radiation sources north of the ecliptic form a line parallel to but offset by aboutmore » 30 Degree-Sign from the Ribbon. A general Rankine-Hugoniot analysis is used to argue that the heliopause should not be symmetric about the velocity vector V{sub ISM} of the interstellar medium relative to the Sun (the nominal nose direction). Furthermore, the closest point on the heliopause to the Sun should be on the Ribbon for M{sub A} = 0 and at least 9 Degree-Sign from the nominal nose direction toward the Ribbon for M{sub A} = 1. These new results are combined into a conceptual model of the heliopause that includes (1) a plasma depletion layer formed as the interstellar magnetic field drapes against the heliopause, (2) a minimum inner heliosheath thickness and closest point between the Sun and heliopause along (or close to) the Ribbon rather than in the nominal nose direction (along V{sub ISM}), and (3) inference of an asymmetric heliopause shape from the angular offset of the radio sources and Ribbon and from the Rankine-Hugoniot analysis.« less

A multi-objective optimization approach for the selection of working fluids of geothermal facilities: Economic, environmental and social aspects.

PubMed

Martínez-Gomez, Juan; Peña-Lamas, Javier; Martín, Mariano; Ponce-Ortega, José María

2017-12-01

The selection of the working fluid for Organic Rankine Cycles has traditionally been addressed from systematic heuristic methods, which perform a characterization and prior selection considering mainly one objective, thus avoiding a selection considering simultaneously the objectives related to sustainability and safety. The objective of this work is to propose a methodology for the optimal selection of the working fluid for Organic Rankine Cycles. The model is presented as a multi-objective approach, which simultaneously considers the economic, environmental and safety aspects. The economic objective function considers the profit obtained by selling the energy produced. Safety was evaluated in terms of individual risk for each of the components of the Organic Rankine Cycles and it was formulated as a function of the operating conditions and hazardous properties of each working fluid. The environmental function is based on carbon dioxide emissions, considering carbon dioxide mitigation, emission due to the use of cooling water as well emissions due material release. The methodology was applied to the case of geothermal facilities to select the optimal working fluid although it can be extended to waste heat recovery. The results show that the hydrocarbons represent better solutions, thus among a list of 24 working fluids, toluene is selected as the best fluid. Copyright © 2017 Elsevier Ltd. All rights reserved.

COMPARISON OF THERMAL EFFICIENCIES FOR A MERCURY-STEAM BINARY VAPOR CYCLE AND THE RANKINE CYCLE

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

Prem, L.L.

1961-05-19

A comparison of the thermal efficiencies of the mercurysteam binary vapor cycle and the Rankine cycle shows that the binary cycle efficiency is greater. A temperatureentropy diagram and a schematic layout of the binary cycle are presented for clarity. (N.W.R.)

Current Status of an Organic Rankine Cycle Engine Development Program

NASA Technical Reports Server (NTRS)

Barber, R. E.

1984-01-01

The steps taken to achieve improved bearing life in the organic Rankine cycle (ORC) engine being developed for use on solar parabolic dishes are presented. A summary of test results is given. Dynamic tests on the machine shaft and rotors of the ORC engine are also discussed.

Pedagogical Methods of Teaching "Women in Public Speaking."

ERIC Educational Resources Information Center

Pederson, Lucille M.

A course on women in public speaking, developed at the University of Cincinnati, focuses on the rhetoric of selected women who have been involved in various movements and causes in the United States in the twentieth century. Women studied include educator Mary McLeod Bethune, Congresswoman Jeannette Rankin, suffragette Carrie Chapman Catt, Helen…

Organic rankine cycle fluid

DOEpatents

Brasz, Joost J.; Jonsson, Ulf J.

2006-09-05

A method of operating an organic rankine cycle system wherein a liquid refrigerant is circulated to an evaporator where heat is introduced to the refrigerant to convert it to vapor. The vapor is then passed through a turbine, with the resulting cooled vapor then passing through a condenser for condensing the vapor to a liquid. The refrigerant is one of CF.sub.3CF.sub.2C(O)CF(CF.sub.3).sub.2, (CF.sub.3).sub.2 CFC(O)CF(CF.sub.3).sub.2, CF.sub.3(CF.sub.2).sub.2C(O)CF(CF.sub.3).sub.2, CF.sub.3(CF.sub.2).sub.3C(O)CF(CG.sub.3).sub.2, CF.sub.3(CF.sub.2).sub.5C(O)CF.sub.3, CF.sub.3CF.sub.2C(O)CF.sub.2CF.sub.2CF.sub.3, CF.sub.3C(O)CF(CF.sub.3).sub.2.

Utilization of waste heat in trucks for increased fuel economy

NASA Technical Reports Server (NTRS)

Leising, C. J.; Purohit, G. P.; Degrey, S. P.; Finegold, J. G.

1978-01-01

Improvements in fuel economy for a broad spectrum of truck engines and waste heat utilization concepts are evaluated and compared. The engines considered are the diesel, spark ignition, gas turbine, and Stirling. The waste heat utilization concepts include preheating, regeneration, turbocharging, turbocompounding, and Rankine engine compounding. Predictions were based on fuel-air cycle analyses, computer simulation, and engine test data. The results reveal that diesel driving cycle performance can be increased by 20% through increased turbocharging, turbocompounding, and Rankine engine compounding. The Rankine engine compounding provides about three times as much improvement as turbocompounding but also costs about three times as much. Performance for either is approximately doubled if applied to an adiabatic diesel.

Doors Open

ERIC Educational Resources Information Center

Melia, Ed

2008-01-01

Not all of crime writer Ian Rankin's inspiration comes from Edinburgh's mean streets. When it came to writing a Quick Read--one of the short, fast-paced books for reluctant, returning or emergent readers--the Beach Boys provided the unlikely germ for an idea. Despite his success and obvious delight and energy for writing, Rankin admits to being a…

The Influence of Campus Climate and Urbanization on Queer-Spectrum and Trans-Spectrum Faculty Intent to Leave

ERIC Educational Resources Information Center

Garvey, Jason C.; Rankin, Susan

2018-01-01

Prior scholarship offers that queer-spectrum and trans-spectrum faculty often experience hostile and uninviting institutional climates (Bilimoria & Stewart, 2009; Rankin, 2003; Sears, 2002). The results of a 2010 study (Rankin, Weber, Blumenfeld, & Frazer, 2010) suggest that these experiences may lead lesbian, gay, bisexual, transgender,…

Technical and economic study of Stirling and Rankine cycle bottoming systems for heavy truck diesel engines

NASA Technical Reports Server (NTRS)

Kubo, I.

1987-01-01

Bottoming cycle concepts for heavy duty transport engine applications were studied. In particular, the following tasks were performed: (1) conceptual design and cost data development for Stirling systems; (2) life-cycle cost evaluation of three bottoming systems - organic Rankine, steam Rankine, and Stirling cycles; and (3) assessment of future directions in waste heat utilization research. Variables considered for the second task were initial capital investments, fuel savings, depreciation tax benefits, salvage values, and service/maintenance costs. The study shows that none of the three bottoming systems studied are even marginally attractive. Manufacturing costs have to be reduced by at least 65%. As a new approach, an integrated Rankine/Diesel system was proposed. It utilizes one of the diesel cylinders as an expander and capitalizes on the in-cylinder heat energy. The concept eliminates the need for the power transmission device and a sophisticated control system, and reduces the size of the exhaust evaporator. Results of an economic evaluation indicate that the system has the potential to become an attractive package for end users.

Dual-objective optimization of organic Rankine cycle (ORC) systems using genetic algorithm: a comparison between basic and recuperative cycles

NASA Astrophysics Data System (ADS)

Hayat, Nasir; Ameen, Muhammad Tahir; Tariq, Muhammad Kashif; Shah, Syed Nadeem Abbas; Naveed, Ahmad

2017-08-01

Exploitation of low potential waste thermal energy for useful net power output can be done by manipulating organic Rankine cycle systems. In the current article dual-objectives (η_{th} and SIC) optimization of ORC systems [basic organic Rankine cycle (BORC) and recuperative organic Rankine cycle (RORC)] has been done using non-dominated sorting genetic algorithm (II). Seven organic compounds (R-123, R-1234ze, R-152a, R-21, R-236ea, R-245ca and R-601) have been employed in basic cycle and four dry compounds (R-123, R-236ea, R-245ca and R-601) have been employed in recuperative cycle to investigate the behaviour of two systems and compare their performance. Sensitivity analyses show that recuperation boosts the thermodynamic behaviour of systems but it also raises specific investment cost significantly. R-21, R-245ca and R-601 show attractive performance in BORC whereas R-601 and R-236ea in RORC. RORC, due to higher total investment cost and operation & maintenance costs, has longer payback periods as compared to BORC.

Estimating the neutrally buoyant energy density of a Rankine-cycle/fuel-cell underwater propulsion system

NASA Astrophysics Data System (ADS)

Waters, Daniel F.; Cadou, Christopher P.

2014-02-01

A unique requirement of underwater vehicles' power/energy systems is that they remain neutrally buoyant over the course of a mission. Previous work published in the Journal of Power Sources reported gross as opposed to neutrally-buoyant energy densities of an integrated solid oxide fuel cell/Rankine-cycle based power system based on the exothermic reaction of aluminum with seawater. This paper corrects this shortcoming by presenting a model for estimating system mass and using it to update the key findings of the original paper in the context of the neutral buoyancy requirement. It also presents an expanded sensitivity analysis to illustrate the influence of various design and modeling assumptions. While energy density is very sensitive to turbine efficiency (sensitivity coefficient in excess of 0.60), it is relatively insensitive to all other major design parameters (sensitivity coefficients < 0.15) like compressor efficiency, inlet water temperature, scaling methodology, etc. The neutral buoyancy requirement introduces a significant (∼15%) energy density penalty but overall the system still appears to offer factors of five to eight improvements in energy density (i.e., vehicle range/endurance) over present battery-based technologies.

Infrasonic ray tracing applied to mesoscale atmospheric structures: refraction by hurricanes.

PubMed

Bedard, Alfred J; Jones, R Michael

2013-11-01

A ray-tracing program is used to estimate the refraction of infrasound by the temperature structure of the atmosphere and by hurricanes represented by a Rankine-combined vortex wind plus a temperature perturbation. Refraction by the hurricane winds is significant, giving rise to regions of focusing, defocusing, and virtual sources. The refraction of infrasound by the temperature anomaly associated with a hurricane is small, probably no larger than that from uncertainties in the wind field. The results are pertinent to interpreting ocean wave generated infrasound in the vicinities of tropical cyclones.

Solar power satellite system definition study. Part 1 and part 2, volume 2: Technical summary

NASA Technical Reports Server (NTRS)

1977-01-01

Practical designs for power transmission were developed to meet requirements and constraints. Microwave link error was analyzed to confirm attainability of acceptable link efficiency. Silicon photovoltaic was determined to be the best overall choice for energy conversion, with a potassium Rankine cycle as the backup choice. Space transportation operations provide low cost because of traffic level, and the payload volume is the launch vehicle design driver. The power cost is 4 to 5 /kwh, which will be competitive with fossil fuel sources by the year 2000.

Phase 1 of the First Solar Small Power System Experiment (experimental System No. 1). Volume 2: Appendix A - D

NASA Technical Reports Server (NTRS)

Clark, T. B. (Editor)

1979-01-01

Recommended conceptual designs for the baseline solar concentrator and electrical subsystems are defined, and trade offs that were evaluated to arrive at the baseline systems are presented. In addition, the developmental history of the Stirling engine is reviewed, the U4 configuration is described, and a Stirling engine heat pipe system is evaluated for solar application where sodium vapor is used as the heat source. An organic Rankine cycle engine is also evaluated for solar small power system application.

Theoretical evaluation of the vapor compression cycle with a liquid-line/suction-line heat exchanger, economizer, and ejector

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

Domanski, P.A.

1995-03-01

The report presents a theoretical analysis of three vapor compression cycles which are derived from the Rankine cycle by incorporating a liquid-line/suction-line heat exchanger, economizer, or ejector. These addendums to the basic cycle reduce throttling losses using different principles, and they require different mechanical hardware of different complexity and cost. The theoretical merits of the three modified cycles were evaluated in relation to the reversed Carnot and Rankine cycle. Thirty-eight fluids were included in the study using the Carnahan-Starling-DeSantis equation of state. In general, the benefit of these addendums increases with the amount of the throttling losses realized by themore » refrigerant in the Rankine cycle.« less

The resolved layer of a collisionless, high beta, supercritical, quasi-perpendicular shock wave. I - Rankine-Hugoniot geometry, currents, and stationarity

NASA Technical Reports Server (NTRS)

Scudder, J. D.; Aggson, T. L.; Mangeney, A.; Lacombe, C.; Harvey, C. C.

1986-01-01

Data collected by the ISEE dual-spacecraft mission (on November 7, 1977) on a slowly moving, supercritical, high-beta, quasi-perpendicular bow shock are presented, and the local geometry, spatial scales, and stationarity of this shock wave are assessed in a self-consistent Rankine-Hugoniot-constrained frame of reference. Included are spatial profiles of the ac and dc magnetic and electric fields, electron and proton fluid velocities, current densities, electron and proton number densities, temperatures, pressures, and partial densities of the reflected protons. The observed layer profile is shown to be nearly phase standing and one-dimensional in a Rankine-Hugoniot frame, empirically determined by the magnetofluid parameters outside the layer proper.

The development of an air Brayton and a steam Rankine solar receiver

NASA Technical Reports Server (NTRS)

Greeven, M. V.

1980-01-01

An air Brayton and a steam Rankine solar receiver now under development are described. These cavity receivers accept concentrated insolation from a single point focus, parabolic concentrator, and use this energy to heat the working fluid. Both receivers were designed for a solar input of 85 kw. The air Brayton receiver heats the air to 816 C. A metallic plate-fin heat transfer surface is used in this unit to effect the energy transfer. The steam Rankine receiver was designed as a once-through boiler with reheat. The receiver heats the water to 704 C to produce steam at 17.22 MPa in the boiler section. The reheat section operates at 1.2 MPA, reheating the steam to 704 C.

Solar power satellite system definition study. Part 2, volume 5: Space operations (construction and transportation)

NASA Technical Reports Server (NTRS)

Miller, K.; Davis, E. E.

1977-01-01

Construction and transportation systems and operations are described for the following combinations: (1) silicon photovoltaic CR=1 satellite constructed primarily in low earth orbit (LEO); (2) silicon photovoltaic CR=1 satellite constructed in geosynchronous earth orbit (GEO); (3) Rankine thermal engine satellite constructed primarily in LEO; and (4) Rankine thermal engine satellite constructed in GEO.

Utilization of waste heat in trucks for increased fuel economy

NASA Technical Reports Server (NTRS)

Leising, C. J.; Purohit, G. P.; Degrey, S. P.; Finegold, J. G.

1978-01-01

The waste heat utilization concepts include preheating, regeneration, turbocharging, turbocompounding, and Rankine engine compounding. Predictions are based on fuel-air cycle analyses, computer simulation, and engine test data. All options are evaluated in terms of maximum theoretical improvements, but the Diesel and adiabatic Diesel are also compared on the basis of maximum expected improvement and expected improvement over a driving cycle. The study indicates that Diesels should be turbocharged and aftercooled to the maximum possible level. The results reveal that Diesel driving cycle performance can be increased by 20% through increased turbocharging, turbocompounding, and Rankine engine compounding. The Rankine engine compounding provides about three times as much improvement as turbocompounding but also costs about three times as much. Performance for either can be approximately doubled if applied to an adiabatic Diesel.

Concentrating Solar Power Projects - La Africana | Concentrating Solar

Science.gov Websites

: Posadas (Córdoba) Owner(s): Ortiz/TSK/Magtel (100%) Technology: Parabolic trough Turbine Capacity: Net -Field Outlet Temp: 393°C Solar-Field Temp Difference: 100°C Power Block Turbine Capacity (Gross): 50.0 MW Turbine Capacity (Net): 50.0 MW Output Type: Steam Rankine Cooling Method: Wet cooling Thermal

A quantitative risk-assessment system (QR-AS) evaluating operation safety of Organic Rankine Cycle using flammable mixture working fluid.

PubMed

Tian, Hua; Wang, Xueying; Shu, Gequn; Wu, Mingqiang; Yan, Nanhua; Ma, Xiaonan

2017-09-15

Mixture of hydrocarbon and carbon dioxide shows excellent cycle performance in Organic Rankine Cycle (ORC) used for engine waste heat recovery, but the unavoidable leakage in practical application is a threat for safety due to its flammability. In this work, a quantitative risk assessment system (QR-AS) is established aiming at providing a general method of risk assessment for flammable working fluid leakage. The QR-AS covers three main aspects: analysis of concentration distribution based on CFD simulations, explosive risk assessment based on the TNT equivalent method and risk mitigation based on evaluation results. A typical case of propane/carbon dioxide mixture leaking from ORC is investigated to illustrate the application of QR-AS. According to the assessment results, proper ventilation speed, safe mixture ratio and location of gas-detecting devices have been proposed to guarantee the security in case of leakage. The results revealed that this presented QR-AS was reliable for the practical application and the evaluation results could provide valuable guidance for the design of mitigation measures to improve the safe performance of ORC system. Copyright © 2017 Elsevier B.V. All rights reserved.

An analytical study on the performance of the organic Rankine cycle for turbofan engine exhaust heat recovery

NASA Astrophysics Data System (ADS)

Saadon, S.; Abu Talib, A. R.

2016-10-01

Due to energy shortage and global warming, issues of energy saving have become more important. To increase the energy efficiency and reduce the fuel consumption, waste heat recovery is a significant method for energy saving. The organic Rankine cycle (ORC) has great potential to recover the waste heat from the core jet exhaust of a turbofan engine and use it to produce power. Preliminary study of the design concept and thermodynamic performance of this ORC system would assist researchers to predict the benefits of using the ORC system to extract the exhaust heat engine. In addition, a mathematical model of the heat transfer of this ORC system is studied and developed. The results show that with the increment of exhaust heat temperature, the mass flow rate of the working fluid, net power output and the system thermal efficiency will also increase. Consequently, total consumption of jet fuel could be significantly saved as well.

Alkali Metal Rankine Cycle Boiler Technology Challenges and Some Potential Solutions for Space Nuclear Power and Propulsion Applications

NASA Technical Reports Server (NTRS)

Stone, James R.

1994-01-01

Alkali metal boilers are of interest for application to future space Rankine cycle power conversion systems. Significant progress on such boilers was accomplished in the 1960's and early 1970's, but development was not continued to operational systems since NASA's plans for future space missions were drastically curtailed in the early 1970's. In particular, piloted Mars missions were indefinitely deferred. With the announcement of the Space Exploration Initiative (SEI) in July 1989 by President Bush, interest was rekindled in challenging space missions and, consequently in space nuclear power and propulsion. Nuclear electric propulsion (NEP) and nuclear thermal propulsion (NTP) were proposed for interplanetary space vehicles, particularly for Mars missions. The potassium Rankine power conversion cycle became of interest to provide electric power for NEP vehicles and for 'dual-mode' NTP vehicles, where the same reactor could be used directly for propulsion and (with an additional coolant loop) for power. Although the boiler is not a major contributor to system mass, it is of critical importance because of its interaction with the rest of the power conversion system; it can cause problems for other components such as excess liquid droplets entering the turbine, thereby reducing its life, or more critically, it can drive instabilities-some severe enough to cause system failure. Funding for the SEI and its associated technology program from 1990 to 1993 was not sufficient to support significant new work on Rankine cycle boilers for space applications. In Fiscal Year 1994, funding for these challenging missions and technologies has again been curtailed, and planning for the future is very uncertain. The purpose of this paper is to review the technologies developed in the 1960's and 1970's in the light of the recent SEI applications. In this way, future Rankine cycle boiler programs may be conducted most efficiently. This report is aimed at evaluating alkali metal boiler technology for space Rankine cycle systems. Research is summarized on the problems of flow stability, liquid carryover, pressure drop and heat transfer, and on potential solutions developed, primarily those developed by the NASA Lewis Research Center in the 1960's and early 1970's.

Innovative open air brayton combined cycle systems for the next generation nuclear power plants

NASA Astrophysics Data System (ADS)

Zohuri, Bahman

The purpose of this research was to model and analyze a nuclear heated multi-turbine power conversion system operating with atmospheric air as the working fluid. The air is heated by a molten salt, or liquid metal, to gas heat exchanger reaching a peak temperature of 660 0C. The effects of adding a recuperator or a bottoming steam cycle have been addressed. The calculated results are intended to identify paths for future work on the next generation nuclear power plant (GEN-IV). This document describes the proposed system in sufficient detail to communicate a good understanding of the overall system, its components, and intended uses. The architecture is described at the conceptual level, and does not replace a detailed design document. The main part of the study focused on a Brayton --- Rankine Combined Cycle system and a Recuperated Brayton Cycle since they offer the highest overall efficiencies. Open Air Brayton power cycles also require low cooling water flows relative to other power cycles. Although the Recuperated Brayton Cycle achieves an overall efficiency slightly less that the Brayton --- Rankine Combined Cycle, it is completely free of a circulating water system and can be used in a desert climate. Detailed results of modeling a combined cycle Brayton-Rankine power conversion system are presented. The Rankine bottoming cycle appears to offer a slight efficiency advantage over the recuperated Brayton cycle. Both offer very significant advantages over current generation Light Water Reactor steam cycles. The combined cycle was optimized as a unit and lower pressure Rankine systems seem to be more efficient. The combined cycle requires a lot less circulating water than current power plants. The open-air Brayton systems appear to be worth investigating, if the higher temperatures predicted for the Next Generation Nuclear Plant do materialize.

Global Value Chain and Manufacturing Analysis on Geothermal Power Plant Turbines

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

Akar, Sertac; Augustine, Chad; Kurup, Parthiv

In this study, we have undertaken a robust analysis of the global supply chain and manufacturing costs for components of Organic Rankine Cycle (ORC) Turboexpander and steam turbines used in geothermal power plants. We collected a range of market data influencing manufacturing from various data sources and determined the main international manufacturers in the industry. The data includes the manufacturing cost model to identify requirements for equipment, facilities, raw materials, and labor. We analyzed three different cases; 1) 1 MW geothermal ORC Turboexpander 2) 5 MW ORC Turboexpander 3) 20 MW geothermal Steam Turbine

Exergy analysis and optimisation of waste heat recovery systems for cement plants

NASA Astrophysics Data System (ADS)

Mohammadi, Amin; Ashjari, Muhammad Ali; Sadreddini, Amirhassan

2018-02-01

In the last decades, heat recovery systems have received much attention due to the increase in fuel cost and the increase in environmental issues. In this study, different heat recovery systems for a cement plant are compared in terms of electricity generation and exergy analysis. The heat sources are available in high temperature (HT) and low temperature (LT). For the HT section a dual pressure Rankine cycle, a simple dual pressure Organic Rankine Cycle (ORC) and a regenerative dual pressure ORC are compared. Also, for the LT section, a simple ORC is compared with transcritical carbon dioxide cycle. To find the best system, an optimisation algorithm is applied to all proposed cycles. The results show that for the HT section, regenerative ORC has the highest exergy efficiency and has the capability of producing nearly 7 MW electricity for a cement factory with the capacity of 3400 ton per day. The main reason for this is introducing the regenerative heat exchanger to the cycle. For the LT section, ORC showed a better performance than the CO2 cycle. It is worth mentioning that the generated power in this section is far lower than that of the HT section and is equal to nearly 300 kW.

Exergy analysis of biomass organic Rankine cycle for power generation

NASA Astrophysics Data System (ADS)

Nur, T. B.; Sunoto

2018-02-01

The study examines proposed small biomass-fed Organic Rankine Cycle (ORC) power plant through exergy analysis. The system consists of combustion burner unit to utilize biomass as fuel, and organic Rankine cycle unit to produce power from the expander. The heat from combustion burner was transfered by thermal oil heater to evaporate ORC working fluid in the evaporator part. The effects of adding recuperator into exergy destruction were investigated. Furthermore, the results of the variations of system configurations with different operating parameters, such as the evaporating pressures, ambient temperatures, and expander pressures were analyzed. It was found that the largest exergy destruction occurs during processes are at combustion part, followed by evaporator, condenser, expander, and pump. The ORC system equipped with a recuperator unit exhibited good operational characteristics under wide range conditions compared to the one without recuperator.

The design of components for an advanced Rankine cycle test facility.

NASA Technical Reports Server (NTRS)

Bond, J. A.

1972-01-01

The design of a facility for testing components of an advanced Rankine cycle power system is summarized. The facility is a three-loop system in which lithium, potassium and NaK-78 are the working fluids of the primary, secondary and heat-rejection loops, respectively. Design bases and performance predictions for the major loop components, including the lithium heater and the potassium boiler, condenser and preheater, are outlined.

T-111 Rankine system corrosion test loop, volume 1

NASA Technical Reports Server (NTRS)

Harrison, R. W.; Hoffman, E. E.; Smith, J. P.

1975-01-01

Results are given of a program whose objective was to determine the performance of refractory metal alloys in a two loop Rankine test system. The test system consisted of a circulating lithium circuit heated to 1230 C maximum transferring heat to a boiling potassium circuit with a 1170 C superheated vapor temperature. The results demonstrate the suitability of the selected refractory alloys to perform from a chemical compatibility standpoint.

Research in Support of the Use of Rankine Cycle Energy Conversion Systems for Space Power and Propulsion

NASA Technical Reports Server (NTRS)

Lahey, Richard T., Jr.; Dhir, Vijay

2004-01-01

This is the report of a Scientific Working Group (SWG) formed by NASA to determine the feasibility of using a liquid metal cooled nuclear reactor and Rankine energy conversion cycle for dual purpose power and propulsion in space. This is a high level technical report which is intended for use by NASA management in program planning. The SWG was composed of a team of specialists in nuclear energy and multiphase flow and heat transfer technology from academia, national laboratories, NASA and industry. The SWG has identified the key technology issues that need to be addressed and have recommended an integrated short term (approx. 2 years) and a long term (approx. 10 year) research and development (R&D) program to qualify a Rankine cycle power plant for use in space. This research is ultimately intended to give NASA and its contractors the ability to reliably predict both steady and transient multiphase flow and heat transfer phenomena at reduced gravity, so they can analyze and optimize designs and scale-up experimental data on Rankine cycle components and systems. In addition, some of these results should also be useful for the analysis and design of various multiphase life support and thermal management systems being considered by NASA.

Vibration Test of a SNAP-8 Sodium-Potassium Alloy Pump

NASA Image and Video Library

1970-01-21

Aeronautics and Space Administration (NASA) Lewis Research Center. Aerojet General was contracted to design the SNAP-8 generator which employed a mercury Rankine system to convert the reactor’s heat into electrical power. The hermetically-sealed pump was designed to generate from 35 to 90 kilowatts of electrical power. In 1964 a SNAP-8 test rig with a mercury boiler and condenser was set up in cell W-1 of Lewis’ Engine Research Building to study the transients in the system’s three loops. In 1967 a complete Rankine system was operated for 60 days in W-1 to verify the integrity of the Lewis-developed mercury boiler. Further tests in 1969 verified the shutdown and startup of the system under normal and emergency conditions. Aerojet operated the first full-Rankine system in June 1966 and completed a 2500-hour endurance test in early 1969. Lewis and Aerojet’s success on the Rankine system was acknowledged with NASA Group Achievement Award in November 1970. The 1970 vibration tests, seen here, were conducted in Lewis’ Engine Research Building’s environmental laboratory. The testing replicated the shock and vibration expected to occur during the launch into space and subsequent maneuvering. The pump was analyzed on each of its major axes.

Application of solar energy to air conditioning systems

NASA Technical Reports Server (NTRS)

Nash, J. M.; Harstad, A. J.

1976-01-01

The results of a survey of solar energy system applications of air conditioning are summarized. Techniques discussed are both solar powered (absorption cycle and the heat engine/Rankine cycle) and solar related (heat pump). Brief descriptions of the physical implications of various air conditioning techniques, discussions of status, proposed technological improvements, methods of utilization and simulation models are presented, along with an extensive bibliography of related literature.

Parametric Adjustments to the Rankine Vortex Wind Model for Gulf of Mexico Hurricanes

DTIC Science & Technology

2012-11-01

2012 4. TITLE AND SUBTITLE Parametric Adjustments to the Rankine Vortex Wind Model for Gulf of Mexico Hurricanes 5a. CONTRACT NUMBER 5b. GRANT ...may be used to construct spatially varying wind fields for the GOM region (e.g., Thompson and Cardone [12]), but this requires using a complicated...Storm Damage Reduc- tion, and Dredging Operations and Environmental Research (DOER). The USACE Headquarters granted permission to publish this paper

Potassium Rankine cycle vapor chamber (heat pipe) radiator study

NASA Technical Reports Server (NTRS)

Gerrels, E. E.; Killen, R. E.

1971-01-01

A structurally integrated vapor chamber fin (heat pipe) radiator is defined and evaluated as a potential candidate for rejecting waste heat from the potassium Rankine cycle powerplant. Several vapor chamber fin geometries, using stainless steel construction, are evaluated and an optimum is selected. A comparison is made with an operationally equivalent conduction fin radiator. Both radiators employ NaK-78 in the primary coolant loop. In addition, the Vapor Chamber Fin (VCF) radiator utilizes sodium in the vapor chambers. Preliminary designs are developed for the conduction fin and VCF concepts. Performance tests on a single vapor chamber were conducted to verify the VCF design. A comparison shows the conduction fin radiator easier to fabricate, but heavier in weight, particularly as meteoroid protection requirements become more stringent. While the analysis was performed assuming the potassium Rankine cycle powerplant, the results are equally applicable to any system radiating heat to space in the 900 to 1400 F temperature range.

Rankine-Brayton engine powered solar thermal aircraft

DOEpatents

Bennett, Charles L [Livermore, CA

2009-12-29

A solar thermal powered aircraft powered by heat energy from the sun. A Rankine-Brayton hybrid cycle heat engine is carried by the aircraft body for producing power for a propulsion mechanism, such as a propeller or other mechanism for enabling sustained free flight. The Rankine-Brayton engine has a thermal battery, preferably containing a lithium-hydride and lithium mixture, operably connected to it so that heat is supplied from the thermal battery to a working fluid. A solar concentrator, such as reflective parabolic trough, is movably connected to an optically transparent section of the aircraft body for receiving and concentrating solar energy from within the aircraft. Concentrated solar energy is collected by a heat collection and transport conduit, and heat transported to the thermal battery. A solar tracker includes a heliostat for determining optimal alignment with the sun, and a drive motor actuating the solar concentrator into optimal alignment with the sun based on a determination by the heliostat.

Decreasing the Thermal Load on the Environment with the Help of Thermal Pumps in the Sewage Treatment System

NASA Astrophysics Data System (ADS)

Lozovetskii, V. V.; Lebedev, V. V.; Cherkina, V. M.; Ivanchuk, M. S.

2018-05-01

We propose designs for practical use of residual heat of sewage by means of thermal-pump transformation of thermal energy in plants operating on inverse Rankine and Lorentz cycles, as well as a method for sewage heat removal in drainage canals of water removal systems based on the application of double-pipe heat exchangers known as Field tubes.

Decreasing the Thermal Load on the Environment with the Help of Thermal Pumps in the Sewage Treatment System

NASA Astrophysics Data System (ADS)

Lozovetskii, V. V.; Lebedev, V. V.; Cherkina, V. M.; Ivanchuk, M. S.

2018-03-01

We propose designs for practical use of residual heat of sewage by means of thermal-pump transformation of thermal energy in plants operating on inverse Rankine and Lorentz cycles, as well as a method for sewage heat removal in drainage canals of water removal systems based on the application of double-pipe heat exchangers known as Field tubes.

Energy recovery system using an organic rankine cycle

DOEpatents

Ernst, Timothy C

2013-10-01

A thermodynamic system for waste heat recovery, using an organic rankine cycle is provided which employs a single organic heat transferring fluid to recover heat energy from two waste heat streams having differing waste heat temperatures. Separate high and low temperature boilers provide high and low pressure vapor streams that are routed into an integrated turbine assembly having dual turbines mounted on a common shaft. Each turbine is appropriately sized for the pressure ratio of each stream.

How Should Energy Be Defined Throughout Schooling?

NASA Astrophysics Data System (ADS)

Bächtold, Manuel

2017-02-01

The question of how to teach energy has been renewed by recent studies focusing on the learning and teaching progressions for this concept. In this context, one question has been, for the most part, overlooked: how should energy be defined throughout schooling? This paper addresses this question in three steps. We first identify and discuss two main approaches in physics concerning the definition of energy, one claiming there is no satisfactory definition and taking conservation as a fundamental property, and the other based on Rankine's definition of energy as the capacity of a system to produce changes. We then present a study concerning how energy is actually defined throughout schooling in the case of France by analyzing national programs, physics textbooks, and the answers of teachers to a questionnaire. This study brings to light a consistency problem in the way energy is defined across school years: in primary school, an adapted version of Rankine's definition is introduced and conservation is ignored; in high school, conservation is introduced and Rankine's definition is ignored. Finally, we address this consistency problem by discussing possible teaching progressions. We argue in favor of the use of Rankine's definition throughout schooling: at primary school, it is a possible substitute to students' erroneous conceptions; at secondary school, it might help students become aware of the unifying role of energy and thereby overcome the compartmentalization problem.

Multi-Megawatt Power System Trade Study

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

Longhurst, Glen Reed; Schnitzler, Bruce Gordon; Parks, Benjamin Travis

2001-11-01

As part of a larger task, the Idaho National Engineering and Environmental Laboratory (INEEL) was tasked to perform a trade study comparing liquid-metal cooled reactors having Rankine power conversion systems with gas-cooled reactors having Brayton power conversion systems. This report summarizes the approach, the methodology, and the results of that trade study. Findings suggest that either approach has the possibility to approach the target specific mass of 3-5 kg/kWe for the power system, though it appears either will require improvements to achieve that. Higher reactor temperatures have the most potential for reducing the specific mass of gas-cooled reactors but domore » not necessarily have a similar effect for liquid-cooled Rankine systems. Fuels development will be the key to higher reactor operating temperatures. Higher temperature turbines will be important for Brayton systems. Both replacing lithium coolant in the primary circuit with gallium and replacing potassium with sodium in the power loop for liquid systems increase system specific mass. Changing the feed pump turbine to an electric motor in Rankine systems has little effect. Key technologies in reducing specific mass are high reactor and radiator operating temperatures, low radiator areal density, and low turbine/generator system masses. Turbine/generator mass tends to dominate overall power system mass for Rankine systems. Radiator mass was dominant for Brayton systems.« less

A combined power and ejector refrigeration cycle for low temperature heat sources

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

Zheng, B.; Weng, Y.W.

A combined power and ejector refrigeration cycle for low temperature heat sources is under investigation in this paper. The proposed cycle combines the organic Rankine cycle and the ejector refrigeration cycle. The ejector is driven by the exhausts from the turbine to produce power and refrigeration simultaneously. A simulation was carried out to analyze the cycle performance using R245fa as the working fluid. A thermal efficiency of 34.1%, an effective efficiency of 18.7% and an exergy efficiency of 56.8% can be obtained at a generating temperature of 395 K, a condensing temperature of 298 K and an evaporating temperature ofmore » 280 K. Simulation results show that the proposed cycle has a big potential to produce refrigeration and most exergy losses take place in the ejector. (author)« less

Biodiversity and spatial patterns of benthic habitat and associated demersal fish communities at two tropical submerged reef ecosystems

NASA Astrophysics Data System (ADS)

Abdul Wahab, Muhammad Azmi; Radford, Ben; Cappo, Mike; Colquhoun, Jamie; Stowar, Marcus; Depczynski, Martial; Miller, Karen; Heyward, Andrew

2018-06-01

Submerged reef ecosystems can be very diverse and may serve as important refugia for shallow-water conspecifics. This study quantified the benthic and fish communities of two proximate, predominantly mesophotic coral ecosystems (MCEs), Glomar Shoal and Rankin Bank, which are geographically isolated from other similar features in the region. Glomar Shoal is identified as a key ecological feature (KEF) in the North West Marine Region of Australia. Multibeam surveys were performed to characterise the seafloor and to derive secondary environmental variables, used to explain patterns in benthic and fish communities. Towed video surveys quantified benthic cover, and stereo baited remote underwater stations were used to survey fish abundance and diversity. Surveys were completed in depths of 20-115 m. The two MCEs exhibited distinct communities; Rankin Bank consistently had higher cover (up to 30×) of benthic taxa across depths, and fish communities that were twice as abundant and 1.5× more diverse than Glomar Shoal. The location of the MCEs, depth and rugosity were most influential in structuring benthic communities. Phototrophic taxa, specifically macroalgae and hard corals, had up to 22 × higher cover at Rankin Bank than at Glomar Shoal and were dominant to 80 m (compared to 60 m at Glomar Shoal), presumably due to greater light penetration (lower turbidity) and lower sand cover at greater depths. The 20% coral cover at Rankin Bank was comparable to that reported for shallow reefs. The cover of sand, hard corals and sponges influenced fish communities, with higher abundance and diversity of fish associated with shallow hard coral habitats. This study demonstrated that the two MCEs were unique within the local context, and when coupled with their geographical isolation and biodiversity, presents compelling support for the additional recognition of Rankin Bank as a KEF.

Adopting a Patient-Centered Approach to Primary Outcome Analysis of Acute Stroke Trials by Use of a Utility-Weighted Modified Rankin Scale

PubMed Central

Chaisinanunkul, Napasri; Adeoye, Opeolu; Lewis, Roger J.; Grotta, James C.; Broderick, Joseph; Jovin, Tudor G.; Nogueira, Raul G.; Elm, Jordan; Graves, Todd; Berry, Scott; Lees, Kennedy R.; Barreto, Andrew D.; Saver, Jeffrey L.

2015-01-01

Background and Purpose Although the modified Rankin Scale (mRS) is the most commonly employed primary endpoint in acute stroke trials, its power is limited when analyzed in dichotomized fashion and its indication of effect size challenging to interpret when analyzed ordinally. Weighting the seven Rankin levels by utilities may improve scale interpretability while preserving statistical power. Methods A utility weighted mRS (UW-mRS) was derived by averaging values from time-tradeoff (patient centered) and person-tradeoff (clinician centered) studies. The UW-mRS, standard ordinal mRS, and dichotomized mRS were applied to 11 trials or meta-analyses of acute stroke treatments, including lytic, endovascular reperfusion, blood pressure moderation, and hemicraniectomy interventions. Results Utility values were: mRS 0–1.0; mRS 1 - 0.91; mRS 2 - 0.76; mRS 3 - 0.65; mRS 4 - 0.33; mRS 5 & 6 - 0. For trials with unidirectional treatment effects, the UW-mRS paralleled the ordinal mRS and outperformed dichotomous mRS analyses. Both the UW-mRS and the ordinal mRS were statistically significant in six of eight unidirectional effect trials, while dichotomous analyses were statistically significant in two to four of eight. In bidirectional effect trials, both the UW-mRS and ordinal tests captured the divergent treatment effects by showing neutral results whereas some dichotomized analyses showed positive results. Mean utility differences in trials with statistically significant positive results ranged from 0.026 to 0.249. Conclusion A utility-weighted mRS performs similarly to the standard ordinal mRS in detecting treatment effects in actual stroke trials and ensures the quantitative outcome is a valid reflection of patient-centered benefits. PMID:26138130

Details of a prospective protocol for a collaborative meta-analysis of individual participant data from all randomized trials of intravenous rt-PA vs. control: statistical analysis plan for the Stroke Thrombolysis Trialists' Collaborative meta-analysis.

PubMed

2013-06-01

Thrombolysis with intravenous alteplase is both effective and safe when administered to particular types of patient within 4·5 hours of having an ischemic stroke. However, the extent to which effects might vary in different types of patient is uncertain. We describe the protocol for an updated individual patient data meta-analysis of trials of intravenous alteplase, including results from the recently reported third International Stroke Trial, in which a wide range of patients enrolled up to six-hours after stroke onset were randomized to alteplase vs. control. This protocol will specify the primary outcome for efficacy, specified prior to knowledge of the results from the third International Stroke Trial, as the proportion of patients having a 'favorable' stroke outcome, defined by modified Rankin Score 0-1 at final follow-up at three- to six-months. The primary analysis will be to estimate the extent to which the known benefit of alteplase on modified Rankin Score 0-1 diminishes with treatment delay, and the extent to which it is independently modified by age and stroke severity. Key secondary outcomes include effect of alteplase on death within 90 days; analyses of modified Rankin Score using ordinal, rather than dichotomous, methods; and effects of alteplase on symptomatic intracranial hemorrhage, fatal intracranial hemorrhage, symptomatic ischemic brain edema and early edema, effacement and/or midline shift. This collaborative meta-analysis of individual participant data from all randomized trials of intravenous alteplase vs. control will demonstrate how the known benefits of alteplase on ischemic stroke outcome vary across different types of patient. © 2013 The Authors. International Journal of Stroke © 2013 World Stroke Organization.

Organic rankine cycle waste heat applications

DOEpatents

Brasz, Joost J.; Biederman, Bruce P.

2007-02-13

A machine designed as a centrifugal compressor is applied as an organic rankine cycle turbine by operating the machine in reverse. In order to accommodate the higher pressures when operating as a turbine, a suitable refrigerant is chosen such that the pressures and temperatures are maintained within established limits. Such an adaptation of existing, relatively inexpensive equipment to an application that may be otherwise uneconomical, allows for the convenient and economical use of energy that would be otherwise lost by waste heat to the atmosphere.

Turbocharger chiller modeling and test evaluation. Final report, March-November 1993

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

Kountz, K.J.; Wurm, J.

1996-07-01

The objectives of this project were: To determine the technoeconomic feasibility of a natural gas-fired turbocharger-based chiller system, arranged in a combined-fluid Rankine/Rankine cycle; To design the turbocharger chiller system for a 50 RT cooling rating point capacity, using available vehicle turbocharges and standard chiller heat exchanger technology; and To evaluate several low, medium, and high pressure refrigerants and refrigerant/lubricant pairs for their thermodynamic and thermal stability characteristics and applicability to the chiller cycle.

Test results of an organic Rankine-cycle power module for a small community solar thermal power experiment

NASA Technical Reports Server (NTRS)

Clark, T. B.

1985-01-01

The organic Rankine-cycle (ORC) power conversion assembly was tested. Qualification testing of the electrical transport subsystem was also completed. Test objectives were to verify compatibility of all system elements with emphasis on control of the power conversion assembly, to evaluate the performance and efficiency of the components, and to validate operating procedures. After 34 hours of power generation under a wide range of conditions, the net module efficiency exceeded 18% after accounting for all parasitic losses.

Evaluation of Coal Gasification/Combined Cycle Power Plant Feasibility at the Sewells Point Naval Complex, Norfolk, Virginia.

DTIC Science & Technology

1981-07-01

2 No. Name Page I 3-2 Rankine Cycle Configuration and Temperature- Entropy Chart 3-6 S 3-3 Brayton Cycle Configuration and Temperature- Entropy Chart...shown in Exhibit 3-1 presents the combined cycle as integrated with the gasification plant, i.e., there is an interchange of electric power, feedwater ...Brayton and Rankine cycles , respectively. The cycle configuration and the temperature-entropy charts for these two cycles are shown in Exhibits 3-2 and 3

Utilization of Indonesia's Hot Spring Sources for Electricity using Kalina Cycle and Organic Rankine Cycle

NASA Astrophysics Data System (ADS)

Prabumukti, Grano; Purwanto; Widodo, Wahyu

2018-02-01

Indonesia posses 40% of the world's geothermal energy sources. The existence of hydrothermal sources is usually characterized by their surface manifestations such as hot springs, geysers and fumarole. Hot spring has a potential to be used as a heat source to generate electricity especially in a rural and isolated area. Hot springs can be converted into electricity by binary thermodynamic cycles such as Kalina cycle and ORC. The aim of this study is to obtain the best performances of cycle configuration and the potential power capacity. Simulation is conducted using UNISIM software with working fluid and its operating condition as the decision variables. The simulation result shows that R1234yf and propene with simple ORC as desired working fluid and cycle configuration. It reaches a maximum thermal efficiency up to 9.6% with a specific turbine inlet pressure. Higher temperature heat source will result a higher thermal efficiency‥ Cycle thermal efficiency varies from 4.7% to 9.6% depends on source of hot spring temperature. Power capacity that can be generated using Indonesia's hot spring is ranged from 2 kWe to 61.2 kWe. The highest capacity located in Kawah Sirung and the least located in Kaendi.

Design and Checkout of a High Speed Research Nozzle Evaluation Rig

NASA Technical Reports Server (NTRS)

Castner, Raymond S.; Wolter, John D.

1997-01-01

The High Flow Jet Exit Rig (HFJER) was designed to provide simulated mixed flow turbojet engine exhaust for one- seventh scale models of advanced High Speed Research test nozzles. The new rig was designed to be used at NASA Lewis Research Center in the Nozzle Acoustic Test Rig and the 8x6 Supersonic Wind Tunnel. Capabilities were also designed to collect nozzle thrust measurement, aerodynamic measurements, and acoustic measurements when installed at the Nozzle Acoustic Test Rig. Simulated engine exhaust can be supplied from a high pressure air source at 33 pounds of air per second at 530 degrees Rankine and nozzle pressure ratios of 4.0. In addition, a combustion unit was designed from a J-58 aircraft engine burner to provide 20 pounds of air per second at 2000 degrees Rankine, also at nozzle pressure ratios of 4.0. These airflow capacities were designed to test High Speed Research nozzles with exhaust areas from eighteen square inches to twenty-two square inches. Nozzle inlet flow measurement is available through pressure and temperature sensors installed in the rig. Research instrumentation on High Speed Research nozzles is available with a maximum of 200 individual pressure and 100 individual temperature measurements. Checkout testing was performed in May 1997 with a 22 square inch ASME long radius flow nozzle. Checkout test results will be summarized and compared to the stated design goals.

Study of toluene stability for an Organic Rankine Cycle (ORC) space-based power system

NASA Technical Reports Server (NTRS)

Havens, Vance; Ragaller, Dana

1988-01-01

The design, fabrication, assembly, and endurance operation of a dynamic test loop, built to evaluate the thermal stability of a proposed Organic Rankine Cycle (ORC) working fluid, is discussed. The test fluid, toluene, was circulated through a heater, simulated turbine, regenerator, condenser and pump to duplicate an actual ORC system. The maximum nominal fluid temperature, 750 F, was at the turbine simulator inlet. Samples of noncondensible gases and liquid toluene were taken periodically during the test. The samples were analyzed to identify the degradation products formed and the quantity of these products. From these data it was possible to determine the degradation rate of the working fluid and the generation rate of noncondensible gases. A further goal of this work was to relate the degradation observed in the dynamic operating loop to degradation obtained in isothermal capsule tests. This relationship was the basis for estimating the power loop degradation in the Space Station Organic Rankine Cycle system.

Microgravity fluid management requirements of advanced solar dynamic power systems

NASA Technical Reports Server (NTRS)

Migra, Robert P.

1987-01-01

The advanced solar dynamic system (ASDS) program is aimed at developing the technology for highly efficient, lightweight space power systems. The approach is to evaluate Stirling, Brayton and liquid metal Rankine power conversion systems (PCS) over the temperature range of 1025 to 1400K, identify the critical technologies and develop these technologies. Microgravity fluid management technology is required in several areas of this program, namely, thermal energy storage (TES), heat pipe applications and liquid metal, two phase flow Rankine systems. Utilization of the heat of fusion of phase change materials offers potential for smaller, lighter TES systems. The candidate TES materials exhibit large volume change with the phase change. The heat pipe is an energy dense heat transfer device. A high temperature application may transfer heat from the solar receiver to the PCS working fluid and/or TES. A low temperature application may transfer waste heat from the PCS to the radiator. The liquid metal Rankine PCS requires management of the boiling/condensing process typical of two phase flow systems.

Comparative evaluation of three alternative power cycles for waste heat recovery from the exhaust of adiabatic diesel engines

NASA Technical Reports Server (NTRS)

Bailey, M. M.

1985-01-01

Three alternative power cycles were compared in application as an exhaust-gas heat-recovery system for use with advanced adiabatic diesel engines. The power cycle alternatives considered were steam Rankine, organic Rankine with RC-1 as the working fluid, and variations of an air Brayton cycle. The comparison was made in terms of fuel economy and economic payback potential for heavy-duty trucks operating in line-haul service. The results indicate that, in terms of engine rated specific fuel consumption, a diesel/alternative-power-cycle engine offers a significant improvement over the turbocompound diesel used as the baseline for comparison. The maximum imporvement resulted from the use of a Rankine cycle heat-recovery system in series with turbocompounding. The air Brayton cycle alternatives studied, which included both simple-cycle and compression-intercooled configurations, were less effective and provided about half the fuel consumption improvement of the Rankine cycle alternatives under the same conditions. Capital and maintenance cost estimates were also developed for each of the heat-recovery power cycle systems. These costs were integrated with the fuel savings to identify the time required for net annual savings to pay back the initial capital investment. The sensitivity of capital payback time to arbitrary increases in fuel price, not accompanied by corresponding hardware cost inflation, was also examined. The results indicate that a fuel price increase is required for the alternative power cycles to pay back capital within an acceptable time period.

Analysis of the Properties of Working Substances for the Organic Rankine Cycle based Database "REFPROP"

NASA Astrophysics Data System (ADS)

Galashov, Nikolay; Tsibulskiy, Svyatoslav; Serova, Tatiana

2016-02-01

The object of the study are substances that are used as a working fluid in systems operating on the basis of an organic Rankine cycle. The purpose of research is to find substances with the best thermodynamic, thermal and environmental properties. Research conducted on the basis of the analysis of thermodynamic and thermal properties of substances from the base "REFPROP" and with the help of numerical simulation of combined-cycle plant utilization triple cycle, where the lower cycle is an organic Rankine cycle. Base "REFPROP" describes and allows to calculate the thermodynamic and thermophysical parameters of most of the main substances used in production processes. On the basis of scientific publications on the use of working fluids in an organic Rankine cycle analysis were selected ozone-friendly low-boiling substances: ammonia, butane, pentane and Freon: R134a, R152a, R236fa and R245fa. For these substances have been identified and tabulated molecular weight, temperature of the triple point, boiling point, at atmospheric pressure, the parameters of the critical point, the value of the derivative of the temperature on the entropy of the saturated vapor line and the potential ozone depletion and global warming. It was also identified and tabulated thermodynamic and thermophysical parameters of the steam and liquid substances in a state of saturation at a temperature of 15 °C. This temperature is adopted as the minimum temperature of heat removal in the Rankine cycle when working on the water. Studies have shown that the best thermodynamic, thermal and environmental properties of the considered substances are pentane, butane and R245fa. For a more thorough analysis based on a gas turbine plant NK-36ST it has developed a mathematical model of combined cycle gas turbine (CCGT) triple cycle, where the lower cycle is an organic Rankine cycle, and is used as the air cooler condenser. Air condenser allows stating material at a temperature below 0 °C. Calculation of the parameters of all substances in the model are based on a base "REFPROP". Numerical investigations on this model showed that the highest net efficiency will be at work on pentane. Butane and R245fa have the same net efficiency, for 0.8% lower than pentane. Ammonia has a net efficiency of 2.5% is lower than pentane. CCP net efficiency strongly depends on the condensation temperature of the substance, as for pentane at lower temperature of condensation at 10 °C it is increased by 1%.

Estimate of Shock-Hugoniot Adiabat of Liquids from Hydrodynamics

NASA Astrophysics Data System (ADS)

Bouton, E.; Vidal, P.

2007-12-01

Shock states are generally obtained from shock velocity (D) and material velocity (u) measurements. In this paper, we propose a hydrodynamical method for estimating the (D-u) relation of Nitromethane from easily measured properties of the initial state. The method is based upon the differentiation of the Rankine-Hugoniot jump relations with the initial temperature considered as a variable and under the constraint of a unique nondimensional shock-Hugoniot. We then obtain an ordinary differential equation for the shock velocity D in the variable u. Upon integration, this method predicts the shock Hugoniot of liquid Nitromethane with a 5% accuracy for initial temperatures ranging from 250 K to 360 K.

The 15 kW sub e (nominal) solar thermal electric power conversion concept definition study: Steam Rankine turbine system

NASA Technical Reports Server (NTRS)

Bland, T. J.

1979-01-01

A study to define the performance and cost characteristics of a solar powered, steam Rankine turbine system located at the focal point of a solar concentrator is presented. A two stage re-entry turbine with reheat between stages, which has an efficiency of 27% at a turbine inlet temperature of 732 C was used. System efficiency was defined as 60 Hertz electrical output divided by absorbed thermal input in the working fluid. Mass production costs were found to be approximately 364 dollars/KW.

Thermal energy storage for organic Rankine cycle solar dynamic space power systems

NASA Astrophysics Data System (ADS)

Heidenreich, G. R.; Parekh, M. B.

An organic Rankine cycle-solar dynamic power system (ORC-SDPS) comprises a concentrator, a radiator, a power conversion unit, and a receiver with a thermal energy storage (TES) subsystem which charges and discharges energy to meet power demands during orbital insolation and eclipse periods. Attention is presently given to the criteria used in designing and evaluating an ORC-SDPS TES, as well as the automated test facility employed. It is found that a substantial data base exists for the design of an ORC-SDPS TES subsystem.

Evaluation of Rankine cycle air conditioning system hardware by computer simulation

NASA Technical Reports Server (NTRS)

Healey, H. M.; Clark, D.

1978-01-01

A computer program for simulating the performance of a variety of solar powered Rankine cycle air conditioning system components (RCACS) has been developed. The computer program models actual equipment by developing performance maps from manufacturers data and is capable of simulating off-design operation of the RCACS components. The program designed to be a subroutine of the Marshall Space Flight Center (MSFC) Solar Energy System Analysis Computer Program 'SOLRAD', is a complete package suitable for use by an occasional computer user in developing performance maps of heating, ventilation and air conditioning components.

Preliminary design package for residential heating/cooling system: Rankine air conditioner redesign

NASA Technical Reports Server (NTRS)

1978-01-01

A summary of the preliminary redesign and development of a marketable single family heating and cooling system is presented. The interim design and schedule status of the residential (3-ton) redesign, problem areas and solutions, and the definition of plans for future design and development activities were discussed. The proposed system for a single-family residential heating and cooling system is a single-loop, solar-assisted, hydronic-to-warm-air heating subsystem with solar-assisted domestic water heating and a Rankine-driven expansion air-conditioning subsystem.

Study on Prediction of Underwater Radiated Noise from Propeller Tip Vortex Cavitation

NASA Astrophysics Data System (ADS)

Yamada, Takuyoshi; Sato, Kei; Kawakita, Chiharu; Oshima, Akira

2015-12-01

The method to predict underwater radiated noise from tip vortex cavitation was studied. The growth of a single cavitation bubble in tip vortex was estimated by substituting the tip vortex to Rankine combined vortex. The ideal spectrum function for the sound pressure generated by a single cavitation bubble was used, also the empirical factor for the number of collapsed bubbles per unit time was introduced. The estimated noise data were compared with measured ship's ones and it was found out that this method can estimate noise data within 3dB difference.

Study of toluene rotary fluid management device and shear flow condenser performance for a space-based organic Rankine power system

NASA Technical Reports Server (NTRS)

Havens, Vance; Ragaller, Dana

1988-01-01

Management of two-phase fluid and control of the heat transfer process in microgravity is a technical challenge that must be addressed for an orbital Organic Rankine Cycle (ORC) application. A test program was performed in 1-g that satisfactorily demonstrated the two-phase management capability of the rotating fluid management device (RFMD) and shear-flow condenser. Operational tests of the RFMD and shear flow condenser in adverse gravity orientations, confirmed that the centrifugal forces in the RFMD and the shear forces in the condenser were capable of overcoming gravity forces. In a microgravity environment, these same forces would not have to compete against gravity and would therefore be dominant. The specific test program covered the required operating range of the Space Station Solar Dynamic Rankine Cycle power system. Review of the test data verified that: fluid was pumped from the RFMD in all attitudes; subcooled states in the condenser were achieved; condensate was pushed uphill against gravity; and noncondensible gases were swept through the condenser.

An RC-1 organic Rankine bottoming cycle for an adiabatic diesel engine

NASA Technical Reports Server (NTRS)

Dinanno, L. R.; Dibella, F. A.; Koplow, M. D.

1983-01-01

A system analysis and preliminary design were conducted for an organic Rankine-cycle system to bottom the high-temperature waste heat of an adiabatic diesel engine. The bottoming cycle is a compact package that includes a cylindrical air cooled condenser regenerator module and other unique features. The bottoming cycle output is 56 horsepower at design point conditions when compounding the reference 317 horsepower turbocharged diesel engine with a resulting brake specific fuel consumption of 0.268 lb/hp-hr for the compound engine. The bottoming cycle when applied to a turbocompound diesel delivers a compound engine brake specific fuel consumption of 0.258 lb/hp-hr. This system for heavy duty transport applications uses the organic working fluid RC-1, which is a mixture of 60 mole percent pentafluorobenzene and 40 mole percent hexafluorobenzene. The thermal stability of the RC-1 organic fluid was tested in a dynamic fluid test loop that simulates the operation of Rankine-cycle. More than 1600 hours of operation were completed with results showing that the RC-1 is thermally stable up to 900 F.

HF radar transmissions that deviate from great-circle paths: new insight from e-POP RRI

NASA Astrophysics Data System (ADS)

Perry, G. W.; Miller, E. S.; James, H. G.; Howarth, A. D.; St-Maurice, J. P.; Yau, A. W.

2016-12-01

Significant deviations of SuperDARN radar transmissions from their expected great-circle paths have been detected at ionospheric altitudes using the Radio Receiver Instrument (RRI) on the Enhanced Polar Outflow Probe (e-POP). Experiments between SuperDARN Rankin Inlet and e-POP RRI were conducted at similar local times over consecutive days. Customized experiment modes which incorporated the agile frequency switching capabilities of each system were used. The RRI measurements show deviations of radar transmissions from their expected paths by as much as 2 or 3 SuperDARN beam widths, equivalent to 6° - 10° in bearing from Rankin Inlet. The deviations displayed a dependence on the radar carrier frequency and a day-to-day variability, suggesting that the deviations were transient in nature. We will discuss the deviations in the context of 3D ray trace modeling and measurements from the Resolute Bay Incoherent Scatter Radar - North (RISR-N). The latter provided diagnostic information of the ionosphere along the ray path between RRI and Rankin Inlet during the experiments.

A thermodynamic analysis of a solar-powered jet refrigeration system

NASA Technical Reports Server (NTRS)

Lansing, F. L.; Chai, V. W.

1980-01-01

The article describes and analyzes a method of using solar energy to drive a jet refrigeration system. A new technique is presented in the form of a performance nomogram combining the energy and momentum equations to determine the performance characteristics. A numerical example, using water as the working fluid, is given to illustrate the nomogram procedure. The resulting coefficient of performance was found comparable with other refrigeration systems such as the solar-absorption system or the solar-Rankine turbocompressor system.

Materials technology programs in support of a mercury Rankine space power system

NASA Technical Reports Server (NTRS)

Stone, P. L.

1973-01-01

A large portion of the materials technology is summarized that was generated in support of the development of a mercury-rankine space power system (SNAP-8). The primary areas of investigation are: (1) the compatibility of various construction materials with the liquid metals mercury and NaK, (2) the mechanical properties of unalloyed tantalum, and (3) the development of refractory metal/austenitic stainless steel tubing and transition joints. The primary results, conclusions, and state of technology at the completion of this effort for each of these areas are summarized. Results of possible significance to other applications are highlighted.

Toluene stability Space Station Rankine power system

NASA Technical Reports Server (NTRS)

Havens, V. N.; Ragaller, D. R.; Sibert, L.; Miller, D.

1987-01-01

A dynamic test loop is designed to evaluate the thermal stability of an organic Rankine cycle working fluid, toluene, for potential application to the Space Station power conversion unit. Samples of the noncondensible gases and the liquid toluene were taken periodically during the 3410 hour test at 750 F peak temperature. The results obtained from the toluene stability loop verify that toluene degradation will not lead to a loss of performance over the 30-year Space Station mission life requirement. The identity of the degradation products and the low rates of formation were as expected from toluene capsule test data.

Estimate of shock-Hugoniot adiabat of liquids from hydrodyamics

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

Bouton, E.; Vidal, P.

2007-12-12

Shock states are generally obtained from shock velocity (D) and material velocity (u) measurements. In this paper, we propose a hydrodynamical method for estimating the (D-u) relation of Nitromethane from easily measured properties of the initial state. The method is based upon the differentiation of the Rankine-Hugoniot jump relations with the initial temperature considered as a variable and under the constraint of a unique nondimensional shock-Hugoniot. We then obtain an ordinary differential equation for the shock velocity D in the variable u. Upon integration, this method predicts the shock Hugoniot of liquid Nitromethane with a 5% accuracy for initial temperaturesmore » ranging from 250 K to 360 K.« less

Effects of alteplase for acute stroke according to criteria defining the European Union and United States marketing authorizations: Individual-patient-data meta-analysis of randomized trials.

PubMed

Hacke, Werner; Lyden, Patrick; Emberson, Jonathan; Baigent, Colin; Blackwell, Lisa; Albers, Gregory; Bluhmki, Erich; Brott, Thomas; Cohen, Geoffrey; Davis, Stephen M; Donnan, Geoffrey A; Grotta, James C; Howard, George; Kaste, Markku; Koga, Masatoshi; von Kummer, Rüdiger; Lansberg, Maarten G; Lindley, Richard I; Olivot, Jean-Marc; Parsons, Mark; Sandercock, Peter Ag; Toni, Danilo; Toyoda, Kazunori; Wahlgren, Nils; Wardlaw, Joanna M; Whiteley, William N; Del Zoppo, Gregory; Lees, Kennedy R

2018-02-01

Background The recommended maximum age and time window for intravenous alteplase treatment of acute ischemic stroke differs between the Europe Union and United States. Aims We compared the effects of alteplase in cohorts defined by the current Europe Union or United States marketing approval labels, and by hypothetical revisions of the labels that would remove the Europe Union upper age limit or extend the United States treatment time window to 4.5 h. Methods We assessed outcomes in an individual-patient-data meta-analysis of eight randomized trials of intravenous alteplase (0.9 mg/kg) versus control for acute ischemic stroke. Outcomes included: excellent outcome (modified Rankin score 0-1) at 3-6 months, the distribution of modified Rankin score, symptomatic intracerebral hemorrhage, and 90-day mortality. Results Alteplase increased the odds of modified Rankin score 0-1 among 2449/6136 (40%) patients who met the current European Union label and 3491 (57%) patients who met the age-revised label (odds ratio 1.42, 95% CI 1.21-1.68 and 1.43, 1.23-1.65, respectively), but not in those outside the age-revised label (1.06, 0.90-1.26). By 90 days, there was no increased mortality in the current and age-revised cohorts (hazard ratios 0.98, 95% CI 0.76-1.25 and 1.01, 0.86-1.19, respectively) but mortality remained higher outside the age-revised label (1.19, 0.99-1.42). Similarly, alteplase increased the odds of modified Rankin score 0-1 among 1174/6136 (19%) patients who met the current US approval and 3326 (54%) who met a 4.5-h revised approval (odds ratio 1.55, 1.19-2.01 and 1.37, 1.17-1.59, respectively), but not for those outside the 4.5-h revised approval (1.14, 0.97-1.34). By 90 days, no increased mortality remained for the current and 4.5-h revised label cohorts (hazard ratios 0.99, 0.77-1.26 and 1.02, 0.87-1.20, respectively) but mortality remained higher outside the 4.5-h revised approval (1.17, 0.98-1.41). Conclusions An age-revised European Union label or 4.5-h-revised United States label would each increase the number of patients deriving net benefit from alteplase by 90 days after acute ischemic stroke, without excess mortality.

Thrombolytic-Related Asymptomatic Hemorrhagic Transformation Does Not Deteriorate Clinical Outcome: Data from TIMS in China

PubMed Central

Jia, Weihua; Liao, Xiaoling; Pan, Yuesong; Wang, Yilong; Cui, Tao; Zhou, Lichun; Wang, Yongjun

2015-01-01

Objective It has been unclear whether thrombolytic-related asymptomatic hemorrhagic transformation (AHT) affects the clinical outcome. To answer this question, we examined whether thrombolytic-related AHT affect short-term and long-term clinical outcome. Methods All data were collected from the Thrombolysis Implementation and Monitor of Acute Ischemic Stroke in China (TIMS-China) registry. The patients were diagnosed as having AHT group and non- hemorrhagic transformation (HT) group based on clinical and imaging data. The patients with symptomatic hemorrhagic transformation were excluded from this study. Thrombolytic-related AHT was defined according to European-Australasian Acute Stroke Study (ECASS) II criteria. 90-day functional outcome, 7-day National Institutes of Health Stroke Scale (NIHSS) score, 7-day and 90-day mortalities were compared between two groups. Logistic regression analysis was used to evaluate the effects of AHT on a short-term and long-term clinical outcome. Results 904 of all 1440 patients in TIMS-China registry were enrolled. 89 (9.6%) patients presented with AHT after thrombolysis within 24-36h. These patients with AHT were more likely to be elder age, cardioembolic subtype, and to have higher National Institutes of Health Stroke Scale score before thrombolysis than patients without AHT. No significant difference was found on the odds of 7-day (95% CI:0.692 (0.218–2.195), (P = 0.532) or 90-day mortalities (95% CI:0.548 (0.237–1.268), P = 0.160) and modified Rankin Score(0–1) at 90-day (95% CI:0.798 (0.460–1.386), P = 0.423) or modified Rankin Score(0–2) at 90-day (95% CI:0.732 (0.429–1.253), P = 0.116) or modified Rankin Score(5–6) at 90-day (95% CI:0.375 (0.169–1.830), P = 0.116) between two groups. Conclusions Thrombolytic-related AHT does not deteriorate short-term and long-term clinical outcome. PMID:26619008

Low body temperature does not compromise the treatment effect of alteplase.

PubMed

Lees, Jennifer S; Mishra, Nishant K; Saini, Monica; Lyden, Patrick D; Shuaib, Ashfaq

2011-09-01

Hypothermia is neuroprotective in ischemic stroke models. The influence of baseline body temperature on outcomes after thrombolytic therapy is unclear. We examined outcomes after alteplase treatment across baseline body temperature for patients with ischemic stroke in data held within the Virtual International Stroke Trials Archive (VISTA; 1998 to 2007). We collated data on age, baseline severity (National Institutes of Health Stroke Scale), and 90-day modified Rankin Scale score on patients presenting with acute ischemic stroke. We compared 90-day modified Rankin Scale score between thrombolyzed and nonthrombolyzed comparators across baseline body temperature. We report age and baseline National Institutes of Health Stroke Scale-adjusted Cochran-Mantel-Haenszel probability value and proportional OR with 95% CI for improved modified Rankin Scale distribution. We report temperature profiles over 72 hours after stroke by treatment group. Rankin data were available for 5586 patients with acute ischemic stroke in VISTA (1980 received alteplase). Age and baseline severity were similar (age 68.0±13.0 years versus 69.9±12.3 years, National Institutes of Health Stroke Scale 14.2±5.2 versus 13.0±5.6). Alteplase was associated with improved outcome (OR, 1.49; 95% CI, 1.35 to 1.65, P<0.0001). Alteplase treatment effect was not associated with baseline temperature (P=0.14). Point estimates showed benefit of alteplase treatment across 35.5°C to 37.5°C but showed a negative trend >37.5°C. Alteplase did not influence temperature profiles over 72 hours after stroke. There is no evidence of influence of body temperature on alteplase treatment response. These results are reassuring that low temperatures across a physiological range do not compromise therapeutic effect of alteplase.

Analysis of heat recovery of diesel engine using intermediate working fluid

NASA Astrophysics Data System (ADS)

Jin, Lei; Zhang, Jiang; Tan, Gangfeng; Liu, Huaming

2017-07-01

The organic Rankine cycle (ORC) is an effective way to recovery the engine exhaust heat. The thermal stability of the evaporation system is significant for the stable operation of the ORC system. In this paper, the performance of the designed evaporation system which combines with the intermediate fluid for recovering the exhaust waste heat from a diesel engine is evaluated. The thermal characteristics of the target diesel engine exhaust gas are evaluated based on the experimental data firstly. Then, the mathematical model of the evaporation system is built based on the geometrical parameters and the specific working conditions of ORC. Finally, the heat transfer characteristics of the evaporation system are estimated corresponding to three typical operating conditions of the diesel engine. The result shows that the exhaust temperature at the evaporator outlet increases slightly with the engine speed and load. In the evaporator, the heat transfer coefficient of the Rankine working fluid is slightly larger than the intermediate fluid. However, the heat transfer coefficient of the intermediate fluid in the heat exchanger is larger than the exhaust side. The heat transfer areas of the evaporator in both the two-phase zone and the preheated zone change slightly along with the engine working condition while the heat transfer areas of the overheated zone has changed obviously. The maximum heat transfer rate occurs in the preheating zone while the minimum value occurs in the overheating zone. In addition, the Rankine working fluid temperature at the evaporator outlet is not sensitively affected by the torque and speed of the engine and the organic fluid flow is relatively stable. It is concluded that the intermediate fluid could effectively reduce the physical changes of Rankine working fluid in the evaporator outlet due to changes in engine operating conditions.

Method and System for Weakening Shock Wave Strength at Leading Edge Surfaces of Vehicle in Supersonic Atmospheric Flight

NASA Technical Reports Server (NTRS)

Pritchett, Victor E., II (Inventor); Wang, Ten-See (Inventor); Blankson, Isaiah M. (Inventor); Daso, Endwell O. (Inventor); Farr, Rebecca Ann (Inventor); Auslender, Aaron Howard (Inventor); Plotkin, Kenneth J. (Inventor)

2015-01-01

A method and system are provided to weaken shock wave strength at leading edge surfaces of a vehicle in atmospheric flight. One or more flight-related attribute sensed along a vehicle's outer mold line are used to control the injection of a non-heated, non-plasma-producing gas into a local external flowfield of the vehicle from at least one leading-edge surface location along the vehicle's outer mold line. Pressure and/or mass flow rate of the gas so-injected is adjusted in order to cause a Rankine-Hugoniot Jump Condition along the vehicle's outer mold line to be violated.

Fixed solar concentrator-collector-satelite receiver and co-generator

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

Meckler, M.

1985-01-01

An insolation and micro wave receiver fixedly installed in alignment with the suns azimuth and within the look angle of a satellite, and comprised of holographic windows recorded according to time related to the suns position as zone plates to concentrate infrared light into a Rankine cycle power generating receiver and to columnate ultraviolet light onto a photo voltaic power generating plane, utilizing a micro wave dish as the substrate support of photo voltaic cells and as a condenser of the Rankine cycle operating an induction generator synchronous with an external alternating current power system, and with the photo voltaicmore » power synchronized therewith by commutation.« less

Technical and economic evaluation of a Brayton-Rankine combined cycle solar-thermal power plant

NASA Astrophysics Data System (ADS)

Wright, J. D.; Copeland, R. J.

1981-05-01

An assessment of gas-liquid direct-contact heat exchange and of a new storage-coupled system was conducted. Both technical and economic issues are evaluated. Specifically, the storage-coupled combined cycle is compared with a molten salt system. The open Brayton cycle system is used as a topping cycle, and the reject heat powers the molten salt/Rankine system. In this study the molten salt system is left unmodified, the Brayton cycle is integrated on top of a Marietta description of an existing molten salt plant. This compares a nonoptimized combined cycle with an optimized molten salt system.

Development of a thermal storage module using modified anhydrous sodium hydroxide

NASA Technical Reports Server (NTRS)

Rice, R. E.; Rowny, P. E.

1980-01-01

The laboratory scale testing of a modified anhydrous NaOH latent heat storage concept for small solar thermal power systems such as total energy systems utilizing organic Rankine systems is discussed. A diagnostic test on the thermal energy storage module and an investigation of alternative heat transfer fluids and heat exchange concepts are specifically addressed. A previously developed computer simulation model is modified to predict the performance of the module in a solar total energy system environment. In addition, the computer model is expanded to investigate parametrically the incorporation of a second heat exchange inside the module which will vaporize and superheat the Rankine cycle power fluid.

Experimental investigation on the effects of swirling flow on augmentor performance

NASA Astrophysics Data System (ADS)

Tan, Haoyuan; Huang, Xianjian

1991-06-01

This paper describes an investigation on the effect of centrifugal force distributions on swirl augmentor performance. The experiments were conducted on the flow drag, temperature-distribution efficiency in the swirl augmentor model with different tangential velocity profiles. Four tangential velocity distributions considered are the Rankine vortex, forced vortex, free vortex, and the constant-angle vortex. The results show that the flow drag of the Rankine vortex swirler is the smallest one, and, in a swirl augmentor where flame is stabilized by using centrifugal force, the combustion efficiency can reach 90 percent or over, though the swirl number is low (S = 0.25).

Advanced Rankine and Brayton cycle power systems - Materials needs and opportunities

NASA Technical Reports Server (NTRS)

Grisaffe, S. J.; Guentert, D. C.

1974-01-01

Conceptual advanced potassium Rankine and closed Brayton power conversion cycles offer the potential for improved efficiency over steam systems through higher operating temperatures. However, for utility service of at least 100,000 hours, materials technology advances will be needed for such high temperature systems. Improved alloys and surface protection must be developed and demonstrated to resist coal combustion gases as well as potassium corrosion or helium surface degradation at high temperatures. Extensions in fabrication technology are necessary to produce large components of high temperature alloys. Long-time property data must be obtained under environments of interest to assure high component reliability.

Advanced Rankine and Brayton cycle power systems: Materials needs and opportunities

NASA Technical Reports Server (NTRS)

Grisaffe, S. J.; Guentert, D. C.

1974-01-01

Conceptual advanced potassium Rankine and closed Brayton power conversion cycles offer the potential for improved efficiency over steam systems through higher operating temperatures. However, for utility service of at least 100,000 hours, materials technology advances will be needed for such high temperature systems. Improved alloys and surface protection must be developed and demonstrated to resist coal combustion gases as well as potassium corrosion or helium surface degradation at high temperatures. Extensions in fabrication technology are necessary to produce large components of high temperature alloys. Long time property data must be obtained under environments of interest to assure high component reliability.

Solar thermal organic rankine cycle for micro-generation

NASA Astrophysics Data System (ADS)

Alkahli, N. A.; Abdullah, H.; Darus, A. N.; Jalaludin, A. F.

2012-06-01

The conceptual design of an Organic Rankine Cycle (ORC) driven by solar thermal energy is developed for the decentralized production of electricity of up to 50 kW. Conventional Rankine Cycle uses water as the working fluid whereas ORC uses organic compound as the working fluid and it is particularly suitable for low temperature applications. The ORC and the solar collector will be sized according to the solar flux distribution in the Republic of Yemen for the required power output of 50 kW. This will be a micro power generation system that consists of two cycles, the solar thermal cycle that harness solar energy and the power cycle, which is the ORC that generates electricity. As for the solar thermal cycle, heat transfer fluid (HTF) circulates the cycle while absorbing thermal energy from the sun through a parabolic trough collector and then storing it in a thermal storage to increase system efficiency and maintains system operation during low radiation. The heat is then transferred to the organic fluid in the ORC via a heat exchanger. The organic fluids to be used and analyzed in the ORC are hydrocarbons R600a and R290.

Preliminary thermodynamic study for an efficient turbo-blower external combustion Rankine cycle

NASA Astrophysics Data System (ADS)

Romero Gómez, Manuel; Romero Gómez, Javier; Ferreiro Garcia, Ramón; Baaliña Insua, Álvaro

2014-08-01

This research paper presents a preliminary thermodynamic study of an innovative power plant operating under a Rankine cycle fed by an external combustion system with turbo-blower (TB). The power plant comprises an external combustion system for natural gas, where the combustion gases yield their thermal energy, through a heat exchanger, to a carbon dioxide Rankine cycle operating under supercritical conditions and with quasi-critical condensation. The TB exploits the energy from the pressurised exhaust gases for compressing the combustion air. The study is focused on the comparison of the combustion system's conventional technology with that of the proposed. An energy analysis is carried out and the effect of the flue gas pressure on the efficiency and on the heat transfer in the heat exchanger is studied. The coupling of the TB results in an increase in efficiency and of the convection coefficient of the flue gas with pressure, favouring a reduced volume of the heat exchanger. The proposed innovative system achieves increases in efficiency of around 12 % as well as a decrease in the heat exchanger volume of 3/5 compared with the conventional technology without TB.

Sex-biased dispersal, kin selection and the evolution of sexual conflict.

PubMed

Faria, Gonçalo S; Varela, Susana A M; Gardner, Andy

2015-10-01

There is growing interest in resolving the curious disconnect between the fields of kin selection and sexual selection. Rankin's (2011, J. Evol. Biol. 24, 71-81) theoretical study of the impact of kin selection on the evolution of sexual conflict in viscous populations has been particularly valuable in stimulating empirical research in this area. An important goal of that study was to understand the impact of sex-specific rates of dispersal upon the coevolution of male-harm and female-resistance behaviours. But the fitness functions derived in Rankin's study do not flow from his model's assumptions and, in particular, are not consistent with sex-biased dispersal. Here, we develop new fitness functions that do logically flow from the model's assumptions, to determine the impact of sex-specific patterns of dispersal on the evolution of sexual conflict. Although Rankin's study suggested that increasing male dispersal always promotes the evolution of male harm and that increasing female dispersal always inhibits the evolution of male harm, we find that the opposite can also be true, depending upon parameter values. © 2015 The Authors. Journal of Evolutionary Biology published by John Wiley & Sons Ltd on behalf of European Society for Evolutionary Biology.

SP-100 multimegawatt scaleup to meet electric propulsion mission requirements

NASA Astrophysics Data System (ADS)

Newkirk, D. W.; Salamah, S. A.; Stewart, S. L.; Pluta, P. R.

The SP-100 nuclear heat source technology, utilizing uranium nitride fuel clad in PWC-11 in a fast reactor with lithium coolant circulated by an electromagnetic pump, is shown to be directly extrapolatable to thermal power levels that meet NASA nuclear electric propulsion requirements using different power conversion techniques. The SP-100 nuclear technology can be applied to missions with NEP (nuclear electric propulsion) requirements as low as tens of kWe to tens of MWe. It is pointed out that the SP-100 heat source has a great advantage of very long lifetime capability, since it utilizes very rugged refractory metal fuel pins and is independent of the power conversion scheme chosen for a given mission. The only moving parts in the nuclear subsystems are the control rods moved to compensate for fuel enrichment degradation due to fission and for power shutdown. Lowest alpha values in the range of interest for potential NASA missions are predicted for the dynamic Rankine and static HYTEC conversion systems.

Measurements and Correlations of cis-1,3,3,3-Tetrafluoroprop-1-ene (R1234ze(Z)) Saturation Pressure

NASA Astrophysics Data System (ADS)

Fedele, Laura; Di Nicola, Giovanni; Brown, J. Steven; Bobbo, Sergio; Zilio, Claudio

2014-01-01

cis-1,3,3,3-Tetrafluoroprop-1-ene (R1234ze(Z)) is being investigated as a working fluid possessing a low global warming potential (GWP) for high-temperature heat pumping applications, organic Rankine cycles, and air-conditioning and refrigeration applications, and as a potential solvent, propellant, and foam blowing agent. Its GWP is less than one. The open literature contains a total of 79 vapor-pressure data from three sources and the critical state properties from a single source. The current paper provides 64 vapor-pressure data from two different laboratories over the temperature range from 238.13 K to 372.61 K. These data are regressed using Wagner and extended Antoine vapor-pressure correlations and then compared to the existing open literature data and correlations. The normal-boiling-point temperature and acentric factor for R1234ze(Z) are estimated to be 282.73 K and 0.3257, respectively.

Fantasies About Stem Cell Therapy in Chronic Ischemic Stroke Patients

PubMed Central

Kim, Young Seo; Chung, Dan-il; Choi, Hojin; Baek, Wonki; Kim, Hyun Young; Heo, Sung Hyuk; Chang, Dae-Il; Na, Hae Ri; Kim, Seung Hyun

2013-01-01

Stem cell therapy (SCT) has been proposed for the treatment of neurological disorders. Although there is insufficient clinical evidence to support its efficacy, unproven SCTs are being performed worldwide. In this study, we investigated the perspectives and expectations of chronic ischemic stroke patients and physicians about SCTs. A total of 250 chronic ischemic stroke patients were interviewed at 4 hospitals. Structured open and closed questions about SCT for chronic stroke were asked by trained interviewers using the conventional in-person method. In addition, 250 stroke-related physicians were randomly interviewed via an e-mail questionnaire. Of the 250 patients (mean 63 years, 70% male), 121 (46%) responded that they wanted to receive SCT in spite of its unknown side effects. Around 60% of the patients anticipated physical, emotional, and psychological improvement after SCT, and 158 (63%) believed that SCT might prevent strokes. However, physicians had much lower expectations about the effectiveness of SCTs, which was not in line with patient expectations. Multivariate analysis revealed that the male gender [odds ratio (OR): 2.00, 95% confidence interval (CI): 1.10–3.64], longer disease duration (OR: 1.01, 95% CI: 1.00–1.02), higher modified Rankin Scale score (OR: 1.30, 95% CI: 1.06–1.60), and familiarity with stem cells (OR: 1.86, 95% CI: 1.10–3.15) were independently associated with wanting SCT. The major source of information about SCT was television (68%), and the most reliable source was physicians (49%). Patients have unfounded expectations that SCT will improve their functioning. Considering our finding that the major source of information on stem cells is media channels, but not the physician, to decrease patients' inappropriate exposure, doctors should make more effort to educate patients using mass media with accurate information. PMID:22784218

To the theory of particle lifting by terrestrial and Martian dust devils

NASA Astrophysics Data System (ADS)

Kurgansky, M. V.

2018-01-01

The combined Rankine vortex model is applied to describe the radial profile of azimuthal velocity in atmospheric dust devils, and a simplified model version is proposed of the turbulent surface boundary layer beneath the Rankine vortex periphery that corresponds to the potential vortex. Based on the results by Burggraf et al. (1971), it is accepted that the radial velocity near the ground in the potential vortex greatly exceeds the azimuthal velocity, which makes tractable the problem of the surface shear stress determination, including the case of the turbulent surface boundary layer. The constructed model explains exceeding the threshold shear velocity for aeolian transport in typical dust-devil vortices both on Earth and on Mars.

The Curious Events Leading to the Theory of Shock Waves

NASA Technical Reports Server (NTRS)

Salas, Manuel D.

2006-01-01

We review the history of the development of the modern theory of shock waves. Several attempts at an early-theory quickly collapsed for lack of foundations in mathematics and thermodynamics. It is not until the works of Rankine and later Hugoniot that a full theory is established. Rankine is the first to show that within the shock a non-adiabatic process must occur. Hugoniot showed that in the absence of viscosity and heat conduction conservation of energy implies conservation of entropy in smooth regions and a jump in entropy across a shock. Even after the theory is fully developed, old notions continue to pervade the literature well into the early part of the 20th Century.

A potassium Rankine multimegawatt nuclear electric propulsion concept

NASA Technical Reports Server (NTRS)

Baumeister, E.; Rovang, R.; Mills, J.; Sercel, J.; Frisbee, R.

1990-01-01

Multimegawatt nuclear electric propulsion (NEP) has been identified as a potentially attractive option for future space exploratory missions. A liquid-metal-cooled reactor, potassium Rankine power system that is being developed is suited to fulfill this application. The key features of the nuclear power system are described, and system characteristics are provided for various potential NEP power ranges and operational lifetimes. The results of recent mission studies are presented to illustrate some of the potential benefits to future space exploration to be gained from high-power NEP. Specifically, mission analyses have been performed to assess the mass and trip time performance of advanced NEP for both cargo and piloted missions to Mars.

Development of an Organic Rankine-Cycle power module for a small community solar thermal power experiment

NASA Technical Reports Server (NTRS)

Kiceniuk, T.

1985-01-01

An organic Rankine-cycle (ORC) power module was developed for use in a multimodule solar power plant to be built and operated in a small community. Many successful components and subsystems, including the reciever, power conversion subsystem, energy transport subsystem, and control subsystem, were tested. Tests were performed on a complete power module using a test bed concentrator in place of the proposed concentrator. All major single-module program functional objectives were met and the multimodule operation presented no apparent problems. The hermetically sealed, self-contained, ORC power conversion unit subsequently successfully completed a 300-hour endurance run with no evidence of wear or operating problems.

Rankine cycle load limiting through use of a recuperator bypass

DOEpatents

Ernst, Timothy C.

2011-08-16

A system for converting heat from an engine into work includes a boiler coupled to a heat source for transferring heat to a working fluid, a turbine that transforms the heat into work, a condenser that transforms the working fluid into liquid, a recuperator with one flow path that routes working fluid from the turbine to the condenser, and another flow path that routes liquid working fluid from the condenser to the boiler, the recuperator being configured to transfer heat to the liquid working fluid, and a bypass valve in parallel with the second flow path. The bypass valve is movable between a closed position, permitting flow through the second flow path and an opened position, under high engine load conditions, bypassing the second flow path.

Analysis of closed cycle megawatt class space power systems with nuclear reactor heat sources

NASA Technical Reports Server (NTRS)

Juhasz, A. J.; Jones, B. I.

1987-01-01

The analysis and integration studies of multimegawatt nuclear power conversion systems for potential SDI applications is presented. A study is summarized which considered 3 separate types of power conversion systems for steady state power generation with a duty requirement of 1 yr at full power. The systems considered are based on the following conversion cycles: direct and indirect Brayton gas turbine, direct and indirect liquid metal Rankine, and in core thermionic. A complete mass analysis was performed for each system at power levels ranging from 1 to 25 MWe for both heat pipe and liquid droplet radiator options. In the modeling of common subsystems, reactor and shield calculations were based on multiparameter correlation and an in-house analysis for the heat rejection and other subsystems.

Stroke Location Is an Independent Predictor of Cognitive Outcome.

PubMed

Munsch, Fanny; Sagnier, Sharmila; Asselineau, Julien; Bigourdan, Antoine; Guttmann, Charles R; Debruxelles, Sabrina; Poli, Mathilde; Renou, Pauline; Perez, Paul; Dousset, Vincent; Sibon, Igor; Tourdias, Thomas

2016-01-01

On top of functional outcome, accurate prediction of cognitive outcome for stroke patients is an unmet need with major implications for clinical management. We investigated whether stroke location may contribute independent prognostic value to multifactorial predictive models of functional and cognitive outcomes. Four hundred twenty-eight consecutive patients with ischemic stroke were prospectively assessed with magnetic resonance imaging at 24 to 72 hours and at 3 months for functional outcome using the modified Rankin Scale and cognitive outcome using the Montreal Cognitive Assessment (MoCA). Statistical maps of functional and cognitive eloquent regions were derived from the first 215 patients (development sample) using voxel-based lesion-symptom mapping. We used multivariate logistic regression models to study the influence of stroke location (number of eloquent voxels from voxel-based lesion-symptom mapping maps), age, initial National Institutes of Health Stroke Scale and stroke volume on modified Rankin Scale and MoCA. The second part of our cohort was used as an independent replication sample. In univariate analyses, stroke location, age, initial National Institutes of Health Stroke Scale, and stroke volume were all predictive of poor modified Rankin Scale and MoCA. In multivariable analyses, stroke location remained the strongest independent predictor of MoCA and significantly improved the prediction compared with using only age, initial National Institutes of Health Stroke Scale, and stroke volume (area under the curve increased from 0.697-0.771; difference=0.073; 95% confidence interval, 0.008-0.155). In contrast, stroke location did not persist as independent predictor of modified Rankin Scale that was mainly driven by initial National Institutes of Health Stroke Scale (area under the curve going from 0.840 to 0.835). Similar results were obtained in the replication sample. Stroke location is an independent predictor of cognitive outcome (MoCA) at 3 months post stroke. © 2015 American Heart Association, Inc.

Years of disability-adjusted life gained as a result of thrombolytic therapy for acute ischemic stroke.

PubMed

Hong, Keun-Sik; Saver, Jeffrey L

2010-03-01

Disability-adjusted life year (DALY) metric reflects years of healthy life lost because of living with disability and years of life lost because of premature mortality. Widely used in epidemiological analyses, DALY has not been applied to acute stroke trials. From previous studies, we derived, for each modified Rankin Scale level, disability weights, disability-linked mortality hazard ratios, and age-specific life expectancies. We then analyzed patient level data from the 2 publicly available National Institute of Neurological Disorders and Stroke (NINDS) recombinant tissue plasminogen activator trials. For each subject, we abstracted age, treatment assignment, and 3-month modified Rankin Scale outcome and calculated the DALYs lost resulting from the qualifying stroke. The disability-linked hazard ratios for premature annual mortality for a modified Rankin Scale score of 0 to 5 were 1.53, 1.52, 2.17, 3.18, 4.55, and 6.55, respectively. In the NINDS recombinant tissue plasminogen activator trials, DALYs (mean+/-SE) lost as a result of the qualifying stroke were substantially less with recombinant tissue plasminogen activator than with placebo (4.64+/-0.17 versus 5.91+/-0.21; P<0.0001), a finding that remained robust after adjustment for baseline prognostic factors. When DALYs gained were apportioned to the 29% of patients experiencing any benefit from lytic therapy, each patient gained an average of 4.4 DALYs. DALY analysis showed greater power than dichotomized modified Rankin Scale analysis in discriminating treatment effects overall and in patients >or=70 years of age. For patients who benefit from treatment, <3-hour thrombolytic therapy adds the equivalent of 4.4 years of healthy life, free of disability. The DALY metric provides a continuous scale that increases statistical power, is intuitively understandable, and is applicable to a wide range of conditions and treatments.

A MODEL FOR THE ORIGIN OF HIGH DENSITY IN LOOPTOP X-RAY SOURCES

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

Longcope, D. W.; Guidoni, S. E.

Super-hot (SH) looptop sources, detected in some large solar flares, are compact sources of HXR emission with spectra matching thermal electron populations exceeding 30 MK. High observed emission measure (EM) and inference of electron thermalization within the small source region both provide evidence of high densities at the looptop, typically more than an order of magnitude above ambient. Where some investigators have suggested such density enhancement results from a rapid enhancement in the magnetic field strength, we propose an alternative model, based on Petschek reconnection, whereby looptop plasma is heated and compressed by slow magnetosonic shocks generated self-consistently through fluxmore » retraction following reconnection. Under steady conditions such shocks can enhance density by no more than a factor of four. These steady shock relations (Rankine-Hugoniot relations) turn out to be inapplicable to Petschek's model owing to transient effects of thermal conduction. The actual density enhancement can in fact exceed a factor of 10 over the entire reconnection outflow. An ensemble of flux tubes retracting following reconnection at an ensemble of distinct sites will have a collective EM proportional to the rate of flux tube production. This rate, distinct from the local reconnection rate within a single tube, can be measured separately through flare ribbon motion. Typical flux transfer rates and loop parameters yield EMs comparable to those observed in SH sources.« less

High Risk of Seizures and Epilepsy after Decompressive Hemicraniectomy for Malignant Middle Cerebral Artery Stroke

PubMed Central

Brondani, Rosane; Garcia de Almeida, Andrea; Abrahim Cherubini, Pedro; Mandelli Mota, Suelen; de Alencastro, Luiz Carlos; Antunes, Apio Cláudio Martins; Bianchin Muxfeldt, Marino

2017-01-01

Background Decompressive hemicraniectomy (DHC) is a life-saving procedure for treatment of large malignant middle cerebral artery (MCA) strokes. Post-stroke epilepsy is an additional burden for these patients, but its incidence and the risk factors for its development have been poorly investigated. Objective To report the prevalence and risk factors for post-stroke seizures and post-stroke epilepsy after DHC for treatment of large malignant MCA strokes in a cohort of 36 patients. Methods In a retrospective cohort study of 36 patients we report the timing and incidence of post-stroke epilepsy. We analyzed if age, sex, vascular risk factors, side of ischemia, reperfusion therapy, stroke etiology, extension of stroke, hemorrhagic transformation, ECASS scores, National Institutes of Health Stroke Scale (NIHSS) scores, or modified Rankin scores were risk factors for seizure or epilepsy after DHC for treatment of large MCA strokes. Results The mean patient follow-up time was 1,086 days (SD = 1,172). Out of 36 patients, 9 (25.0%) died before being discharged. After 1 year, a total of 11 patients (30.6%) had died, but 22 (61.1%) of them had a modified Rankin score ≤4. Thirteen patients (36.1%) developed seizures within the first week after stroke. Seizures occurred in 22 (61.1%) of 36 patients (95% CI = 45.17–77.03%). Out of 34 patients who survived the acute period, 19 (55.9%) developed epilepsy after MCA infarcts and DHC (95% CI = 39.21–72.59%). In this study, no significant differences were observed between the patients who developed seizures or epilepsy and those who remained free of seizures or epilepsy regarding age, sex, side of stroke, presence of the clinical risk factors studied, hemorrhagic transformation, time of craniectomy, and Rankin score after 1 year of stroke. Conclusion The incidence of seizures and epilepsy after malignant MCA infarcts submitted to DHC might be very high. Seizure might occur precociously in patients who are not submitted to anticonvulsant prophylaxis. The large stroke volume and the large cortical ischemic area seem to be the main risk factors for seizure or epilepsy development in this subtype of stroke. PMID:28359069

Methods of increasing net work output of organic Rankine cycles for low-grade waste heat recovery with a detailed analysis using a zeotropic working fluid mixture and scroll expander

NASA Astrophysics Data System (ADS)

Woodland, Brandon Jay

An organic Rankine cycle (ORC) is a thermodynamic cycle that is well-suited for waste heat recovery. It is generally employed for waste heat with temperatures in the range of 80 °C -- 300 °C. When the application is strictly to convert waste heat into work, thermal efficiency is not recommended as a key performance metric. In such an application, maximization of the net power output should be the objective rather than maximization of the thermal efficiency. Two alternative cycle configurations that can increase the net power produced from a heat source with a given temperature and flow rate are proposed and analyzed. These cycle configurations are 1) an ORC with two-phase flash expansion and 2) an ORC with a zeotropic working fluid mixture (ZRC). A design-stage ORC model is presented for consistent comparison of multiple ORC configurations. The finite capacity of the heat source and heat sink fluids is a key consideration in this model. Of all working fluids studied for the baseline ORC, R134a and R245fa yield the highest net power output from a given heat source. Results of the design-stage model indicate that the ORC with two-phase flash expansion offers the most improvement over the baseline ORC. However, the level of improvement that could be achieved in practice is highly uncertain due to the requirement of highly efficient two-phase expansion. The ZRC shows improvement over the baseline as long as the condenser fan power requirement is not negligible. At the highest estimated condenser fan power, the ZRC shows the most improvement, while the ORC with flash expansion is no longer beneficial. The ZRC was selected for detailed study because it does not require two-phase expansion. An experimental test rig was used to evaluate baseline ORC performance with R134a and with R245fa. The ZRC was tested on the same rig with a mixture of 62.5% R134a and 37.5% R245fa. The tested expander is a minimally-modified, of-the-shelf automotive scroll compressor. The high performance to cost ratio of this machine lends significant credence to the economic viability of small-scale, low-temperature ORCs. The experimental campaign covered two heat source temperatures, the full range of pump and expander speeds, a full range of heat source and heat sink fluid flow rates, and various charge levels for the three working fluids. This resulted in 366 steady-state measurements. The steady state measurements are used to develop a detailed ORC model. The model is based on multi-fluid performance maps for the pump and expander and a robust moving-boundary heat exchanger model. It is validated against the measured data and predicts the net power output of the tested ORC with a mean absolute percent error of 7.16%. Comparisons made with the detailed model confirm the predictions of the design-stage model. Using a conservative estimate of the condenser fan power, 19.1% improvement of the ZRC over the baseline ORC is indicated for a source temperature of 80 °C. For a 100 °C source temperature, 13.8% improvement is indicated. A key feature of the detailed ORC model is that it calculates the charge inventory of the working fluid in each heat exchanger and line set. Total system charge can also be specified as a model input. The model can represent the total charge well for R134a at low measured charge levels. As the measured charge level increases, the model becomes less accurate. Reasons for the deviation of the model at higher charge are investigated. It is expected that a charge tuning scheme could be employed to improve the accuracy of model-predicted charge.

CT-angiography source images indicate less fatal outcome despite coma of patients in the Basilar Artery International Cooperation Study.

PubMed

Pallesen, Lars P; Khomenko, Andrei; Dzialowski, Imanuel; Barlinn, Jessica; Barlinn, Kristian; Zerna, Charlotte; van der Hoeven, Erik Jrj; Algra, Ale; Kapelle, L Jaap; Michel, Patrik; Bodechtel, Ulf; Demchuk, Andrew M; Schonewille, Wouter; Puetz, Volker

2017-02-01

Background Coma is associated with poor outcome in patients with basilar artery occlusion. Aims We sought to assess whether the posterior circulation Acute Stroke Prognosis Early CT Score and the Pons-Midbrain Index applied to CT angiography source images predict the outcome of comatose patients in the Basilar Artery International Cooperation Study. Methods Basilar Artery International Cooperation Study was a prospective, observational registry of patients with acute basilar artery occlusion with 48 recruiting centers worldwide. We applied posterior circulation Acute Stroke Prognosis Early CT Score and Pons-Midbrain Index to CT angiography source images of Basilar Artery International Cooperation Study patients who presented with coma. We calculated adjusted risk ratios to assess the association of dichotomized posterior circulation Acute Stroke Prognosis Early CT Score (≥8 vs. <8) and Pons-Midbrain Index (<3 vs. ≥3) with mortality and favourable outcome (modified Rankin Scale score 0-3) at one month. Results Of 619 patients in the Basilar Artery International Cooperation Study registry, CT angiography source images were available for review in 158 patients. Among these, 78 patients (49%) presented with coma. Compared to non-comatose patients, comatose patients were more likely to die (risk ratios 2.34; CI 95% 1.56-3.52) and less likely to have a favourable outcome (risk ratios 0.44; CI 95% 0.24-0.80). Among comatose patients, a Pons-Midbrain Index < 3 was related to reduced mortality (adjusted RR 0.66; 95% CI 0.46-0.96), but not to favourable outcome (adjusted RR 1.19; 95% CI 0.39-3.62). Posterior circulation Acute Stroke Prognosis Early CT Score dichotomized at ≥ 8 vs. <8 was not significantly associated with death (adjusted RR 0.70; 95% CI 0.46-1.05). Conclusion In comatose patients with basilar artery occlusion, the extent of brainstem ischemia appears to be related to mortality but not to favourable outcome.

Characterizing turbulent overturns in CTD-data

NASA Astrophysics Data System (ADS)

van Haren, Hans; Gostiaux, Louis

2014-06-01

We are concerned with the shape of overturns due to irreversible effects of turbulent mixing through internal wave breaking in the ocean. Vertical (z) overturn displacements (d) are computed from ship-borne SeaBird-911 CTD-data using the well-established method of reordering unstable portions in vertical density profiles. When displayed as a function of z, the displacements d(z) reveal a characteristic zigzag shape. Here, we primarily investigate the particular slope (z/d) of this zigzag signature after assigning the displacements to the end-point depths. Using model-overturns we show that this slope equals ½ for a solid-body-rotation, while a more sophisticated Rankine-vortex overturn-model, here employed in the vertical, has slopes slightly >½ in the interior and >1 along the sides. In the case of a near-homogeneous layer, displacement-points fill a parallelogram with side-edges having a slope of 1. The models are used to interpret overturn shapes in NE-Atlantic-Ocean-data from moderately deep, turbulent waters above Rockall Bank (off Ireland) and from deep, weakly stratified waters above Mount Josephine (off Portugal). These are compared with salinity-compensated intrusion data in Mediterranean-outflow-waters in the Canary Basin. Dynamically, most overturns are found to resemble the half-turn Rankine-vortex model and very few a, small-only, solid-body-rotation. Additionally, the usefulness and uselessness of upcast-CTD-data are discussed for overturn characterization.

A Propensity Score Analysis of the Impact of Dexamethasone Use on Delayed Cerebral Ischemia and Poor Functional Outcomes After Subarachnoid Hemorrhage.

PubMed

Mohney, Nathaniel; Williamson, Craig A; Rothman, Edward; Ball, Ron; Sheehan, Kyle M; Pandey, Aditya S; Fletcher, Jeffrey J; Jacobs, Teresa L; Thompson, B Gregory; Rajajee, Venkatakrishna

2018-01-01

An inflammatory response occurs after aneurysmal subarachnoid hemorrhage (aSAH) and predicts poor outcomes. Glucocorticoids suppress inflammation and promote fluid retention. Dexamethasone is often administered after aSAH for postoperative cerebral edema and refractory headache. Our objective was to examine the impact of dexamethasone use on functional outcomes and delayed cerebral ischemia (DCI) after aSAH. Patients with aSAH admitted between 2010 and 2015 were included; the data source was a single-center subarachnoid hemorrhage registry. The intervention of interest was a dexamethasone taper used <7 days from ictus. The primary outcome was poor discharge functional outcome, with a modified Rankin Scale score >3. Other outcomes included DCI and infection. A propensity score for use of dexamethasone was calculated using a logistic regression model that included potential predictors of dexamethasone use and outcome. The impact of dexamethasone on outcomes of interest was calculated and the propensity score was controlled for. A total of 440 patients with subarachnoid hemorrhage were admitted during the study period and 309 met eligibility criteria. Dexamethasone was administered in 101 patients (33%). A total of 127 patients (41%) had a discharge modified Rankin Scale score >3, 105 (34%) developed DCI, and 94 (30%) developed an infection. After propensity score analysis, dexamethasone use was associated with a significant reduction in poor functional outcomes (odds ratio [OR], 0.35; 95% confidence interval [CI], 0.19-0.66) but showed no significant association with DCI (OR, 0.93; 95% CI, 0.53-1.64) or infection (OR, 0.60; 95% CI, 0.34-1.06). Dexamethasone use after aSAH was associated with a reduction in poor functional outcomes at discharge but not DCI, controlling for predictors of dexamethasone use. Copyright © 2017 Elsevier Inc. All rights reserved.

Carbon Management in the Electric Power Industry

NASA Astrophysics Data System (ADS)

Stringer, John

2002-03-01

Approximately 53States in 2000 came from the combustion of coal in Rankine cycle plant; 16principally in Brayton cycle or combined cycle units. Electricity generation is responsible for 36amthropogenic CO2. This compares with 32transportation sector, but since the electric utility generators are large fixed sources it is likely that any legislation designed to reduce CO2 production will adress the utility generators first. Over the last 100 years there has been a continuous decrease in the carbon fraction of the fuels used for energy production world wide, and it is expected that this will continue, principally as a result of the increasing fraction of natural gas. It appears probable that the retirement of the existing nuclear fleet will be delayed by relicensing, and it seems more possible that new nuclear plant will be built than seemed likely even a couple of years ago. The impact of renewables should be increasing, but currently only about 2way currently, and without some considerable incentives, the rate of increase in this component over the next twenty years will probably be small. Currently, hydroelectric plants account for 7indication that this will increase appreciably. At the moment, a significant change would appear to require the capture of CO2 from the exhaust of the combustion plants, and particularly the large existing fleet of coal-fired Rankine units. Following the capture, the CO2 must then be sequestered in secure long-term locations. In addition, increases in the efficiency of power generation, and increases in the efficiency of end use leading to reductions in the energy intensity of the Gross Domestic Product, will be necessary. This paper will review the current state of art in these various approaches to the problem.

Waste Heat-to-Power Using Scroll Expander for Organic Rankine Bottoming Cycle

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

Dieckmann, John; Smutzer, Chad; Sinha, Jayanti

The objective of this program was to develop a novel, scalable scroll expander for conversion of waste heat to power; this was accomplished and demonstrated in both a bench-scale system as well as a full-scale system. The expander is a key component in Organic Rankine Cycle (ORC) waste heat recovery systems which are used to convert medium-grade waste heat to electric power in a wide range of industries. These types of waste heat recovery systems allow for the capture of energy that would otherwise just be exhausted to the atmosphere. A scroll expander has the benefit over other technologies ofmore » having high efficiency over a broad range of operating conditions. The speed range of the TIAX expander (1,200 to 3,600 RPM) enables the shaft power output to directly drive an electric generator and produce 60 Hz electric power without incurring the equipment costs or losses of electronic power conversion. This greatly simplifies integration with the plant electric infrastructure. The TIAX scroll expander will reduce the size, cost, and complexity of a small-scale waste heat recovery system, while increasing the system efficiency compared to the prevailing ORC technologies at similar scale. During this project, TIAX demonstrated the scroll expander in a bench-scale test setup to have isentropic efficiency of 70-75% and operated it successfully for ~200 hours with minimal wear. This same expander was then installed in a complete ORC system driven by a medium grade waste heat source to generate 5-7 kW of electrical power. Due to funding constraints, TIAX was unable to complete this phase of testing, although the initial results were promising and demonstrated the potential of the technology.« less

Performance Analysis of Stirling Engine-Driven Vapor Compression Heat Pump System

NASA Astrophysics Data System (ADS)

Kagawa, Noboru

Stirling engine-driven vapor compression systems have many unique advantages including higher thermal efficiencies, preferable exhaust gas characteristics, multi-fuel usage, and low noise and vibration which can play an important role in alleviating environmental and energy problems. This paper introduces a design method for the systems based on reliable mathematical methods for Stirling and Rankin cycles using reliable thermophysical information for refrigerants. The model deals with a combination of a kinematic Stirling engine and a scroll compressor. Some experimental coefficients are used to formulate the model. The obtained results show the performance behavior in detail. The measured performance of the actual system coincides with the calculated results. Furthermore, the calculated results clarify the performance using alternative refrigerants for R-22.

Use of a turboexpander in steam power units for heat energy recovery in heat supply systems

NASA Astrophysics Data System (ADS)

Sadykov, R. A.; Daminov, A. Z.; Solomin, I. N.; Futin, V. A.

2016-05-01

A method for raising the efficiency of a boiler plant by installing a unit operating by the organic Rankine cycle is presented. Such units allow one to generate electricity to cover the auxiliaries of a heat source at a heat-transfer fluid temperature of no more than 130°C. The results of commissioning tests of boilers revealed that their efficiency is maximized under a load that is close or corresponds to the nominal one. If this load is maintained constantly, excess heat energy is produced. This excess may be used to generate electric energy in a steam power unit with a turboexpander. A way to insert this unit into the flow diagram of a boiler plant is proposed. The results of analysis of turbine types (turboexpanders included) with various capacities are presented, and the optimum type for the proposed flow diagram is chosen. The methodology for the design of turboexpanders and compressors used in the oil and gas industry and their operational data were applied in the analysis of a turboexpander. The results of the thermogasdynamic analysis of a turboexpander and the engineered shape of an axial-radial impeller are presented. Halocarbon R245fa is chosen as the working medium based on its calorimetric properties.

Heat pipe cooled heat rejection subsystem modelling for nuclear electric propulsion

NASA Astrophysics Data System (ADS)

Moriarty, Michael P.

1993-11-01

NASA LeRC is currently developing a FORTRAN based computer model of a complete nuclear electric propulsion (NEP) vehicle that can be used for piloted and cargo missions to the Moon or Mars. Proposed designs feature either a Brayton or a K-Rankine power conversion cycle to drive a turbine coupled with rotary alternators. Both ion and magnetoplasmodynamic (MPD) thrusters will be considered in the model. In support of the NEP model, Rocketdyne is developing power conversion, heat rejection, and power management and distribution (PMAD) subroutines. The subroutines will be incorporated into the NEP vehicle model which will be written by NASA LeRC. The purpose is to document the heat pipe cooled heat rejection subsystem model and its supporting subroutines. The heat pipe cooled heat rejection subsystem model is designed to provide estimate of the mass and performance of the equipment used to reject heat from Brayton and Rankine cycle power conversion systems. The subroutine models the ductwork and heat pipe cooled manifold for a gas cooled Brayton; the heat sink heat exchanger, liquid loop piping, expansion compensator, pump and manifold for a liquid loop cooled Brayton; and a shear flow condenser for a K-Rankine system. In each case, the final heat rejection is made by way of a heat pipe radiator. The radiator is sized to reject the amount of heat necessary.

Survey of solar thermal energy storage subsystems for thermal/electric applications

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

Segaser, C. L.

1978-08-01

A survey of the current technology and estimated costs of subsystems for storing the thermal energy produced by solar collectors is presented. The systems considered were capable of producing both electricity and space conditioning for three types of loads: a single-family detached residence, an apartment complex of 100 units, and a city of 30,000 residents, containing both single-family residences and apartments. Collector temperatures will be in four ranges: (1) 100 to 250/sup 0/F (used for space heating and single-cycle air conditioners and organic Rankine low-temperature turbines); (2) 300 to 400/sup 0/F (used for dual-cycle air conditioners and low-temperature turbines); (3)more » 400 to 600/sup 0/F (using fluids from parabolic trough collectors to run Rankine turbines); (4) 800 to 1000/sup 0/F (using fluids from heliostats to run closed-cycle gas turbines and steam Rankine turbines). The solar thermal energy subsystems will require from 60 to 36 x 10/sup 5/ kWhr (2.05 x 10/sup 5/ to 1.23 x 10/sup 10/ Btu) of thermal storage capacity. In addition to sensible heat and latent heat storage materials, several other media were investigated as potential thermal energy storage materials, including the clathrate and semiclathrate hydrates, various metal hydrides, and heat storage based on inorganic chemical reactions.« less

Steam Rankine Solar Receiver, phase 2

NASA Technical Reports Server (NTRS)

Deanda, L. E.; Faust, M.

1981-01-01

A steam rankine solar receiver (SRSR) based on a tubular concept was designed and developed. The SRSR is an insulated, cylindrical coiled tube boiler which is mounted at the focal plane of a fully tracking parabolic solar reflector. The concentrated solar energy received at the focal plane is then transformed to thermal energy through steam generation. The steam is used in a small Rankine cycle heat engine to drive a generator for the production of electrical energy. The SRSR was designed to have a dual mode capability, performing as a once through boiler with and without reheat. This was achieved by means of two coils which constitute the boiler. The boiler core size of the SRSR is 17.0 inches in diameter and 21.5 inches long. The tube size is 7/16 inch I.D. by 0.070 inch wall for the primary, and 3/4 inch I.D. by 0.125 inch wall for the reheat section. The materials used were corrosion resistant steel (CRES) type 321 and type 347 stainless steel. The core is insulated with 6 inches of cerablanket insulation wrapped around the outer wall. The aperture end and the reflector back plate at the closed end section are made of silicon carbide. The SRSR accepts 85 kwth and has a design life of 10,000 hrs when producing steam at 1400 F and 2550 psig.

Heat pipe cooled heat rejection subsystem modelling for nuclear electric propulsion

NASA Technical Reports Server (NTRS)

Moriarty, Michael P.

1993-01-01

NASA LeRC is currently developing a FORTRAN based computer model of a complete nuclear electric propulsion (NEP) vehicle that can be used for piloted and cargo missions to the Moon or Mars. Proposed designs feature either a Brayton or a K-Rankine power conversion cycle to drive a turbine coupled with rotary alternators. Both ion and magnetoplasmodynamic (MPD) thrusters will be considered in the model. In support of the NEP model, Rocketdyne is developing power conversion, heat rejection, and power management and distribution (PMAD) subroutines. The subroutines will be incorporated into the NEP vehicle model which will be written by NASA LeRC. The purpose is to document the heat pipe cooled heat rejection subsystem model and its supporting subroutines. The heat pipe cooled heat rejection subsystem model is designed to provide estimate of the mass and performance of the equipment used to reject heat from Brayton and Rankine cycle power conversion systems. The subroutine models the ductwork and heat pipe cooled manifold for a gas cooled Brayton; the heat sink heat exchanger, liquid loop piping, expansion compensator, pump and manifold for a liquid loop cooled Brayton; and a shear flow condenser for a K-Rankine system. In each case, the final heat rejection is made by way of a heat pipe radiator. The radiator is sized to reject the amount of heat necessary.

NERVA-Derived Nuclear Thermal Propulsion Dual Mode Operation

NASA Astrophysics Data System (ADS)

Zweig, Herbert R.; Hundal, Rolv

1994-07-01

Generation of electrical power using the nuclear heat source of a NERVA-derived nuclear thermal rocket engine is presented. A 111,200 N thrust engine defined in a study for NASA-LeRC in FY92 is the reference engine for a three-engine vehicle for which a 50 kWe capacity is required. Processes are described for energy extraction from the reactor and for converting the energy to electricity. The tie tubes which support the reactor fuel elements are the source of thermal energy. The study focuses on process systems using Stirling cycle energy conversion operating at 980 K and an alternate potassium-Rankine system operating at 1,140 K. Considerations are given of the effect of the power production on turbopump operation, ZrH moderator dissociation, creep strain in the tie tubes, hydrogen permeation through the containment materials, requirements for a backup battery system, and the effects of potential design changes on reactor size and criticality. Nuclear considerations include changing tie tube materials to TZM, changing the moderator to low vapor-pressure yttrium hydride, and changing the fuel form from graphite matrix to a carbon-carbide composite.

Thermal power systems point-focusing distributed receiver technology project. Volume 1: Executive summary

NASA Technical Reports Server (NTRS)

Lucas, J.

1979-01-01

Thermal or electrical power from the sun's radiated energy through Point-Focusing Distributed Receiver Technology is the goal of this project. The energy thus produced must be technically, as well as economically, competitive with other energy sources. This project is to support the industrial development of the required technology to achieve the above stated goal. Solar energy is concentrated by either a reflecting surface or a lense to a receiver where it is transferred to a working liquid or gas. Receiver temperatures are in the 1000 - 2000 F range. Conceptual design studies are expected to identify power conversion units with a viable place in the solar energy future. Rankine and Brayton cycle engines are under investigation. This report details the Jet Propulsion Laboratory's accomplishments with point-focusing technology in Fy 1978.

Analysis of saccular aneurysms in the Barrow Ruptured Aneurysm Trial.

PubMed

Spetzler, Robert F; Zabramski, Joseph M; McDougall, Cameron G; Albuquerque, Felipe C; Hills, Nancy K; Wallace, Robert C; Nakaji, Peter

2018-01-01

OBJECTIVE The Barrow Ruptured Aneurysm Trial (BRAT) is a prospective, randomized trial in which treatment with clipping was compared to treatment with coil embolization. Patients were randomized to treatment on presentation with any nontraumatic subarachnoid hemorrhage (SAH). Because all other randomized trials comparing these 2 types of treatments have been limited to saccular aneurysms, the authors analyzed the current BRAT data for this subgroup of lesions. METHODS The primary BRAT analysis included all sources of SAH: nonaneurysmal lesions; saccular, blister, fusiform, and dissecting aneurysms; and SAHs from an aneurysm associated with either an arteriovenous malformation or a fistula. In this post hoc review, the outcomes for the subgroup of patients with saccular aneurysms were further analyzed by type of treatment. The extent of aneurysm obliteration was adjudicated by an independent neuroradiologist not involved in treatment. RESULTS Of the 471 patients enrolled in the BRAT, 362 (77%) had an SAH from a saccular aneurysm. Patients with saccular aneurysms were assigned equally to the clipping and the coiling cohorts (181 each). In each cohort, 3 patients died before treatment and 178 were treated. Of the 178 clip-assigned patients with saccular aneurysms, 1 (1%) was crossed over to coiling, and 64 (36%) of the 178 coil-assigned patients were crossed over to clipping. There was no statistically significant difference in poor outcome (modified Rankin Scale score > 2) between these 2 treatment arms at any recorded time point during 6 years of follow-up. After the initial hospitalization, 1 of 241 (0.4%) clipped saccular aneurysms and 21 of 115 (18%) coiled saccular aneurysms required retreatment (p < 0.001). At the 6-year follow-up, 95% (95/100) of the clipped aneurysms were completely obliterated, compared with 40% (16/40) of the coiled aneurysms (p < 0.001). There was no difference in morbidity between the 2 treatment groups (p = 0.10). CONCLUSIONS In the subgroup of patients with saccular aneurysms enrolled in the BRAT, there was no significant difference between modified Rankin Scale outcomes at any follow-up time in patients with saccular aneurysms assigned to clipping compared with those assigned to coiling (intent-to-treat analysis). At the 6-year follow-up evaluation, rates of retreatment and complete aneurysm obliteration significantly favored patients who underwent clipping compared with those who underwent coiling. Clinical trial registration no.: NCT01593267 (clinicaltrials.gov).

Economic Evaluation Plan (EEP) for A Very Early Rehabilitation Trial (AVERT): An international trial to compare the costs and cost-effectiveness of commencing out of bed standing and walking training (very early mobilization) within 24 h of stroke onset with usual stroke unit care.

PubMed

Sheppard, Lauren; Dewey, Helen; Bernhardt, Julie; Collier, Janice M; Ellery, Fiona; Churilov, Leonid; Tay-Teo, Kiu; Wu, Olivia; Moodie, Marj

2016-06-01

A key objective of A Very Early Rehabilitation Trial is to determine if the intervention, very early mobilisation following stroke, is cost-effective. Resource use data were collected to enable an economic evaluation to be undertaken and a plan for the main economic analyses was written prior to the completion of follow up data collection. To report methods used to collect resource use data, pre-specify the main economic evaluation analyses and report other intended exploratory analyses of resource use data. Recruitment to the trial has been completed. A total of 2,104 participants from 56 stroke units across three geographic regions participated in the trial. Resource use data were collected prospectively alongside the trial using standardised tools. The primary economic evaluation method is a cost-effectiveness analysis to compare resource use over 12 months with health outcomes of the intervention measured against a usual care comparator. A cost-utility analysis is also intended. The primary outcome in the cost-effectiveness analysis will be favourable outcome (modified Rankin Scale score 0-2) at 12 months. Cost-utility analysis will use health-related quality of life, reported as quality-adjusted life years gained over a 12 month period, as measured by the modified Rankin Scale and the Assessment of Quality of Life. Outcomes of the economic evaluation analysis will inform the cost-effectiveness of very early mobilisation following stroke when compared to usual care. The exploratory analysis will report patterns of resource use in the first year following stroke. © 2016 World Stroke Organization.

Explicit Consideration of Baseline Factors to Assess Recombinant Tissue-Type Plasminogen Activator Response With Respect to Race and Sex

PubMed Central

Mandava, Pitchaiah; Murthy, Santosh B.; Munoz, Melody; McGuire, Dawn; Simon, Roger P.; Alexandrov, Andrei V.; Albright, Karen C.; Boehme, Amelia K.; Martin-Schild, Sheryl; Martini, Sharyl; Kent, Thomas A.

2017-01-01

Background and Purpose Sex and race reportedly influence outcome after recombinant tissue-type plasminogen activator (rtPA). It is, however, unclear whether baseline imbalances (eg, stroke severity) or lack of response to thrombolysis is responsible. We applied balancing methods to test the hypothesis that race and sex influence outcome after rtPA independent of baseline conditions. Methods We mapped group outcomes from the National Institute of Neurological Disorders and Stroke (NINDS) dataset based on race and sex onto a surrogate-control function to assess differences from expected outcomes at their respective National Institutes of Health Stroke Scale and age. Outcomes were also compared for subjects matched individually on key baseline factors using NINDS and 2 recent datasets from southeastern United States. Results At similar National Institutes of Health Stroke Scale and age, 90-day good outcomes (modified Rankin Score, 0–2) in NINDS were similarly improved after rtPA for white men and women. There was a strong trend for improvement in black men. Conversely, black women treated with rtPA showed response rates no different from the controls. After baseline matching, there were nonsignificant trends in outcomes except for significantly fewer good outcomes in black versus matched white women (37% versus 63%; P=0.027). Pooling the 3 datasets showed a similar trend for poorer short-term outcome for black women (P=0.054; modified Rankin Score, 0–1). Conclusions Matching for key baseline factors indicated that race and sex influence outcome most strikingly in black women who demonstrated poorest outcomes after rtPA. This finding supports the hypothesis that poor response to rtPA, rather than differences in baseline conditions, contributes to the worse outcome. This finding requires prospective confirmation. PMID:23674524

Various continuum approaches for studying shock wave structure in carbon dioxide

NASA Astrophysics Data System (ADS)

Alekseev, I. V.; Kosareva, A. A.; Kustova, E. V.; Nagnibeda, E. A.

2018-05-01

Shock wave structure in carbon dioxide is studied using different continuum models within the framework of one-temperature thermal equilibrium flow description. Navier-Stokes and Euler equations as well as commonly used Rankine-Hugoniot equations with different specific heat ratios are used to find the gas-dynamic parameters behind the shock wave. The accuracy of the Rankine-Hugoniot relations in polyatomic gases is assessed, and it is shown that they give a considerable error in the predicted values of fluid-dynamic variables. The effect of bulk viscosity on the shock wave structure in CO2 is evaluated. Taking into account bulk viscosity yields a significant increase in the shock wave width; for the complete model, the shock wave thickness varies non-monotonically with the Mach number.

Energy comparison between solar thermal power plant and photovoltaic power plant

NASA Astrophysics Data System (ADS)

Novosel, Urška; Avsec, Jurij

2017-07-01

The combined use of renewable energy and alternative energy systems and better efficiency of energy devices is a promising approach to reduce effects due to global warming in the world. On the basis of first and second law of thermodynamics we could optimize the processes in the energy sector. The presented paper shows the comparison between solar thermal power plant and photovoltaic power plant in terms of energy, exergy and life cycle analysis. Solar thermal power plant produces electricity with basic Rankine cycle, using solar tower and solar mirrors to produce high fluid temperature. Heat from the solar system is transferred by using a heat exchanger to Rankine cycle. Both power plants produce hydrogen via electrolysis. The paper shows the global efficiency of the system, regarding production of the energy system.

Multimegawatt potassium Rankine power for nuclear electric power

NASA Technical Reports Server (NTRS)

Rovang, Richard D.; Mills, Joseph C.; Baumeister, Ernie B.

1991-01-01

A cermet fueled potassium rankine power system concept has been developed for various power ranges and operating lifetimes. This concept utilizes a single primary lithium loop to transport thermal energy from the reactor to the boiler. Multiple, independent potassium loops are employed to achieve the required reliability of 99 percent. The potassium loops are two phase systems which expand heated potassium vapor through multistage turboalternators to produce a 10-kV dc electrical output. Condensation occurs by-way-of a shear-flow condenser, producing a 100 percent liquid potassium stream which is pumped back to the boiler. Waste heat is rejected by an advanced carbon-carbon radiator at approximately 1000 K. Overall system efficiencies of 19.3 percent to 20.5 percent were calculated depending on mission life and power level.

Energy Conversion Alternatives Study (ECAS), Westinghouse phase 1. Volume 7: Metal vapor Rankine topping-steam bottoming cycles. [energy conversion efficiency in electric power plants

NASA Technical Reports Server (NTRS)

Deegan, P. B.

1976-01-01

Adding a metal vapor Rankine topper to a steam cycle was studied as a way to increase the mean temperature at which heat is added to the cycle to raise the efficiency of an electric power plant. Potassium and cesium topping fluids were considered. Pressurized fluidized bed or pressurized (with an integrated low-Btu gasifier) boilers were assumed. Included in the cycles was a pressurizing gas turbine with its associated recuperator, and a gas economizer and feedwater heater. One of the ternary systems studied shows plant efficiency of 42.3% with a plant capitalization of $66.7/kW and a cost of electricity of 8.19 mills/MJ (29.5 mills/kWh).

Organic Rankine Cycle for Residual Heat to Power Conversion in Natural Gas Compressor Station. Part I: Modelling and Optimisation Framework

NASA Astrophysics Data System (ADS)

Chaczykowski, Maciej

2016-06-01

Basic organic Rankine cycle (ORC), and two variants of regenerative ORC have been considered for the recovery of exhaust heat from natural gas compressor station. The modelling framework for ORC systems has been presented and the optimisation of the systems was carried out with turbine power output as the variable to be maximized. The determination of ORC system design parameters was accomplished by means of the genetic algorithm. The study was aimed at estimating the thermodynamic potential of different ORC configurations with several working fluids employed. The first part of this paper describes the ORC equipment models which are employed to build a NLP formulation to tackle design problems representative for waste energy recovery on gas turbines driving natural gas pipeline compressors.

A review of test results on parabolic dish solar thermal power modules with dish-mounted Rankine engines and for production of process steam

NASA Technical Reports Server (NTRS)

Jaffe, Leonard D.

1988-01-01

This paper presents results of development testing of various solar thermal parabolic dish modules and assemblies. Most of the tests were at modules and assemblies that used a dish-mounted, organic Rankine cycle turbine for production of electric power. Some tests were also run on equipment for production of process steam or for production of electricity using dish-mounted reciprocating steam engines. These tests indicate that early modules achieve efficiencies of about 18 percent in converting sunlight to electricity (excluding the inverter but including parasitics). A number of malfunctions occurred. The performance measurements, as well as the malfunctions and other operating experience, provided information that should be of value in developing systems with improved performance and reduced maintenance.

Advanced high-temperature electromagnetic pump

NASA Technical Reports Server (NTRS)

Gahan, J. W.; Powell, A. H.

1972-01-01

Three phase helical, electromagnetic induction pump for use as boiler feed pump in potassium Rankine-cycle power system is described. Techniques for fabricating components of pump are discussed. Specifications of pump are analyzed.

Metastasis

MedlinePlus

Doroshow JH. Approach to the patient with cancer. In: Goldman L, Schafer AI, eds. Goldman-Cecil Medicine . 25th ed. Philadelphia, PA: Elsevier Saunders; 2016:chap 179. Rankin EB. Erler J. Giaccia AJ. The cellular microenvironment and ...

Rapid blood-pressure lowering in patients with acute intracerebral hemorrhage.

PubMed

Anderson, Craig S; Heeley, Emma; Huang, Yining; Wang, Jiguang; Stapf, Christian; Delcourt, Candice; Lindley, Richard; Robinson, Thompson; Lavados, Pablo; Neal, Bruce; Hata, Jun; Arima, Hisatomi; Parsons, Mark; Li, Yuechun; Wang, Jinchao; Heritier, Stephane; Li, Qiang; Woodward, Mark; Simes, R John; Davis, Stephen M; Chalmers, John

2013-06-20

Whether rapid lowering of elevated blood pressure would improve the outcome in patients with intracerebral hemorrhage is not known. We randomly assigned 2839 patients who had had a spontaneous intracerebral hemorrhage within the previous 6 hours and who had elevated systolic blood pressure to receive intensive treatment to lower their blood pressure (with a target systolic level of <140 mm Hg within 1 hour) or guideline-recommended treatment (with a target systolic level of <180 mm Hg) with the use of agents of the physician's choosing. The primary outcome was death or major disability, which was defined as a score of 3 to 6 on the modified Rankin scale (in which a score of 0 indicates no symptoms, a score of 5 indicates severe disability, and a score of 6 indicates death) at 90 days. A prespecified ordinal analysis of the modified Rankin score was also performed. The rate of serious adverse events was compared between the two groups. Among the 2794 participants for whom the primary outcome could be determined, 719 of 1382 participants (52.0%) receiving intensive treatment, as compared with 785 of 1412 (55.6%) receiving guideline-recommended treatment, had a primary outcome event (odds ratio with intensive treatment, 0.87; 95% confidence interval [CI], 0.75 to 1.01; P=0.06). The ordinal analysis showed significantly lower modified Rankin scores with intensive treatment (odds ratio for greater disability, 0.87; 95% CI, 0.77 to 1.00; P=0.04). Mortality was 11.9% in the group receiving intensive treatment and 12.0% in the group receiving guideline-recommended treatment. Nonfatal serious adverse events occurred in 23.3% and 23.6% of the patients in the two groups, respectively. In patients with intracerebral hemorrhage, intensive lowering of blood pressure did not result in a significant reduction in the rate of the primary outcome of death or severe disability. An ordinal analysis of modified Rankin scores indicated improved functional outcomes with intensive lowering of blood pressure. (Funded by the National Health and Medical Research Council of Australia; INTERACT2 ClinicalTrials.gov number, NCT00716079.).

Thermal control systems for low-temperature heat rejection on a lunar base

NASA Technical Reports Server (NTRS)

Sridhar, K. R.; Gottmann, Matthias

1992-01-01

In this report, Rankine-cycle heat pumps and absorption heat pumps (ammonia-water and lithium bromide-water) have been analyzed and optimized for a lunar base cooling load of 100 kW. For the Rankine cycle, a search of several commonly used commercial refrigerants provided R11 and R717 as possible working fluids. Hence, the Rankine-cycle analysis has been performed for both R11 and R717. Two different configurations were considered for the system--one in which the heat pump is directly connected to the rejection loop and another in which a heat exchanger connects the heat pump to the rejection loop. For a marginal increase in mass, the decoupling of the rejection loop and the radiator from the heat pump provides greater reliability of the system and better control. Hence, the decoupled system is the configuration of choice. The optimal TCS mass for a 100 kW cooling load at 270 K was 5940 kg at a radiator temperature of 362 K. R11 was the working fluid in the heat pump, and R717 was the transport fluid in the rejection loop. Two TCS's based on an absorption-cycle heat pump were considered, one with an ammonia-water mixture and the other with a lithium bromide-water mixture as the working fluid. A complete cycle analysis was performed for these systems. The system components were approximated as heat exchangers with no internal pressure drop for the mass estimate. This simple approach underpredicts the mass of the systems, but is a good 'optimistic' first approximation to the TCS mass in the absence of reliable component mass data. The mass estimates of the two systems reveal that, in spite of this optimistic estimate, the absorption heat pumps are not competitive with the Rankine-cycle heat pumps. Future work at the systems level will involve similar analyses for the Brayton- and Stirling-cycle heat pumps. The analyses will also consider the operation of the pump under partial-load conditions. On the component level, a capillary evaporator will be designed, built, and tested in order to investigate its suitability in lunar base TCS and microgravity two-phase applications.

Summary and evaluation of the Strategic Defense Initiative Space Power Architecture Study

NASA Technical Reports Server (NTRS)

Edenburn, M. (Editor); Smith, J. M. (Editor)

1989-01-01

The Space Power Architecture Study (SPAS) identified and evaluated power subsystem options for multimegawatt electric (MMWE) space based weapons and surveillance platforms for the Strategic Defense Initiative (SDI) applications. Steady state requirements of less than 1 MMWE are adequately covered by the SP-100 nuclear space power program and hence were not addressed in the SPAS. Four steady state power systems less than 1 MMWE were investigated with little difference between them on a mass basis. The majority of the burst power systems utilized H(2) from the weapons and were either closed (no effluent), open (effluent release) or steady state with storage (no effluent). Closed systems used nuclear or combustion heat source with thermionic, Rankine, turboalternator, fuel cell and battery conversion devices. Open systems included nuclear or combustion heat sources using turboalternator, magnetohydrodynamic, fuel cell or battery power conversion devices. The steady state systems with storage used the SP-100 or Star-M reactors as energy sources and flywheels, fuel cells or batteries to store energy for burst applications. As with other studies the open systems are by far the lightest, most compact and simplist (most reliable) systems. However, unlike other studies the SPAS studied potential platform operational problems caused by effluents or vibration.

Organic Rankine cycle receiver development

NASA Technical Reports Server (NTRS)

Haskins, H. J.

1981-01-01

The selected receiver concept is a direct-heated, once-through, monotube boiler operated at supercritical pressure. The cavity is formed by a cylindrical copper shell and backwall, with stainless steel tubing brazed to the outside surface. This core is surrounded by lightweight refractory insulation, load-bearing struts, and an outer case. The aperture plate is made of copper to provide long life by conduction and reradiation of heat away from the aperture lip. The receiver thermal efficiency is estimated to be 97 percent at rated conditions (energy transferred to toluene divided by energy incident on aperture opening). Development of the core manufacturing and corrosion protection methods is complete.

40 CFR 72.3 - Measurements, abbreviations, and acronyms.

Code of Federal Regulations, 2010 CFR

2010-07-01

.... MWe—megawatt electrical. MWge—gross megawatt electrical. NIST—National Institute of Standards and Technology. ppm—parts per million. psi—pounds per square inch. °R—degree Rankine. RATA—relative accuracy test...

40 CFR 72.3 - Measurements, abbreviations, and acronyms.

Code of Federal Regulations, 2012 CFR

2012-07-01

.... MWe—megawatt electrical. MWge—gross megawatt electrical. NIST—National Institute of Standards and Technology. ppm—parts per million. psi—pounds per square inch. °R—degree Rankine. RATA—relative accuracy test...

40 CFR 72.3 - Measurements, abbreviations, and acronyms.

Code of Federal Regulations, 2014 CFR

2014-07-01

.... MWe—megawatt electrical. MWge—gross megawatt electrical. NIST—National Institute of Standards and Technology. ppm—parts per million. psi—pounds per square inch. °R—degree Rankine. RATA—relative accuracy test...

40 CFR 72.3 - Measurements, abbreviations, and acronyms.

Code of Federal Regulations, 2011 CFR

2011-07-01

.... MWe—megawatt electrical. MWge—gross megawatt electrical. NIST—National Institute of Standards and Technology. ppm—parts per million. psi—pounds per square inch. °R—degree Rankine. RATA—relative accuracy test...

40 CFR 72.3 - Measurements, abbreviations, and acronyms.

Code of Federal Regulations, 2013 CFR

2013-07-01

.... MWe—megawatt electrical. MWge—gross megawatt electrical. NIST—National Institute of Standards and Technology. ppm—parts per million. psi—pounds per square inch. °R—degree Rankine. RATA—relative accuracy test...

Thermodynamic Analysis of Beam down Solar Gas Turbine Power Plant equipped with Concentrating Receiver System

NASA Astrophysics Data System (ADS)

Azharuddin; Santarelli, Massimo

2016-09-01

Thermodynamic analysis of a closed cycle, solar powered Brayton gas turbine power plant with Concentrating Receiver system has been studied. A Brayton cycle is simpler than a Rankine cycle and has an advantage where the water is scarce. With the normal Brayton cycle a Concentrating Receiver System has been analysed which has a dependence on field density and optical system. This study presents a method of optimization of design parameter, such as the receiver working temperature and the heliostats density. This method aims at maximizing the overall efficiency of the three major subsystem that constitute the entire plant, namely, the heliostat field and the tower, the receiver and the power block. The results of the optimization process are shown and analysed.

Comparative performance of twenty-three types of flat plate solar energy collectors

NASA Technical Reports Server (NTRS)

Simon, F. F.

1975-01-01

Report compares efficiencies of 23 solar collectors for four different purposes: operating a Rankine-cycle engine, heating or absorption air conditioning, heating hot water, and heating a swimming pool.

Preliminary design of a supercritical CO2 wind tunnel

NASA Astrophysics Data System (ADS)

Re, B.; Rurale, A.; Spinelli, A.; Guardone, A.

2017-03-01

The preliminary design of a test-rig for non-ideal compressible-fluid flows of carbon dioxide is presented. The test-rig is conceived to investigate supersonic flows that are relevant to the study of non-ideal compressible-fluid flows in the close proximity of the critical point and of the liquid-vapor saturation curve, to the investigation of drop nucleation in compressors operating with supercritical carbon dioxide and and to the study of flow conditions similar to those encountered in turbines for Organic Rankine Cycle applications. Three different configurations are presented and examined: a batch-operating test-rig, a closed-loop Brayton cycle and a closed-loop Rankine cycle. The latter is preferred for its versatility and for economic reasons. A preliminary design of the main components is reported, including the heat exchangers, the chiller, the pumps and the test section.

Rankine engine solar power generation. I - Performance and economic analysis

NASA Technical Reports Server (NTRS)

Gossler, A. A.; Orrock, J. E.

1981-01-01

Results of a computer simulation of the performance of a solar flat plate collector powered electrical generation system are presented. The simulation was configured to include locations in New Mexico, North Dakota, Tennessee, and Massachusetts, and considered a water-based heat-transfer fluid collector system with storage. The collectors also powered a Rankine-cycle boiler filled with a low temperature working fluid. The generator was considered to be run only when excess solar heat and full storage would otherwise require heat purging through the collectors. All power was directed into the utility grid. The solar powered generator unit addition was found to be dependent on site location and collector area, and reduced the effective solar cost with collector areas greater than 400-670 sq m. The sites were economically ranked, best to worst: New Mexico, North Dakota, Massachusetts, and Tennessee.

Treatment Strategies for Intracranial Mirror Aneurysms.

PubMed

Wang, Wen-Xin; Xue, Zhe; Li, Lin; Wu, Chen; Zhang, Yan-Yang; Lou, Xin; Ma, Lin; Sun, Zheng-Hui

2017-04-01

Intracranial mirror aneurysms are clinically rare and uncommonly reported in the literature. Therefore, the present study evaluated a series of mirror aneurysm cases with respect to the clinical features of the patients and the treatment strategies that were used. This study retrospectively reviewed and systematically analyzed the clinical features, imaging data, treatment methods, and treatment outcomes of 68 cases of mirror aneurysms (a total of 70 pairs) in patients who were admitted to our department between November 2007 and May 2016. The patient population included 24 male and 44 female patients, with a mean age of 52 years. The mirror aneurysms were primarily located in posterior communicating artery and middle cerebral artery and 65 of the aneurysms were large or giant (≧10 mm). Of the 68 patients, 28 were treated by the clipping or embolization of all aneurysms in one stage, 16 were treated in 2 stages, 16 were treated by treating part of the aneurysms, and 8 were observed. The modified Rankin Scale scores of the 60 patients that were treated indicated that 52 had a good recovery (modified Rankin Scale score ≦2; 86.7%), and 1 patient died. Treatment strategies for mirror aneurysms should be determined individually according to the location, size, and morphology of the aneurysm, as well as the clinical manifestations of each patient. Furthermore, the responsible ruptured aneurysm should be given treatment priority, whereas the contralateral unruptured aneurysm should be observed or treated in either 1 or 2 stages. Copyright © 2017 Elsevier Inc. All rights reserved.

Magnetic resonance spectroscopic determination of a neuronal and axonal marker in white matter predicts reversibility of deficits in secondary normal pressure hydrocephalus

PubMed Central

Shiino, A; Nishida, Y; Yasuda, H; Suzuki, M; Matsuda, M; Inubushi, T

2004-01-01

Background: Normal pressure hydrocephalus (NPH) is considered to be a treatable form of dementia, because cerebrospinal fluid (CSF) shunting can lessen symptoms. However, neuroimaging has failed to predict when shunting will be effective. Objective: To investigate whether 1H (proton) magnetic resonance (MR) spectroscopy could predict functional outcome in patients after shunting. Methods: Neurological state including Hasegawa's dementia scale, gait, continence, and the modified Rankin scale were evaluated in 21 patients with secondary NPH who underwent ventriculo-peritoneal shunting. Outcomes were measured postoperatively at one and 12 months and were classified as excellent, fair, or poor. MR spectra were obtained from left hemispheric white matter. Results: Significant preoperative differences in N-acetyl aspartate (NAA)/creatine (Cr) and NAA/choline (Cho) were noted between patients with excellent and poor outcome at one month (p = 0.0014 and 0.0036, respectively). Multiple regression analysis linked higher preoperative NAA/Cr ratio, gait score, and modified Rankin scale to better one month outcome. Predictive value, sensitivity, and specificity for excellent outcome following shunting were 95.2%, 100%, and 87.5%. Multiple regression analysis indicated that NAA/Cho had the best predictive value for one year outcome (p = 0.0032); predictive value, sensitivity, and specificity were 89.5%, 90.0%, and 88.9%. Conclusions: MR spectroscopy predicted long term post-shunting outcomes in patients with secondary NPH, and it would be a useful assessment tool before lumbar drainage. PMID:15258216

Long term effectiveness of intravenous immunoglobulin in Churg-Strauss syndrome

PubMed Central

Danieli, M; Cappelli, M; Malcangi, G; Logullo, F; Salvi, A; Danieli, G

2004-01-01

Objective: To study the long term effectiveness of intravenous immunoglobulin and plasmapheresis associated with prednisone and cyclophosphamide in Churg-Strauss syndrome. Subjects and methods: We studied 18 subjects with new onset Churg-Strauss syndrome. All received the "standard" treatment based on prednisone (1 mg/kg/day for 1 month and then slowly tapered) and cyclophosphamide (2 mg/kg/day for 6 months in severe cases). In nine patients, synchronised cycles with plasmapheresis and intravenous immunoglobulin (2 g/kg) were repeated monthly for 6 months and every other month for a further three cycles. Clinical (disease activity monitored by Birmingham vasculitis activity score (BVAS) and damage index (modified Rankin score)) and functional (C reactive protein, blood eosinophil count, and electromyogram-electoneurogram) parameters were collected during treatment and the 3 year follow up period. Results: After 12 months, all patients in the treatment group and four (44%) in the control group were in remission. At the end of the 3 year follow up period, we documented significant differences in BVAS (p<0.01), global damage (p<0.02), modified Rankin score (p<0.04), and the daily maintenance prednisone dose (p<0.002) between the two groups. We found a tendency towards lower frequency of relapse and incidence of osteoporosis in the treatment group. Conclusion: Complete clinical and functional recovery with a long term stable remission and a low incidence of side effects can be achieved by intravenous immunoglobulin associated with plasmapheresis in patients with Churg-Strauss syndrome. PMID:15547090

Design and evaluation of fluidized bed heat recovery for diesel engine systems

NASA Technical Reports Server (NTRS)

Hamm, J. R.; Newby, R. A.; Vidt, E. J.; Lippert, T. E.

1985-01-01

The potential of utilizing fluidized bed heat exchangers in place of conventional counter-flow heat exchangers for heat recovery from adiabatic diesel engine exhaust gas streams was studied. Fluidized bed heat recovery systems were evaluated in three different heavy duty transport applications: (1) heavy duty diesel truck; (2) diesel locomotives; and (3) diesel marine pushboat. The three applications are characterized by differences in overall power output and annual utilization. For each application, the exhaust gas source is a turbocharged-adiabatic diesel core. Representative subposed exhaust gas heat utilization power cycles were selected for conceptual design efforts including design layouts and performance estimates for the fluidized bed heat recovery heat exchangers. The selected power cycles were: organic rankine with RC-1 working fluid, turbocompound power turbine with steam injection, and stirling engine. Fuel economy improvement predictions are used in conjunction with capital cost estimates and fuel price data to determine payback times for the various cases.

Compatibility of structural materials with liquid bismuth, lead, and mercury

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

Weeks, J.R.

1996-06-01

During the 1950s and 1960s, a substantial program existed at Brookhaven National Laboratory as part of the Liquid Metal Fuel reactor program on the compatibility of bismuth, lead, and their alloys with structural materials. Subsequently, compatibility investigations of mercury with structural materials were performed in support of development of Rankine cycle mercury turbines for nuclear applications. The present talk will review present understanding of the corrosion/mass-transfer reactions of structural materials with these liquid metal coolants. Topics to be discussed include the basic solubility relationships of iron, chromium, nickel, and refractory metals in these liquid metals, the results of inhibition studies,more » the role of oxygen on the corrosion processes, and specialized topics such as cavitation-corrosion and liquid metal embrittlement. Emphasis will be placed on utilizing the understanding gained in this earlier work on the development of heavy liquid metal targets in spallation neutron sources.« less

Method of moving frames to solve time-dependent Maxwell's equations on anisotropic curved surfaces: Applications to invisible cloak and ELF propagation

NASA Astrophysics Data System (ADS)

Chun, Sehun

2017-07-01

Applying the method of moving frames to Maxwell's equations yields two important advancements for scientific computing. The first is the use of upwind flux for anisotropic materials in Maxwell's equations, especially in the context of discontinuous Galerkin (DG) methods. Upwind flux has been available only to isotropic material, because of the difficulty of satisfying the Rankine-Hugoniot conditions in anisotropic media. The second is to solve numerically Maxwell's equations on curved surfaces without the metric tensor and composite meshes. For numerical validation, spectral convergences are displayed for both two-dimensional anisotropic media and isotropic spheres. In the first application, invisible two-dimensional metamaterial cloaks are simulated with a relatively coarse mesh by both the lossless Drude model and the piecewisely-parametered layered model. In the second application, extremely low frequency propagation on various surfaces such as spheres, irregular surfaces, and non-convex surfaces is demonstrated.

Lack of Early Improvement Predicts Poor Outcome Following Acute Intracerebral Hemorrhage.

PubMed

Yogendrakumar, Vignan; Smith, Eric E; Demchuk, Andrew M; Aviv, Richard I; Rodriguez-Luna, David; Molina, Carlos A; Silva Blas, Yolanda; Dzialowski, Imanuel; Kobayashi, Adam; Boulanger, Jean-Martin; Lum, Cheemun; Gubitz, Gord; Padma, Vasantha; Roy, Jayanta; Kase, Carlos S; Bhatia, Rohit; Ali, Myzoon; Lyden, Patrick; Hill, Michael D; Dowlatshahi, Dar

2018-04-01

There are limited data as to what degree of early neurologic change best relates to outcome in acute intracerebral hemorrhage. We aimed to derive and validate a threshold for early postintracerebral hemorrhage change that best predicts 90-day outcomes. Derivation: retrospective analysis of collated clinical stroke trial data (Virtual International Stroke Trials Archive). retrospective analysis of a prospective multicenter cohort study (Prediction of haematoma growth and outcome in patients with intracerebral haemorrhage using the CT-angiography spot sign [PREDICT]). Neurocritical and ICUs. Patients with acute intracerebral hemorrhage presenting less than 6 hours. Derivation: 552 patients; validation: 275 patients. None. We generated a receiver operating characteristic curve for the association between 24-hour National Institutes of Health Stroke Scale change and clinical outcome. The primary outcome was a modified Rankin Scale score of 4-6 at 90 days; secondary outcomes were other modified Rankin Scale score ranges (modified Rankin Scale, 2-6, 3-6, 5-6, 6). We employed Youden's J Index to select optimal cut points and calculated sensitivity, specificity, and predictive values. We determined independent predictors via multivariable logistic regression. The derived definitions were validated in the PREDICT cohort. Twenty-four-hour National Institutes of Health Stroke Scale change was strongly associated with 90-day outcome with an area under the receiver operating characteristic curve of 0.75. Youden's method showed an optimum cut point at -0.5, corresponding to National Institutes of Health Stroke Scale change of greater than or equal to 0 (a lack of clinical improvement), which was seen in 46%. Early neurologic change accurately predicted poor outcome when defined as greater than or equal to 0 (sensitivity, 65%; specificity, 73%; positive predictive value, 70%; adjusted odds ratio, 5.05 [CI, 3.25-7.85]) or greater than or equal to 4 (sensitivity, 19%; specificity, 98%; positive predictive value, 91%; adjusted odds ratio, 12.24 [CI, 4.08-36.66]). All definitions reproduced well in the validation cohort. Lack of clinical improvement at 24 hours robustly predicted poor outcome and showed good discrimination for individual patients who would do poorly. These findings are useful for prognostication and may also present as a potential early surrogate outcome for future intracerebral hemorrhage treatment trials.

Embolization as one modality in a combined strategy for the management of cerebral arteriovenous malformations.

PubMed

Raymond, J; Iancu, D; Weill, A; Guilbert, F; Bahary, J P; Bojanowski, M; Roy, D

2005-10-05

We attempted to assess clinical results of management of cerebral arteriovenous malformation using a combination of endovascular, surgical and radiotherapeutic approaches. We retrospectively reviewed the angiographic and clinical data on prospectively collected consecutive patients treated by embolization from 1994 to 2004. The general philosophy was to attempt treatment by a combination of approaches only when an angiographic cure was likely or at least possible. The clinical outcome was assessed according to the modified Rankin scale. Although 404 patients were collected, complete files and follow-ups are available for 227 or 56% only. Most patients presented with hemorrhages (53%) or seizures (23%). The final management consisted in embolization alone in 34%, embolization followed by surgery in 47%, embolization and radiotherapy in 16%, and embolization, surgery and radiotherapy in 3% of patients. The embolization procedure itself could lead to an angiographic cure in only 16% of patients. When the management strategy could be completed, the cure rate increased to 66%. Complications of embolization occurred in 22.6% of patients. Overall clinical outcome was excellent (Rankin 0) in 43%, good (Rankin 1) in 38%, fair (Rankin 2) in 10%, poor (Rankin 3-5) in 2%, and the death rate was 7%. A combined strategy initially designed to provide angiographic cures cannot be completed in a significant number of patients; the total morbidity of treatment remains significant. There is no scientific evidence that cerebral arteriovenous malformations should be treated, and no clinical trial to prove that one approach is better than the other. Various treatment protocols have been proposed on empirical grounds. Small lesions can often be eradicated, with surgery when lesions are superficial, or with radiation therapy for deeper ones. There has been little controversy regarding therapeutic indications in these patients (1). The management of larger AVMs, sometimes in more eloquent locations, is much more difficult and controversial (2-4). Endovascular approaches have initially been developed to meet this challenge (5,6). It became quickly evident that embolization alone would rarely suffice to completely cure these lesions. The philosophy behind combined approaches is founded on 2 opinions: 1) There is no proven value of partial embolization, not even "partial benefits", and treatment should aim at an angiographic cure (7) and 2) By appropriately tailoring all available tools to each situation, such a cure could be reached with minimum or reasonable risks. We have used such a combined strategy for more than a decade now. Endovascular techniques and materials have evolved, and it is perhaps possible today to reach a cure by embolization alone in a larger proportion of patients than before (8). Aggressive embolizations, aiming for an endovascular cure, even sometimes in large lesions, have recently been promoted for their power or criticized for their risks (9). But before evaluating the advantages and inconveniences of new treatments, it may be wise to review the results we could achieve with a conventional approach combining endovascular, surgical and radiotherapeutic techniques.

Design and optimization of organic rankine cycle for low temperature geothermal power plant

NASA Astrophysics Data System (ADS)

Barse, Kirtipal A.

Rising oil prices and environmental concerns have increased attention to renewable energy. Geothermal energy is a very attractive source of renewable energy. Although low temperature resources (90°C to 150°C) are the most common and most abundant source of geothermal energy, they were not considered economical and technologically feasible for commercial power generation. Organic Rankine Cycle (ORC) technology makes it feasible to use low temperature resources to generate power by using low boiling temperature organic liquids. The first hypothesis for this research is that using ORC is technologically and economically feasible to generate electricity from low temperature geothermal resources. The second hypothesis for this research is redesigning the ORC system for the given resource condition will improve efficiency along with improving economics. ORC model was developed using process simulator and validated with the data obtained from Chena Hot Springs, Alaska. A correlation was observed between the critical temperature of the working fluid and the efficiency for the cycle. Exergy analysis of the cycle revealed that the highest exergy destruction occurs in evaporator followed by condenser, turbine and working fluid pump for the base case scenarios. Performance of ORC was studied using twelve working fluids in base, Internal Heat Exchanger and turbine bleeding constrained and non-constrained configurations. R601a, R245ca, R600 showed highest first and second law efficiency in the non-constrained IHX configuration. The highest net power was observed for R245ca, R601a and R601 working fluids in the non-constrained base configuration. Combined heat exchanger area and size parameter of the turbine showed an increasing trend as the critical temperature of the working fluid decreased. The lowest levelized cost of electricity was observed for R245ca followed by R601a, R236ea in non-constrained base configuration. The next best candidates in terms of LCOE were R601a, R245ca and R600 in non-constrained IHX configuration. LCOE is dependent on net power and higher net power favors to lower the cost of electricity. Overall R245ca, R601, R601a, R600 and R236ea show better performance among the fluids studied. Non constrained configurations display better performance compared to the constrained configurations. Base non-constrained offered the highest net power and lowest LCOE.

Spaceborne power systems preference analyses. Volume 2: Decision analysis

NASA Technical Reports Server (NTRS)

Smith, J. H.; Feinberg, A.; Miles, R. F., Jr.

1985-01-01

Sixteen alternative spaceborne nuclear power system concepts were ranked using multiattribute decision analysis. The purpose of the ranking was to identify promising concepts for further technology development and the issues associated with such development. Four groups were interviewed to obtain preference. The four groups were: safety, systems definition and design, technology assessment, and mission analysis. The highest ranked systems were the heat-pipe thermoelectric systems, heat-pipe Stirling, in-core thermionic, and liquid-metal thermoelectric systems. The next group contained the liquid-metal Stirling, heat-pipe Alkali Metal Thermoelectric Converter (AMTEC), heat-pipe Brayton, liquid-metal out-of-core thermionic, and heat-pipe Rankine systems. The least preferred systems were the liquid-metal AMTEC, heat-pipe thermophotovoltaic, liquid-metal Brayton and Rankine, and gas-cooled Brayton. The three nonheat-pipe technologies selected matched the top three nonheat-pipe systems ranked by this study.

Development of a solar receiver for an organic Rankine cycle engine

NASA Astrophysics Data System (ADS)

Haskins, H. J.; Taylor, R. M.; Osborn, D. B.

A prototype power conversion assembly (PCA) developed by an American aerospace company is considered. The PCA will be mounted at the focal point of a 12 meter parabolic dish and will produce approximately 20 kW of 3 kHz ac power to a ground-mounted rectifier. The PCA includes a cavity receiver coupled to an organic Rankine cycle engine. The engine working fluid is toluene. The performance goals of the receiver design are to maximize both the thermal efficiency and the heat capacity of the core. The latter goal is desired for stabilizing the PCA operation during intermittent cloud cover. The receiver design is based upon the utilization of a direct-heated copper shell. It was necessary to develop a feasible manufacturing process for assuring a good braze joint between the stainless steel, containing the toluene, and the copper shell.

Dry Air Cooler Modeling for Supercritical Carbon Dioxide Brayton Cycle Analysis

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

Moisseytsev, A.; Sienicki, J. J.; Lv, Q.

Modeling for commercially available and cost effective dry air coolers such as those manufactured by Harsco Industries has been implemented in the Argonne National Laboratory Plant Dynamics Code for system level dynamic analysis of supercritical carbon dioxide (sCO 2) Brayton cycles. The modeling can now be utilized to optimize and simulate sCO 2 Brayton cycles with dry air cooling whereby heat is rejected directly to the atmospheric heat sink without the need for cooling towers that require makeup water for evaporative losses. It has sometimes been stated that a benefit of the sCO 2 Brayton cycle is that it enablesmore » dry air cooling implying that the Rankine steam cycle does not. A preliminary and simple examination of a Rankine superheated steam cycle and an air-cooled condenser indicates that dry air cooling can be utilized with both cycles provided that the cycle conditions are selected appropriately« less

Rankline-Brayton engine powered solar thermal aircraft

DOEpatents

Bennett, Charles L [Livermore, CA

2012-03-13

A solar thermal powered aircraft powered by heat energy from the sun. A Rankine-Brayton hybrid cycle heat engine is carried by the aircraft body for producing power for a propulsion mechanism, such as a propeller or other mechanism for enabling sustained free flight. The Rankine-Brayton engine has a thermal battery, preferably containing a lithium-hydride and lithium mixture, operably connected to it so that heat is supplied from the thermal battery to a working fluid. A solar concentrator, such as reflective parabolic trough, is movably connected to an optically transparent section of the aircraft body for receiving and concentrating solar energy from within the aircraft. Concentrated solar energy is collected by a heat collection and transport conduit, and heat transported to the thermal battery. A solar tracker includes a heliostat for determining optimal alignment with the sun, and a drive motor actuating the solar concentrator into optimal alignment with the sun based on a determination by the heliostat.

Development of a solar receiver for an organic Rankine cycle engine

NASA Technical Reports Server (NTRS)

Haskins, H. J.; Taylor, R. M.; Osborn, D. B.

1981-01-01

A prototype power conversion assembly (PCA) developed by an American aerospace company is considered. The PCA will be mounted at the focal point of a 12 meter parabolic dish and will produce approximately 20 kW of 3 kHz ac power to a ground-mounted rectifier. The PCA includes a cavity receiver coupled to an organic Rankine cycle engine. The engine working fluid is toluene. The performance goals of the receiver design are to maximize both the thermal efficiency and the heat capacity of the core. The latter goal is desired for stabilizing the PCA operation during intermittent cloud cover. The receiver design is based upon the utilization of a direct-heated copper shell. It was necessary to develop a feasible manufacturing process for assuring a good braze joint between the stainless steel, containing the toluene, and the copper shell.

Overview of waste heat utilization systems

NASA Technical Reports Server (NTRS)

Bailey, M. M.

1984-01-01

The heavy truck diesel engine rejects a significant fraction of its fuel energy in the form of waste heat. Historically, the Department of Energy has supported technology efforts for utilization of the diesel exhaust heat. Specifically, the Turbocompound and the Organic Rankine Cycle System (ORCS) have demonstrated that meaningful improvements in highway fuel economy can be realized through waste heat utilization. For heat recovery from the high temperature exhaust of future adiabatic diesel engines, the DOE/NASA are investigating a variety of alternatives based on the Rankine, Brayton, and Stirling power cycles. Initial screening results indicate that systems of this type offer a fuel savings advantage over the turbocompound system. Capital and maintenance cost projections, however, indicate that the alternative power cycles are not competitive on an economic payback basis. Plans call for continued analysis in an attempt to identify a cost effective configuration with adequate fuel savings potential.

Integrated heat pipe-thermal storage system performance evaluation

NASA Technical Reports Server (NTRS)

Keddy, E.; Sena, J. T.; Merrigan, M.; Heidenreich, Gary

1987-01-01

An integrated thermal energy storage (TES) system, developed as a part of an organic Rankine cycle solar dynamic power system is described, and the results of the performance verification tests of this TES system are presented. The integrated system consists of potassium heat-pipe elements that incorporate TES canisters within the vapor space, along with an organic fluid heater tube used as the condenser region of the heat pipe. The heat pipe assembly was operated through the range of design conditions from the nominal design input of 4.8 kW to a maximum of 5.7 kW. The performance verification tests show that the system meets the functional requirements of absorbing the solar energy reflected by the concentrator, transporting the energy to the organic Rankine heater, providing thermal storage for the eclipse phase, and allowing uniform discharge from the thermal storage to the heater.

The performance of solar thermal electric power systems employing small heat engines

NASA Technical Reports Server (NTRS)

Pons, R. L.

1980-01-01

The paper presents a comparative analysis of small (10 to 100 KWe) heat engines for use with a solar thermal electric system employing the point-focusing, distributed receiver (PF-DR) concept. Stirling, Brayton, and Rankine cycle engines are evaluated for a nominal overall system power level of 1 MWe, although the concept is applicable to power levels up to at least 10 MWe. Multiple concentrators are electrically connected to achieve the desired plant output. Best performance is achieved with the Stirling engine, resulting in a system Levelized Busbar Energy Cost of just under 50 mills/kWH and a Capital Cost of $900/kW, based on the use of mass-produced components. Brayton and Rankine engines show somewhat less performance but are viable alternatives with particular benefits for special applications. All three engines show excellent performance for the small community application.

STAGS Developments for Residual Strength Analysis Methods for Metallic Fuselage Structures

NASA Technical Reports Server (NTRS)

Young, Richard D.; Rose, Cheryl A.

2014-01-01

A summary of advances in the Structural Analysis of General Shells (STAGS) finite element code for the residual strength analysis of metallic fuselage structures, that were realized through collaboration between the structures group at NASA Langley, and Dr. Charles Rankin is presented. The majority of the advancements described were made in the 1990's under the NASA Airframe Structural Integrity Program (NASIP). Example results from studies that were conducted using the STAGS code to develop improved understanding of the nonlinear response of cracked fuselage structures subjected to combined loads are presented. An integrated residual strength analysis methodology for metallic structure that models crack growth to predict the effect of cracks on structural integrity is demonstrated

Structural Integrity of Normal Appearing White Matter and Sex-Specific Outcomes After Acute Ischemic Stroke.

PubMed

Etherton, Mark R; Wu, Ona; Cougo, Pedro; Giese, Anne-Katrin; Cloonan, Lisa; Fitzpatrick, Kaitlin M; Kanakis, Allison S; Boulouis, Gregoire; Karadeli, Hasan H; Lauer, Arne; Rosand, Jonathan; Furie, Karen L; Rost, Natalia S

2017-12-01

Women have worse poststroke outcomes than men. We evaluated sex-specific clinical and neuroimaging characteristics of white matter in association with functional recovery after acute ischemic stroke. We performed a retrospective analysis of acute ischemic stroke patients with admission brain MRI and 3- to 6-month modified Rankin Scale score. White matter hyperintensity and acute infarct volume were quantified on fluid-attenuated inversion recovery and diffusion tensor imaging MRI, respectively. Diffusivity anisotropy metrics were calculated in normal appearing white matter contralateral to the acute ischemia. Among 319 patients with acute ischemic stroke, women were older (68.0 versus 62.7 years; P =0.004), had increased incidence of atrial fibrillation (21.4% versus 12.2%; P =0.04), and lower rate of tobacco use (21.1% versus 35.9%; P =0.03). There was no sex-specific difference in white matter hyperintensity volume, acute infarct volume, National Institutes of Health Stroke Scale, prestroke modified Rankin Scale score, or normal appearing white matter diffusivity anisotropy metrics. However, women were less likely to have an excellent outcome (modified Rankin Scale score <2: 49.6% versus 67.0%; P =0.005). In logistic regression analysis, female sex and the interaction of sex with fractional anisotropy, radial diffusivity, and axial diffusivity were independent predictors of functional outcome. Female sex is associated with decreased likelihood of excellent outcome after acute ischemic stroke. The correlation between markers of white matter integrity and functional outcomes in women, but not men, suggests a potential sex-specific mechanism. © 2017 American Heart Association, Inc.

Importance of frailty evaluation in the prediction of the prognosis of patients with chronic subdural hematoma.

PubMed

Shimizu, Kiyoharu; Sadatomo, Takashi; Hara, Takeshi; Onishi, Shumpei; Yuki, Kiyoshi; Kurisu, Kaoru

2018-05-17

The present study aimed to clarify the relationship between frailty and prognosis of patients with chronic subdural hematoma. This retrospective study involved 211 patients aged ≥65 years with chronic subdural hematoma, who underwent surgery at Higashihiroshima Medical Center, Hiroshima, Japan, between July 2011 and May 2017. The study outcome was the patient's modified Rankin Scale score at 3 months after surgery. A logistic regression analysis was carried out to analyze factors that influenced the outcome. Chronic subdural hematoma patients with frailty had a poorer prognosis than those without (median modified Rankin Scale: 4 and 2, P < 0.001; proportions of patients discharged to home: 35% and 91%, P < 0.001, respectively). After adjusting for patients' background, the patients' modified Rankin Scale scores at 3 months after surgery were found to be associated with age, controlling nutritional status score and recurrence, but not with frailty. However, receiver operating characteristic curves of the model with the Clinical Frailty Scale were more accurately correlated with prognosis than those of the model without this scale (area under the curve 0.98, 95% confidence interval 0.96-0.99; and 0.87, 95% confidence interval 0.82-0.91, respectively.) CONCLUSIONS: Chronic subdural hematoma patients with frailty had poorer prognosis than those without. The evaluation of the presence of frailty on admission can be an important factor in the prediction of the prognosis of chronic subdural hematoma patients. Geriatr Gerontol Int 2018; ••: ••-••. © 2018 Japan Geriatrics Society.

Dish-mounted latent heat buffer storage

NASA Technical Reports Server (NTRS)

Manvi, R.

1981-01-01

Dish-mounted latent heat storage subsystems for Rankine, Brayton, and Stirling engines operating at 427 C, 816 C, and 816 C respectively are discussed. Storage requirements definition, conceptual design, media stability and compatibility tests, and thermal performance analyses are considered.

Influence of racial differences on outcomes after thrombolytic therapy in acute ischemic stroke.

PubMed

Mishra, Nishant K; Mandava, Pitchaiah; Chen, Christopher; Grotta, James; Lees, Kennedy R; Kent, Thomas A

2014-07-01

The National Institutes of Neurological Disorders and Stroke and the European Co-operative Acute Stroke III trials enrolled a largely Caucasian population, but the results are often extrapolated onto non-Caucasians. A limited number of nonrandomized studies have proposed that non-Caucasian patients show differential response to tissue plasminogen activator. We examined if non-Caucasian patients of mixed national origin within the Virtual International Stroke Trials Archives neuroprotection trials responded differently to tissue plasminogen activator compared with Caucasians. We matched patients within each race-subtype for age, baseline National Institutes of Health Stroke Scales, and diabetes status, and excluded outliers. We tested for an interaction of race ethnicity with tissue plasminogen activator on predicting outcomes at α = 0·05. We compared 90-day ordinal outcome (modified Rankin Scale; primary analysis) and dichotomized outcomes (modified Rankin Scale 0-1; modified Rankin Scale 0-2; survival) within individual race ethnicity. One thousand nine hundred forty-six thrombolysed patients (125 Blacks, 39 Asians, and 1821 Caucasians) were matched with 1946 non-thrombolysed patients in each race ethnicity group. Postmatching, there were no imbalances in baseline National Institutes of Health Stroke Scales and age between the groups (P > 0·05). The interaction of tissue plasminogen activator with race ethnicity was nonsignificant in ordinal (P = 0·4) and in dichotomized outcome models (P > 0·05). Ordinal odds for improved outcomes were 1·5 for all patients (P < 0·05). Ordinal odds for Caucasians were 1·5 (P < 0·05); for Blacks, 2·1 (P < 0·05); and for Asians, 1·2 (P > 0·05; 1·6 after 1:2 matching with nonthrombolysed, because of small numbers). Dichotomized functional outcomes improved after thrombolysis overall, in Caucasians, in Blacks (modified Rankin Scale 0-2 only), and in Asians (after 1:2 matching; P > 0·05). Odds for survival were consistent across all groups. These results do not suggest a differential response to tissue plasminogen activator based on race ethnicity. Among Asians, data were particularly sparse, and results should be interpreted with caution. © 2013 The Authors. International Journal of Stroke © 2013 World Stroke Organization.

Prediction of two month modified Rankin Scale with an ordinal prediction model in patients with aneurysmal subarachnoid haemorrhage

PubMed Central

2010-01-01

Background Aneurysmal subarachnoid haemorrhage (aSAH) is a devastating event with a frequently disabling outcome. Our aim was to develop a prognostic model to predict an ordinal clinical outcome at two months in patients with aSAH. Methods We studied patients enrolled in the International Subarachnoid Aneurysm Trial (ISAT), a randomized multicentre trial to compare coiling and clipping in aSAH patients. Several models were explored to estimate a patient's outcome according to the modified Rankin Scale (mRS) at two months after aSAH. Our final model was validated internally with bootstrapping techniques. Results The study population comprised of 2,128 patients of whom 159 patients died within 2 months (8%). Multivariable proportional odds analysis identified World Federation of Neurosurgical Societies (WFNS) grade as the most important predictor, followed by age, sex, lumen size of the aneurysm, Fisher grade, vasospasm on angiography, and treatment modality. The model discriminated moderately between those with poor and good mRS scores (c statistic = 0.65), with minor optimism according to bootstrap re-sampling (optimism corrected c statistic = 0.64). Conclusion We presented a calibrated and internally validated ordinal prognostic model to predict two month mRS in aSAH patients who survived the early stage up till a treatment decision. Although generalizability of the model is limited due to the selected population in which it was developed, this model could eventually be used to support clinical decision making after external validation. Trial Registration International Standard Randomised Controlled Trial, Number ISRCTN49866681 PMID:20920243

Handbook of data on selected engine components for solar thermal applications

NASA Technical Reports Server (NTRS)

1979-01-01

A data base on developed and commercially available power conversion system components for Rankine and Brayton cycle engines, which have potential application to solar thermal power-generating systems is presented. The status of the Stirling engine is discussed.

77 FR 58903 - Mississippi Disaster Number MS-00059

Federal Register 2010, 2011, 2012, 2013, 2014

2012-09-24

..., Madison, Newton, Perry, Rankin, Simpson, Wayne, Yazoo. Alabama: Choctaw. Louisiana: Concordia, East Carroll, East Feliciana, Madison, Saint Helena, Tangipahoa, Tensas, West Feliciana. All other information... and 59008) James E. Rivera, Associate Administrator for Disaster Assistance. [FR Doc. 2012-23408 Filed...

Modeling of a Turbofan Engine with Ice Crystal Ingestion in the NASA Propulsion System Laboratory

NASA Technical Reports Server (NTRS)

Veres, Joseph P.; Jorgenson, Philip C. E.; Jones, Scott M.; Nili, Samaun

2017-01-01

The main focus of this study is to apply a computational tool for the flow analysis of the turbine engine that has been tested with ice crystal ingestion in the Propulsion Systems Laboratory (PSL) at NASA Glenn Research Center. The PSL has been used to test a highly instrumented Honeywell ALF502R-5A (LF11) turbofan engine at simulated altitude operating conditions. Test data analysis with an engine cycle code and a compressor flow code was conducted to determine the values of key icing parameters, that can indicate the risk of ice accretion, which can lead to engine rollback (un-commanded loss of engine thrust). The full engine aerothermodynamic performance was modeled with the Honeywell Customer Deck specifically created for the ALF502R-5A engine. The mean-line compressor flow analysis code, which includes a code that models the state of the ice crystal, was used to model the air flow through the fan-core and low pressure compressor. The results of the compressor flow analyses included calculations of the ice-water flow rate to air flow rate ratio (IWAR), the local static wet bulb temperature, and the particle melt ratio throughout the flow field. It was found that the assumed particle size had a large effect on the particle melt ratio, and on the local wet bulb temperature. In this study the particle size was varied parametrically to produce a non-zero calculated melt ratio in the exit guide vane (EGV) region of the low pressure compressor (LPC) for the data points that experienced a growth of blockage there, and a subsequent engine called rollback (CRB). At data points where the engine experienced a CRB having the lowest wet bulb temperature of 492 degrees Rankine at the EGV trailing edge, the smallest particle size that produced a non-zero melt ratio (between 3 percent - 4 percent) was on the order of 1 micron. This value of melt ratio was utilized as the target for all other subsequent data points analyzed, while the particle size was varied from 1 micron - 9.5 microns to achieve the target melt ratio. For data points that did not experience a CRB which had static wet bulb temperatures in the EGV region below 492 degrees Rankine, a non-zero melt ratio could not be achieved even with a 1 micron ice particle size. The highest value of static wet bulb temperature for data points that experienced engine CRB was 498 degrees Rankine with a particle size of 9.5 microns. Based on this study of the LF11 engine test data, the range of static wet bulb temperature at the EGV exit for engine CRB was in the narrow range of 492 degrees Rankine - 498 degrees Rankine , while the minimum value of IWAR was 0.002. The rate of blockage growth due to ice accretion and boundary layer growth was estimated by scaling from a known blockage growth rate that was determined in a previous study. These results obtained from the LF11 engine analysis formed the basis of a unique “icing wedge.”

Gigabit Nectar: Architecture and Performance.

DTIC Science & Technology

1995-09-01

proposed American National Standard for Information Systems, 1992. [3] Jose Arabe, Adam Beguelin, Bruce Lowekamp, Eric Seligman , Mike Starkey, and Peter...Shekhar Borkar, Robert Cohn, George Cox, Sha Gleason, Thomas Gross, H. T. Kung, Monica Lam, Brian Moore, Craig Peterson, John Pieper, Linda Rankin, P

77 FR 55220 - Mississippi; Major Disaster and Related Determinations

Federal Register 2010, 2011, 2012, 2013, 2014

2012-09-07

... removal and emergency protective measures (Categories A and B), including direct Federal assistance, under..., Lawrence, Lincoln, Madison, Marion, Montgomery, Pearl River, Perry, Pike, Rankin, Stone, Walthall, Wayne, Wilkinson, and Yazoo Counties for debris removal and emergency protective measures (Categories A and B...

Convergence acceleration of molecular dynamics methods for shocked materials using velocity scaling

NASA Astrophysics Data System (ADS)

Taylor, DeCarlos E.

2017-03-01

In this work, a convergence acceleration method applicable to extended system molecular dynamics techniques for shock simulations of materials is presented. The method uses velocity scaling to reduce the instantaneous value of the Rankine-Hugoniot conservation of energy constraint used in extended system molecular dynamics methods to more rapidly drive the system towards a converged Hugoniot state. When used in conjunction with the constant stress Hugoniostat method, the velocity scaled trajectories show faster convergence to the final Hugoniot state with little difference observed in the converged Hugoniot energy, pressure, volume and temperature. A derivation of the scale factor is presented and the performance of the technique is demonstrated using the boron carbide armour ceramic as a test material. It is shown that simulation of boron carbide Hugoniot states, from 5 to 20 GPa, using both a classical Tersoff potential and an ab initio density functional, are more rapidly convergent when the velocity scaling algorithm is applied. The accelerated convergence afforded by the current algorithm enables more rapid determination of Hugoniot states thus reducing the computational demand of such studies when using expensive ab initio or classical potentials.

Outcome After Reperfusion Therapies in Patients With Large Baseline Diffusion-Weighted Imaging Stroke Lesions: A THRACE Trial (Mechanical Thrombectomy After Intravenous Alteplase Versus Alteplase Alone After Stroke) Subgroup Analysis.

PubMed

Gautheron, Vincent; Xie, Yu; Tisserand, Marie; Raoult, Hélène; Soize, Sébastien; Naggara, Olivier; Bourcier, Romain; Richard, Sébastien; Guillemin, Francis; Bracard, Serge; Oppenheim, Catherine

2018-03-01

Stroke patients with large diffusion-weighted imaging (DWI) volumes are often excluded from reperfusion because of reckoned futility. In those with DWI volume >70 mL, included in the THRACE trial (Mechanical Thrombectomy After Intravenous Alteplase Versus Alteplase Alone After Stroke), we report the associations between baseline parameters and outcome. We examined 304 patients with anterior circulation stroke and pretreatment magnetic resonance imaging. Variables were extracted from the THRACE database, and DWI volumes were measured semiautomatically. Among 53 patients with DWI volume >70 mL, 12 had favorable outcome (modified Rankin Scale score, ≤2) at 3 months; they had less coronary disease (0/12 versus 12/38; P =0.046) and less history of smoking (1/10 versus 12/31; P =0.013) than patients with modified Rankin Scale score >2. None of the 8 patients >75 years of age reached modified Rankin Scale score ≤2. Favorable outcome occurred in 12 of 37 M1-occluded patients but in 0 of 16 internal carotid-T/L-occluded patients ( P =0.010). Favorable outcome was more frequent (6/13) when DWI lesion was limited to the superficial middle cerebral artery territory than when it extended to the deep middle cerebral artery territory (6/40; P =0.050). Stroke patients with DWI lesion >70 mL may benefit from reperfusion therapy, especially those with isolated M1 occlusion or ischemia restricted to the superficial middle cerebral artery territory. The benefit of treatment seems questionable for patients with carotid occlusion or lesion extending to the deep middle cerebral artery territory. © 2018 American Heart Association, Inc.

Thrombectomy in patients ineligible for iv tPA (THRILL).

PubMed

Bendszus, Martin; Thomalla, Götz; Knauth, Michael; Hacke, Werner; Bonekamp, Susanne; Fiehler, Jens

2015-08-01

A relevant proportion of patients with acute ischemic stroke are ineligible for intravenous thrombolysis with recombinant tissue plasminogen activator. Mechanical thrombectomy offers a treatment alternative for these patients; however, only few data are available on its safety and efficacy. The aim of this study was to compare safety and efficacy of stent retrievers as device class with best medical care alone in acute stroke patients with large intracranial vessel occlusion in the anterior circulation who are not eligible for intravenous thrombolysis with recombinant tissue plasminogen activator up to eight-hours of symptom onset. 'Thrombectomy in patients ineligible for iv tPA' is a prospective, open-label, blinded end-point, binational (Germany and Austria), two-arm, randomized, controlled, post-market study. Primary end-point is the modified Rankin Score shift analysis 90 days (±14) after stroke. Secondary end-points are excellent neurological outcomes (modified Rankin Score ≤ 1), good neurological outcomes (modified Rankin Score ≤ 2 or National Institutes of Health Stroke Scale improvement ≥ 10), difference between predicted infarct volume and actual core infarct volume (computed tomography or magnetic resonance imaging) at 30 (±6) h post-ictus, successful recanalization (thrombolysis in cerebral infarction score 2b or 3), functional health status 90 (±14) days after stroke (European Quality of Life-5 Dimensions) as well as common safety end-points (adverse event, serious adverse event, symptomatic intracranial haemorrhage at 30 (±6) h, death, or dependency). Whether mechanical thrombectomy in patients with acute ischemic stroke who are not eligible for intravenous thrombolysis with recombinant tissue plasminogen activator improves clinical outcomes is unclear. 'Thrombectomy in patients ineligible for iv tPA' may change clinical practice by providing evidence of an effective and safe treatment for such patients. © 2015 World Stroke Organization.

Validation of the DRAGON score in 12 stroke centers in anterior and posterior circulation.

PubMed

Strbian, Daniel; Seiffge, David J; Breuer, Lorenz; Numminen, Heikki; Michel, Patrik; Meretoja, Atte; Coote, Skye; Bordet, Régis; Obach, Victor; Weder, Bruno; Jung, Simon; Caso, Valeria; Curtze, Sami; Ollikainen, Jyrki; Lyrer, Philippe A; Eskandari, Ashraf; Mattle, Heinrich P; Chamorro, Angel; Leys, Didier; Bladin, Christopher; Davis, Stephen M; Köhrmann, Martin; Engelter, Stefan T; Tatlisumak, Turgut

2013-10-01

The DRAGON score predicts functional outcome in the hyperacute phase of intravenous thrombolysis treatment of ischemic stroke patients. We aimed to validate the score in a large multicenter cohort in anterior and posterior circulation. Prospectively collected data of consecutive ischemic stroke patients who received intravenous thrombolysis in 12 stroke centers were merged (n=5471). We excluded patients lacking data necessary to calculate the score and patients with missing 3-month modified Rankin scale scores. The final cohort comprised 4519 eligible patients. We assessed the performance of the DRAGON score with area under the receiver operating characteristic curve in the whole cohort for both good (modified Rankin scale score, 0-2) and miserable (modified Rankin scale score, 5-6) outcomes. Area under the receiver operating characteristic curve was 0.84 (0.82-0.85) for miserable outcome and 0.82 (0.80-0.83) for good outcome. Proportions of patients with good outcome were 96%, 93%, 78%, and 0% for 0 to 1, 2, 3, and 8 to 10 score points, respectively. Proportions of patients with miserable outcome were 0%, 2%, 4%, 89%, and 97% for 0 to 1, 2, 3, 8, and 9 to 10 points, respectively. When tested separately for anterior and posterior circulation, there was no difference in performance (P=0.55); areas under the receiver operating characteristic curve were 0.84 (0.83-0.86) and 0.82 (0.78-0.87), respectively. No sex-related difference in performance was observed (P=0.25). The DRAGON score showed very good performance in the large merged cohort in both anterior and posterior circulation strokes. The DRAGON score provides rapid estimation of patient prognosis and supports clinical decision-making in the hyperacute phase of stroke care (eg, when invasive add-on strategies are considered).

Autonomic Dysfunction Predicts Clinical Outcomes After Acute Ischemic Stroke: A Prospective Observational Study.

PubMed

Xiong, Li; Tian, Ge; Leung, Howan; Soo, Yannie O Y; Chen, Xiangyan; Ip, Vincent H L; Mok, Vincent C T; Chu, Winnie C W; Wong, Ka Sing; Leung, Thomas W H

2018-01-01

Central autonomic dysfunction increases stroke morbidity and mortality. We aimed to investigate whether poststroke autonomic dysfunction graded by Ewing battery can predict clinical outcome. In this prospective observational study, we assessed autonomic function of ischemic stroke patients within 7 days from symptom onset by Ewing battery. On the basis of the magnitude of autonomic dysfunction, we stratified patients into significant (definite, severe, or atypical) or minor (normal or early) autonomic function impairment groups and correlated the impairment with the 3-month modified Rankin Scale score (good outcome: modified Rankin Scale score 0≈2; poor outcome: modified Rankin Scale score 3≈6). Among the 150 patients enrolled (mean age, 66.4±9.9 years; 70.7% males), minor autonomic dysfunction was identified in 36 patients (24.0%), and significant autonomic dysfunction was identified in 114 patients (76.0%) based on Ewing battery. In 3 months, a poor functional outcome was found in 32.5% of significant group patients compared with 13.9% in the minor group ( P =0.031). Crude odds ratios of the magnitude of autonomic dysfunction and 3-month unfavorable functional outcome after acute ischemic stroke were 2.979 (95% confidence interval, 1.071-8.284; P =0.036). After adjusting for confounding variables with statistical significance between the 2 functional outcome subgroups identified in univariate analysis (including sex and National Institutes of Health Stroke Scale score on admission), the magnitude of autonomic dysfunction still independently predicted an unfavorable outcome, with an odds ratio of 3.263 (95% confidence interval, 1.141-9.335; P =0.027). Autonomic dysfunction gauged by Ewing battery predicts poor functional outcome after acute ischemic stroke. © 2017 American Heart Association, Inc.

Affordable Rankine Cycle Waste Heat Recovery for Heavy Duty Trucks

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

Subramanian, Swami Nathan

Nearly 30% of fuel energy is not utilized and wasted in the engine exhaust. Organic Rankine Cycle (ORC) based waste heat recovery (WHR) systems offer a promising approach on waste energy recovery and improving the efficiency of Heavy-Duty diesel engines. Major barriers in the ORC WHR system are the system cost and controversial waste heat recovery working fluids. More than 40% of the system cost is from the additional heat exchangers (recuperator, condenser and tail pipe boiler). The secondary working fluid loop designed in ORC system is either flammable or environmentally sensitive. The Eaton team investigated a novel approach tomore » reduce the cost of implementing ORC based WHR systems to Heavy-Duty (HD) Diesel engines while utilizing safest working fluids. Affordable Rankine Cycle (ARC) concept aimed to define the next generation of waste energy recuperation with a cost optimized WHR system. ARC project used engine coolant as the working fluid. This approach reduced the need for a secondary working fluid circuit and subsequent complexity. A portion of the liquid phase engine coolant has been pressurized through a set of working fluid pumps and used to recover waste heat from the exhaust gas recirculation (EGR) and exhaust tail pipe exhaust energy. While absorbing heat, the mixture is partially vaporized but remains a wet binary mixture. The pressurized mixed-phase engine coolant mixture is then expanded through a fixed-volume ratio expander that is compatible with two-phase conditions. Heat rejection is accomplished through the engine radiator, avoiding the need for a separate condenser. The ARC system has been investigated for PACCAR’s MX-13 HD diesel engine.« less

Twelve-Month Clinical and Quality-of-Life Outcomes in the Interventional Management of Stroke III Trial.

PubMed

Palesch, Yuko Y; Yeatts, Sharon D; Tomsick, Thomas A; Foster, Lydia D; Demchuk, Andrew M; Khatri, Pooja; Hill, Michael D; Jauch, Edward C; Jovin, Tudor G; Yan, Bernard; von Kummer, Rüdiger; Molina, Carlos A; Goyal, Mayank; Schonewille, Wouter J; Mazighi, Mikael; Engelter, Stefan T; Anderson, Craig; Spilker, Judith; Carrozzella, Janice; Ryckborst, Karla J; Janis, L Scott; Simpson, Annie; Simpson, Kit N; Broderick, Joseph P

2015-05-01

Randomized trials have indicated a benefit for endovascular therapy in appropriately selected stroke patients at 3 months, but data regarding outcomes at 12 months are currently lacking. We compared functional and quality-of-life outcomes at 12 months overall and by stroke severity in stroke patients treated with intravenous tissue-type plasminogen activator followed by endovascular treatment as compared with intravenous tissue-type plasminogen activator alone in the Interventional Management of Stroke III Trial. The key outcome measures were a modified Rankin Scale score ≤2 (functional independence) and the Euro-QoL EQ-5D, a health-related quality-of-life measure. 656 subjects with moderate-to-severe stroke (National Institutes of Health Stroke Scale ≥8) were enrolled at 58 centers in the United States (41 sites), Canada (7), Australia (4), and Europe (6). There was an interaction between treatment group and stroke severity in the repeated measures analysis of modified Rankin Scale ≤2 outcome (P=0.039). In the 204 participants with severe stroke (National Institutes of Health Stroke Scale ≥20), a greater proportion of the endovascular group had a modified Rankin Scale ≤2 (32.5%) at 12 months as compared with the intravenous tissue-type plasminogen activator group (18.6%, P=0.037); no difference was seen for the 452 participants with moderately severe strokes (55.6% versus 57.7%). In participants with severe stroke, the endovascular group had 35.2 (95% confidence interval: 2.1, 73.3) more quality-adjusted-days over 12 months as compared with intravenous tissue-type plasminogen activator alone. Endovascular therapy improves functional outcome and health-related quality-of-life at 12 months after severe ischemic stroke. URL: http://www.clinicaltrials.gov. Unique identifier: NCT00359424. © 2015 American Heart Association, Inc.

Determining the Number of Ischemic Strokes Potentially Eligible for Endovascular Thrombectomy: A Population-Based Study.

PubMed

Chia, Nicholas H; Leyden, James M; Newbury, Jonathan; Jannes, Jim; Kleinig, Timothy J

2016-05-01

Endovascular thrombectomy (ET) is standard-of-care for ischemic stroke patients with large vessel occlusion, but estimates of potentially eligible patients from population-based studies have not been published. Such data are urgently needed to rationally plan hyperacute services. Retrospective analysis determined the incidence of ET-eligible ischemic strokes in a comprehensive population-based stroke study (Adelaide, Australia 2009-2010). Stroke patients were stratified via a prespecified eligibility algorithm derived from recent ET trials comprising stroke subtype, pathogenesis, severity, premorbid modified Rankin Score, presentation delay, large vessel occlusion, and target mismatch penumbra. Recognizing centers may interpret recent ET trials either loosely or rigidly; 2 eligibility algorithms were applied: restrictive (key criteria modified Rankin Scale score 0-1, presentation delay <3.5 hours, and target mismatch penumbra) and permissive (modified Rankin Scale score 0-3 and presentation delay <5 hours). In a population of 148 027 people, 318 strokes occurred in the 1-year study period (crude attack rate 215 [192-240] per 100 000 person-years). The number of ischemic strokes eligible by restrictive criteria was 17/258 (7%; 95% confidence intervals 4%-10%) and by permissive criteria, an additional 16 were identified, total 33/258 (13%; 95% confidence intervals 9%-18%). Two of 17 patients (and 6/33 permissive patients) had thrombolysis contraindications. Using the restrictive algorithm, there were 11 (95% confidence intervals 4-18) potential ET cases per 100 000 person-years or 22 (95% confidence intervals 13-31) using the permissive algorithm. In this cohort, ≈7% of ischemic strokes were potentially eligible for ET (13% with permissive criteria). In similar populations, the permissive criteria predict that ≤22 strokes per 100 000 person-years may be eligible for ET. © 2016 American Heart Association, Inc.

The economical utilization of geothermal energy

NASA Astrophysics Data System (ADS)

Rose, G.

1982-12-01

The geothermal energy which is stored in hot dry rock could be theoretically utilized for the generation of power. The hot-dry-rock procedure can provide a flow of hot water. The considered binary system can transform the obtained thermal energy into electrical energy. The system makes use of a Rankine cycle with a working fluid having a low boiling point. Heat from the hot water is transferred to the working fluid. The present investigation is concerned with the development of a method for the calculation of the entire process. The results obtained with the computational method are to provide a basis for the determination of the operational characteristics. The development method is used for the study of a process based on the use of carbon dioxide as working fluid. The economics of a use of the hot-dry-rock process with the binary system is also investigated. It is found that the considered procedure is not economical. Economical operation requires, in particular, hot water supplied at a much lower cost.

Point Defect Properties in Iron Chromium Alloys

DTIC Science & Technology

2006-09-01

turbine Brayton cycle power converter, which enables the reactor to operate with a higher efficiency when compared to the traditional Rankine...9) Using a Taylor expansion of F around ~ ρ =1 and using equation (3), it becomes clear that this contribution is quadratic in ( ~ ρ - 1

76 FR 27644 - Ocean Transportation Intermediary License; Revocation

Federal Register 2010, 2011, 2012, 2013, 2014

2011-05-12

... 515, effective on the corresponding date shown below: License Number: 003152NF. Name: Cargo Crating Company, Ltd. dba Cargo, Shipping International dba Cargo, Forwarding International. Address: 6605 Rankin.... License Number: 020315NF. Name: World Cargo Express, Inc. Address: 9133 S. La Cienega Blvd., Suite 245...

Performance analysis of exhaust heat recovery using organic Rankine cycle in a passenger car with a compression ignition engine

NASA Astrophysics Data System (ADS)

Ghilvacs, M.; Prisecaru, T.; Pop, H.; Apostol, V.; Prisecaru, M.; Pop, E.; Popescu, Gh; Ciobanu, C.; Mohanad, A.; Alexandru, A.

2016-08-01

Compression ignition engines transform approximately 40% of the fuel energy into power available at the crankshaft, while the rest part of the fuel energy is lost as coolant, exhaust gases and other waste heat. An organic Rankine cycle (ORC) can be used to recover this waste heat. In this paper, the characteristics of a system combining a compression ignition engine with an ORC which recover the waste heat from the exhaust gases are analyzed. The performance map of the diesel engine is measured on an engine test bench and the heat quantities wasted by the exhaust gases are calculated over the engine's entire operating region. Based on this data, the working parameters of ORC are defined, and the performance of a combined engine-ORC system is evaluated across this entire region. The results show that the net power of ORC is 6.304kW at rated power point and a maximum of 10% reduction in brake specific fuel consumption can be achieved.

Organic Rankine cycle - review and research directions in engine applications

NASA Astrophysics Data System (ADS)

Panesar, Angad

2017-11-01

Waste heat to power conversion using Organic Rankine Cycles (ORC) is expected to play an important role in CO2 reductions from diesel engines. Firstly, a review of automotive ORCs is presented focusing on the pure working fluids, thermal architectures and expanders. The discussion includes, but is not limited to: R245fa, ethanol and water as fluids; series, parallel and cascade as architectures; dry saturated, superheated and supercritical as expansion conditions; and scroll, radial turbine and piston as expansion machines. Secondly, research direction in versatile expander and holistic architecture (NOx + CO2) are proposed. Benefits of using the proposed unconventional approaches are quantified using Ricardo Wave and Aspen HYSYS for diesel engine and ORC modelling. Results indicate that, the implementation of versatile piston expander tolerant to two-phase and using cyclopentane can potentially increase the highway drive cycle power by 8%. Furthermore, holistic architecture offering complete utilisation of charge air and exhaust recirculation heat increased the performance noticeably to 5% of engine power at the design point condition.

Preliminary operational results from the Willard solar power system

NASA Technical Reports Server (NTRS)

Fenton, D. L.; Abernathy, G. H.; Krivokapich, G.; Ellibee, D. E.; Chilton, V.

1980-01-01

The solar powered system located near Willard, New Mexico, generates mechanical or electrical power at a capacity of 19 kW (25 HP). The solar collection system incorporates east/west tracking parabolic trough collectors with a total aperture area of 1275 sq m (13,720 sq ft). The hot oil type thermal energy storage is sufficient for approximately 20 hours of power system operation. The system utilizes a reaction type turbine in conjunction with an organic Rankine cycle engine. Total collector field efficiency reaches a maximum of 20 percent near the winter solstice and about 50 percent during the summer. During the month of July, 1979, the system pumped 60 percent of the 35,300 cu m (28.6 acre-feet) of water delivered. Operating efficiencies for the turbine component, organic Rankine cycle engine and the complete power system are respectively 65 to 75 percent, 12 to 15 percent and 5 to 6 percent. Significant maintenance time was expended on both the collector and power systems throughout the operational period.

Preliminary operational results from the Willard solar power system

NASA Astrophysics Data System (ADS)

Fenton, D. L.; Abernathy, G. H.; Krivokapich, G.; Ellibee, D. E.; Chilton, V.

1980-05-01

The solar powered system located near Willard, New Mexico, generates mechanical or electrical power at a capacity of 19 kW (25 HP). The solar collection system incorporates east/west tracking parabolic trough collectors with a total aperture area of 1275 sq m (13,720 sq ft). The hot oil type thermal energy storage is sufficient for approximately 20 hours of power system operation. The system utilizes a reaction type turbine in conjunction with an organic Rankine cycle engine. Total collector field efficiency reaches a maximum of 20 percent near the winter solstice and about 50 percent during the summer. During the month of July, 1979, the system pumped 60 percent of the 35,300 cu m (28.6 acre-feet) of water delivered. Operating efficiencies for the turbine component, organic Rankine cycle engine and the complete power system are respectively 65 to 75 percent, 12 to 15 percent and 5 to 6 percent. Significant maintenance time was expended on both the collector and power systems throughout the operational period.

Monitoring environmental and related performance parameters for a Rankine-cycle turbine electric generator utilizing geothermal energy at the Gila Hot Springs, New Mexico

NASA Astrophysics Data System (ADS)

Starkey, A. H.; Icerman, L.

1984-08-01

The environmental effects associated with the operation of a privately owned Rankine-cycle turbogenerator unit using low temperature geothermal resources in the form of free-flowing hot springs to produce electricity in a remote, rural area were studied. The following conclusions pertain to the operation of the turbogenerator system: (1) the heat exchanger could not provide sufficient freon vapor at the required pressures to provide adequate thermal input to the turbine; (2) conversion or redesign of the condenser and return pump to function adequately represents a problem of unknown difficulty; (3) all pressure and heat transfer tests indicated that a custom designed heat exchanger built on-site would provide adequate vapor at pressures high enough to power a 10-kW (sub e) or perhaps larger generator; and (4) automated control systems are needed for the hot and cold water supplies and the freon return pump.

A Kinetic Approach to Propagation and Stability of Detonation Waves

NASA Astrophysics Data System (ADS)

Monaco, R.; Bianchi, M. Pandolfi; Soares, A. J.

2008-12-01

The problem of the steady propagation and linear stability of a detonation wave is formulated in the kinetic frame for a quaternary gas mixture in which a reversible bimolecular reaction takes place. The reactive Euler equations and related Rankine-Hugoniot conditions are deduced from the mesoscopic description of the process. The steady propagation problem is solved for a Zeldovich, von Neuman and Doering (ZND) wave, providing the detonation profiles and the wave thickness for different overdrive degrees. The one-dimensional stability of such detonation wave is then studied in terms of an initial value problem coupled with an acoustic radiation condition at the equilibrium final state. The stability equations and their initial data are deduced from the linearized reactive Euler equations and related Rankine-Hugoniot conditions through a normal mode analysis referred to the complex disturbances of the steady state variables. Some numerical simulations for an elementary reaction of the hydrogen-oxygen chain are proposed in order to describe the time and space evolution of the instabilities induced by the shock front perturbation.

Development of a Direct Evaporator for the Organic Rankine Cycle

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

Donna Post Guillen; Helge Klockow; Matthew Lehar

2011-02-01

This paper describes research and development currently underway to place the evaporator of an Organic Rankine Cycle (ORC) system directly in the path of a hot exhaust stream produced by a gas turbine engine. The main goal of this research effort is to improve cycle efficiency and cost by eliminating the usual secondary heat transfer loop. The project’s technical objective is to eliminate the pumps, heat exchangers and all other added cost and complexity of the secondary loop by developing an evaporator that resides in the waste heat stream, yet virtually eliminates the risk of a working fluid leakage intomore » the gaseous exhaust stream. The research team comprised of Idaho National Laboratory and General Electric Company engineers leverages previous research in advanced ORC technology to develop a new direct evaporator design that will reduce the ORC system cost by up to 15%, enabling the rapid adoption of ORCs for waste heat recovery.« less

An assessment of advanced technology for industrial cogeneration

NASA Technical Reports Server (NTRS)

Moore, N.

1983-01-01

The potential of advanced fuel utilization and energy conversion technologies to enhance the outlook for the increased use of industrial cogeneration was assessed. The attributes of advanced cogeneration systems that served as the basis for the assessment included their fuel flexibility and potential for low emissions, efficiency of fuel or energy utilization, capital equipment and operating costs, and state of technological development. Over thirty advanced cogeneration systems were evaluated. These cogeneration system options were based on Rankine cycle, gas turbine engine, reciprocating engine, Stirling engine, and fuel cell energy conversion systems. The alternatives for fuel utilization included atmospheric and pressurized fluidized bed combustors, gasifiers, conventional combustion systems, alternative energy sources, and waste heat recovery. Two advanced cogeneration systems with mid-term (3 to 5 year) potential were found to offer low emissions, multi-fuel capability, and a low cost of producing electricity. Both advanced cogeneration systems are based on conventional gas turbine engine/exhaust heat recovery technology; however, they incorporate advanced fuel utilization systems.

Thermodynamic analysis of performance improvement by reheat on the CO2 transcritical power cycle

NASA Astrophysics Data System (ADS)

Tuo, Hanfei

2012-06-01

The CO2 transcritical rankine power cycle has been widely investigated recently, because of its better temperature glide matching between sensible heat source and working fluid in vapor generator, and its desirable qualities, such as moderate critical point, little environment impact and low cost. A reheat CO2 transcritical power cycle with two stage expansion is presented to improve baseline cycle performance in this paper. Energy and exergy analysis are carried out to investigate effects of important parameters on cycle performance. The main results show that reheat cycle performance is sensitive to the variation of medium pressures and the optimum medium pressures exist for maximizing work output and thermal efficiency, respectively. Reheat cycle is compared to baseline cycle under the same conditions. More significant improvements by reheat are obtained at lower turbine inlet temperatures and larger high cycle pressure. Work output improvement is much higher than thermal efficiency improvement, because extra waste heat is required to reheat CO2. Based on second law analysis, exergy efficiency of reheat cycle is also higher than that of baseline cycle, because more useful work is converted from waste heat. Reheat with two stage expansion has great potential to improve thermal efficiency and especially net work output of a CO2 transcritical power cycle using a low-grade heat source.

Development of a particle method of characteristics (PMOC) for one-dimensional shock waves

NASA Astrophysics Data System (ADS)

Hwang, Y.-H.

2018-03-01

In the present study, a particle method of characteristics is put forward to simulate the evolution of one-dimensional shock waves in barotropic gaseous, closed-conduit, open-channel, and two-phase flows. All these flow phenomena can be described with the same set of governing equations. The proposed scheme is established based on the characteristic equations and formulated by assigning the computational particles to move along the characteristic curves. Both the right- and left-running characteristics are traced and represented by their associated computational particles. It inherits the computational merits from the conventional method of characteristics (MOC) and moving particle method, but without their individual deficiencies. In addition, special particles with dual states deduced to the enforcement of the Rankine-Hugoniot relation are deliberately imposed to emulate the shock structure. Numerical tests are carried out by solving some benchmark problems, and the computational results are compared with available analytical solutions. From the derivation procedure and obtained computational results, it is concluded that the proposed PMOC will be a useful tool to replicate one-dimensional shock waves.

Solution of the equations for one-dimensional, two-phase, immiscible flow by geometric methods

NASA Astrophysics Data System (ADS)

Boronin, Ivan; Shevlyakov, Andrey

2018-03-01

Buckley-Leverett equations describe non viscous, immiscible, two-phase filtration, which is often of interest in modelling of oil production. For many parameters and initial conditions, the solutions of these equations exhibit non-smooth behaviour, namely discontinuities in form of shock waves. In this paper we obtain a novel method for the solution of Buckley-Leverett equations, which is based on geometry of differential equations. This method is fast, accurate, stable, and describes non-smooth phenomena. The main idea of the method is that classic discontinuous solutions correspond to the continuous surfaces in the space of jets - the so-called multi-valued solutions (Bocharov et al., Symmetries and conservation laws for differential equations of mathematical physics. American Mathematical Society, Providence, 1998). A mapping of multi-valued solutions from the jet space onto the plane of the independent variables is constructed. This mapping is not one-to-one, and its singular points form a curve on the plane of the independent variables, which is called the caustic. The real shock occurs at the points close to the caustic and is determined by the Rankine-Hugoniot conditions.

Higher dose intra-arterial milrinone and intra-arterial combined milrinone-nimodipine infusion as a rescue therapy for refractory cerebral vasospasm.

PubMed

Duman, Enes; Karakoç, Fatma; Pinar, H Ulas; Dogan, Rafi; Fırat, Ali; Yıldırım, Erkan

2017-12-01

Background Cerebral vasospasm (CV) is a major cause of delayed morbidity and mortality in patients with subarachnoid hemorrhage (SAH). Various cerebral protectants have been tested in patients with aneurysmal SAH. We aimed to research the success rate of treatment of CV via intra-arterial milrinone injection and aggressive pharmacological therapy for refractory CV. Methods A total of 25 consecutive patients who received intra-arterial milrinone and nimodipine treatment for CV following SAH between 2014 and 2017 were included in the study. Patients who underwent surgical clipping were excluded. Refractory vasospasm was defined as patients with CV refractory to therapies requiring ≥3 endovascular interventions. Overall, six patients had refractory CV. Long-term neurological outcome was assessed 6-18 months after SAH using a modified Rankin score and Barthel index. Results The median modified Rankin scores were 1 (min: 0, max: 3) and Barthel index scores were 85 (min: 70, max: 100) From each vasospastic territory maximal 10-16 mg milrinone was given to patients; a maximum of 24 mg milrinone was given to each patient in a session and a maximum of 42 mg milrinone was given to a patient in a day. Both milrinone and nimodipine were given to three patients. There was a large vessel diameter increase after milrinone and nimodipine injections. No patient died due to CV; only one patient had motor dysfunction on the right lower extremity. Conclusion Higher doses of milrinone can be used effectively to control refractory CV. For exceptional patients with refractory CV, high dose intra-arterial nimodipine and milrinone infusion can be used as a rescue therapy.

Endovascular treatment outcomes using the Stroke Triage Education, Procedure Standardization, and Technology (STEPS-T) program.

PubMed

Hassan, Ameer E; Sanchez, Christina; Johnson, Angela N

2018-02-01

Background "Door to treatment" time affects outcomes of acute ischemic stroke (AIS) patients undergoing endovascular treatment (EVT). However, the correlation between staff education and accessible technology with stroke outcomes has not been demonstrated. Objective The objective of this paper is to demonstrate the five-year impact of the Stroke Triage Education, Procedure Standardization, and Technology (STEPS-T) program on time-to-treat and clinical outcomes. Methods The study analyzed a prospectively maintained database of AIS patients who benefited from EVT through implementation of STEPS-T. Demographics, clinical characteristics, and modified Rankin Score at three months were analyzed. Thrombolysis in Cerebral Infarction (TICI) scale was used to grade pre- and post-procedure angiographic recanalization. Using electronic hemodynamic recording, stepwise workflow times were collected for door time (T D ), entering angiography suite (T A ), groin puncture (T G ), first DSA (T DSA ), microcatheter placement (T M ), and final recanalization (T R ). Median intervention time (T A to T R ) and recanalization time (T G to T R ) were compared through Year 1 to Year 5. Results A total of 230 individuals (age 74 ± 12, between 30 to 95) were enrolled. Median intervention and recanalization times were significantly reduced, from 121 minutes to 52 minutes and from 83 minutes to 36 minutes respectively from Year 1 to Year 5, ( p < 0.001). Across the study period, annual recruitment went up from 12 to 66 patients, and modified Rankin Score between 0 and 2 increased from 36% to 59% ( p = 0.024). Conclusions STEPS-T improved time-to-treat in patients undergoing mechanical thrombectomy for AIS. During the observation period, clinical outcomes significantly improved.

Solar-powered air-conditioning

NASA Technical Reports Server (NTRS)

Clark, D. C.; Rousseau, J.

1977-01-01

Report focuses on recent study on development of solar-powered residential air conditioners and is based on selected literature through 1975. Its purposes are to characterize thermal and mechanical systems that might be useful in development of Rankine-cycle approach to solar cooling and assessment of a Lithium Bromide/Water absorption cycle system.

Nuclear Power Systems for Manned Mission to Mars

DTIC Science & Technology

2004-12-01

Brayton Cycle ..........................................................................30 c. Stirling Cycle ...specific mass as the power level increases. This graph also shows the upward scalability of Brayton and Rankine cycles , predicting that higher...Orbit, 1985), 79. 47Joseph A. Angelo, Jr. and David Buden, Space Nuclear Power, (Malabar, Florida: Orbit, 1985), 80. 30 b. Brayton Cycle

Liquid-metal binary cycles for stationary power

NASA Technical Reports Server (NTRS)

Gutstein, M.; Furman, E. R.; Kaplan, G. M.

1975-01-01

The use of topping cycles to increase electric power plant efficiency is discussed, with particular attention to mercury and alkali metal Rankine cycle systems that could be considered for topping cycle applications. An overview of this technology, possible system applications, the required development, and possible problem areas is presented.

An Examination of Campus Climate for LGBTQ Community College Students

ERIC Educational Resources Information Center

Garvey, Jason C.; Taylor, Jason L.; Rankin, Susan

2015-01-01

This study examines campus climate for lesbian, gay, bisexual, transgender, and queer (LGBTQ) undergraduate students at community colleges. Data for the study originates from Rankin, Blumenfeld, Weber, and Frazer's (2010) "State of Higher Education for LGBT People." We analyzed both quantitative data generated from closed-ended…

75 FR 27768 - Current Connection, LLC; Notice of Preliminary Permit Application Accepted for Filing and...

Federal Register 2010, 2011, 2012, 2013, 2014

2010-05-18

..., Motions To Intervene, and Competing Applications May 11, 2010. On March 30, 2010, Current Connection, LLC.... Applicant Contact: Timothy D. Smith, CEO, Current Connection, LLC, 1300 Rankin Drive, Troy, MI 48083; phone... DEPARTMENT OF ENERGY Federal Energy Regulatory Commission [Project No. 13694-000] Current...

Careers in the Classics

ERIC Educational Resources Information Center

Lum, Lydia

2005-01-01

America's few Black classics professors have overcome contempt and criticism to contribute a unique perspective to the study of the ancient world. Dr. Patrice Rankine, an associate professor from Purdue University, has grown used to the irony. As one of the few Black classicists teaching at an American university, he has drawn plenty of skepticism…

Community College Retention and Access Issues: A View from the Field

ERIC Educational Resources Information Center

Rankin, Kristie R.; Katsinas, Stephen G.; Hardy, David E.

2011-01-01

Drawing on Rankin's 2008 study and literature on retention and community colleges, this study presents perceptions of community college Chief Executive Officers (CEOs) and Chief Academic Officers (CAOs) in relation to issues affecting retention and access. Childcare, transportation, and funding concerns are examined. (Contains 2 tables.)

Culturally Relevant Pedagogical Practice among White College Faculty: A Narrative Study

ERIC Educational Resources Information Center

Miller, Susan F.

2013-01-01

Faculty contribute to the campus racial climate for all students, but particularly for students of color, and play a significant role in shaping intellectual, social, and behavioral standards through their pedagogical practice (Hurtado, Milem, Clayton-Petersen, & Allen, 1998; Solózano, Ceja, & Yosso, 2000; Rankin & Reason, 2005).…

77 FR 20438 - Independent Spent Fuel Storage Installation, Virginia Electric and Power Company: North Anna...

Federal Register 2010, 2011, 2012, 2013, 2014

2012-04-04

... Units 1 and 2 AGENCY: Nuclear Regulatory Commission. ACTION: Issuance of an environmental assessment and finding of no significant impact. FOR FURTHER INFORMATION CONTACT: Jennie Rankin, Project Manager..., located in Louisa County, Virginia. II. Environmental Assessment (EA) Identification of Proposed Action...

77 FR 20440 - Independent Spent Fuel Storage Installation, Virginia Electric and Power Company, Surry Power...

Federal Register 2010, 2011, 2012, 2013, 2014

2012-04-04

... and 2 AGENCY: Nuclear Regulatory Commission. ACTION: Issuance of an environmental assessment and finding of no significant impact. FOR FURTHER INFORMATION CONTACT: Jennie Rankin, Project Manager... reactors, Surry Power Station Units 1 and 2, located in Surry County, Virginia. II. Environmental...

Engaging & Challenging Gifted Students: The Five OEs

ERIC Educational Resources Information Center

Rankin, Jenny Grant

2017-01-01

Though nearly 5 million students can be characterized as gifted and talented in the United States, many exceptional learners "fly under the radar." Because they are not appropriately challenged in the general classroom, they never meet their full potential--in school or in life. Author Jenny Grant Rankin equips general classroom teachers…

DOE New Technology. Sharing New Frontiers.

DTIC Science & Technology

1992-11-01

Simpson Mr. Philip W. Krey Stanford Linear Accelerator Center U.S. Department of Energy P.O. Box 4349 Environmental Measurements Laboratory Stanford, CA...Washington, DC (United netic field controller. Kotler , D.K.; Rankin, R.A.; Morgan, States). USA Patent 5,026,154/A/. 25 Jun 1991. Filed date J.P. To

Concentrating Solar Power Projects - Kathu Solar Park | Concentrating Solar

Science.gov Websites

): Eskom Plant Configuration Solar Field Heat-Transfer Fluid Type: Thermal oil Solar-Field Inlet Temp: 293Â (Net): 100.0 MW Output Type: Steam Rankine Thermal Storage Storage Type: 2-tank indirect Storage Capacity: 4.5 hours Thermal Storage Description: Molten salt

Concentrating Solar Power Projects - National Solar Thermal Power Facility

Science.gov Websites

| Concentrating Solar Power | NREL National Solar Thermal Power Facility Status Date: February 13, 2014 Project Overview Project Name: National Solar Thermal Power Facility Country: India Location Capacity (Net): 1.0 MW Output Type: Steam Rankine Thermal Storage Storage Type: None

40 CFR 1036.615 - Engines with Rankine cycle waste heat recovery and hybrid powertrains.

Code of Federal Regulations, 2013 CFR

2013-07-01

... 1065 or with the post-transmission test procedures in 40 CFR 1037.550. Pre-transmission hybrid... post-transmission hybrid powertrains: (1) Pre-transmission hybrid powertrains are those engine systems... or using the post-transmission test procedures in 40 CFR 1037.550. (2) Post-transmission hybrid...

Making the Grade? Classroom Climate for LGBTQ Students across Gender Conformity

ERIC Educational Resources Information Center

Garvey, Jason C.; Rankin, Susan R.

2015-01-01

Using data from the "2010 State of Higher Education for LGBT People" (Rankin, Weber, Blumenfeld, & Frazer), this study examines campus climate perceptions for LGBTQ undergraduate students across gender conformity and the extent to which relevant variables influence perceptions of classroom climate. Findings reveal more positive…

Structure-preserving operators for thermal-nonequilibrium hydrodynamics

NASA Astrophysics Data System (ADS)

Shiroto, Takashi; Kawai, Soshi; Ohnishi, Naofumi

2018-07-01

Radiation hydrodynamics simulations based on a single fluid two-temperature model may violate the law of energy conservation, because the governing equations are expressed in a nonconservative formulation. In this study, we maintain the important physical requirements by employing a strategy based on the key concept that mathematical structures associated with conservative and nonconservative equations are preserved, even at the discrete level. To this end, we discretize the conservation laws and transform them using exact algebraic operations. The proposed scheme maintains global conservation errors within the round-off level. In addition, a numerical experiment concerning the shock tube problem suggests that the proposed scheme agrees well with the jump conditions at the discontinuities regulated by the Rankine-Hugoniot relationship. The generalized derivation allows us to employ arbitrary central difference, artificial dissipation, and Runge-Kutta methods.

40 CFR 1036.615 - Engines with Rankine cycle waste heat recovery and hybrid powertrains.

Code of Federal Regulations, 2012 CFR

2012-07-01

... vehicle wheels. These powertrains are tested using the hybrid engine test procedures of 40 CFR part 1065 or using the post-transmission test procedures in 40 CFR 1037.550. (2) Post-transmission hybrid... post-transmission hybrid powertrains: (1) Pre-transmission hybrid powertrains are those engine systems...

40 CFR 1036.615 - Engines with Rankine cycle waste heat recovery and hybrid powertrains.

Code of Federal Regulations, 2014 CFR

2014-07-01

... energy recovery systems. (a) Pre-transmission hybrid powertrains. Test pre-transmission hybrid powertrains with the hybrid engine test procedures of 40 CFR part 1065 or with the post-transmission test... tested using the hybrid engine test procedures of 40 CFR part 1065 or using the post-transmission test...

The 50-horsepower solar-powered irrigation facility located near Gila Bend, Arizona

NASA Astrophysics Data System (ADS)

Smith, W. A.; Alexander, G.; Busch, D. F.

1980-05-01

The 50 horsepower solar powered irrigation facility near Gila Bend, Arizona which includes a Rankine cycle demonstrates the technical feasibility of solar powered pumping. The design of a facility specifically for the irrigation farmer using the technology that has been developed over the last four years is proposed.

Out in the Classroom: Transgender Student Experiences at a Large Public University

ERIC Educational Resources Information Center

Pryor, Jonathan T.

2015-01-01

Faculty and peer interactions are 2 of the most important relationships for college students to foster (Astin, 1993). Transgender college students have an increasing visible presence on college campuses (Pusch, 2005), yet limited research exists on their experiences and struggles in the classroom environment (Garvey & Rankin, 2015; Renn,…

Recommendations from the Field: Creating an LGBTQ Learning Community

ERIC Educational Resources Information Center

Jaekel, Kathryn S.

2015-01-01

This article details the creation of a lesbian, gay, bisexual, transgender, and queer (LGBTQ) learning community. Created because of research that indicates chilly campus climates (Rankin, 2005), as well as particular needs of LGBTQ students in the classroom, this learning community focused upon LGBTQ topics in and out of the classroom. While…

The 50-horsepower solar-powered irrigation facility located near Gila Bend, Arizona

NASA Technical Reports Server (NTRS)

Smith, W. A.; Alexander, G.; Busch, D. F.

1980-01-01

The 50 horsepower solar powered irrigation facility near Gila Bend, Arizona which includes a Rankine cycle demonstrates the technical feasibility of solar powered pumping. The design of a facility specifically for the irrigation farmer using the technology that has been developed over the last four years is proposed.

Differing Perceptions: How Students of Color and White Students Perceive Campus Climate for Underrepresented Groups

ERIC Educational Resources Information Center

Rankin, Susan R.; Reason, Robert D.

2005-01-01

Using a campus climate assessment instrument developed by Rankin (1998), we surveyed students (n = 7,347) from 10 campuses to explore whether students from different racial groups experienced their campus climates differently. Students of color experienced harassment at higher rates than Caucasian students, although female White students reported…

75 FR 69397 - Minnkota Power Cooperative, Inc.: Notice of Availability of an Environmental Assessment

Federal Register 2010, 2011, 2012, 2013, 2014

2010-11-12

... Environmental Assessment (EA) to meet its responsibilities under the National Environmental Policy Act (NEPA...: To obtain copies of the EA or for further information, contact: Mr. Dennis Rankin, Environmental...-1571, fax: (202) 690-0649, or e-mail: [email protected] . A copy of the EA will be available...

The Temperance Movement and Social Work

ERIC Educational Resources Information Center

Murdach, Allison D.

2009-01-01

This article examines a forgotten episode in social work history: the involvement of the profession in the temperance movement in the late 19th and early 20th centuries. Though some notable social workers such as Jane Addams, Robert A. Woods, and Representative Jeannette Rankin (the first woman elected to the U.S. Congress), championed the…

College Students' Experiences and Perceptions of Harassment on Campus: An Exploration of Gender Differences

ERIC Educational Resources Information Center

Reason, Robert D.; Rankin, Susan R.

2006-01-01

Using a campus climate assessment instrument developed by Rankin (1998), we surveyed students (N = 7,347) from 10 campuses to explore the different experiences with harassment and campus climates reported by men and women. Both men and women reported experiencing harassment, although women experienced harassment at statistically significantly…

Restricted and Adaptive Masculine Gender Performance in White Gay College Men

ERIC Educational Resources Information Center

Anderson-Martinez, Richard; Vianden, Jörg

2014-01-01

This article presents the results of a qualitative exploration of the performance of masculine gender identities in six gay male students enrolled at a master's comprehensive public institution in the Midwest. This article builds on the work of Laker and Davis (2011) and Rankin (2005). The findings indicate participants adapted their gender…

How Does the Economic Crisis Affect the Psychological Well-Being? Comparing College Students and Employees

ERIC Educational Resources Information Center

Wetzel, Kathrin; Mertens, Anne; Röbken, Heinke

2012-01-01

Little is known about differences in the impact of economic stress on students as compared to persons holding secure job positions. Besides the macroeconomic effects, an economic downturn can also affect individual's physical health and psychological well-being (Aytaç & Rankin, 2009). Prior research showed that socio-demographic…

Exergoeconomic analysis and optimization of an evaporator for a binary mixture of fluids in an organic Rankine cycle

NASA Astrophysics Data System (ADS)

Li, You-Rong; Du, Mei-Tang; Wang, Jian-Ning

2012-12-01

This paper focuses on the research of an evaporator with a binary mixture of organic working fluids in the organic Rankine cycle. Exergoeconomic analysis and performance optimization were performed based on the first and second laws of thermodynamics, and the exergoeconomic theory. The annual total cost per unit heat transfer rate was introduced as the objective function. In this model, the exergy loss cost caused by the heat transfer irreversibility and the capital cost were taken into account; however, the exergy loss due to the frictional pressure drops, heat dissipation to surroundings, and the flow imbalance were neglected. The variation laws of the annual total cost with respect to the number of transfer units and the temperature ratios were presented. Optimal design parameters that minimize the objective function had been obtained, and the effects of some important dimensionless parameters on the optimal performances had also been discussed for three types of evaporator flow arrangements. In addition, optimal design parameters of evaporators were compared with those of condensers.

Megawatt Class Nuclear Space Power Systems (MCNSPS) conceptual design and evaluation report. Volume 1: Objectives, summary results and introduction

NASA Technical Reports Server (NTRS)

Wetch, J. R.

1988-01-01

The objective was to determine which reactor, conversion, and radiator technologies would best fulfill future Megawatt Class Nuclear Space Power System Requirements. Specifically, the requirement was 10 megawatts for 5 years of full power operation and 10 years systems life on orbit. A variety of liquid metal and gas cooled reactors, static and dynamic conversion systems, and passive and dynamic radiators were considered. Four concepts were selected for more detailed study. The concepts are: a gas cooled reactor with closed cycle Brayton turbine-alternator conversion with heat pipe and pumped tube-fin heat rejection; a lithium cooled reactor with a free piston Stirling engine-linear alternator and a pumped tube-fin radiator; a lithium cooled reactor with potassium Rankine turbine-alternator and heat pipe radiator; and a lithium cooled incore thermionic static conversion reactor with a heat pipe radiator. The systems recommended for further development to meet a 10 megawatt long life requirement are the lithium cooled reactor with the K-Rankine conversion and heat pipe radiator, and the lithium cooled incore thermionic reactor with heat pipe radiator.

Fully Endoscopic Freehand Evacuation of Spontaneous Supratentorial Intraparenchymal Hemorrhage.

PubMed

Angileri, Filippo Flavio; Esposito, Felice; Priola, Stefano Maria; Raffa, Giovanni; Marino, Daniele; Abbritti, Rosaria Viola; Giusa, Maria; Germanò, Antonino; Tomasello, Francesco

2016-10-01

A modification of other reported endoscopic techniques for intracerebral clot evacuation is described and illustrated. From January 2014 to December 2014, we operated on 6 patients harboring a spontaneous supratentorial intracerebral hemorrhage using a fully endoscopic freehand technique. Clinical chart and surgical videos were analyzed. Volumetric evaluation of the clot preoperatively and the residual hematoma postoperatively was performed. Clinical outcome was measured using the modified Rankin Scale and Glasgow Outcome Scale. The mean operative time was 96 minutes (range, 72-125 minutes). Clot evacuation was >90% in all patients. No patient experienced rebleeding after surgery. Two patients died. The Glasgow Outcome Scale score at 6 months was 4 in 2 patients, 3 in 2 patients, and 1 (death) in 2 patients. The modified Rankin Scale score at 6 months was 6 (death) in 2 patients, 4 in 2 patients, 3 in 1 patient and 2 in 1 patient. The proposed minimally invasive technique allows a good rate of hematoma evacuation and intraoperative bleeding control. Further studies in large series are needed to confirm the role of this freehand endoscopic technique. Copyright © 2016 Elsevier Inc. All rights reserved.

Recent trends in the development of heat exchangers for geothermal systems

NASA Astrophysics Data System (ADS)

Franco, A.; Vaccaro, M.

2017-11-01

The potential use of geothermal resources has been a remarkable driver for market players and companies operating in the field of geothermal energy conversion. For this reason, medium to low temperature geothermal resources have been the object of recent rise in consideration, with strong reference to the perspectives of development of Organic Rankine Cycle (ORC) technology. The main components of geothermal plants based on ORC cycle are surely the heat exchangers. A lot of different heat exchangers are required for the operation of ORC plants. Among those it is surely of major importance the Recovery Heat Exchanger (RHE, typically an evaporator), in which the operating fluid is evaporated. Also the Recuperator, in regenerative Organic Rankine Cycle, is of major interest in technology. Another important application of the heat exchangers is connected to the condensation, according to the possibility of liquid or air cooling media availability. The paper analyzes the importance of heat exchangers sizing and the connection with the operation of ORC power plants putting in evidence the real element of innovation: the consideration of the heat exchangers as central element for the optimum design of ORC systems.

Analysis and optimization of three main organic Rankine cycle configurations using a set of working fluids with different thermodynamic behaviors

NASA Astrophysics Data System (ADS)

Hamdi, Basma; Mabrouk, Mohamed Tahar; Kairouani, Lakdar; Kheiri, Abdelhamid

2017-06-01

Different configurations of organic Rankine cycle (ORC) systems are potential thermodynamic concepts for power generation from low grade heat. The aim of this work is to investigate and optimize the performances of the three main ORC systems configurations: basic ORC, ORC with internal heat exchange (IHE) and regenerative ORC. The evaluation for those configurations was performed using seven working fluids with typical different thermodynamic behaviours (R245fa, R601a, R600a, R227ea, R134a, R1234ze and R1234yf). The optimization has been performed using a genetic algorithm under a comprehensive set of operative parameters such as the fluid evaporating temperature, the fraction of flow rate or the pressure at the steam extracting point in the turbine. Results show that there is no general best ORC configuration for all those fluids. However, there is a suitable configuration for each fluid. Contribution to the topical issue "Materials for Energy harvesting, conversion and storage II (ICOME 2016)", edited by Jean-Michel Nunzi, Rachid Bennacer and Mohammed El Ganaoui

A 15kWe (nominal) solar thermal electric power conversion concept definition study: Steam Rankine reheat reciprocator system

NASA Technical Reports Server (NTRS)

Fuller, H.; Demler, R.; Poulin, E.; Dantowitz, P.

1979-01-01

An evaluation was made of the potential of a steam Rankine reheat reciprocator engine to operate at high efficiency in a point-focusing distributed receiver solar thermal-electric power system. The scope of the study included the engine system and electric generator; not included was the solar collector/mirror or the steam generator/receiver. A parametric analysis of steam conditions was completed leading to the selection of 973 K 12.1 MPa as the steam temperature/pressure for a conceptual design. A conceptual design was completed for a two cylinder/ opposed engine operating at 1800 rpm directly coupled to a commercially available induction generator. A unique part of the expander design is the use of carbon/graphite piston rings to eliminate the need for using oil as an upper cylinder lubricant. The evaluation included a system weight estimate of 230 kg at the mirror focal point with the condenser mounted separately on the ground. The estimated cost of the overall system is $1932 or $90/kW for the maximum 26 kW output.

Optimal design of solid oxide fuel cell, ammonia-water single effect absorption cycle and Rankine steam cycle hybrid system

NASA Astrophysics Data System (ADS)

Mehrpooya, Mehdi; Dehghani, Hossein; Ali Moosavian, S. M.

2016-02-01

A combined system containing solid oxide fuel cell-gas turbine power plant, Rankine steam cycle and ammonia-water absorption refrigeration system is introduced and analyzed. In this process, power, heat and cooling are produced. Energy and exergy analyses along with the economic factors are used to distinguish optimum operating point of the system. The developed electrochemical model of the fuel cell is validated with experimental results. Thermodynamic package and main parameters of the absorption refrigeration system are validated. The power output of the system is 500 kW. An optimization problem is defined in order to finding the optimal operating point. Decision variables are current density, temperature of the exhaust gases from the boiler, steam turbine pressure (high and medium), generator temperature and consumed cooling water. Results indicate that electrical efficiency of the combined system is 62.4% (LHV). Produced refrigeration (at -10 °C) and heat recovery are 101 kW and 22.1 kW respectively. Investment cost for the combined system (without absorption cycle) is about 2917 kW-1.

Solitaire™ with the Intention for Thrombectomy as Primary Endovascular Treatment for Acute Ischemic Stroke (SWIFT PRIME) trial: protocol for a randomized, controlled, multicenter study comparing the Solitaire revascularization device with IV tPA with IV tPA alone in acute ischemic stroke.

PubMed

Saver, Jeffrey L; Goyal, Mayank; Bonafe, Alain; Diener, Hans-Christoph; Levy, Elad I; Pereira, Vitor M; Albers, Gregory W; Cognard, Christophe; Cohen, David J; Hacke, Werner; Jansen, Olav; Jovin, Tudor G; Mattle, Heinrich P; Nogueira, Raul G; Siddiqui, Adnan H; Yavagal, Dileep R; Devlin, Thomas G; Lopes, Demetrius K; Reddy, Vivek; du Mesnil de Rochemont, Richard; Jahan, Reza

2015-04-01

Early reperfusion in patients experiencing acute ischemic stroke is critical, especially for patients with large vessel occlusion who have poor prognosis without revascularization. Solitaire™ stent retriever devices have been shown to immediately restore vascular perfusion safely, rapidly, and effectively in acute ischemic stroke patients with large vessel occlusions. The aim of the study was to demonstrate that, among patients with large vessel, anterior circulation occlusion who have received intravenous tissue plasminogen activator, treatment with Solitaire revascularization devices reduces degree of disability 3 months post stroke. The study is a global multicenter, two-arm, prospective, randomized, open, blinded end-point trial comparing functional outcomes in acute ischemic stroke patients who are treated with either intravenous tissue plasminogen activator alone or intravenous tissue plasminogen activator in combination with the Solitaire device. Up to 833 patients will be enrolled. Patients who have received intravenous tissue plasminogen activator are randomized to either continue with intravenous tissue plasminogen activator alone or additionally proceed to neurothrombectomy using the Solitaire device within six-hours of symptom onset. The primary end-point is 90-day global disability, assessed with the modified Rankin Scale (mRS). Secondary outcomes include mortality at 90 days, functional independence (mRS ≤ 2) at 90 days, change in National Institutes of Health Stroke Scale at 27 h, reperfusion at 27 h, and thrombolysis in cerebral infarction 2b/3 flow at the end of the procedure. Statistical analysis will be conducted using simultaneous success criteria on the overall distribution of modified Rankin Scale (Rankin shift) and proportions of subjects achieving functional independence (mRS 0-2). © 2015 The Authors. International Journal of Stroke published by John Wiley & Sons Ltd on behalf of World Stroke Organization.

Efficacy and Safety of Individualized Coaching After Stroke: the LAST Study (Life After Stroke): A Pragmatic Randomized Controlled Trial.

PubMed

Askim, Torunn; Langhammer, Birgitta; Ihle-Hansen, Hege; Gunnes, Mari; Lydersen, Stian; Indredavik, Bent

2018-02-01

The evidence for interventions to prevent functional decline in the long term after stroke is lacking. The aim of this trial was to evaluate the efficacy and safety of an 18-month follow-up program of individualized regular coaching on physical activity and exercise. This was a multicentre, pragmatic, single-blinded, randomized controlled trial. Adults (age ≥18 years) with first-ever or recurrent stroke, community dwelling, with modified Rankin Scale <5, and no serious comorbidities were included 10 to 16 weeks poststroke. The intervention group received individualized regular coaching on physical activity and exercise every month for 18 consecutive months. The control group received standard care. Primary outcome was the Motor Assessment Scale at end of intervention (18-month follow-up). Secondary measures were Barthel index, modified Rankin Scale, item 14 from Berg Balance Scale, Timed Up and Go test, gait speed, 6-minute walk test, and Stroke Impact Scale. Other outcomes were adverse events and compliance to the intervention assessed by training diaries and the International Physical Activity Questionnaire. Three hundred and eighty consenting participants were randomly assigned to individualized coaching (n=186) or standard care (n=194). The mean estimated difference on Motor Assessment Scale in favor of control group was -0.70 points (95% confidence interval, -2.80, 1.39), P =0.512. There were no differences between the groups on Barthel index, modified Rankin Scale, or Berg Balance Scale. The frequency of adverse events was low in both groups. Results from International Physical Activity Questionnaire and training diaries showed increased activity levels but low intensity of the exercise in the intervention group. The regular individualized coaching did not improve maintenance of motor function or the secondary outcomes compared with standard care. The intervention should be regarded as safe. Despite the neutral results, the health costs related to the intervention should be investigated. URL: https://www.clinicaltrials.gov. Unique identifier: NCT01467206. © 2017 American Heart Association, Inc.

Preliminary analysis of compound systems based on high temperature fuel cell, gas turbine and Organic Rankine Cycle

NASA Astrophysics Data System (ADS)

Sánchez, D.; Muñoz de Escalona, J. M.; Monje, B.; Chacartegui, R.; Sánchez, T.

This article presents a novel proposal for complex hybrid systems comprising high temperature fuel cells and thermal engines. In this case, the system is composed by a molten carbonate fuel cell with cascaded hot air turbine and Organic Rankine Cycle (ORC), a layout that is based on subsequent waste heat recovery for additional power production. The work will credit that it is possible to achieve 60% efficiency even if the fuel cell operates at atmospheric pressure. The first part of the analysis focuses on selecting the working fluid of the Organic Rankine Cycle. After a thermodynamic optimisation, toluene turns out to be the most efficient fluid in terms of cycle performance. However, it is also detected that the performance of the heat recovery vapour generator is equally important, what makes R245fa be the most interesting fluid due to its balanced thermal and HRVG efficiencies that yield the highest global bottoming cycle efficiency. When this fluid is employed in the compound system, conservative operating conditions permit achieving 60% global system efficiency, therefore accomplishing the initial objective set up in the work. A simultaneous optimisation of gas turbine (pressure ratio) and ORC (live vapour pressure) is then presented, to check if the previous results are improved or if the fluid of choice must be replaced. Eventually, even if system performance improves for some fluids, it is concluded that (i) R245fa is the most efficient fluid and (ii) the operating conditions considered in the previous analysis are still valid. The work concludes with an assessment about safety-related aspects of using hydrocarbons in the system. Flammability is studied, showing that R245fa is the most interesting fluid also in this regard due to its inert behaviour, as opposed to the other fluids under consideration all of which are highly flammable.

A randomized trial of intraarterial treatment for acute ischemic stroke.

PubMed

Berkhemer, Olvert A; Fransen, Puck S S; Beumer, Debbie; van den Berg, Lucie A; Lingsma, Hester F; Yoo, Albert J; Schonewille, Wouter J; Vos, Jan Albert; Nederkoorn, Paul J; Wermer, Marieke J H; van Walderveen, Marianne A A; Staals, Julie; Hofmeijer, Jeannette; van Oostayen, Jacques A; Lycklama à Nijeholt, Geert J; Boiten, Jelis; Brouwer, Patrick A; Emmer, Bart J; de Bruijn, Sebastiaan F; van Dijk, Lukas C; Kappelle, L Jaap; Lo, Rob H; van Dijk, Ewoud J; de Vries, Joost; de Kort, Paul L M; van Rooij, Willem Jan J; van den Berg, Jan S P; van Hasselt, Boudewijn A A M; Aerden, Leo A M; Dallinga, René J; Visser, Marieke C; Bot, Joseph C J; Vroomen, Patrick C; Eshghi, Omid; Schreuder, Tobien H C M L; Heijboer, Roel J J; Keizer, Koos; Tielbeek, Alexander V; den Hertog, Heleen M; Gerrits, Dick G; van den Berg-Vos, Renske M; Karas, Giorgos B; Steyerberg, Ewout W; Flach, H Zwenneke; Marquering, Henk A; Sprengers, Marieke E S; Jenniskens, Sjoerd F M; Beenen, Ludo F M; van den Berg, René; Koudstaal, Peter J; van Zwam, Wim H; Roos, Yvo B W E M; van der Lugt, Aad; van Oostenbrugge, Robert J; Majoie, Charles B L M; Dippel, Diederik W J

2015-01-01

In patients with acute ischemic stroke caused by a proximal intracranial arterial occlusion, intraarterial treatment is highly effective for emergency revascularization. However, proof of a beneficial effect on functional outcome is lacking. We randomly assigned eligible patients to either intraarterial treatment plus usual care or usual care alone. Eligible patients had a proximal arterial occlusion in the anterior cerebral circulation that was confirmed on vessel imaging and that could be treated intraarterially within 6 hours after symptom onset. The primary outcome was the modified Rankin scale score at 90 days; this categorical scale measures functional outcome, with scores ranging from 0 (no symptoms) to 6 (death). The treatment effect was estimated with ordinal logistic regression as a common odds ratio, adjusted for prespecified prognostic factors. The adjusted common odds ratio measured the likelihood that intraarterial treatment would lead to lower modified Rankin scores, as compared with usual care alone (shift analysis). We enrolled 500 patients at 16 medical centers in The Netherlands (233 assigned to intraarterial treatment and 267 to usual care alone). The mean age was 65 years (range, 23 to 96), and 445 patients (89.0%) were treated with intravenous alteplase before randomization. Retrievable stents were used in 190 of the 233 patients (81.5%) assigned to intraarterial treatment. The adjusted common odds ratio was 1.67 (95% confidence interval [CI], 1.21 to 2.30). There was an absolute difference of 13.5 percentage points (95% CI, 5.9 to 21.2) in the rate of functional independence (modified Rankin score, 0 to 2) in favor of the intervention (32.6% vs. 19.1%). There were no significant differences in mortality or the occurrence of symptomatic intracerebral hemorrhage. In patients with acute ischemic stroke caused by a proximal intracranial occlusion of the anterior circulation, intraarterial treatment administered within 6 hours after stroke onset was effective and safe. (Funded by the Dutch Heart Foundation and others; MR CLEAN Netherlands Trial Registry number, NTR1804, and Current Controlled Trials number, ISRCTN10888758.).

Thrombolytic-Related Asymptomatic Hemorrhagic Transformation Does Not Deteriorate Clinical Outcome: Data from TIMS in China.

PubMed

Jia, Weihua; Liao, Xiaoling; Pan, Yuesong; Wang, Yilong; Cui, Tao; Zhou, Lichun; Wang, Yongjun

2015-01-01

It has been unclear whether thrombolytic-related asymptomatic hemorrhagic transformation (AHT) affects the clinical outcome. To answer this question, we examined whether thrombolytic-related AHT affect short-term and long-term clinical outcome. All data were collected from the Thrombolysis Implementation and Monitor of Acute Ischemic Stroke in China (TIMS-China) registry. The patients were diagnosed as having AHT group and non- hemorrhagic transformation (HT) group based on clinical and imaging data. The patients with symptomatic hemorrhagic transformation were excluded from this study. Thrombolytic-related AHT was defined according to European-Australasian Acute Stroke Study (ECASS) II criteria. 90-day functional outcome, 7-day National Institutes of Health Stroke Scale (NIHSS) score, 7-day and 90-day mortalities were compared between two groups. Logistic regression analysis was used to evaluate the effects of AHT on a short-term and long-term clinical outcome. 904 of all 1440 patients in TIMS-China registry were enrolled. 89 (9.6%) patients presented with AHT after thrombolysis within 24-36 h. These patients with AHT were more likely to be elder age, cardioembolic subtype, and to have higher National Institutes of Health Stroke Scale score before thrombolysis than patients without AHT. No significant difference was found on the odds of 7-day (95% CI:0.692 (0.218-2.195), (P = 0.532) or 90-day mortalities (95% CI:0.548 (0.237-1.268), P = 0.160) and modified Rankin Score(0-1) at 90-day (95% CI:0.798 (0.460-1.386), P = 0.423) or modified Rankin Score(0-2) at 90-day (95% CI:0.732 (0.429-1.253), P = 0.116) or modified Rankin Score(5-6) at 90-day (95% CI:0.375 (0.169-1.830), P = 0.116) between two groups. Thrombolytic-related AHT does not deteriorate short-term and long-term clinical outcome.

Endovascular Therapy Is Effective and Safe for Patients With Severe Ischemic Stroke: Pooled Analysis of Interventional Management of Stroke III and Multicenter Randomized Clinical Trial of Endovascular Therapy for Acute Ischemic Stroke in the Netherlands Data.

PubMed

Broderick, Joseph P; Berkhemer, Olvert A; Palesch, Yuko Y; Dippel, Diederik W J; Foster, Lydia D; Roos, Yvo B W E M; van der Lugt, Aad; Tomsick, Thomas A; Majoie, Charles B L M; van Zwam, Wim H; Demchuk, Andrew M; van Oostenbrugge, Robert J; Khatri, Pooja; Lingsma, Hester F; Hill, Michael D; Roozenbeek, Bob; Jauch, Edward C; Jovin, Tudor G; Yan, Bernard; von Kummer, Rüdiger; Molina, Carlos A; Goyal, Mayank; Schonewille, Wouter J; Mazighi, Mikael; Engelter, Stefan T; Anderson, Craig S; Spilker, Judith; Carrozzella, Janice; Ryckborst, Karla J; Janis, L Scott; Simpson, Kit N

2015-12-01

We assessed the effect of endovascular treatment in acute ischemic stroke patients with severe neurological deficit (National Institutes of Health Stroke Scale score, ≥20) after a prespecified analysis plan. The pooled analysis of the Interventional Management of Stroke III (IMS III) and Multicenter Randomized Clinical Trial of Endovascular Therapy for Acute Ischemic Stroke in the Netherlands (MR CLEAN) trials included participants with an National Institutes of Health Stroke Scale score of ≥20 before intravenous tissue-type plasminogen activator (tPA) treatment (IMS III) or randomization (MR CLEAN) who were treated with intravenous tPA ≤3 hours of stroke onset. Our hypothesis was that participants with severe stroke randomized to endovascular therapy after intravenous tPA would have improved 90-day outcome (distribution of modified Rankin Scale scores), when compared with those who received intravenous tPA alone. Among 342 participants in the pooled analysis (194 from IMS III and 148 from MR CLEAN), an ordinal logistic regression model showed that the endovascular group had superior 90-day outcome compared with the intravenous tPA group (adjusted odds ratio, 1.78; 95% confidence interval, 1.20-2.66). In the logistic regression model of the dichotomous outcome (modified Rankin Scale score, 0-2, or functional independence), the endovascular group had superior outcomes (adjusted odds ratio, 1.97; 95% confidence interval, 1.09-3.56). Functional independence (modified Rankin Scale score, ≤2) at 90 days was 25% in the endovascular group when compared with 14% in the intravenous tPA group. Endovascular therapy after intravenous tPA within 3 hours of symptom onset improves functional outcome at 90 days after severe ischemic stroke. URL: http://www.clinicaltrials.gov. Unique identifier: NCT00359424 (IMS III) and ISRCTN10888758 (MR CLEAN). © 2015 American Heart Association, Inc.

Adopting a Patient-Centered Approach to Primary Outcome Analysis of Acute Stroke Trials Using a Utility-Weighted Modified Rankin Scale.

PubMed

Chaisinanunkul, Napasri; Adeoye, Opeolu; Lewis, Roger J; Grotta, James C; Broderick, Joseph; Jovin, Tudor G; Nogueira, Raul G; Elm, Jordan J; Graves, Todd; Berry, Scott; Lees, Kennedy R; Barreto, Andrew D; Saver, Jeffrey L

2015-08-01

Although the modified Rankin Scale (mRS) is the most commonly used primary end point in acute stroke trials, its power is limited when analyzed in dichotomized fashion and its indication of effect size challenging to interpret when analyzed ordinally. Weighting the 7 Rankin levels by utilities may improve scale interpretability while preserving statistical power. A utility-weighted mRS (UW-mRS) was derived by averaging values from time-tradeoff (patient centered) and person-tradeoff (clinician centered) studies. The UW-mRS, standard ordinal mRS, and dichotomized mRS were applied to 11 trials or meta-analyses of acute stroke treatments, including lytic, endovascular reperfusion, blood pressure moderation, and hemicraniectomy interventions. Utility values were 1.0 for mRS level 0; 0.91 for mRS level 1; 0.76 for mRS level 2; 0.65 for mRS level 3; 0.33 for mRS level 4; 0 for mRS level 5; and 0 for mRS level 6. For trials with unidirectional treatment effects, the UW-mRS paralleled the ordinal mRS and outperformed dichotomous mRS analyses. Both the UW-mRS and the ordinal mRS were statistically significant in 6 of 8 unidirectional effect trials, whereas dichotomous analyses were statistically significant in 2 to 4 of 8. In bidirectional effect trials, both the UW-mRS and ordinal tests captured the divergent treatment effects by showing neutral results, whereas some dichotomized analyses showed positive results. Mean utility differences in trials with statistically significant positive results ranged from 0.026 to 0.249. A UW-mRS performs similar to the standard ordinal mRS in detecting treatment effects in actual stroke trials and ensures the quantitative outcome is a valid reflection of patient-centered benefits. © 2015 American Heart Association, Inc.

Simple, stable and reliable modeling of gas properties of organic working fluids in aerodynamic designs of turbomachinery for ORC and VCC

NASA Astrophysics Data System (ADS)

Kawakubo, T.

2016-05-01

A simple, stable and reliable modeling of the real gas nature of the working fluid is required for the aerodesigns of the turbine in the Organic Rankine Cycle and of the compressor in the Vapor Compression Cycle. Although many modern Computational Fluid Dynamics tools are capable of incorporating real gas models, simulations with such a gas model tend to be more time-consuming than those with a perfect gas model and even can be unstable due to the simulation near the saturation boundary. Thus a perfect gas approximation is still an attractive option to stably and swiftly conduct a design simulation. In this paper, an effective method of the CFD simulation with a perfect gas approximation is discussed. A method of representing the performance of the centrifugal compressor or the radial-inflow turbine by means of each set of non-dimensional performance parameters and translating the fictitious perfect gas result to the actual real gas performance is presented.

Measuring the Optical Performance of Evacuated Receivers via an Outdoor Thermal Transient Test: Preprint

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

Kutscher, C.; Burkholder, F.; Netter, J.

2011-08-01

Modern parabolic trough solar collectors operated at high temperatures to provide the heat input to Rankine steam power cycles employ evacuated receiver tubes along the collector focal line. High performance is achieved via the use of a selective surface with a high absorptance for incoming short-wave solar radiation and a low emittance for outgoing long-wave infrared radiation, as well as the use of a hard vacuum to essentially eliminate convective and conductive heat losses. This paper describes a new method that determines receiver overall optical efficiency by exposing a fluid-filled, pre-cooled receiver to one sun outdoors and measuring the slopemore » of the temperature curve at the point where the receiver temperature passes the glass envelope temperature (that is, the point at which there is no heat gain or loss from the absorber). This transient test method offers the potential advantages of simplicity, high accuracy, and the use of the actual solar spectrum.« less

Construction and simulation of a novel continuous traffic flow model

NASA Astrophysics Data System (ADS)

Hwang, Yao-Hsin; Yu, Jui-Ling

2017-12-01

In this paper, we aim to propose a novel mathematical model for traffic flow and apply a newly developed characteristic particle method to solve the associate governing equations. As compared with the existing non-equilibrium higher-order traffic flow models, the present one is put forward to satisfy the following three conditions: Preserve the equilibrium state in the smooth region. Yield an anisotropic propagation of traffic flow information. Expressed with a conservation law form for traffic momentum. These conditions will ensure a more practical simulation in traffic flow physics: The current traffic will not be influenced by the condition in the behind and result in unambiguous condition across a traffic shock. Through analyses of characteristics, stability condition and steady-state solution adherent to the equation system, it is shown that the proposed model actually conform to these conditions. Furthermore, this model can be cast into its characteristic form which, incorporated with the Rankine-Hugoniot relation, is appropriate to be simulated by the characteristic particle method to obtain accurate computational results.

local alternative sources for cogeneration combined heat and power system

NASA Astrophysics Data System (ADS)

Agll, Abdulhakim Amer

Global demand for energy continues to grow while countries around the globe race to reduce their reliance on fossil fuels and greenhouse gas emissions by implementing policy measures and advancing technology. Sustainability has become an important issue in transportation and infrastructure development projects. While several agencies are trying to incorporate a range of sustainability measures in their goals and missions, only a few planning agencies have been able to implement these policies and they are far from perfect. The low rate of success in implementing sustainable policies is primarily due to incomplete understanding of the system and the interaction between various elements of the system. The conventional planning efforts focuses mainly on performance measures pertaining to the system and its impact on the environment but seldom on the social and economic impacts. The objective of this study is to use clean and alternative energy can be produced from many sources, and even use existing materials for energy generation. One such pathway is using wastewater, animal and organic waste, or landfills to create biogas for energy production. There are three tasks for this study. In topic one evaluated the energy saving that produced from combined hydrogen, heat, and power and mitigate greenhouse gas emissions by using local sustainable energy at the Missouri S&T campus to reduce energy consumption and fossil fuel usage. Second topic aimed to estimate energy recovery and power generation from alternative energy source by using Rankin steam cycle from municipal solid waste at Benghazi-Libya. And the last task is in progress. The results for topics one and two have been presented.

A 10-KILOWATT, RANKINE CYCLE, WASTE-TO-ENERGY CONVERSION MODULE UTILIZING ULTRA MICRO TURBO-ALTERNATORS - PHASE II

EPA Science Inventory

In 2011, there were 60,000 dairy farms in the United States. Of these, 56,600 had herds of fewer than 500 animals. Currently, manure digester installations are only considered economical for herds of at least 500 animals. These require turbine or diesel generator sets of 10...

Engaging & Challenging Gifted Students: Tips for Supporting Extraordinary Minds in Your Classroom (ASCD Arias)

ERIC Educational Resources Information Center

Rankin, Jenny Grant

2016-01-01

Though nearly 5 million students can be characterized as gifted and talented in the United States, many exceptional learners "fly under the radar." Because they are not appropriately challenged in the general classroom, they never meet their full potential--in school or in life. Author Jenny Grant Rankin equips general classroom teachers…

Transcript for: Why Data Should Be Over-the-Counter. TEDxTUM

ERIC Educational Resources Information Center

Rankin, Jenny Grant

2015-01-01

Data is critical, but data has not always lead to success. If data is not communicated clearly, the results can be disastrous. Design lets us communicate data so it can be understood. Dr. Rankin believes that "when we're fluent in visualizing our ideas, we can communicate them across global boundaries, across spoken language barriers, and…

College and Adult Reading I; First Annual Yearbook.

ERIC Educational Resources Information Center

Raygor, Alton L., Ed.

This yearbook is a report of the papers presented at the Fourth Annual Meeting of the North Central Reading Association. The titles and authors of the papers included are: "Recent Research in College and Adult Reading" by Edward G. Summers; "The Definition of Reading" by Earl F. Rankin; "The Effect of Reading Training on College Achievement" by…

Concentrating Solar Power Projects - Yumen 50MW Molten Salt Tower CSP

Science.gov Websites

: Yumen (Gansu Province) Owner(s): Yumen Xinneng Thermal Power Co., Ltd Technology: Power tower Turbine Developer(s): China Sinogy Electric Engineering Co., Ltd Owner(s) (%): Yumen Xinneng Thermal Power Co., Ltd (Gross): 50.0 MW Turbine Capacity (Net): 50.0 MW Output Type: Steam Rankine Thermal Storage Storage Type

Numerical characterization under uncertainties of a piston expander for exhaust heat recovery on heavy commercial vehicles

NASA Astrophysics Data System (ADS)

Congedo, P. M.; Melis, J.; Daccord, R.

2017-03-01

While nearly 30 percent of the fuel energy is lost as waste heat in the form of hot exhaust gases, exhaust heat recovery promises one of the biggest fuel economy potential regarding the technologies available in the next decade. Applied to heavy commercial vehicles (HCVs), buses or off road vehicles, a bottoming Rankine Cycle (RC) on exhaust heat shows a great potential in recovering the exhaust gases energy, even for part loads. The objective of this paper is to illustrates the interest in assessing the uncertainty of this kind of systems for getting a robust prediction of the associated numerical model. In particular, the focus here is on the simulation of a piston expander for exhaust heat recovery. Uncertainties associated to the experimental measurements are propagated through the numerical code by means of uncertainty quantification techniques. Several sources of uncertainties are taken into account at the same time, thus yielding various indications concerning the most predominant parameters, and their influence on several quantities of interest, such as the mechanical power, the mass flow and the exhaust temperature.

Office Immunotherapy in Chronic Inflammatoryh Demyelinating Polyneuropathy and Multifocal Motor Neuropathy

PubMed Central

Dyck, Peter J.; Taylor, Bruce V.; Davies, Jenny L.; Mauermann, Michelle L.; Litchy, William J.; Klein, Christopher J.; Dyck, P. James B.

2015-01-01

Background Intravenous immunoglobulin [IVIg], plasma exchange [PE], and corticosteroids are efficacious treatment in chronic inflammatory demyelinating polyneuropathy [CIDP]. IVIg is effective in multifocal motor neuropathy [MMN]. Objective and Methods Results and Conclusions NIS, NIS-weakness, sum scores of raw amplitudes of motor fiber (CMAPs) amplitudes, and Dyck/Rankin score provided reliable measures to detect and scale abnormality and reflect change; they are therefore ideal for office management of response-basedimmunotherapy (R-IRx) of CIDP. Using efficacious R-IRx, a large early and late therapeutic response (≥ one-fourth were in remission or had recovered) was demonstrated in CIDP. In MMN only an early improvement with late non-significant worsening was observed. The difference in immunotherapy response supports a fundamental difference between CIDP (immune attack on Schwann cells and myelin) and MMN (attack on nodes of Ranvier and axons). PMID:25976871

Numerical solutions of several reflected shock-wave flow fields with nonequilibrium chemical reactions

NASA Technical Reports Server (NTRS)

Hanson, R. K.; Presley, L. L.; Williams, E. V.

1972-01-01

The method of characteristics for a chemically reacting gas is used in the construction of the time-dependent, one-dimensional flow field resulting from the normal reflection of an incident shock wave at the end wall of a shock tube. Nonequilibrium chemical reactions are allowed behind both the incident and reflected shock waves. All the solutions are evaluated for oxygen, but the results are generally representative of any inviscid, nonconducting, and nonradiating diatomic gas. The solutions clearly show that: (1) both the incident- and reflected-shock chemical relaxation times are important in governing the time to attain steady state thermodynamic properties; and (2) adjacent to the end wall, an excess-entropy layer develops wherein the steady state values of all the thermodynamic variables except pressure differ significantly from their corresponding Rankine-Hugoniot equilibrium values.

Development of a solar-powered residential air conditioner

NASA Technical Reports Server (NTRS)

1975-01-01

An extensive review of the literature was conducted which was concerned with the characterization of systems and equipment that could be applicable to the development of solar-powered air conditioners based on the Rankine cycle approach, and the establishment of baseline data defining the performance, physical characteristics, and cost of systems using the LiBr/H2O absorption cycle.

Progress in solar thermal distributed receiver technology

NASA Astrophysics Data System (ADS)

Leonard, J. A.; Otts, J. V.

A brief discussion is given on the fundamentals of parabolic dish collectors. Private and Department of Energy supported projects which employ parabolic dish collector systems are described. These projects include: the Distribution Receiver Test Facility, Shenandoah Solar Total Energy Project, Vangurd I, Solar Plant No. 1, the Dish/Stirling Solar Electric Generating System, the Organic Rankine Cycle, and the Solarized Automotive Gas Turbine.

Survey of Current and Next Generation Space Power Technologies

DTIC Science & Technology

2006-06-26

different thermodynamic cycles, such as the Brayton, Rankine, and Stirling cycles, alkali metal thermal electric converters ( AMTEC ) and thermionic...efficiencies @ 1700K. The primary issue with this system is the integration of the converter technology into the nuclear reactor core. AMTEC (static...Alkali metal thermal to electric converters ( AMTECs ) are thermally powered electrochemical concentration cells that convert heat energy directly to DC

Geostrophic Vortex Dynamics

DTIC Science & Technology

1988-10-01

Generalized Kirchhoff Vortices 176 B. The 2-Level Rankine Vortex: Critical Points & Stability 181 C. Tripolar Coherent Euler Vortices 186 7...spontaneously in spectral simulations. One such example is provided by the tripolar vortex structureE which will be examined in detail in Chapter 6. It...of the tripolar coherent vortex structures that have recently been observed in very high resolution numerical simulations of two- dimensional

Coolidge solar powered irrigation pumping project

NASA Technical Reports Server (NTRS)

Larson, D. L.

1980-01-01

A 150 kW solar thermal electric power plant which includes over 2100 square meters of parabolic trough type collectors and an organic Rankine cycle turbine engine was constructed on an irrigated farm. The plant is interconnected with the electrical utility grid. Operation is providing an evaluation of equipment performance and operating and maintenance requirements as well as the desirability of an on farm location.

Early developments in solar cooling equipment

NASA Technical Reports Server (NTRS)

Price, J. M.

1978-01-01

A brief description of a development program to design, fabricate and field test a series of solar operated or driven cooling devices, undertaken by the Marshall Space Flight Center in the context of the Solar Heating and Cooling Demonstration Act of 1974, is presented. Attention is given to two basic design concepts: the Rankine cycle principle and the use of a dessicant for cooling.

Solar power satellite, system definition study. Part 2, volume 3: SPS satellite systems

NASA Technical Reports Server (NTRS)

1977-01-01

The differences in approach to solar energy conversion by solar cells and thermal engine systems are examined. Systems requirements for the solar power satellite (SPS) are given along with a description of the primary subsystems. Trades leading to exact configuration selection, for example, selection of the Rankine cycle operating temperatures are explained, and two satellite configurations are discussed.

Concentrating Solar Power Projects - Ilanga I | Concentrating Solar Power |

Science.gov Websites

Fluid Type: Thermal oil Solar-Field Inlet Temp: 293°C Solar-Field Outlet Temp: 393°C Power Block Turbine Capacity (Gross): 100.0 MW Turbine Capacity (Net): 100.0 MW Output Type: Steam Rankine Thermal Storage Storage Type: 2-tank indirect Storage Capacity: 4.5 hours Thermal Storage Description: Molten salt

Megawatt Class Nuclear Space Power Systems (MCNSPS) conceptual design and evaluation report. Volume 4: Concepts selection, conceptual designs, recommendations

NASA Technical Reports Server (NTRS)

Wetch, J. R.

1988-01-01

A study was conducted by NASA Lewis Research Center for the Triagency SP-100 program office. The objective was to determine which reactor, conversion and radiator technologies would best fulfill future Megawatt Class Nuclear Space Power System Requirements. The requirement was 10 megawatts for 5 years of full power operation and 10 years system life on orbit. A variety of liquid metal and gas cooled reactors, static and dynamic conversion systems, and passive and dynamic radiators were considered. Four concepts were selected for more detailed study: (1) a gas cooled reactor with closed cycle Brayton turbine-alternator conversion with heatpipe and pumped tube fin rejection, (2) a Lithium cooled reactor with a free piston Stirling engine-linear alternator and a pumped tube-fin radiator,(3) a Lithium cooled reactor with a Potassium Rankine turbine-alternator and heat pipe radiator, and (4) a Lithium cooled incore thermionic static conversion reactor with a heat pipe radiator. The systems recommended for further development to meet a 10 megawatt long life requirement are the Lithium cooled reactor with the K-Rankine conversion and heat pipe radiator, and the Lithium cooled incore thermionic reactor with heat pipe radiator.

Low-order models of a single-screw expander for organic Rankine cycle applications

NASA Astrophysics Data System (ADS)

Ziviani, D.; Desideri, A.; Lemort, V.; De Paepe, M.; van den Broek, M.

2015-08-01

Screw-type volumetric expanders have been demonstrated to be a suitable technology for organic Rankine cycle (ORC) systems because of higher overall effectiveness and good part-load behaviour over other positive displacement machines. An 11 kWe single-screw expander (SSE) adapted from an air compressor has been tested in an ORC test-rig operating with R245fa as working fluid. A total of 60 steady-steady points have been obtained at four different rotational speeds of the expander in the range between 2000 rpm and 3300 rpm. The maximum electrical power output and overall isentropic effectiveness measured were 7.3 kW and 51.9%, respectively. In this paper, a comparison between two low-order models is proposed in terms of accuracy of the predictions, the robustness of the model and the computational time. The first model is the Pacejka equation-based model and the second is a semi-empirical model derived from a well-known scroll expander model and modified to include the geometric aspects of a single screw expander. The models have been calibrated with the available steady-state measurement points by identifying the proper parameters.

Waste heat recovery from adiabatic diesel engines by exhaust-driven Brayton cycles

NASA Technical Reports Server (NTRS)

Khalifa, H. E.

1983-01-01

An evaluation of Bryton Bottoming Systems (BBS) as waste heat recovery devices for future adiabatic diesel engines in heavy duty trucks is presented. Parametric studies were performed to evaluate the influence of external and internal design parameters on BBS performance. Conceptual design and trade-off studies were undertaken to estimate the optimum configuration, size, and cost of major hardware components. The potential annual fuel savings of long-haul trucks equipped with BBS were estimated. The addition of a BBS to a turbocharged, nonaftercooled adiabatic engine would improve fuel economy by as much as 12%. In comparison with an aftercooled, turbocompound engine, the BBS-equipped turbocharged engine would offer a 4.4% fuel economy advantage. If installed in tandem with an aftercooled turbocompound engine, the BBS could effect a 7.2% fuel economy improvement. The cost of a mass-produced 38 Bhp BBS is estimated at about $6460 or 170/Bhp. Technical and economic barriers that hinder the commercial introduction of bottoming systems were identified. Related studies in the area of waste heat recovery from adiabatic diesel engines and NASA-CR-168255 (Steam Rankine) and CR-168256 (Organic Rankine).

Assessment of the potential of solar thermal small power systems in small utilities

NASA Technical Reports Server (NTRS)

Steitz, P.; Mayo, L. G.; Perkins, S. P., Jr.

1978-01-01

The potential economic benefit of small solar thermal electric power systems to small municipal and rural electric utilities is assessed. Five different solar thermal small power system configurations were considered in three different solar thermal technologies. The configurations included: (1) 1 MW, 2 MW, and 10 MW parabolic dish concentrators with a 15 kW heat engine mounted at the focal point of each dish, these systems utilized advanced battery energy storage; (2) a 10 MW system with variable slat concentrators and central steam Rankine energy conversion, this system utilized sensible thermal energy storage; and (3) a 50 MW central receiver system consisting of a field of heliostats concentrating energy on a tower-mounted receiver and a central steam Rankine conversion system, this system also utilized sensible thermal storage. The results are summarized in terms of break-even capital costs. The break-even capital cost was defined as the solar thermal plant capital cost which would have to be achieved in order for the solar thermal plants to penetrate 10 percent of the reference small utility generation mix by the year 2000. The calculated break-even capital costs are presented.

Milestone Report #2: Direct Evaporator Leak and Flammability Analysis Modifications and Optimization of the Organic Rankine Cycle to Improve the Recovery of Waste Heat

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

Guillen, Donna Post

2013-09-01

The direct evaporator is a simplified heat exchange system for an Organic Rankine Cycle (ORC) that generates electricity from a gas turbine exhaust stream. Typically, the heat of the exhaust stream is transferred indirectly to the ORC by means of an intermediate thermal oil loop. In this project, the goal is to design a direct evaporator where the working fluid is evaporated in the exhaust gas heat exchanger. By eliminating one of the heat exchangers and the intermediate oil loop, the overall ORC system cost can be reduced by approximately 15%. However, placing a heat exchanger operating with a flammablemore » hydrocarbon working fluid directly in the hot exhaust gas stream presents potential safety risks. The purpose of the analyses presented in this report is to assess the flammability of the selected working fluid in the hot exhaust gas stream stemming from a potential leak in the evaporator. Ignition delay time for cyclopentane at temperatures and pressure corresponding to direct evaporator operation was obtained for several equivalence ratios. Results of a computational fluid dynamic analysis of a pinhole leak scenario are given.« less

The Riemann problem for the relativistic full Euler system with generalized Chaplygin proper energy density-pressure relation

NASA Astrophysics Data System (ADS)

Shao, Zhiqiang

2018-04-01

The relativistic full Euler system with generalized Chaplygin proper energy density-pressure relation is studied. The Riemann problem is solved constructively. The delta shock wave arises in the Riemann solutions, provided that the initial data satisfy some certain conditions, although the system is strictly hyperbolic and the first and third characteristic fields are genuinely nonlinear, while the second one is linearly degenerate. There are five kinds of Riemann solutions, in which four only consist of a shock wave and a centered rarefaction wave or two shock waves or two centered rarefaction waves, and a contact discontinuity between the constant states (precisely speaking, the solutions consist in general of three waves), and the other involves delta shocks on which both the rest mass density and the proper energy density simultaneously contain the Dirac delta function. It is quite different from the previous ones on which only one state variable contains the Dirac delta function. The formation mechanism, generalized Rankine-Hugoniot relation and entropy condition are clarified for this type of delta shock wave. Under the generalized Rankine-Hugoniot relation and entropy condition, we establish the existence and uniqueness of solutions involving delta shocks for the Riemann problem.

Automated brain computed tomographic densitometry of early ischemic changes in acute stroke

PubMed Central

Stoel, Berend C.; Marquering, Henk A.; Staring, Marius; Beenen, Ludo F.; Slump, Cornelis H.; Roos, Yvo B.; Majoie, Charles B.

2015-01-01

Abstract. The Alberta Stroke Program Early CT score (ASPECTS) scoring method is frequently used for quantifying early ischemic changes (EICs) in patients with acute ischemic stroke in clinical studies. Varying interobserver agreement has been reported, however, with limited agreement. Therefore, our goal was to develop and evaluate an automated brain densitometric method. It divides CT scans of the brain into ASPECTS regions using atlas-based segmentation. EICs are quantified by comparing the brain density between contralateral sides. This method was optimized and validated using CT data from 10 and 63 patients, respectively. The automated method was validated against manual ASPECTS, stroke severity at baseline and clinical outcome after 7 to 10 days (NIH Stroke Scale, NIHSS) and 3 months (modified Rankin Scale). Manual and automated ASPECTS showed similar and statistically significant correlations with baseline NIHSS (R=−0.399 and −0.277, respectively) and with follow-up mRS (R=−0.256 and −0.272), except for the follow-up NIHSS. Agreement between automated and consensus ASPECTS reading was similar to the interobserver agreement of manual ASPECTS (differences <1 point in 73% of cases). The automated ASPECTS method could, therefore, be used as a supplementary tool to assist manual scoring. PMID:26158082

Safety of tPA in stroke mimics and neuroimaging-negative cerebral ischemia(Podcast)(e–Pub ahead of print)(CME)

PubMed Central

Chernyshev, O.Y.; Martin-Schild, S.; Albright, K.C.; Barreto, A.; Misra, V.; Acosta, I.; Grotta, J.C.; Savitz, S.I.

2010-01-01

Background: Patients with acute neurologic symptoms may have other causes simulating ischemic stroke, called stroke mimics (SM), but they may also have averted strokes that do not appear as infarcts on neuroimaging, which we call neuroimaging-negative cerebral ischemia (NNCI). We determined the safety and outcome of IV thrombolysis within 3 hours of symptom onset in patients with SM and NNCI. Methods: Patients treated with IV tissue plasminogen activator (tPA) within 3 hours of symptom onset were identified from our stroke registry from June 2004 to October 2008. We collected admission NIH Stroke Scale (NIHSS) score, modified Rankin score (mRS), length of stay (LOS), symptomatic intracerebral hemorrhage (sICH), and discharge diagnosis. Results: Among 512 treated patients, 21% were found not to have an infarct on follow-up imaging. In the SM group (14%), average age was 55 years, median admission NIHSS was 7, median discharge NIHSS was 0, median LOS was 3 days, and there were no instances of sICH. The most common etiologies were seizure, complicated migraine, and conversion disorder. In the NNCI group (7%), average age was 61 years, median admission NIHSS was 7, median discharge NIHSS was 0, median LOS was 3 days, and there were no instances of sICH. Nearly all SM (87%) and NNCI (91%) patients were functionally independent on discharge (mRS 0–1). Conclusions: Our data support the safety of administering IV tissue plasminogen activator to patients with suspected acute cerebral ischemia within 3 hours of symptom onset, even when the diagnosis ultimately is found not to be stroke or imaging does not show an infarct. GLOSSARY AIS = acute ischemic stroke; CI = confidence interval; DWI = diffusion-weighted imaging; ED = emergency department; LOS = length of stay; mRS = modified Rankin score; NIHSS = NIH Stroke Scale; NNCI = neuroimaging-negative cerebral ischemia; OR = odds ratio; sICH = symptomatic intracerebral hemorrhage; SM = stroke mimics; tPA = tissue plasminogen activator. PMID:20335564

POST-NOAC: Portuguese observational study of intracranial hemorrhage on non-vitamin K antagonist oral anticoagulants.

PubMed

Marques-Matos, Cláudia; Alves, José Nuno; Marto, João Pedro; Ribeiro, Joana Afonso; Monteiro, Ana; Araújo, José; Silva, Fernando; Grenho, Fátima; Viana-Baptista, Miguel; Sargento-Freitas, João; Pinho, João; Azevedo, Elsa

2017-08-01

Background There is a lower reported incidence of intracranial hemorrhage with non-vitamin K antagonist oral anticoagulants compared with vitamin K antagonist. However, the functional outcome and mortality of intracranial hemorrhage patients were not assessed. Aims To compare the outcome of vitamin K antagonists- and non-vitamin K antagonist oral anticoagulants-related intracranial hemorrhage. Methods We included consecutive patients with acute non-traumatic intracranial hemorrhage on oral anticoagulation therapy admitted between January 2013 and June 2015 at four university hospitals. Clinical and demographic data were obtained from individual medical records. Intracranial hemorrhage was classified as intracerebral, extra-axial, or multifocal using brain computed tomography. Three-month functional outcome was assessed using the modified Rankin Scale. Results Among 246 patients included, 24 (9.8%) were anticoagulated with a non-vitamin K antagonist oral anticoagulants and 222 (90.2%) with a vitamin K antagonists. Non-vitamin K antagonist oral anticoagulants patients were older (81.5 vs. 76 years, p = 0.048) and had intracerebral hemorrhage more often (83.3% vs. 63.1%, p = 0.048). We detected a non-significant trend for larger intracerebral hemorrhage volumes in vitamin K antagonists patients ( p = 0.368). Survival analysis adjusted for age, CHA 2 DS 2 VASc, HAS-BLED, and anticoagulation reversal revealed that non-vitamin K antagonist oral anticoagulants did not influence three-month mortality (hazard ratio (HR) = 0.83, 95% confidence interval (CI) = 0.39-1.80, p = 0.638). Multivariable ordinal regression for three-month functional outcome did not show a significant shift of modified Rankin Scale scores in non-vitamin K antagonist oral anticoagulants patients (odds ratio (OR) 1.26, 95%CI 0.55-2.87, p = 0.585). Conclusions We detected no significant differences in the three-month outcome between non-vitamin K antagonist oral anticoagulants- and vitamin K antagonists-associated intracranial hemorrhage, despite unavailability of non-vitamin K antagonist oral anticoagulants-specific reversal agents.

Association between executive and food functions in the acute phase after stroke.

PubMed

Mourão, Aline Mansueto; Vicente, Laélia Cristina Caseiro; Abreu, Mery Natali Silva; Chaves, Tatiana Simões; Sant'Anna, Romeu Vale; Braga, Marcela Aline Fernandes; Meira, Fidel Castro Alves de; de Souza, Leonardo Cruz; Miranda, Aline Silva de; Rachid, Milene Alvarenga; Teixeira, Antônio Lucio

2018-03-01

Purpose To investigate potential associations among executive, physical and food functions in the acute phase after stroke. Methods This is a cross-sectional study that evaluated 63 patients admitted to the stroke unit of a public hospital. The exclusion criteria were other neurological and/or psychiatric diagnoses. The tools for evaluation were: Mini-Mental State Examination and Frontal Assessment Battery for cognitive functions; Alberta Stroke Program Early CT Score for quantification of brain injury; National Institutes of Health Stroke Scale for neurological impairment; Modified Rankin Scale for functionality, and the Functional Oral Intake Scale for food function. Results The sample comprised 34 men (54%) and 29 women with a mean age of 63.6 years. The Frontal Assessment Battery was significantly associated with the other scales. In multivariate analysis, executive function was independently associated with the Functional Oral Intake Scale. Conclusion Most patients exhibited executive dysfunction that significantly compromised oral intake.

Propagation of a shock wave in a radiating spherically symmetric distribution of matter

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

Herrera, L.; Nunez, L.

1987-08-01

A method used to study the evolution of radiating spheres reported by Herrera et al. (1980) is extended to the case in which the sphere is divided in two regions by a shock wave front. The equations of state at both sides of the shock are different, and the solutions are matched on it via the Rankine-Hugoniot conditions. The outer-region metric is matched with a Vaidya solution on the boundary surface of the sphere. As an example of the procedure, two known solutions for radiating systems are considered. The matter distribution is free of singularities everywhere within the sphere andmore » a Gaussian-like pulse is assumed to carry out a fraction of the total mass. Exploding models are then obtained. Finally, the results are discussed in the light of recent work on gravitational collapse and supernovae. 29 references.« less

Microfabricated rankine cycle steam turbine for power generation and methods of making the same

NASA Technical Reports Server (NTRS)

Muller, Norbert (Inventor); Lee, Changgu (Inventor); Frechette, Luc (Inventor)

2009-01-01

In accordance with the present invention, an integrated micro steam turbine power plant on-a-chip has been provided. The integrated micro steam turbine power plant on-a-chip of the present invention comprises a miniature electric power generation system fabricated using silicon microfabrication technology and lithographic patterning. The present invention converts heat to electricity by implementing a thermodynamic power cycle on a chip. The steam turbine power plant on-a-chip generally comprises a turbine, a pump, an electric generator, an evaporator, and a condenser. The turbine is formed by a rotatable, disk-shaped rotor having a plurality of rotor blades disposed thereon and a plurality of stator blades. The plurality of stator blades are interdigitated with the plurality of rotor blades to form the turbine. The generator is driven by the turbine and converts mechanical energy into electrical energy.

Proceedings: Fourth Parabolic Dish Solar Thermal Power Program Review

NASA Technical Reports Server (NTRS)

1983-01-01

The results of activities within the parabolic dish technology and applications development program are presented. Stirling, organic Rankine and Brayton module technologies, associated hardware and test results to date; concentrator development and progress; economic analyses; and international dish development activities are covered. Two panel discussions, concerning industry issues affecting solar thermal dish development and dish technology from a utility/user perspective, are also included.

Gas-heat-pump development

NASA Astrophysics Data System (ADS)

Creswick, F. A.

Incentives for the development of gas heat pumps are discussed. Technical progress made on several promising technologies was reviewed. The status of development of gas-engine-driven heat pumps, the absorption cycle for the near- and long-term gas heat pump systems, the Stirling engine, the small Rankine-cycle engines, and gas-turbine-driven heat pump systems were briefly reviewed. Progress in the US, Japan, and Europe is noted.

76 FR 77996 - FFP Project 9 LLC; Notice of Preliminary Permit Application Accepted for Filing and Soliciting...

Federal Register 2010, 2011, 2012, 2013, 2014

2011-12-15

... Water Supply District, located on the Pearl River, in Rankin and Hinds Counties, Mississippi. The sole...' express permission. The proposed project would consist of: (1) A 23,400-foot-long, 64- foot-high earthen dam; (2) a reservoir with a surface area of 32,000 acres and a storage capacity of 341,000 acre-feet...

Thermoelectric Materials - New Directions and Approaches, Symposium Held in San Francisco, California, U.S.A. on March 31-April 3 1997

DTIC Science & Technology

1997-01-01

cycles such as Stirling vs. Brayton vs. Rankine etc., rather than ’merely’ considering alternative ’gases’. Focusing on the process is a radically...Measurments John R. Taylor , University Science Books, Mil Valley CA (1982) 12.) Terry M. Tritt, Science, 272, 1276 (1996) 13.) All the "Q-terms

Effects of Prehospital Thrombolysis in Stroke Patients With Prestroke Dependency.

PubMed

Nolte, Christian H; Ebinger, Martin; Scheitz, Jan F; Kunz, Alexander; Erdur, Hebun; Geisler, Frederik; Braemswig, Tim-Bastian; Rozanski, Michal; Weber, Joachim E; Wendt, Matthias; Zieschang, Katja; Fiebach, Jochen B; Villringer, Kersten; Grittner, Ulrike; Kaczmarek, Sabina; Endres, Matthias; Audebert, Heinrich J

2018-03-01

Data on effects of intravenous thrombolysis on outcome of patients with ischemic stroke who are dependent on assistance in activities of daily living prestroke are scarce. Recent registry based analyses in activities of daily -independent patients suggest that earlier start of intravenous thrombolysis in the prehospital setting leads to better outcomes when compared with the treatment start in hospital. We evaluated whether these observations can be corroborated in patients with prestroke dependency. This observational, retrospective analysis included all patients with acute ischemic stroke depending on assistance before stroke who received intravenous thrombolysis either on the Stroke Emergency Mobile (STEMO) or through conventional in-hospital care (CC) in a tertiary stroke center (Charité, Campus Benjamin Franklin, Berlin) during routine care. Prespecified outcomes were modified Rankin Scale scores of 0 to 3 and survival at 3 months, as well as symptomatic intracranial hemorrhage. Outcomes were adjusted in multivariable logistic regression. Between February 2011 and March 2015, 122 of 427 patients (28%) treated on STEMO and 142 of 505 patients (28%) treated via CC needed assistance before stroke. Median onset-to-treatment times were 97 (interquartile range, 69-159; STEMO) and 135 (interquartile range, 98-184; CC; P <0.001) minutes. After 3 months, modified Rankin Scale scores of 0 to 3 was observed in 48 STEMO patients (39%) versus 35 CC patients (25%; P =0.01) and 86 (70%, STEMO) versus 85 (60%, CC) patients were alive ( P =0.07). After adjustment, STEMO care was favorable with respect to modified Rankin Scale scores of 0 to 3 (odds ratio, 1.99; 95% confidence interval, 1.02-3.87; P =0.042) with a nonsignificant result for survival (odds ratio, 1.73; 95% confidence interval, 0.95-3.16; P =0.07). Symptomatic intracranial hemorrhage occurred in 5 STEMO versus 12 CC patients (4.2% versus 8.5%; P =0.167). The results of this study suggest that earlier, prehospital (as compared with in-hospital) start of intravenous thrombolysis in acute ischemic stroke may translate into better clinical outcome in patients with prestroke dependency. URL: http://www.clinicaltrials.gov. Unique identifier: NCT02358772. © 2018 American Heart Association, Inc.

Advanced power cycles and configurations for solar towers: Modeling and optimization of the decoupled solar combined cycle concept

NASA Astrophysics Data System (ADS)

García-Barberena, Javier; Olcoz, Asier; Sorbet, Fco. Javier

2017-06-01

CSP technologies are essential to allow large shares of renewables into the grid due to their unique ability to cope with the large variability of the energy resource by means of technically and economically feasible thermal energy storage (TES) systems. However, there is still the need and sought to achieve technological breakthroughs towards cost reductions and increased efficiencies. For this, research on advanced power cycles, like the Decoupled Solar Combined Cycle (DSCC) is, are regarded as a key objective. The DSCC concept is, basically, a Combined Brayton-Rankine cycle in which the bottoming cycle is decoupled from the operation of the topping cycle by means of an intermediate storage system. According to this concept, one or several solar towers driving a solar air receiver and a Gas Turbine (Brayton cycle) feed through their exhaust gasses a single storage system and bottoming cycle. This general concept benefits from a large flexibility in its design. On the one hand, different possible schemes related to number and configuration of solar towers, storage systems media and configuration, bottoming cycles, etc. are possible. On the other, within a specific scheme a large number of design parameters can be optimized, including the solar field size, the operating temperatures and pressures of the receiver, the power of the Brayton and Rankine cycles, the storage capacity and others. Heretofore, DSCC plants have been analyzed by means of simple steady-state models with pre-stablished operating parameters in the power cycles. In this work, a detailed transient simulation model for DSCC plants has been developed and is used to analyze different DSCC plant schemes. For each of the analyzed plant schemes, a sensitivity analysis and selection of the main design parameters is carried out. Results show that an increase in annual solar to electric efficiency of 30% (from 12.91 to 16.78) can be achieved by using two bottoming Rankine cycles at two different temperatures, enabling low temperature heat recovery from the receiver and Gas Turbine exhaust gasses.

Mobile Phone-Based Questionnaire for Assessing 3 Months Modified Rankin Score After Acute Stroke: A Pilot Study.

PubMed

Cooray, Charith; Matusevicius, Marius; Wahlgren, Nils; Ahmed, Niaz

2015-10-01

In many countries, a majority of stroke patients are not assessed for long-term functional outcome owing to limited resources and time. We investigated whether automatic assessment of the modified Rankin Scale (mRS) based on a mobile phone questionnaire may serve as an alternative to mRS assessments at clinical visits after stroke. We enrolled 62 acute stroke patients admitted to our stroke unit during March to May 2014. Forty-eight patients completed the study. During the stay, patients and/or caregivers were equipped with a mobile phone application in their personal mobile phones. The mobile phone application contained a set of 20 questions, based on the Rankin Focused Assessment, which we previously tested in a pilot study. Three months after inclusion, the mobile phone application automatically prompted the study participants to answer the mRS questionnaire in the mobile phones. Each question or a group of questions in the questionnaire corresponded to a certain mRS score. Using a predefined protocol, the highest mRS score question where the study participant had answered yes was deemed the final mobile mRS score. A few days later, a study personnel performed a clinical visit mRS assessment. The 2 assessments were compared using quadratic weighing κ-statistics. Mean age was 67 years (38% females), and median baseline National Institutes of Health Stroke Scale (NIHSS) score was 5 (interquartile range 2-10.5, range 0-23). Median and mean clinical visit mRS at 3 months was 2 and 2.3, respectively. We found a 62.5% agreement between clinical visit and mobile mRS assessment, weighted kappa 0.89 (95% confidence interval 0.82-0.96), and unweighted kappa 0.53 (95% confidence interval 0.36-0.70). Dichotomized mRS outcome separating functionally independent (mRS score 0-2) from dependent (mRS score 3-5) showed 83% agreement and unweighted kappa of 0.66 (95% confidence interval 0.45-0.87). Mobile phone-based automatic assessments of mRS performed well in comparison with clinical visit mRS and could be used as an alternative in stroke follow-up. © 2015 American Heart Association, Inc.

PROMIS GH (Patient-Reported Outcomes Measurement Information System Global Health) Scale in Stroke: A Validation Study.

PubMed

Katzan, Irene L; Lapin, Brittany

2018-01-01

The International Consortium for Health Outcomes Measurement recently included the 10-item PROMIS GH (Patient-Reported Outcomes Measurement Information System Global Health) scale as part of their recommended Standard Set of Stroke Outcome Measures. Before collection of PROMIS GH is broadly implemented, it is necessary to assess its performance in the stroke population. The objective of this study was to evaluate the psychometric properties of PROMIS GH in patients with ischemic stroke and intracerebral hemorrhage. PROMIS GH and 6 PROMIS domain scales measuring same/similar constructs were electronically collected on 1102 patients with ischemic and hemorrhagic strokes at various stages of recovery from their stroke who were seen in a cerebrovascular clinic from October 12, 2015, through June 2, 2017. Confirmatory factor analysis was performed to evaluate the adequacy of 2-factor structure of component scores. Test-retest reliability and convergent validity of PROMIS GH items and component scores were assessed. Discriminant validity and responsiveness were compared between PROMIS GH and PROMIS domain scales measuring the same or related constructs. Analyses were repeated stratified by stroke subtype and modified Rankin Scale score <2 versus ≥2. There was moderate internal reliability (ordinal α, 0.82-0.88) and marginal model fit for the 2-factor solution for component scores (root mean square error of approximation, 0.11). Convergent validity was good with significant correlations between all PROMIS GH items and PROMIS domain scales ( P <0.001 for all). There was excellent discrimination for all PROMIS GH items and component scores across modified Rankin Scale levels. Good responsiveness (effect size, >0.5) was demonstrated for 8 of the 10 PROMIS GH items. Reliability and validity remained consistent across stroke subtype and disability level (modified Rankin Scale, <2 versus ≥2). PROMIS GH exhibits acceptable performance in patients with stroke. Our findings support International Consortium for Health Outcomes Measurement recommendation to use PROMIS GH as part of the standard set of outcome measures in stroke. © 2017 American Heart Association, Inc.

Safety and Efficacy of Solitaire Stent Thrombectomy

PubMed Central

Campbell, Bruce C.V.; Hill, Michael D.; Rubiera, Marta; Menon, Bijoy K.; Demchuk, Andrew; Donnan, Geoffrey A.; Roy, Daniel; Thornton, John; Dorado, Laura; Bonafe, Alain; Levy, Elad I.; Diener, Hans-Christoph; Hernández-Pérez, María; Pereira, Vitor Mendes; Blasco, Jordi; Quesada, Helena; Rempel, Jeremy; Jahan, Reza; Davis, Stephen M.; Stouch, Bruce C.; Mitchell, Peter J.; Jovin, Tudor G.; Saver, Jeffrey L.

2016-01-01

Background and Purpose— Recent positive randomized trials of endovascular therapy for ischemic stroke used predominantly stent retrievers. We pooled data to investigate the efficacy and safety of stent thrombectomy using the Solitaire device in anterior circulation ischemic stroke. Methods— Patient-level data were pooled from trials in which the Solitaire was the only or the predominant device used in a prespecified meta-analysis (SEER Collaboration): Solitaire FR With the Intention for Thrombectomy as Primary Endovascular Treatment (SWIFT PRIME), Endovascular Treatment for Small Core and Anterior Circulation Proximal Occlusion With Emphasis on Minimizing CT to Recanalization Times (ESCAPE), Extending the Time for Thrombolysis in Emergency Neurological Deficits—Intra-Arterial (EXTEND-IA), and Randomized Trial of Revascularization With Solitaire FR Device Versus Best Medical Therapy in the Treatment of Acute Stroke Due to Anterior Circulation Large Vessel Occlusion Presenting Within Eight Hours of Symptom Onset (REVASCAT). The primary outcome was ordinal analysis of modified Rankin Score at 90 days. The primary analysis included all patients in the 4 trials with 2 sensitivity analyses: (1) excluding patients in whom Solitaire was not the first device used and (2) including the 3 Solitaire-only trials (excluding ESCAPE). Secondary outcomes included functional independence (modified Rankin Score 0–2), symptomatic intracerebral hemorrhage, and mortality. Results— The primary analysis included 787 patients: 401 randomized to endovascular thrombectomy and 386 to standard care, and 82.6% received intravenous thrombolysis. The common odds ratio for modified Rankin Score improvement was 2.7 (2.0–3.5) with no heterogeneity in effect by age, sex, baseline stroke severity, extent of computed tomography changes, site of occlusion, or pretreatment with alteplase. The number needed to treat to reduce disability was 2.5 and for an extra patient to achieve independent outcome was 4.25 (3.29–5.99). Successful revascularization occurred in 77% treated with Solitaire device. The rate of symptomatic intracerebral hemorrhage and overall mortality did not differ between treatment groups. Conclusions— Solitaire thrombectomy for large vessel ischemic stroke was safe and highly effective with substantially reduced disability. Benefits were consistent in all prespecified subgroups. PMID:26888532

Safety and Efficacy of Solitaire Stent Thrombectomy: Individual Patient Data Meta-Analysis of Randomized Trials.

PubMed

Campbell, Bruce C V; Hill, Michael D; Rubiera, Marta; Menon, Bijoy K; Demchuk, Andrew; Donnan, Geoffrey A; Roy, Daniel; Thornton, John; Dorado, Laura; Bonafe, Alain; Levy, Elad I; Diener, Hans-Christoph; Hernández-Pérez, María; Pereira, Vitor Mendes; Blasco, Jordi; Quesada, Helena; Rempel, Jeremy; Jahan, Reza; Davis, Stephen M; Stouch, Bruce C; Mitchell, Peter J; Jovin, Tudor G; Saver, Jeffrey L; Goyal, Mayank

2016-03-01

Recent positive randomized trials of endovascular therapy for ischemic stroke used predominantly stent retrievers. We pooled data to investigate the efficacy and safety of stent thrombectomy using the Solitaire device in anterior circulation ischemic stroke. Patient-level data were pooled from trials in which the Solitaire was the only or the predominant device used in a prespecified meta-analysis (SEER Collaboration): Solitaire FR With the Intention for Thrombectomy as Primary Endovascular Treatment (SWIFT PRIME), Endovascular Treatment for Small Core and Anterior Circulation Proximal Occlusion With Emphasis on Minimizing CT to Recanalization Times (ESCAPE), Extending the Time for Thrombolysis in Emergency Neurological Deficits-Intra-Arterial (EXTEND-IA), and Randomized Trial of Revascularization With Solitaire FR Device Versus Best Medical Therapy in the Treatment of Acute Stroke Due to Anterior Circulation Large Vessel Occlusion Presenting Within Eight Hours of Symptom Onset (REVASCAT). The primary outcome was ordinal analysis of modified Rankin Score at 90 days. The primary analysis included all patients in the 4 trials with 2 sensitivity analyses: (1) excluding patients in whom Solitaire was not the first device used and (2) including the 3 Solitaire-only trials (excluding ESCAPE). Secondary outcomes included functional independence (modified Rankin Score 0-2), symptomatic intracerebral hemorrhage, and mortality. The primary analysis included 787 patients: 401 randomized to endovascular thrombectomy and 386 to standard care, and 82.6% received intravenous thrombolysis. The common odds ratio for modified Rankin Score improvement was 2.7 (2.0-3.5) with no heterogeneity in effect by age, sex, baseline stroke severity, extent of computed tomography changes, site of occlusion, or pretreatment with alteplase. The number needed to treat to reduce disability was 2.5 and for an extra patient to achieve independent outcome was 4.25 (3.29-5.99). Successful revascularization occurred in 77% treated with Solitaire device. The rate of symptomatic intracerebral hemorrhage and overall mortality did not differ between treatment groups. Solitaire thrombectomy for large vessel ischemic stroke was safe and highly effective with substantially reduced disability. Benefits were consistent in all prespecified subgroups. © 2016 The Authors.

HF ground scatter from the polar cap: Ionospheric propagation and ground surface effects

NASA Astrophysics Data System (ADS)

Ponomarenko, P. V.; St. Maurice, J.-P.; Hussey, G. C.; Koustov, A. V.

2010-10-01

In addition to being scattered by the ionospheric field-aligned irregularities, HF radar signals can be reflected by the ionosphere toward the Earth and then scattered back to the radar by the rugged ground surface. These ground scatter (GS) echoes are responsible for a substantial part of the returns observed by HF radars making up the Super Dual Auroral Radar Network (SuperDARN). While a GS component is conventionally used in studying ionosphere dynamics (e.g., traveling ionospheric disturbances, ULF waves), its potential in monitoring the state of the scattering surface remains largely unexploited. To fill this gap, we investigated diurnal and seasonal variation of the ground echo occurrence and location from a poleward-looking SuperDARN radar at Rankin Inlet, Canada. Using colocated ionosonde information, we have shown that seasonal and diurnal changes in the high-latitude ionosphere periodically modulate the overall echo occurrence rate and spatial coverage. In addition, characteristics of GS from a particular geographic location are strongly affected by the state of the underlying ground surface. We have shown that (1) ice sheets rarely produce detectable backscatter, (2) mountain ranges are the major source of GS as they can produce echoes at all seasons of the year, and (3) sea surface becomes a significant source of GS once the Arctic sea ice has melted away. Finally, we discuss how the obtained results can expand SuperDARN abilities in monitoring both the ionosphere and ground surface.

A direct Primitive Variable Recovery Scheme for hyperbolic conservative equations: The case of relativistic hydrodynamics.

PubMed

Aguayo-Ortiz, A; Mendoza, S; Olvera, D

2018-01-01

In this article we develop a Primitive Variable Recovery Scheme (PVRS) to solve any system of coupled differential conservative equations. This method obtains directly the primitive variables applying the chain rule to the time term of the conservative equations. With this, a traditional finite volume method for the flux is applied in order avoid violation of both, the entropy and "Rankine-Hugoniot" jump conditions. The time evolution is then computed using a forward finite difference scheme. This numerical technique evades the recovery of the primitive vector by solving an algebraic system of equations as it is often used and so, it generalises standard techniques to solve these kind of coupled systems. The article is presented bearing in mind special relativistic hydrodynamic numerical schemes with an added pedagogical view in the appendix section in order to easily comprehend the PVRS. We present the convergence of the method for standard shock-tube problems of special relativistic hydrodynamics and a graphical visualisation of the errors using the fluctuations of the numerical values with respect to exact analytic solutions. The PVRS circumvents the sometimes arduous computation that arises from standard numerical methods techniques, which obtain the desired primitive vector solution through an algebraic polynomial of the charges.

A direct Primitive Variable Recovery Scheme for hyperbolic conservative equations: The case of relativistic hydrodynamics

PubMed Central

Mendoza, S.; Olvera, D.

2018-01-01

In this article we develop a Primitive Variable Recovery Scheme (PVRS) to solve any system of coupled differential conservative equations. This method obtains directly the primitive variables applying the chain rule to the time term of the conservative equations. With this, a traditional finite volume method for the flux is applied in order avoid violation of both, the entropy and “Rankine-Hugoniot” jump conditions. The time evolution is then computed using a forward finite difference scheme. This numerical technique evades the recovery of the primitive vector by solving an algebraic system of equations as it is often used and so, it generalises standard techniques to solve these kind of coupled systems. The article is presented bearing in mind special relativistic hydrodynamic numerical schemes with an added pedagogical view in the appendix section in order to easily comprehend the PVRS. We present the convergence of the method for standard shock-tube problems of special relativistic hydrodynamics and a graphical visualisation of the errors using the fluctuations of the numerical values with respect to exact analytic solutions. The PVRS circumvents the sometimes arduous computation that arises from standard numerical methods techniques, which obtain the desired primitive vector solution through an algebraic polynomial of the charges. PMID:29659602

Design and Calibration of the ARL Mach 3 High Reynolds Number Facility

DTIC Science & Technology

1975-01-01

degrees Rankine. Test rhombus determinations included lateral and longitudinal Mach number distributions and flow angularity measurements. A...43 3. THE TUNNEL EMPTY MACH NUMBER DISTRIBUTION 45 4. THE CENTERLINE RMS MACH NUMBER 46 5. FLOW ANGULARITY MEASUREMENTS 46 6. BLOCKAGE TESTS... Angularity Wedge Scale Drawing of Flow Angularity Cone Normalized Surface Pressure Difference versus Angle of Attack at xp/xr = - 0.690 for po

Numerical Simulation of Hydrothermal Salt Separation Process and Analysis and Cost Estimating of Shipboard Liquid Waste Disposal

DTIC Science & Technology

2007-06-01

possible means to improve a variety of processes: supercritical water in steam Rankine cycles (fossil-fuel powered plants), supercritical carbon ... dioxide and supercritical water in advanced nuclear power plants, and oxidation in supercritical water for use in destroying toxic military wastes and...destruction technologies are installed in a class of ship. Additionally, the properties of one waste water destruction medium, supercritical

Male Role Norms Inventory--Short Form (MRNI-SF): Development, Confirmatory Factor Analytic Investigation of Structure, and Measurement Invariance across Gender

ERIC Educational Resources Information Center

Levant, Ronald F.; Hall, Rosalie J.; Rankin, Thomas J.

2013-01-01

The current study reports the development from the Male Role Norms Inventory-Revised (MRNI-R; Levant, Rankin, Williams, Hasan, & Smalley, 2010) of the 21-item MRNI-Short Form (MRNI-SF). Confirmatory factor analysis of MRNI-SF responses from a sample of 1,017 undergraduate participants (549 men, 468 women) indicated that the best fitting "bifactor"…

Small reactor power system for space application

NASA Technical Reports Server (NTRS)

Shirbacheh, M.

1987-01-01

A development history and comparative performance capability evaluation is presented for spacecraft nuclear powerplant Small Reactor Power System alternatives. The choice of power conversion technology depends on the reactor's operating temperature; thermionic, thermoelectric, organic Rankine, and Alkali metal thermoelectric conversion are the primary power conversion subsystem technology alternatives. A tabulation is presented for such spacecraft nuclear reactor test histories as those of SNAP-10A, SP-100, and NERVA.

Development of a solar-powered residential air conditioner

NASA Technical Reports Server (NTRS)

1975-01-01

The initial objective of the program was the optimization (in terms of cost and performance) of a Rankine cycle mechanical refrigeration system which utilizes thermal energy from a flat solar collector for air conditioning residential buildings. However, feasibility investigations of the adsorption process revealed that a dessicant-type air conditioner offers many significant advantages. As a result, limited efforts were expended toward the optimization of such a system.

A Multi-Element Ultrasonic Ranging Array

DTIC Science & Technology

1985-01-01

of local tehiperature, in degrees Rankine (degrees Farenheit + 460 degrees). At 70 degrees F: c = 49.018 V ^60 + 70 = 1128 ft/sec At 30 degrees F...the RS-232. When acknowledged, the ranges sre sequentially dumped out the serial interface and placed by the Scheduler in Page Zero indexed storage...served, such as collision avoidance or object tracking, where absolute accuracies are not as important as is relative information

40 CFR 61.03 - Units and abbreviations.

Code of Federal Regulations, 2012 CFR

2012-07-01

... m=meter m2=square meter m3=cubic meter mg=milligram=10−3gram mm=millimeter=10−3meter Mg=megagram... per minute cc=cubic centimeter Ci=curie d=day °F=degree Fahrenheit ft2=square feet ft3=cubic feet gal... square inch gage °R=degree Rankine µl=microliter=10−6liter v/v=volume per volume yd2=square yards yr=year...

40 CFR 61.03 - Units and abbreviations.

Code of Federal Regulations, 2010 CFR

2010-07-01

... m=meter m2=square meter m3=cubic meter mg=milligram=10−3gram mm=millimeter=10−3meter Mg=megagram... per minute cc=cubic centimeter Ci=curie d=day °F=degree Fahrenheit ft2=square feet ft3=cubic feet gal... square inch gage °R=degree Rankine µl=microliter=10−6liter v/v=volume per volume yd2=square yards yr=year...

40 CFR 61.03 - Units and abbreviations.

Code of Federal Regulations, 2013 CFR

2013-07-01

... m=meter m2=square meter m3=cubic meter mg=milligram=10−3gram mm=millimeter=10−3meter Mg=megagram... per minute cc=cubic centimeter Ci=curie d=day °F=degree Fahrenheit ft2=square feet ft3=cubic feet gal... square inch gage °R=degree Rankine µl=microliter=10−6liter v/v=volume per volume yd2=square yards yr=year...

40 CFR 61.03 - Units and abbreviations.

Code of Federal Regulations, 2011 CFR

2011-07-01

... m=meter m2=square meter m3=cubic meter mg=milligram=10−3gram mm=millimeter=10−3meter Mg=megagram... per minute cc=cubic centimeter Ci=curie d=day °F=degree Fahrenheit ft2=square feet ft3=cubic feet gal... square inch gage °R=degree Rankine µl=microliter=10−6liter v/v=volume per volume yd2=square yards yr=year...

40 CFR 61.03 - Units and abbreviations.

Code of Federal Regulations, 2014 CFR

2014-07-01

... m=meter m2=square meter m3=cubic meter mg=milligram=10−3gram mm=millimeter=10−3meter Mg=megagram... per minute cc=cubic centimeter Ci=curie d=day °F=degree Fahrenheit ft2=square feet ft3=cubic feet gal... square inch gage °R=degree Rankine µl=microliter=10−6liter v/v=volume per volume yd2=square yards yr=year...

The two-dimensional instability of an incompressible vortex in a tube with energy-absorbent walls

NASA Astrophysics Data System (ADS)

Broadbent, E. G.; Moore, D. W.

1994-07-01

We have previously shown that a Rankine vortex in a compressible fluid is unstable to a perturbation in cross section, e.g. to a slightly eccentric ellipse. This result is surprising, because compressibility leads to a loss of energy from the perturbed vortex by acoustic radiation. An explanation, valid for small swirl Mach numbers, was provided by Kop'ev and Leont'ev. For small Mach numbers the flow in the neighborhood of the vortex can be treated as incompressible, from which it follows that the kinetic energy is greater for the circular vortex than for any other nearby shape. Thus the loss of energy by acoustic radiation will result in increasing departures from a circular cross section. We assert here that the instability is not inherently acoustic, but that any mechanism which can remove energy will result in instability. To support our contention, we examine the Rankine vortex in a concentric circular tube which has compliant walls. Linear theory first establishes that the instability exists in this case and an approximate theory for a small region of vorticity shows that the distortion increases indefinitely. This is confirmed, without the restriction on size, by a numerical solution of the integro-differential equation based on contour dynamics.

Organic Rankine Cycle for Residual Heat to Power Conversion in Natural Gas Compressor Station. Part II: Plant Simulation and Optimisation Study

NASA Astrophysics Data System (ADS)

Chaczykowski, Maciej

2016-06-01

After having described the models for the organic Rankine cycle (ORC) equipment in the first part of this paper, this second part provides an example that demonstrates the performance of different ORC systems in the energy recovery application in a gas compressor station. The application shows certain specific characteristics, i.e. relatively large scale of the system, high exhaust gas temperature, low ambient temperature operation, and incorporation of an air-cooled condenser, as an effect of the localization in a compressor station plant. Screening of 17 organic fluids, mostly alkanes, was carried out and resulted in a selection of best performing fluids for each cycle configuration, among which benzene, acetone and heptane showed highest energy recovery potential in supercritical cycles, while benzene, toluene and cyclohexane in subcritical cycles. Calculation results indicate that a maximum of 10.4 MW of shaft power can be obtained from the exhaust gases of a 25 MW compressor driver by the use of benzene as a working fluid in the supercritical cycle with heat recuperation. In relation to the particular transmission system analysed in the study, it appears that the regenerative subcritical cycle with toluene as a working fluid presents the best thermodynamic characteristics, however, require some attention insofar as operational conditions are concerned.

The State of Higher Education for STEM LGBTQQ Faculty/Staff

NASA Astrophysics Data System (ADS)

Rankin, Susan

2012-02-01

It has long been understood---an understanding that has been well supported by research-based evidence---that institutional ``climate'' has a profound effect on any academic community's ability to carry out its tripartite mission of teaching, research, and service (Bauer, 1996; Boyer, 1990; Peterson & Spencer, 1990; Rankin, 1998; 2003; 2010; Rankin & Reason, 2008; Tierney & Dilley, 1996). With the acknowledgment that institutions differ in the level of attention and emphasis on issues campus climate, it is safe to say that a campus climate offering equitable learning opportunities for all students, academic freedom for all faculty, and fairness in employment for all staff and administrators is one of the primary responsibilities of institutions of higher education. The research also suggests that a challenging campus climate exists for LGBTQQ students, faculty and staff. Based on the literature, a challenging climate leads to decreased productivity, decreased sense of value to the community, decreased retention, and negatively influences educational outcomes (Settles, et al. 2006; Trower & Chait (2002); Pascrell & Terenzini, 2005; Whitt, Edison, Pascarella, Terenzini, & Nora, 2001). Little is available in the literature on LGBTQQ faculty in the STEM fields. This program will engage participants in a review of the results of the 2010 project with regard to the experiences of LGBTQQ faculty and staff in the STEM fields.

Bearing development program for a 25 kWe solar-powered organic Rankine-cycle engine

NASA Technical Reports Server (NTRS)

Nesmith, B.

1985-01-01

The bearing development program is summarized for a 25-kWe power conversion subsystem (PCS) consisting of an organic Rankine-cycle engine, and permanent magnetic alternator (PMA) and rectifier to be used in a 100-kWe point-focusing distributed receiver solar power plant. The engine and alternator were hermetically sealed and used toluene as the working fluid. The turbine, alternator, and feed pump (TAP) were mounted on a single shaft operating at speeds up to 60,000 rev/min. Net thermal-to-electric efficiencies in the range of 21 to 23% were demonstrated at the maximum working fluid temperature of 400 C (750 F). A chronological summary of the bearing development program is presented. The primary causes of bearing wear problems were traced to a combination of rotordynamic instability and electrodynamic discharge across the bearing surfaces caused by recirculating currents from the PMA. These problems were resolved by implementing an externally supplied, flooded-bearing lubrication system and by electrically insulating all bearings from the TAP housing. This program resulted in the successful development of a stable, high-speed, toluene-lubricated five-pad tilting-pad journal bearing and Rayleigh step thrust bearing system capable of operating at all inclinations between horizontal and vertical.

Pilot study of intravenous glyburide in patients with a large ischemic stroke.

PubMed

Sheth, Kevin N; Kimberly, W Taylor; Elm, Jordan J; Kent, Thomas A; Mandava, Pitchaiah; Yoo, Albert J; Thomalla, Götz; Campbell, Bruce; Donnan, Geoffrey A; Davis, Stephen M; Albers, Gregory W; Jacobson, Sven; Simard, J Marc; Stern, Barney J

2014-01-01

Preclinical and retrospective clinical data indicate that glyburide, a selective inhibitor of sulfonylurea receptor 1-transient receptor potential melastatin 4, is effective in preventing edema and improving outcome after focal ischemia. We assessed the feasibility of recruiting and treating patients with severe stroke while obtaining preliminary information on the safety and tolerability of RP-1127 (glyburide for injection). We studied 10 patients with acute ischemic stroke, with baseline diffusion-weighted imaging lesion volumes of 82 to 210 cm3, whether treated with intravenous recombinant tissue-type plasminogen activator, age 18 to 80 years, and time to RP-1127≤10 hours. Recruitment was completed within 10 months. The mean age was 50.5 years, and baseline diffusion-weighted image lesion volume was 102±23 cm3. There were no serious adverse events related to drug and no symptomatic hypoglycemia. The increase in ipsilateral hemisphere volume was 50±33 cm3. The proportion of 90-day modified Rankin Scale≤4 was 90% (40% modified Rankin Scale, ≤3). RP-1127 at a dose of 3 mg/d was well tolerated and did not require any dose reductions. A clinical trial of RP-1127 is feasible. URL: http://www.clinicaltrials.gov. Unique identifier: NCT01268683.

Surgical decompression for space-occupying cerebral infarction: outcomes at 3 years in the randomized HAMLET trial.

PubMed

Geurts, Marjolein; van der Worp, H Bart; Kappelle, L Jaap; Amelink, G Johan; Algra, Ale; Hofmeijer, Jeannette

2013-09-01

We assessed whether the effects of surgical decompression for space-occupying hemispheric infarction, observed at 1 year, are sustained at 3 years. Patients with space-occupying hemispheric infarction, who were enrolled in the Hemicraniectomy After Middle cerebral artery infarction with Life-threatening Edema Trial within 4 days after stroke onset, were followed up at 3 years. Outcome measures included functional outcome (modified Rankin Scale), death, quality of life, and place of residence. Poor functional outcome was defined as modified Rankin Scale >3. Of 64 included patients, 32 were randomized to decompressive surgery and 32 to best medical treatment. Just as at 1 year, surgery had no effect on the risk of poor functional outcome at 3 years (absolute risk reduction, 1%; 95% confidence interval, -21 to 22), but it reduced case fatality (absolute risk reduction, 37%; 95% confidence interval, 14-60). Sixteen surgically treated patients and 8 controls lived at home (absolute risk reduction, 27%; 95% confidence interval, 4-50). Quality of life improved between 1 and 3 years in patients treated with surgery. In patients with space-occupying hemispheric infarction, the effects of decompressive surgery on case fatality and functional outcome observed at 1 year are sustained at 3 years. http://www.controlled-trials.com. Unique identifier: ISRCTN94237756.

Computational tool for simulation of power and refrigeration cycles

NASA Astrophysics Data System (ADS)

Córdoba Tuta, E.; Reyes Orozco, M.

2016-07-01

Small improvement in thermal efficiency of power cycles brings huge cost savings in the production of electricity, for that reason have a tool for simulation of power cycles allows modeling the optimal changes for a best performance. There is also a big boom in research Organic Rankine Cycle (ORC), which aims to get electricity at low power through cogeneration, in which the working fluid is usually a refrigerant. A tool to design the elements of an ORC cycle and the selection of the working fluid would be helpful, because sources of heat from cogeneration are very different and in each case would be a custom design. In this work the development of a multiplatform software for the simulation of power cycles and refrigeration, which was implemented in the C ++ language and includes a graphical interface which was developed using multiplatform environment Qt and runs on operating systems Windows and Linux. The tool allows the design of custom power cycles, selection the type of fluid (thermodynamic properties are calculated through CoolProp library), calculate the plant efficiency, identify the fractions of flow in each branch and finally generates a report very educational in pdf format via the LaTeX tool.

Development and Analysis of New Integrated Energy Systems for Sustainable Buildings

NASA Astrophysics Data System (ADS)

Khalid, Farrukh

Excessive consumption of fossil fuels in the residential sector and their associated negative environmental impacts bring a significant challenge to engineers within research and industrial communities throughout the world to develop more environmentally benign methods of meeting energy needs of residential sector in particular. This thesis addresses potential solutions for the issue of fossils fuel consumption in residential buildings. Three novel renewable energy based multigeneration systems are proposed for different types of residential buildings, and a comprehensive assessment of energetic and exergetic performances is given on the basis of total occupancy, energy load, and climate conditions. System 1 is a multigeneration system based on two renewable energy sources. It uses biomass and solar resources. The outputs of System 1 are electricity, space heating, cooling, and hot water. The energy and exergy efficiencies of System 1 are 91.0% and 34.9%, respectively. The results of the optimisation analysis show that the net present cost of System 1 is 2,700,496 and that the levelised cost of electricity is 0.117/kWh. System 2 is a multigeneration system, integrating three renewable energy based subsystems; wind turbine, concentrated solar collector, and Organic Rankine Cycle supplied by a ground source heat exchanger. The outputs of the System 2 are electricity, hot water, heating and cooling. The optimisation analysis shows that net present cost is 35,502 and levelised cost of electricity is 0.186/kWh. The energy and exergy efficiencies of System 2 are found to be 34.6% and 16.2%, respectively. System 3 is a multigeneration system, comprising two renewable energy subsystems-- geothermal and solar to supply power, cooling, heating, and hot water. The optimisation analysis shows that the net present cost of System 3 is 598,474, and levelised cost of electricity of 0.111/kWh. The energy and exergy efficiencies of System 3 are 20.2% and 19.2%, respectively, with outputs of electricity, hot water, cooling and space heating. A performance assessment for identical conditions indicates that System 3 offers the best performance, with the minimum net present cost of 26,001 and levelised cost of electricity of 0.136/kWh.

Application of Thermoelectric Devices to Fuel Cell Power Generation: Demonstration and Evaluation

DTIC Science & Technology

2004-09-01

various forms of the ERDC/CERL TR-04-20 63 Rankine thermodynamic cycle (e.g., reheat, regeneration, supercritical). These central power plants can...placement of the TE Device in the condenser receiv- ing the low-quality steam exhaust or into the closed feedwater heaters used to preheat incoming...ability to more efficiently construct, operate, and maintain its installations and ensure environmental quality and safety at a reduced life- cycle -cost

An Improved Model for a Once-through Counter-Cross-Flow Waste Heat Recovery Unit

DTIC Science & Technology

1983-09-01

RAnkine Cycle Energy Recovery (RACER) system. As conceived, the RACER system will be an unfired waste heat recovery system designed to convert waste... heater to arrive at the feedwater inlet. For the given geometry and flow conditions, the model will calcu- late the water inlet temperature consistent...when given feedwater inlet temperature, steam outlet tempera- ture, operating pressure, inlet and outlet gas conditions and gas flow rate. In this

Randomized assessment of rapid endovascular treatment of ischemic stroke.

PubMed

Goyal, Mayank; Demchuk, Andrew M; Menon, Bijoy K; Eesa, Muneer; Rempel, Jeremy L; Thornton, John; Roy, Daniel; Jovin, Tudor G; Willinsky, Robert A; Sapkota, Biggya L; Dowlatshahi, Dar; Frei, Donald F; Kamal, Noreen R; Montanera, Walter J; Poppe, Alexandre Y; Ryckborst, Karla J; Silver, Frank L; Shuaib, Ashfaq; Tampieri, Donatella; Williams, David; Bang, Oh Young; Baxter, Blaise W; Burns, Paul A; Choe, Hana; Heo, Ji-Hoe; Holmstedt, Christine A; Jankowitz, Brian; Kelly, Michael; Linares, Guillermo; Mandzia, Jennifer L; Shankar, Jai; Sohn, Sung-Il; Swartz, Richard H; Barber, Philip A; Coutts, Shelagh B; Smith, Eric E; Morrish, William F; Weill, Alain; Subramaniam, Suresh; Mitha, Alim P; Wong, John H; Lowerison, Mark W; Sajobi, Tolulope T; Hill, Michael D

2015-03-12

Among patients with a proximal vessel occlusion in the anterior circulation, 60 to 80% of patients die within 90 days after stroke onset or do not regain functional independence despite alteplase treatment. We evaluated rapid endovascular treatment in addition to standard care in patients with acute ischemic stroke with a small infarct core, a proximal intracranial arterial occlusion, and moderate-to-good collateral circulation. We randomly assigned participants to receive standard care (control group) or standard care plus endovascular treatment with the use of available thrombectomy devices (intervention group). Patients with a proximal intracranial occlusion in the anterior circulation were included up to 12 hours after symptom onset. Patients with a large infarct core or poor collateral circulation on computed tomography (CT) and CT angiography were excluded. Workflow times were measured against predetermined targets. The primary outcome was the score on the modified Rankin scale (range, 0 [no symptoms] to 6 [death]) at 90 days. A proportional odds model was used to calculate the common odds ratio as a measure of the likelihood that the intervention would lead to lower scores on the modified Rankin scale than would control care (shift analysis). The trial was stopped early because of efficacy. At 22 centers worldwide, 316 participants were enrolled, of whom 238 received intravenous alteplase (120 in the intervention group and 118 in the control group). In the intervention group, the median time from study CT of the head to first reperfusion was 84 minutes. The rate of functional independence (90-day modified Rankin score of 0 to 2) was increased with the intervention (53.0%, vs. 29.3% in the control group; P<0.001). The primary outcome favored the intervention (common odds ratio, 2.6; 95% confidence interval, 1.7 to 3.8; P<0.001), and the intervention was associated with reduced mortality (10.4%, vs. 19.0% in the control group; P=0.04). Symptomatic intracerebral hemorrhage occurred in 3.6% of participants in intervention group and 2.7% of participants in control group (P=0.75). Among patients with acute ischemic stroke with a proximal vessel occlusion, a small infarct core, and moderate-to-good collateral circulation, rapid endovascular treatment improved functional outcomes and reduced mortality. (Funded by Covidien and others; ESCAPE ClinicalTrials.gov number, NCT01778335.).

Validation of a structured interview for telephone assessment of the modified Rankin Scale in Brazilian stroke patients.

PubMed

Baggio, Jussara A O; Santos-Pontelli, Taiza E G; Cougo-Pinto, Pedro T; Camilo, Millene; Silva, Nathalia F; Antunes, Paula; Machado, Laura; Leite, João P; Pontes-Neto, Octavio M

2014-01-01

The modified Rankin Scale (mRS) is a commonly used scale to assess the functional outcome after stroke. Several studies on mRS showed good reliability, feasibility, and interrater agreement of this scale using a face-to-face assessment. However, telephone assessment is a more time-efficient way to obtain an mRS grade than a face-to-face interview. The aim of this study was to validate the telephone assessment of mRS among the Portuguese using a structured interview in a sample of Brazilian stroke patients. We evaluated 50 stroke outpatients twice. The first interview was face-to-face and the second was made by telephone and the time between the two assessments ranged between 7 and 14 days. Four certified raters evaluated the patients using a structured interview based on a questionnaire previously published in the literature. Raters were blinded for the Rankin score given by the other rater. For both assessments, the rater could also interview a caregiver if necessary. The patients' mean age was 62.8 ± 14.7, mean number of years of study 5.2 ± 3.4, 52% were males, 55.2% of patients needed a caregiver's help to answer the questions. The majority of caregivers were female (85%), mean age 49.1 ± 15, and mean number of years of study 8.3 ± 3.4. Perfect agreement between the telephone and face-to-face assessments was obtained for 27 (54%) patients, corresponding to an unweighted Kappa of 0.44 (95% CI 0.27-0.61) and a weighted Kappa of 0.89. The median of telephone assessment mRS was 3.5 (interquartile range = 2-4) and of face-to-face assessment was 4 (interquartile range = 2-5). There was no difference between the two assessments (Wilcoxon test, p = 0.35). Despite the low education level of our sample, the telephone assessment of functional impairment of stroke patients using a translated and culturally adapted Brazilian Portuguese version of the mRS showed good validity and reliability. Therefore, the telephone assessment of mRS can be used in clinical practice and scientific studies in Brazil. © 2014 S. Karger AG, Basel.

Influence of Renal Impairment on Outcome for Thrombolysis-Treated Acute Ischemic Stroke: ENCHANTED (Enhanced Control of Hypertension and Thrombolysis Stroke Study) Post Hoc Analysis.

PubMed

Carr, Susan J; Wang, Xia; Olavarria, Veronica V; Lavados, Pablo M; Rodriguez, Jorge A; Kim, Jong S; Lee, Tsong-Hai; Lindley, Richard I; Pontes-Neto, Octavio M; Ricci, Stefano; Sato, Shoichiro; Sharma, Vijay K; Woodward, Mark; Chalmers, John; Anderson, Craig S; Robinson, Thompson G

2017-09-01

Renal dysfunction (RD) is associated with poor prognosis after stroke. We assessed the effects of RD on outcomes and interaction with low- versus standard-dose alteplase in a post hoc subgroup analysis of the ENCHANTED (Enhanced Control of Hypertension and Thrombolysis Stroke Study). A total of 3220 thrombolysis-eligible patients with acute ischemic stroke (mean age, 66.5 years; 37.8% women) were randomly assigned to low-dose (0.6 mg/kg) or standard-dose (0.9 mg/kg) intravenous alteplase within 4.5 hours of symptom onset. Six hundred and fifty-nine (19.8%) patients had moderate-to-severe RD (estimated glomerular filtration rate, <60 mL/min per 1.73 m 2 ) at baseline. The impact of RD on death or disability (modified Rankin Scale scores, 2-6) at 90 days, and symptomatic intracerebral hemorrhage, was assessed in logistic regression models. Compared with patients with normal renal function (>90 mL/min per 1.73 m 2 ), those with severe RD (<30 mL/min per 1.73 m 2 ) had increased mortality (adjusted odds ratio, 2.07; 95% confidence interval, 0.89-4.82; P =0.04 for trend); every 10 mL/min per 1.73 m 2 lower estimated glomerular filtration rate was associated with an adjusted 9% increased odds of death from thrombolysis-treated acute ischemic stroke. There was no significant association with modified Rankin Scale scores 2 to 6 (adjusted odds ratio, 1.03; 95% confidence interval, 0.62-1.70; P =0.81 for trend), modified Rankin Scale 3 to 6 (adjusted odds ratio, 1.20; 95% confidence interval, 0.72-2.01; P =0.44 for trend), or symptomatic intracerebral hemorrhage, or any heterogeneity in comparative treatment effects between low-dose and standard-dose alteplase by RD grades. RD is associated with increased mortality but not disability or symptomatic intracerebral hemorrhage in thrombolysis-eligible and treated acute ischemic stroke patients. Uncertainty persists as to whether low-dose alteplase confers benefits over standard-dose alteplase in acute ischemic stroke patients with RD. URL: http://www.clinicaltrials.gov. Unique identifier: NCT01422616. © 2017 American Heart Association, Inc.

High Risk of Seizures and Epilepsy after Decompressive Hemicraniectomy for Malignant Middle Cerebral Artery Stroke
.

PubMed

Brondani, Rosane; Garcia de Almeida, Andrea; Abrahim Cherubini, Pedro; Mandelli Mota, Suelen; de Alencastro, Luiz Carlos; Antunes, Apio Cláudio Martins; Bianchin Muxfeldt, Marino

2017-01-01

Decompressive hemicraniectomy (DHC) is a life-saving procedure for treatment of large malignant middle cerebral artery (MCA) strokes. Post-stroke epilepsy is an additional burden for these patients, but its incidence and the risk factors for its development have been poorly investigated. To report the prevalence and risk factors for post-stroke seizures and post-stroke epilepsy after DHC for treatment of large malignant MCA strokes in a cohort of 36 patients. In a retrospective cohort study of 36 patients we report the timing and incidence of post-stroke epilepsy. We analyzed if age, sex, vascular risk factors, side of ischemia, reperfusion therapy, stroke etiology, extension of stroke, hemorrhagic transformation, ECASS scores, National Institutes of Health Stroke Scale (NIHSS) scores, or modified Rankin scores were risk factors for seizure or epilepsy after DHC for treatment of large MCA strokes. The mean patient follow-up time was 1,086 days (SD = 1,172). Out of 36 patients, 9 (25.0%) died before being discharged. After 1 year, a total of 11 patients (30.6%) had died, but 22 (61.1%) of them had a modified Rankin score ≤4. Thirteen patients (36.1%) developed seizures within the first week after stroke. Seizures occurred in 22 (61.1%) of 36 patients (95% CI = 45.17-77.03%). Out of 34 patients who survived the acute period, 19 (55.9%) developed epilepsy after MCA infarcts and DHC (95% CI = 39.21-72.59%). In this study, no significant differences were observed between the patients who developed seizures or epilepsy and those who remained free of seizures or epilepsy regarding age, sex, side of stroke, presence of the clinical risk factors studied, hemorrhagic transformation, time of craniectomy, and Rankin score after 1 year of stroke. The incidence of seizures and epilepsy after malignant MCA infarcts submitted to DHC might be very high. Seizure might occur precociously in patients who are not submitted to anticonvulsant prophylaxis. The large stroke volume and the large cortical ischemic area seem to be the main risk factors for seizure or epilepsy development in this subtype of stroke.
. © 2017 The Author(s)
. Published by S. Karger AG, Basel.

Paracetamol (Acetaminophen) in stroke 2 (PAIS 2): protocol for a randomized, placebo-controlled, double-blind clinical trial to assess the effect of high-dose paracetamol on functional outcome in patients with acute stroke and a body temperature of 36.5 °C or above.

PubMed

de Ridder, Inger R; de Jong, Frank Jan; den Hertog, Heleen M; Lingsma, Hester F; van Gemert, H Maarten A; Schreuder, A H C M L Tobien; Ruitenberg, Annemieke; Maasland, E Lisette; Saxena, Ritu; Oomes, Peter; van Tuijl, Jordie; Koudstaal, Peter J; Kappelle, L Jaap; Algra, Ale; van der Worp, H Bart; Dippel, Diederik W J

2015-04-01

In the first hours after stroke onset, subfebrile temperatures and fever have been associated with poor functional outcome. In the first Paracetamol (Acetaminophen) in Stroke trial, a randomized clinical trial of 1400 patients with acute stroke, patients who were treated with high-dose paracetamol showed more improvement on the modified Rankin Scale at three-months than patients treated with placebo, but this difference was not statistically significant. In the 661 patients with a baseline body temperature of 37.0 °C or above, treatment with paracetamol increased the odds of functional improvement (odds ratio 1.43; 95% confidence interval: 1.02-1.97). This relation was also found in the patients with a body temperature of 36.5 °C or higher (odds ratio 1.31; 95% confidence interval 1.01-1.68). These findings need confirmation. The study aims to assess the effect of high-dose paracetamol in patients with acute stroke and a body temperature of 36.5 °C or above on functional outcome. The Paracetamol (Acetaminophen) In Stroke 2 trial is a multicenter, randomized, double-blind, placebo-controlled clinical trial. We use a power of 85% to detect a significant difference in the scores on the modified Rankin Scale of the paracetamol group compared with the placebo group at a level of significance of 0.05 and assume a treatment effect of 7%. Fifteen-hundred patients with acute ischemic stroke or intracerebral hemorrhage and a body temperature of 36.5 °C or above will be included within 12 h of symptom onset. Patients will be treated with paracetamol in a daily dose of six-grams or matching placebo for three consecutive days. The Paracetamol (Acetaminophen) In Stroke 2 trial has been registered as NTR2365 in The Netherlands Trial Register. The primary outcome will be improvement on the modified Rankin Scale at three-months as analyzed by ordinal logistic regression. If high-dose paracetamol will be proven effective, a simple, safe, and extremely cheap therapy will be available for many patients with acute stroke worldwide. © 2013 The Authors. International Journal of Stroke © 2013 World Stroke Organization.

Endovascular Therapy after Intravenous t-PA versus t-PA Alone for Stroke

PubMed Central

Broderick, Joseph P.; Palesch, Yuko Y.; Demchuk, Andrew M.; Yeatts, Sharon D.; Khatri, Pooja; Hill, Michael D.; Jauch, Edward C.; Jovin, Tudor G.; Yan, Bernard; Silver, Frank L.; von Kummer, Rüdiger; Molina, Carlos A.; Demaerschalk, Bart M.; Budzik, Ronald; Clark, Wayne M.; Zaidat, Osama O.; Malisch, Tim W.; Goyal, Mayank; Schonewille, Wouter J.; Mazighi, Mikael; Engelter, Stefan T.; Anderson, Craig; Spilker, Judith; Carrozzella, Janice; Ryckborst, Karla J.; Janis, L. Scott; Martin, Renée H.; Foster, Lydia D.; Tomsick, Thomas A.

2013-01-01

BACKGROUND Endovascular therapy is increasingly used after the administration of intravenous tissue plasminogen activator (t-PA) for patients with moderate-to-severe acute ischemic stroke, but whether a combined approach is more effective than intravenous t-PA alone is uncertain. METHODS We randomly assigned eligible patients who had received intravenous t-PA within 3 hours after symptom onset to receive additional endovascular therapy or intravenous t-PA alone, in a 2:1 ratio. The primary outcome measure was a modified Rankin scale score of 2 or less (indicating functional independence) at 90 days (scores range from 0 to 6, with higher scores indicating greater disability). RESULTS The study was stopped early because of futility after 656 participants had undergone randomization (434 patients to endovascular therapy and 222 to intravenous t-PA alone). The proportion of participants with a modified Rankin score of 2 or less at 90 days did not differ significantly according to treatment (40.8% with endovascular therapy and 38.7% with intravenous t-PA; absolute adjusted difference, 1.5 percentage points; 95% confidence interval [CI], −6.1 to 9.1, with adjustment for the National Institutes of Health Stroke Scale [NIHSS] score [8–19, indicating moderately severe stroke, or ≥20, indicating severe stroke]), nor were there significant differences for the predefined subgroups of patients with an NIHSS score of 20 or higher (6.8 percentage points; 95% CI, −4.4 to 18.1) and those with a score of 19 or lower (−1.0 percentage point; 95% CI, −10.8 to 8.8). Findings in the endovascular-therapy and intravenous t-PA groups were similar for mortality at 90 days (19.1% and 21.6%, respectively; P = 0.52) and the proportion of patients with symptomatic intracerebral hemorrhage within 30 hours after initiation of t-PA (6.2% and 5.9%, respectively; P = 0.83). CONCLUSIONS The trial showed similar safety outcomes and no significant difference in functional independence with endovascular therapy after intravenous t-PA, as compared with intravenous t-PA alone. (Funded by the National Institutes of Health and others; ClinicalTrials.gov number, NCT00359424.) PMID:23390923

Outcomes validity and reliability of the modified Rankin scale: implications for stroke clinical trials: a literature review and synthesis.

PubMed

Banks, Jamie L; Marotta, Charles A

2007-03-01

The modified Rankin scale (mRS), a clinician-reported measure of global disability, is widely applied for evaluating stroke patient outcomes and as an end point in randomized clinical trials. Extensive evidence on the validity of the mRS exists across a large but fragmented literature. As new treatments for acute ischemic stroke are submitted for agency approval, an appreciation of the mRS's attributes, specifically its relationship to other stroke evaluation scales, would be valuable for decision-makers to properly assess the impact of a new drug on treatment paradigms. The purpose of this report is to assemble and systematically assess the properties of the mRS to provide decision-makers with pertinent evaluative information. A Medline search was conducted to identify reports in the peer-reviewed medical literature (1957-2006) that provide information on the structure, validation, scoring, and psychometric properties of the mRS and its use in clinical trials. The selection of articles was based on defined criteria that included relevance, study design and use of appropriate statistical methods. Of 224 articles identified by the literature search, 50 were selected for detailed assessment. Inter-rater reliability with the mRS is moderate and improves with structured interviews (kappa 0.56 versus 0.78); strong test-re-test reliability (kappa=0.81 to 0.95) has been reported. Numerous studies demonstrate the construct validity of the mRS by its relationships to physiological indicators such as stroke type, lesion size, perfusion and neurological impairment. Convergent validity between the mRS and other disability scales is well documented. Patient comorbidities and socioeconomic factors should be considered in properly applying and interpreting the mRS. Recent analyses suggest that randomized clinical trials of acute stroke treatments may require a smaller sample size if the mRS is used as a primary end point rather than the Barthel Index. Multiple types of evidence attest to the validity and reliability of the mRS. The reported data support the view that the mRS is a valuable instrument for assessing the impact of new stroke treatments.

Evolutionary Optimization of Centrifugal Nozzles for Organic Vapours

NASA Astrophysics Data System (ADS)

Persico, Giacomo

2017-03-01

This paper discusses the shape-optimization of non-conventional centrifugal turbine nozzles for Organic Rankine Cycle applications. The optimal aerodynamic design is supported by the use of a non-intrusive, gradient-free technique specifically developed for shape optimization of turbomachinery profiles. The method is constructed as a combination of a geometrical parametrization technique based on B-Splines, a high-fidelity and experimentally validated Computational Fluid Dynamic solver, and a surrogate-based evolutionary algorithm. The non-ideal gas behaviour featuring the flow of organic fluids in the cascades of interest is introduced via a look-up-table approach, which is rigorously applied throughout the whole optimization process. Two transonic centrifugal nozzles are considered, featuring very different loading and radial extension. The use of a systematic and automatic design method to such a non-conventional configuration highlights the character of centrifugal cascades; the blades require a specific and non-trivial definition of the shape, especially in the rear part, to avoid the onset of shock waves. It is shown that the optimization acts in similar way for the two cascades, identifying an optimal curvature of the blade that both provides a relevant increase of cascade performance and a reduction of downstream gradients.

Flow Field Mapping of Carbon Dioxide Nozzle Expansion into Vacuum

DTIC Science & Technology

1985-07-01

probe bow shock are adequately defined by the Rankine-Hugoniot relations. For flows that meet these requirements, the pitot probe is a simple and...nozzle lip [i.e. radial location 2.0 in. (5 cm)] could be attributable to the interaction of the probe bow shock with the nozzle lip. The similarity in...microbalance, free-molecule heat-transfer probe , free- m !olecule pressure probe , and a rotary pitot probe were used in this evaluation. (Cant)

Design of a Condenser-Boiler for a Binary Mercury-Organic Rankine Cycle Solar Dynamic Space Power System

DTIC Science & Technology

1987-05-15

Velocity and Temp Profiles 64 10 . Specific Heat Spike in Supercritical Fluid 64 11. Toluene Passage Sizing Model 65 12. Finned and Unfinned Tube Bundles 65...4.. 10 inefficiency of thermal -> shaft -> electrical -> thermal power conversions. Fox El] demonstrated that significant savings can be made in...Mercury inlet temperature (turbine) 1033 OK Toluene inlet temperature (turbine) 644 OK Pinch temperature difference 10 OK M ercury turbine efficiency 0.75

Novel Cyclorotor Control System for Operation at Curtate and Prolate Advance Ratios

DTIC Science & Technology

2012-03-06

control mechanisms used until now pitch the blade by attaching control rods from the blade to a rotating eccentric ring. By varying the position of...this eccentric ring the blades are pitched approximately in a sinusoidal manner with variable amplitude and phase; however, this sinusoidal pitching...Florida, June 25-28, 2007. 19Gerhardt, H., "Paddle Wheel Rotorcraft," U.S. Patent 5,265,827, November 30, 1993. 20Bohorquez, F., Rankins, F., Baeder, J

Annual DOE active solar heating and cooling contractors' review meeting. Premeeting proceedings and project summaries

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

None,

1981-09-01

Ninety-three project summaries are presented which discuss the following aspects of active solar heating and cooling: Rankine solar cooling systems; absorption solar cooling systems; desiccant solar cooling systems; solar heat pump systems; solar hot water systems; special projects (such as the National Solar Data Network, hybrid solar thermal/photovoltaic applications, and heat transfer and water migration in soils); administrative/management support; and solar collector, storage, controls, analysis, and materials technology. (LEW)

Boundary-Layer Bypass Transition Over Large-Scale Bodies

DTIC Science & Technology

2016-12-16

shape of the streamwise velocity profile compared to the flat- plate boundary layer. The research showed that the streamwise wavenumber plays a key role...many works on the suppression of the transitional boundary layer. Most of the results in the literature are for the flat- plate boundary layer but the...behaviour of the velocity and pressure changes with the curvature. This work aims to extend the results of the flat- plate boundary layer to a Rankine

Unruptured Brain Arteriovenous Malformations: Primary ONYX Embolization in ARUBA (A Randomized Trial of Unruptured Brain Arteriovenous Malformations)-Eligible Patients.

PubMed

Singfer, Uri; Hemelsoet, Dimitri; Vanlangenhove, Peter; Martens, Frederic; Verbeke, Luc; Van Roost, Dirk; Defreyne, Luc

2017-12-01

In light of evidence from ARUBA (A Randomized Trial of Unruptured Brain Arteriovenous Malformations), neurovascular specialists had to reconsider deliberate treatment of unruptured brain arteriovenous malformations (uBAVMs). Our objective was to determine the outcomes of uBAVM treated with primary embolization using ethylene vinyl alcohol (ONYX). Patients with uBAVM who met the inclusion criteria of ARUBA and were treated with primary Onyx embolization were assigned to this retrospective study. The primary outcome was the modified Rankin Scale score. Secondary outcomes were stroke or death because of uBAVM or intervention and uBAVM obliteration. Sixty-one patients (mean age, 38 years) were included. The median observation period was 60 months. Patients were treated by embolization alone (41.0%), embolization and radiosurgery (57.4%), or embolization and excision (1.6%). Occlusion was achieved in 44 of 57 patients with completed treatment (77.2%). Forty-seven patients (77.1%) had no clinical impairment at the end of observation (modified Rankin Scale score of <2). Twelve patients (19.7%) reached the outcome of stroke or death because of uBAVM or intervention. Treatment-related mortality was 6.6% (4 patients). In uBAVM, Onyx embolization alone or combined with stereotactic radiosurgery achieves a high occlusion rate. Morbidity remains a challenge, even if it seems lower than in the ARUBA trial. © 2017 American Heart Association, Inc.

Brain Connectivity and Functional Recovery in Patients With Ischemic Stroke.

PubMed

Almeida, Sara Regina Meira; Vicentini, Jessica; Bonilha, Leonardo; De Campos, Brunno M; Casseb, Raphael F; Min, Li Li

2017-01-01

Brain mapping studies have demonstrated that functional poststroke brain reorganization is associated with recovery of motor function. Nonetheless, the specific mechanisms associated with functional reorganization leading to motor recovery are still partly unknown. In this study, we performed a cross-sectional evaluation of poststroke subjects with the following goals: (1) To assess intra- and interhemispheric functional brain activation patterns associated with motor function in poststroke patients with variable degrees of recovery; (2) to investigate the involvement of other nonmotor functional networks in relationship with recovery. We studied 59 individuals: 13 patients with function Rankin > 1 and Barthel < 100; 19 patients with preserved function with Rankin 0-1 and Barthel = 100; and 27 healthy controls. All subjects underwent structural and functional magnetic resonance imaging (3T Philips Achieva, Holland) using the same protocol (TR = 2 seconds, TE = 30 ms, FOV = 240 × 240 × 117, slice = 39). Resting state functional connectivity was used by in-house software, based on SPM12. Among patients with and without preserved function, the functional connectivity between the primary motor region (M1) and the contralateral hemisphere was increased compared with controls. Nonetheless, only patients with decreased function exhibited decreased functional connectivity between executive control, sensorimotor and visuospatial networks. Functional recovery after stroke is associated with preserved functional connectivity of motor to nonmotor networks. Copyright © 2016 by the American Society of Neuroimaging.

Novel evaporator architecture with entrance-length crossflow-paths for supercritical Organic Rankine Cycles

DOE PAGES

Sabau, Adrian S.; Nejad, Ali H.; Klett, James W.; ...

2017-11-26

Here in this article, a novel geometry is proposed for evaporators that are used in Supercritical Organic Rankine Cycles. The proposed geometry consists of successive plenums at several length-scale levels, creating a multi-scale heat exchanger (HX). The channels at the lowest length-scale levels were considered to have their length determined by the thermal entrance-length. Numerical simulations based on turbulent flow correlations for supercritical R134a and water were used to evaluate the performance of heat exchangers. Using the data on pumping power and area of heat exchange, the total present cost was evaluated using a cost model for shell-and-tube heat exchangers.more » With respect to the shell-and-tube baseline case, the cost per heat load and total costs of new HXs is lowered by approximately 20–26% and 15–30%, respectively. This reduction in present costs of the new HXs were found to be attributed to higher operational costs for the shell-and-tube HXs, as evidenced by the higher pumping power, as well their capital investment costs. The cost savings in the new HX designs compared to those of the shell-and-tube HXs, at similar heat load performance, indicate that the new HX architectures proposed in this paper are valid alternatives to traditional HX designs.« less

Exergy optimization for a novel combination of organic Rankine cycles, Stirling cycle and direct expander turbines

NASA Astrophysics Data System (ADS)

Moghimi, Mahdi; Khosravian, Mohammadreza

2018-01-01

In this paper, a novel combination of organic Rankine cycles (ORCs), Stirling cycle and direct expander turbines is modeled and optimized using the genetic algorithm. The Exergy efficiency is considered as an objective function in the genetic algorithm. High efficiency is the main advantage of Stirling cycle, however, it needs nearly isothermal compressor and turbine. Therefore, an argon ORC and a R14 ORC are placed before and after the Striling cycle along with two expander turbines at the end of the line. Each component and cycle of the proposed plant in this article is verified by the previous works available in the literature and good agreement is achieved. The obtained results reveal that 27.98%, 20.86% and 12.90% of the total cold exergy are used by argon ORC, Stirling cycle and R14 ORC, respectively. Therefore, utilization of the Stirling cycle is a good idea for the LNG line cold exergy. The maximum exergy destruction occurs in the heat exchanger after the argon ORC (85.786 kJ/s per one kg/s LNG) due to the wasted cold exergy, which can be used for air conditioning systems in the plant. Finally, it would be shown that the maximum efficiency of the proposed plant is 54.25% and the maximum output power is 355.72 kW.

Neglected transport equations: extended Rankine-Hugoniot conditions and J -integrals for fracture

NASA Astrophysics Data System (ADS)

Davey, K.; Darvizeh, R.

2016-09-01

Transport equations in integral form are well established for analysis in continuum fluid dynamics but less so for solid mechanics. Four classical continuum mechanics transport equations exist, which describe the transport of mass, momentum, energy and entropy and thus describe the behaviour of density, velocity, temperature and disorder, respectively. However, one transport equation absent from the list is particularly pertinent to solid mechanics and that is a transport equation for movement, from which displacement is described. This paper introduces the fifth transport equation along with a transport equation for mechanical energy and explores some of the corollaries resulting from the existence of these equations. The general applicability of transport equations to discontinuous physics is discussed with particular focus on fracture mechanics. It is well established that bulk properties can be determined from transport equations by application of a control volume methodology. A control volume can be selected to be moving, stationary, mass tracking, part of, or enclosing the whole system domain. The flexibility of transport equations arises from their ability to tolerate discontinuities. It is insightful thus to explore the benefits derived from the displacement and mechanical energy transport equations, which are shown to be beneficial for capturing the physics of fracture arising from a displacement discontinuity. Extended forms of the Rankine-Hugoniot conditions for fracture are established along with extended forms of J -integrals.

Exergy optimization for a novel combination of organic Rankine cycles, Stirling cycle and direct expander turbines

NASA Astrophysics Data System (ADS)

Moghimi, Mahdi; Khosravian, Mohammadreza

2018-06-01

In this paper, a novel combination of organic Rankine cycles (ORCs), Stirling cycle and direct expander turbines is modeled and optimized using the genetic algorithm. The Exergy efficiency is considered as an objective function in the genetic algorithm. High efficiency is the main advantage of Stirling cycle, however, it needs nearly isothermal compressor and turbine. Therefore, an argon ORC and a R14 ORC are placed before and after the Striling cycle along with two expander turbines at the end of the line. Each component and cycle of the proposed plant in this article is verified by the previous works available in the literature and good agreement is achieved. The obtained results reveal that 27.98%, 20.86% and 12.90% of the total cold exergy are used by argon ORC, Stirling cycle and R14 ORC, respectively. Therefore, utilization of the Stirling cycle is a good idea for the LNG line cold exergy. The maximum exergy destruction occurs in the heat exchanger after the argon ORC (85.786 kJ/s per one kg/s LNG) due to the wasted cold exergy, which can be used for air conditioning systems in the plant. Finally, it would be shown that the maximum efficiency of the proposed plant is 54.25% and the maximum output power is 355.72 kW.

Experimental investigation of domestic micro-CHP based on the gas boiler fitted with ORC module

NASA Astrophysics Data System (ADS)

Wajs, Jan; Mikielewicz, Dariusz; Bajor, Michał; Kneba, Zbigniew

2016-09-01

The results of investigations conducted on the prototype of vapour driven micro-CHP unit integrated with a gas boiler are presented. The system enables cogeneration of heat and electric energy to cover the energy demand of a household. The idea of such system is to produce electricity for own demand or for selling it to the electric grid - in such situation the system user will became the prosumer. A typical commercial gas boiler, additionally equipped with an organic Rankine cycle (ORC) module based on environmentally acceptable working fluid can be regarded as future generation unit. In the paper the prototype of innovative domestic cogenerative ORC system, consisting of a conventional gas boiler and a small size axial vapour microturbines (in-house designed for ORC and the commercially available for Rankine cycle (RC)), evaporator and condenser were scrutinised. In the course of study the fluid working temperatures, rates of heat, electricity generation and efficiency of the whole system were obtained. The tested system could produce electricity in the amount of 1 kWe. Some preliminary tests were started with water as working fluid and the results for that case are also presented. The investigations showed that domestic gas boiler was able to provide the saturated/superheated ethanol vapour (in the ORC system) and steam (in the RC system) as working fluids.

A counter-rotating vortex pair in inviscid fluid

NASA Astrophysics Data System (ADS)

Habibah, Ummu; Fukumoto, Yasuhide

2017-12-01

We study the motion of a counter-rotating vortex pair with the circulations ±Γ move in incompressible fluid. The assumption is made that the core is very thin, that is the core radius σ is much smaller than the vortex radius d such that ɛ = σ/d ≪ 1. With this condition, the method of matched asymptotic expansion is employed. The solutions of the Navier-Stokes equations and the Biot-Savart law, regarding the inner and outer solutions respectively, are constructed in the form of a small parameter. An asymptotic expansion of the Biot-Savart law near the vortex core provides with the matching condition for an asymptotic expansion for limiting the Navier-Stokes equations for large radius r. The general formula of an anti-parallel vortex pair is established. At leading order O(ɛ0), we apply the special case in inviscid fluid, the Rankine vortex, a circular vortex of uniform vorticity. Furthermore at leading order O(ɛ5) we show the traveling speed of a vortex pair.

The geometry of structural equilibrium

PubMed Central

2017-01-01

Building on a long tradition from Maxwell, Rankine, Klein and others, this paper puts forward a geometrical description of structural equilibrium which contains a procedure for the graphic analysis of stress resultants within general three-dimensional frames. The method is a natural generalization of Rankine’s reciprocal diagrams for three-dimensional trusses. The vertices and edges of dual abstract 4-polytopes are embedded within dual four-dimensional vector spaces, wherein the oriented area of generalized polygons give all six components (axial and shear forces with torsion and bending moments) of the stress resultants. The relevant quantities may be readily calculated using four-dimensional Clifford algebra. As well as giving access to frame analysis and design, the description resolves a number of long-standing problems with the incompleteness of Rankine’s description of three-dimensional trusses. Examples are given of how the procedure may be applied to structures of engineering interest, including an outline of a two-stage procedure for addressing the equilibrium of loaded gridshell rooves. PMID:28405361

Higher-order jump conditions for conservation laws

NASA Astrophysics Data System (ADS)

Oksuzoglu, Hakan

2018-04-01

The hyperbolic conservation laws admit discontinuous solutions where the solution variables can have finite jumps in space and time. The jump conditions for conservation laws are expressed in terms of the speed of the discontinuity and the state variables on both sides. An example from the Gas Dynamics is the Rankine-Hugoniot conditions for the shock speed. Here, we provide an expression for the acceleration of the discontinuity in terms of the state variables and their spatial derivatives on both sides. We derive a jump condition for the shock acceleration. Using this general expression, we show how to obtain explicit shock acceleration formulas for nonlinear hyperbolic conservation laws. We start with the Burgers' equation and check the derived formula with an analytical solution. We next derive formulas for the Shallow Water Equations and the Euler Equations of Gas Dynamics. We will verify our formulas for the Euler Equations using an exact solution for the spherically symmetric blast wave problem. In addition, we discuss the potential use of these formulas for the implementation of shock fitting methods.

Development of a solar-powered residential air conditioner: Screening analysis

NASA Technical Reports Server (NTRS)

1975-01-01

Screening analysis aimed at the definition of an optimum configuration of a Rankine cycle solar-powered air conditioner designed for residential application were conducted. Initial studies revealed that system performance and cost were extremely sensitive to condensing temperature and to the type of condenser used in the system. Consequently, the screening analyses were concerned with the generation of parametric design data for different condenser approaches; i. e., (1) an ambient air condenser, (2) a humidified ambient air condenser (3) an evaporative condenser, and (4) a water condenser (with a cooling tower). All systems feature a high performance turbocompressor and a single refrigerant (R-11) for the power and refrigeration loops. Data were obtained by computerized methods developed to permit system characterization over a broad range of operating and design conditions. The criteria used for comparison of the candidate system approaches were (1) overall system COP (refrigeration effect/solar heat input), (2) auxiliary electric power for fans and pumps, and (3) system installed cost or cost to the user.

A linearized Euler analysis of unsteady flows in turbomachinery

NASA Technical Reports Server (NTRS)

Hall, Kenneth C.; Crawley, Edward F.

1987-01-01

A method for calculating unsteady flows in cascades is presented. The model, which is based on the linearized unsteady Euler equations, accounts for blade loading shock motion, wake motion, and blade geometry. The mean flow through the cascade is determined by solving the full nonlinear Euler equations. Assuming the unsteadiness in the flow is small, then the Euler equations are linearized about the mean flow to obtain a set of linear variable coefficient equations which describe the small amplitude, harmonic motion of the flow. These equations are discretized on a computational grid via a finite volume operator and solved directly subject to an appropriate set of linearized boundary conditions. The steady flow, which is calculated prior to the unsteady flow, is found via a Newton iteration procedure. An important feature of the analysis is the use of shock fitting to model steady and unsteady shocks. Use of the Euler equations with the unsteady Rankine-Hugoniot shock jump conditions correctly models the generation of steady and unsteady entropy and vorticity at shocks. In particular, the low frequency shock displacement is correctly predicted. Results of this method are presented for a variety of test cases. Predicted unsteady transonic flows in channels are compared to full nonlinear Euler solutions obtained using time-accurate, time-marching methods. The agreement between the two methods is excellent for small to moderate levels of flow unsteadiness. The method is also used to predict unsteady flows in cascades due to blade motion (flutter problem) and incoming disturbances (gust response problem).

Passive fire protection--a vital safety role.

PubMed

MacInnes, Callum; Rankin, Richard

2012-06-01

Callum Maclnnes BSc (Hons), AIFireE, an engineer at WSP UK--part of a global design engineering and management consultancy group specialising in property, transport and infrastructure, industry and environment projects--and his colleague, senior engineer, Richard Rankin CEng MEng (Hons) MIFireE, discuss the importance of passive fire protection in healthcare premises at a time when, due particularly to the difficult financial climate, many hospitals are undergoing upgrading and refurbishment, potentially affording an ideal opportunity to ensure that proper fire compartmentation measures are in place.

20131201-1231_Green Machine Florida Canyon Hourly Data

DOE Data Explorer

Thibedeau, Joe

2014-01-08

Employing innovative product developments to demonstrate financial and technical viability of producing electricity from low temperature geothermal fluids, coproduced in a mining operation, by employing ElectraTherm's modular and mobile heat-to-power "micro geothermal" power plant with output capacity expected in the 30-70kWe range. The Green Machine is an Organic Rankine Cycle power plant. The Florida Canyon machine is powered by geothermal brine with air cooled condensing. The data provided is an hourly summary from 01 Dec to 31 Dec 2013.

20131101-1130_Green Machine Florida Canyon Hourly Data

DOE Data Explorer

Thibedeau, Joe

2013-12-02

Employing innovative product developments to demonstrate financial and technical viability of producing electricity from low temperature geothermal fluids, coproduced in a mining operation, by employing ElectraTherm's modular and mobile heat-to-power "micro geothermal" power plant with output capacity expected in the 30-70kWe range. The Green Machine is an Organic Rankine Cycle power plant. The Florida Canyon machine is powered by geothermal brine with air cooled condensing. The data provided is an hourly summary from 01 Nov to 30 Nov 2013.

20130416_Green Machine Florida Canyon Hourly Data

DOE Data Explorer

Vanderhoff, Alex

2013-04-24

Employing innovative product developments to demonstrate financial and technical viability of producing electricity from low temperature geothermal fluids, coproduced in a mining operation, by employing ElectraTherm's modular and mobile heat-to-power "micro geothermal" power plant with output capacity expected in the 30-70kWe range. The Green Machine is an Organic Rankine Cycle power plant. The Florida Canyon machine is powered by geothermal brine with air cooled condensing. The data provided is an hourly summary from 4/16/13.

20131001-1031_Green Machine Florida Canyon Hourly Data

DOE Data Explorer

Thibedeau, Joe

2013-11-05

Employing innovative product developments to demonstrate financial and technical viability of producing electricity from low temperature geothermal fluids, coproduced in a mining operation, by employing ElectraTherm's modular and mobile heat-to-power "micro geothermal" power plant with output capacity expected in the 30-70kWe range. The Green Machine is an Organic Rankine Cycle power plant. The Florida Canyon machine is powered by geothermal brine with air cooled condensing. The data provided is an hourly summary from 1 Oct 2013 to 31 Oct 2013.

20140201-0228_Green Machine Florida Canyon Hourly Data

DOE Data Explorer

Thibedeau, Joe

2014-03-03

Employing innovative product developments to demonstrate financial and technical viability of producing electricity from low temperature geothermal fluids, coproduced in a mining operation, by employing ElectraTherm's modular and mobile heat-to-power "micro geothermal" power plant with output capacity expected in the 30-70kWe range. The Green Machine is an Organic Rankine Cycle power plant. The Florida Canyon machine is powered by geothermal brine with air cooled condensing. The data provided is an hourly summary from 01 Feb to 28 Feb 2014.

20130801-0831_Green Machine Florida Canyon Hourly Data

DOE Data Explorer

Vanderhoff, Alex

2013-09-10

Employing innovative product developments to demonstrate financial and technical viability of producing electricity from low temperature geothermal fluids, coproduced in a mining operation, by employing ElectraTherm's modular and mobile heat-to-power "micro geothermal" power plant with output capacity expected in the 30-70kWe range. The Green Machine is an Organic Rankine Cycle power plant. The Florida Canyon machine is powered by geothermal brine with air cooled condensing. The data provided is an hourly summary from 8/1/13 to 8/31/13.

20140101-0131_Green Machine Florida Canyon Hourly Data

DOE Data Explorer

Thibedeau, Joe

2014-02-03

Employing innovative product developments to demonstrate financial and technical viability of producing electricity from low temperature geothermal fluids, coproduced in a mining operation, by employing ElectraTherm's modular and mobile heat-to-power "micro geothermal" power plant with output capacity expected in the 30-70kWe range. The Green Machine is an Organic Rankine Cycle power plant. The Florida Canyon machine is powered by geothermal brine with air cooled condensing. The data provided is an hourly summary from 01 Jan to 31 Jan 2014.

20140430_Green Machine Florida Canyon Hourly Data

DOE Data Explorer

Thibedeau, Joe

2014-05-05

Employing innovative product developments to demonstrate financial and technical viability of producing electricity from low temperature geothermal fluids, coproduced in a mining operation, by employing ElectraTherm's modular and mobile heat-to-power "micro geothermal" power plant with output capacity expected in the 30-70kWe range. The Green Machine is an Organic Rankine Cycle power plant. The Florida Canyon machine is powered by geothermal brine with air cooled condensing. The data provided is an hourly summary from 01 April to 30 April 2014.

20140301-0331_Green Machine Florida Canyon Hourly Data

DOE Data Explorer

Thibedeau, Joe

2014-04-07

Employing innovative product developments to demonstrate financial and technical viability of producing electricity from low temperature geothermal fluids, coproduced in a mining operation, by employing ElectraTherm's modular and mobile heat-to-power "micro geothermal" power plant with output capacity expected in the 30-70kWe range. The Green Machine is an Organic Rankine Cycle power plant. The Florida Canyon machine is powered by geothermal brine with air cooled condensing. The data provided is an hourly summary from 01 Mar to 31 Mar 2014.

20140501-0531_Green Machine Florida Canyon Hourly Data

DOE Data Explorer

Thibedeau, Joe

2014-06-02

Employing innovative product developments to demonstrate financial and technical viability of producing electricity from low temperature geothermal fluids, coproduced in a mining operation, by employing ElectraTherm's modular and mobile heat-to-power "micro geothermal" power plant with output capacity expected in the 30-70kWe range. The Green Machine is an Organic Rankine Cycle power plant. The Florida Canyon machine is powered by geothermal brine with air cooled condensing. The data provided is an hourly summary from 01 May to 31 May 2014.

20140601-0630_Green Machine Florida Canyon Hourly Data

DOE Data Explorer

Thibedeau, Joe

2014-06-30

Employing innovative product developments to demonstrate financial and technical viability of producing electricity from low temperature geothermal fluids, coproduced in a mining operation, by employing ElectraTherm's modular and mobile heat-to-power "micro geothermal" power plant with output capacity expected in the 30-70kWe range. The Green Machine is an Organic Rankine Cycle power plant. The Florida Canyon machine is powered by geothermal brine with air cooled condensing. The data provided is an hourly summary from 01 June to 30 June 2014.

20140701-0731_Green Machine Florida Canyon Hourly Data

DOE Data Explorer

Thibedeau, Joe

2014-07-31

Employing innovative product developments to demonstrate financial and technical viability of producing electricity from low temperature geothermal fluids, coproduced in a mining operation, by employing ElectraTherm's modular and mobile heat-to-power "micro geothermal" power plant with output capacity expected in the 30-70kWe range. The Green Machine is an Organic Rankine Cycle power plant. The Florida Canyon machine is powered by geothermal brine with air cooled condensing. The data provided is an hourly summary from 01 July to 31 July 2014.

20130901-0930_Green Machine Florida Canyon Hourly Data

DOE Data Explorer

Thibedeau, Joe

2013-10-25

Employing innovative product developments to demonstrate financial and technical viability of producing electricity from low temperature geothermal fluids, coproduced in a mining operation, by employing ElectraTherm's modular and mobile heat-to-power "micro geothermal" power plant with output capacity expected in the 30-70kWe range. The Green Machine is an Organic Rankine Cycle power plant. The Florida Canyon machine is powered by geothermal brine with air cooled condensing. The data provided is an hourly summary from 1 September 2013 to 30 September 2013.

Green Machine Florida Canyon Hourly Data 20130731

DOE Data Explorer

Vanderhoff, Alex

2013-08-30

Employing innovative product developments to demonstrate financial and technical viability of producing electricity from low temperature geothermal fluids, coproduced in a mining operation, by employing ElectraTherm's modular and mobile heat-to-power "micro geothermal" power plant with output capacity expected in the 30-70kWe range. The Green Machine is an Organic Rankine Cycle power plant. The Florida Canyon machine is powered by geothermal brine with air cooled condensing. The data provided is an hourly summary from 7/1/13 to 7/31/13.

20130501-20130531_Green Machine Florida Canyon Hourly Data

DOE Data Explorer

Vanderhoff, Alex

2013-06-18

Employing innovative product developments to demonstrate financial and technical viability of producing electricity from low temperature geothermal fluids, coproduced in a mining operation, by employing ElectraTherm's modular and mobile heat-to-power "micro geothermal" power plant with output capacity expected in the 30-70kWe range. The Green Machine is an Organic Rankine Cycle power plant. The Florida Canyon machine is powered by geothermal brine with air cooled condensing. The data provided is an hourly summary from May 2013

Green Machine Florida Canyon Hourly Data

DOE Data Explorer

Vanderhoff, Alex

2013-07-15

Employing innovative product developments to demonstrate financial and technical viability of producing electricity from low temperature geothermal fluids, coproduced in a mining operation, by employing ElectraTherm's modular and mobile heat-to-power "micro geothermal" power plant with output capacity expected in the 30-70kWe range. The Green Machine is an Organic Rankine Cycle power plant. The Florida Canyon machine is powered by geothermal brine with air cooled condensing. The data provided is an hourly summary from 6/1/13 to 6/30/13

Optimization of a point-focusing, distributed receiver solar thermal electric system

NASA Technical Reports Server (NTRS)

Pons, R. L.

1979-01-01

This paper presents an approach to optimization of a solar concept which employs solar-to-electric power conversion at the focus of parabolic dish concentrators. The optimization procedure is presented through a series of trade studies, which include the results of optical/thermal analyses and individual subsystem trades. Alternate closed-cycle and open-cycle Brayton engines and organic Rankine engines are considered to show the influence of the optimization process, and various storage techniques are evaluated, including batteries, flywheels, and hybrid-engine operation.

Design of Conventional Submarines with Advanced Air Independent Propulsion Systems and Determination of Corresponding Theater-Level Impacts

DTIC Science & Technology

2010-01-01

rescue vehicle e: Error term ft: Feet HDW: Howaldtswerke- Deutsche Werft GmbH PEMFC : Proton exchange membrane fuel cells IR: Indiscretion rate/ratio...engines &Rankine cycle power plants &Closed cycle engines A PEMFC AIP system is fitted in the 212 class of submarines that German shipbuilders How...bines a conventional system consisting of a diesel engine and a lead acid battery, with the PEMFC AIP system used for slow, silent cruising. The AIP

Energy Self-Sufficiency for Air Force Logistics Command (AFLC) Bases: An Initial Investigation.

DTIC Science & Technology

1980-06-01

34bottoming cycle ," the system works best for heavy duty trucks on long hauls at constant speeds. Known as the Diesel-Organic Rankine compound engine, it...tolerance for the natural cycle variations of temperature, tides and flows. The range of tolerance is not great for any species and very narrow for some. An...methanol would serve as fuel for a combined- cycle gas tur- bine electrical generator (24:39-40). Coal gasification is presently being considered by the

Control system development for an organic Ranking cycle engine

NASA Technical Reports Server (NTRS)

Bergthold, F. M., Jr.; Fulton, D. G.; Haskins, H. J.

1981-01-01

An organic Rankine cycle engine is used as part of a solar thermal power conversion assembly (PCA). The PCA, including a direct-heated cavity receiver and a shaft-mounted alternator, is mounted at the focal point of a parabolic dish concentrator. The engine controls are required to maintain approximately constant values of turbine inlet temperature and shaft speed, despite variation in the concentrated solar power input to the receiver. The controls design approach, system models, and initial stability and performance analysis results are presented herein.

Thermodynamic power stations at low temperatures

NASA Astrophysics Data System (ADS)

Malherbe, J.; Ployart, R.; Alleau, T.; Bandelier, P.; Lauro, F.

The development of low-temperature thermodynamic power stations using solar energy is considered, with special attention given to the choice of the thermodynamic cycle (Rankine), working fluids (frigorific halogen compounds), and heat exchangers. Thermomechanical conversion machines, such as ac motors and rotating volumetric motors are discussed. A system is recommended for the use of solar energy for irrigation and pumping in remote areas. Other applications include the production of cold of fresh water from brackish waters, and energy recovery from hot springs.

Proceedings of the AMEDD Clinical Psychology Short Course Held at San Francisco, California on 4-8 March 1985.

DTIC Science & Technology

1985-03-01

133 Intermediate solutions and Expanding Roles 0 CPT Fred N. Garland, Ph.D. Psychological Aspects of Terrorism: Terrorist groups and Personnel 141 MAJ...Robert P. O’Brien, Ph.D. The Psychological Aspects of Terrorism 155 MAJ Robert J. Rankin, Ph.D. A Factor-analytic Study of Deployment Attitudes of the...Kinesthetic Disassociation Technique in the 331 Treatment of Post-Traumatic Stress Disorder CPT Jean P. Wycoff, Ph.D. Behavioral Management of Chronic

Heavy Duty Roots Expander Heat Energy Recovery (HD-REHER)

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

Subramanian, Swami

2015-10-01

Eaton Corporation proposed a comprehensive project to develop and demonstrate advanced component technology that will reduce the cost of implementing Organic Rankine Cycle (ORC) Waste Heat Recovery (WHR) systems to Heavy-Duty Diesel engines, making adaptation of this fuel efficiency improving technology more commercially attractive to end-users in the next 5 to 10 year time period. Accelerated adaptation and implementation of new fuel efficiency technology into service is critical for reduction of fuel used in the commercial vehicle segment.

Materials compatibility issues related to thermal energy storage for a space solar dynamic power system

NASA Technical Reports Server (NTRS)

Faget, N. M.

1986-01-01

Attention is given to results obtained to date in developmental investigations of a thermal energy storage (TES) system for the projected NASA Space Station's solar dynamic power system; these tests have concentrated on issues related to materials compatibility for phase change materials (PCMs) and their containment vessels' materials. The five PCMs tested have melting temperatures that correspond to the operating temperatures of either the Brayton or Rankine heat engines, which were independently chosen for their high energy densities.

Conversion of Low Quality Waste Heat to Electric Power with Small-Scale Organic Rankine Cycle (ORC) Engine/Generator Technology

DTIC Science & Technology

2016-06-01

Allan Robichaux, DPW PWD GTMO and the management and staff of the GTMO on site contractor , Centerra. Page Intentionally Left Blank ii Table of...operations and maintenance contractor to ensure that data transfers are completed as required. Figure 4 shows the location of the ORC installation on MUSE...this issue with telephone support from CRM’s controls contractor (Winn-Marion, W-M); however, the problem remained unresolved as of Sept. 1 when

Optimum dry-cooling sub-systems for a solar air conditioner

NASA Technical Reports Server (NTRS)

Chen, J. L. S.; Namkoong, D.

1978-01-01

Dry-cooling sub-systems for residential solar powered Rankine compression air conditioners were economically optimized and compared with the cost of a wet cooling tower. Results in terms of yearly incremental busbar cost due to the use of dry-cooling were presented for Philadelphia and Miami. With input data corresponding to local weather, energy rate and capital costs, condenser surface designs and performance, the computerized optimization program yields design specifications of the sub-system which has the lowest annual incremental cost.

Ejector-turbine studies and experimental data. Final report, August 1, 1979-October 31, 1982

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

Minardi, J.E.; Lawson, M.O.; Krolak, R.V.

1982-11-01

An innovative low-power Rankine turbine concept is described which promises competitive efficiencies, low cost, significant reduction in rpm, low maintenance, and long-life operation over similarly rated turbines. The cycle uses a highly efficient two-fluid ejector which greatly lowers the turbine inlet pressure and temperature. The two-fluid ejector cycle is shown by theoretical studies to be capable of transferring energy at efficiencies in excess of 90% from a high-power flux fluid medium to a low-power flux fluid medium. The volume flow of the thermodynamic fluid can be augmented by as much as one-hundred fold. For very low-power turbine applications this couldmore » result in far-more-favorable turbine sizes and rpm. One major application for this type turbine is the heating and cooling with heat pumps. The concept permits engine cycles that cover an extremely broad range of peak temperatures, including those corresponding to stoichiometric combustion of hydrocarbon fuels, waste heat sources, and solar. Actual test data indicated ejector efficiencies as high as 85%. A two-fluid, ejector turbine was designed and tested. The turbine achieved 94% of design power. Additional data indicated that the ejector attached to the turbine operated on the supersonic branch.« less

Multi-megawatt power system trade study

NASA Astrophysics Data System (ADS)

Longhurst, Glen R.; Schnitzler, Bruce G.; Parks, Benjamin T.

2002-01-01

A concept study was undertaken to evaluate potential multi-megawatt power sources for nuclear electric propulsion. The nominal electric power requirement was set at 15 MWe with an assumed mission profile of 120 days at full power, 60 days in hot standby, and another 120 days of full power, repeated several times for 7 years of service. Two configurations examined were (1) a gas-cooled reactor based on the NERVA Derivative design, operating a closed cycle Brayton power conversion system; and (2) a molten metal-cooled reactor based on SP-100 technology, driving a boiling potassium Rankine power conversion system. This study considered the relative merits of these two systems, seeking to optimize the specific mass. Conclusions were that either concept appeared capable of reaching the specific mass goal of 3-5 kg/kWe estimated to be needed for this class of mission, though neither could be realized without substantial development in reactor fuels technology, thermal radiator mass and volume efficiency, and power conversion and distribution electronics and systems capable of operating at high temperatures. The gas-Brayton system showed a specific mass advantage (3.17 vs 6.43 kg/kWe for the baseline cases) under the set of assumptions used and eliminated the need to deal with two-phase working fluid flows in the microgravity environment of space. .

Diesels in combined cycle

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

Kuehn, S.E.

1995-03-01

This article examines why the diesel engine is a very attractive choice for producing power in the combined-cycle configuration. The medium-speed diesel is already one of the most efficient simple cycle sources of electricity, especially with lower grade fuels. Large units have heat-rate efficiencies as high as 45%, equating to a heat rate of 7,580 Btu/k Whr, and no other power production prime mover can match this efficiency. Diesels also offer designers fuel flexibility and can burn an extreme variety of fuels without sacrificing many of its positive operating attributes. Diesels are the first building block in a highly efficientmore » combined cycle system that relies on the hot gas and oxygen in the diesel`s exhaust to combust either natural gas, light distillate oil, heavy oil or coal, in a boiler. By using a fired boiler, steam can be generated at sufficient temperature and pressure to operate a Rankine steam cycle efficiently. Diesel combined-cycle plants can be configured in much the same way a gas turbine plant would be. However, the diesel combined-cycle scheme requires supplemental firing to generate appropriate steam conditions. The most efficient cycle, therefore, would not be achieved until combustion air and supplemental fuel are minimized to levels that satisfy steam conditions, steam generation and power generation constraints.« less

Making the Most of Waste Energy

NASA Technical Reports Server (NTRS)

2005-01-01

The Thermo-Mechanical Systems Branch at NASA s Glenn Research Center is responsible for planning and conducting research efforts to advance thermal systems for space, aerospace, and non-aerospace applications. Technological areas pertain to solar and thermal energy conversion. For example, thermo-mechanical systems researchers work with gas (Stirling) and liquid/vapor (Rankine) systems that convert thermal energy to electrical power, as well as solar dynamic power systems that concentrate sunlight to electrical power. The branch s development of new solar and thermal energy technologies is propelling NASA s missions deep into unfamiliar territories of space. Solar dynamic power systems are actively improving the health of orbiting satellites, giving them longer life and a stronger radiation tolerance, thus, creating less need for on-orbit maintenance. For future missions, NASA may probe even deeper into the mysterious cosmos, with the adoption of highly efficient thermal energy converters that have the potential to serve as the source of onboard electrical power for satellites and spacecraft. Research indicates that these thermal converters can deliver up to 5 times as much power as radioisotope thermoelectric generators in use today, for the same amount of radioisotope. On Earth, energy-converting technologies associated with NASA s Thermo-Mechanical Systems Branch are being used to recover and transform low-temperature waste heat into usable electric power, with a helping hand from NASA.

Shock compression modeling of metallic single crystals: comparison of finite difference, steady wave, and analytical solutions

DOE PAGES

Lloyd, Jeffrey T.; Clayton, John D.; Austin, Ryan A.; ...

2015-07-10

Background: The shock response of metallic single crystals can be captured using a micro-mechanical description of the thermoelastic-viscoplastic material response; however, using a such a description within the context of traditional numerical methods may introduce a physical artifacts. Advantages and disadvantages of complex material descriptions, in particular the viscoplastic response, must be framed within approximations introduced by numerical methods. Methods: Three methods of modeling the shock response of metallic single crystals are summarized: finite difference simulations, steady wave simulations, and algebraic solutions of the Rankine-Hugoniot jump conditions. For the former two numerical techniques, a dislocation density based framework describes themore » rate- and temperature-dependent shear strength on each slip system. For the latter analytical technique, a simple (two-parameter) rate- and temperature-independent linear hardening description is necessarily invoked to enable simultaneous solution of the governing equations. For all models, the same nonlinear thermoelastic energy potential incorporating elastic constants of up to order 3 is applied. Results: Solutions are compared for plate impact of highly symmetric orientations (all three methods) and low symmetry orientations (numerical methods only) of aluminum single crystals shocked to 5 GPa (weak shock regime) and 25 GPa (overdriven regime). Conclusions: For weak shocks, results of the two numerical methods are very similar, regardless of crystallographic orientation. For strong shocks, artificial viscosity affects the finite difference solution, and effects of transverse waves for the lower symmetry orientations not captured by the steady wave method become important. The analytical solution, which can only be applied to highly symmetric orientations, provides reasonable accuracy with regards to prediction of most variables in the final shocked state but, by construction, does not provide insight into the shock structure afforded by the numerical methods.« less

Bilateral robotic priming before task-oriented approach in subacute stroke rehabilitation: a pilot randomized controlled trial.

PubMed

Hsieh, Yu-Wei; Wu, Ching-Yi; Wang, Wei-En; Lin, Keh-Chung; Chang, Ku-Chou; Chen, Chih-Chi; Liu, Chien-Ting

2017-02-01

To investigate the treatment effects of bilateral robotic priming combined with the task-oriented approach on motor impairment, disability, daily function, and quality of life in patients with subacute stroke. A randomized controlled trial. Occupational therapy clinics in medical centers. Thirty-one subacute stroke patients were recruited. Participants were randomly assigned to receive bilateral priming combined with the task-oriented approach (i.e., primed group) or to the task-oriented approach alone (i.e., unprimed group) for 90 minutes/day, 5 days/week for 4 weeks. The primed group began with the bilateral priming technique by using a bimanual robot-aided device. Motor impairments were assessed by the Fugal-Meyer Assessment, grip strength, and the Box and Block Test. Disability and daily function were measured by the modified Rankin Scale, the Functional Independence Measure, and actigraphy. Quality of life was examined by the Stroke Impact Scale. The primed and unprimed groups improved significantly on most outcomes over time. The primed group demonstrated significantly better improvement on the Stroke Impact Scale strength subscale ( p = 0.012) and a trend for greater improvement on the modified Rankin Scale ( p = 0.065) than the unprimed group. Bilateral priming combined with the task-oriented approach elicited more improvements in self-reported strength and disability degrees than the task-oriented approach by itself. Further large-scale research with at least 31 participants in each intervention group is suggested to confirm the study findings.

Ion Upwelling and Height-Resolved Electrodynamic Response of the Ionosphere to ULF Waves and Precipitation: Comparison Between Simulation and EISCAT Observations

NASA Astrophysics Data System (ADS)

Sydorenko, D.; Rankin, R.

2013-12-01

We have developed a comprehensive two-dimensional (meridional) model of coupling between the magnetosphere and ionosphere that covers an altitude range from ~100 km to few thousand km at high latitudes [Sydorenko and Rankin, 2013]. The model describes propagation of inertial scale Alfven waves, including ponderomotive forces, and has a parametric model of energetic electron precipitation; it includes vertical ion flows and chemical reactions between ions and neutrals. Model results are presented that reproduce EISCAT radar observations of electron and ion temperatures, height integrated conductivity, ion densities, and ion flows during a period of ULF activity described in [Lester, Davies, and Yeoman, 2000]. We performed simulations where the precipitation and the Alfven wave perturb the ionosphere simultaneously. By adjusting parameters of the wave and the precipitation we have achieved qualitative, and sometimes even reasonable quantitative agreement between the observations and the simulation. The model results are discussed in the context of new results anticipated from the Canadian small satellite mission ePOP "Enhanced Polar Outflow Probe", scheduled for launch on September 9, 2013. Sydorenko D. and R. Rankin, 'Simulation of O+ upflows created by electron precipitation and Alfvén waves in the ionosphere' submitted to Journal of Geophysical Research, 2013. Lester M., J. A. Davies, and T. K. Yeoman, 'The ionospheric response during an interval of PC5 ULF wave activity', Ann. Geophysicae, v.18, p.257-261 (2000).

Impact of Transcranial Doppler Ultrasound on Logistics and Outcomes in Stroke Thrombolysis: Results From the SITS-ISTR.

PubMed

Mazya, Michael V; Ahmed, Niaz; Azevedo, Elsa; Davalos, Antoni; Dorado, Laura; Karlinski, Michal; Lorenzano, Svetlana; Neumann, Jiří; Toni, Danilo; Moreira, Tiago P

2018-07-01

Diagnostic transcranial Doppler ultrasound (TCD) is commonly used in patients with acute stroke before or during treatment with intravenous thrombolysis (IVT). We aimed to assess how much TCD delays IVT initiation and whether TCD influences outcomes. We analyzed data from the SITS-ISTR (Safe Implementation of Thrombolysis in Stroke-International Stroke Thrombolysis Register) collected from December 2002 to December 2011. Outcomes were door-to-needle time, symptomatic intracerebral hemorrhage, functional outcome per the modified Rankin Scale, and mortality at 3 months. In hospitals performing any TCD pre-IVT, 1701 of 11 265 patients (15%) had TCD before IVT initiation. Door-to-needle time was higher in patients with pre-IVT TCD (74 versus 60 minutes; P <0.001). At hospitals performing any TCD during IVT infusion, of 9044 patients with IVT, 747 were examined with TCD during IVT. No treatment delay was seen with TCD during IVT. After multivariate adjustment, TCD during IVT was independently associated with modestly increased excellent functional outcome (modified Rankin Scale, 0-1; adjusted odds ratio, 1.28; 95% confidence interval, 1.06-1.55; P =0.012) and lower mortality (adjusted odds ratio, 0.73; 95% confidence interval, 0.55-0.95; P =0.022). We recommend that TCD, if performed, should be done during IVT infusion, to avoid treatment delay. The association of hyperacute TCD with beneficial outcomes suggests potential impact on patient management, which warrants further study. © 2018 American Heart Association, Inc.

Automated Detection and Analysis of Interplanetary Shocks with Real-Time Application

NASA Astrophysics Data System (ADS)

Vorotnikov, V.; Smith, C. W.; Hu, Q.; Szabo, A.; Skoug, R. M.; Cohen, C. M.

2006-12-01

The ACE real-time data stream provides web-based now-casting capabilities for solar wind conditions upstream of Earth. Our goal is to provide an automated code that finds and analyzes interplanetary shocks as they occur for possible real-time application to space weather nowcasting. Shock analysis algorithms based on the Rankine-Hugoniot jump conditions exist and are in wide-spread use today for the interactive analysis of interplanetary shocks yielding parameters such as shock speed and propagation direction and shock strength in the form of compression ratios. Although these codes can be automated in a reasonable manner to yield solutions not far from those obtained by user-directed interactive analysis, event detection presents an added obstacle and the first step in a fully automated analysis. We present a fully automated Rankine-Hugoniot analysis code that can scan the ACE science data, find shock candidates, analyze the events, obtain solutions in good agreement with those derived from interactive applications, and dismiss false positive shock candidates on the basis of the conservation equations. The intent is to make this code available to NOAA for use in real-time space weather applications. The code has the added advantage of being able to scan spacecraft data sets to provide shock solutions for use outside real-time applications and can easily be applied to science-quality data sets from other missions. Use of the code for this purpose will also be explored.

Coadjuvant Treatment of Vasospasm in Ruptured Unsecured Cerebral Aneurysms with Aggressive Angioplasty, Intra-Arterial Nimodipine, and Aneurysm Embolization.

PubMed

Chen, Ching-Chang; Yi-Chou Wang, Alvin; Chen, Chun-Ting; Hsieh, Po-Chuan

2018-05-16

Vasospasm is a major cause of morbidity and mortality in patients after aneurysmal subarachnoid hemorrhage. Early treatment of ruptured aneurysms is advocated; delayed intervention complicates the treatment strategy leading to significant vasospasm and poor prognosis. We report an endovascular protocol for occlusion of the unsecured aneurysm and angioplasty for vasospasm in a single session. Between January 2011 and May 2017, among 660 patients with aneurysmal subarachnoid hemorrhage, 24 patients with significant vasospasm and unsecured ruptured cerebral aneurysm were reviewed. Continuous nimodipine drip through a pressure line of the guiding catheter was set up. Aggressive angioplasty with a compliant balloon catheter either before or after embolization of the aneurysm in the major branches of vasospastic territory was performed. The goal was complete embolization of the aneurysm. Of 24 patients, 17 had ischemic symptoms at presentation, and the average delay from aneurysm rupture to presentation was 7.58 days. Angioplasty and nimodipine drip were performed on all patients. Severity of vasospasm was significantly reduced, and outcome improved in each patient. Two patients required a second angioplasty. In 20 patients, embolization of aneurysms was achieved without any aneurysmal sac or residual neck. Clinical outcome was good recovery (modified Rankin Scale score 0-2) in 23 patients (95.8%) and moderate disability in 1 patient (modified Rankin Scale score 3). Aggressive endovascular treatment of patients with unsecured ruptured cerebral aneurysm and associated vasospasm is safe and effective. Copyright © 2018 Elsevier Inc. All rights reserved.

High-temperature solar receiver integrated with a short-term storage system

NASA Astrophysics Data System (ADS)

Giovannelli, Ambra; Bashir, Muhammad Anser; Archilei, Erika Maria

2017-06-01

Small-Scale Concentrated Solar Power Plants could have a potential market for off-grid applications in rural contexts with limited access to the electrical grid and favorable environmental characteristics. Some Small-Scale plants have already been developed, like the 25-30 kWe Dish-Stirling engine. Other ones are under development as, for example, plants based on Parabolic Trough Collectors coupled with Organic Rankine Cycles. Furthermore, the technological progress achieved in the development of new small high-temperature solar receiver, makes possible the development of interesting systems based on Micro Gas Turbines coupled with Dish collectors. Such systems could have several advantages in terms of costs, reliability and availability if compared with Dish-Stirling plants. In addition, Dish-Micro Gas Turbine systems are expected to have higher performance than Solar Organic Rankine Cycle plants. The present work focuses the attention on some challenging aspects related to the design of small high-temperature solar receivers for Dish-Micro Gas Turbine systems. Natural fluctuations in the solar radiation can reduce system performance and damage seriously the Micro Gas Turbine. To stabilize the system operation, the solar receiver has to assure a proper thermal inertia. Therefore, a solar receiver integrated with a short-term storage system based on high-temperature phase-change materials is proposed in this paper. Steady-state and transient analyses (for thermal storage charge and discharge phases) have been carried out using the commercial CFD code Ansys-Fluent. Results are presented and discussed.

The Relationship Between Serum Neuron-Specific Enolase Levels and Severity of Bleeding and Functional Outcomes in Patients With Nontraumatic Subarachnoid Hemorrhage.

PubMed

Tawk, Rabih G; Grewal, Sanjeet S; Heckman, Michael G; Rawal, Bhupendra; Miller, David A; Edmonston, Drucilla; Ferguson, Jennifer L; Navarro, Ramon; Ng, Lauren; Brown, Benjamin L; Meschia, James F; Freeman, William D

2016-04-01

The value of neuron-specific enolase (NSE) in predicting clinical outcomes has been investigated in a variety of neurological disorders. To investigate the associations of serum NSE with severity of bleeding and functional outcomes in patients with subarachnoid hemorrhage (SAH). We retrospectively reviewed the records of patients with SAH from June 2008 to June 2012. The severity of SAH bleeding at admission was measured radiographically with the Fisher scale and clinically with the Glasgow Coma Scale, Hunt and Hess grade, and World Federation of Neurologic Surgeons scale. Outcomes were assessed with the modified Rankin Scale at discharge. We identified 309 patients with nontraumatic SAH, and 71 had NSE testing. Median age was 54 years (range, 23-87 years), and 44% were male. In multivariable analysis, increased NSE was associated with a poorer Hunt and Hess grade (P = .003), World Federation of Neurologic Surgeons scale score (P < .001), and Glasgow Coma Scale score (P = .003) and worse outcomes (modified Rankin Scale at discharge; P = .001). There was no significant association between NSE level and Fisher grade (P = .81) in multivariable analysis. We found a significant association between higher NSE levels and poorer clinical presentations and worse outcomes. Although it is still early for any relevant clinical conclusions, our results suggest that NSE holds promise as a tool for screening patients at increased risk of poor outcomes after SAH.

Parametric and working fluid analysis of a combined organic Rankine-vapor compression refrigeration system activated by low-grade thermal energy.

PubMed

Saleh, B

2016-09-01

The potential use of many common hydrofluorocarbons and hydrocarbons as well as new hydrofluoroolefins, i.e. R1234yf and R1234ze(E) working fluids for a combined organic Rankine cycle and vapor compression refrigeration (ORC-VCR) system activated by low-grade thermal energy is evaluated. The basic ORC operates between 80 and 40 °C typical for low-grade thermal energy power plants while the basic VCR cycle operates between 5 and 40 °C. The system performance is characterized by the overall system coefficient of performance (COPS) and the total mass flow rate of the working fluid for each kW cooling capacity ([Formula: see text]). The effects of different working parameters such as the evaporator, condenser, and boiler temperatures on the system performance are examined. The results illustrate that the maximum COPS values are attained using the highest boiling candidates with overhanging T-s diagram, i.e. R245fa and R600, while R600 has the lowest [Formula: see text] under the considered operating conditions. Among the proposed candidates, R600 is the best candidate for the ORC-VCR system from the perspectives of environmental issues and system performance. Nevertheless, its flammability should attract enough attention. The maximum COPS using R600 is found to reach up to 0.718 at a condenser temperature of 30 °C and the basic values for the remaining parameters.

Aortic stiffness predicts functional outcome in patients after ischemic stroke.

PubMed

Gasecki, Dariusz; Rojek, Agnieszka; Kwarciany, Mariusz; Kubach, Marlena; Boutouyrie, Pierre; Nyka, Walenty; Laurent, Stephane; Narkiewicz, Krzysztof

2012-02-01

Increased aortic stiffness (measured by carotid-femoral pulse wave velocity) and central augmentation index have been shown to independently predict cardiovascular events, including stroke. We studied whether pulse wave velocity and central augmentation index predict functional outcome after ischemic stroke. In a prospective study, we enrolled 99 patients with acute ischemic stroke (age 63.7 ± 12.4 years, admission National Institutes of Health Stroke Scale score 6.6 ± 6.6, mean ± SD). Carotid-femoral pulse wave velocity and central augmentation index (SphygmoCor) were measured 1 week after stroke onset. Functional outcome was evaluated 90 days after stroke using the modified Rankin Scale with modified Rankin Scale score of 0 to 1 considered an excellent outcome. In univariate analysis, low carotid-femoral pulse wave velocity (P=0.000001) and low central augmentation index (P=0.028) were significantly associated with excellent stroke outcome. Age, severity of stroke, presence of previous stroke, diabetes, heart rate, and peripheral pressures also predicted stroke functional outcome. In multivariate analysis, the predictive value of carotid-femoral pulse wave velocity (<9.4 m/s) remained significant (OR, 0.21; 95% CI, 0.06-0.79; P=0.02) after adjustment for age, National Institutes of Health Stroke Scale score on admission, and presence of previous stroke. By contrast, central augmentation index had no significant predictive value after adjustment. This study indicates that aortic stiffness is an independent predictor of functional outcome in patients with acute ischemic stroke.

Hydrodynamic Simulations of Ejecta Production From Shocked Metallic Surfaces

NASA Astrophysics Data System (ADS)

Karkhanis, Varad Abhimanyu

The phenomenon of mass ejection into vacuum from a shocked metallic free surfaces can have a deleterious effect on the implosion phase of the Inertial Confinement Fusion (ICF) process. Often, the ejecta take the form of a cloud of particles that are the result of microjetting sourced from imperfections on the metallic free surface. Significant progress has been achieved in the understanding of ejecta dynamics by treating the process as a limiting case of the baroclinically-driven Richtmyer-Meshkov Instability (RMI). This conceptual picture is complicated by several practical considerations including breakup of spikes due to surface tension and yield strength of the metal. Thus, the problem involves a wide range of physical phenomena, occurring often under extreme conditions of material behavior. We describe an approach in which continuum simulations using ideal gases can be used to capture key aspects of ejecta growth associated with the RMI. The approach exploits the analogy between the Rankine-Hugoniot jump conditions for ideal gases and the linear relationship between the shock velocity and particle velocity governing shocked metals. Such simulations with Upsilon-law fluids have been successful in accurately predicting the velocity and mass of ejecta for different shapes, and in excellent agreement with experiments. We use the astrophysical FLASH code, developed at the University of Chicago to model this problem. Based on insights from our simulations, we suggest a modified expression for ejecta velocities that is valid for large initial perturbation amplitudes. The expression for velocities is extended to ejecta originating from cavities with any arbitrary shape. The simulations are also used to validate a recently proposed source model for ejecta that predicts the ejected mass per unit area for sinusoidal and non-standard shapes. Such simulations and theoretical models play an important role in the design of target experiment campaigns.

Cluster-Randomized, Crossover Trial of Head Positioning in Acute Stroke.

PubMed

Anderson, Craig S; Arima, Hisatomi; Lavados, Pablo; Billot, Laurent; Hackett, Maree L; Olavarría, Verónica V; Muñoz Venturelli, Paula; Brunser, Alejandro; Peng, Bin; Cui, Liying; Song, Lily; Rogers, Kris; Middleton, Sandy; Lim, Joyce Y; Forshaw, Denise; Lightbody, C Elizabeth; Woodward, Mark; Pontes-Neto, Octavio; De Silva, H Asita; Lin, Ruey-Tay; Lee, Tsong-Hai; Pandian, Jeyaraj D; Mead, Gillian E; Robinson, Thompson; Watkins, Caroline

2017-06-22

The role of supine positioning after acute stroke in improving cerebral blood flow and the countervailing risk of aspiration pneumonia have led to variation in head positioning in clinical practice. We wanted to determine whether outcomes in patients with acute ischemic stroke could be improved by positioning the patient to be lying flat (i.e., fully supine with the back horizontal and the face upwards) during treatment to increase cerebral perfusion. In a pragmatic, cluster-randomized, crossover trial conducted in nine countries, we assigned 11,093 patients with acute stroke (85% of the strokes were ischemic) to receive care in either a lying-flat position or a sitting-up position with the head elevated to at least 30 degrees, according to the randomization assignment of the hospital to which they were admitted; the designated position was initiated soon after hospital admission and was maintained for 24 hours. The primary outcome was degree of disability at 90 days, as assessed with the use of the modified Rankin scale (scores range from 0 to 6, with higher scores indicating greater disability and a score of 6 indicating death). The median interval between the onset of stroke symptoms and the initiation of the assigned position was 14 hours (interquartile range, 5 to 35). Patients in the lying-flat group were less likely than patients in the sitting-up group to maintain the position for 24 hours (87% vs. 95%, P<0.001). In a proportional-odds model, there was no significant shift in the distribution of 90-day disability outcomes on the global modified Rankin scale between patients in the lying-flat group and patients in the sitting-up group (unadjusted odds ratio for a difference in the distribution of scores on the modified Rankin scale in the lying-flat group, 1.01; 95% confidence interval, 0.92 to 1.10; P=0.84). Mortality within 90 days was 7.3% among the patients in the lying-flat group and 7.4% among the patients in the sitting-up group (P=0.83). There were no significant between-group differences in the rates of serious adverse events, including pneumonia. Disability outcomes after acute stroke did not differ significantly between patients assigned to a lying-flat position for 24 hours and patients assigned to a sitting-up position with the head elevated to at least 30 degrees for 24 hours. (Funded by the National Health and Medical Research Council of Australia; HeadPoST ClinicalTrials.gov number, NCT02162017 .).

Low-Dose versus Standard-Dose Intravenous Alteplase in Acute Ischemic Stroke.

PubMed

Anderson, Craig S; Robinson, Thompson; Lindley, Richard I; Arima, Hisatomi; Lavados, Pablo M; Lee, Tsong-Hai; Broderick, Joseph P; Chen, Xiaoying; Chen, Guofang; Sharma, Vijay K; Kim, Jong S; Thang, Nguyen H; Cao, Yongjun; Parsons, Mark W; Levi, Christopher; Huang, Yining; Olavarría, Verónica V; Demchuk, Andrew M; Bath, Philip M; Donnan, Geoffrey A; Martins, Sheila; Pontes-Neto, Octavio M; Silva, Federico; Ricci, Stefano; Roffe, Christine; Pandian, Jeyaraj; Billot, Laurent; Woodward, Mark; Li, Qiang; Wang, Xia; Wang, Jiguang; Chalmers, John

2016-06-16

Thrombolytic therapy for acute ischemic stroke with a lower-than-standard dose of intravenous alteplase may improve recovery along with a reduced risk of intracerebral hemorrhage. Using a 2-by-2 quasi-factorial open-label design, we randomly assigned 3310 patients who were eligible for thrombolytic therapy (median age, 67 years; 63% Asian) to low-dose intravenous alteplase (0.6 mg per kilogram of body weight) or the standard dose (0.9 mg per kilogram); patients underwent randomization within 4.5 hours after the onset of stroke. The primary objective was to determine whether the low dose would be noninferior to the standard dose with respect to the primary outcome of death or disability at 90 days, which was defined by scores of 2 to 6 on the modified Rankin scale (range, 0 [no symptoms] to 6 [death]). Secondary objectives were to determine whether the low dose would be superior to the standard dose with respect to centrally adjudicated symptomatic intracerebral hemorrhage and whether the low dose would be noninferior in an ordinal analysis of modified Rankin scale scores (testing for an improvement in the distribution of scores). The trial included 935 patients who were also randomly assigned to intensive or guideline-recommended blood-pressure control. The primary outcome occurred in 855 of 1607 participants (53.2%) in the low-dose group and in 817 of 1599 participants (51.1%) in the standard-dose group (odds ratio, 1.09; 95% confidence interval [CI], 0.95 to 1.25; the upper boundary exceeded the noninferiority margin of 1.14; P=0.51 for noninferiority). Low-dose alteplase was noninferior in the ordinal analysis of modified Rankin scale scores (unadjusted common odds ratio, 1.00; 95% CI, 0.89 to 1.13; P=0.04 for noninferiority). Major symptomatic intracerebral hemorrhage occurred in 1.0% of the participants in the low-dose group and in 2.1% of the participants in the standard-dose group (P=0.01); fatal events occurred within 7 days in 0.5% and 1.5%, respectively (P=0.01). Mortality at 90 days did not differ significantly between the two groups (8.5% and 10.3%, respectively; P=0.07). This trial involving predominantly Asian patients with acute ischemic stroke did not show the noninferiority of low-dose alteplase to standard-dose alteplase with respect to death and disability at 90 days. There were significantly fewer symptomatic intracerebral hemorrhages with low-dose alteplase. (Funded by the National Health and Medical Research Council of Australia and others; ENCHANTED ClinicalTrials.gov number, NCT01422616.).

Thermodynamic and design considerations of organic Rankine cycles in combined application with a solar thermal gas turbine

NASA Astrophysics Data System (ADS)

Braun, R.; Kusterer, K.; Sugimoto, T.; Tanimura, K.; Bohn, D.

2013-12-01

Concentrated Solar Power (CSP) technologies are considered to provide a significant contribution for the electric power production in the future. Different kinds of technologies are presently in operation or under development, e.g. parabolic troughs, central receivers, solar dish systems and Fresnel reflectors. This paper takes the focus on central receiver technologies, where the solar radiation is concentrated by a field of heliostats in a receiver on the top of a tall tower. To get this CSP technology ready for the future, the system costs have to reduce significantly. The main cost driver in such kind of CSP technologies are the huge amount of heliostats. To reduce the amount of heliostats, and so the investment costs, the efficiency of the energy conversion cycle becomes an important issue. An increase in the cycle efficiency results in a decrease of the solar heliostat field and thus, in a significant cost reduction. The paper presents the results of a thermodynamic model of an Organic Rankine Cycle (ORC) for combined cycle application together with a solar thermal gas turbine. The gas turbine cycle is modeled with an additional intercooler and recuperator and is based on a typical industrial gas turbine in the 2 MW class. The gas turbine has a two stage radial compressor and a three stage axial turbine. The compressed air is preheated within a solar receiver to 950°C before entering the combustor. A hybrid operation of the gas turbine is considered. In order to achieve a further increase of the overall efficiency, the combined operation of the gas turbine and an Organic Rankine Cycle is considered. Therefore an ORC has been set up, which is thermally connected to the gas turbine cycle at two positions. The ORC can be coupled to the solar-thermal gas turbine cycle at the intercooler and after the recuperator. Thus, waste heat from different cycle positions can be transferred to the ORC for additional production of electricity. Within this investigation different working fluids and ORC conditions have been analyzed in order to evaluate the best configuration. The investigations have been performed by application of improved thermodynamic and process analysis tools, which consider the real gas behavior of the analyzed fluids. The results show that by combined operation of the solar thermal gas turbine and the ORC, the combined cycle efficiency is approximately 4%-points higher than in the solar-thermal gas turbine cycle.

Thrombectomy 6 to 24 Hours after Stroke with a Mismatch between Deficit and Infarct.

PubMed

Nogueira, Raul G; Jadhav, Ashutosh P; Haussen, Diogo C; Bonafe, Alain; Budzik, Ronald F; Bhuva, Parita; Yavagal, Dileep R; Ribo, Marc; Cognard, Christophe; Hanel, Ricardo A; Sila, Cathy A; Hassan, Ameer E; Millan, Monica; Levy, Elad I; Mitchell, Peter; Chen, Michael; English, Joey D; Shah, Qaisar A; Silver, Frank L; Pereira, Vitor M; Mehta, Brijesh P; Baxter, Blaise W; Abraham, Michael G; Cardona, Pedro; Veznedaroglu, Erol; Hellinger, Frank R; Feng, Lei; Kirmani, Jawad F; Lopes, Demetrius K; Jankowitz, Brian T; Frankel, Michael R; Costalat, Vincent; Vora, Nirav A; Yoo, Albert J; Malik, Amer M; Furlan, Anthony J; Rubiera, Marta; Aghaebrahim, Amin; Olivot, Jean-Marc; Tekle, Wondwossen G; Shields, Ryan; Graves, Todd; Lewis, Roger J; Smith, Wade S; Liebeskind, David S; Saver, Jeffrey L; Jovin, Tudor G

2018-01-04

The effect of endovascular thrombectomy that is performed more than 6 hours after the onset of ischemic stroke is uncertain. Patients with a clinical deficit that is disproportionately severe relative to the infarct volume may benefit from late thrombectomy. We enrolled patients with occlusion of the intracranial internal carotid artery or proximal middle cerebral artery who had last been known to be well 6 to 24 hours earlier and who had a mismatch between the severity of the clinical deficit and the infarct volume, with mismatch criteria defined according to age (<80 years or ≥80 years). Patients were randomly assigned to thrombectomy plus standard care (the thrombectomy group) or to standard care alone (the control group). The coprimary end points were the mean score for disability on the utility-weighted modified Rankin scale (which ranges from 0 [death] to 10 [no symptoms or disability]) and the rate of functional independence (a score of 0, 1, or 2 on the modified Rankin scale, which ranges from 0 to 6, with higher scores indicating more severe disability) at 90 days. A total of 206 patients were enrolled; 107 were assigned to the thrombectomy group and 99 to the control group. At 31 months, enrollment in the trial was stopped because of the results of a prespecified interim analysis. The mean score on the utility-weighted modified Rankin scale at 90 days was 5.5 in the thrombectomy group as compared with 3.4 in the control group (adjusted difference [Bayesian analysis], 2.0 points; 95% credible interval, 1.1 to 3.0; posterior probability of superiority, >0.999), and the rate of functional independence at 90 days was 49% in the thrombectomy group as compared with 13% in the control group (adjusted difference, 33 percentage points; 95% credible interval, 24 to 44; posterior probability of superiority, >0.999). The rate of symptomatic intracranial hemorrhage did not differ significantly between the two groups (6% in the thrombectomy group and 3% in the control group, P=0.50), nor did 90-day mortality (19% and 18%, respectively; P=1.00). Among patients with acute stroke who had last been known to be well 6 to 24 hours earlier and who had a mismatch between clinical deficit and infarct, outcomes for disability at 90 days were better with thrombectomy plus standard care than with standard care alone. (Funded by Stryker Neurovascular; DAWN ClinicalTrials.gov number, NCT02142283 .).

Role of vortices in cavitation formation in the flow across a mechanical heart valve.

PubMed

Li, Chi-Pei; Lu, Po-Chien; Liu, Jia-Shing; Lo, Chi-Wen; Hwang, Ned H

2008-07-01

Cavitation occurs during mechanical heart valve closure when the local pressure drops below vapor pressure. The formation of stable gas bubbles may result in gaseous emboli, and secondarily cause transient ischemic attacks or strokes. It is noted that instantaneous valve closure, occluder rebound and high-speed leakage flow generate vortices that promote low-pressure regions in favor of stable bubble formation; however, to date no studies have been conducted for the quantitative measurement and analysis of these vortices. A Björk-Shiley Monostrut (BSM) monoleaflet valve was placed in the mitral position of a pulsatile mock circulatory loop. Particle image velocimetry (PIV) and pico coulomb (PCB) pressure measurements were applied. Flow field measurements were carried out at t = -5, -3, -1, -0.5, 0 (valve closure), 0.3, 0.5, 0.75, 1.19, 1.44, 1.69, 1.94, 2, 2.19, 2.54, 2.79, 3.04, 3.29, 3.54, 5 and 10 ms. The vortices were quantitatively analyzed using the Rankine vortex model. A single counter-clockwise vortex was The instantaneous formation of cavitation bubbles at mechanical heart valve (MHV) closure, which subsequently damage blood cells and valve integrity, is a well-known and widely studied phenomenon (1-4). Contributing factors seem to include the water-hammer, squeeze flow and Venturi effects, all of which are short-lived. Both, Dauzat et al. (5) and Sliwka et al. (6) have detected high-intensity transient signals (HITS) with transcranial Doppler ultrasound in the carotid and cerebral arteries of MHV recipients, while Deklunder (7) observed clinical occurrences of cerebral gas emboli that were not seen with bioprosthetic valves. These detected over the major orifice, while a pair of counter-rotating vortices was found over the minor orifice. Velocity profiles were consistent with Rankine vortices. The vortex strength and magnitude of the pressure drop peaked shortly after initial occluder-housing impact and rapidly decreased after 0.5 ms, indicating viscous dissipation, with a less significant contribution from the occluder rebound effect. The maximum pressure drop was on the order of magnitude of 40 mmHg. Detailed PIV measurements and quantitative analysis of the BSM mechanical heart valve revealed large-scale vortex formation immediately after valve closure. Of note, the vortices were typical of a Rankine vortex and the maximum pressure change at the vortex center was only 40 mmHg. These data support the conclusion that vortex formation alone cannot generate the magnitude of pressure drop required for cavitation bubble formation.

Field verification of reconstructed dam-break flood, Laurel Run, Pennsylvania

USGS Publications Warehouse

Chen, Cheng-lung; Armbruster, Jeffrey T.

1979-01-01

A one-dimensional dam-break flood routing model is verified by using observed data on the flash flood resulting from the failure of Laurel Run Reservoir Dam near Johnstown, Pennsylvania. The model has been developed on the basis of an explicit scheme of the characteristics method with specified time intervals. The model combines one of the characteristic equations with the Rankine-Hugoniot shock equations to trace the corresponding characteristic backward to the known state for solving the depth and velocity of flow at the wave front. The previous version of the model has called for a modification of the method of solution to overcome the computational difficulty at the narrow breach and at any geomorphological constraints where channel geometry changes rapidly. The large reduction in the computational inaccuracies and oscillations was achieved by introducing the actual "storage width" in the equation of continuity and the imaginary "conveyance width" in the equation of motion. Close agreement between observed and computed peak stages at several stations downstream of the dam strongly suggests the validity and applicability of the model. However, small numerical noise appearing in the computed stage and discharge hydrographs at the dam site as well as discrepancy of attenuated peaks in the discharge hydrographs indicate the need for further model improvement.

Resuscitation Outcomes Consortium (ROC) PRIMED Cardiac Arrest Trial Methods, Part 1: Rationale and Methodology for the Impedance Threshold Device (ITD) Protocol

PubMed Central

Aufderheide, Tom P.; Kudenchuk, Peter J.; Hedges, Jerris R.; Nichol, Graham; Kerber, Richard E.; Dorian, Paul; Davis, Daniel P.; Idris, Ahamed H.; Callaway, Clifton W.; Emerson, Scott; Stiell, Ian G.; Terndrup, Thomas E.

2013-01-01

Aim The primary aim of this study is to compare survival to hospital discharge with a modified Rankin score (MRS) ≤3 between standard cardiopulmonary resuscitation (CPR) plus an active impedance threshold device (ITD) versus standard CPR plus a sham ITD in patients with out-of-hospital cardiac arrest. Secondary aims are to compare functional status and depression at discharge and at 3 and 6 months post discharge in survivors. Materials and Methods Design Prospective, double-blind, randomized, controlled, clinical trial. Population Patients with non-traumatic out-of-hospital cardiac arrest treated by emergency medical services (EMS) providers. Setting EMS systems participating in the Resuscitation Outcomes Consortium. Sample Size Based on a one-sided significance level of 0.025, power = 0.90, a survival with MRS ≤ 3 to discharge rate of 5.33% with standard CPR and sham ITD, and two interim analyses, a maximum of 14,742 evaluable patients are needed to detect a 6.69% survival with MRS ≤ 3 to discharge with standard CPR and active ITD (1.36% absolute survival difference). Conclusion If the ITD demonstrates the hypothesized improvement in survival, it is estimated that2,700 deaths from cardiac arrest per year would be averted in North America alone. PMID:18487005

Public Employee Free Speech; Is Rankin V. McPherson Still Alive?

DTIC Science & Technology

1991-05-10

eneally, M. Nimmer and L. Sobel, Niznmer on Freedom of Speech §4.08 (1989). M. Player, Employment Discrimination, §3.13 (1988). ~2ad 3 438 U.S. 378 (1987...908 F. 2d 1499, 1505 (11th Cir. 1990) (Public employee’s right to freedom of speech is not absolute. (ailing Bryson v. City of Waycross, 888 F.2d...the law of the first amendment has always been, by necessity, a law of flexibility. Public employee freedom of speech is no exception. 29 Seee.g

Cylinder wakes in flowing soap films

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

Vorobieff, P.; Ecke, R.E.; Vorobieff, P.

1999-09-01

We present an experimental characterization of cylinder wakes in flowing soap films. From instantaneous velocity and thickness fields, we find the vortex-shedding frequency, mean-flow velocity, and mean-film thickness. Using the empirical relationship between the Reynolds and Strouhal numbers obtained for cylinder wakes in three dimensions, we estimate the effective soap-film viscosity and its dependence on film thickness. We also compare the decay of vorticity with that in a simple Rankine vortex model with a dissipative term to account for air drag. [copyright] [ital 1999] [ital The American Physical Society

Oral Contraceptives Use by Young Woman Reduces Peak Bone Mass

DTIC Science & Technology

1999-09-01

Alphacel 10.0 Lard 5.20 Safflower Oil (linoleic) 1.00 Choline Bitartrate 0.20 Vitamin Mixture, AIN-76A 1.00 Mineral Mix, AIN-76 3.50 On Nov...774-9,1970 Modrowoski D, del Pozo E, Miravet L . Horm Metab Res 24(10):474-477, 1992. Parfitt AM, Drezner MK, Glorieux FH, et al. J Bone Mineral Res...Register.1 C. L . Hughes.*2 U. Blas- Machado.*1 E. Sulistiawati.*’ P. W. Louderback.*1 S. E. Rankin.*1 ’Pathology/Comparative Medicine, Wake Forest

Hermetic turbine generator

DOEpatents

Meacher, John S.; Ruscitto, David E.

1982-01-01

A Rankine cycle turbine drives an electric generator and a feed pump, all on a single shaft, and all enclosed within a hermetically sealed case. The shaft is vertically oriented with the turbine exhaust directed downward and the shaft is supported on hydrodynamic fluid film bearings using the process fluid as lubricant and coolant. The selection of process fluid, type of turbine, operating speed, system power rating, and cycle state points are uniquely coordinated to achieve high turbine efficiency at the temperature levels imposed by the recovery of waste heat from the more prevalent industrial processes.

Underwater gas tornado

NASA Astrophysics Data System (ADS)

Byalko, Alexey V.

2013-07-01

We present the first experimental observation of a new hydrodynamic phenomenon, the underwater tornado. Simple measurements show that the tornado forms a vortex of the Rankine type, i.e. the rising gas rotates as a solid body and the liquid rotates with a velocity decreasing hyperbolically with the radius. We obtain the dependence of the tornado radius a on the gas stream value j theoretically: a ∼ j2/5. Processing of a set of experiments yielded the value 0.36 for the exponent in this expression. We also report the initial stages of the theoretical study of this phenomenon.

Conversion of Low Quality Waste Heat to Electric Power with Small-Scale Organic Rankine Cycle (ORC) Engine/Generator Technology

DTIC Science & Technology

2016-08-01

REPORT DOCUMENTATION PAGE Form Approved OMB No. 0704-0188 The public reporting burden for this collection of information is estimated to average 1...urrendy valid OMB control number. PLEASE DO NOT RETURN YOUR FORM TO THE ABOVE ADDRESS. 1. REPORT DATE (DD-MM-YYYY) , 2. REPORT TYPE 3. DATES COVERED (From...NUMBER (Include area code) 919-282-1050 Standard Form 298 (Rev. 8198) Pntscnbed by ANSI Std. Z39.18 Cost & Performance Report 58XX i COST

Molten salt power towers operating at 600–650 °C: Salt selection and cost benefits

DOE PAGES

Turchi, Craig S.; Vidal, Judith; Bauer, Matthew

2018-03-14

This analysis examines the potential benefit of adopting the supercritical carbon dioxide (sCO 2) Brayton cycle at 600-650 degrees C compared to the current state-of-the-art power tower operating a steam-Rankine cycle with solar salt at approximately 574 degrees C. The analysis compares a molten-salt power tower configuration using direct storage of solar salt (60:40 wt% sodium nitrate: potassium nitrate) or single-component nitrate salts at 600 degrees C or alternative carbonate- or chloride-based salts at 650 degrees C.

The methodological features of studying energy efficiency of a combined mini-TPP on the basis of a gas-piston unit and a steam turbine

NASA Astrophysics Data System (ADS)

Shchinnikov, P. A.; Marasanov, N. V.

2017-07-01

The technology of electricity production by a mini-thermal power plant, operating on combined cycles of Otto and Rankine, is considered. The main aspects of the investigation methodology are outlined. It is shown that the design and layout parameters of all the major energy elements of the developed technology allow implementing it in a block and modular version; and the efficiency of electricity supply for the proposed technology will be at least 50 %.

GIRAPHE V3.3: A User’s Manual with Examples

DTIC Science & Technology

1988-09-13

less than one with a decimal (".15"). The correct usage is either to use a leading zero (Ŕ.15"), or to include at least one space or tab before the...where T. is the absolute temperature. The units for the temperature scale may be specified as Kelvin, Rankin, degrees Celsius, or degrees Fahrenheit...follow, so that the number should be represented with a preceding zero (i.e. Ŕ.49") instead. The data columns may be referred to in the GIRAPHE command

Energy Conversion Alternatives Study (ECAS), Westinghouse phase 1. Volume 1: Introduction and summary and general assumptions. [energy conversion systems for electric power plants using coal - feasibility

NASA Technical Reports Server (NTRS)

Beecher, D. T.

1976-01-01

Nine advanced energy conversion concepts using coal or coal-derived fuels are summarized. They are; (1) open-cycle gas turbines, (2) combined gas-steam turbine cycles, (3) closed-cycle gas turbines, (4) metal vapor Rankine topping, (5) open-cycle MHD; (6) closed-cycle MHD; (7) liquid-metal MHD; (8) advanced steam; and (9) fuel cell systems. The economics, natural resource requirements, and performance criteria for the nine concepts are discussed.

Biological and Behavioral Response Studies of Marine Mammals in Southern California, 2011 (SOCAL-11)

DTIC Science & Technology

2012-09-01

Hildebrand, C. Kyburg, R. Carlson, T. Yack, and J. Barlow ) EXECUTIVE SUMMARY PROJECT OBJECTIVES METHODOLOGY AND FOCAL SPECIES SOCAL-11...HYDROPHONE ARRAY. ( Tina M. Yack, Shannon Coates, Jay Barlow , John Calambokidis, Annie Douglas, and Shannon Rankin) INTRODUCTION MATERIALS AND...E. Falcone, G. Schorr, A. Douglas,  A. Stimpert, J. Hildebrand, C. Kyburg, R. Carlson, T. Yack, J.  Barlow        SOCAL‐11 PROJECT REPORT  2

Molten salt power towers operating at 600–650 °C: Salt selection and cost benefits

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

Turchi, Craig S.; Vidal, Judith; Bauer, Matthew

This analysis examines the potential benefit of adopting the supercritical carbon dioxide (sCO 2) Brayton cycle at 600-650 degrees C compared to the current state-of-the-art power tower operating a steam-Rankine cycle with solar salt at approximately 574 degrees C. The analysis compares a molten-salt power tower configuration using direct storage of solar salt (60:40 wt% sodium nitrate: potassium nitrate) or single-component nitrate salts at 600 degrees C or alternative carbonate- or chloride-based salts at 650 degrees C.

Rankine-Hugoniot relationships for molecular crystal explosives calculated using density functional theory based molecular dynamics

NASA Astrophysics Data System (ADS)

Mattsson, Ann E.; Wixom, Ryan R.; Mattsson, Thomas R.

2011-06-01

Density Functional Theory (DFT) has become a crucial tool for understanding the behavior of matter. The ability to perform high-fidelity calculations is most important for cases where experiments are impossible, dangerous, and/or prohibitively expensive to perform. For molecular crystals, successful use of DFT has been hampered by an inability to correctly describe the van der Waals' dominated equilibrium state. We have explored a way of bypassing this problem by using the Armiento-Mattsson 2005 (AM05) exchange-correlation functional. This functional is highly accurate for a wide range of solids, in particular in compression. Another advantage is that AM05 does not include any van der Waals' attraction. We will demonstrate the method on the PETN Hugoniot, and discuss our confidence in the results and ongoing research aimed at improvement. Sandia National Laboratories is a multi-program laboratory managed and operated by Sandia Corporation, a wholly owned subsidiary of Lockheed Martin Corporation, for the U.S. Department of Energy's National Nuclear Security Administration under contract DE-AC04-94AL85000.

Angiographic evaluation of the effect of intra-arterial milrinone therapy in patients with vasospasm from aneurysmal subarachnoid hemorrhage.

PubMed

Shankar, Jai Jai Shiva; dos Santos, Marlise P; Deus-Silva, Leonardo; Lum, Cheemun

2011-02-01

Several methods have been used to treat cerebral vasospasm, which is a major cause of morbidity and mortality in patients with aneurysmal subarachnoid hemorrhage (SAH). Here, we examined the effectiveness and safety of intra-arterial injection of milrinone for the treatment of vasospasm. Consecutive patients with angiographically confirmed vasospasm received intra-arterial milrinone between January 2006 and December 2007. The improvement in diameter of vessel (in millimeters) following treatment was assessed by paired t test for statistical significance. The angiographic improvement of supraclinoid internal carotid artery, M1 segment of middle cerebral artery, and A1 and A2 segment of anterior cerebral artery was compared with the modified Rankin score of the patients at discharge. A total of 15 milrinone treatments were performed in 14 patients (11 females and 3 males) with mean age of 52.7 years (31-68 years). There was significant angiographic improvement after milrinone therapy (p < 0.0001). Intra-arterial milrinone was a safe and effective treatment of cerebral vasospasm following aneurysmal SAH.

Robust optimization of supersonic ORC nozzle guide vanes

NASA Astrophysics Data System (ADS)

Bufi, Elio A.; Cinnella, Paola

2017-03-01

An efficient Robust Optimization (RO) strategy is developed for the design of 2D supersonic Organic Rankine Cycle turbine expanders. The dense gas effects are not-negligible for this application and they are taken into account describing the thermodynamics by means of the Peng-Robinson-Stryjek-Vera equation of state. The design methodology combines an Uncertainty Quantification (UQ) loop based on a Bayesian kriging model of the system response to the uncertain parameters, used to approximate statistics (mean and variance) of the uncertain system output, a CFD solver, and a multi-objective non-dominated sorting algorithm (NSGA), also based on a Kriging surrogate of the multi-objective fitness function, along with an adaptive infill strategy for surrogate enrichment at each generation of the NSGA. The objective functions are the average and variance of the isentropic efficiency. The blade shape is parametrized by means of a Free Form Deformation (FFD) approach. The robust optimal blades are compared to the baseline design (based on the Method of Characteristics) and to a blade obtained by means of a deterministic CFD-based optimization.

Dynamic Modeling of Solar Dynamic Components and Systems

NASA Technical Reports Server (NTRS)

Hochstein, John I.; Korakianitis, T.

1992-01-01

The purpose of this grant was to support NASA in modeling efforts to predict the transient dynamic and thermodynamic response of the space station solar dynamic power generation system. In order to meet the initial schedule requirement of providing results in time to support installation of the system as part of the initial phase of space station, early efforts were executed with alacrity and often in parallel. Initially, methods to predict the transient response of a Rankine as well as a Brayton cycle were developed. Review of preliminary design concepts led NASA to select a regenerative gas-turbine cycle using a helium-xenon mixture as the working fluid and, from that point forward, the modeling effort focused exclusively on that system. Although initial project planning called for a three year period of performance, revised NASA schedules moved system installation to later and later phases of station deployment. Eventually, NASA selected to halt development of the solar dynamic power generation system for space station and to reduce support for this project to two-thirds of the original level.

A Burst Mode, Ultrahigh Temperature UF4 Vapor Core Reactor Rankine Cycle Space Power System Concept

NASA Technical Reports Server (NTRS)

Dugan, E. T.; Kahook, S. D.; Diaz, N. J.

1996-01-01

Static and dynamic neutronic analyses have been performed on an innovative burst mode (100's of MW output for a few thousand seconds) Ulvahigh Temperature Vapor Core Reactor (UTVR) space nuclear power system. The NVTR employs multiple, neutronically-coupled fissioning cores and operates on a direct, closed Rankine cycle using a disk Magnetohydrodynamic (MHD) generater for energy conversion. The UTVR includes two types of fissioning core regions: (1) the central Ultrahigh Temperature Vapor Core (UTVC) which contains a vapor mixture of highly enriched UF4 fuel and a metal fluoride working fluid and (2) the UF4 boiler column cores located in the BeO moderator/reflector region. The gaseous nature of the fuel the fact that the fuel is circulating, the multiple coupled fissioning cores, and the use of a two phase fissioning fuel lead to unique static and dynamic neutronic characteristics. Static neutronic analysis was conducted using two-dimensional S sub n, transport theory calculations and three-dimensional Monte Carlo transport theory calculations. Circulating-fuel, coupled-core point reactor kinetics equations were used for analyzing the dynamic behavior of the UTVR. In addition to including reactivity feedback phenomena associated with the individual fissioning cores, the effects of core-to-core neutronic and mass flow coupling between the UTVC and the surrounding boiler cores were also included in the dynamic model The dynamic analysis of the UTVR reveals the existence of some very effectlve inherent reactivity feedback effects that are capable of quickly stabilizing this system, within a few seconds, even when large positive reactivity insertions are imposed. If the UTVC vapor fuel density feedback is suppressed, the UTVR is still inherently stable because of the boiler core liquid-fuel volume feedback; in contrast, suppression of the vapor fuel density feedback in 'conventional" gas core cavity reactors causes them to become inherently unstable. Due to the strength of the negative reactivity feedback in the UTVR, it is found that external reactivity insertions alone are inadequate for bringing about significant power level changes during normal reactor operations. Additional methods of reactivity control such as variations in the gaseous fuel mass flow rate, are needed to achieve the desired power level oontrol.

Trends in oral anticoagulant choice for acute stroke patients with nonvalvular atrial fibrillation in Japan: The SAMURAI‐NVAF Study

PubMed Central

Arihiro, Shoji; Todo, Kenichi; Yamagami, Hiroshi; Kimura, Kazumi; Furui, Eisuke; Terasaki, Tadashi; Shiokawa, Yoshiaki; Kamiyama, Kenji; Takizawa, Shunya; Okuda, Satoshi; Okada, Yasushi; Kameda, Tomoaki; Nagakane, Yoshinari; Hasegawa, Yasuhiro; Mochizuki, Hiroshi; Ito, Yasuhiro; Nakashima, Takahiro; Takamatsu, Kazuhiro; Nishiyama, Kazutoshi; Kario, Kazuomi; Sato, Shoichiro; Koga, Masatoshi; Nagatsuka, K; Minematsu, K; Nakagawara, J; Akiyama, H; Shibazaki, K; Maeda, K; Shibuya, S; Yoshimura, S; Endo, K; Miyagi, T; Osaki, M; Kobayashi, J; Okata, T; Tanaka, E; Sakamoto, Y; Takizawa, H; Takasugi, J; Tokunaga, K; Homma, K; Kinoshita, N; Matsuki, T; Higashida, K; Shiozawa, M; Kanai, H; Uehara, S

2015-01-01

Background Large clinical trials are lack of data on non‐vitamin K antagonist oral anticoagulants for acute stroke patients. Aim To evaluate the choice of oral anticoagulants at acute hospital discharge in stroke patients with nonvalvular atrial fibrillation and clarify the underlying characteristics potentially affecting that choice using the multicenter Stroke Acute Management with Urgent Risk‐factor Assessment and Improvement‐NVAF registry (ClinicalTrials.gov NCT01581502). Method The study included 1192 acute ischemic stroke/transient ischemic attack patients with nonvalvular atrial fibrillation (527 women, 77·7 ± 9·9 years old) between September 2011 and March 2014, during which three nonvitamin K antagonist oral anticoagulant oral anticoagulants were approved for clinical use. Oral anticoagulant choice at hospital discharge (median 23‐day stay) was assessed. Results Warfarin was chosen for 650 patients, dabigatran for 203, rivaroxaban for 238, and apixaban for 25. Over the three 10‐month observation periods, patients taking warfarin gradually decreased to 46·5% and those taking nonvitamin K antagonist oral anticoagulants increased to 48·0%. As compared with warfarin users, patients taking nonvitamin K antagonist oral anticoagulants included more men, were younger, more frequently had small infarcts, and had lower scores for poststroke CHADS 2, CHA 2 DS 2‐VASc, and HAS‐BLED, admission National Institutes of Health stroke scale, and discharge modified Rankin Scale. Nonvitamin K antagonist oral anticoagulants were started at a median of four‐days after stroke onset without early intracranial hemorrhage. Patients starting nonvitamin K antagonist oral anticoagulants earlier had smaller infarcts and lower scores for the admission National Institutes of Health stroke scale and the discharge modified Rankin Scale than those starting later. Choice of nonvitamin K antagonist oral anticoagulants was independently associated with 20‐day or shorter hospitalization (OR 2·46, 95% CI 1·87–3·24). Conclusions Warfarin use at acute hospital discharge was still common in the initial years after approval of nonvitamin K antagonist oral anticoagulants, although nonvitamin K antagonist oral anticoagulant users increased gradually. The index stroke was milder and ischemia‐risk indices were lower in nonvitamin K antagonist oral anticoagulant users than in warfarin users. Early initiation of nonvitamin K antagonist oral anticoagulants seemed safe. PMID:25581108

Long-term outcomes after stenting versus endarterectomy for treatment of symptomatic carotid stenosis: the International Carotid Stenting Study (ICSS) randomised trial

PubMed Central

Bonati, Leo H; Dobson, Joanna; Featherstone, Roland L; Ederle, Jörg; van der Worp, H Bart; de Borst, Gert J; Mali, Willem P Th M; Beard, Jonathan D; Cleveland, Trevor; Engelter, Stefan T; Lyrer, Philippe A; Ford, Gary A; Dorman, Paul J; Brown, Martin M

2015-01-01

Summary Background Stenting is an alternative to endarterectomy for treatment of carotid artery stenosis, but long-term efficacy is uncertain. We report long-term data from the randomised International Carotid Stenting Study comparison of these treatments. Methods Patients with symptomatic carotid stenosis were randomly assigned 1:1 to open treatment with stenting or endarterectomy at 50 centres worldwide. Randomisation was computer generated centrally and allocated by telephone call or fax. Major outcomes were assessed by an independent endpoint committee unaware of treatment assignment. The primary endpoint was fatal or disabling stroke in any territory after randomisation to the end of follow-up. Analysis was by intention to treat ([ITT] all patients) and per protocol from 31 days after treatment (all patients in whom assigned treatment was completed). Functional ability was rated with the modified Rankin scale. This study is registered, number ISRCTN25337470. Findings 1713 patients were assigned to stenting (n=855) or endarterectomy (n=858) and followed up for a median of 4·2 years (IQR 3·0–5·2, maximum 10·0). Three patients withdrew immediately and, therefore, the ITT population comprised 1710 patients. The number of fatal or disabling strokes (52 vs 49) and cumulative 5-year risk did not differ significantly between the stenting and endarterectomy groups (6·4% vs 6·5%; hazard ratio [HR] 1·06, 95% CI 0·72–1·57, p=0·77). Any stroke was more frequent in the stenting group than in the endarterectomy group (119 vs 72 events; ITT population, 5-year cumulative risk 15·2% vs 9·4%, HR 1·71, 95% CI 1·28–2·30, p<0·001; per-protocol population, 5-year cumulative risk 8·9% vs 5·8%, 1·53, 1·02–2·31, p=0·04), but were mainly non-disabling strokes. The distribution of modified Rankin scale scores at 1 year, 5 years, or final follow-up did not differ significantly between treatment groups. Interpretation Long-term functional outcome and risk of fatal or disabling stroke are similar for stenting and endarterectomy for symptomatic carotid stenosis. Funding Medical Research Council, Stroke Association, Sanofi-Synthélabo, European Union. PMID:25453443

Auckland Stroke Outcomes Study. Part 1: Gender, stroke types, ethnicity, and functional outcomes 5 years poststroke.

PubMed

Feigin, V L; Barker-Collo, S; Parag, V; Senior, H; Lawes, C M M; Ratnasabapathy, Y; Glen, E

2010-11-02

Studying long-term stroke outcomes including body functioning (neurologic and neuropsychological impairments) and activity limitations and participation is essential for long-term evidence-based rehabilitation and service planning, resource allocation, and improving health outcomes in stroke. However, reliable data to address these issues is lacking. This study (February 2007-December 2008) sourced its participants from the population-based incidence study conducted in Auckland in 2002-2003. Participants completed structured self-administered questionnaires, and a face-to-face interview including a battery of neuropsychological tests. Logistic regression analysis was used to analyze associations between and within functional outcomes and their potential predictors. Of 418 5-year stroke survivors, two-thirds had good functional outcome in terms of neurologic impairment and disability (defined as modified Rankin Score <3), 22.5% had cognitive impairment indicative of dementia, 20% had experienced a recurrent stroke, almost 15% were institutionalized, and 29.6% had symptoms suggesting depression. Highly significant correlations were found between and within various measurements of body functioning (especially neuropsychological impairments), activity, and participation. Age, dependency, and depression were independently associated with most outcomes analyzed. The strong associations between neuropsychological impairment and other functional outcomes and across various measurements of body functioning, activity, and participation justify utilizing a multidisciplinary approach to studying and managing long-term stroke outcomes. Observed gender and ethnic differences in some important stroke outcomes warrant further investigations.

ε-Aminocaproic acid in angiographically negative subarachnoid hemorrhage patients is safe: a retrospective review of 83 consecutive patients.

PubMed

Hui, Ferdinand K; Schuette, Albert J; Lieber, Michael; Spiotta, Alejandro M; Moskowitz, Shaye I; Barrow, Daniel L; Cawley, C Michael

2012-03-01

ε-Aminocaproic acid (EACA) has been used to reduce the rate of cerebral aneurysm rerupture before definitive treatment. In centers administering EACA to patients with a subarachnoid hemorrhage (SAH), patients eventually diagnosed with angiographically negative subarachnoid hemorrhage (ANSAH) may also initially receive EACA, perhaps placing them at increased risk for ischemic complications. To evaluate the effect of short-term EACA on outcomes and secondary measures in patients with ANSAH. We conducted a retrospective study of 454 consecutive SAH patients over a 2-year period under a current protocol for EACA use. Patients were excluded if a source for the SAH was discovered, yielding a total of 83 ANSAH patients. The patients were assigned to groups that did or did not receive EACA. The primary end points of the study were ischemic complications, pulmonary emboli, vasospasm, ventriculoperitoneal shunting rates, and outcomes. Statistical analysis yielded no significant difference between the 2 arms with respect to any of the end points: vasospasm (P = .65), deep vein thrombosis (P = .51), pulmonary embolism (P = 1.0), stroke (P = 1.0), myocardial infarction (P = 1.0), and ventriculoperitoneal shunt (P = .57). There was no statistically significant outcome difference using the modified Rankin Scale (P = .30). Short-term (<72 hour) application of EACA does not result in an increase in adverse events in patients with ANSAH.

Technology verification phase. Dynamic isotope power system. Final report

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

Halsey, D.G.

1982-03-10

The Phase I requirements of the Kilowatt Isotope Power System (KIPS) program were to make a detailed Flight System Conceptual Design (FSCD) for an isotope fueled organic Rankine cycle power system and to build and test a Ground Demonstration System (GDS) which simulated as closely as possible the operational characteristics of the FSCD. The activities and results of Phase II, the Technology Verification Phase, of the program are reported. The objectives of this phase were to increase system efficiency to 18.1% by component development, to demonstrate system reliability by a 5000 h endurance test and to update the flight systemmore » design. During Phase II, system performance was improved from 15.1% to 16.6%, an endurance test of 2000 h was performed while the flight design analysis was limited to a study of the General Purpose Heat Source, a study of the regenerator manufacturing technique and analysis of the hardness of the system to a laser threat. It was concluded from these tests that the GDS is basically prototypic of a flight design; all components necessary for satisfactory operation were demonstrated successfully at the system level; over 11,000 total h of operation without any component failure attested to the inherent reliability of this type of system; and some further development is required, specifically in the area of performance. (LCL)« less

Non-Ideal Compressible-Fluid Dynamics of Fast-Response Pressure Probes for Unsteady Flow Measurements in Turbomachinery

NASA Astrophysics Data System (ADS)

Gori, G.; Molesini, P.; Persico, G.; Guardone, A.

2017-03-01

The dynamic response of pressure probes for unsteady flow measurements in turbomachinery is investigated numerically for fluids operating in non-ideal thermodynamic conditions, which are relevant for e.g. Organic Rankine Cycles (ORC) and super-critical CO2 applications. The step response of a fast-response pressure probe is investigated numerically in order to assess the expected time response when operating in the non-ideal fluid regime. Numerical simulations are carried out exploiting the Non-Ideal Compressible Fluid-Dynamics (NICFD) solver embedded in the open-source fluid dynamics code SU2. The computational framework is assessed against available experimental data for air in dilute conditions. Then, polytropic ideal gas (PIG), i.e. constant specific heats, and Peng-Robinson Stryjek-Vera (PRSV) models are applied to simulate the flow field within the probe operating with siloxane fluid octamethyltrisiloxane (MDM). The step responses are found to depend mainly on the speed of sound of the working fluid, indicating that molecular complexity plays a major role in determining the promptness of the measurement devices. According to the PRSV model, non-ideal effects can increase the step response time with respect to the acoustic theory predictions. The fundamental derivative of gas-dynamic is confirmed to be the driving parameter for evaluating non-ideal thermodynamic effects related to the dynamic calibration of fast-response aerodynamic pressure probes.

Performance of deep geothermal energy systems

NASA Astrophysics Data System (ADS)

Manikonda, Nikhil

Geothermal energy is an important source of clean and renewable energy. This project deals with the study of deep geothermal power plants for the generation of electricity. The design involves the extraction of heat from the Earth and its conversion into electricity. This is performed by allowing fluid deep into the Earth where it gets heated due to the surrounding rock. The fluid gets vaporized and returns to the surface in a heat pipe. Finally, the energy of the fluid is converted into electricity using turbine or organic rankine cycle (ORC). The main feature of the system is the employment of side channels to increase the amount of thermal energy extracted. A finite difference computer model is developed to solve the heat transport equation. The numerical model was employed to evaluate the performance of the design. The major goal was to optimize the output power as a function of parameters such as thermal diffusivity of the rock, depth of the main well, number and length of lateral channels. The sustainable lifetime of the system for a target output power of 2 MW has been calculated for deep geothermal systems with drilling depths of 8000 and 10000 meters, and a financial analysis has been performed to evaluate the economic feasibility of the system for a practical range of geothermal parameters. Results show promising an outlook for deep geothermal systems for practical applications.

Decompressive Surgery for the Treatment of Malignant Infarction of the Middle Cerebral Artery (DESTINY): a randomized, controlled trial.

PubMed

Jüttler, Eric; Schwab, Stefan; Schmiedek, Peter; Unterberg, Andreas; Hennerici, Michael; Woitzik, Johannes; Witte, Steffen; Jenetzky, Ekkehart; Hacke, Werner

2007-09-01

Decompressive surgery (hemicraniectomy) for life-threatening massive cerebral infarction represents a controversial issue in neurocritical care medicine. We report here the 30-day mortality and 6- and 12-month functional outcomes from the DESTINY trial. DESTINY (ISRCTN01258591) is a prospective, multicenter, randomized, controlled, clinical trial based on a sequential design that used mortality after 30 days as the first end point. When this end point was reached, patient enrollment was interrupted as per protocol until recalculation of the projected sample size was performed on the basis of the 6-month outcome (primary end point=modified Rankin Scale score, dichotomized to 0 to 3 versus 4 to 6). All analyses were based on intention to treat. A statistically significant reduction in mortality was reached after 32 patients had been included: 15 of 17 (88%) patients randomized to hemicraniectomy versus 7 of 15 (47%) patients randomized to conservative therapy survived after 30 days (P=0.02). After 6 and 12 months, 47% of patients in the surgical arm versus 27% of patients in the conservative treatment arm had a modified Rankin Scale score of 0 to 3 (P=0.23). DESTINY showed that hemicraniectomy reduces mortality in large hemispheric stroke. With 32 patients included, the primary end point failed to demonstrate statistical superiority of hemicraniectomy, and the projected sample size was calculated to 188 patients. Despite this failure to meet the primary end point, the steering committee decided to terminate the trial in light of the results of the joint analysis of the 3 European hemicraniectomy trials.

Eleven years' experience with Intrathecal Baclofen - Complications, risk factors.

PubMed

Pucks-Faes, Elke; Hitzenberger, Gabriel; Matzak, Heinrich; Fava, Elena; Verrienti, Giulio; Laimer, Ilse; Fritz, Josef; Saltuari, Leopold

2018-05-01

Treatment with intrathecal baclofen (ITB) is commonly used in patients with severe spasticity. However, complications may occur after implantation of the ITB-device, albeit mainly procedure- and device-related problems. The aim of the study was to assess surgical- as well as catheter- and pump-related complications and define their risk factors. We retrospectively evaluated all patients with an implanted ITB-device who were treated at the Department of Neurology, Hochzirl Hospital, Zirl, Austria, between 2006 and 2016. Twenty-nine of 116 (25%) patients experienced 32 complications: 5 procedure- and 27 device-related (4 pump- and 23 catheter-associated) problems occurred. Risk factors for sustaining any complication were a spinal localization of lesion (odds ratio [OR] OR 2.71, p  = .021), other catheter types than an Ascenda ® catheter (OR 3.87, p  = .041), a lower modified Rankin Scale (median 4 vs. 5; OR 2.86, p  = .015) and a higher Barthel Index (median 53 vs. 0; OR 2.84, p  = .006). The median time from the last ITB-related surgery to the first complication was 18 (IQR 1-57) months. Overall, 47% complications occurred within the first year after any surgical procedure regarding the ITB-device, thereof 25% within the first month. Procedure- and device-related complications are frequent after implantation of an ITB-device with catheter-associated complications as the most frequently encountered problems. Patients with a spinal origin of spasticity, a lower modified Rankin Scale and a higher Barthel Index have a higher risk to sustain a complication.

The poor outcome of ischemic stroke in very old people: a cohort study of its determinants.

PubMed

Denti, Licia; Scoditti, Umberto; Tonelli, Claudio; Saccavini, Marsilio; Caminiti, Caterina; Valcavi, Rita; Benatti, Mario; Ceda, Gian Paolo

2010-01-01

To assess how much of the excess risk of poor outcome from stroke in people aged 80 and older aging per se explains, independent of other prognostic determinants. Cohort, observational. University hospital. One thousand five hundred fifty-five patients with first-ever ischemic stroke consecutively referred to an in-hospital Clinical Pathway program were studied. The relationship between age and 1-month outcome (death, disability (modified Rankin Scale 3-5), and poor outcome (modified Rankin Scale 3-6)) was assessed, with adjustment for several prognostic factors. Six hundred twelve patients aged 80 and older showed worse outcome after 1 month than those who were younger, in terms of mortality (19% vs 5%, hazard ratio (HR)=3.85, 95% confidence interval (CI)=2.8-5.4) and disability (51% vs 33%, odds ratio (OR)=3.16, 95% CI=2.5-4.0), although in multivariate models, the adjusted HR for mortality decreased to 1.47 (95% CI=1.0-2.16) and the ORs for disability and poor outcome decreased to 1.76 (95% CI=1.32-2.3.) and 1.83 (95% CI=137-2.43), respectively. Stroke severity, the occurrence of at least one medical complication, and premorbid disability explained most of the risk excess in the oldest-old. Stroke outcome is definitely worse in very old people, and most of the excess risk of death and disability is attributable to the higher occurrences of the most-severe clinical stroke syndromes and of medical complications in the acute phase. These represent potential targets for preventive and therapeutical strategies specifically for elderly people.

Concentrating Solar Power Gen3 Demonstration Roadmap

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

Mehos, Mark; Turchi, Craig; Vidal, Judith

Today's power-tower concentrating solar power (CSP) technology exists in large part as a result of Department of Energy (DOE) and utility industry funding of demonstration systems in the 1980s and 1990s. Today's most advanced towers are integrated with molten-salt thermal energy storage, delivering thermal energy at 565 degrees C for integration with conventional steam-Rankine cycles. The supercritical carbon dioxide power cycle has been identified as a likely successor to the steam-Rankine power cycle due to its potential for high efficiency when operating at elevated temperatures of 700 degrees C or greater. Over the course of the SunShot Initiative, DOE hasmore » supported a number of technology pathways that can operate efficiently at these temperatures and that hold promise to be reliable and cost effective. Three pathways - molten salt, particle, and gaseous - were selected for further investigation based on a two-day workshop held in August of 2016. The information contained in this roadmap identifies research and development challenges and lays out recommended research activities for each of the three pathways. DOE foresees that by successfully addressing the challenges identified in this roadmap, one or more technology pathways will be positioned for demonstration and subsequent commercialization within the next ten years. Based on current knowledge of the three power tower technologies, all three have the potential to achieve the SunShot goal of 6 cents/kilowatt-hour. Further development, modeling, and testing are now required to bring one or more of the technologies to a stage where integrated system tests and pilot demonstrations are feasible.« less

Endovascular Treatment of Ruptured Vertebrobasilar Dissecting Aneurysms Using Flow Diversion Embolization Devices: Single-Institution Experience.

PubMed

Guerrero, Waldo R; Ortega-Gutierrez, Santiago; Hayakawa, Minako; Derdeyn, Colin P; Rossen, James D; Hasan, David; Samaniego, Edgar A

2018-01-01

Treatment of ruptured posterior circulation dissecting aneurysms is technically challenging with potentially high morbidity and mortality. We sought to assess the safety and feasibility of using a flow-diversion device (FDD) and a specific acute antiplatelet aggregation protocol in the management of ruptured dissecting aneurysms. Subjects with ruptured dissecting aneurysms treated during a 3-year period were retrospectively identified from a prospective registry. Intraoperative complications, morbidity, and mortality were recorded. Tirofiban maintenance infusion without bolus was administered intravenously immediately after deployment of the FDD, and almost all patients were loaded with dual antiplatelet (aspirin and clopidogrel) post procedure. Clinical follow-up evaluation and modified Rankin Scale were assessed. Nine subjects with ruptured posterior circulation dissecting aneurysms were treated with an FDD: 5 vertebral artery, 2 basilar artery, and 2 posterior inferior cerebellar artery aneurysms. Average World Federation of Neurosurgical Societies score was 2 (range 1-5). Seven patients had external ventricular drain placed acutely for hydrocephalus. Eight patients received tirofiban infusion without bolus after FDD. No intraoperative complications occurred. Two subjects developed asymptomatic intraparenchymal hemorrhage found on surveillance noncontrast computed tomography. One subject suffered a major intraparenchymal hemorrhage and died a few days post intervention after additional anticoagulation was started for a left ventricular assist device. Follow-up modified Rankin Scale within 12 months was 0 in 3 subjects, 1 in 3 subjects, 2 in 1 subject, and 4 in 1. Treatment of dissecting posterior circulation aneurysms with FDDs is feasible and a potential alternative to deconstructive techniques. Copyright © 2017 Elsevier Inc. All rights reserved.

Antidepressant Use After Aneurysmal Subarachnoid Hemorrhage: A Population-Based Case-Control Study.

PubMed

Huttunen, Jukka; Lindgren, Antti; Kurki, Mitja I; Huttunen, Terhi; Frösen, Juhana; von Und Zu Fraunberg, Mikael; Koivisto, Timo; Kälviäinen, Reetta; Räikkönen, Katri; Viinamäki, Heimo; Jääskeläinen, Juha E; Immonen, Arto

2016-09-01

To elucidate the predictors of antidepressant use after subarachnoid hemorrhage from saccular intracranial aneurysm (sIA-SAH) in a population-based cohort with matched controls. The Kuopio sIA database includes all unruptured and ruptured sIA cases admitted to the Kuopio University Hospital from its defined catchment population in Eastern Finland, with 3 matched controls for each patient. The use of all prescribed medicines has been fused from the Finnish national registry of prescribed medicines. In the present study, 2 or more purchases of antidepressant medication indicated antidepressant use. The risk factors of the antidepressant use were analyzed in 940 patients alive 12 months after sIA-SAH, and the classification tree analysis was used to create a predicting model for antidepressant use after sIA-SAH. The 940 12-month survivors of sIA-SAH had significantly more antidepressant use (odds ratio, 2.6; 95% confidence interval, 2.2-3.1) than their 2676 matched controls (29% versus 14%). Classification tree analysis, based on independent risk factors, was used for the best prediction model of antidepressant use after sIA-SAH. Modified Rankin Scale until 12 months was the most potent predictor, followed by condition (Hunt and Hess Scale) and age on admission for sIA-SAH. The sIA-SAH survivors use significantly more often antidepressants, indicative of depression, than their matched population controls. Even with a seemingly good recovery (modified Rankin Scale score, 0) at 12 months after sIA-SAH, there is a significant risk of depression requiring antidepressant medication. © 2016 American Heart Association, Inc.

Sporadic Inclusion Body Myositis: MRI Findings and Correlation With Clinical and Functional Parameters.

PubMed

Guimaraes, Julio Brandao; Zanoteli, Edmar; Link, Thomas M; de Camargo, Leonardo V; Facchetti, Luca; Nardo, Lorenzo; Fernandes, Artur da Rocha Correa

2017-12-01

The purpose of this prospective study is to assess MRI findings in patients with sporadic inclusion body myositis (IBM) and correlate them with clinical and functional parameters. This study included 12 patients with biopsy-proven sporadic IBM. All patients underwent MRI of the bilateral upper and lower extremities. The images were scored for muscle atrophy, fatty infiltration, and edema pattern. Clinical data included onset and duration of disease. Muscle strength was measured using the Medical Research Council (MRC) scale, and functional status was assessed using the Modified Rankin Scale. Correlation between MRI and different clinical and functional parameters was calculated using the Spearman rank test and Pearson correlation. All patients showed MRI abnormalities, which were more severe within the lower limbs and the distal segments. The most prevalent MRI finding was fat infiltration. There was a statistically significant correlation between disease duration and number of muscles infiltrated by fat (r = 0.65; p = 0.04). The number of muscles with fat infiltration correlated with the sum of the scores of MRC (r = -0.60; p = 0.04) and with the Modified Rankin Scale (r = 0.48; p = 0.03). Our findings suggest that most patients with biopsy-proven sporadic IBM present with a typical pattern of muscle involvement at MRI, more extensively in the lower extremities. Moreover, MRI findings strongly correlated with clinical and functional parameters, because both the extent and severity of muscle involvement assessed by MRI and clinical and functional parameters are associated with the early onset of the disease and its duration.

Energy Conversion Alternatives Study (ECAS), Westinghouse phase 1. Volume 6: Closed-cycle gas turbine systems. [energy conversion efficiency in electric power plants

NASA Technical Reports Server (NTRS)

Amos, D. J.; Fentress, W. K.; Stahl, W. F.

1976-01-01

Both recuperated and bottomed closed cycle gas turbine systems in electric power plants were studied. All systems used a pressurizing gas turbine coupled with a pressurized furnace to heat the helium for the closed cycle gas turbine. Steam and organic vapors are used as Rankine bottoming fluids. Although plant efficiencies of over 40% are calculated for some plants, the resultant cost of electricity was found to be 8.75 mills/MJ (31.5 mills/kWh). These plants do not appear practical for coal or oil fired plants.

Phase 1 of the First Small Power System Experiment (engineering Experiment No. 1). Volume 1: Executive Summary. [development and testing of a solar thermal power plant

NASA Technical Reports Server (NTRS)

Holl, R. J.

1979-01-01

The development of a modular solar thermal power system for application in the 1 to 10 MWe range is presented. The system is used in remote utility applications, small communities, rural areas, and for industrial uses. Investigations are performed on the energy storage requirements and type of energy storage, concentrator design and field optimization, energy transport, and power conversion subsystems. The system utilizes a Rankine cycle, an axial flow steam turbine for power conversion, and heat transfer sodium for collector fluid.

The Physical Tourist Physics in Glasgow: A Heritage Tour

NASA Astrophysics Data System (ADS)

Johnston, Sean F.

2006-12-01

I trace the history of the physical and applied sciences, and particularly physics, in Glasgow. Among the notable individuals I discuss are Joseph Black (1728 1799), James Watt (1736 1819), William John Macquorn Rankine (1820 1872), William Thomson, Lord Kelvin (1824 1907), John Kerr (1824 1907), Frederick Soddy (1877 1956), John Logie Baird (1888 1946), and Ian Donald (1910 1987), as well as physics-related businesses.The locations, centering on the city center and University of Glasgow, include sites both recognizable today and transformed from past usage, as well as museums and archives related to the history and interpretation of physics.

Shock conditions and shock wave structures in a steady flow in a dissipative fluid

NASA Technical Reports Server (NTRS)

Germain, P.; Guiraud, J. P.

1983-01-01

More precisely, calling xi the reciprocal of the Reynolds number based on the shock wave curvature radius, the xi terms of the first order are systematically taken into account. The most important result is a system of formulas giving a correction of order xi for the various RANKINE-HUGONIOT conditions. The suggested formulas may for instance have to be used instead of the conventional ones to evaluate the loss of the total pressure across the detached shock wave which is found at the nose of a very small probe in supersonic flow.

Preliminary design package for solar heating and cooling systems

NASA Technical Reports Server (NTRS)

1978-01-01

Summarized preliminary design information on activities associated with the development, delivery and support of solar heating and cooling systems is given. These systems are for single family dwellings and commercial applications. The heating/cooling system use a reversible vapor compression heat pump that is driven in the cooling mode by a Rankine power loop, and in the heating mode by a variable speed electric motor. The heating/cooling systems differ from the heating-only systems in the arrangement of the heat pump subsystem and the addition of a cooling tower to provide the heat sink for cooling mode operation.

Power Supply for a Manned International Asteroid Mission

NASA Technical Reports Server (NTRS)

Weingartner, Stefan; Nahra, Henry K.; Kohout, Lisa L.; Larin, Max

1991-01-01

A feasibility study considering the exploitation of a near Earth asteroid was performed. The power requirements and proposed power systems for the crew vehicle, cargo vehicles, mining and processing equipment are described. A photovoltaic power system was selected to meet the 52.1 kWe and the 3.9 kWe power requirements of the crew and cargo vehicles, respectively. A nuclear power plant using a thermodynamic Rankine cycle with a total mass of 62.1 tons was chosen to provide the 7.225 MWe and the 5.5 MWth required for the mining and processing activities at the asteroid.

Prognosis of untreated strokes due to anterior circulation proximal intracranial arterial occlusions detected by use of computed tomography angiography.

PubMed

Lima, Fabricio O; Furie, Karen L; Silva, Gisele S; Lev, Michael H; Camargo, Erica C S; Singhal, Aneesh B; Harris, Gordon J; Halpern, Elkan F; Koroshetz, Walter J; Smith, Wade S; Nogueira, Raul G

2014-02-01

Limited data exist regarding the natural history of proximal intracranial arterial occlusions. OBJECTIVE To investigate the outcomes of patients who had an acute ischemic stroke attributed to an anterior circulation proximal intracranial arterial occlusion. A prospective cohort study at 2 university-based hospitals from 2003 to 2005 in which nonenhanced computed tomography scans and computed tomography angiograms were obtained at admission of all adult patients suspected of having an ischemic stroke in the first 24 hours of symptom onset. Anterior circulation proximal intracranial arterial occlusion. Frequency of good outcome (defined as a modified Rankin Scale score of ≤ 2) and mortality at 6 months. A total of 126 patients with a unilateral complete occlusion of the intracranial internal carotid artery (ICA; 26 patients: median National Institutes of Health Stroke Scale [NIHSS] score, 11 [interquartile range, 5-17]), of the M1 segment of the middle cerebral artery (MCA; 52 patients: median NIHSS score, 13 [interquartile range, 6-16]), or of the M2 segment of the MCA (48 patients: median NIHSS score, 7 [interquartile range, 4-15]) were included. Of these 3 groups of patients, 10 (38.5%), 20 (38.5%), and 26 (54.2%) with ICA, MCA-M1, and MCA-M2 occlusions, respectively, achieved a modified Rankin Scale score of 2 or less, and 6 (23.1%), 12 (23.1%), and 10 (20.8%) were dead at 6 months. Worse outcomes were seen in patients with a baseline NIHSS score of 10 or higher, with a modified Rankin Scale score of 2 or less achieved in only 7.1% (1 of 14), 23.5% (8 of 34), and 22.7% (5 of 22) of patients and mortality rates of 35.7% (5 of 14), 32.4% (11 of 34), and 40.9% (9 of 22) among patients with ICA, MCA-M1, and MCA-M2 occlusions, respectively. Age (odds ratio, 0.94 [95% CI, 0.91-0.98]), NIHSS score (odds ratio, 0.73 [95% CI, 0.64-0.83]), and strength of leptomeningeal collaterals (odds ratio, 2.37 [95% CI, 1.08-5.20]) were independently associated with outcome, whereas the level of proximal intracranial arterial occlusion (ICA vs MCA-M1 vs MCA-M2) was not. The natural history of proximal intracranial arterial occlusion is variable, with poor outcomes overall. Stroke severity and collateral flow appear to be more important than the level of proximal intracranial arterial occlusion in determining outcomes. Our results provide useful data for proper patient selection and sample size calculations in the design of new clinical trials aimed at recanalization therapies.

Analysis of a rotating spool expander for Organic Rankine Cycle applications

NASA Astrophysics Data System (ADS)

Krishna, Abhinav

Increasing interest in recovering or utilizing low-grade heat for power generation has prompted a search for ways in which the power conversion process may be enhanced. Amongst the conversion systems, the Organic Rankine Cycle (ORC) has generated an enormous amount of interest amongst researchers and system designers. Nevertheless, component level technologies need to be developed and match the range of potential applications. In particular, technical challenges associated with scaling expansion machines (turbines) from utility scale to commercial scale have prevented widespread adoption of the technology. In this regard, this work focuses on a novel rotating spool expansion machine at the heart of an Organic Rankine Cycle. A comprehensive, deterministic simulation model of the rotating spool expander is developed. The comprehensive model includes a detailed geometry model of the spool expander and the suction valve mechanism. Sub-models for mass flow, leakage, heat transfer and friction within the expander are also developed. Apart from providing the ability to characterize the expander in a particular system, the model provides a valuable tool to study the impact of various design variables on the performance of the machine. The investigative approach also involved an experimental program to assess the performance of a working prototype. In general, the experimental data showed that the expander performance was sub-par, largely due to the mismatch of prevailing operating conditions and the expander design criteria. Operating challenges during the shakedown tests and subsequent sub-optimal design changes also detracted from performance. Nevertheless, the results of the experimental program were sufficient for a proof-of-concept assessment of the expander and for model validation over a wide range of operating conditions. The results of the validated model reveal several interesting details concerning the expander design and performance. For example, the match between the design expansion ratio and the system imposed pressure ratio has a large influence on the performance of the expander. Further exploration shows that from an operating perspective, under-expansion is preferable to over-expansion. The model is also able to provide insight on the dominant leakage paths in the expander and points to the fact that this is the primary loss mechanism in the current expander. Similar insights are obtained from assessing the sensitivity of various other design variables on expander performance. Based on the understanding provided by the sensitivity analysis, exercising the validated model showed that expander efficiencies on the order of 75% are imminently possible in an improved design. Therefore, with sufficient future development, adoption of the spool expander in ORC systems that span a 50 kW -- 200 kW range is broadly feasible.

Resuscitation Outcomes Consortium (ROC) PRIMED Cardiac Arrest Trial Methods Part 2: Rationale and Methodology for “Analyze Later” Protocol

PubMed Central

Stiell, Ian G.; Callaway, Clif; Davis, Dan; Terndrup, Tom; Powell, Judy; Cook, Andrea; Kudenchuk, Peter J.; Daya, Mohamud; Kerber, Richard; Idris, Ahamed; Morrison, Laurie J.; Aufderheide, Tom

2008-01-01

Objective The primary objective of the trial is to compare survival to hospital discharge with Modified Rankin Score (MRS) ≤3 between a strategy that prioritizes a specified period of CPR before rhythm analysis (Analyze Later) versus a strategy of minimal CPR followed by early rhythm analysis (Analyze Early) in patients with out-of-hospital cardiac arrest. Methods   Design Cluster randomized trial with cluster units defined by geographic region, or monitor/defibrillator machine. Population Adults treated by Emergency Medical Service (EMS) providers for non-traumatic out-of-hospital cardiac arrest not witnessed by EMS. Setting EMS systems participating in the Resuscitation Outcomes Consortium and agreeing to cluster randomization to the Analyze Later versus Analyze Early intervention in a crossover fashion. Sample Size Based on a two-sided significance level of 0.05, a maximum of 13,239 evaluable patients will allow statistical power of 0.996 to detect a hypothesized improvement in the probability of survival to discharge with MRS ≤ 3 rate from 5.41% after Analyze Early to 7.45% after Analyze Later (2.04% absolute increase in primary outcome). Conclusion If this trial demonstrates a significant improvement in survival with a strategy of Analyze Later, it is estimated that 4,000 premature deaths from cardiac arrest would be averted annually in North America alone. PMID:18487004

Impact of Neutral Boundary-Layer Turbulence on Wind-Turbine Wakes: A Numerical Modelling Study

NASA Astrophysics Data System (ADS)

Englberger, Antonia; Dörnbrack, Andreas

2017-03-01

The wake characteristics of a wind turbine in a turbulent boundary layer under neutral stratification are investigated systematically by means of large-eddy simulations. A methodology to maintain the turbulence of the background flow for simulations with open horizontal boundaries, without the necessity of the permanent import of turbulence data from a precursor simulation, was implemented in the geophysical flow solver EULAG. These requirements are fulfilled by applying the spectral energy distribution of a neutral boundary layer in the wind-turbine simulations. A detailed analysis of the wake response towards different turbulence levels of the background flow results in a more rapid recovery of the wake for a higher level of turbulence. A modified version of the Rankine-Froude actuator disc model and the blade element momentum method are tested as wind-turbine parametrizations resulting in a strong dependence of the near-wake wind field on the parametrization, whereas the far-wake flow is fairly insensitive to it. The wake characteristics are influenced by the two considered airfoils in the blade element momentum method up to a streamwise distance of 14 D ( D = rotor diameter). In addition, the swirl induced by the rotation has an impact on the velocity field of the wind turbine even in the far wake. Further, a wake response study reveals a considerable effect of different subgrid-scale closure models on the streamwise turbulent intensity.

The interaction of turbulence with parallel and perpendicular shocks

NASA Astrophysics Data System (ADS)

Adhikari, L.; Zank, G. P.; Hunana, P.; Hu, Q.

2016-11-01

Interplanetary shocks exist in most astrophysical flows, and modify the properties of the background flow. We apply the Zank et al 2012 six coupled turbulence transport model equations to study the interaction of turbulence with parallel and perpendicular shock waves in the solar wind. We model the 1D structure of a stationary perpendicular or parallel shock wave using a hyperbolic tangent function and the Rankine-Hugoniot conditions. A reduced turbulence transport model (the 4-equation model) is applied to parallel and perpendicular shock waves, and solved using a 4th- order Runge Kutta method. We compare the model results with ACE spacecraft observations. We identify one quasi-parallel and one quasi-perpendicular event in the ACE spacecraft data sets, and compute various turbulent observed values such as the fluctuating magnetic and kinetic energy, the energy in forward and backward propagating modes, the total turbulent energy in the upstream and downstream of the shock. We also calculate the error associated with each turbulent observed value, and fit the observed values by a least square method and use a Fourier series fitting function. We find that the theoretical results are in reasonable agreement with observations. The energy in turbulent fluctuations is enhanced and the correlation length is approximately constant at the shock. Similarly, the normalized cross helicity increases across a perpendicular shock, and decreases across a parallel shock.

Mediterranean Diet in patients with acute ischemic stroke: Relationships between Mediterranean Diet score, diagnostic subtype, and stroke severity index.

PubMed

Tuttolomondo, Antonino; Casuccio, Alessandra; Buttà, Carmelo; Pecoraro, Rosaria; Di Raimondo, Domenico; Della Corte, Vittoriano; Arnao, Valentina; Clemente, Giuseppe; Maida, Carlo; Simonetta, Irene; Miceli, Giuseppe; Lucifora, Benedetto; Cirrincione, Anna; Di Bona, Danilo; Corpora, Francesca; Maugeri, Rosario; Iacopino, Domenico Gerardo; Pinto, Antonio

2015-11-01

Adherence to a Mediterranean Diet appears to reduce the risk of cardiovascular disease, cancer, Alzheimer's disease, and Parkinson's disease, as well as the risk of death due to cardiovascular disease. No study has addressed the association between diagnostic subtype of stroke and its severity and adherence to a Mediterranean Diet in subjects with acute ischemic stroke. To evaluate the association between Mediterranean Diet adherence, TOAST subtype, and stroke severity by means of a retrospective study. The type of acute ischemic stroke was classified according to the TOAST criteria. All patients admitted to our ward with acute ischemic stroke completed a 137-item validated food-frequency questionnaire adapted to the Sicilian population. A scale indicating the degree of adherence to the traditional Mediterranean Diet was used (Me-Di score: range 0-9). 198 subjects with acute ischemic stroke and 100 control subjects without stroke. Stroke subjects had a lower mean Mediterranean Diet score compared to 100 controls without stroke. We observed a significant positive correlation between Me-Di score and SSS score, whereas we observed a negative relationship between Me-Di score and NIHSS and Rankin scores. Subjects with atherosclerotic (LAAS) stroke subtype had a lower mean Me-Di score compared to subjects with other subtypes. Multinomial logistic regression analysis in a simple model showed a negative relationship between MeDi score and LAAS subtype vs. lacunar subtype (and LAAS vs. cardio-embolic subtype). Patients with lower adherence to a Mediterranean Diet are more likely to have an atherosclerotic (LAAS) stroke, a worse clinical presentation of ischemic stroke at admission and a higher Rankin score at discharge. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

Anxiety After Stroke

PubMed Central

Whiteley, William N.; Dennis, Martin S.; Mead, Gillian E.; Carson, Alan J.

2018-01-01

Background and Purpose— Anxiety after stroke is common and disabling. Stroke trialists have treated anxiety as a homogenous condition, and intervention studies have followed suit, neglecting the different treatment approaches for phobic and generalized anxiety. Using diagnostic psychiatric interviews, we aimed to report the frequency of phobic and generalized anxiety, phobic avoidance, predictors of anxiety, and patient outcomes at 3 months poststroke/transient ischemic attack. Methods— We followed prospectively a cohort of new diagnosis of stroke/transient ischemic attack at 3 months with a telephone semistructured psychiatric interview, Fear Questionnaire, modified Rankin Scale, EuroQol-5D5L, and Work and Social Adjustment Scale. Results— Anxiety disorder was common (any anxiety disorder, 38 of 175 [22%]). Phobic disorder was the predominant anxiety subtype: phobic disorder only, 18 of 175 (10%); phobic and generalized anxiety disorder, 13 of 175 (7%); and generalized anxiety disorder only, 7 of 175 (4%). Participants with anxiety disorder reported higher level of phobic avoidance across all situations on the Fear Questionnaire. Younger age (per decade increase in odds ratio, 0.64; 95% confidence interval, 0.45–0.91) and having previous anxiety/depression (odds ratio, 4.38; 95% confidence interval, 1.94–9.89) were predictors for anxiety poststroke/transient ischemic attack. Participants with anxiety disorder were more dependent (modified Rankin Scale score 3–5, [anxiety] 55% versus [no anxiety] 29%; P<0.0005), had poorer quality of life on EQ-5D5L, and restricted participation (Work and Social Adjustment Scale: median, interquartile range, [anxiety] 19.5, 10–27 versus [no anxiety] 0, 0–5; P<0.001). Conclusions— Anxiety after stroke/transient ischemic attack is predominantly phobic and is associated with poorer patient outcomes. Trials of anxiety intervention in stroke should consider the different treatment approaches needed for phobic and generalized anxiety. PMID:29437982

Anxiety After Stroke: The Importance of Subtyping.

PubMed

Chun, Ho-Yan Yvonne; Whiteley, William N; Dennis, Martin S; Mead, Gillian E; Carson, Alan J

2018-03-01

Anxiety after stroke is common and disabling. Stroke trialists have treated anxiety as a homogenous condition, and intervention studies have followed suit, neglecting the different treatment approaches for phobic and generalized anxiety. Using diagnostic psychiatric interviews, we aimed to report the frequency of phobic and generalized anxiety, phobic avoidance, predictors of anxiety, and patient outcomes at 3 months poststroke/transient ischemic attack. We followed prospectively a cohort of new diagnosis of stroke/transient ischemic attack at 3 months with a telephone semistructured psychiatric interview, Fear Questionnaire, modified Rankin Scale, EuroQol-5D5L, and Work and Social Adjustment Scale. Anxiety disorder was common (any anxiety disorder, 38 of 175 [22%]). Phobic disorder was the predominant anxiety subtype: phobic disorder only, 18 of 175 (10%); phobic and generalized anxiety disorder, 13 of 175 (7%); and generalized anxiety disorder only, 7 of 175 (4%). Participants with anxiety disorder reported higher level of phobic avoidance across all situations on the Fear Questionnaire. Younger age (per decade increase in odds ratio, 0.64; 95% confidence interval, 0.45-0.91) and having previous anxiety/depression (odds ratio, 4.38; 95% confidence interval, 1.94-9.89) were predictors for anxiety poststroke/transient ischemic attack. Participants with anxiety disorder were more dependent (modified Rankin Scale score 3-5, [anxiety] 55% versus [no anxiety] 29%; P <0.0005), had poorer quality of life on EQ-5D5L, and restricted participation (Work and Social Adjustment Scale: median, interquartile range, [anxiety] 19.5, 10-27 versus [no anxiety] 0, 0-5; P <0.001). Anxiety after stroke/transient ischemic attack is predominantly phobic and is associated with poorer patient outcomes. Trials of anxiety intervention in stroke should consider the different treatment approaches needed for phobic and generalized anxiety. © 2018 The Authors.

Feasibility of Multiple Burr Hole With Erythropoietin in Acute Moyamoya Patients.

PubMed

Hong, Ji Man; Lee, Seong-Joon; Lee, Jin Soo; Choi, Mun Hee; Lee, Sung Eun; Choi, Jin Wook; Lim, Yong Cheol

2018-05-01

In patients with acute symptomatic moyamoya (<2 weeks), the feasibility of a combination therapy of multiple burr hole procedure under local anesthesia and intravenous erythropoietin pretreatment was assessed. We also identified the factors associated with transdural revascularization. In this prospective single-arm study, perfusion-impaired patients presenting with transient ischemic attack or acute cerebral infarction were assessed. Combination therapy was performed to patients lacking transdural collaterals. Primary outcomes were evaluated clinically with modified Rankin Scale scores and radiologically with revascularization success (transhemispheric, trans-burr hole, and sufficient revascularizations [filling ≥33% of ipsilateral supratentorium]) at 6 months. Treatment-related adverse events were analyzed in 3 phases: pre burr hole, post burr hole, and after-discharge as secondary outcome. Factors associated with sufficient revascularization were investigated. Fifty hemispheres from 37 patients were included. Compared with discharge, modified Rankin Scale score at 6 months significantly improved (2.0 [0.0-5.0] versus 1.0 [0.0-4.0]; P <0.001). Majority had successful revascularization: trans-burr hole arteriogenesis (89.5%), transhemispheric arteriogenesis (98.0%), and sufficient revascularization (52.0%). There was no significant pre burr hole or post burr hole complication. Two (5.4%) transient ischemic attack and 1 (2.7%) cerebral infarction occurred after discharge. Presentation with acute infarction (odds ratio, 4.8; 95% confidence interval, 1.1-21.4), ipsilateral basal moyamoya vessels (odds ratio, 13.9; 95% confidence interval, 1.3-144.2), and delayed mean transit time (odds ratio, 3.9; 95% confidence interval, 1.3-12.2) predicted sufficient revascularization. Combination therapy allows safe and effective revascularization in moyamoya patients with acute ischemic presentation. URL: https://www.clinicaltrials.gov. Unique identifier: NCT03162588. © 2018 American Heart Association, Inc.

A retrospective study on the efficacy and safety of intraveinous immunoglobulin (Tegeline®) in patients with chronic inflammatory demyelinating polyneuropathy.

PubMed

Robert, Florence; Edan, Gilles; Nicolas, Guillaume; Pouget, Jean; Vial, Christophe; Antoine, Jean-Christophe; Puget, Sophie

2015-01-01

To assess the efficacy and safety of intraveinous immunoglobulin (IV Ig) in patients with chronic inflammatory demyelinating polyneuropathy (CIDP) at 4, 7 and 12months. A national multicenter retrospective study was conducted by LFB Biotehcnologies in patients with CIDP who had received at least one cycle of a 5% polyvalent IV Ig, Tegeline(®), from LFB biomédicaments between 1995 and 2004. The primary endpoint was the efficacy of IV Ig at 4 months, which was defined as the responder rate based on the modified Rankin scale. Several secondary endpoints were assessed: safety and efficacy (i.e., responders according to the investigators' overall assessment of the patients' status) at 4, 7 and 12 months. The analysis was performed at 7 months only (due to missing data for 12 months and few patients). A total of 26 patients were included who had received between 1 and 6 cycles of IV Ig (mean 3±2) with a median follow-up of 9.9 months. The responder rate at 4 months based on the modified Rankin scale was 52% (95% CI 0.313-0.722), whereas the responder rate with placebo reported in the literature (meta-analysis including results from van Schaik and an ICE study) is 18% (P<0.001). Responder patients at 4 months were still responders at 7 months. The overall safety of IV Ig was good, with adverse events of mild to moderate severity, which resolved without sequelae and were expected adverse events of IV Ig. This retrospective study confirmed both the efficacy of IV Ig at 4 months in the treatment of chronic inflammatory demyelinating polyneuropathy and the favorable safety profile of the product. Copyright © 2015 Elsevier Masson SAS. All rights reserved.

ORACLE Stroke Study: Opinion Regarding Acceptable Outcome Following Decompressive Hemicraniectomy for Ischemic Stroke.

PubMed

Honeybul, Stephen; Ho, Kwok M; Blacker, David W

2016-08-01

There continues to be considerable interest in the use of decompressive hemicraniectomy in the management of malignant cerebral artery infarction; however, concerns remain about long-term outcome. To assess opinion on consent and acceptable outcome among a wide range of healthcare workers. Seven hundred seventy-three healthcare workers at the 2 major public neurosurgical centers in Western Australia participated. Participants were asked to record their opinion on consent and acceptable outcome based on the modified Rankin Score (mRS). The evidence for clinical efficacy of the procedure was presented, and participants were then asked to reconsider their initial responses. Of the 773 participants included in the study, 407 (52.7%) initially felt that they would provide consent for a decompressive craniectomy as a lifesaving procedure, but only a minority of them considered an mRS score of 4 or 5 an acceptable outcome (for mRS score ≤4, n = 67, 8.7%; for mRS score = 4, n = 57, 7.4%). After the introduction of the concept of the disability paradox and the evidence for the clinical efficacy of decompressive craniectomy, more participants were unwilling to accept decompressive craniectomy (18.1% vs 37.8%), but at the same time, more were willing to accept an mRS score ≤4 as an acceptable outcome (for mRS score ≤4, n = 92, 11.9%; for mRS score = 4, n = 79, 10.2%). Most participants felt survival with dependency to be unacceptable. However, many would be willing to provide consent for surgery in the hopes that they may survive with some degree of independence. DESTINY, Decompressive Surgery for the Treatment of Malignant Infarction of the Middle Cerebral ArterymRS, modified Rankin Scale.

Restarting antiplatelet therapy after spontaneous intracerebral hemorrhage: Functional outcomes.

PubMed

Chen, Ching-Jen; Ding, Dale; Buell, Thomas J; Testai, Fernando D; Koch, Sebastian; Woo, Daniel; Worrall, Bradford B

2018-05-30

To compare the functional outcomes and health-related quality of life metrics of restarting vs not restarting antiplatelet therapy (APT) in patients presenting with intracerebral hemorrhage (ICH) in the ERICH (Ethnic/Racial Variations of Intracerebral Hemorrhage) study. Adult patients aged 18 years and older who were on APT before ICH and were alive at hospital discharge were included. Patients were dichotomized based on whether or not APT was restarted after hospital discharge. The primary outcome was a modified Rankin Scale score of 0-2 at 90 days. Secondary outcomes were excellent outcome (modified Rankin Scale score 0-1), mortality, Barthel Index, and health status (EuroQol-5 dimensions [EQ-5D] and EQ-5D visual analog scale scores) at 90 days. The APT and no APT cohorts comprised 127 and 732 patients, respectively. Restarting APT was associated with lower rates of good functional outcome (36.5% vs 40.8%; p = 0.021) and lower Barthel Index scores at 90 days ( p = 0.041). The 2 cohorts were then matched in a 1:1 ratio, and the matched cohorts each comprised 107 patients. No difference in primary outcome was observed between restarting vs not restarting APT (35.5% vs 43.9%; p = 0.105). There were also no differences between the secondary outcomes of the 2 cohorts. Restarting APT in patients with ICH of mild to moderate severity after acute hospitalization is not associated with worse functional outcomes or health-related quality of life at 90 days. In patients with significant cardiovascular risk factors who experience an ICH, restarting APT remains the decision of the treating practitioner. © 2018 American Academy of Neurology.

Measuring the impact of multiple sclerosis on psychosocial functioning: the development of a new self-efficacy scale.

PubMed

Airlie, J; Baker, G A; Smith, S J; Young, C A

2001-06-01

To develop a scale to measure self-efficacy in neurologically impaired patients with multiple sclerosis and to assess the scale's psychometric properties. Cross-sectional questionnaire study in a clinical setting, the retest questionnaire returned by mail after completion at home. Regional multiple sclerosis (MS) outpatient clinic or the Clinical Trials Unit (CTU) at a large neuroscience centre in the UK. One hundred persons with MS attending the Walton Centre for Neurology and Neurosurgery and Clatterbridge Hospital, Wirral, as outpatients. Cognitively impaired patients were excluded at an initial clinic assessment. Patients were asked to provide demographic data and complete the self-efficacy scale along with the following validated scales: Hospital Anxiety and Depression Scale, Rosenberg Self-Esteem Scale, Impact, Stigma and Mastery and Rankin Scales. The Rankin Scale and Barthel Index were also assessed by the physician. A new 11-item self-efficacy scale was constructed consisting of two domains of control and personal agency. The validity of the scale was confirmed using Cronbach's alpha analysis of internal consistency (alpha = 0.81). The test-retest reliability of the scale over two weeks was acceptable with an intraclass correlation coefficient of 0.79. Construct validity was investigated using Pearson's product moment correlation coefficient resulting in significant correlations with depression (r= -0.52) anxiety (r =-0.50) and mastery (r= 0.73). Multiple regression analysis demonstrated that these factors accounted for 70% of the variance of scores on the self-efficacy scale, with scores on mastery, anxiety and perceived disability being independently significant. Assessment of the psychometric properties of this new self-efficacy scale suggest that it possesses good validity and reliability in patients with multiple sclerosis.

Randomized Controlled Trial of Early Versus Delayed Statin Therapy in Patients With Acute Ischemic Stroke: ASSORT Trial (Administration of Statin on Acute Ischemic Stroke Patient).

PubMed

Yoshimura, Shinichi; Uchida, Kazutaka; Daimon, Takashi; Takashima, Ryuzo; Kimura, Kazuhiro; Morimoto, Takeshi

2017-11-01

Several studies suggested that statins during hospitalization were associated with better disability outcomes in patients with acute ischemic stroke, but only 1 small randomized trial is available. We conducted a multicenter, open-label, randomized controlled trial in patients with acute ischemic strokes in 11 hospitals in Japan. Patients with acute ischemic stroke and dyslipidemia randomly received statins within 24 hours after admission in the early group or on the seventh day in the delayed group, in a 1:1 ratio. Statins were administered for 12 weeks. The primary outcome was patient disability assessed by modified Rankin Scale at 90 days. A total of 257 patients were randomized and analyzed (early 131, delayed 126). At 90 days, modified Rankin Scale score distribution did not differ between groups ( P =0.68), and the adjusted common odds ratio of the early statin group was 0.84 (95% confidence interval, 0.53-1.3; P =0.46) compared with the delayed statin group. There were 3 deaths at 90 days (2 in the early group, 1 in the delayed group) because of malignancy. Ischemic stroke recurred in 9 patients (6.9%) in the early group and 5 patients (4.0%) in the delayed group. The safety profile was similar between groups. Our randomized trial involving patients with acute ischemic stroke and dyslipidemia did not show any superiority of early statin therapy within 24 hours of admission compared with delayed statin therapy 7 days after admission to alleviate the degree of disability at 90 days after onset. URL: http://www.clinicaltrials.gov. Unique identifier: NCT02549846. © 2017 American Heart Association, Inc.

Admission Glucose and Effect of Intra-Arterial Treatment in Patients With Acute Ischemic Stroke.

PubMed

Osei, Elizabeth; den Hertog, Heleen M; Berkhemer, Olvert A; Fransen, Puck S S; Roos, Yvo B W E M; Beumer, Debbie; van Oostenbrugge, Robert J; Schonewille, Wouter J; Boiten, Jelis; Zandbergen, Adrienne A M; Koudstaal, Peter J; Dippel, Diederik W J

2017-05-01

Hyperglycemia on admission is common after ischemic stroke. It is associated with unfavorable outcome after treatment with intravenous thrombolysis and after intra-arterial treatment. Whether hyperglycemia influences the effect of reperfusion treatment is unknown. We assessed whether increased admission serum glucose modifies the effect of intra-arterial treatment in patients with acute ischemic stroke. We used data from the MR CLEAN (Multicenter Randomized Clinical Trial of Endovascular Treatment for Acute Ischemic Stroke in the Netherlands). Hyperglycemia was defined as admission serum glucose >7.8 mmol/L. The primary outcome measure was the adjusted common odds ratio for a shift in the direction of a better outcome on the modified Rankin Scale at 90 days, estimated with ordinal logistic regression. Secondary outcome variable was symptomatic intracranial hemorrhage. We assessed treatment effect modification of hyperglycemia and admission serum glucose levels with multiplicative interaction factors and adjusted for prognostic variables. Four hundred eighty-seven patients were included. Mean admission serum glucose was 7.2 mmol/L (SD, 2.2). Fifty-seven of 226 patients (25%) randomized to intra-arterial treatment were hyperglycemic compared with 61 of 261 patients (23%) in the control group. The interaction of either hyperglycemia or admission serum glucose levels and treatment effect on modified Rankin Scale scores was not significant ( P =0.67 and P =0.87, respectively). The same applied for occurrence of symptomatic hemorrhage ( P =0.39 for hyperglycemia, P =0.39 for admission serum glucose). We found no evidence for effect modification of intra-arterial treatment by admission serum glucose in patients with acute ischemic stroke. URL: www.isrctn.com. Unique identifier: ISRCTN10888758. © 2017 American Heart Association, Inc.

A cross-sectional study of quality of life in incident stroke survivors in rural northern Tanzania.

PubMed

Howitt, Suzanne C; Jones, Matthew P; Jusabani, Ahmed; Gray, William K; Aris, Eric; Mugusi, Ferdinand; Swai, Mark; Walker, Richard W

2011-08-01

The aim of this study was to evaluate changes to, and predictors of, quality of life (QOL) in a community-based cohort of stroke survivors from an earlier stroke incidence study in rural northern Tanzania. Patients were assessed 1-5 years after their incident stroke. The study cohort was compared with an age- and sex-matched control group from the same rural district within a cross-sectional design. Patients and controls were asked a series of questions relating to their QOL [World Health Organization quality of life, abbreviated version (WHOQOL-BREF)], levels of anxiety and depression [hospital anxiety and depression (HAD) scale], cognitive function [community screening instrument for dementia (CSI-D) screening tool], socioeconomic status and demographic characteristics (e.g. age, sex, education and abode). Patients were further assessed for functional outcome and disability (Barthel index, modified Rankin scale), post-stroke care and psychosocial functioning. Patients (n = 58) were found to have significantly lower QOL than controls (n = 58) in all six domains of the WHOQOL-BREF. Gender, socioeconomic status, cognitive function and time elapsed since stroke were not associated with QOL. Older patients and those with more impaired motor function and disability (Barthel index, modified Rankin score) had significantly poorer physical health-related QOL. Greater anxiety and depression, reduced muscle power and less involvement in social events were significantly correlated with lower physical and psychological health-related QOL. To our knowledge, this is the first long-term study of QOL in survivors of incident stroke in Sub-Saharan Africa (SSA). Poorer QOL was associated with greater levels of physical disability, anxiety and depression and reduced social interaction. Demographic factors appear to be much less significant. Modifying these QOL predictors could be important in planning effective post-stroke care within a stretched healthcare system.

A Stent-Retrieving into an Aspiration Catheter with Proximal Balloon (ASAP) Technique: A Technique of Mechanical Thrombectomy.

PubMed

Goto, Shunsaku; Ohshima, Tomotaka; Ishikawa, Kojiro; Yamamoto, Taiki; Shimato, Shinji; Nishizawa, Toshihisa; Kato, Kyozo

2018-01-01

The best technique for the first attempt at mechanical thrombectomy for acute ischemic stroke is a still matter of debate. In this study, we evaluate the efficacy of a stent-retrieving into an aspiration catheter with proximal balloon (ASAP) technique that uses a series of thrombus extraction by withdrawing the stent retriever into the aspiration catheter and continuous aspiration from the aspiration catheter at the first attempt. We performed a retrospective analysis of 42 consecutive patients with acute ischemic stroke caused by occlusions in the anterior circulation who were treated with the ASAP technique at our institution. Preoperative patient characteristic, including age, thrombus location, Alberta Stroke Program Early CT Score, National Institutions of Health Stroke Scale, and time from onset to puncture; postoperative Thrombolysis in Cerebral Infarction score; modified Rankin Scale score after 3 months; time from puncture to recanalization; the number of passes to achieve recanalization; and procedural complications, including intracranial hemorrhage, embolization to new territory, and distal embolization, were assessed. A Thrombolysis in Cerebral Infarction score of 2B or 3 was achieved in 40/42 patients (95.2%). Average time from puncture to the final recanalization was 21.5 minutes. Recanalization was achieved in a single attempt in 31 patients (77.5%). Embolization to new territory was observed in only 2 patients (4.8%); no patient developed distal embolization or intracranial hemorrhage including asymptomatic subarachnoid hemorrhage. Thirty-two patients (76.2%) achieved modified Rankin Scale scores of 0-2 at 3 months postoperatively. Our ASAP technique showed fast recanalization, minimal complications, and good clinical outcomes in this case series. Copyright © 2017 Elsevier Inc. All rights reserved.

Predictors of Good Outcome After Endovascular Therapy for Vertebrobasilar Occlusion Stroke.

PubMed

Bouslama, Mehdi; Haussen, Diogo C; Aghaebrahim, Amin; Grossberg, Jonathan A; Walker, Gregory; Rangaraju, Srikant; Horev, Anat; Frankel, Michael R; Nogueira, Raul G; Jovin, Tudor G; Jadhav, Ashutosh P

2017-12-01

Endovascular therapy is increasingly used in acute ischemic stroke treatment and is now considered the gold standard approach for selected patient populations. Prior studies have demonstrated that eventual patient outcomes depend on both patient-specific factors and procedural considerations. However, these factors remain unclear for acute basilar artery occlusion stroke. We sought to determine prognostic factors of good outcome in acute posterior circulation large vessel occlusion strokes treated with endovascular therapy. We reviewed our prospectively collected endovascular databases at 2 US tertiary care academic institutions for patients with acute posterior circulation strokes from September 2005 to September 2015 who had 3-month modified Rankin Scale documented. Baseline characteristics, procedural data, and outcomes were evaluated. A good outcome was defined as a 90-day modified Rankin Scale score of 0 to 2. The association between clinical and procedural parameters and functional outcome was assessed. A total of 214 patients qualified for the study. Smoking status, creatinine levels, baseline National Institutes of Health Stroke Scale score, anesthesia modality (conscious sedation versus general anesthesia), procedural length, and reperfusion status were significantly associated with good outcomes in the univariate analysis. Multivariate logistic regression indicated that only smoking (odds ratio=2.61; 95% confidence interval, 1.23-5.56; P =0.013), low baseline National Institutes of Health Stroke Scale score (odds ratio=1.09; 95% confidence interval, 1.04-1.13; P <0.0001), and successful reperfusion status (odds ratio=10.80; 95% confidence interval, 1.36-85.96; P =0.025) were associated with good outcome. In our retrospective case series, only smoking, low baseline National Institutes of Health Stroke Scale score, and successful reperfusion status were associated with good outcome in patients with posterior circulation stroke treated with endovascular therapy. © 2017 American Heart Association, Inc.

Brainstem leukoaraiosis independently predicts poor outcome after ischemic stroke.

PubMed

Giralt-Steinhauer, E; Medrano, S; Soriano-Tárraga, C; Mola-Caminal, M; Rasal, R; Cuadrado-Godia, E; Rodríguez-Campello, A; Ois, A; Capellades, J; Jimenez-Conde, J; Roquer, J

2018-04-16

Increased supratentorial white matter hyperintensities volume (S-WMHV) has been reported to be a predictor of worse outcome in patients with acute ischemic stroke (AIS). However, few studies have focused on less common locations, such as brainstem white matter hyperintensities (B-WMH), and their relationship to S-WMHV. This study aimed to examine whether B-WMH affect clinical outcome after AIS or transient ischemic attack (TIA). Based on magnetic resonance imaging evidence, B-WMH were evaluated in 313 prospectively identified patients with AIS/TIA and registered as absent or present. Standardized S-WMHV was quantified using a validated volumetric image analysis and natural log-transformed (Log_S-WMHV). Poor outcome was defined as a modified Rankin Scale score of 3-6 at 3 months after the index event. Brainstem white matter hyperintensities were detected in 57 (18.2%) patients. In unadjusted analyses for outcome, the presence of B-WMH was associated with worse outcome, compared with patients without B-WMH (P = 0.034). In multivariate analysis controlling for age, atrial fibrillation, stroke severity, reperfusion therapies and Log_S-WMHV, only B-WMH [odds ratio (OR), 2.46; P = 0.021] and stroke severity (OR, 1.23; P < 0.001) remained independently associated with unfavourable 90-day modified Rankin Scale score. Patients with B-WMH were older (OR, 1.06; P < 0.001) and tended to have more hyperlipidaemia (OR, 2.21; P = 0.023) and peripheral arterial disease (OR, 2.57; P = 0.031). Brainstem white matter hyperintensities are an independent predictor of poor outcome after AIS/TIA and this relationship persists after adjustment for important prognostic factors. Our results also show that leukoaraiosis in this location identifies patients with a specific risk factor profile, suggesting differences in the underlying pathogenesis. © 2018 EAN.

Transcranial laser therapy in acute stroke treatment: results of neurothera effectiveness and safety trial 3, a phase III clinical end point device trial.

PubMed

Hacke, Werner; Schellinger, Peter D; Albers, Gregory W; Bornstein, Natan M; Dahlof, Bjorn L; Fulton, Rachael; Kasner, Scott E; Shuaib, Ashfaq; Richieri, Steven P; Dilly, Stephen G; Zivin, Justin; Lees, Kennedy R

2014-11-01

On the basis of phase II trials, we considered that transcranial laser therapy could have neuroprotective effects in patients with acute ischemic stroke. We studied transcranial laser therapy in a double-blind, sham-controlled randomized clinical trial intended to enroll 1000 patients with acute ischemic stroke treated ≤24 hours after stroke onset and who did not undergo thrombolytic therapy. The primary efficacy measure was the 90-day functional outcome as assessed by the modified Rankin Scale, with hierarchical Bayesian analysis incorporating relevant previous data. Interim analyses were planned after 300 and 600 patients included. The study was terminated on recommendation by the Data Monitoring Committee after a futility analysis of 566 completed patients found no difference in the primary end point (transcranial laser therapy 140/282 [49.6%] versus sham 140/284 [49.3%] for good functional outcome; modified Rankin Scale, 0-2). The results remained stable after inclusion of all 630 randomized patients (adjusted odds ratio, 1.024; 95% confidence interval, 0.705-1.488). Once the results of the interim futility analysis became available, all study support was immediately withdrawn by the capital firms behind PhotoThera, and the company was dissolved. Proper termination of the trial was difficult but was finally achieved through special efforts by former employees of PhotoThera, the CRO Parexel and members of the steering and the safety committees. We conclude that transcranial laser therapy does not have a measurable neuroprotective effect in patients with acute ischemic stroke when applied within 24 hours after stroke onset. http://www.clinicaltrials.gov. Unique identifier: NCT01120301. © 2014 American Heart Association, Inc.

Efficiency of the Penumbra 5MAX ACE Reperfusion Catheter in Acute Ischemic Stroke Patients.

PubMed

Suzuki, Kentaro; Aoki, Junya; Sakamoto, Yuki; Kanamaru, Takuya; Abe, Arata; Suda, Satoshi; Okubo, Seiji; Kimura, Kazumi

2016-12-01

This study was performed to investigate whether the Penumbra 5MAX ACE is superior to other Penumbra systems. We performed a retrospective, single center analysis of patients with acute ischemic stroke with occlusion of the internal carotid artery or middle cerebral artery (M1 segment) who underwent endovascular therapy using a Penumbra system. The reperfusion success rate, puncture-to-revascularization time, and number of passes were assessed. Multivariate regression analysis was conducted to evaluate independent factors related to revascularization within 60 minutes. Successful revascularization was defined by a thrombolysis in cerebral infarction score ≥2b. The Penumbra 5MAX ACE was used in 24 of the 40 patients (60%). Although the revascularization success rate was similar between patient groups (P = .229), the number of passes was significantly lower (1.5 ± .8 versus 2.6 ± 1.3, P = .006) and the puncture-to-revascularization time was shorter (50 ± 26 minutes versus 116 ± 69 minutes, P = .002) in patients treated with the Penumbra 5MAX ACE. The Penumbra 5MAX ACE was identified as an independent factor for early revascularization (odds ratio, 5.80; P = .041). Among patients with a premorbid modified Rankin Scale score of 0-1, a modified Rankin Scale score of 0-2 at 3 months was observed in 15 of the 19 patients (79%) treated with the Penumbra 5MAX ACE and in 8 of the 16 (50%) who were not (P = .072). Acute revascularization therapy using the Penumbra 5MAX ACE can achieve rapid successful recanalization and tend to improve clinical outcomes. Copyright © 2016 National Stroke Association. Published by Elsevier Inc. All rights reserved.

Good outcome rate of 35% in IV-tPA-treated patients with computed tomography angiography confirmed severe anterior circulation occlusive stroke.

PubMed

González, R Gilberto; Furie, Karen L; Goldmacher, Gregory V; Smith, Wade S; Kamalian, Shervin; Payabvash, Seyedmehdi; Harris, Gordon J; Halpern, Elkan F; Koroshetz, Walter J; Camargo, Erica C S; Dillon, William P; Lev, Michael H

2013-11-01

To determine the effect of intravenous tissue plasminogen activator (IV-tPA) on outcomes in patients with severe major anterior circulation ischemic stroke. Prospectively, 649 patients with acute stroke had admission National Institutes of Health stroke scale (NIHSS) scores, noncontrast computed tomography (CT), CT angiography (CTA), and 6-month outcome assessed using modified Rankin scale. IV-tPA treatment decisions were made before CTA, at the time of noncontrast CT scanning, as per routine clinical protocol. Severe symptoms were defined as NIHSS>10. Poor outcome was defined as modified Rankin scale >2. Major occlusions were identified on CTA. Univariate and multivariate stepwise-forward logistic regression analyses of the full cohort were performed. Of 649 patients, 188 (29%) patients presented with NIHSS>10, and 64 out of 188 (34%) patients received IV-tPA. Admission NIHSS, large artery occlusion, and IV-tPA all independently predicted good outcomes; however, a significant interaction existed between IV-tPA and occlusion (P<0.001). Of the patients who presented with NIHSS>10 with anterior circulation occlusion, twice the percentage had good outcomes if they received IV-tPA (17 out of 49 patients, 35%) than if they did not (13 out of 77 patients, 17%; P=0.031). The number needed to treat was 7 (95% confidence interval, 3-60). IV-tPA treatment resulted in significantly better outcomes in patients with severely symptomatic stroke with major anterior circulation occlusions. The 35% good outcome rate was similar to rates found in endovascular therapy trials. Vascular imaging may help in patient selection and stratification for trials of IV-thrombolytic and endovascular therapies.