WorldWideScience

Sample records for rankine reheat reciprocator

  1. Reciprocating Expander for an Exhaust Heat Recovery Rankine Cycle for a Passenger Car Application

    Directory of Open Access Journals (Sweden)

    Osoko Shonda

    2012-06-01

    Full Text Available Nowadays, on average, two thirds of the fuel energy consumed by an engine is wasted through the exhaust gases and the cooling liquid. The recovery of this energy would enable a substantial reduction in fuel consumption. One solution is to integrate a heat recovery system based on a steam Rankine cycle. The key component in such a system is the expander, which has a strong impact on the system’s performance. A survey of different expander technologies leads us to select the reciprocating expander as the most promising one for an automotive application. This paper therefore proposes a steady-state semi-empirical model of the expander device developed under the Engineering Equation Solver (EES environment. The ambient and mechanical losses as well as internal leakage were taken into account by the model. By exploiting the expander manufacturer’s data, all the parameters of the expander model were identified. The model computes the mass flow rate, the power output delivered and the exhaust enthalpy of the steam. The maximum deviation between predictions and measurement data is 4.7%. A performance study of the expander is carried out and shows that the isentropic efficiency is quite high and increases with the expander rotary speed. The mechanical efficiency depends on mechanical losses which are quite high, approximately 90%. The volumetric efficiency was also evaluated.

  2. Design and development of an automotive organic Rankine-cycle powerplant with a reciprocating expander. Final report. Volume II. Detailed discussion

    Energy Technology Data Exchange (ETDEWEB)

    1977-09-01

    Work performed for the design and development of an organic Rankine-cycle engine for automobile propulsion is reported. An automotive power plant using an organic Rankine-cycle system with a reciprocating expander has been designed, built, and tested on an engine dynamometer in a preprototype configuration. The system is designed to provide performance approximately equivalent to that of a 351-CID internal combustion engine in the reference car, a 1972 Ford Galaxie 500. A description of the preprototype system, major components, and results from component and system testing are presented. The fuel economy based on steady-state measurements is estimated to be 10.2 mpg over the federal driving cycle with a maximum of 16 mpg at 30 mph. Projections of steady-state emission measurements show compliance with the 1970 Clean Air Act standards for 1978 vehicle emissions. The levels for unburned hydrocarbons, carbon monoxide, and oxides of nitrogen were 41 percent, 6 percent, and 69 percent of the standards, respectively. At the conclusion of the preprototype phase of the program, a prototype design effort was initiated to upgrade and improve the performance of the preprototype system. The reference vehicle for this prototype design is a compact car in the weight class of a 1974 Ford Pinto. The results of this design study, including performance projections, are also presented.

  3. Observing inflationary reheating.

    Science.gov (United States)

    Martin, Jérôme; Ringeval, Christophe; Vennin, Vincent

    2015-02-27

    Reheating is the epoch which connects inflation to the subsequent hot big-bang phase. Conceptually very important, this era is, however, observationally poorly known. We show that the current Planck satellite measurements of the cosmic microwave background (CMB) anisotropies constrain the kinematic properties of the reheating era for most of the inflationary models. This result is obtained by deriving the marginalized posterior distributions of the reheating parameter for about 200 models of slow-roll inflation. Weighted by the statistical evidence of each model to explain the data, we show that the Planck 2013 measurements induce an average reduction of the posterior-to-prior volume by 40%. Making some additional assumptions on reheating, such as specifying a mean equation of state parameter, or focusing the analysis on peculiar scenarios, can enhance or reduce this constraint. Our study also indicates that the Bayesian evidence of a model can substantially be affected by the reheating properties. The precision of the current CMB data is therefore such that estimating the observational performance of a model now requires incorporating information about its reheating history.

  4. Reheating-era leptogenesis

    Directory of Open Access Journals (Sweden)

    Yuta Hamada

    2016-12-01

    Full Text Available We propose a novel leptogenesis scenario at the reheating era. Our setup is minimal in the sense that, in addition to the standard model Lagrangian, we only consider an inflaton and higher dimensional operators. The lepton number asymmetry is produced not by the decay of a heavy particle, but by the scattering between the standard model particles. After the decay of an inflaton, the model is described within the standard model with higher dimensional operators. The Sakharov's three conditions are satisfied by the following way. The violation of the lepton number is realized by the dimension-5 operator. The complex phase comes from the dimension-6 four lepton operator. The universe is out of equilibrium before the reheating is completed. It is found that the successful baryogenesis is realized for the wide range of parameters, the inflaton mass and reheating temperature, depending on the cutoff scale. Since we only rely on the effective Lagrangian, our scenario can be applicable to all mechanisms to generate neutrino Majorana masses.

  5. Reheating-era leptogenesis

    Energy Technology Data Exchange (ETDEWEB)

    Hamada, Yuta, E-mail: hamada@gauge.scphys.kyoto-u.ac.jp; Kawana, Kiyoharu

    2016-12-10

    We propose a novel leptogenesis scenario at the reheating era. Our setup is minimal in the sense that, in addition to the standard model Lagrangian, we only consider an inflaton and higher dimensional operators. The lepton number asymmetry is produced not by the decay of a heavy particle, but by the scattering between the standard model particles. After the decay of an inflaton, the model is described within the standard model with higher dimensional operators. The Sakharov's three conditions are satisfied by the following way. The violation of the lepton number is realized by the dimension-5 operator. The complex phase comes from the dimension-6 four lepton operator. The universe is out of equilibrium before the reheating is completed. It is found that the successful baryogenesis is realized for the wide range of parameters, the inflaton mass and reheating temperature, depending on the cutoff scale. Since we only rely on the effective Lagrangian, our scenario can be applicable to all mechanisms to generate neutrino Majorana masses.

  6. A unified approach to reheat in gas and steam turbine cycles

    Energy Technology Data Exchange (ETDEWEB)

    Lewins, J. [University of Cambridge (United Kingdom). Magdalene College

    2005-06-15

    A model of fluid behaviour is proposed for both air and steam in Joule, Brayton, and Rankine cycles by assuming that enthalpy is a function of temperature only. This enables reheat to be treated in a unified manner for both gas and steam turbines. Theorems for maximum power and maximum thermal efficiency are presented, with extensions to inter-cooling in gas turbines and afterburners in turbo-jet craft. (author)

  7. Reheating for closed string inflation

    Energy Technology Data Exchange (ETDEWEB)

    Cicoli, Michele [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany); Mazumdar, Anupam [Lancaster Univ. (United Kingdom). Physics Dept.; Copenhagen Univ. (Denmark). Niels Bohr Institute

    2010-05-15

    We point out some of the outstanding challenges for embedding inflationary cosmology within string theory studying the process of reheating for models where the inflaton is a closed string mode parameterising the size of an internal cycle of the compactification manifold. A realistic model of inflation must explain the tiny perturbations in the cosmic microwave background radiation and also how to excite the ordinary matter degrees of freedom after inflation, required for the success of Big Bang Nucleosynthesis. We study these issues focusing on two promising inflationary models embedded in LARGE volume type IIB flux compactifications. We show that phenomenological requirements and consistency of the effective field theory treatment imply the presence at low energies of a hidden sector together with a visible sector, where the Minimal Supersymmetric Standard Model fields are residing. A detailed calculation of the inflaton coupling to the fields of the hidden sector, visible sector, and moduli sector, reveals that the inflaton fails to excite primarily the visible sector fields, instead hidden sector fields are excited copiously after the end of inflation. This sets severe constraints on hidden sector model building where the most promising scenario emerges as a pure N=1 SYM theory, forbidding the kinematical decay of the inflaton to the hidden sector. In this case it is possible to reheat the Universe with the visible degrees of freedom even though in some cases we discover a new tension between TeV scale SUSY and reheating on top of the well-known tension between TeV scale SUSY and inflation. (orig.)

  8. Reheating of the Universe as holographic thermalization

    Energy Technology Data Exchange (ETDEWEB)

    Kawai, Shinsuke, E-mail: shinsuke.kawai@gmail.com [Department of Physics, Sungkyunkwan University, Suwon 16419 (Korea, Republic of); Nakayama, Yu [California Institute of Technology, 452-48, Pasadena, CA 91125 (United States); Kavli Institute for the Physics and Mathematics of the Universe (WPI), Todai Institutes for Advanced Study, Kashiwa, Chiba 277-8583 (Japan)

    2016-08-10

    Assuming gauge/gravity correspondence we study reheating of the Universe using its holographic dual. Inflaton decay and thermalisation of the decay products correspond to collapse of a spherical shell and formation of a blackhole in the dual anti-de Sitter (AdS) spacetime. The reheating temperature is computed as the Hawking temperature of the developed blackhole probed by a dynamical boundary, and is determined by the inflaton energy density and the AdS radius, with corrections from the dynamics of the shell collapse. For given initial energy density of the inflaton field the holographic model typically gives lower reheating temperature than the instant reheating scenario, while it is shown to be safely within phenomenological bounds.

  9. Reheating of the Universe as holographic thermalization

    Directory of Open Access Journals (Sweden)

    Shinsuke Kawai

    2016-08-01

    Full Text Available Assuming gauge/gravity correspondence we study reheating of the Universe using its holographic dual. Inflaton decay and thermalisation of the decay products correspond to collapse of a spherical shell and formation of a blackhole in the dual anti-de Sitter (AdS spacetime. The reheating temperature is computed as the Hawking temperature of the developed blackhole probed by a dynamical boundary, and is determined by the inflaton energy density and the AdS radius, with corrections from the dynamics of the shell collapse. For given initial energy density of the inflaton field the holographic model typically gives lower reheating temperature than the instant reheating scenario, while it is shown to be safely within phenomenological bounds.

  10. Production of massive particles during reheating

    CERN Document Server

    Chung, D J H; Riotto, Antonio; Chung, Daniel J. H.; Kolb, Edward W.; Riotto, Antonio

    1999-01-01

    What is commonly called the reheat temperature, $T_{RH}$, is not the maximum temperature obtained after inflation. The maximum temperature is, in fact, much larger than $T_{RH}$. As an application of this we consider the production of massive stable dark-matter particles of mass $M_X$ during reheating, and show that their abundance is suppressed as a power of $T_{RH}/M_X$ rather than times the reheat temperature may be produced in interesting abundance. In addition to dark matter, our analysis is relevant for baryogenesis if the baryon asymmetry is produced by the baryon (or lepton) number violating decays of superheavy bosons, and also for relic ultra-high energy cosmic rays if decays of superheavy particles are responsible for the highest energy cosmic rays.

  11. Non-perturbative reheating and Nnaturalness

    Science.gov (United States)

    Hardy, Edward

    2017-11-01

    We study models in which reheating happens only through non-perturbative processes. The energy transferred can be exponentially suppressed unless the inflaton is coupled to a particle with a parametrically small mass. Additionally, in some models a light scalar with a negative mass squared parameter leads to much more efficient reheating than one with a positive mass squared of the same magnitude. If a theory contains many sectors similar to the Standard Model coupled to the inflaton via their Higgses, such dynamics can realise the Nnaturalness solution to the hierarchy problem. A sector containing a light Higgs with a non-zero vacuum expectation value is dominantly reheated and there is little energy transferred to the other sectors, consistent with cosmological constraints. The inflaton must decouple from other particles and have a flat potential at large field values, in which case the visible sector UV cutoff can be raised to 10 TeV in a simple model.

  12. Heat Pipe Precools and Reheats Dehumidified Air

    Science.gov (United States)

    Koning, R. C.; Boggs, W. H.; Barnett, U. R.; Dinh, K.

    1986-01-01

    Precooling and reheating by heat pipe reduces operating costs of air-conditioning. Warm air returned from air-conditioned space and cooled air supplied are precooled and reheated, respectively, by each other through a heat pipe. Heat-pipe technology brought to bear on problem of conserving airconditioning energy in hot, humid environments. Any increase in the cost of equipment due to installation of heat-pipe heat exchangers expected to be recovered in energy savings during service period of 2 years or less.

  13. Constrained superfields from inflation to reheating

    Directory of Open Access Journals (Sweden)

    Ioannis Dalianis

    2017-10-01

    Full Text Available We construct effective supergravity theories from customized constrained superfields which provide a setup consistent both for the description of inflation and the subsequent reheating processes. These theories contain the minimum degrees of freedom in the bosonic sector required for single-field inflation.

  14. No-reheat air-conditioning

    Science.gov (United States)

    Obler, H. D.

    1980-01-01

    Air conditioning system, for environmentally controlled areas containing sensitive equipment, regulates temperature and humidity without wasteful and costly reheating. System blends outside air with return air as dictated by various sensors to ensure required humidity in cooled spaces (such as computer room).

  15. Quantifying the reheating temperature of the universe

    Directory of Open Access Journals (Sweden)

    Anupam Mazumdar

    2014-09-01

    Full Text Available The aim of this paper is to determine an exact definition of the reheat temperature for a generic perturbative decay of the inflaton. In order to estimate the reheat temperature, there are two important conditions one needs to satisfy: (a the decay products of the inflaton must dominate the energy density of the universe, i.e. the universe becomes completely radiation dominated, and (b the decay products of the inflaton have attained local thermodynamical equilibrium. For some choices of parameters, the latter is a more stringent condition, such that the decay products may thermalise much after the beginning of radiation–domination. Consequently, we have obtained that the reheat temperature can be much lower than the standard-lore estimation. In this paper we describe under what conditions our universe could have efficient or inefficient thermalisation, and quantify the reheat temperature for both the scenarios. This result has an immediate impact on many applications which rely on the thermal history of the universe, in particular gravitino abundance.

  16. Rankine-cycle solar-cooling systems

    Science.gov (United States)

    Weathers, H. M.

    1979-01-01

    Report reviews progress made by three contractors to Marshall Space Flight Center and Department of Energy in developing Rankine-cycle machines for solar cooling and testing of commercially available equipment involved.

  17. Organic Rankine Cycles. Old wine in new bottles; Organic Rankine Cycles. Oude wijn in nieuwe zakken

    Energy Technology Data Exchange (ETDEWEB)

    Den Hartog, T.L.B. [Cumae, Arnhem (Netherlands)

    2007-05-15

    An overview is given of the renewed interest for the Organic Rankine Cycle technology and new developments with regard to this power generating technology. [Dutch] Een overzicht wordt gegeven van de hernieuwde belangstelling voor de Organic Rankine Cycle (ORC) technologie en nieuwe ontwikkeling m.b.t. deze vorm van elektriciteitopwekking.

  18. Constrains on Kähler moduli inflation from reheating

    Science.gov (United States)

    Bhattacharya, Sukannya; Dutta, Koushik; Maharana, Anshuman

    2017-10-01

    We present predictions of the Kähler moduli inflation model for the spectral tilt by parametrizing the reheating epoch by an effective equation-of-state parameter and the number of e-foldings of reheating; and taking into account the post-inflationary history of the model. This model has an epoch in which the energy density of the universe is dominated by cold moduli particles. We compare our results with data from the Planck mission and find that exotic reheating (with effective equation of state wre greater than 1 /3 ) or dark radiation is required to match the observations. For canonical reheating case with wre=0 , we deduce log10(Tre/103 GeV )≃1190 (ns-0.956 ). We also analyze our results in the context of observations being planned for the future and their projected sensitivities.

  19. Inflation and Reheating in Spontaneously Generated Gravity

    CERN Document Server

    Cerioni, A; Tronconi, A; Venturi, G

    2010-01-01

    Inflation is studied in the context of induced gravity (IG) $\\gamma \\sigma^2 R$, where $R$ is the Ricci scalar, $\\sigma$ a scalar field and $\\gamma$ a dimensionless constant, and diverse symmetry-breaking potentials $V(\\sigma)$ are considered. In particular we compared the predictions for Landau-Ginzburg (LG) and Coleman-Weinberg (CW) type potentials and their possible generalizations with the most recent data. We find that large field inflation generally leads to fewer constraints on the parameters and the shape of the potential whereas small field inflation is more problematic and, if viable, implies more constraints, in particular on the parameter $\\gamma$. We also examined the reheating phase and obtained an accurate analytical solution for the dynamics of inflaton and the Hubble parameter by using a multiple scale analysis (MSA). The solutions were then used to study the average expansion of the Universe, the average equation of state for the scalar field and both the perturbative and resonant decays of ...

  20. Electromagnetic Reciprocity.

    Energy Technology Data Exchange (ETDEWEB)

    Aldridge, David F.

    2014-11-01

    A reciprocity theorem is an explicit mathematical relationship between two different wavefields that can exist within the same space - time configuration. Reciprocity theorems provi de the theoretical underpinning for mod ern full waveform inversion solutions, and also suggest practical strategies for speed ing up large - scale numerical modeling of geophysical datasets . In the present work, several previously - developed electromagnetic r eciprocity theorems are generalized to accommodate a broader range of medi um, source , and receiver types. Reciprocity relations enabling the interchange of various types of point sources and point receivers within a three - dimensional electromagnetic model are derived. Two numerical modeling algorithms in current use are successfully tested for adherence to reciprocity. Finally, the reciprocity theorem forms the point of departure for a lengthy derivation of electromagnetic Frechet derivatives. These mathe matical objects quantify the sensitivity of geophysical electromagnetic data to variatio ns in medium parameters, and thus constitute indispensable tools for solution of the full waveform inverse problem. ACKNOWLEDGEMENTS Sandia National Labor atories is a multi - program laboratory managed and operated by Sandia Corporation, a wholly owned subsidiary of Lockheed Martin Corporation, for the US Department of Energy's National Nuclear Security Administration under contract DE - AC04 - 94AL85000. Signif icant portions of the work reported herein were conducted under a Cooperative Research and Development Agreement (CRADA) between Sandia National Laboratories (SNL) and CARBO Ceramics Incorporated. The author acknowledges Mr. Chad Cannan and Mr. Terry Pa lisch of CARBO Ceramics, and Ms. Amy Halloran, manager of SNL's Geophysics and Atmospheric Sciences Department, for their interest in and encouragement of this work. Special thanks are due to Dr . Lewis C. Bartel ( recently retired from Sandia National Labo ratories

  1. Device and Container for Reheating and Sterilization

    Science.gov (United States)

    Sastry, Sudhir K.; Heskitt, Brian F.; Jun, Soojin; Marcy, Joseph E.; Mahna, Ritesh

    2012-01-01

    Long-duration space missions require the development of improved foods and novel packages that do not represent a significant disposal issue. In addition, it would also be desirable if rapid heating technologies could be used on Earth as well, to improve food quality during a sterilization process. For this purpose, a package equipped with electrodes was developed that will enable rapid reheating of contents via ohmic heating to serving temperature during space vehicle transit. Further, the package is designed with a resealing feature, which enables the package, once used, to contain and sterilize waste, including human waste for storage prior to jettison during a long-duration mission. Ohmic heating is a technology that has been investigated on and off for over a century. Literature indicates that foods processed by ohmic heating are of superior quality to their conventionally processed counterparts. This is due to the speed and uniformity of ohmic heating, which minimizes exposure of sensitive materials to high temperatures. In principle, the material may be heated rapidly to sterilization conditions, cooled rapidly, and stored. The ohmic heating device herein is incorporated within a package. While this by itself is not novel, a reusable feature also was developed with the intent that waste may be stored and re-sterilized within the packages. These would then serve a useful function after their use in food processing and storage. The enclosure should be designed to minimize mass (and for NASA's purposes, Equivalent System Mass, or ESM), while enabling the sterilization function. It should also be electrically insulating. For this reason, Ultem high-strength, machinable electrical insulator was used.

  2. Cascaded organic rankine cycles for waste heat utilization

    Science.gov (United States)

    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.

  3. Medium capacity reheat steam turbines; Chuyoryo sainetsu joki turbine

    Energy Technology Data Exchange (ETDEWEB)

    Asano, S.; Takahashi, Y.; Moriyama, T. [Fuji Electric Co. Ltd., Tokyo (Japan)

    2000-12-12

    Worldwide movements for serious environmental problems and free power marketing, in addition to increasing reheat plants for the gas turbine combined cycle, have increased market needs for medium capacity reheat steam turbines. Fuji Electric has newly developed a high-performance machine to meet the market needs. The machine realizes compactness through optimum design, including the basic turbine construction, valve arrangement and security system, as well as high efficiency by using the new type profile, and is capable of good operation and manipulation using recent digital control technology. (author)

  4. Toluene stability Space Station Rankine power system

    Science.gov (United States)

    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.

  5. Organic rankine cycle waste heat applications

    Science.gov (United States)

    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.

  6. Technology Development Program for an Advanced Potassium Rankine Power Conversion System Compatible with Several Space Reactor Designs

    Energy Technology Data Exchange (ETDEWEB)

    Yoder, G.L.

    2005-10-03

    This report documents the work performed during the first phase of the National Aeronautics and Space Administration (NASA), National Research Announcement (NRA) Technology Development Program for an Advanced Potassium Rankine Power Conversion System Compatible with Several Space Reactor Designs. The document includes an optimization of both 100-kW{sub e} and 250-kW{sub e} (at the propulsion unit) Rankine cycle power conversion systems. In order to perform the mass optimization of these systems, several parametric evaluations of different design options were investigated. These options included feed and reheat, vapor superheat levels entering the turbine, three different material types, and multiple heat rejection system designs. The overall masses of these Nb-1%Zr systems are approximately 3100 kg and 6300 kg for the 100- kW{sub e} and 250-kW{sub e} systems, respectively, each with two totally redundant power conversion units, including the mass of the single reactor and shield. Initial conceptual designs for each of the components were developed in order to estimate component masses. In addition, an overall system concept was presented that was designed to fit within the launch envelope of a heavy lift vehicle. A technology development plan is presented in the report that describes the major efforts that are required to reach a technology readiness level of 6. A 10-year development plan was proposed.

  7. IMPROVEMENT OF SLAB REHEATING PROCESS AT USIMINAS THROUGH MATHEMATICAL SIMULATION

    Directory of Open Access Journals (Sweden)

    Antônio Adel dos Santos

    2012-09-01

    Full Text Available Basic characteristics and application examples of the mathematical simulator for reheating process in walking-beam type furnaces, that has been developed and applied to Usiminas plate mill line at Ipatinga, are shown in this paper. This is a bi-dimensional mathematical model solved by the finite volume method, validated by temperature measurements inside the slab during heating and coded as a visual tool. Among these applications, the following can be highlighted: (i determination of suitable furnace zone temperatures and residence times for processing steels by accelerated cooling technology; (ii determination of slab average temperature at discharging as well as at each zone exit, supplying data to be fed to the automation system at the comissioning stage; (iii analyses of slab thermal distribution through the reheating process, enabling operational optimization

  8. Connecting CMB anisotropy and cold dark matter phenomenology via reheating

    OpenAIRE

    Maity, Debaprasad; Saha, Pankaj

    2018-01-01

    Understanding the properties of dark matter has been proved to be one of the most challenging problems of particle phenomenology. In this paper, we tried to understand the phenomenology of dark matter in light of very well understood properties of Cosmic Microwave Background (CMB) anisotropy. To connect these two, inflation and its subsequent evolution known as reheating phase play the important role. Following previous analysis, we first established one to one correspondence between the CMB ...

  9. Development of Next Generation Heating System for Scale Free Steel Reheating

    Energy Technology Data Exchange (ETDEWEB)

    Dr. Arvind C. Thekdi

    2011-01-27

    The work carried out under this project includes development and design of components, controls, and economic modeling tools that would enable the steel industry to reduce energy intensity through reduction of scale formation during the steel reheating process. Application of scale free reheating offers savings in energy used for production of steel that is lost as scale, and increase in product yield for the global steel industry. The technology can be applied to a new furnace application as well as retrofit design for conversion of existing steel reheating furnaces. The development work has resulted in the knowledge base that will enable the steel industry and steel forging industry us to reheat steel with 75% to 95% reduction in scale formation and associated energy savings during the reheating process. Scale reduction also results in additional energy savings associated with higher yield from reheat furnaces. Energy used for steel production ranges from 9 MM Btu/ton to 16.6 MM Btu/ton or the industry average of approximately 13 MM Btu/ton. Hence, reduction in scale at reheating stage would represent a substantial energy reduction for the steel industry. Potential energy savings for the US steel industry could be in excess of 25 Trillion Btu/year when the technology is applied to all reheating processes. The development work has resulted in new design of reheating process and the required burners and control systems that would allow use of this technology for steel reheating in steel as well as steel forging industries.

  10. Reciproc blue: the new generation of reciprocation

    OpenAIRE

    Ghassan Yared

    2017-01-01

    Aim: This article introduces the Reciproc® blue system and describes the clinical technique with and without creating a glide path. Methodology: The concept of canal preparation with only one mechanical instrument used in reciprocation was introduced several years ago. Studies and clinical research have shown the efficiency and the safety of the Reciproc® instrument in the preparation of the majority of canals without creating a glide path, and in the retreatment procedure. Results: Rec...

  11. Particle creation and reheating in a braneworld inflationary scenario

    Science.gov (United States)

    Bilić, Neven; Domazet, Silvije; Djordjevic, Goran S.

    2017-10-01

    We study the cosmological particle creation in the tachyon inflation based on the D-brane dynamics in the Randall-Sundrum (RSII) model extended to include matter in the bulk. The presence of matter modifies the warp factor which results in two effects: a modification of the RSII cosmology and a modification of the tachyon potential. Besides, a string theory D-brane supports among other fields a U(1) gauge field reflecting open strings attached to the brane. We demonstrate how the interaction of the tachyon with the U(1) gauge field drives cosmological creation of massless particles and estimate the resulting reheating at the end of inflation.

  12. Reciproc blue: the new generation of reciprocation

    Directory of Open Access Journals (Sweden)

    Ghassan Yared

    2017-11-01

    Conclusions: This article introduces and describes the clinical technique with which the Reciproc® blue instrument is used, even without the need to create a glide path with manual files before using the mechanical instrument.

  13. Natural inflation from 5D SUGRA and low reheat temperature

    Directory of Open Access Journals (Sweden)

    Filipe Paccetti Correia

    2015-09-01

    Full Text Available Motivated by recent cosmological observations of a possibly unsuppressed primordial tensor component r of inflationary perturbations, we reanalyze in detail the 5D conformal SUGRA originated natural inflation model of Ref. [1]. The model is a supersymmetric variant of 5D extranatural inflation, also based on a shift symmetry, and leads to the potential of natural inflation. Coupling the bulk fields generating the inflaton potential via a gauge coupling to the inflaton with brane SM states we necessarily obtain a very slow gauge inflaton decay rate and a very low reheating temperature Tr≲O(100 GeV. Analysis of the required number of e-foldings (from the CMB observations leads to values of ns in the lower range of present Planck 2015 results. Some related theoretical issues of the construction, along with phenomenological and cosmological implications, are also discussed.

  14. Reciprocity in directed networks

    Science.gov (United States)

    Yin, Mei; Zhu, Lingjiong

    2016-04-01

    Reciprocity is an important characteristic of directed networks and has been widely used in the modeling of World Wide Web, email, social, and other complex networks. In this paper, we take a statistical physics point of view and study the limiting entropy and free energy densities from the microcanonical ensemble, the canonical ensemble, and the grand canonical ensemble whose sufficient statistics are given by edge and reciprocal densities. The sparse case is also studied for the grand canonical ensemble. Extensions to more general reciprocal models including reciprocal triangle and star densities will likewise be discussed.

  15. The dish-Rankine SCSTPE program (Engineering Experiment no. 1)

    Science.gov (United States)

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

    1980-05-01

    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.

  16. Emissions-critical charge cooling using an organic rankine cycle

    Science.gov (United States)

    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.

  17. The Value of Reciprocity

    Science.gov (United States)

    Molm, Linda D.; Schaefer, David R.; Collett, Jessica L.

    2007-01-01

    The value of reciprocity in social exchange potentially comprises both instrumental value (the value of the actual benefits received from exchange) and communicative or symbolic value (the expressive and uncertainty reduction value conveyed by features of the act of reciprocity itself). While all forms of exchange provide instrumental value, we…

  18. Reheat study and the corrosion--erosion tests at TVA's Colbert Pilot Plant

    Energy Technology Data Exchange (ETDEWEB)

    Cole, R.M.; Kelso, T.M.; Robards, R.F.

    1979-05-01

    The Tennessee Valley Authority (TVA) is actively engaged in a pilot plant program to develop and/or evaluate wet-scrubbing processes for removing sulfur dioxide (SO/sub 2/) from boiler flue gas. This program includes adjunct testing to evaluate ancillary systems and components. The Electric Power Research Institute (EPRI) funded TVA to determine the operating and heat transfer characteristics for the (1) inline-indirect steam reheater, (2) flue gas recirculation reheat system, and (3) the cyclic reheat system. Tests were also made to measure the resistance of materials of construction to erosion--corrosion by process lime/limestone slurry.

  19. Organic Rankine Cycle with Solar Heat Storage in Paraffin Way

    Directory of Open Access Journals (Sweden)

    Constantin LUCA

    2015-06-01

    Full Text Available The paper presents an electricity generation system based on an Organic Rankine Cycle and proposed storing the amount of the heat produced by the solar panels using large volume of paraffin wax. The proposed working fluid is R-134a refrigerant. The cycle operates at very low temperatures. A efficiency of 6,55% was obtained.

  20. Uniform Secondary Cooling Pattern for Minimizing Surface Reheating of the Strand During Round Bloom Continuous Casting

    Science.gov (United States)

    Fan, Helin; Long, Mujun; Yu, Sheng; Chen, Dengfu; Liu, Tao; Duan, Huamei; Chen, Huabiao

    2017-12-01

    A uniform secondary cooling pattern (USCP) for minimizing surface reheating of the strand is proposed herein, based on a two-dimensional model calibrated according to measured results. The calculated results reveal the following: appropriate extension of the secondary cooling zone significantly reduces longitudinal surface reheating of the strand; a 30° misalignment angle between two adjacent rows of nozzles in cooling zones II-V significantly reduces transverse strand surface reheating; appropriate reduction in the specific water rate significantly reduces surface reheating of the whole strand. Furthermore, a USCP was determined, including secondary cooling length of 6.07 m, misalignment angle of 30°, and specific water rate of 0.26 L kg-1. This USCP has been successfully applied in a steel plant.

  1. Standard test method for determination of "microwave safe for reheating" for ceramicware

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    2006-01-01

    1.1 This test method determines the suitability of ceramicware for use in microwave re-heating applications. Microwave ovens are mainly used for reheating and defrosting frozen foods. Severe thermal conditions can occur while reheating foods. Typical reheating of foods requires one to five min. in the microwave at the highest power settings. Longer periods than five minutes are considered cooking. Cooking test methods and standards are not addressed in this test method. Most ceramicware is minimally absorbing of the microwave energy and will not heat up significantly. Unfortunately there are some products that absorb microwave energy to a greater extent and can become very hot in the microwave and pose a serious hazard. Additionally, the nature of microwave heating introduces radiation in a non-uniform manner producing temperature differentials in the food being cooked as well as the ceramic container holding it. The differential may become great enough to thermal shock the ware and create dangerous condition...

  2. Finite Element Modeling of Reheat Stretch Blow Molding of PET

    Science.gov (United States)

    Krishnan, Dwarak; Dupaix, Rebecca B.

    2004-06-01

    Poly (ethylene terephthalate) or PET is a polymer used as a packaging material for consumer products such as beverages, food or other liquids, and in other applications including drawn fibers and stretched films. Key features that make it widely used are its transparency, dimensional stability, gas impermeability, impact resistance, and high stiffness and strength in certain preferential directions. These commercially useful properties arise from the fact that PET crystallizes upon deformation above the glass transition temperature. Additionally, this strain-induced crystallization causes the deformation behavior of PET to be highly sensitive to processing conditions. It is thus crucial for engineers to be able to predict its performance at various process temperatures, strain rates and strain states so as to optimize the manufacturing process. In addressing these issues; a finite element analysis of the reheat blow molding process with PET has been carried out using ABAQUS. The simulation employed a constitutive model for PET developed by Dupaix and Boyce et al.. The model includes the combined effects of molecular orientation and strain-induced crystallization on strain hardening when the material is deformed above the glass transition temperature. The simulated bottles were also compared with actual blow molded bottles to evaluate the validity of the simulation.

  3. [Research on Temporal and Spatial Evolution of Reheating Double-Pulse Laser-Induced Plasma].

    Science.gov (United States)

    Wang, Jing-ge; Fu, Hong-bo; Ni, Zhi-bo; He, Wen-gan; Chen, Xing-long; Dong, Feng-zhong

    2016-03-01

    In order to investigate the emission enhancement mechanisms of reheating Double Pulse Laser-Induced Breakdown Spectroscopy (DP-LIBS), single pulse LIBS (SP-LIBS) and reheating DP-LIBS were carried out on an alloy steel sample respectively. The plasma emission was collected by an Echelle spectrometer with high resolution, while the plasma structure was monitored via fast-photography. The temporal and spatial evolutio ns of the plasma generated by SP-LIBS and reheating DP-LIBS were being studied. It is found that the plasma temperature in reheating DP-LIBS was higher than that of SP-LIBS, and there was a turning point for the decay rate of plasma temperature in reheating DP-LIBS when the delay time was equal to the interpulse time of DP-LIBS. Moreover, the inte nsity of the plasma image was increased by reheating DP-LIBS, and the height and width of the central region of the plasma were increased about 23.5% and 15.1% respectively. The results of spatial distribution showed that the intensity of Fe II and N I lines in the plasma were obviously enhanced by reheating DP-LIBS when the distance from the sample surface was larger than 0.6 mm. While the intensity enhancement for Fe I lines were little, even in some positio ns the intensity of Fe I lines decreased. The plasma temperature of double-pulse configuration was about 2 000 K higher than that of SP-LIBS, and a larger hot region in the plasma was generated. It is evidenced that the emission enhancement mechanisms in reheating DP-LIBS is that the second laser pulse re-excited the plasma induced by the first laser pulse, and the higher plasma temperature resulted from the re-exciting process.

  4. Pressure at the ISM-halo interface: A reheating frequency dependence

    Directory of Open Access Journals (Sweden)

    Ćirković M.M.

    1998-01-01

    Full Text Available The dependence of the thermal pressure of hot galactic halos on a model parameter describing the frequency of major reheating episodes during galactic history is investigated. Pressure on the interface between interstellar medium and the halo gas is especially interesting, since empirical evidence here offers one of the simplest constraints on halo models. It is shown that two-phase model of Mo & Miralda-Escudé is sufficiently robust with respect to uncertainties in the average interval between reheating.

  5. Attribution and reciprocity

    DEFF Research Database (Denmark)

    Sebald, Alexander Christopher

    2010-01-01

    , in turn, influence behavior. Dufwenberg and Kirchsteiger [Dufwenberg, M., Kirchsteiger, G., 2004. A theory of sequential reciprocity. Games Econ. Behav. 47 (2), 268-298] formalize this empirical finding in their ‘theory of sequential reciprocity'. This paper extends their analysis by moves of chance. More...... precisely, an extended framework is presented which allows for the analysis of strategic interactions of reciprocal agents in situations in which material outcomes also depend on chance. Moves of chance influence the attribution of responsibilities, people's perceptions about the (un)kindness of others and...

  6. Reciprocity in EMI-EMC

    Science.gov (United States)

    Coren, Richard L.

    This paper reviews the basis of and errors in interpreting the law of reciprocity, and applies it to conducted and to radiated EMI-EMC. Conditions for reciprocity include reversibility and passivity of elements in the reciprocal system. The law is expressed in circuit form and the reciprocal signals are clearly distinguished. Symmetric and asymmetric line filters are used as examples of reciprocity in conducted interference. It is shown that an incompletely shielded circuit can be regarded as an antenna, allowing one to establish radiation reciprocity between it and a measuring antenna. Some difficulties encountered in EMI-EMC measurements, that give the impression of reciprocity being violated, are discussed.

  7. Steam-Reheat Option for Supercritical-Water-Cooled Reactors

    Science.gov (United States)

    Saltanov, Eugene

    SuperCritical-Water-cooled Reactors (SCWRs) are being developed as one of the Generation-IV nuclear-reactor concepts. Main objectives of the development are to increase thermal efficiency of a Nuclear Power Plant (NPP) and to decrease capital and operational costs. The first objective can be achieved by introducing nuclear steam reheat inside a reactor and utilizing regenerative feedwater heaters. The second objective can be achieved by designing a steam cycle that closely matches that of the mature supercritical fossil-fuelled power plants. The feasibility of these objectives is discussed. As a part of this discussion, heat-transfer calculations have been performed and analyzed for SuperCritical-Water (SCW) and SuperHeated-Steam (SHS) channels of the proposed reactor concept. In the calculations a uniform and three non-uniform Axial Heat Flux Profiles (AHFPs) were considered for six different fuels (UO2, ThO 2, MOX, UC2, UC, and UN) and at average and maximum channel power. Bulk-fluid, sheath, and fuel centerline temperatures as well as the Heat Transfer Coefficient (HTC) profiles were obtained along the fuel-channel length. The HTC values are within a range of 4.7--20 kW/m2·K and 9.7--10 kW/m2·K for the SCW and SHS channels respectively. The main conclusion is that while all the mentioned fuels may be used for the SHS channel, only UC2, UC, or UN are suitable for a SCW channel, because their fuel centerline temperatures are at least 1000°C below melting point, while that of UO2, ThO2 , and MOX may reach melting point.

  8. Rankine-Brayton engine powered solar thermal aircraft

    Science.gov (United States)

    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.

  9. Reheating mechanism of the curvaton with nonminimal derivative coupling to gravity

    Energy Technology Data Exchange (ETDEWEB)

    Qiu, Taotao [Central China Normal University, Institute of Astrophysics, Wuhan (China); Central China Normal University, Key Laboratory of Quark and Lepton Physics (MOE) and College of Physical Science and Technology, Wuhan (China); Feng, Kaixi [Chinese Academy of Sciences, Institute of Theoretical Physics, Beijing (China)

    2017-10-15

    In this paper, we continue our study of the curvaton model with nonminimal derivative coupling (NDC) to Einstein gravity proposed in our previous work (Feng in Phys Lett B 729:99, 2014; Feng and Qiu in Phys Rev D 90(12):123508, 2014), focusing on the reheating mechanism. We found that according to whether the curvaton has or has not dominated the background after the end of inflation, it will have two different behaviors of evolution, which should be the general property of the curvaton with nonminimal couplings. This will cause two different parts of reheating, which goes on via the parametric resonance process. The reheating temperature is estimated for both cases in which reheating completes before and after curvaton domination, and the constraints are quite loose compared to that of overproduction of gravitinos. Finally we investigated the evolution of curvature perturbation during reheating. We have shown both analytically and numerically that the curvature perturbation will not blow up during the resonance process. (orig.)

  10. Reciprocity in Vector Acoustics

    Science.gov (United States)

    2017-03-01

    Pekeris waveguide calculated with MMPE using scalar reciprocity. Pressure is in dB//1Pa. Velocity is in dB//1m/s. Transmission loss contours are drawn...in the shelf break environment calculated withMMPEusing scalar reciprocity. Pressure is in dB//1Pa. Velocity is in dB//1m/s. Transmission loss...infinite fluid bottom with sound speed cb and density ρb, the mode shape function is Ψm(z) = Am sin ( kzmz ) , 0 ≤ z ≤ h, (2.4) where kzm is the

  11. New bound on low reheating temperature for dark matter in models with early matter domination

    Science.gov (United States)

    Choi, Ki-Young; Takahashi, Tomo

    2017-08-01

    We investigate a new bound on the low reheating temperature in a scenario where the Universe experiences early matter domination before reheating after which the standard big bang cosmology begins. In many models of dark matter (DM), the small scale fluctuations of DM grow during the early matter-domination era and seed the formation of the ultracompact minihalos (UCMHs). Using the constraints on the number of UCMHs from gamma-ray observations, we find a lower bound on the reheating temperature between O (10 )-O (100 ) MeV for WIMP dark matter depending on the nature of DM. A similar bound could be obtained for non-WIMP dark matter by observing UCMHs gravitationally such as pulsar timing, microlensing and so on, in some future observations.

  12. Number theory and modular forms papers in memory of Robert A Rankin

    CERN Document Server

    Ono, Ken

    2003-01-01

    Robert A. Rankin, one of the world's foremost authorities on modular forms and a founding editor of The Ramanujan Journal, died on January 27, 2001, at the age of 85. Rankin had broad interests and contributed fundamental papers in a wide variety of areas within number theory, geometry, analysis, and algebra. To commemorate Rankin's life and work, the editors have collected together 25 papers by several eminent mathematicians reflecting Rankin's extensive range of interests within number theory. Many of these papers reflect Rankin's primary focus in modular forms. It is the editors' fervent hope that mathematicians will be stimulated by these papers and gain a greater appreciation for Rankin's contributions to mathematics. This volume would be an inspiration to students and researchers in the areas of number theory and modular forms.

  13. Impact of different fules on reheat and nonreheat combined cycle plant performance

    Energy Technology Data Exchange (ETDEWEB)

    Tawney, R.K.; Kamali, K. (Bechtel Power Corp., Gaithersburg, MD (USA)); Yeager, W.L. (Florida Power and Light Co., Juno Beach, FL (USA))

    1988-01-01

    The combustion turbine is capable of firing a variety of gaseous and/or liquid fuels. This ability offers the power industry the advantage of utilizing the most economical fuel available in the market. The purpose of this paper is to evaluate qualitative and quantitative performance differences of combined cycle reheat versus non-reheat configurations when burning three different fuels--natural gas, distillate fuel, and coal-derived gas (coal gas). The performance data include power output, heat rates, steam produced, stack temperatures and other associated design factors.

  14. Minimal supersymmetric Higgs bosons with extra dimensions as the source of reheating and all matter.

    Science.gov (United States)

    Enqvist, Kari; Kasuya, Shinta; Mazumdar, Anupam

    2004-08-06

    We consider the possibility that the dark energy responsible for inflation is deposited into extra dimensions outside of our observable Universe. Reheating and all matter can then be obtained from the minimal supersymmetric standard model flat direction condensate involving the Higgs bosons Hu and Hd, which acquires large amplitude by virtue of quantum fluctuations during inflation. The reheat temperature is TRH < or = 10(9) GeV so that there is no gravitino problem. We find a spectral index ns 1 with a very weak dependence on the Higgs potential.

  15. Thermal Efficiency of Cogeneration Units with Multi-Stage Reheating for Russian Municipal Heating Systems

    Directory of Open Access Journals (Sweden)

    Evgeny Lisin

    2016-04-01

    Full Text Available This paper explores the layout of an optimum process for supplying heat to Russian municipal heating systems operating in a market environment. We analyze and compare the standard cogeneration unit design with two-stage reheating of service water coming from controlled extraction locations and layouts that employ three in-line reheaters with heat the supply controlled by a rotary diaphragm and qualitative/quantitative methods (so-called “uncontrolled extraction”. Cogeneration unit designs are benchmarked in terms of their thermal efficiency expressed as a fuel consumption rate. The specific fuel consumption rate on electricity production is viewed as a key parameter of thermal efficiency.

  16. Rethinking Racism in Claudia Rankine's Citizen: An American Lyric

    OpenAIRE

    Hersi, Asli

    2016-01-01

    The issue of race in America in the twenty-first century is still a turbulent matter. The end of segregation in schools, politics, marriages and workplaces created a mask that hid racial inequalities and injustices (Whitmarsh 1). In a time where police brutalities have frequently surfaced in the media in a supposed “post-racial America”, Claudia Rankine writes a thought-provoking 160 page long “book-length poem” about everyday racism arguing that the overlooking of microaggressions (brief dai...

  17. Rethinking Racism in Claudia Rankine's Citizen: An American Lyric

    OpenAIRE

    Hersi, Asli

    2016-01-01

    Master's thesis in Literacy studies The issue of race in America in the twenty-first century is still a turbulent matter. The end of segregation in schools, politics, marriages and workplaces created a mask that hid racial inequalities and injustices (Whitmarsh 1). In a time where police brutalities have frequently surfaced in the media in a supposed “post-racial America”, Claudia Rankine writes a thought-provoking 160 page long “book-length poem” about everyday racism arguing that the ove...

  18. Organic Rankine Cycle System Analysis for Low GWP Working Fluids

    OpenAIRE

    Datla, Bala Varma; Brasz, Joost

    2012-01-01

    The last decade has seen a substantial increase in Organic Rankine Cycle system installations for low temperature waste heat power recovery. The availability of HFC245fa has played a major role in this recent surge in ORC systems since it allows the use of existing HVAC hardware (heat exchangers and compressors) to be used as ORC components (turbines, boilers and condensers) with minimal redesign. The environmental drawback of HFC245fa is its relatively high GWP value of 950. The advent of a ...

  19. Reciprocity, World Prices and Welfare

    DEFF Research Database (Denmark)

    Raimondos-Møller, Pascalis; Woodland, Alan D.

    We examine in detail the circumstances under which reciprocity, as defined in Bagwell and Staiger (1999), leads to fixed world prices. We show that a change of tariffs satisfying reciprocity does not necessarily imply constant world prices in a world of many goods and countries. While...... it is possible to find tariff reforms that are consistent with both reciprocity and constant world prices, these reforms do not follow from the reciprocity condition, but rather from the requirement of unchanged world prices. We propose an alternative reciprocity rule that is guaranteed to raise the welfare...... of all countries, independently of whether world prices change and independently of the relative numbers of goods and countries....

  20. Cooking, storage, and reheating effect on the formation of cholesterol oxidation products in processed meat products.

    Science.gov (United States)

    Khan, Muhammad I; Min, Joong-Seok; Lee, Sang-Ok; Yim, Dong Gyun; Seol, Kuk-Hwan; Lee, Mooha; Jo, Cheorun

    2015-08-11

    Cholesterol is an important biological compound; however, its oxidation products have been proven to be harmful to human health. Cooking, storage, and reheating methods significantly affect the safety of meat products, as they contribute to the production of cholesterol oxidation products (COPs). Three cooking methods were used to cook sausages, loin ham, bacon, luncheon meat, and pressed ham, in order to investigate the effect of cooking, storage, and reheating on total cholesterol and on the formation of COPs. Cooked samples were stored at 4 °C and reheated after 3 and 6 storage days by the same cooking method or by microwaving. The samples were assessed for total lipids, cholesterol, and cholesterol oxides. The average cholesterol content in the processed meat varied from 76.0 mg/100 g to 201.70 mg/100 g. Microwaved ham showed the lowest cholesterol content compared to that of other processed meat products. Significant differences were found in cholesterol content and cholesterol oxidation products depending on cooking, storage, and reheating methods. Six cholesterol oxides were found in processed meat, of which 7β-hydroxycholesterol and α-epoxides were detected as the major oxidation products. Microwaving and oven grilling resulted in higher production of COPs in processed meat as compared with other cooking methods. Refrigerated storage tended to significantly increase the COPs content.

  1. Reheating via Gravitational Particle Production in Simple Models of Quintessence or ΛCDM Inflation

    Directory of Open Access Journals (Sweden)

    Jaume de Haro

    2017-11-01

    Full Text Available We have tested some simple Λ CDM (the same test is also valid for quintessence inflation models, imposing that they match with the recent observational data provided by the BICEP and Planck’s team and leading to a reheating temperature, which is obtained via gravitational particle production after inflation, supporting the nucleosynthesis success.

  2. The importance of longer wavelength reheating in dual-pulse laser-induced breakdown spectroscopy

    Science.gov (United States)

    Coons, R. W.; Harilal, S. S.; Hassan, S. M.; Hassanein, A.

    2012-06-01

    Dual-pulse laser-induced breakdown spectroscopy (LIBS) provides improved sensitivity compared to conventional single-pulse LIBS. We used a combination of Nd: yttrium aluminum garnet (YAG) and CO2 lasers to improve the sensitivity of LIBS. Significant emission intensity enhancement is noticed for both excited neutral lines and ionic lines for dual-pulse LIBS compared to single-pulse LIBS. However, the enhancement factor is found to be dependend on the energy levels of the lines, and resonance lines provided maximum enhancement. Our results indicate that IR reheating will cause significant improvement in sensitivity, regardless of the conditions, even with an unfocused reheating beam. The improved sensitivity with a YAG-CO2 laser combination is caused by the effective reheating of the pre-plume with a longer wavelength laser is due to efficient inverse Bremsstrahlung absorption. The role of the spot sizes, inter-pulse delay times, energies of the preheating and reheating pulses on the LIBS sensitivity improvements are discussed.

  3. Time domain Rankine-Green panel method for offshore structures

    Science.gov (United States)

    Li, Zhifu; Ren, Huilong; Liu, Riming; Li, Hui

    2017-02-01

    To solve the numerical divergence problem of the direct time domain Green function method for the motion simulation of floating bodies with large flare, a time domain hybrid Rankine-Green boundary element method is proposed. In this numerical method, the fluid domain is decomposed by an imaginary control surface, at which the continuous condition should be satisfied. Then the Rankine Green function is adopted in the inner domain. The transient free surface Green function is applied in the outer domain, which is used to find the relationship between the velocity potential and its normal derivative for the inner domain. Besides, the velocity potential at the mean free surface between body surface and control surface is directly solved by the integration scheme. The wave exciting force is computed through the convolution integration with wave elevation, by introducing the impulse response function. Additionally, the nonlinear Froude-Krylov force and hydrostatic force, which is computed under the instantaneous incident wave free surface, are taken into account by the direct pressure integration scheme. The corresponding numerical computer code is developed and first used to compute the hydrodynamic coefficients of the hemisphere, as well as the time history of a ship with large flare; good agreement is obtained with the analytical solutions as well as the available numerical results. Then the hydrodynamic properties of a FPSO are studied. The hydrodynamic coefficients agree well with the results computed by the frequency method; the influence of the time interval and the truncated time is investigated in detail.

  4. Cutting efficiency of Reciproc and waveOne reciprocating instruments.

    Science.gov (United States)

    Plotino, Gianluca; Giansiracusa Rubini, Alessio; Grande, Nicola M; Testarelli, Luca; Gambarini, Gianluca

    2014-08-01

    The aim of the present study was to evaluate the cutting efficiency of 2 new reciprocating instruments, Reciproc and WaveOne. Twenty-four new Reciproc R25 and 24 new WaveOne Primary files were activated by using a torque-controlled motor (Silver Reciproc) and divided into 4 groups (n = 12): group 1, Reciproc activated by Reciproc ALL program; group 2, Reciproc activated by WaveOne ALL program; group 3, WaveOne activated by Reciproc ALL program; and group 4, WaveOne activated by WaveOne ALL program. The device used for the cutting test consisted of a main frame to which a mobile plastic support for the handpiece is connected and a stainless steel block containing a Plexiglas block (inPlexiglass, Rome, Italy) against which the cutting efficiency of the instruments was tested. The length of the block cut in 1 minute was measured in a computerized program with a precision of 0.1 mm. Means and standard deviations of each group were calculated, and data were statistically analyzed with 1-way analysis of variance and Bonferroni test (P cutting efficiency than WaveOne Primary for both the movements used (P cutting efficiency than WaveOne instruments used with their proper reciprocating motion (P .05). Reciproc instruments demonstrated statistically higher cutting efficiency than WaveOne instruments. Copyright © 2014 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.

  5. Analysis of hot spots in boilers of organic Rankine cycle units during transient operation

    DEFF Research Database (Denmark)

    Benato, A.; Kærn, Martin Ryhl; Pierobon, Leonardo

    2015-01-01

    This paper is devoted to the investigation of critical dynamic events causing thermochemical decompositionof the working fluid in organic Rankine cycle power systems. The case study is the plant of an oiland gas platform where one of the three gas turbines is combined with an organic Rankine cycl...

  6. Design of organic Rankine cycles using a non-conventional optimization approach

    DEFF Research Database (Denmark)

    Andreasen, J. G.; Larsen, Ulrik; Haglind, F.

    2015-01-01

    The organic Rankine cycle is a suitable technology for utilizing low grade heat for electricity production. Compared to the traditional steam Rankine cycle, the organic Rankine cycle is beneficial, since it enables the choice of a working fluid which performs better than steam at low heat input...... temperatures and at lowpower outputs. Selecting the process layout of the organic Rankine cycle and the working fluid are two key design decisions which are critical for the thermodynamic and economic performance of the cycle. The prevailing approach used in the design and optimization of organic Rankine...... product of the overall heat transfer coefficient and the heat transfer area) is assigned to the cycle, while the distribution of this total UA-value to each of the heat exchangers is optimized. Optimizations are carried out for three different marine engine waste heatsources at temperatures ranging from...

  7. Energy analysis of Organic Rankine Cycles for biomass applications

    Directory of Open Access Journals (Sweden)

    Algieri Angelo

    2015-01-01

    Full Text Available The present paper aims at analysing the performances of Organic Rankine Cycles (ORCs adopted for the exploitation of the biomass resulting from the pruning residues in a 3000 hectares district in Southern Italy. A parametric energy analysis has been carried out to define the influence of the main plant operating conditions. To this purpose, both subcritical and transcritical power plants have been examined and saturated and superheated conditions at the turbine inlet have been imposed. Moreover, the effect of the working fluid, condensation temperature, and internal regeneration on system performances has been investigated. The results show that ORC plants represent an interesting and sustainable solution for decentralised and small-scale power production. Furthermore, the analysis highlights the significant impact of the maximum temperature and the noticeable effect of internal regeneration on the performances of the biomass power plants.

  8. Organic Rankine Kilowatt Isotope Power System. Final phase I report

    Energy Technology Data Exchange (ETDEWEB)

    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 system 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.

  9. Solar-powered Rankine heat pump for heating and cooling

    Science.gov (United States)

    Rousseau, J.

    1978-01-01

    The design, operation and performance of a familyy of solar heating and cooling systems are discussed. The systems feature a reversible heat pump operating with R-11 as the working fluid and using a motor-driven centrifugal compressor. In the cooling mode, solar energy provides the heat source for a Rankine power loop. The system is operational with heat source temperatures ranging from 155 to 220 F; the estimated coefficient of performance is 0.7. In the heating mode, the vapor-cycle heat pump processes solar energy collected at low temperatures (40 to 80 F). The speed of the compressor can be adjusted so that the heat pump capacity matches the load, allowing a seasonal coefficient of performance of about 8 to be attained.

  10. Structural Behaviour of Reciprocal Structures

    DEFF Research Database (Denmark)

    Parigi, Dario; Kirkegaard, Poul Henning

    2013-01-01

    The present paper focuses on the comparison of several two-dimensional and three-dimensional reciprocal configurations. The goal of such comparison is to analyse the structural behaviour when changing the geometric parameters used to describe the geometry of reciprocal structures.......The present paper focuses on the comparison of several two-dimensional and three-dimensional reciprocal configurations. The goal of such comparison is to analyse the structural behaviour when changing the geometric parameters used to describe the geometry of reciprocal structures....

  11. Affordable Rankine Cycle Waste Heat Recovery for Heavy Duty Trucks

    Energy Technology Data Exchange (ETDEWEB)

    Subramanian, Swami Nathan [Eaton Corporation

    2017-06-30

    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 to 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.

  12. Reciprocal relations in electroacoustics.

    Science.gov (United States)

    Chassagne, C; Bedeaux, D

    2014-07-28

    In a colloidal suspension, one can generate sound waves by the application of an alternating electric field (Electrokinetic Sonic Amplitude, i.e., ESA). Another phenomenon is electrophoresis (Electrophoretic Mobility, i.e., EM) where a colloidal particle moves relative to the solvent in an electric field. Vice versa one can generate electric fields or electric currents by sound waves (Colloid Vibration Potential/Current, i.e., CVP/CVI). In 1988 and 1990, O'Brien [J. Fluid Mech. 190, 71-86 (1988) and O'Brien, J. Fluid Mech. 212, 81-93 (1990)] derived a reciprocal relation between the proportionality coefficients of the EM and CVI phenomena. In this paper, we will generalize his proof by constructing the relevant entropy production from which the linear force-flux relations follow. General relations are derived for electrolyte solutions, of which colloidal suspensions are a particular case. The relations between CVI, CVP, EM, and ESA are discussed. O'Brien's reciprocal relation then follows as an Onsager relation. The relation is valid for any applied electric field frequency, particle surface charge and particle concentration (even in the presence of particle-particle interactions) provided the system is isotropic.

  13. Higgs Inflation, Reheating and Gravitino Production in No-Scale Supersymmetric GUTs

    CERN Document Server

    Ellis, John; Xianyu, Zhong-Zhi

    2016-08-30

    We extend our previous study of supersymmetric Higgs inflation in the context of no-scale supergravity and grand unification, to include models based on the flipped SU(5) and the Pati-Salam group. Like the previous SU(5) GUT model, these yield a class of inflation models whose inflation predictions interpolate between those of the quadratic chaotic inflation and Starobinsky-like inflation, while also avoiding tension with proton decay limits. We further analyse the reheating process in these models, and derive the number of $e$-folds, which is independent of the reheating temperature. We derive the corresponding predictions for the scalar tilt and the tensor-to-scalar ratio in cosmic microwave background perturbations, and also discuss gravitino production following inflation.

  14. Calculations of Inflaton Decays and Reheating: with Applications to No-Scale Inflation Models

    CERN Document Server

    Ellis, John; Nanopoulos, Dimitri V; Olive, Keith A

    2015-01-01

    We discuss inflaton decays and reheating in no-scale Starobinsky-like models of inflation, calculating the effective equation-of-state parameter, $w$, during the epoch of inflaton decay, the reheating temperature, $T_{\\rm reh}$, and the number of inflationary e-folds, $N_*$, comparing analytical approximations with numerical calculations. We then illustrate these results with applications to models based on no-scale supergravity and motivated by generic string compactifications, including scenarios where the inflaton is identified as an untwisted-sector matter field with direct Yukawa couplings to MSSM fields, and where the inflaton decays via gravitational-strength interactions. Finally, we use our results to discuss the constraints on these models imposed by present measurements of the scalar spectral index $n_s$ and the tensor-to-scalar perturbation ratio $r$, converting them into constraints on $N_*$, the inflaton decay rate and other parameters of specific no-scale inflationary models.

  15. Inflation and reheating in scale-invariant scalar-tensor gravity

    CERN Document Server

    Tambalo, Giovanni

    2016-01-01

    We consider the scale-invariant inflationary model studied in [1]. The Lagrangian includes all the scale-invariant operators that can be built with combinations of $R, R^{2}$ and one scalar field. The equations of motion show that the symmetry is spontaneously broken after an arbitrarily long inflationary period and a fundamental mass scale is generated. Upon symmetry breaking, and in the Jordan frame, both Hubble function and the scalar field undergo damped oscillations that can eventually amplify Standard Model fields and reheat the Universe. In the present work, we study in detail inflation and the reheating mechanism of this model in the Einstein frame and we compare some of the results with the latest observational data.

  16. Higgs inflation, reheating and gravitino production in no-scale Supersymmetric GUTs

    Energy Technology Data Exchange (ETDEWEB)

    Ellis, John [Theoretical Particle Physics and Cosmology Group,Department of Physics, King’s College London,London WC2R 2LS (United Kingdom); Theoretical Physics Department, CERN,CH-1211 Geneva 23 (Switzerland); He, Hong-Jian [Institute of Modern Physics and Center for High Energy Physics, Tsinghua University,Beijing 100084 (China); Center for High Energy Physics, Peking University,Beijing 100871 (China); Xianyu, Zhong-Zhi [Center of Mathematical Sciences and Applications andDepartment of Physics, Harvard University,Massachusetts 02138 (United States)

    2016-08-30

    We extend our previous study of supersymmetric Higgs inflation in the context of no-scale supergravity and grand unification, to include models based on the flipped SU(5) and the Pati-Salam group. Like the previous SU(5) GUT model, these yield a class of inflation models whose inflation predictions interpolate between those of the quadratic chaotic inflation and Starobinsky-like inflation, while avoiding tension with proton decay limits. We further analyse the reheating process in these models, and derive the number of e-folds, which is independent of the reheating temperature. We derive the corresponding predictions for the scalar tilt and the tensor-to-scalar ratio in cosmic microwave background perturbations, as well as discussing the gravitino production following inflation.

  17. Energy conservation in reheating furnaces by reducing scrap and scale formation; Kuumamuokkauksen energiasaeaestoet romun maeaeraeae ja hilseilyae vaehentaemaellae

    Energy Technology Data Exchange (ETDEWEB)

    Kivivuori, S.; Savolainen, P.; Fredriksson, J.; Paavola, J. [Helsinki Univ. of Technology, Otaniemi (Finland). Lab. of Materials Processing and Powder Metallurgy

    1996-12-31

    The main objective of the project `Energy Savings in Reheating Furnaces by Reducing Scrap and Scale Formation` is to reduce energy consumption and environmental harms in reheating and rolling of steel. This was done by analysing the different atmospheres in reheating furnaces of the steel companies participating in this project. These atmospheres were then simulated in a laboratory furnace. Scale formation tests with different steel grades were then carried out in these atmospheres. Scale removal tests were done to some steel grades too. The results showed that lower oxygen content - as expected - decreases oxidation despite the even higher carbondioxide content in the atmosphere. Lower oxygen content may cause difficulties in scale removal. This however is highly dependent on the steel grade. Heat treatment tests showed the effect of increased temperature and furnace time on decarburization. Some energy savings was obtained in fuel consumption by optimising the operation parameters and the atmosphere steadier in different reheating furnaces. (orig.)

  18. Further investigation about inflation and reheating stages based on the Planck and WMAP-9

    Science.gov (United States)

    Ghayour, Basem

    The potential V (ϕ) = λϕn is responsible for the inflation of the universe as scalar field ϕ oscillates quickly around some point where V (ϕ) has a minimum. The end of this stage has an important role on the further evolution stages of the universe. The created particles are responsible for reheating the universe at the end of this stage. The behavior of the inflation and reheating stages are often known as power law expansion S(η) ∝ η1+β, S(η) ∝ η1+βs, respectively. The reheating temperature (Trh) and βs give us valuable information about the reheating stage. Recently, people have studied about the behavior of Trh based on slow-roll inflation and initial condition of quantum normalization. It is shown that there is some discrepancy on Trh due to the amount of βs under the condition of slow-roll inflation and quantum normalization [M. Tong, Class. Quantum Grav. 30 (2013) 055013.]. Therefore, the author is believed in [M. Tong, Class. Quantum Grav. 30 (2013) 055013.] that the quantum normalization may not be a good initial condition but it seems that, we can remove this discrepancy by determining the appropriate parameter βs and hence the obtained temperatures based on the calculated βs are in favor of both mentioned conditions. Then from given βs, we can calculate Trh, tensor-to-scalar ratio r and parameters β,n based on the Planck and WMAP-9 data. The observed results of r,βs,β and n have consistency with their constrains. Also the results of Trh are in agreement with its general range and special range based on the DECIGO and BBO detectors.

  19. Supersymmetric mass spectra for gravitino dark matter with a high reheating temperature

    Energy Technology Data Exchange (ETDEWEB)

    Covi, L. [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany); Olechowski, M.; Pokorski, S.; Turzynski, K. [Warsaw Univ. (Poland). Inst. of Theoretical Physics; Wells, J.D. [European Organization for Nuclear Research (CERN), Geneva (Switzerland); Michigan Univ., Ann Arbor, MI (United States). Michigan Center for Theoretical Physics

    2010-09-15

    Supersymmetric theories with gravitino dark matter generally do not allow the high reheating temperature required by thermal leptogenesis without running afoul of relic abundance or big bang nucleosynthesis constraints. We report on a successful search for parameter space that does satisfy these requirements. The main implication is the near degeneracy of the gluino with the other neutralinos in the spectrum. The leading discovery channel at the LHC for this scenario is through monojet plus missing energy events. (orig.)

  20. Direct reciprocity in structured populations

    NARCIS (Netherlands)

    van Veelen, C.M.; García, J.; Rand, D.G.; Nowak, M.A.

    2012-01-01

    Reciprocity and repeated games have been at the center of attention when studying the evolution of human cooperation. Direct reciprocity is considered to be a powerful mechanism for the evolution of cooperation, and it is generally assumed that it can lead to high levels of cooperation. Here we

  1. An investigation of reheat cracking in the weld heat affected zone of type 347 stainless steel

    Science.gov (United States)

    Phung-On, Isaratat

    2007-12-01

    Reheat cracking has been a persistent problem for welding of many alloys such as the stabilized stainless steels: Types 321 and 347 as well as Cr-Mo-V steels. Similar problem occurs in Ni-base superalloys termed "strain-age cracking". Cracking occurs during the post weld heat treatment. The HAZ is the most susceptible area due to metallurgical reactions in solid state during both heating and cooling thermal cycle. Many investigations have been conducted to understand the RHC mechanism. There is still no comprehensive mechanism to explain its underlying mechanism. In this study, there were two proposed cracking mechanisms. The first is the formation of a PFZ resulting in local weakening and strain localization. The second is the creep-like grain boundary sliding that causes microvoid formation at the grain boundaries and the triple point junctions. Cracking occurs due to the coalescence of the microvoids that form. In this study, stabilized grade stainless steel, Type 347, was selected for investigation of reheat cracking mechanism due to the simplicity of its microstructure and understanding of its metallurgical behavior. The Gleeble(TM) 3800 system was employed due to its capability for precise control of both thermal and mechanical simulation. Cylindrical samples were subjected to thermal cycles for the HAZ simulation followed by PWHT as the reheat cracking test. "Susceptibility C-curves" were plotted as a function of PWHT temperatures and time to failure at applied stress levels of 70% and 80% yield strength. These C-curves show the possible relationship of the reheat cracking susceptibility and carbide precipitation behavior. To identify the mechanism, the sample shape was modified containing two flat surfaces at the center section. These flat surfaces were electro-polished and subjected to the HAZ simulation followed by the placement of the micro-indentation arrays. Then, the reheat cracking test was performed. The cracking mechanism was identified by tracing

  2. Fluid dynamics simulation of the reheating furnace of the continuous mill line of VBM

    Energy Technology Data Exchange (ETDEWEB)

    Soares, Lis Nunes; Silva, Ricardo Junqueira [V e M do Brasil S.A., Belo Horizonte. MG (Brazil)

    2009-11-01

    V and M do Brazil is an integrated steel mill with the production of seamless steel pipe. The manufacture process comprises heating and reheating fuel fired furnaces within two rolling mills lines. The Continuous Mill line reheating furnace has no baffle between heating and soaking zone that might cause a thermofluidodynamics influence between control zones and consequently an overall unbalance within the furnace. The combustion control mesh is based at the real measured temperature per zone. If the thermocouples of the heating zone are influenced by the heat flux coming from the soaking zone, the mesh might receive a wrong temperature signal and send to the heating zone burners a lower thermal demand than the real needed one. The flux unbalance may cause homogeneity problems and/or early equipment worn out. Using the software FLUENT, it was made a 2D fluid dynamic simulation of the reheating furnace with and without a baffle in order to have a qualitative view of its influence in the hot gas flux inside the furnace. Through the simulation it was possible to check the furnace homogeneity gain potential with the installation of the baffle and its better position. The results of this study supported the company decision to actually invest in a baffle installation in this furnace. Further studies will be done to quantify the results of the process. (author)

  3. FLUOROETHERS AS A WORKING FLUIDS FOR LOW TEMPERATURE ORGANIC RANKINE CYCLE

    Directory of Open Access Journals (Sweden)

    Artemenko S.V

    2014-12-01

    Full Text Available Hydrofluoroethers as a new class of working fluids for the organic Rankine cycle have been considered to utilize the low-potential waste heat. Temperature range 300…400 K was chosen to provide energy conversion of waste heat from fuel cells. The direct assessment of the efficiency criteria for the Rankine cycle via artificial neural networks (ANN was used. To create ANN the critical parameters of substance and normal boiling temperature as input were chosen. The forecast of efficiency criteria for the Rankine cycle as output parameter which reproduces the coefficient of performance with high accuracy and without thermodynamic property calculations was presented.

  4. Effect of Dynamic Reheating Induced by Weaving on the Microstructure of GTAW Weld Metal of 25% Cr Super Duplex Stainless Steel Weld Metal

    Directory of Open Access Journals (Sweden)

    Hee-Joon Sung

    2017-11-01

    Full Text Available The importance of the additional growth and/or transformation of the austenite phase that occurs in weld metals of super duplex stainless steel upon reheating is known. However, the effects have not been fully investigated, especially with respect to reheating induced by weaving during single-pass welding. In this work, bead-on-pipe gas tungsten arc welding (GTAW was conducted on super duplex stainless steel to understand the effect of weaving on the microstructure of weld metal. Microstructural analysis, electron backscatter diffraction (EBSD, and focused ion beam transmission electron microscopy (FIB-TEM were carried out to investigate the relationship between weaving and microstructural change. The weaving of GTAW produced a dynamic reheated area just before the weld bead during welding. It was revealed that extensive reheated weld existed even after one welding pass, and that the content of the austenite phase in the reheated area was higher than that in the non-reheated area, indicating the existence of a large quantity of intragranular austenite phase. In addition, the Cr2N content in the reheated area was lower than that in the non-reheated area. This reduction of Cr2N was closely related to the reheating resulting from weaving. TEM analysis revealed that Cr2N in the non-reheated area was dispersed following heating and transformed to secondary austenite.

  5. Cyclic Fatigue Resistance of Reciproc Blue, Reciproc, and WaveOne Gold Reciprocating Instruments.

    Science.gov (United States)

    Keskin, Cangül; Inan, Uğur; Demiral, Murat; Keleş, Ali

    2017-08-01

    The aim of the present study was to compare the cyclic fatigue resistance of Reciproc Blue R25 (VDW, Munich, Germany) with Reciproc R25 (VDW) and WaveOne Gold Primary (Denstply Maillefer, Ballaigues, Switzerland). Fifteen Reciproc Blue R25, 15 Reciproc R25, and 15 WaveOne Gold Primary instruments were collected and tested in a dynamic cyclic fatigue test device, which has an artificial canal with a 60° angle of curvature and a 5-mm radius of curvature. All instruments were operated until fracture occurred, and time to fracture (TF) and the lengths of the fractured fragments were recorded. The mean and standard deviations of TF and fragment length were calculated for each reciprocating system. TF data were subjected to Kruskal-Wallis 1-way analysis of variance and the Dunn test, whereas fractured fragment length data were subjected to 1-way analysis of variance (P Reciproc Blue R25 exhibited the highest cyclic fatigue resistance (P  .05). Reciproc Blue R25 instruments had significantly higher cyclic fatigue resistance than WaveOne Gold and Reciproc R25 instruments. Copyright © 2017 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.

  6. Performance analysis a of solar driven organic Rankine cycle using multi-component working fluids

    DEFF Research Database (Denmark)

    Baldasso, E.; Andreasen, J. G.; Modi, A.

    2015-01-01

    Among the different renewable sources of energy, solar power could play a primary role in the development of a more sustainable electricity generation system. While large scale concentrated solar power plants based on the steam Rankine cycle have already been proved to be cost effective, research...... is still under progress for small scale low temperature solar-driven power plants. The steam Rankine cycle is suitable for high temperature applications, but its efficiency drastically decreases as the heat source temperature drops. In these cases a much more promising configuration is the organic Rankine...... field made of parabolic trough collectors and a recuperative organic Rankine cycle. Pressurized water is selected as heat transfer fluid and its maximum temperature is fixed to 150°C. The target power output for the plant is 100 kWel. A part load analysis is carried out in order to define the most...

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

    National Research Council Canada - National Science Library

    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...

  8. Thermodynamic analysis of a Rankine cycle powered vapor compression ice maker using solar energy

    National Research Council Canada - National Science Library

    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...

  9. Rankin-Selberg methods for closed string amplitudes

    CERN Document Server

    Pioline, Boris

    2014-01-01

    After integrating over supermoduli and vertex operator positions, scattering amplitudes in superstring theory at genus $h\\leq 3$ are reduced to an integral of a Siegel modular function of degree $h$ on a fundamental domain of the Siegel upper half plane. A direct computation is in general unwieldy, but becomes feasible if the integrand can be expressed as a sum over images under a suitable subgroup of the Siegel modular group: if so, the integration domain can be extended to a simpler domain at the expense of keeping a single term in each orbit -- a technique known as the Rankin-Selberg method. Motivated by applications to BPS-saturated amplitudes, Angelantonj, Florakis and I have applied this technique to one-loop modular integrals where the integrand is the product of a Siegel-Narain theta function times a weakly, almost holomorphic modular form. I survey our main results, and take some steps in extending this method to genus greater than one.

  10. Performance analysis of organic Rankine cycles using different working fluids

    Directory of Open Access Journals (Sweden)

    Zhu Qidi

    2015-01-01

    Full Text Available Low-grade heat from renewable or waste energy sources can be effectively recovered to generate power by an organic Rankine cycle (ORC in which the working fluid has an important impact on its performance. The thermodynamic processes of ORCs using different types of organic fluids were analyzed in this paper. The relationships between the ORC’s performance parameters (including evaporation pressure, condensing pressure, outlet temperature of hot fluid, net power, thermal efficiency, exergy efficiency, total cycle irreversible loss, and total heat-recovery efficiency and the critical temperatures of organic fluids were established based on the property of the hot fluid through the evaporator in a specific working condition, and then were verified at varied evaporation temperatures and inlet temperatures of the hot fluid. Here we find that the performance parameters vary monotonically with the critical temperatures of organic fluids. The values of the performance parameters of the ORC using wet fluids are distributed more dispersedly with the critical temperatures, compared with those of using dry/isentropic fluids. The inlet temperature of the hot fluid affects the relative distribution of the exergy efficiency, whereas the evaporation temperature only has an impact on the performance parameters using wet fluid.

  11. Deriving modified Rankin scores from medical case-records.

    Science.gov (United States)

    Quinn, Terence J; Ray, Gautamananda; Atula, Sari; Walters, Matthew R; Dawson, Jesse; Lees, Kennedy R

    2008-12-01

    Modified Rankin score (mRS) is traditionally graded using a face-to-face or telephone interview. Certain stroke assessment scales can be derived from a review of a patient's case-record alone. We hypothesized that mRS could be successfully derived from the narrative within patient case-records. Sequential patients attending our cerebrovascular outpatient clinic were included. Two independent, blinded clinicians, trained in mRS, assessed case-records to derive mRS. They scored "certainty" of their grading on a 5-point Likert scale. Agreement between derived and traditional face-to-face mRS was calculated using attribute agreement analysis. Fifty patients with a range of disabilities were included. Case-record appraisers were poor at deriving mRS (k=0.34 against standard). Derived mRS grades showed poor agreement between observers (k=0.33). There was no relationship between certainty of derived mRS and proportion of correct grades (P=0.727). Accurate mRS cannot be derived from standard hospital records. Direct mRS interview is still required for clinical trials.

  12. Organic Rankine cycle - review and research directions in engine applications

    Science.gov (United States)

    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.

  13. Biogas Engine Waste Heat Recovery Using Organic Rankine Cycle

    Directory of Open Access Journals (Sweden)

    Alberto Benato

    2017-03-01

    Full Text Available Italy is a leading country in the biogas sector. Energy crops and manure are converted into biogas using anaerobic digestion and, then, into electricity using internal combustion engines (ICEs. Therefore, there is an urgent need for improving the efficiency of these engines taking the real operation into account. To this purpose, in the present work, the organic Rankine cycle (ORC technology is used to recover the waste heat contained in the exhaust gases of a 1 MWel biogas engine. The ICE behavior being affected by the biogas characteristics, the ORC unit is designed, firstly, using the ICE nameplate data and, then, with data measured during a one-year monitoring activity. The optimum fluid and the plant configuration are selected in both cases using an “in-house” optimization tool. The optimization goal is the maximization of the net electric power while the working fluid is selected among 115 pure fluids and their mixtures. Results show that a recuperative ORC designed using real data guarantees a 30% higher net electric power than the one designed with ICE nameplate conditions.

  14. Performance Analysis of Organic Rankine-vapor Compression Ice Maker Utilizing Food Industry Waste Heat

    OpenAIRE

    Bing Hu; Yuanshu Cao; Weibin Ma

    2015-01-01

    To develop the organic Rankine-vapor compression ice maker driven by food industry exhaust gases and engine cooling water, an organic Rankine-vapor compression cycle system was employed for ice making and a thermodynamic model was developed and the effects of working fluid types, hot water temperature and condensation temperature on the system performance were analyzed and the ice making capacity from unit mass hot water and unit power waste heat were evaluated. The calculated results show th...

  15. Electromagnetic reciprocity in antenna theory

    CERN Document Server

    Stumpf, Martin

    2018-01-01

    The reciprocity theorem is among the most intriguing concepts in wave field theory and has become an integral part of almost all standard textbooks on electromagnetic (EM) theory. This book makes use of the theorem to quantitatively describe EM interactions concerning general multiport antenna systems. It covers a general reciprocity-based description of antenna systems, their EM scattering properties, and further related aspects. Beginning with an introduction to the subject, Electromagnetic Reciprocity in Antenna Theory provides readers first with the basic prerequisites before offering coverage of the equivalent multiport circuit antenna representations, EM coupling between multiport antenna systems and their EM interactions with scatterers, accompanied with the corresponding EM compensation theorems.

  16. The evolution of reciprocal sharing

    OpenAIRE

    Moore, Jim

    1984-01-01

    Genetical models of the evolution of reciprocal altruism (as distinct from cooperation, mutualism, or nepotism) have difficulty explaining the initial establishment of an altruist gene in a selfish deme. Though potential mechanisms have been suggested, there is an alternative: much "altruistic" behavior may in fact be purely selfish in origin and consequently reciprocity need not be invoked to provide a selective benefit to the actor. _Sharing_ and _helping_ are fundamentally different behavi...

  17. Analysis of Low Temperature Organic Rankine Cycles for Solar Applications

    Science.gov (United States)

    Li, Yunfei

    The present work focuses on Organic Rankine Cycle (ORC) systems and their application to low temperature waste heat recovery, combined heat and power as well as off-grid solar power generation applications. As CO_2 issues come to the fore front and fossil fuels become more expensive, interest in low grade heat recovery has grown dramatically in the past few years. Solar energy, as a clean, renewable, pollution-free and sustainable energy has great potential for the use of ORC systems. Several ORC solutions have been proposed to generate electricity from low temperature sources. The ORC systems discussed here can be applied to fields such as solar thermal, biological waste heat, engine exhaust gases, small-scale cogeneration, domestic boilers, etc. The current work presents a thermodynamic and economic analysis for the use of ORC systems to convert solar energy or low exergy energy to generate electrical power. The organic working fluids investigated here were selected to investigate the effect of the fluid saturation temperature on the performance of ORCs. The working fluids under investigation are R113, R245fa, R123, with boiling points between 40°C and 200°C at pressures from 10 kPa to 10 MPa. Ambient temperature air at 20oC to 30oC is utilized as cooling resource, and allowing for a temperature difference 10°C for effective heat transfer. Consequently, the working fluids are condensed at 40°C. A combined first- and second-law analysis is performed by varying some system independent parameters at various reference temperatures. The present work shows that ORC systems can be viable and economical for the applications such as waste heat use and off-grid power generation even though they are likely to be more expensive than grid power.

  18. CMB constraints on the inflaton couplings and reheating temperature in α-attractor inflation

    Science.gov (United States)

    Drewes, Marco; Kang, Jin U.; Mun, Ui Ri

    2017-11-01

    We study reheating in α-attractor models of inflation in which the inflaton couples to other scalars or fermions. We show that the parameter space contains viable regions in which the inflaton couplings to radiation can be determined from the properties of CMB temperature fluctuations, in particular the spectral index. This may be the only way to measure these fundamental microphysical parameters, which shaped the universe by setting the initial temperature of the hot big bang and contain important information about the embedding of a given model of inflation into a more fundamental theory of physics. The method can be applied to other models of single field inflation.

  19. Advanced Natural Gas Reciprocating Engine(s)

    Energy Technology Data Exchange (ETDEWEB)

    Kwok, Doris; Boucher, Cheryl

    2009-09-30

    Energy independence and fuel savings are hallmarks of the nation’s energy strategy. The advancement of natural gas reciprocating engine power generation technology is critical to the nation’s future. A new engine platform that meets the efficiency, emissions, fuel flexibility, cost and reliability/maintainability targets will enable American manufacturers to have highly competitive products that provide substantial environmental and economic benefits in the US and in international markets. Along with Cummins and Waukesha, Caterpillar participated in a multiyear cooperative agreement with the Department of Energy to create a 50% efficiency natural gas powered reciprocating engine system with a 95% reduction in NOx emissions by the year 2013. This platform developed under this agreement will be a significant contributor to the US energy strategy and will enable gas engine technology to remain a highly competitive choice, meeting customer cost of electricity targets, and regulatory environmental standard. Engine development under the Advanced Reciprocating Engine System (ARES) program was divided into phases, with the ultimate goal being approached in a series of incremental steps. This incremental approach would promote the commercialization of ARES technologies as soon as they emerged from development and would provide a technical and commercial foundation of later-developing technologies. Demonstrations of the Phase I and Phase II technology were completed in 2004 and 2008, respectively. Program tasks in Phase III included component and system development and testing from 2009-2012. Two advanced ignition technology evaluations were investigated under the ARES program: laser ignition and distributed ignition (DIGN). In collaboration with Colorado State University (CSU), a laser ignition system was developed to provide ignition at lean burn and high boost conditions. Much work has been performed in Caterpillar’s DIGN program under the ARES program. This work

  20. Indirect Reciprocity; A Field Experiment.

    Directory of Open Access Journals (Sweden)

    Jacobien van Apeldoorn

    Full Text Available Indirect reciprocity involves cooperative acts towards strangers, either in response to their kindness to third parties (downstream or after receiving kindness from others oneself (upstream. It is considered to be important for the evolution of cooperative behavior amongst humans. Though it has been widely studied theoretically, the empirical evidence of indirect reciprocity has thus far been limited and based solely on behavior in laboratory experiments. We provide evidence from an online environment where members can repeatedly ask and offer services to each other, free of charge. For the purpose of this study we created several new member profiles, which differ only in terms of their serving history. We then sent out a large number of service requests to different members from all over the world. We observe that a service request is more likely to be rewarded for those with a profile history of offering the service (to third parties in the past. This provides clear evidence of (downstream indirect reciprocity. We find no support for upstream indirect reciprocity (in this case, rewarding the service request after having previously received the service from third parties, however. Our evidence of downstream indirect reciprocity cannot be attributed to reputational effects concerning one's trustworthiness as a service user.

  1. Indirect Reciprocity; A Field Experiment.

    Science.gov (United States)

    van Apeldoorn, Jacobien; Schram, Arthur

    2016-01-01

    Indirect reciprocity involves cooperative acts towards strangers, either in response to their kindness to third parties (downstream) or after receiving kindness from others oneself (upstream). It is considered to be important for the evolution of cooperative behavior amongst humans. Though it has been widely studied theoretically, the empirical evidence of indirect reciprocity has thus far been limited and based solely on behavior in laboratory experiments. We provide evidence from an online environment where members can repeatedly ask and offer services to each other, free of charge. For the purpose of this study we created several new member profiles, which differ only in terms of their serving history. We then sent out a large number of service requests to different members from all over the world. We observe that a service request is more likely to be rewarded for those with a profile history of offering the service (to third parties) in the past. This provides clear evidence of (downstream) indirect reciprocity. We find no support for upstream indirect reciprocity (in this case, rewarding the service request after having previously received the service from third parties), however. Our evidence of downstream indirect reciprocity cannot be attributed to reputational effects concerning one's trustworthiness as a service user.

  2. Reheat cracking susceptibility of P23 (7CrWVMoNb9-6) steel welds made using matching and mis-matching filler metals

    Energy Technology Data Exchange (ETDEWEB)

    Nevasmaa, Pekka; Salonen, Jorma; Auerkari, Pertti; Rantala, Juhani; Holmstroem, Stefan [VTT Technical Research Centre of Finland, Espoo (Finland)

    2010-07-01

    Reheat cracking sensitivity of 7CrWVMoNb9-6 (P23) thick-section multipass welds has been investigated by Gleeble simulation, mechanical testing, fractography and metallography. The results demonstrate that the experimental weld metal made using a high-Nb-W-Ti-B type filler metal was sensitive to reheat cracking, with a reduction of area no more than 2-3% in the BWI reheat cracking (RC) test. Welds made using a high-W -low-Ti type filler metal with Nb content similar to the parent steel, as well as welds make using a Ni-Nb-Ti-free-(W-free) type filler metal with the chemical composition closer to P24 grade material, were more ductile and crack-resistant, though with reduced cross-weld creep strength. Fractography of RC test specimens showed evidence of pronounced localisation of damage at the prior austenite grain boundaries of the thermally reheated, experimental P23 weld metal. The reheat cracking susceptibility of the less ductile weld metal was apparently related both to the chemical composition (higher B, Nb and Ti content) and sub-structural features of the coarse-grained reheated weld metal microstructure. Appropriate single- and multi-cycle thermal Gleeble simulations to produce representative HAY and reheated weld metal microstructures (as function of peak temperature), in conjunction with the BWI RC test were successfully applied to characterise the reheat cracking sensitivity of the candidate weld metals and parent steel HAZ. (orig.)

  3. Optimization of organic Rankine cycle power systems considering multistage axial turbine design

    DEFF Research Database (Denmark)

    Meroni, Andrea; Andreasen, Jesper Graa; Persico, Giacomo

    2018-01-01

    Organic Rankine cycle power systems represent a viable and efficient solution for the exploitation of medium-to-low temperature heat sources. Despite the large number of commissioned units, there is limited literature on the design and optimization of organic Rankine cycle power systems considering......-butane yields the best compromise in terms of cycle net power output, turbine cost and efficiency for the considered case study. When a conservative design approach is adopted, the turbine features a two-stage configuration with supersonic converging nozzles and post-expansion. Conversely, a single...... multistage turbine design. This work presents a preliminary design methodology and working fluid selection for organic Rankine cycle units featuring multistage axial turbines. The method is then applied to the case of waste heat recovery from a large marine diesel engine. A multistage axial turbine model...

  4. Optimization of organic Rankine cycle power systems considering multistage axial turbine design

    DEFF Research Database (Denmark)

    Meroni, Andrea; Andreasen, Jesper Graa; Persico, Giacomo

    2017-01-01

    Organic Rankine cycle power systems represent a viable and efficient solution for the exploitation of medium-to-low temperature heat sources. Despite the large number of commissioned units, there is limited literature on the design and optimization of organic Rankine cycle power systems considering......-butane yields the best compromise in terms of cycle net power output, turbine cost and efficiency for the considered case study. When a conservative design approach is adopted, the turbine features a two-stage configuration with supersonic converging nozzles and post-expansion. Conversely, a single...... multistage turbine design. This work presents a preliminary design methodology and working fluid selection for organic Rankine cycle units featuring multistage axial turbines. The method is then applied to the case of waste heat recovery from a large marine diesel engine. A multistage axial turbine model...

  5. Thermodynamic analysis of a Rankine cycle powered vapor compression ice maker using solar energy.

    Science.gov (United States)

    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.

  6. Optimal design of compact organic Rankine cycle units for domestic solar applications

    DEFF Research Database (Denmark)

    Barbazza, Luca; Pierobon, Leonardo; Mirandola, Alberto

    2014-01-01

    Organic Rankine cycle turbogenerators are a promising technology to transform the solar radiation harvested by solar collectors into electric power. The present work aims at sizing a small-scale organic Rankine cycle unit by tailoring its design for domestic solar applications. Stringent design...... solar collectors (hot water temperature equal to 75 degrees C), R1234yf is the optimal solution. The heat exchanger volume ranges between 6.0 and 23.0 dm(3), whereas the thermal efficiency is around 4.5%. R1234ze is the best working fluid employing parabolic solar collectors (hot water temperature equal...

  7. Combined Turbine and Cycle Optimization for Organic Rankine Cycle Power Systems—Part B

    DEFF Research Database (Denmark)

    La Seta, Angelo; Meroni, Andrea; Andreasen, Jesper Graa

    2016-01-01

    due to the peculiar physical properties of the working fluid and the gas-dynamic phenomena occurring in the machine. Unlike steam Rankine and Brayton engines, organic Rankine cycle expanders combine small enthalpy drops with large expansion ratios. These features yield turbine designs with few highly-loaded...... variables affecting the turbine design. Part B of this two-part paper presents the first application of a design method where the thermodynamic cycle optimization is combined with calculations of the maximum expander performance using the mean-line design tool described in part A. The high computational...

  8. Indirect Reciprocity : A Field Experiment

    NARCIS (Netherlands)

    van Apeldoorn, J.; Schram, A.

    2016-01-01

    Indirect reciprocity involves cooperative acts towards strangers, either in response to their kindness to third parties (downstream) or after receiving kindness from others oneself (upstream). It is considered to be important for the evolution of cooperative behavior amongst humans. Though it has

  9. Reciprocal Causation in Regression Analysis.

    Science.gov (United States)

    Wolfle, Lee M.

    1979-01-01

    With even the simplest bivariate regression, least-squares solutions are inappropriate unless one assumes a priori that reciprocal effects are absent, or at least implausible. While this discussion is limited to bivariate regression, the issues apply equally to multivariate regression, including stepwise regression. (Author/CTM)

  10. Antilisterial properties of marinades during refrigerated storage and microwave oven reheating against post-cooking inoculated chicken breast meat.

    Science.gov (United States)

    Fouladkhah, Aliyar; Geornaras, Ifigenia; Nychas, George-John; Sofos, John N

    2013-02-01

    This study evaluated growth of Listeria monocytogenes inoculated on cooked chicken meat with different marinades and survival of the pathogen as affected by microwave oven reheating. During aerobic storage at 7 °C, on days 0, 1, 2, 4, and 7, samples were reheated by microwave oven (1100 W) for 45 or 90 s and analyzed microbiologically. L. monocytogenes counts on nonmarinated (control) samples increased (P juice were not different (P ≥ 0.05; 6.9 ± 0.1 log CFU/g) from those of the control, whereas for samples treated with the remaining marinades, pathogen counts were 0.7 (soy sauce) to 2.0 (lemon juice) log CFU/g lower (P monocytogenes counts by 1.9 to 4.1 (45 s) and >2.4 to 5.0 (90 s) log CFU/g. With similar trends across different marinates, the high levels of L. monocytogenes survivors found after microwave reheating, especially after storage for more than 2 d, indicate that length of storage and reheating time need to be considered for safe consumption of leftover cooked chicken. © 2013 Institute of Food Technologists®

  11. Part-Load Performance of a Wet Indirectly Fired Gas Turbine Integrated with an Organic Rankine Cycle Turbogenerator

    DEFF Research Database (Denmark)

    Pierobon, Leonardo; Nguyen, Tuong-Van; Mazzucco, Andrea

    2014-01-01

    ) fueled by woodchips and an organic Rankine cycle (ORC) turbogenerator. An exergy analysis is performed to identify the sources of inefficiencies, the optimal design variables, and the most suitable working fluid for the organic Rankine process. This step enables to parametrize the part-load model...

  12. CFD analysis of temperature imbalance in superheater/reheater region of tangentially coal-fired boiler

    Science.gov (United States)

    Zainudin, A. F.; Hasini, H.; Fadhil, S. S. A.

    2017-10-01

    This paper presents a CFD analysis of the flow, velocity and temperature distribution in a 700 MW tangentially coal-fired boiler operating in Malaysia. The main objective of the analysis is to gain insights on the occurrences in the boiler so as to understand the inherent steam temperature imbalance problem. The results show that the root cause of the problem comes from the residual swirl in the horizontal pass. The deflection of the residual swirl due to the sudden reduction and expansion of the flow cross-sectional area causes velocity deviation between the left and right side of the boiler. This consequently results in flue gas temperature imbalance which has often caused tube leaks in the superheater/reheater region. Therefore, eliminating the residual swirl or restraining it from being diverted might help to alleviate the problem.

  13. μ -hybrid inflation with low reheat temperature and observable gravity waves

    Science.gov (United States)

    Rehman, Mansoor Ur; Shafi, Qaisar; Vardag, Fariha K.

    2017-09-01

    In μ -hybrid inflation a nonzero inflaton vacuum expectation value induced by supersymmetry breaking is proportional to the gravitino mass m3 /2, which can be exploited to resolve the minimal supersymmetric standard model μ problem. We show how this scenario can be successfully implemented with m3 /2˜1 - 100 TeV and reheat temperature as low as 1 06 GeV by employing a minimal renormalizable superpotential coupled with a well-defined nonminimal Kähler potential. The tensor-to-scalar ratio r , a canonical measure of primordial gravity waves, in most cases is less than or of the order of 10-6- 10-3 .

  14. Automatic Generation Control Study in Two Area Reheat Thermal Power System

    Science.gov (United States)

    Pritam, Anita; Sahu, Sibakanta; Rout, Sushil Dev; Ganthia, Sibani; Prasad Ganthia, Bibhu

    2017-08-01

    Due to industrial pollution our living environment destroyed. An electric grid system has may vital equipment like generator, motor, transformers and loads. There is always be an imbalance between sending end and receiving end system which cause system unstable. So this error and fault causing problem should be solved and corrected as soon as possible else it creates faults and system error and fall of efficiency of the whole power system. The main problem developed from this fault is deviation of frequency cause instability to the power system and may cause permanent damage to the system. Therefore this mechanism studied in this paper make the system stable and balance by regulating frequency at both sending and receiving end power system using automatic generation control using various controllers taking a two area reheat thermal power system into account.

  15. Application of Advanced Process Control techniques to a pusher type reheating furnace

    Science.gov (United States)

    Zanoli, S. M.; Pepe, C.; Barboni, L.

    2015-11-01

    In this paper an Advanced Process Control system aimed at controlling and optimizing a pusher type reheating furnace located in an Italian steel plant is proposed. The designed controller replaced the previous control system, based on PID controllers manually conducted by process operators. A two-layer Model Predictive Control architecture has been adopted that, exploiting a chemical, physical and economic modelling of the process, overcomes the limitations of plant operators’ mental model and knowledge. In addition, an ad hoc decoupling strategy has been implemented, allowing the selection of the manipulated variables to be used for the control of each single process variable. Finally, in order to improve the system flexibility and resilience, the controller has been equipped with a supervision module. A profitable trade-off between conflicting specifications, e.g. safety, quality and production constraints, energy saving and pollution impact, has been guaranteed. Simulation tests and real plant results demonstrated the soundness and the reliability of the proposed system.

  16. Hypercharged dark matter and direct detection as a probe of reheating.

    Science.gov (United States)

    Feldstein, Brian; Ibe, Masahiro; Yanagida, Tsutomu T

    2014-03-14

    The lack of new physics at the LHC so far weakens the argument for TeV scale thermal dark matter. On the other hand, heavier, nonthermal dark matter is generally difficult to test experimentally. Here we consider the interesting and generic case of hypercharged dark matter, which can allow for heavy dark matter masses without spoiling testability. Planned direct detection experiments will be able to see a signal for masses up to an incredible 1010  GeV, and this can further serve to probe the reheating temperature up to about 109  GeV, as determined by the nonthermal dark matter relic abundance. The Z-mediated nature of the dark matter scattering may be determined in principle by comparing scattering rates on different detector nuclei, which in turn can reveal the dark matter mass. We will discuss the extent to which future experiments may be able to make such a determination.

  17. Observational signatures of the parametric amplification of gravitational waves during reheating after inflation

    Science.gov (United States)

    Kuroyanagi, Sachiko; Lin, Chunshan; Sasaki, Misao; Tsujikawa, Shinji

    2018-01-01

    We study the evolution of gravitational waves (GWs) during and after inflation as well as the resulting observational consequences in a Lorentz-violating massive gravity theory with one scalar (inflaton) and two tensor degrees of freedom. We consider two explicit examples of the tensor mass mg that depends either on the inflaton field ϕ or on its time derivative ϕ ˙, both of which lead to parametric excitations of GWs during reheating after inflation. The first example is Starobinsky's R2 inflation model with a ϕ -dependent mg, and the second is a low energy-scale inflation model with a ϕ ˙-dependent mg. We compute the energy density spectrum ΩGW(k ) today of the GW background. In the Starobinsky's model, we show that the GWs can be amplified up to the detectable ranges of both cosmic microwave background and DECi-hertz Interferometer Gravitational wave Observatory, but the bound from the big bang nucleosynthesis is quite tight to limit the growth. In low-scale inflation with a fast transition to the reheating stage driven by the potential V (ϕ )=M2ϕ2/2 around ϕ ≈Mpl (where Mpl is the reduced Planck mass), we find that the peak position of ΩGW(k ) induced by the parametric resonance can reach the sensitivity region of advanced LIGO for the Hubble parameter of order 1 GeV at the end of inflation. Thus, our massive gravity scenario offers exciting possibilities for probing the physics of primordial GWs at various different frequencies.

  18. Wavelength dependence of prepulse laser beams on EUV emission from CO2 reheated Sn plasma

    Science.gov (United States)

    Freeman, J. R.; Harilal, S. S.; Sizyuk, T.; Hassanein, A.; Rice, B.

    2012-03-01

    Extreme ultraviolet (EUV) emission from laser-produced plasmas (LPP) centered at 13.5 nm is considered a leading candidate for the light source in future lithography systems. Tin is currently the best material for generating this EUV emission since it emits strongly within the 13.5 nm region due to its various ionic states (Sn8+-Sn14+). Highly efficient and low-debris LPPs are a pre-requisite for their use as light sources for EUV lithography. Tin plasmas generate debris that can damage collection optics over time. Techniques to mitigate debris are needed to extend the lifetime of these components and the system. Optimization of plasma conditions is necessary for increasing EUV emission and enhancing conversion efficiency (CE). Improving the source CE is necessary in order to reduce the cost of ownership and hence, develop a commercially viable lithography system for the semiconductor industry. One method to accomplish this is to reheat pre-formed plasma with a laser pulse to enhance EUV emission. This enhancement is achieved by controlling those plasma conditions necessary for optimizing EUV emission. We investigated the role of prepulse laser wavelength on prepulse plume formation and EUV in-band signal enhancement. A 6 ns Nd:YAG laser operating at 1064 nm and 266 nm was used for generating the prepulse plume. The expanding plume was then reheated by a 35 ns CO2 laser operating at 10.6 μm. The role of prepulse wavelength and energy on EUV conversion efficiency is discussed.

  19. A Comparison of Organic and Steam Rankine Cycle Power Systems for Waste Heat Recovery on Large Ships

    DEFF Research Database (Denmark)

    Andreasen, Jesper Graa; Meroni, Andrea; Haglind, Fredrik

    2017-01-01

    %) fuel case. The processes were compared based on their off-design performance for diesel engine loads in the range between 25% and 100%. The fluids considered in the organic Rankine cycle process were MM(hexamethyldisiloxane), toluene, n-pentane, i-pentane and c-pentane. The results of the comparison...... indicate that the net power output of the steam Rankine cycle process is higher at high engine loads, while the performance of the organic Rankine cycle units is higher at lower loads. Preliminary turbine design considerations suggest that higher turbine efficiencies can be obtained for the ORC unit......This paper presents a comparison of the conventional dual pressure steam Rankine cycle process and the organic Rankine cycle process for marine engine waste heat recovery. The comparison was based on a container vessel, and results are presented for a high-sulfur (3 wt %) and low-sulfur (0.5 wt...

  20. Reciprocal Teaching: Critical Reflection on Practice

    Science.gov (United States)

    McAllum, Ruth

    2014-01-01

    This paper highlights reciprocal teaching as an inclusive instructional strategy that has been shown to improve reading comprehension and metacognitive skills. It provides a conceptual background to reciprocal teaching and examines its purpose, strengths and weaknesses. The notion of reciprocal teaching as an evidence-based practice is also…

  1. Capuchin Monkeys Judge Third-Party Reciprocity

    Science.gov (United States)

    Anderson, James R.; Takimoto, Ayaka; Kuroshima, Hika; Fujita, Kazuo

    2013-01-01

    Increasing interest is being shown in how children develop an understanding of reciprocity in social exchanges and fairness in resource distribution, including social exchanges between third parties. Although there are descriptions of reciprocity on a one-to-one basis in other species, whether nonhumans detect reciprocity and violations of…

  2. Laboratory Test of Reciprocating Internal Combustion Engines

    Science.gov (United States)

    2016-02-04

    700, Laboratory Tests of Reciprocating Internal Combustion Engines , dated 24 January 1985. Marginal notations are not used in this revision to...performance and endurance of reciprocating internal combustion engines . Test equipment includes engine dynamometers, precision fuel flow meters, oil...D-1 *This TOP supersedes TOP 02-2-700, Laboratory Tests of Reciprocating Internal Combustion Engines , dated 24

  3. Final Report. Conversion of Low Temperature Waste Heat Utilizing Hermetic Organic Rankine Cycle

    Energy Technology Data Exchange (ETDEWEB)

    Fuller, Robert L.

    2005-04-20

    The design of waste heat recovery using the organic Rankine cycle (ORC) engine is updated. Advances in power electronics with lower cost enable the use of a single shaft, high-speed generator eliminating wear items and allowing hermetic sealing of the working fluid. This allows maintenance free operation and a compact configuration that lowers cost, enabling new market opportunities.

  4. Method of optimizing performance of Rankine cycle power plants. [US DOE Patent

    Science.gov (United States)

    Pope, W.L.; Pines, H.S.; Doyle, P.A.; Silvester, L.F.

    1980-06-23

    A method is described for efficiently operating a Rankine cycle power plant to maximize fuel utilization efficiency or energy conversion efficiency or minimize costs by selecting a turbine fluid inlet state which is substantially on the area adjacent and including the transposed critical temperature line.

  5. Theoretical and experimental research of organic Rankine cycle steam turbine plants

    Science.gov (United States)

    Kishkin, A. A.; Delkov, A. V.; Melkozerov, M. G.

    2017-10-01

    Currently steam power cycles using organic actuation fluid - Freon, ammonia, ethanol, isobutene, etc are becoming increasingly important. Such cycles are called Organic Rankine Cycle (ORC). With the help of such cycles it is possible to use low-grade heat sources in the production of mechanical and electrical energy.

  6. Using reciprocity in Boundary Element Calculations

    DEFF Research Database (Denmark)

    Juhl, Peter Møller; Cutanda Henriquez, Vicente

    2010-01-01

    as the reciprocal radiation problem. The present paper concerns the situation of having a point source (which is reciprocal to a point receiver) at or near a discretized boundary element surface. The accuracy of the original and the reciprocal problem is compared in a test case for which an analytical solution......The concept of reciprocity is widely used in both theoretical and experimental work. In Boundary Element calculations reciprocity is sometimes employed in the solution of computationally expensive scattering problems, which sometimes can be more efficiently dealt with when formulated...

  7. Cyclic Fatigue Resistance of Reciproc Blue and Reciproc Files in an S-shaped Canal.

    Science.gov (United States)

    Topçuoğlu, Hüseyin Sinan; Topçuoğlu, Gamze

    2017-10-01

    This study evaluated the cyclic fatigue resistance (CFR) of Reciproc (R25 and R40; VDW, Munich, Germany) and Reciproc Blue (R25 and R40, VDW) instruments used in an artificial S-shaped canal. A total of 80 files were tested in an S-shaped canal (n = 20 for each file, Reciproc R25 and R40 and Reciproc Blue R25 and R40). This study compared Reciproc R25 with Reciproc Blue R25 files and Reciproc R40 with Reciproc Blue R40 files. All files were rotated in an S-shaped artificial canal until fracture. CFR was determined by recording the time to fracture in the artificial canal. The length of each fractured fragment was measured in millimeters. An independent sample t test was used to analyze the data. Between the R25 files, Reciproc Blue instruments showed significantly greater CFR than the Reciproc files in the apical and coronal curves (P Reciproc Blue instruments exhibited greater CFR in the apical and coronal curves (P Reciproc Blue files compared with the Reciproc files (P > .05). The Reciproc Blue R25 and R40 files showed greater CFR than the Reciproc R25 and R40 files in an S-shaped canal. Copyright © 2017 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.

  8. Indirect reciprocity with trinary reputations

    CERN Document Server

    Tanabe, Shoma; Masuda, Naoki

    2012-01-01

    Indirect reciprocity is a reputation-based mechanism for cooperation in social dilemma situations when individuals do not repeatedly meet. The conditions under which cooperation based on indirect reciprocity occurs has been examined in great details. Previous theoretical analysis assumed for mathematical tractability that an individual possesses a binary reputation value, i.e., good or bad, which depends on their past actions and other factors. However, in real situations, reputations of individuals may be multiple valued. Another puzzling discrepancy between the theory and experiments is the status of the so-called image scoring, in which cooperation and defection are judged to be good and bad, respectively, independent of other factors. Such an assessment rule is found in behavioral experiments, whereas it is known to be unstable in theory. In the present study, we fill both gaps by theoretical analysis of a trinary reputation model. By an exhaustive search, we identify all the cooperative and stable equili...

  9. Reciprocal food sharing in the vampire bat

    Science.gov (United States)

    Wilkinson, Gerald S.

    1984-03-01

    Behavioural reciprocity can be evolutionarily stable1-3. Initial increase in frequency depends, however, on reciprocal altruists interacting predominantly with other reciprocal altruists either by associating within kin groups or by having sufficient memory to recognize and not aid nonreciprocators. Theory thus suggests that reciprocity should evolve more easily among animals which live in kin groups. Data are available separating reciprocity from nepotism only for unrelated nonhuman animals4. Here, I show that food sharing by regurgitation of blood among wild vampire bats (Desmodus rotundus) depends equally and independently on degree of relatedness and an index of opportunity for recipro cation. That reciprocity operates within groups containing both kin and nonkin is supported further with data on the availability of blood-sharing occasions, estimates of the economics of shar ing blood, and experiments which show that unrelated bats will reciprocally exchange blood in captivity.

  10. The Principle of Structural Reciprocity

    DEFF Research Database (Denmark)

    Pugnale, Alberto; Parigi, Dario; Kirkegaard, Poul Henning

    2011-01-01

    This paper deals with the principle of structural reciprocity, considering its origins in both Occidental and Orient culture and aiming to highlight the definition, main peculiarities and interesting aspects of such concept referring to its application to the world of construction. Issues spanning...... from history, form-finding and morphology, structural behaviour and construction techniques are discussed in the paper, which should be considered as a starting point to stimulate future research and design directions/approaches....

  11. A Comparison of Organic and Steam Rankine Cycle Power Systems for Waste Heat Recovery on Large Ships

    Directory of Open Access Journals (Sweden)

    Jesper Graa Andreasen

    2017-04-01

    Full Text Available This paper presents a comparison of the conventional dual pressure steam Rankine cycle process and the organic Rankine cycle process for marine engine waste heat recovery. The comparison was based on a container vessel, and results are presented for a high-sulfur (3 wt % and low-sulfur (0.5 wt % fuel case. The processes were compared based on their off-design performance for diesel engine loads in the range between 25% and 100%. The fluids considered in the organic Rankine cycle process were MM(hexamethyldisiloxane, toluene, n-pentane, i-pentane and c-pentane. The results of the comparison indicate that the net power output of the steam Rankine cycle process is higher at high engine loads, while the performance of the organic Rankine cycle units is higher at lower loads. Preliminary turbine design considerations suggest that higher turbine efficiencies can be obtained for the ORC unit turbines compared to the steam turbines. When the efficiency of the c-pentane turbine was allowed to be 10% points larger than the steam turbine efficiency, the organic Rankine cycle unit reaches higher net power outputs than the steam Rankine cycle unit at all engine loads for the low-sulfur fuel case. The net power production from the waste heat recovery units is generally higher for the low-sulfur fuel case. The steam Rankine cycle unit produces 18% more power at design compared to the high-sulfur fuel case, while the organic Rankine cycle unit using MM produces 33% more power.

  12. Thermodynamic Analysis of a Steam Power Plant with Double Reheat and Feed Water Heaters

    Directory of Open Access Journals (Sweden)

    M. M. Rashidi

    2014-03-01

    Full Text Available A steam cycle with double reheat and turbine extraction is presented. Six heaters are used, three of them at high pressure and the other three at low pressure with deaerator. The first and second law analysis for the cycle and optimization of the thermal and exergy efficiencies are investigated. An exergy analysis is performed to guide the thermodynamic improvement for this cycle. The exergy and irreversibility analyses of each component of the cycle are determined. Effects of turbine inlet pressure, boiler exit steam temperature, and condenser pressure on the first and second laws' efficiencies are investigated. Also the best turbine extraction pressure on the first law efficiency is obtained. The results show that the biggest exergy loss occurs in the boiler followed by the turbine. The results also show that the overall thermal efficiency and the second law efficiency decrease as the condenser pressure increases for any fixed outlet boiler temperature, however, they increase as the boiler temperature increases for any condenser pressure. Furthermore, the best values of extraction pressure from high, intermediate, and low pressure turbine which give the maximum first law efficiencies are obtained based on the required heat load corresponding to each exit boiler temperature.

  13. Reheating, thermalization and non-thermal gravitino production in MSSM inflation

    Energy Technology Data Exchange (ETDEWEB)

    Ferrantelli, Andrea [Tallinn University of Technology, Faculty of Civil Engineering, Tallinn (Estonia)

    2017-10-15

    In the framework of MSSM inflation, matter and gravitino production are here investigated through the decay of the fields which are coupled to the udd inflaton, a gauge-invariant combination of squarks. After the end of inflation, the flat direction oscillates about the minimum of its potential, losing at each oscillation about 56% of its energy into bursts of gauge/gaugino and scalar quanta when crossing the origin. These particles then acquire a large inflaton VEV-induced mass and decay perturbatively into the MSSM quanta and gravitinos, transferring the inflaton energy very efficiently via instant preheating. Regarding thermalization, we show that the MSSM degrees of freedom thermalize very quickly, yet not immediately by virtue of the large vacuum expectation value of the inflaton, which breaks the SU(3){sub C} x U(1){sub Y} symmetry into a residual U(1). The energy transfer to the MSSM quanta is very efficient, since full thermalization is achieved after only O(40) complete oscillations. The udd inflaton thus provides an extremely efficient reheating of the Universe, with a temperature T{sub reh} = O(10{sup 8} GeV), which allows for instance several mechanisms of baryogenesis. We also compute the gravitino number density from the perturbative decay of the flat direction and of the SUSY multiplet. We find that the gravitinos are produced in negligible amount and satisfy cosmological bounds such as the Big Bang nucleosynthesis (BBN) and dark matter (DM) constraints. (orig.)

  14. Exergy Analysis of a Subcritical Reheat Steam Power Plant with Regression Modeling and Optimization

    Directory of Open Access Journals (Sweden)

    MUHIB ALI RAJPER

    2016-07-01

    Full Text Available In this paper, exergy analysis of a 210 MW SPP (Steam Power Plant is performed. Firstly, the plant is modeled and validated, followed by a parametric study to show the effects of various operating parameters on the performance parameters. The net power output, energy efficiency, and exergy efficiency are taken as the performance parameters, while the condenser pressure, main steam pressure, bled steam pressures, main steam temperature, and reheat steam temperature isnominated as the operating parameters. Moreover, multiple polynomial regression models are developed to correlate each performance parameter with the operating parameters. The performance is then optimizedby using Direct-searchmethod. According to the results, the net power output, energy efficiency, and exergy efficiency are calculated as 186.5 MW, 31.37 and 30.41%, respectively under normal operating conditions as a base case. The condenser is a major contributor towards the energy loss, followed by the boiler, whereas the highest irreversibilities occur in the boiler and turbine. According to the parametric study, variation in the operating parameters greatly influences the performance parameters. The regression models have appeared to be a good estimator of the performance parameters. The optimum net power output, energy efficiency and exergy efficiency are obtained as 227.6 MW, 37.4 and 36.4, respectively, which have been calculated along with optimal values of selected operating parameters.

  15. Onsager Reciprocity in Premelting Solids

    KAUST Repository

    Peppin, S. S. L.

    2009-02-01

    The diffusive motion of foreign particles dispersed in a premelting solid is analyzed within the framework of irreversible thermodynamics. We determine the mass diffusion coefficient, thermal diffusion coefficient and Soret coefficient of the particles in the dilute limit, and find good agreement with experimental data. In contrast to liquid suspensions, the unique nature of premelting solids allows us to derive an expression for the Dufour coefficient and independently verify the Onsager reciprocal relation coupling diffusion to the flow of heat. © 2009 Springer Science+Business Media, LLC.

  16. Multi-Objective Optimization of Organic Rankine Cycle Power Plants Using Pure and Mixed Working Fluids

    DEFF Research Database (Denmark)

    Andreasen, Jesper Graa; Kærn, Martin Ryhl; Pierobon, Leonardo

    2016-01-01

    For zeotropic mixtures, the temperature varies during phase change, which is opposed to the isothermal phase change of pure fluids. The use of such mixtures as working fluids in organic Rankine cycle power plants enables a minimization of the mean temperature difference of the heat exchangers......, which is beneficial for cycle performance. On the other hand, larger heat transfer surface areas are typically required for evaporation and condensation when zeotropic mixtures are used as working fluids. In order to assess the feasibility of using zeotropic mixtures, it is, therefore, important...... to consider the additional costs of the heat exchangers. In this study, we aim at evaluating the economic feasibility of zeotropic mixtures compared to pure fluids. We carry out a multi-objective optimization of the net power output and the component costs for organic Rankine cycle power plants using low...

  17. Prospects of the use of nanofluids as working fluids for organic Rankine cycle power systems

    DEFF Research Database (Denmark)

    Mondejar, Maria E.; Andreasen, Jesper G.; Regidor, Maria

    2017-01-01

    The search of novel working fluids for organic Rankine cycle power systems is driven by the recent regulations imposing additional phase-out schedules for substances with adverse environmental characteristics. Recently, nanofluids (i.e. colloidal suspensions of nanoparticles in fluids) have been...... suggested as potential working fluids for organic Rankine cycle power systems due to their enhanced thermal properties, potentially giving advantages with respect to the design of the components and the cycle performance. Nevertheless, a number of challenges concerning the use of nanofluids must...... be investigated prior to their practical use. Among other things, the trade-off between enhanced heat transfer and increased pressure drop in heat exchangers, and the impact of the nanoparticles on the working fluid thermophysical properties, must be carefully analyzed. This paper is aimed at evaluating...

  18. Equation of State Selection for Organic Rankine Cycle Modeling Under Uncertainty

    DEFF Research Database (Denmark)

    Frutiger, Jerome; O'Connell, John; Abildskov, Jens

    combustion, geothermal and solar heat sources. The working fluid is essential to the performance of the cycle. In order to evaluate and test promising fluid candidates, an appropriate Equation of State (EoS) [1] is necessary. For ORC applications, an EoS is commonly selected based on goodness-of-fits to data......In recent years there has been a great interest in the design and selection of working fluids for low-temperature Organic Rankine Cycles (ORC), to efficiently produce electrical power from waste heat from chemical engineering applications, as well as from renewable energy sources such as biomass...... cycle, all influence the model output uncertainty. The procedure is highlighted for an ORC for with a low-temperature heat source from exhaust gas from a marine diesel engine.[1] Saleh B, Koglbauer G, Wendland M, Fischer J. Working fluids for lowtemperature organic Rankine cycles. Energy 2007...

  19. Economic analysis of a dish-Rankine solar thermal power system

    Science.gov (United States)

    Pons, R. L.; Irwin, R. E.

    An analysis of the performance and costs of a first generation dish Rankine solar thermal power system for small community and industrial applications is presented. The system is of the point-focusing distributed receiver type, with distributed generation and employs multiple paraboloidal concentrators with organic Rankine cycle power conversion systems at the focus of each dish. Projected life cycle energy costs for a fully developed and mass produced system are shown to be competitive with costs projected in the near future for electricity generated by more conventional means. It is shown that: (1) the method of rating plant poer output has a minor influence on life cycle energy cost, (2) optimum dish size is greater than 12m, (3) energy cost is virtually independent of plant size above 1 MW sub e and (4) dish spacing and geometric arrangement can be optimized to reduce energy cost.

  20. Experimental Study of a Low-Temperature Power Generation System in an Organic Rankine Cycle

    DEFF Research Database (Denmark)

    Mu, Yongchao; Zhang, Yufeng; Deng, Na

    2015-01-01

    as the engine of the power generator. The style of the preheater was a shell and tube heat exchanger, which could provide a long path for the working fluid. A flooded heat exchanger with a high heat transfer coefficient was taken as the evaporator. R134a was used as working fluid for the Rankine cycle......This paper presents a new power generation system under the principle of organic Rankine cycle which can generate power with a low-temperature heat source. A prototype was built to investigate the proposed system. In the prototype, an air screw compressor was converted into an expander and used...... in the system. This study compared and analyzed the experimental performance of the prototype at different heat source temperatures. The results show that the preheater and flooded evaporator was used for sensible heating and latent heating of the working fluid, respectively, as expected. When the temperature...

  1. Combined Turbine and Cycle Optimization for Organic Rankine Cycle Power Systems—Part A

    DEFF Research Database (Denmark)

    Meroni, Andrea; La Seta, Angelo; Andreasen, Jesper Graa

    2016-01-01

    Rankine cycle power systems. In this two-part paper, an overall cycle model and a model of an axial turbine were combined in order to provide a comprehensive preliminary design of the organic Rankine cycle unit, taking into account both cycle and turbine optimal designs. Part A presents the preliminary......Axial-flow turbines represent a well-established technology for a wide variety of power generation systems. Compactness, flexibility, reliability and high efficiency have been key factors for the extensive use of axial turbines in conventional power plants and, in the last decades, in organic...... turbine design model, the details of the validation and a sensitivity analysis on the main parameters, in order to minimize the number of decision variables in the subsequent turbine design optimization. Part B analyzes the application of the combined turbine and cycle designs on a selected case study...

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

    Science.gov (United States)

    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.

  3. Application of unscented Kalman filter for condition monitoring of an organic Rankine cycle turbogenerator

    DEFF Research Database (Denmark)

    Pierobon, Leonardo; Schlanbusch, Rune; Kandepu, Rambabu

    2014-01-01

    emphasis on compactness and reliability. In such context, organic Rankine cycle turbogenerators are a promising technology. The implementation of an organic Rankine cycle unit is thus considered for the power system of the Draugen offshore platform in the northern sea, which is the case study......This work relates to a project focusing on energy optimization on offshore facilities. On oil and gas platforms it is common practice to employ gas turbines for power production. So as to increase the system performance and reduce emissions, a bottoming cycle unit can be designed with particular...... for this project. Considering the plant dynamics, it is of paramount importance to monitor the peak temperatures within the once-through boiler serving the bottoming unit to prevent the decomposition of the working fluid. This paper accordingly aims at applying the unscented Kalman filter to estimate...

  4. Investigations on the application of zeotropic fluid mixtures in the organic rankine cycle for the geothermal power generation; Untersuchung zum Einsatz von zeotropen Fluidgemischen im Organic Rankine Cycle fuer die geothermische Stromerzeugung

    Energy Technology Data Exchange (ETDEWEB)

    Heberle, Florian

    2013-04-01

    The organic rankine cycle is a thermodynamic cycle process which uses an organic fluid working fluid instead of water in comparison to the commercial rankine process. The organic rankine cycle facilitates sufficiently high pressures at moderate temperatures. The organic rankine cycle significantly expands the technically possible and economically feasible ranges of application of such heat and power processes. The geothermal power is a very attractive field of application. Thermal water with a temperature of nearly 100 Celsius can be used for the power generation by means of the organic rankine cycle. Especially zeotropic mixtures are interesting as a working fluid. This is due to a non-isothermal phase change to a temperature glide which adapts very well to the temperature progress of the heat source. The author of the book under consideration reports on the application of different mixtures in the organic rankine cycle. The evaluation is based on a thermodynamic analysis and considers also toxicological, ecologic, technical as well as economic aspects.

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

    Science.gov (United States)

    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%.

  6. System and method for regulating EGR cooling using a Rankine cycle

    Energy Technology Data Exchange (ETDEWEB)

    Ernst, Timothy C.; Morris, Dave

    2017-08-29

    This disclosure relates to a waste heat recovery (WHR) system and method for regulating exhaust gas recirculation (EGR) cooling, and more particularly, to a Rankine cycle WHR system and method, including a recuperator bypass arrangement to regulate EGR exhaust gas cooling for engine efficiency improvement and thermal management. This disclosure describes other unique bypass arrangements for increased flexibility in the ability to regulate EGR exhaust gas cooling.

  7. Exergetic Analysis of an Integrated Tri-Generation Organic Rankine Cycle

    OpenAIRE

    Ratha Z. Mathkor; Brian Agnew; Mohammed A. Al-Weshahi; Fathi Latrsh

    2015-01-01

    This paper reports on a study of the modelling, validation and analysis of an integrated 1 MW (electrical output) tri-generation system energized by solar energy. The impact of local climatic conditions in the Mediterranean region on the system performance was considered. The output of the system that comprised a parabolic trough collector (PTC), an organic Rankine cycle (ORC), single-effect desalination (SED), and single effect LiBr-H2O absorption chiller (ACH) was electrical power, distille...

  8. Comparison of Organic Rankine Cycle Under Varying Conditions Using Turbine and Twin-Screw Expanders

    OpenAIRE

    Read, M G; Smith, I.K.; Stosic, N.

    2015-01-01

    A multi-variable optimization program has been developed to investigate the performance of Organic Rankine Cycles (ORCs) for low temperature heat recovery applications. This cycle model contains detailed thermodynamic models of the system components, and the methods used to match the operation of the expander to the requirements of the cycle are described. Two types of ORC system are considered; one containing a turbine to expand dry saturated or superheated vapour, and one with a twin-screw ...

  9. Comparison of organic rankine cycle systems under varying conditions using turbine and twin-screw expanders

    OpenAIRE

    Read, M G; Smith, I.K.; Stosic, N.; Kovacevic, A.

    2016-01-01

    A multi-variable optimization program has been developed to investigate the performance of Organic Rankine Cycles (ORCs) for low temperature heat recovery applications using both turbine and twin-screw expanders when account is taken of performance variation due to changes in ambient conditions. The cycle simulation contains thermodynamic models of both types of expander. In the case of the twin-screw machine, the methods used to match the operation of the expander to the requirements of the ...

  10. Autonomous low-temperature solar Rankine cycle system for reverse osmosis desalination

    Energy Technology Data Exchange (ETDEWEB)

    Manolakos, D.; Makris, G.; Papadakis, G.; Kyritsis, S. [Agricultural University of Athens (Greece). Dept. of Agricultural Engineering; Bouzianas, K. [Hellas Energy K. Bouzianas P. Moschovitis and Co., Athens (Greece)

    2004-07-01

    The research regards the development, application testing and performance evaluation of a low temperature solar organic Rankine cycle system for Reverse Osmosis (RO) desalination. Below is given a technical description of the system under development: Thermal energy produced by the solar array evaporates the working fluid (HFC- 134a) in the evaporator surface. The super-heated vapour is driven to the expanders where the generated mechanical work produced by the Rankine cycle drives the RO unit pumps (high pressure pump, cooling water pump, feed water pump) and circulating pump. The saturated vapour at the expanders' outlet is directed to the condenser and condensates. On the condenser surface, seawater is pre-heated and directed to the seawater reservoir. Seawater pre-heating is applied to increase the fresh water recovery ratio. The seawater tank is insulated. The use of seawater on the condenser surface decreases the temperature of ''Low Temperature Reservoir'' of Rankine cycle thus a better cycle efficiency is achieved. For the prototype system 240 m2 of vacuum tube solar collectors will be deployed. The evaporator and condenser capacity is estimated to be about 100 kW. For these systems' characteristics and considering a water recovery ratio of seawater RO desalination unit of 30%, the average yearly fresh water production is estimated at 1450 m3 (or 4 m3 daily). Specific innovations of the system are: Low temperature thermal sources can be exploited efficiently for fresh water production; solar energy is used indirectly and does not heat the seawater; the RO unit is driven by mechanical work produced from the process; the system condenser acts as sea water pre-heater and this serves a double purpose; (1) increase of feed water temperature implies higher fresh water production (2) decrease of temperature of ''low temperature reservoir'' of Rankine cycle implies higher cycle efficiencies. (orig.)

  11. Optimisation robuste de turbines pour les cycles organiques de Rankine (ORC)

    OpenAIRE

    Bufi, Elio Antonio

    2016-01-01

    In recent years, the Organic Rankine Cycle (ORC) technology has received great interest from the scientific and technical community because of its capability to recover energy from low-grade heat sources. In some applications, as the Waste Heat Recovery (WHR), ORC plants need to be as compact as possible because of geometrical and weight constraints. Recently, these issues have been studied in order to promote the ORC technology for Internal Combustion Engine (ICE) applications. The idea to r...

  12. Thermodynamic Optimization of a Geothermal- Based Organic Rankine Cycle System Using an Artificial Bee Colony Algorithm

    OpenAIRE

    Osman Özkaraca; Pınar Keçebaş; Cihan Demircan; Ali Keçebaş

    2017-01-01

    Geothermal energy is a renewable form of energy, however due to misuse, processing and management issues, it is necessary to use the resource more efficiently. To increase energy efficiency, energy systems engineers carry out careful energy control studies and offer alternative solutions. With this aim, this study was conducted to improve the performance of a real operating air-cooled organic Rankine cycle binary geothermal power plant (GPP) and its components in the aspects of thermodynamic ...

  13. Working fluids selection for fishing boats waste heat powered organic Rankine-vapor compression ice maker

    Science.gov (United States)

    Bu, Xianbiao; Wang, Lingbao; Li, Huashan

    2014-10-01

    To utilize waste heat from fishing boats, an organic Rankine cycle/vapor compression cycle system was employed for ice making and a thermodynamic model was developed. Six working fluids were selected and compared in order to identify suitable working fluids which may yield high system efficiencies. The calculated results show that R600a is most suitable working fluid through comprehensive comparison of efficiency, size parameter, pressure ratio, coefficient of performance, system pressure and safety.

  14. SORCE: A design tool for solar organic Rankine cycle systems in distributed generation applications

    OpenAIRE

    Orosz, Matthew; Quoilin, Sylvain; Hemond, Harold

    2010-01-01

    Recent interest in small-scale solar thermal combined heat and power (CHP) power systems has coincided with demand growth for distributed electricity supplies in areas poorly served by centralized power stations. One potential technical approach to meeting this demand is the parabolic trough solar thermal collector coupled with an organic Rankine cycle (ORC) heat engine. Much existing research touches on aspects of the underlying physics and mechanics of this technology, but a holistic treatm...

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

    OpenAIRE

    Bing Hu; Xianbiao Bu; Weibin Ma

    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 incr...

  16. Reciprocally-Rotating Velocity Obstacles

    KAUST Repository

    Giese, Andrew

    2014-05-01

    © 2014 IEEE. Modern multi-agent systems frequently use highlevel planners to extract basic paths for agents, and then rely on local collision avoidance to ensure that the agents reach their destinations without colliding with one another or dynamic obstacles. One state-of-the-art local collision avoidance technique is Optimal Reciprocal Collision Avoidance (ORCA). Despite being fast and efficient for circular-shaped agents, ORCA may deadlock when polygonal shapes are used. To address this shortcoming, we introduce Reciprocally-Rotating Velocity Obstacles (RRVO). RRVO generalizes ORCA by introducing a notion of rotation for polygonally-shaped agents. This generalization permits more realistic motion than ORCA and does not suffer from as much deadlock. In this paper, we present the theory of RRVO and show empirically that it does not suffer from the deadlock issue ORCA has, permits agents to reach goals faster, and has a comparable collision rate at the cost of performance overhead quadratic in the (typically small) user-defined parameter δ.

  17. Indirect reciprocity with trinary reputations.

    Science.gov (United States)

    Tanabe, Shoma; Suzuki, Hideyuki; Masuda, Naoki

    2013-01-21

    Indirect reciprocity is a reputation-based mechanism for cooperation in social dilemma situations when individuals do not repeatedly meet. The conditions under which cooperation based on indirect reciprocity occurs have been examined in great details. Most previous theoretical analysis assumed for mathematical tractability that an individual possesses a binary reputation value, i.e., good or bad, which depends on their past actions and other factors. However, in real situations, reputations of individuals may be multiple valued. Another puzzling discrepancy between the theory and experiments is the status of the so-called image scoring, in which cooperation and defection are judged to be good and bad, respectively, independent of other factors. Such an assessment rule is found in behavioral experiments, whereas it is known to be unstable in theory. In the present study, we fill both gaps by analyzing a trinary reputation model. By an exhaustive search, we identify all the cooperative and stable equilibria composed of a homogeneous population or a heterogeneous population containing two types of players. Some results derived for the trinary reputation model are direct extensions of those for the binary model. However, we find that the trinary model allows cooperation under image scoring under some mild conditions. Copyright © 2012 Elsevier Ltd. All rights reserved.

  18. On the Rankin-Selberg method for higher genus string amplitudes

    CERN Document Server

    Florakis, Ioannis

    2017-01-01

    Closed string amplitudes at genus $h\\leq 3$ are given by integrals of Siegel modular functions on a fundamental domain of the Siegel upper half-plane. When the integrand is of rapid decay near the cusps, the integral can be computed by the Rankin-Selberg method, which consists of inserting an Eisenstein series $E_h(s)$ in the integrand, computing the integral by the orbit method, and finally extracting the residue at a suitable value of $s$. String amplitudes, however, typically involve integrands with polynomial or even exponential growth at the cusps, and a renormalization scheme is required to treat infrared divergences. Generalizing Zagier's extension of the Rankin-Selberg method at genus one, we develop the Rankin-Selberg method for Siegel modular functions of degree 2 and 3 with polynomial growth near the cusps. In particular, we show that the renormalized modular integral of the Siegel-Narain partition function of an even self-dual lattice of signature $(d,d)$ is proportional to a residue of the Langla...

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

    Directory of Open Access Journals (Sweden)

    Bing Hu

    2014-01-01

    Full Text Available 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.

  20. Upgrading the SPP-500-1 moisture separators-steam reheaters used in the Leningrad NPP turbine units

    Science.gov (United States)

    Legkostupova, V. V.; Sudakov, A. V.

    2015-03-01

    The specific features of existing designs of moisture separators-steam reheaters (MSRs) and experience gained with using them at nuclear power plants are considered. Main factors causing damage to and failures of MSRs are described: nonuniform distribution of wet steam flow among the separation modules, breakthrough of moisture through the separator (and sometimes also through the steam reheater), which may lead to the occurrence of additional thermal stresses and, hence, to thermal-fatigue damage to or stress corrosion cracking of metal. MSR failure results in a less efficient operation of the turbine unit as a whole and have an adverse effect on the reliability of the low-pressure cylinder's last-stage blades. By the time the design service life of the SPP-500-1 MSRs had been exhausted in power units equipped with RBMK-1000 reactors, the number of damages inflicted to both the separation part and to the pipework and heating surface tubes was so large, that a considerable drop of MSR effectiveness and turbine unit efficiency as a whole occurred. The design of the upgraded separation part used in the SPP-500-1 MSR at the Leningrad NPP is described and its effectiveness is shown, which was confirmed by tests. First, efforts taken to achieve more uniform distribution of moisture content over the perimeter and height of steam space downstream of the separation modules and to bring it to values close to the design ones were met with success. Second, no noticeable effect of the individual specific features of separation modules on the moisture content was revealed. Recommendations on elaborating advanced designs of moisture separators-steam reheaters are given: an MSR arrangement in which the separator is placed under or on the side from the steam reheater; axial admission of wet steam for ensuring its uniform distribution among the separation modules; inlet chambers with an extended preliminary separation system and devices for uniformly distributing steam flows in the

  1. Gravitino or axino dark matter with reheat temperature as high as 1016 GeV

    Science.gov (United States)

    Co, Raymond T.; D'Eramo, Francesco; Hall, Lawrence J.

    2017-03-01

    A new scheme for lightest supersymmetric particle (LSP) dark matter is introduced and studied in theories of TeV supersymmetry with a QCD axion, a, and a high reheat temperature after inflation, T R . A large overproduction of axinos ( ã) and gravitinos (\\tilde{G}) from scattering at T R , and from freeze-in at the TeV scale, is diluted by the late decay of a saxion condensate that arises from inflation. The two lightest superpartners are ã, with mass of order the TeV scale, and \\tilde{G} with mass m 3/2 anywhere between the keV and TeV scales, depending on the mediation scale of supersymmetry breaking. Dark matter contains both warm and cold components: for \\tilde{G} LSP the warm component arises from \\tilde{a}\\to \\tilde{G}a , while for ã LSP the warm component arises from \\tilde{G}\\to \\tilde{a}a . The free-streaming scale for the warm component is predicted to be of order 1 Mpc (and independent of m 3/2 in the case of \\tilde{G} LSP). T R can be as high as 1016 GeV, for any value of m 3/2, solving the gravitino problem. The PQ symmetry breaking scale V PQ depends on T R and m 3/2 and can be anywhere in the range (1010 - 1016) GeV. Detailed predictions are made for the lifetime of the neutralino LOSP decaying to ã+ h/Z and \\tilde{G}+h/Z/γ , which is in the range of (10-1 -106)m over much of parameter space. For an axion misalignment angle of order unity, the axion contribution to dark matter is sub-dominant, except when V PQ approaches 1016 GeV.

  2. Study on effective parameter of the triple-pressure reheat combined cycle performance

    Directory of Open Access Journals (Sweden)

    Ibrahim Thamir K.

    2013-01-01

    Full Text Available The thermodynamic analyses of the triple-pressure reheat combined cycle gas turbines with duct burner are presented and discussed in this paper. The overall performance of a combined cycle gas turbine power plant is influenced by the ambient temperature, compression ratio and turbine inlet temperature. These parameters affect the overall thermal efficiency, power output and the heat-rate. In this study a thermodynamic model was development on an existing actual combined cycle gas turbine (CCGT (In this case study, an effort has been made to enhance the performance of the CCGT through a parametric study using a thermodynamic analysis. The effect of ambient temperature and operation parameter, including compression ratio and turbine inlet temperature, on the overall performance of CCGT are investigated. The code of the performance model for CCGT power plant was developed utilizing the THERMOFLEX software. The simulating results show that the total power output and overall efficiency of a CCGT decrease with increase the ambient temperature because increase the consumption power in the air compressor of a GT. The totals power of a CCGT decreases with increase the compression rate, while the overall efficiency of a CCGT increases with increase the compression ratio to 21, after that the overall efficiency will go down. Far there more the turbine inlet temperature increases the both total power and overall efficiency increase, so the turbine inlet temperature has a strong effect on the overall performance of CCGT power plant. Also the simulation model give a good result compared with MARAFIQ CCGT power plant. With these variables, the turbine inlet temperature causes the greatest overall performance variation.

  3. Mechanisms of objectionable textural changes by microwave reheating of foods: a review.

    Science.gov (United States)

    Mizrahi, Shimon

    2012-01-01

    Microwave reheating, compared to a conventional method, is notorious for lack of crust formation and severe toughening of flour and starch-based products. This review discusses how the typical thermal characteristics of microwave heating are involved in affecting the texture as well as the possible role of non-thermal effects. While low surface temperature is the well known mechanism why microwave heating is incapable of crust formation, the most severe toughening problems are caused by internal boiling. Beside moisture loss, the internally generated steam causes 2 main textural effects when it is vented out. The first is the replacing of non-condensable gases (air) in the product voids with a condensable one (steam). When the latter is condensed by cooling, a vacuum may be created in the voids causing their collapse and a formation of a more compact and tougher structure. The second textural effect involves amylose extraction from starch granules and its redistribution to eventually form a rich layer on the walls of the structural foam cells of the baked goods. Relatively fast crystallization of the amylose seems to be the main cause of toughening a short while after microwave heating. This mechanism is relevant mainly to products where starch is an important structural element. Structural disruptions by localize excessive steam pressure at hot-spots are also discussed in this review as well as methods of preventing or alleviating the most objectionable textural changes. The most effective ways of preventing these undesirable changes are by avoiding internal boiling and/or by manipulating the starch content and properties. © 2011 Institute of Food Technologists®

  4. Loneliness, exchange orientation, and reciprocity in friendships

    NARCIS (Netherlands)

    Buunk, Abraham (Bram); Prins, K.S.

    Guided by equity theory this study among 185 Dutch students explored the effects of exchange orientation and reciprocity in the relationship with the best friend upon loneliness. Reciprocity was in general more common in this relationship than feeling advantaged or deprived. The association between

  5. Information seeking and reciprocity: A transformational analysis

    NARCIS (Netherlands)

    Gallucci, M.; Perugini, M.

    2003-01-01

    The motivation to reciprocate is analyzed within the framework of interdependence theory, with focus on the process of transformation of situations. A model of transformation is presented for the motivation to reciprocate and hypotheses regarding allocation behavior and information seeking are

  6. An Introduction to the Onsager Reciprocal Relations

    Science.gov (United States)

    Monroe, Charles W.; Newman, John

    2007-01-01

    The Onsager reciprocal relations are essential to multicomponent transport theory. A discussion of the principles that should be used to derive flux laws for coupled diffusion is presented here. Fluctuation theory is employed to determine the reciprocal relation for transport coefficients that characterize coupled mass and heat transfer in binary…

  7. Education, Gift and Reciprocity: A Preliminary Discussion

    Science.gov (United States)

    Sabourin, Eric

    2013-01-01

    This paper analyzes the importance and role of the reciprocity relationship in education. It presents a review on the mobilization of the principle of reciprocity--in the anthropological but also sociological and economic senses--in educational processes, especially in adult education. The study is divided into three parts. The first part analyzes…

  8. Heterogeneous noise enhances spatial reciprocity

    CERN Document Server

    Yao, Y

    2014-01-01

    Recent research has identified the heterogeneity as crucial for the evolution of cooperation in spatial population. However, the influence of heterogeneous noise is still lack. Inspired by this interesting question, in this work, we try to incorporate heterogeneous noise into the evaluation of utility, where only a proportion of population possesses noise, whose range can also be tuned. We find that increasing heterogeneous noise monotonously promotes cooperation and even translates the full defection phase (of the homogeneous version) into the complete cooperation phase. Moreover, the promotion effect of this mechanism can be attributed to the leading role of cooperators who have the heterogeneous noise. These type of cooperators can attract more agents penetrating into the robust cooperator clusters, which is beyond the text of traditional spatial reciprocity. We hope that our work may shed light on the understanding of the cooperative behavior in the society.

  9. Reciprocity Outperforms Conformity to Promote Cooperation.

    Science.gov (United States)

    Romano, Angelo; Balliet, Daniel

    2017-10-01

    Evolutionary psychologists have proposed two processes that could give rise to the pervasiveness of human cooperation observed among individuals who are not genetically related: reciprocity and conformity. We tested whether reciprocity outperformed conformity in promoting cooperation, especially when these psychological processes would promote a different cooperative or noncooperative response. To do so, across three studies, we observed participants' cooperation with a partner after learning (a) that their partner had behaved cooperatively (or not) on several previous trials and (b) that their group members had behaved cooperatively (or not) on several previous trials with that same partner. Although we found that people both reciprocate and conform, reciprocity has a stronger influence on cooperation. Moreover, we found that conformity can be partly explained by a concern about one's reputation-a finding that supports a reciprocity framework.

  10. The relationship between reciprocity and burnout in Dutch medical residents

    NARCIS (Netherlands)

    Prins, Jelle T.; Gazendam-Donofrio, Stacey M.; Dillingh, Gea S.; van de Wiel, Harry B. M.; van der Heijden, Frank M. M. A.; Hoekstra-Weebers, Josette E. H. M.

    OBJECTIVE This study examined reciprocity in medical residents' relationships with supervisors, fellow residents, nurses and patients, and associations between reciprocity and burnout. Furthermore, we considered if a discrepancy between the perceived and preferred levels of reciprocity influenced

  11. Coupling of Modular High-Temperature Gas-Cooled Reactor with Supercritical Rankine Cycle

    Directory of Open Access Journals (Sweden)

    Shutang Zhu

    2008-01-01

    Full Text Available This paper presents investigations on the possible combination of modular high-temperature gas-cooled reactor (MHTGR technology with the supercritical (SC steam turbine technology and the prospective deployments of the MHTGR SC power plant. Energy conversion efficiency of steam turbine cycle can be improved by increasing the main steam pressure and temperature. Investigations on SC water reactor (SCWR reveal that the development of SCWR power plants still needs further research and development. The MHTGR SC plant coupling the existing technologies of current MHTGR module design with operation experiences of SC FPP will achieve high cycle efficiency in addition to its inherent safety. The standard once-reheat SC steam turbine cycle and the once-reheat steam cycle with life-steam have been studied and corresponding parameters were computed. Efficiencies of thermodynamic processes of MHTGR SC plants were analyzed, while comparisons were made between an MHTGR SC plant and a designed advanced passive PWR - AP1000. It was shown that the net plant efficiency of an MHTGR SC plant can reach 45% or above, 30% higher than that of AP1000 (35% net efficiency. Furthermore, an MHTGR SC plant has higher environmental competitiveness without emission of greenhouse gases and other pollutants.

  12. Reciprocity and Ethical Tuberculosis Treatment and Control.

    Science.gov (United States)

    Silva, Diego S; Dawson, Angus; Upshur, Ross E G

    2016-03-01

    This paper explores the notion of reciprocity in the context of active pulmonary and laryngeal tuberculosis (TB) treatment and related control policies and practices. We seek to do three things: First, we sketch the background to contemporary global TB care and suggest that poverty is a key feature when considering the treatment of TB patients. We use two examples from TB care to explore the role of reciprocity: isolation and the use of novel TB drugs. Second, we explore alternative means of justifying the use of reciprocity through appeal to different moral and political theoretical traditions (i.e., virtue ethics, deontology, and consequentialism). We suggest that each theory can be used to provide reasons to take reciprocity seriously as an independent moral concept, despite any other differences. Third, we explore general meanings and uses of the concept of reciprocity, with the primary intention of demonstrating that it cannot be simply reduced to other more frequently invoked moral concepts such as beneficence or justice. We argue that reciprocity can function as a mid-level principle in public health, and generally, captures a core social obligation arising once an individual or group is burdened as a result of acting for the benefit of others (even if they derive a benefit themselves). We conclude that while more needs to be explored in relation to the theoretical justification and application of reciprocity, sufficient arguments can be made for it to be taken more seriously as a key principle within public health ethics and bioethics more generally.

  13. ADVANCED RECIPROCATING COMPRESSION TECHNOLOGY (ARCT)

    Energy Technology Data Exchange (ETDEWEB)

    Danny M. Deffenbaugh; Klaus Brun; Ralph E. Harris; J. Pete Harrell; Robert J. Mckee; J. Jeffrey Moore; Steven J. Svedeman; Anthony J. Smalley; Eugene L. Broerman; Robert A Hart; Marybeth G. Nored; Ryan S. Gernentz; Shane P. Siebenaler

    2005-12-01

    The U.S. natural gas pipeline industry is facing the twin challenges of increased flexibility and capacity expansion. To meet these challenges, the industry requires improved choices in gas compression to address new construction and enhancement of the currently installed infrastructure. The current fleet of installed reciprocating compression is primarily slow-speed integral machines. Most new reciprocating compression is and will be large, high-speed separable units. The major challenges with the fleet of slow-speed integral machines are: limited flexibility and a large range in performance. In an attempt to increase flexibility, many operators are choosing to single-act cylinders, which are causing reduced reliability and integrity. While the best performing units in the fleet exhibit thermal efficiencies between 90% and 92%, the low performers are running down to 50% with the mean at about 80%. The major cause for this large disparity is due to installation losses in the pulsation control system. In the better performers, the losses are about evenly split between installation losses and valve losses. The major challenges for high-speed machines are: cylinder nozzle pulsations, mechanical vibrations due to cylinder stretch, short valve life, and low thermal performance. To shift nozzle pulsation to higher orders, nozzles are shortened, and to dampen the amplitudes, orifices are added. The shortened nozzles result in mechanical coupling with the cylinder, thereby, causing increased vibration due to the cylinder stretch mode. Valve life is even shorter than for slow speeds and can be on the order of a few months. The thermal efficiency is 10% to 15% lower than slow-speed equipment with the best performance in the 75% to 80% range. The goal of this advanced reciprocating compression program is to develop the technology for both high speed and low speed compression that will expand unit flexibility, increase thermal efficiency, and increase reliability and integrity

  14. Pressure reciprocity calibration of a MEMS microphone.

    Science.gov (United States)

    Wagner, Randall P; Fick, Steven E

    2017-09-01

    This article reports the first use of the pressure reciprocity technique to calibrate a micro-electromechanical system (MEMS) microphone. This standardized primary calibration method is conventionally used to calibrate laboratory standard microphones. Results for the pressure reciprocity calibration of a MEMS microphone and two laboratory standard microphones are presented for the frequency range 100-10 000 Hz. Because the amplifier in the MEMS microphone package prevents reciprocal operation, this microphone was used only as a receiver of sound. A description of the procedure is presented along with checks of the measurement results and data regarding the uncertainties of these results.

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

    Science.gov (United States)

    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.

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

    Science.gov (United States)

    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.

  17. Experimental Comparison Of Working Fluids For Organic Rankine Cycle With Single-Screw Expander

    OpenAIRE

    Gusev, Sergei; Ziviani, Davide; Bell, Ian; De Paepe, Michel; van den Broek, Martijn

    2014-01-01

    This paper describes the behavior of an Organic Rankine Cycle (ORC) fed by a heat source with adaptable temperature and mass flow. For a suitable choice of working fluid, the setting of its evaporation pressure is crucial for the performance of an ORC installation. The higher the evaporation pressure, the higher the cycle efficiency on the one hand, but the lower the energy recovered from the heat source due to a higher outlet temperature on the other hand. An optimum has to be found to achie...

  18. Numerical Optimization of an Organic Rankine Cycle Scheme for Co-generation

    OpenAIRE

    Potenza, Marco; Naccarato, Fabrizio; Stigliano, Gianbattista; Risi, Arturo de

    2016-01-01

    The aim of the present work was the optimization of a small size Organic Rankine Cycle (ORC) system powered by a linear Parabolic Trough Collector (PTC) solar field by means of numerical model code developed on purpose. In the proposed scheme the solar energy is collected by a newly designed low cost PTC of 20m2 with a single tracking axis and it is concentrated on an opaque pipe collector in which flows as thermal fluid the Therminol® 66 oil. An oil-free scroll expander coupled with a 2 kW e...

  19. Theoretical study of thermally driven heat pumps based on double organic rankine cycle

    OpenAIRE

    Demierre, Jonathan; Favrat, Daniel

    2013-01-01

    Part of: Thermally driven heat pumps for heating and cooling. – Ed.: Annett Kühn – Berlin: Universitätsverlag der TU Berlin, 2013 ISBN 978-3-7983-2686-6 (print) ISBN 978-3-7983-2596-8 (online) urn:nbn:de:kobv:83-opus4-39458 [http://nbn-resolving.de/urn:nbn:de:kobv:83-opus4-39458] This study deals with a type of thermally driven heat pumps that consists of a reverse Rankine heat pump cycle, the compressor of which is driven by the turbine of a supercritical Organi...

  20. Uncertainty assessment of equations of state with application to an organic Rankine cycle

    DEFF Research Database (Denmark)

    Frutiger, Jerome; Bell, Ian; O’Connell, John P.

    2017-01-01

    Evaluations of equations of state (EoS) should include uncertainty. This study presents a genericmethod to analyse EoS from a detailed uncertainty analysis of the mathematical form and the dataused to obtain EoS parameter values. The method is illustrated by comparison of Soave–Redlich–Kwong (SRK......) cubic EoS with perturbed-chain statistical associating fluid theory (PC-SAFT) EoS for anorganic Rankine cycle (ORC) for heat recovery to power fromthe exhaust gas of a marine diesel engineusing cyclopentane as working fluid. Uncertainties of the EoS input parameters including...

  1. Conceptual design and analysis of a Dish-Rankine solar thermal power system

    Science.gov (United States)

    Pons, R. L.

    1980-08-01

    A Point Focusing Distributed Receiver (PFDR) solar thermal electric system which employs small Organic Rankine Cycle (ORC) engines is examined with reference to its projected technical/economic performance. With mass-produced power modules (about 100,000 per year), the projected life-cycle energy cost for an optimized no-storage system is estimated at 67 mills/kWh (Levelized Busbar Energy Cost) without the need for advanced development of any of its components. At moderate production rates (about 50 MWe/yr) system energy costs are competitive with conventional power generation systems in special remote-site types of applications.

  2. Panel cutting method: new approach to generate panels on a hull in Rankine source potential approximation

    Directory of Open Access Journals (Sweden)

    Hee-Jong Choi

    2011-12-01

    Full Text Available In the present study, a new hull panel generation algorithm, namely panel cutting method, was developed to predict flow phenomena around a ship using the Rankine source potential based panel method, where the iterative method was used to satisfy the nonlinear free surface condition and the trim and sinkage of the ship was taken into account. Numerical computations were performed to investigate the validity of the proposed hull panel generation algorithm for Series 60 (CB=0.60 hull and KRISO container ship (KCS, a container ship designed by Maritime and Ocean Engineering Research Institute (MOERI. The computational results were validated by comparing with the existing experimental data.

  3. Design and optimization of a novel organic Rankine cycle with improved boiling process

    DEFF Research Database (Denmark)

    Andreasen, Jesper Graa; Larsen, U.; Knudsen, Thomas

    2015-01-01

    to improve the boiling process. Optimizations are carried out for eight hydrocarbon mixtures for hot fluid inlet temperatures at 120 °C and 90 °C, using a genetic algorithm to determine the cycle conditions for which the net power output is maximized. The most promising mixture is an isobutane....../pentane mixture which, for the 90 °C hot fluid inlet temperature case, achieves a 14.5% higher net power output than an optimized organic Rankine cycle using the same mixture. Two parameter studies suggest that optimum conditions for the organic split-cycle are when the temperature profile allows the minimum...

  4. Performance analysis of different organic Rankine cycle configurations on board liquefied natural gas-fuelled vessels

    DEFF Research Database (Denmark)

    Baldasso, Enrico; Andreasen, Jesper Graa; Meroni, Andrea

    2017-01-01

    natural gas (LNG). The study compares the performance of six different ORC configurations both in design and off-design operation, and provides guidelines with respect to the most promising heat sources and sinks to be utilized by an ORC unit in order to maximize the annual fuel savings. In addition......Gas-fuelled shipping is expected to increase significantly in the coming years. Similarly, much effort is devoted to the study of waste heat recovery systems to be implemented on board ships. In this context, the organic Rankine cycle (ORC) technology is considered one of the most promising...

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

    Science.gov (United States)

    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.

  6. Preliminary design package for residential heating/cooling system--Rankine air conditioner redesign

    Energy Technology Data Exchange (ETDEWEB)

    1978-12-01

    This report contains a summary of the preliminary redesign and development of a marketable single-family heating and cooling system. The objectives discussed are 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. 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.

  7. Spite and Reciprocity in Auctions

    Directory of Open Access Journals (Sweden)

    Yoshikazu Ikeda

    2011-09-01

    Full Text Available The paper presents a complete information model of bidding in second price sealed-bid and ascending-bid (English auctions, in which potential buyers know the unit valuation of other bidders and may spitefully prefer that their rivals earn a lower surplus. Bidders with spiteful preferences should overbid in equilibrium when they know their rival has a higher value than their own, and bidders with a higher value underbid to reciprocate the spiteful overbidding of the lower value bidders. The model also predicts different bidding behavior in second price as compared to ascending-bid auctions. The paper also presents experimental evidence broadly consistent with the model. In the complete information environment, lower value bidders overbid more than higher value bidders, and they overbid more frequently in the second price auction than in the ascending price auction. Overall, the lower value bidder submits bids that exceed value about half the time. These patterns are not found in the incomplete information environment, consistent with the model.

  8. Supervision system for the plate mill reheating furnaces at Companhia Siderurgica Paulista; Sistema supervisor dos fornos de placas da linha de chapas grossas

    Energy Technology Data Exchange (ETDEWEB)

    Cardoso, Abner Cordeiro; Rother, Ariovaldo; Texeira, Aloisio; Ramos, Carlos; Masulo, Mario Donato [Companhia Siderurgica Paulista, SP (Brazil); Dias, Ronaldo Freitas [TSE Automacao Industrial, XX (Brazil)

    1997-12-31

    The Quality Assurance System required by customers from several industrial branches are forcing suppliers to spend more and more money on technological improvements. COSIPA`s Plate Mill, following this tendency, has just installed a Supervisor System for its Reheating Furnaces, which allows the acquisition and retrieving of operational data. This information makes feasible the development of studies and projects for the continuous improvement of the reheating process. This system is reliable, shows low operational coast and has easy maintenance. Finally, last but not least, t has direct data communication with the mainframe as well, enabling interaction with furnace control and, in such way, this system can determine the reheating temperatures and rolling pitch according to the production schedule. This system has also available special software for the generation of production reports according to the QAS (Quality Assurance System) and other standards. (author) 15 figs.

  9. Apparatus and methods of reheating gas turbine cooling steam and high pressure steam turbine exhaust in a combined cycle power generating system

    Science.gov (United States)

    Tomlinson, Leroy Omar; Smith, Raub Warfield

    2002-01-01

    In a combined cycle system having a multi-pressure heat recovery steam generator, a gas turbine and steam turbine, steam for cooling gas turbine components is supplied from the intermediate pressure section of the heat recovery steam generator supplemented by a portion of the steam exhausting from the HP section of the steam turbine, steam from the gas turbine cooling cycle and the exhaust from the HP section of the steam turbine are combined for flow through a reheat section of the HRSG. The reheated steam is supplied to the IP section inlet of the steam turbine. Thus, where gas turbine cooling steam temperature is lower than optimum, a net improvement in performance is achieved by flowing the cooling steam exhausting from the gas turbine and the exhaust steam from the high pressure section of the steam turbine in series through the reheater of the HRSG for applying steam at optimum temperature to the IP section of the steam turbine.

  10. The reciprocity theorem for porous anisotropic media

    Directory of Open Access Journals (Sweden)

    E. BOSCHI

    1972-06-01

    Full Text Available In this paper we give a reciprocity theorem for anisotropic
    porous media in the quasi-stationary case. The distribution of the
    pores is assumed statistically homogeneous.

  11. 78 FR 53792 - Draft Guidance for Reciprocity

    Science.gov (United States)

    2013-08-30

    ... (Reciprocity).'' The document has been updated from the previous revision to include safety culture, security... INFORMATION CONTACT: Tomas Herrera, Office of Federal and State Materials and Environmental Management... State Materials, and Environmental Management Programs. BILLING CODE 7590-01-P ...

  12. Agenda Setting and Reciprocal Vote Trading

    OpenAIRE

    Urs Fischbacher; Simeon Schudy

    2010-01-01

    We study the implications of reciprocity on agenda setting in a sequential policy decision. We designed a laboratory experiment in which a committee decides sequentially on three independent bills. Selfish committee members would turn down all bills but reCiprocity allows for implicit vote trading. This mechanism gives power to agenda setters. We find that agenda setters use their power when setting the agenda but are rather generous in the voting decision. Legislators benefiting from the cho...

  13. Balanced Reciprocal Translocations Detected at Amniocentesis

    Directory of Open Access Journals (Sweden)

    Chih-Ping Chen

    2010-12-01

    Conclusion: Balanced reciprocal translocations detected at amniocentesis may be associated with fetal anomalies in cases of concomitant aneuploidy, de novo X-autosome translocation or de novo CCR. Genetic counseling of a de novo simple reciprocal translocation at amniocentesis remains difficult because approximately one-fourth of the parents opt for termination of the pregnancy, and detailed ultrasonography and array comparative genomic hybridization are helpful for parental counseling under such circumstances.

  14. Research of efficiency of the organic Rankine cycle on a mathematical model

    Directory of Open Access Journals (Sweden)

    Galashov N.

    2017-01-01

    Full Text Available The object of the study are the organic Rankine cycle. The purpose of research is to evaluate the impact on the net efficiency of the initial and final properties of the cycle at work on a saturated and superheated steam. Investigations were carried out on the basis of a mathematical model, in which the thermodynamic properties of materials are determined on the basis of “REFPROP”. On the basis of the available scientific publications on the use of working fluids in an organic Rankine cycle analysis was selected ozone-safe pentane. A mathematical model has been developed on condition that condenser is used as air cooler which allows the substance to condense at a temperature below 0 °С. Numerical study on the mathematical model shown that net efficiency at work on pentane linearly depends on the condensation temperature and parabolically depends on the initial temperature with the saturated steam. During work at the superheated steam efficiency strongly depends on both the initial temperature and of the initial pressure. With rising initial temperature is necessary to gradually increase the initial pressure under certain conditions.

  15. Multi-Objective Optimization of Organic Rankine Cycle Power Plants Using Pure and Mixed Working Fluids

    Directory of Open Access Journals (Sweden)

    Jesper G. Andreasen

    2016-04-01

    Full Text Available For zeotropic mixtures, the temperature varies during phase change, which is opposed to the isothermal phase change of pure fluids. The use of such mixtures as working fluids in organic Rankine cycle power plants enables a minimization of the mean temperature difference of the heat exchangers, which is beneficial for cycle performance. On the other hand, larger heat transfer surface areas are typically required for evaporation and condensation when zeotropic mixtures are used as working fluids. In order to assess the feasibility of using zeotropic mixtures, it is, therefore, important to consider the additional costs of the heat exchangers. In this study, we aim at evaluating the economic feasibility of zeotropic mixtures compared to pure fluids. We carry out a multi-objective optimization of the net power output and the component costs for organic Rankine cycle power plants using low-temperature heat at 90 ∘ C to produce electrical power at around 500 kW. The primary outcomes of the study are Pareto fronts, illustrating the power/cost relations for R32, R134a and R32/R134a (0.65/0.35 mole . The results indicate that R32/R134a is the best of these fluids, with 3.4 % higher net power than R32 at the same total cost of 1200 k$.

  16. Selecting working fluids in an organic Rankine cycle for power generation from low temperature heat sources

    Directory of Open Access Journals (Sweden)

    Fredy Vélez

    2014-01-01

    Full Text Available Este trabajo presenta un estudio termodinámico realizado sobre el uso de fuentes de calor de baja temperatura para la generaci ón de energía a través de un ciclo Rankin e subcrítico con fluidos de trabajo orgánicos. Un análisis d el estado del arte de esta tecn ología muestra como línea de investigación abierta, la selección del fluido de trabajo, pues hasta ahora, no existe un fluido que satisfaga t odos los aspectos medioambientales y técnicos a tener en cuenta en estos ciclos. Por ello, se ha desarrollado una serie de simulaciones que permiten estudiar el comportamiento del ciclo Rankine con difer entes configuraciones y fluidos (húmedo, seco e isoentrópico, permitiendo con ello observar de qué manera influyen cambios ta nto en esos tipos de fluidos utilizados (refrigerantes, hidroca rburos y agua, como de condiciones de temperatura, presión, flujo, etc. , sobre la eficiencia total del ciclo. Con el trabajo realizado se demuestra la viabilidad de este tipo de proceso en la recuperación de calore s en la industria y/o aprovechamiento de fuentes renovables de baja y media temperatura para la producción de energía eléctrica.

  17. Waste Heat Recovery of a PEMFC System by Using Organic Rankine Cycle

    Directory of Open Access Journals (Sweden)

    Tianqi He

    2016-04-01

    Full Text Available In this study, two systems are brought forward to recover the waste heat of a proton exchange membrane fuel cell (PEMFC, which are named the organic Rankine cycle (ORC, and heat pump (HP combined organic Rankine cycle (HPORC. The performances of both systems are simulated on the platform of MATLAB with R123, R245fa, R134a, water, and ethanol being selected as the working fluid, respectively. The results show that, for PEMFC where operating temperature is constantly kept at 60 °C, there exists an optimum working temperature for each fluid in ORC and HPORC. In ORC, the maximal net power can be achieved with R245fa being selected as the working fluid. The corresponding thermal efficiency of the recovery system is 4.03%. In HPORC, the maximal net power can be achieved with water being selected in HP and R123 in ORC. The thermal efficiency of the recovery system increases to 4.73%. Moreover, the possibility of using ORC as the cooling system of PEMFC is also studied. The heat released from PEMFC stack is assumed to be wholly recovered by the ORC or HPORC system. The results indicate that the HPORC system is much more feasible for the cooling system of a PEMFC stack, since the heat recovery ability can be promoted due to the presence of HP.

  18. Static non-reciprocity in mechanical metamaterials

    Science.gov (United States)

    Coulais, Corentin; Sounas, Dimitrios; Alù, Andrea

    2017-02-01

    Reciprocity is a general, fundamental principle governing various physical systems, which ensures that the transfer function—the transmission of a physical quantity, say light intensity—between any two points in space is identical, regardless of geometrical or material asymmetries. Breaking this transmission symmetry offers enhanced control over signal transport, isolation and source protection. So far, devices that break reciprocity (and therefore show non-reciprocity) have been mostly considered in dynamic systems involving electromagnetic, acoustic and mechanical wave propagation associated with fields varying in space and time. Here we show that it is possible to break reciprocity in static systems, realizing mechanical metamaterials that exhibit vastly different output displacements under excitation from different sides, as well as one-way displacement amplification. This is achieved by combining large nonlinearities with suitable geometrical asymmetries and/or topological features. In addition to extending non-reciprocity and isolation to statics, our work sheds light on energy propagation in nonlinear materials with asymmetric crystalline structures and topological properties. We anticipate that breaking reciprocity will open avenues for energy absorption, conversion and harvesting, soft robotics, prosthetics and optomechanics.

  19. Structural optimization of free-form reciprocal structures

    DEFF Research Database (Denmark)

    Parigi, Dario

    2014-01-01

    This paper presents an optimization algorithm for the design of structurally efficient free-form reciprocal structures. Because of the geometric complexity of reciprocal structures, only a few structural studies have been carried out so far, and we have a limited knowledge of the relation between...... geometry and structural behaviour in reciprocal structures. This study takes advantage of the preceding work carried by the author on the Reciprocalizer, a software tool for the generation of reciprocal geometries. The Reciprocalizer has been included into a structural optimization algorithm...... for the generation of structurally efficient free-form reciprocal structures....

  20. Tax morale and reciprocity. A case study from Vietnam

    OpenAIRE

    Jahnke, Björn

    2015-01-01

    Understanding the effects of reciprocity on tax morale is crucial to explain tax compliance behavior. However, there is only little research about which sources of reciprocity affect tax morale most. Thus, this paper for the first time gauges the effects from two sources of reciprocity on tax morale in an empirical study. The first source, vertical reciprocity, measures how tax payers value their contributions to the government. The second source, horizontal reciprocity, examines the impact o...

  1. The neural correlates of reciprocity are sensitive to prior experience of reciprocity.

    Science.gov (United States)

    Cáceda, Ricardo; Prendes-Alvarez, Stefania; Hsu, Jung-Jiin; Tripathi, Shanti P; Kilts, Clint D; James, G Andrew

    2017-08-14

    Reciprocity is central to human relationships and is strongly influenced by multiple factors including the nature of social exchanges and their attendant emotional reactions. Despite recent advances in the field, the neural processes involved in this modulation of reciprocal behavior by ongoing social interaction are poorly understood. We hypothesized that activity within a discrete set of neural networks including a putative moral cognitive neural network is associated with reciprocity behavior. Nineteen healthy adults underwent functional magnetic resonance imaging scanning while playing the trustee role in the Trust Game. Personality traits and moral development were assessed. Independent component analysis was used to identify task-related functional brain networks and assess their relationship to behavior. The saliency network (insula and anterior cingulate) was positively correlated with reciprocity behavior. A consistent array of brain regions supports the engagement of emotional, self-referential and planning processes during social reciprocity behavior. Published by Elsevier B.V.

  2. Selection and optimization of pure and mixed working fluids for low grade heat utilization using organic Rankine cycles

    DEFF Research Database (Denmark)

    Andreasen, Jesper Graa; Larsen, Ulrik; Knudsen, Thomas

    2014-01-01

    We present a generic methodology for organic Rankine cycle optimization, where the working fluid is included as an optimization parameter, in order to maximize the net power output of the cycle. The method is applied on two optimization cases with hot fluid inlet temperatures at 120°C and 90°C. P...

  3. Thermodynamic analysis of an integrated gasification solid oxide fuel cell plant combined with an organic Rankine cycle

    DEFF Research Database (Denmark)

    Pierobon, Leonardo; Rokni, Masoud; Larsen, Ulrik

    2013-01-01

    into a fixed bed gasification plant to produce syngas which fuels the combined solid oxide fuel cells e organic Rankine cycle system to produce electricity. More than a hundred fluids are considered as possible alternative for the organic cycle using non-ideal equations of state (or state-of-the-art equations...

  4. Effect of prepulse laser wavelength on EUV emission from CO2 reheated laser-produced Sn plasma

    Science.gov (United States)

    Freeman, J. R.; Harilal, S. S.; Hassanein, A.; Rice, B.

    2013-03-01

    We investigated the role of prepulse laser wavelength on extreme-ultraviolet (EUV) emission and ionic debris generation. A 6 ns Nd:YAG laser operating at 266 nm was used to generate a pre-plasma that was then reheated by a 35 ns CO2 laser pumping pulse at 10.6 μm. At an ideal delay time, improvement in EUV conversion efficiency (CE) of up to 30 % was seen compared to the CE from the pumping pulse alone. It was also shown that the most probable Sn ion kinetic energies were reduced significantly with the use of a prepulse, however, ion fluence increased. These results were compared to those obtained using a 1064 nm prepulse.

  5. Multi-objective optimization of organic Rankine cycle power plants using pure and mixed working fluids

    DEFF Research Database (Denmark)

    Andreasen, Jesper Graa; Kærn, Martin Ryhl; Pierobon, Leonardo

    2015-01-01

    For zeotropic mixtures, the temperature varies during phase change, which is opposed to the isothermalphase change of pure fluids. The use of such mixtures as working fluids in organic Rankine cyclepower plants enables a minimization of the mean temperature difference of the heat exchangers whenthe...... mixturesare usually degraded compared to an ideal mixture heat transfer coefficient linearly interpolatedbetween the pure fluid values. This entails a need for larger and more expensive heat exchangers. Previousstudies primarily focus on the thermodynamic benefits of zeotropic mixtures by employing firstand...... second law analyses. In order to assess the feasibility of using zeotropic mixtures, it is, however,important to consider the additional costs of the heat exchangers. In this study, we aim at evaluatingthe economic feasibility of zeotropic mixtures compared to pure fluids. We carry out a multi...

  6. Working fluid selection for organic Rankine cycles - Impact of uncertainty of fluid properties

    DEFF Research Database (Denmark)

    Frutiger, Jerome; Andreasen, Jesper Graa; Liu, Wei

    2016-01-01

    This study presents a generic methodology to select working fluids for ORC (Organic Rankine Cycles)taking into account property uncertainties of the working fluids. A Monte Carlo procedure is described as a tool to propagate the influence of the input uncertainty of the fluid parameters on the ORC...... modeloutput, and provides the 95%-confidence interval of the net power output with respect to the fluid property uncertainties. The methodology has been applied to a molecular design problem for an ORCusing a low-temperature heat source and consisted of the following four parts: 1) formulation...... of processmodels and constraints 2) selection of property models, i.e. Penge Robinson equation of state 3)screening of 1965 possible working fluid candidates including identification of optimal process parametersbased on Monte Carlo sampling 4) propagating uncertainty of fluid parameters to the ORC netpower output...

  7. Parametric theoretical study of a two-stage solar organic Rankine cycle for RO desalination

    Energy Technology Data Exchange (ETDEWEB)

    Kosmadakis, G.; Manolakos, D.; Papadakis, G. [Department of Natural Resources and Agricultural Engineering, Agricultural University of Athens, 75 Iera Odos Street, 11855 Athens (Greece)

    2010-05-15

    The present work concerns the parametric study of an autonomous, two-stage solar organic Rankine cycle for RO desalination. The main goal of the current simulation is to estimate the efficiency, as well as to calculate the annual mechanical energy available for desalination in the considered cases, in order to evaluate the influence of various parameters on the performance of the system. The parametric study concerns the variation of different parameters, without changing actually the baseline case. The effect of the collectors' slope and the total number of evacuated tube collectors used, have been extensively examined. The total cost is also taken into consideration and is calculated for the different cases examined, along with the specific fresh water cost (EUR/m{sup 3}). (author)

  8. Comparative investigation of working fluids for an organic Rankine cycle with geothermal water

    Science.gov (United States)

    Liu, Yan-Na; Xiao, Song

    2015-06-01

    In this paper, the thermodynamic investigation on the use of geothermal water (130 °C as maximum) for power generation through a basic Rankine has been presented together with obtained main results. Six typical organic working fluids (i.e., R245fa, R141b, R290, R600, R152a, and 134a) were studied with modifying the input pressure and temperature to the turbine. The results show that there are no significant changes taking place in the efficiency for these working fluids with overheating the inlet fluid to the turbine, i.e., efficiency is a weak function of temperature. However, with the increasing of pressure ratio in the turbine, the efficiency rises more sharply. The technical viability is shown of implementing this type of process for recovering low temperature heat resource.

  9. Effectiveness of Operation of Organic Rankine Cycle Installation Applied in the Liquid Natural Gas Regasification Plant

    Science.gov (United States)

    Kaczmarek, R.; Stachel, A. A.

    2017-05-01

    An analysis of the operation of an Organic Rankine Cycle (ORC) installation heated by a low-temperature heat source is presented for the case where a condenser of a working fluid is cooled by a liquid of ultralow temperature. For this purpose, the process of regasification of liquid natural gas (LNG) is considered. In the process, the condensation heat of the working fluid in ORC is taken by the LNG evaporating subsequently (i.e., undergoing regasification). The paper presents the schematic of this installation and its application, as well as the results of calculations on the basis of the analysis in terms of the power and efficiency. In the analysis, organic fluids used in the ORC as working ones have been selected.

  10. Linear Active Disturbance Rejection Control of Waste Heat Recovery Systems with Organic Rankine Cycles

    Directory of Open Access Journals (Sweden)

    Fang Fang

    2012-12-01

    Full Text Available In this paper, a linear active disturbance rejection controller is proposed for a waste heat recovery system using an organic Rankine cycle process, whose model is obtained by applying the system identification technique. The disturbances imposed on the waste heat recovery system are estimated through an extended linear state observer and then compensated by a linear feedback control strategy. The proposed control strategy is applied to a 100 kW waste heat recovery system to handle the power demand variations of grid and process disturbances. The effectiveness of this controller is verified via a simulation study, and the results demonstrate that the proposed strategy can provide satisfactory tracking performance and disturbance rejection.

  11. Draft report: application of organic Rankine cycle heat recovery systems to diesel powered marine vessels

    Energy Technology Data Exchange (ETDEWEB)

    1977-07-15

    The analysis and results of an investigation of the application of organic Rankine cycle heat recovery systems to diesel-powered marine vessels are described. The program under which this study was conducted was sponsored jointly by the US Energy Research and Development Administration, the US Navy, and the US Maritime Administration. The overall objective of this study was to investigate diesel bottoming energy recovery systems, currently under development by three US concerns, to determine the potential for application to marine diesel propulsion and auxiliary systems. The study primarily focused on identifying the most promising vessel applications (considering vessel type, size, population density, operational duty cycle, etc.) so the relative economic and fuel conservation merits of energy recovery systems could be determined and assessed. Vessels in the current fleet and the projected 1985 fleet rated at 1000 BHP class and above were investigated.

  12. Thermal Stability of Hexamethyldisiloxane (MM for High-Temperature Organic Rankine Cycle (ORC

    Directory of Open Access Journals (Sweden)

    Markus Preißinger

    2016-03-01

    Full Text Available The design of efficient Organic Rankine Cycle (ORC units for the usage of industrial waste heat at high temperatures requires direct contact evaporators without intermediate thermal oil circuits. Therefore, the thermal stability of high-temperature working fluids gains importance. In this study, the thermal degradation of hexamethyldisiloxane (MM is investigated in an electrically heated tube. Qualitative results concerning remarks on degradation products as well as quantitative results like the annual degradation rate are presented. It is shown that MM is stable up to a temperature of 300 °C with annual degradation rates of less than 3.5%. Furthermore, the break of a silicon–carbon bond can be a main chemical reaction that influences the thermal degradation. Finally, it is discussed how the results may impact the future design of ORC units.

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

    Science.gov (United States)

    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.

  14. Organic Rankine cycle unit for waste heat recovery on ships (PilotORC)

    DEFF Research Database (Denmark)

    Haglind, Fredrik; Montagud, Maria E. Mondejar; Andreasen, Jesper Graa

    The project PilotORC was aimed at evaluating the technical and economic feasibility of the use of organic Rankine cycle (ORC) units to recover low-temperature waste heat sources (i.e. exhaust gases, scavenge air, engine cooling system, and lubricant oil system) on container vessels. The project...... included numerical simulations and experimental tests on a 125 kW demonstration ORC unit that utilizes the waste heat of the main engine cooling system on board one of Mærsk's container vessels. During the design of the demonstration ORC unit, different alternatives for the condenser were analyzed in order...... to minimize the size of the heat exchanger area. Later on the ORC unit was successfully installed on board, and it has been working uninterruptedly since, demonstrating the matureness of the ORC technology for maritime applications. During the onboard testing, additional measuring devices were installed...

  15. Recent research trends in organic Rankine cycle technology: A bibliometric approach

    DEFF Research Database (Denmark)

    Imran, Muhammad; Haglind, Fredrik; Asim, Muhammad

    2018-01-01

    Expanded. Different aspects of the publications were analyzed, such as publication type, major research areas, journals, citations, authorship pattern, affiliations as well as the keyword occurrence frequency. The impact factor, h-index and number of citations were used to investigate the strength...... of active countries, institutes, authors, and journals in the organic Rankine cycle technology field. From 2000 to 2016, there were 2120 articles published by 3443 authors from 997 research institutes scattered over 71 countries. The total number of citations and impact factor are 36,739 and 4597......, respectively, corresponding to 17 citations per paper and an impact factor of 2.168 per publication. The research articles originate primarily from China, the USA, and European countries. Results indicate that China, the United States, Italy, Greece, Belgium, Spain, Germany and the United Kingdom...

  16. Control system to a Rankine cycle with a Tesla turbine using arduino

    Energy Technology Data Exchange (ETDEWEB)

    Medeiros, Josenei G., E-mail: joseneigodoi@yahoo.com.br [Faculdade de Tecnologia Sao Francisco (FATESF), Jacarei, SP (Brazil); Guimaraes, Lamartine F.; Placco, Guilherme M., E-mail: guimarae@ieav.cta.br, E-mail: placco@ieav.cta.br [Instituto de Estudos Avancados (ENU/IEAv/DCTA), Sao Jose dos Campos, SP (Brazil). Departamento de Energia Nuclear

    2013-07-01

    The thermal Rankine cycle is a thermodynamic cycle which converts heat in energy. This cycle occurs in steady state, in other words the cycle is a closed loop circuit with continuous feedback, which guarantees the reuse process one energy transformed in the various stages of the cycle. This cycle is used to drive a turbine type TESLA designed for the system. The objective of this work is to create the control and automation of this cycle using an micro-controlled system with Arduino that will hold the collection of sensors and the system will act to maintain the balance of the cycle causing it to behave continuously and with less interference from human operation for maintenance. Data will be collected and further processed, where it will display all the sensors and the situation of the actuators involved. Using Arduino system ensures the stability and reliability with a low cost of implementation.

  17. Thermodynamic Analysis of an Integrated Solid Oxide Fuel Cell Cycle with a Rankine Cycle

    DEFF Research Database (Denmark)

    Rokni, Masoud

    2010-01-01

    Hybrid systems consisting of Solid Oxide Fuel Cells (SOFC) on the top of a Steam Turbine (ST) are investigated. The plants are fired by natural gas (NG). A desulfurization reactor removes the sulfur content in the fuel while a pre-reformer breaks down the heavier hydrocarbons. The pre-treated fuel...... enters then into the anode side of the SOFC. The remaining fuels after the SOFC stacks enter a burner for further burning. The off-gases are then used to produce steam for a Rankine cycle in a Heat Recovery Steam Generator (HRSG). Different system setups are suggested. Cyclic efficiencies up to 67......% are achieved which is considerably higher than the conventional Combined Cycles (CC). Both ASR (Adiabatic Steam Reformer) and CPO (Catalytic Partial Oxidation) fuel pre-reformer reactors are considered in this investigation....

  18. Computer modeling of a regenerative solar-assisted Rankine power cycle

    Science.gov (United States)

    Lansing, F. L.

    1977-01-01

    A detailed interpretation of the computer program that describes the performance of one of these cycles; namely, a regenerative Rankine power cycle is presented. Water is used as the working medium throughout the cycle. The solar energy collected at relatively low temperature level presents 75 to 80% of the total heat demand and provides mainly the latent heat of vaporization. Another energy source at high temperature level superheats the steam and supplements the solar energy share. A program summary and a numerical example showing the sequency of computations are included. The outcome from the model comprises line temperatures, component heat rates, specific steam consumption, percentage of solar energy contribution, and the overall thermal efficiency.

  19. Optimal design of compact organic Rankine cycle units for domestic solar applications

    Directory of Open Access Journals (Sweden)

    Barbazza Luca

    2014-01-01

    Full Text Available Organic Rankine cycle turbogenerators are a promising technology to transform the solar radiation harvested by solar collectors into electric power. The present work aims at sizing a small-scale organic Rankine cycle unit by tailoring its design for domestic solar applications. Stringent design criteria, i. e., compactness, high performance and safe operation, are targeted by adopting a multi-objective optimization approach modeled with the genetic algorithm. Design-point thermodynamic variables, e. g., evaporating pressure, the working fluid, minimum allowable temperature differences, and the equipment geometry, are the decision variables. Flat plate heat exchangers with herringbone corrugations are selected as heat transfer equipment for the preheater, the evaporator and the condenser. The results unveil the hyperbolic trend binding the net power output to the heat exchanger compactness. Findings also suggest that the evaporator and condenser minimum allowable temperature differences have the largest impact on the system volume and on the cycle performances. Among the fluids considered, the results indicate that R1234yf and R1234ze are the best working fluid candidates. Using flat plate solar collectors (hot water temperature equal to 75 °C, R1234yf is the optimal solution. The heat exchanger volume ranges between 6.0 and 23.0 dm3, whereas the thermal efficiency is around 4.5%. R1234ze is the best working fluid employing parabolic solar collectors (hot water temperature equal to 120 °C. In such case the thermal efficiency is around 6.9%, and the heat exchanger volume varies from 6.0 to 18.0 dm3.

  20. Analysis and optimization of the low-temperature solar organic Rankine cycle (ORC)

    Energy Technology Data Exchange (ETDEWEB)

    Delgado-Torres, Agustin M. [Dpto. Fisica Fundamental y Experimental, Electronica y Sistemas, Escuela Tecnica Superior de Ingenieria Civil e Industrial, Universidad de La Laguna (ULL), Avda, Astrofisico Francisco Sanchez s/n, 38206 La Laguna, Tenerife (Spain); Garcia-Rodriguez, Lourdes [Dpto. Ingenieria Energetica, Escuela Tecnica Superior de Ingenieros, Universidad de Sevilla, Camino de los Descubrimientos, s/n 41092 Sevilla (Spain)

    2010-12-15

    Solar thermal driven reverse osmosis desalination is a promising renewable energy-driven desalination technology. A joint use of the solar thermal powered organic Rankine cycle (ORC) and the desalination technology of less energy consumption, reverse osmosis (RO), makes this combination interesting in some scarce water resource scenarios. However, prior to any practical experience with any new process, a comprehensive and rigorous theoretical study must be done in order to assess the performance of the new technology or combination of existing technologies. The main objective of the present paper is the expansion of the theoretical analysis done by the authors in previous works to the case in which the thermal energy required by a solar ORC is supplied by means of stationary solar collectors. Twelve substances are considered as working fluids of the ORC and four different models of stationary solar collectors (flat plate collectors, compound parabolic collectors and evacuated tube collectors) are also taken into account. Operating conditions of the solar ORC that minimizes the aperture area needed per unit of mechanical power output of the solar cycle are determined for every working fluid and every solar collector. The former is done considering a direct vapour generation configuration of the solar cycle and also the configuration with water as heat transfer fluid flowing inside the solar collector. This work is part of the theoretical analysis of the solar thermal driven seawater and brackish water reverse osmosis desalination technology. Nevertheless, the supplied information can be also used for the assessment of different applications of the solar ORC. In that case, results presented in this paper can be useful in techno-economic analysis, selection of working fluids of the Rankine cycle, sizing of systems and assessment of solar power cycle configuration. (author)

  1. Modelling fluid flow in a reciprocating compressor

    Directory of Open Access Journals (Sweden)

    Tuhovcak Jan

    2015-01-01

    Full Text Available Efficiency of reciprocating compressor is strongly dependent on the valves characteristics, which affects the flow through the suction and discharge line. Understanding the phenomenon inside the compressor is necessary step in development process. Commercial CFD tools offer wide capabilities to simulate the flow inside the reciprocating compressor, however they are too complicated in terms of computational time and mesh creation. Several parameters describing compressor could be therefore examined without the CFD analysis, such is valve characteristic, flow through the cycle and heat transfer. The aim of this paper is to show a numerical tool for reciprocating compressor based on the energy balance through the cycle, which provides valve characteristics, flow through the cycle and heat losses from the cylinder. Spring-damping-mass model was used for the valve description. Boundary conditions were extracted from the performance test of 4-cylinder semihermetic compressor and numerical tool validation was performed with indicated p-V diagram comparison.

  2. Reciprocation and altruism in social cooperation.

    Science.gov (United States)

    Safin, Vasiliy; Arfer, Kodi B; Rachlin, Howard

    2015-07-01

    Altruistic behavior benefits other individuals at a cost to oneself. The purpose of the present experiment was to study altruistic behavior by players (P) in 2-person iterated prisoner's dilemma games in which reciprocation by the other player (OP) was impossible, and this impossibility was clear to P. Altruism by P could not therefore be attributed to expectation of reciprocation. The cost to P of altruistic behavior was constant throughout the study, but the benefit to OP from P's cooperation differed between groups and conditions. Rate of cooperation was higher when benefit to OP was higher. Thus altruism (not attributable to expectation of reciprocation) can be a significant factor in interpersonal relationships as studied in iterated prisoner's dilemma games, and needs to be taken into account in their analysis. Copyright © 2015 Elsevier B.V. All rights reserved.

  3. Exergy analysis of micro-organic Rankine power cycles for a small scale solar driven reverse osmosis desalination system

    Energy Technology Data Exchange (ETDEWEB)

    Tchanche, B.F.; Lambrinos, Gr.; Frangoudakis, A.; Papadakis, G. [Department of Natural Resources and Agricultural Engineering, Agricultural University of Athens, 75 Iera Odos Street, 11855 Athens (Greece)

    2010-04-15

    Exergy analysis of micro-organic Rankine heat engines is performed to identify the most suitable engine for driving a small scale reverse osmosis desalination system. Three modified engines derived from simple Rankine engine using regeneration (incorporation of regenerator or feedliquid heaters) are analyzed through a novel approach, called exergy-topological method based on the combination of exergy flow graphs, exergy loss graphs, and thermoeconomic graphs. For the investigations, three working fluids are considered: R134a, R245fa and R600. The incorporated devices produce different results with different fluids. Exergy destruction throughout the systems operating with R134a was quantified and illustrated using exergy diagrams. The sites with greater exergy destruction include turbine, evaporator and feedliquid heaters. The most critical components include evaporator, turbine and mixing units. A regenerative heat exchanger has positive effects only when the engine operates with dry fluids; feedliquid heaters improve the degree of thermodynamic perfection of the system but lead to loss in exergetic efficiency. Although, different modifications produce better energy conversion and less exergy destroyed, the improvements are not significant enough and subsequent modifications of the simple Rankine engine cannot be considered as economically profitable for heat source temperature below 100 C. As illustration, a regenerator increases the system's energy efficiency by 7%, the degree of thermodynamic perfection by 3.5% while the exergetic efficiency is unchanged in comparison with the simple Rankine cycle, with R600 as working fluid. The impacts of heat source temperature and pinch point temperature difference on engine's performance are also examined. Finally, results demonstrate that energy analysis combined with the mathematical graph theory is a powerful tool in performance assessments of Rankine based power systems and permits meaningful comparison of

  4. Influence of the reheat temperature on the efficiency of the wet-steam turbines of thermal power plants that operate under variable conditions

    Science.gov (United States)

    Tarelin, A. A.

    2017-04-01

    A brief analysis of the existing methods for controlling the operating conditions of the turbine units that operate at variable loads is presented. In practice, the outdated rule of operation is most frequently used that states that the higher the parameters of the live and reheat steam and the lower the condenser pressure are, the higher is the efficiency of the turbine unit. However, in the technical literature, there is sufficiently substantiated evidence that this approach is not always correct, especially under low loads. This applies to both the regulation of the initial and final pressure and reheat temperature t r. In the article, particular stress is laid on the controllable parameter t r, the effect of which in the operational practices, according to the results of the analysis, is underestimated. The causes are considered that constrain more effective use of reheat temperature t r as a process variable. The results of field trials to investigate the influence of t r on the efficiency of turbine units of various capacities, viz., of 210, 250, 300, and 325 MW, during operation at varying loads are presented. It is shown that a decrease in t r to an optimal value of 10-30°C, depending on the load and the condenser pressure, increases the thermal efficiency by 1-2%. The following general pattern has been set: the lower the load, the lower the optimal reheat temperature. The main causes and factors that result in more efficient use of the heat phase transition in the steam path of the low-pressure cylinder and increased efficiency of the unit under rational choice of the reheat temperature are studied.

  5. Enhanced additive manufacturing with a reciprocating platen

    Energy Technology Data Exchange (ETDEWEB)

    Lind, Randall F.; Blue, Craig A.; Love, Lonnie J.; Post, Brian K.; Lloyd, Peter D.

    2018-02-06

    An additive manufacturing extrusion head that includes a heated nozzle for accepting a feedstock and extruding the feedstock onto a substrate at a deposition plane, the nozzle having a longitudinal extrusion axis. A reciprocating platen surrounds the nozzle, the platen operable to reciprocate along the extrusion axis at or above the deposition plane as the nozzle extrudes feedstock onto the substrate; and wherein the platen flattens the extruded feedstock such that it does not protrude above the deposition plane as the extrusion head traverses over the substrate.

  6. Human-animal amity and reciprocity

    NARCIS (Netherlands)

    Wissenburg, M.L.J.

    2014-01-01

    Animals are now widely accepted as subjects of justice: not equal but deserving equal consideration; not free but deserving liberties (that is, selfconstraining human duties). But liberty and equality are not all there is to a flourishing society – how about amity and reciprocity? Isn’t a minimal

  7. Reciprocity of support in coatis (Nasua nasua).

    Science.gov (United States)

    Romero, Teresa; Aureli, Filippo

    2008-02-01

    Primate sociality has received much attention and its complexity has been viewed as a driving force for the evolution of cognitive abilities. Improved analytic techniques have allowed primate researchers to reveal intricate social networks based on the exchange of cooperative acts and services. Although nonprimates are known to show similar behavior (e.g., cooperative hunting, food sharing, coalitions) there seems a consensus that social life is less complex than in primates. Here the authors present the first group-level analysis of reciprocity of social interactions in a social carnivore, the ring-tailed coati (Nasua nasua). The authors found that support in aggressive conflicts is a common feature in coatis and that this behavior is reciprocally exchanged in a manner seemingly as complex as in primates. Given that reciprocity correlations persisted after controlling for the effect of spatial association and subunit membership, some level of scorekeeping may be involved. Further studies will be needed to confirm our findings and understand the mechanisms underlying such reciprocity, but our results contribute to the body of work that has begun to challenge primate supremacy in social complexity and cognition. (c) 2008 APA.

  8. Reciprocity and Junior High School Friendships.

    Science.gov (United States)

    Ayers, Marla; Clark, M. L.

    Data collected from 136 7th and 8th graders were analyzed to assess the relationship between reciprocity (mutual and non-mutual selection of friends), friendship similarity (in the areas of sex, race, physical attractiveness, interpersonal attitudes, intelligence, and friendship satisfaction and commitment) and friendship proximity both in and out…

  9. Reciprocity, Materialism and Welfare: An Evolutionary Model

    DEFF Research Database (Denmark)

    Poulsen, Anders

    2001-01-01

    We analyze preference evolution in a simple bargaining situation. Preferences for reciprocity, who sustain a conflict-free outcome, may be viable if players have enough information about the opponent's preferences. However, depending on the initial starting point preference evolution can in general...

  10. Integral inequalities for self-reciprocal polynomials

    Indian Academy of Sciences (India)

    Annual Meetings · Mid Year Meetings · Discussion Meetings · Public Lectures · Lecture Workshops · Refresher Courses · Symposia · Live Streaming. Home; Journals; Proceedings – Mathematical Sciences; Volume 120; Issue 2. Integral Inequalities for Self-Reciprocal Polynomials. Horst Alzer. Volume 120 Issue 2 April 2010 ...

  11. Cooperation under indirect reciprocity and imitative trust.

    Directory of Open Access Journals (Sweden)

    Serguei Saavedra

    Full Text Available Indirect reciprocity, a key concept in behavioral experiments and evolutionary game theory, provides a mechanism that allows reciprocal altruism to emerge in a population of self-regarding individuals even when repeated interactions between pairs of actors are unlikely. Recent empirical evidence show that humans typically follow complex assessment strategies involving both reciprocity and social imitation when making cooperative decisions. However, currently, we have no systematic understanding of how imitation, a mechanism that may also generate negative effects via a process of cumulative advantage, affects cooperation when repeated interactions are unlikely or information about a recipient's reputation is unavailable. Here we extend existing evolutionary models, which use an image score for reputation to track how individuals cooperate by contributing resources, by introducing a new imitative-trust score, which tracks whether actors have been the recipients of cooperation in the past. We show that imitative trust can co-exist with indirect reciprocity mechanisms up to a threshold and then cooperation reverses -revealing the elusive nature of cooperation. Moreover, we find that when information about a recipient's reputation is limited, trusting the action of third parties towards her (i.e. imitating does favor a higher collective cooperation compared to random-trusting and share-alike mechanisms. We believe these results shed new light on the factors favoring social imitation as an adaptive mechanism in populations of cooperating social actors.

  12. Generalized reciprocal method applied in processing seismic ...

    African Journals Online (AJOL)

    A geophysical investigation was carried out at Shika, near Zaria, using seismic refraction method; with the aim of analyzing the data obtained using the generalized reciprocal method (GRM). The technique is for delineating undulating refractors at any depth from in-line seismic refraction data consisting of forward and ...

  13. Preliminary Design and Simulation of a Turbo Expander for Small Rated Power Organic Rankine Cycle (ORC

    Directory of Open Access Journals (Sweden)

    Roberto Capata

    2014-11-01

    Full Text Available Nowadays, the Organic Rankine Cycle (ORC system, which operates with organic fluids, is one of the leading technologies for “waste energy recovery”. It works as a conventional Rankine Cycle but, as mentioned, instead of steam/water, an organic fluid is used. This change allows it to convert low temperature heat into electric energy where required. Large numbers of studies have been carried out to identify the most suitable fluids, system parameters and the various configurations. In the present market, most ORC systems are designed and manufactured for the recovery of thermal energy from various sources operating at “large power rating” (exhaust gas turbines, internal combustion engines, geothermal sources, large melting furnaces, biomass, solar, etc.; from which it is possible to produce a large amount of electric energy (30 kW ÷ 300 kW. Such applications for small nominal power sources, as well as the exhaust gases of internal combustion engines (car sedan or town, ships, etc. or small heat exchangers, are very limited. The few systems that have been designed and built for small scale applications, have, on the other hand, different types of expander (screw, scroll, etc.. These devices are not adapted for placement in small and restricted places like the interior of a conventional car. The aim of this work is to perform the preliminary design of a turbo-expander that meets diverse system requirements such as low pressure, small size and low mass flow rates. The expander must be adaptable to a small ORC system utilizing gas of a diesel engine or small gas turbine as thermal source to produce 2–10 kW of electricity. The temperature and pressure of the exhaust gases, in this case study (400–600 °C and a pressure of 2 bar, imposes a limit on the use of an organic fluid and on the net power that can be produced. In addition to water, fluids such as CO2, R134a and R245fa have been considered. Once the operating fluids has been chosen

  14. Analysis of a rotating spool expander for Organic Rankine Cycle applications

    Science.gov (United States)

    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

  15. Exergy and economic analysis of organic rankine cycle hybrid system utilizing biogas and solar energy in rural area of China

    DEFF Research Database (Denmark)

    Zhao, Chunhua; Zheng, Siyu; Zhang, Ji

    2017-01-01

    Due to the existing huge biogas resource in the rural area of China, biogas is widely used for production and living. Cogeneration system provides an opportunity to realize the balanced utilization of the renewable energy such as biogas and solar energy. This paper presented a numerical...... investigation of a hybrid energy-driven organic Rankine cycle (ORC) cogeneration system, involving a solar organic Rankine cycle and a biogas boiler. The biogas boiler with a module of solar Parabolic-Trough Collectors (PTC) is employed to provide heat source to the ORC via two distinct intermediate pressurized...... circuits. The cogeneration supplied the power to the air-condition in summer condition and hot water, which is heated in the condenser, in winter condition. The system performance under the subcritical pressures has been assessed according to the energy-exergy and economic analysis with the organic working...

  16. Radial turbine expander design for organic rankine cycle, waste heat recovery in high efficiency, off-highway vehicles

    OpenAIRE

    Alshammari, F.; Karvountzis-Kontakiotis, A; Pesiridis, A

    2016-01-01

    Although state-of-the-art, heavy duty diesel engines of today can reach peak thermal efficiencies of approximately 45%, still most of the fuel energy is transformed into wasted heat in the internal combustion process. Recovering this wasted energy could increase the overall thermal efficiency of the engine as well as reduce the exhaust gas emissions. Compared to other Waste Heat Recovery (WHR) technologies, Organic Rankine Cycle (ORC) systems are regarded favourably due to their relative simp...

  17. Part-Load Performance of a Wet Indirectly Fired Gas Turbine Integrated with an Organic Rankine Cycle Turbogenerator

    OpenAIRE

    Leonardo Pierobon; Tuong-Van Nguyen; Andrea Mazzucco; Ulrik Larsen; Fredrik Haglind

    2014-01-01

    Over the last years, much attention has been paid to the development of efficient and low-cost power systems for biomass-to-electricity conversion. This paper aims at investigating the design- and part-load performance of an innovative plant based on a wet indirectly fired gas turbine (WIFGT) fueled by woodchips and an organic Rankine cycle (ORC) turbogenerator. An exergy analysis is performed to identify the sources of inefficiencies, the optimal design variables, and the most suitable worki...

  18. Modelling of organic Rankine cycle power systems in off-design conditions: an experimentally-validated comparative study

    OpenAIRE

    Dickes, Rémi; Dumont, Olivier; Daccord, Rémi; Quoilin, Sylvain; Lemort, Vincent

    2017-01-01

    Because of environmental issues and the depletion of fossil fuels, the world energy sector is undergoing many changes toward increased sustainability. Among the many fields of research and development, power generation from low-grade heat sources is gaining interest and the organic Rankine cycle (ORC) is seen as one of the most promising technologies for such applications. In this paper, it is proposed to perform an experimentally-validated comparison of different modelling methods for the of...

  19. Bayesian Zero-Failure (BAZE) reliability demonstration testing procedure and its application to a Rankine dynamic radioisotope power conversion system

    Energy Technology Data Exchange (ETDEWEB)

    Martz, H.F. Jr.; Waller, R.A.

    1976-07-01

    A Bayesian Zero-Failure (BAZE) reliability demonstration testing procedure is developed. The procedure may be used to verify component failure rates associated with both real-time dependent and cycle-dependent chance failure mechanisms. A constant falure-rate model with a gamma prior distribution is assumed. The procedure is used to obtain sample test plans for components of a proposed Rankine power conversion system.

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

    Science.gov (United States)

    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.

  1. Performance of Siloxane Mixtures in a High-Temperature Organic Rankine Cycle Considering the Heat Transfer Characteristics during Evaporation

    OpenAIRE

    Theresa Weith; Florian Heberle; Markus Preißinger; Dieter Brüggemann

    2014-01-01

    The application of the Organic Rankine Cycle to high temperature heat sources is investigated on the case study of waste heat recovery from a selected biogas plant. Two different modes of operation are distinguished: pure electric power and combined heat and power generation. The siloxanes hexamethyldisiloxane (MM) and octamethyltrisiloxane (MDM) are chosen as working fluids. Moreover, the effect of using mixtures of these components is analysed. Regarding pure electricity generation, process...

  2. Management Research on Reciprocity: A Review of the Literature

    Directory of Open Access Journals (Sweden)

    Markus Göbel

    2013-05-01

    Full Text Available Although reciprocity is fundamental to all social orders, management research offers few reviews of the concept’s theoretical origins and current applications. To help bridge this gap, we elucidate the dominant understandings of reciprocity, ask which areas of research emerge from them, and explore how they interconnect. Our bibliometric methodology detects four clusters of management research on reciprocity. Across these clusters, authors subscribe mainly to substantialist ontology, marginalize morally oriented motives consistent with relational ontology, and largely assume that benefit-oriented motives underlie reciprocity. We outline the advantages of a moral-oriented relationalist concept of reciprocity and discuss potential areas for its development in management research.

  3. Structural Changes in Cooked Rice Treated with Cooling-Reheating Process and Coconut Milk Addition as Observed With FT-IR and 13C NMR

    Directory of Open Access Journals (Sweden)

    Nuri Arum Anugrahati

    2017-03-01

    Full Text Available The molecular structural changes of food could be observed by the technique of FT-IR and 13C NMR spectroscopy. This research was aimed to study the structural changes in cooked rice treated with cooling-reheating process and coconut milk addition using FT-IR and 13C NMR. It was found that the cooling-reheating process and addition of coconut milk cause several structural changes of cooked rice. The IR analysis showed the bands at 3,400, 2,900, 1,018 and 856 cm-1 changed due to the retrogradation during cooling process. The spectrum of 13C NMR showed the change of peaks at 100.28 and 100.10 ppm. These changes may be related to the addition of coconut milk during rice cooking.

  4. Microstructural characteristics and gastro-small intestinal digestion in vitro of potato starch: Effects of refrigerated storage and reheating in microwave.

    Science.gov (United States)

    Colussi, Rosana; Singh, Jaspreet; Kaur, Lovedeep; Zavareze, Elessandra da Rosa; Dias, Alvaro Renato Guerra; Stewart, Robert B; Singh, Harjinder

    2017-07-01

    The objective of our study was to evaluate paste clarity, retrogradation (syneresis %), thermal characteristics and kinetics of glucose release during in vitro gastro-small intestinal digestion of freshly cooked and refrigerated potato starch. Freshly cooked starch pastes had a paste clarity of 71%, which decreased to 35.4% whereas syneresis (%) increased after 7days of refrigerated storage. The X-ray and thermal characteristics of native, retrograded and microwave reheated starch samples differed significantly from each other. For the freshly cooked starch pastes, ∼88% starch hydrolysis was observed at the end (150min) of digestion under simulated gastro-small intestinal conditions that decreased to ∼70% for the 7day stored pastes. The hydrolysis (%) of refrigerated pastes increased to 86% and 92% after one and two cycles of microwave reheating, respectively. These results contribute to the understanding of starch retrogradation in relation to starch digestion. Copyright © 2017 Elsevier Ltd. All rights reserved.

  5. Formation of reciprocal appreciation patterns in small groups: an agent-based model

    OpenAIRE

    Koponen, Ismo T; Nousiainen, Maija

    2016-01-01

    Abstract Purpose In small cooperative and collaborative groups, patterns of interaction, discourse and dialogue are often strongly bidirectional; ties are reciprocal and reciprocated. This reciprocation of ties leads to the formation of interaction patterns that are reciprocated dyads (two individuals connected reciprocally) and triads (three individuals connected reciprocally). In this study, we use an agent-based model to explore how s...

  6. Organic Rankine cycle – review and research directions in engine applications

    Directory of Open Access Journals (Sweden)

    Panesar Angad

    2017-01-01

    Full Text Available 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.

  7. Exergetic Analysis of an Integrated Tri-Generation Organic Rankine Cycle

    Directory of Open Access Journals (Sweden)

    Ratha Z. Mathkor

    2015-08-01

    Full Text Available This paper reports on a study of the modelling, validation and analysis of an integrated 1 MW (electrical output tri-generation system energized by solar energy. The impact of local climatic conditions in the Mediterranean region on the system performance was considered. The output of the system that comprised a parabolic trough collector (PTC, an organic Rankine cycle (ORC, single-effect desalination (SED, and single effect LiBr-H2O absorption chiller (ACH was electrical power, distilled water, and refrigerant load. The electrical power was produced by the ORC which used cyclopentane as working fluid and Therminol VP-1 was specified as the heat transfer oil (HTO in the collectors with thermal storage. The absorption chiller and the desalination unit were utilize the waste heat exiting from the steam turbine in the ORC to provide the necessary cooling energy and drinking water respectively. The modelling, which includes an exergetic analysis, focuses on the performance of the solar tri-generation system. The simulation results of the tri-generation system and its subsystems were produced using IPSEpro software and were validated against experimental data which showed good agreement. The tri-generation system was able to produce about 194 Ton of refrigeration, and 234 t/day distilled water.

  8. Organic Rankine kilowatt isotope power system. First annual summary report, August 1, 1975--August 1, 1976

    Energy Technology Data Exchange (ETDEWEB)

    1976-01-01

    Sundstrand Energy Systems is developing a Kilowatt Isotope Power System (KIPS) directed toward satisfying the higher power requirements of satellites of the 1980's. The KIPS is a plutonium oxide fueled organic Rankine cycle turbine power system which will provide design output power in the range of 500 to 2000 W(e) with a minimum of system changes. Research progress is reported on Phase I comprising: (1) flight system conceptual design and ground demonstration; (2) flight system design and ground qualification; and (3) flight system production, acceptance testing and delivery. The principal objectives of Phase I are to: (1) conceptually design the flight system, (2) based on the flight system concept, design and build the ground demonstration system (GDS), (3) conduct performance and endurance testing using electric heaters to simulate the radioisotope heat source, (4) identify and initiate long lead development efforts required to achieve the initial flight qualification hardware availability date of April 1981, and (5) finalize the flight concept design and prepare the program plan for the Phase II effort.

  9. Energy analysis of a trigeneration plant based on solid oxide fuel cell and organic Rankine cycle

    Energy Technology Data Exchange (ETDEWEB)

    Al-Sulaiman, Fahad A. [Mechanical and Aerospace Engineering Department, Carleton University, 1125 Colonel By Drive, Ottawa, Ontario (Canada); Dincer, Ibrahim [Faculty of Engineering and Applied Science, University of Ontario Institute of Technology, 2000 Simcoe Street North, Oshawa, Ontario (Canada); Hamdullahpur, Feridun [Mechanical and Mechatronics Engineering Department, University of Waterloo, 200 University Avenue West, Waterloo, Ontario (Canada)

    2010-05-15

    In this study, energy analysis of a trigeneration plant based on solid oxide fuel cell (SOFC) and organic Rankine cycle (ORC) is conducted. The physical and thermodynamic elements of the plant include an SOFC, an ORC, a heat exchanger for the heating process and a single-effect absorption chiller for cooling. The results obtained from this study show that there is at least a 22% gain in efficiency using the trigeneration plant compared with the power cycle (SOFC and ORC). The study also shows that the maximum efficiency of the trigeneration plant is 74%, heating cogeneration is 71%, cooling cogeneration is 57% and net electricity is 46%. Furthermore, it is found that the highest net power output that can be provided by the trigeneration plant considered in this study is 540 kW and, the highest SOFC-AC power is 520 kW. The study reveals that the inlet pressure of the turbine has an insignificant effect on the efficiency. The study also examines the effect of both the SOFC current density and the SOFC inlet flow temperature on the cell voltage and voltage loss. (author)

  10. Numerical computation of motions and structural loads for large containership using 3D Rankine panel method

    Science.gov (United States)

    Kim, Jung-Hyun; Kim, Yonghwan

    2017-12-01

    In this paper, we present the results of our numerical seakeeping analyses of a 6750-TEU containership, which were subjected to the benchmark test of the 2nd ITTC-ISSC Joint Workshop held in 2014. We performed the seakeeping analyses using three different methods based on a 3D Rankine panel method, including 1) a rigid-body solver, 2) a flexible-body solver using a beam model, and 3) a flexible-body solver using the eigenvectors of a 3D Finite Element Model (FEM). The flexible-body solvers adopt a fully coupled approach between the fluid and structure. We consider the nonlinear Froude-Krylov and restoring forces using a weakly nonlinear approach. In addition, we calculate the slamming loads on the bow flare and stern using a 2D generalized Wagner model. We compare the numerical and experimental results in terms of the linear response, the time series of the nonlinear response, and the longitudinal distribution of the sagging and hogging moments. The flexible-body solvers show good agreement with the experimental model with respect to both the linear and nonlinear results, including the high-frequency oscillations due to springing and whipping vibrations. The rigid-body solver gives similar results except for the springing and whipping.

  11. Performance analysis of an organic Rankine cycle with internal heat exchanger having zeotropic working fluid

    Directory of Open Access Journals (Sweden)

    Thoranis Deethayat

    2015-09-01

    Full Text Available In this study, performance of a 50 kW organic Rankine cycle (ORC with internal heat exchanger (IHE having R245fa/R152a zeotropic refrigerant with various compositions was investigated. The IHE could reduce heat rate at the ORC evaporator and better cycle efficiency could be obtained. The zeotropic mixture could reduce the irreversibilities during the heat exchanges at the ORC evaporator and the ORC condenser due to its gliding temperature; thus the cycle working temperatures came closer to the temperatures of the heat source and the heat sink. In this paper, effects of evaporating temperature, mass fraction of R152a and effectiveness of internal heat exchanger on the ORC performances for the first law and the second law of thermodynamics were considered. The simulated results showed that reduction of R245fa composition could reduce the irreversibilities at the evaporator and the condenser. The suitable composition of R245fa was around 80% mass fraction and below this the irreversibilities were nearly steady. Higher evaporating temperature and higher internal heat exchanger effectiveness also increased the first law and second law efficiencies. A set of correlations to estimate the first and the second law efficiencies with the mass fraction of R245fa, the internal heat exchanger effectiveness and the evaporating temperature were also developed.

  12. Organic Rankine Cycle Analysis: Finding the Best Way to Utilize Waste Heat

    Directory of Open Access Journals (Sweden)

    Nadim Chakroun

    2012-01-01

    Full Text Available An Organic Rankine Cycle (ORC is a type of power cyclethat uses organic substances such as hydrocarbons orrefrigerants as the working fluid. ORC technology is usedto generate electricity in waste heat recovery applications,because the available heat is not at a high enoughtemperature to operate with other types of cycles. Theoptimum amount of working fluid required for the cycle(i.e., optimum charge level was investigated. Three chargelevels (13, 15, and 18 lbm were tested, and their effect onefficiency and performance of the system was analyzed.The heat source for the fluid was waste steam from thePurdue Power Plant, which had an average temperatureof 120oC. Regular city tap water at a temperature of 15oCwas used as the heat sink. For each charge level, multipletests were performed by measuring the temperaturesand pressures at all state points in the cycle, in order tounderstand any overarching patterns within the data.An important parameter that was analyzed is the 2nd lawefficiency. This efficiency is a measure of the effectivenessof the energy utilization compared to that of an idealcase. The peak efficiency increased from 24% to 27% asthe charge in the system decreased. Therefore, movingforward, this research suggests that a lower charge levelin the system will increase efficiency. However, testingbelow 13 lbm might cause mechanical complications inthe equipment as there may not be enough fluid to flowaround; thus, a compromise had to be made.

  13. Dynamic Simulation of an Organic Rankine Cycle—Detailed Model of a Kettle Boiler

    Directory of Open Access Journals (Sweden)

    Roberto Pili

    2017-04-01

    Full Text Available Organic Rankine Cycles (ORCs are nowadays a valuable technology to produce electricity from low and medium temperature heat sources, e.g., in geothermal, biomass and waste heat recovery applications. Dynamic simulations can help improve the flexibility and operation of such plants, and guarantee a better economic performance. In this work, a dynamic model for a multi-pass kettle evaporator of a geothermal ORC power plant has been developed and its dynamics have been validated against measured data. The model combines the finite volume approach on the tube side and a two-volume cavity on the shell side. To validate the dynamic model, a positive and a negative step function in heat source flow rate is applied. The simulation model performed well in both cases. The liquid level appeared the most challenging quantity to simulate. A better agreement in temperature was achieved by increasing the volume flow rate of the geothermal brine by 2% over the entire simulation. Measurement errors, discrepancies in working fluid and thermal brine properties and uncertainties in heat transfer correlations can account for this. In the future, the entire geothermal power plant will be simulated, and suggestions to improve its dynamics and control by means of simulations will be provided.

  14. Simulation of a passive house coupled with a heat pump/organic Rankine cycle reversible unit

    DEFF Research Database (Denmark)

    Dumont, Olivier; Carmo, Carolina; Randaxhe, François

    2014-01-01

    This paper presents a dynamic model of a passive house located in Denmark with a large solar absorber, a horizontal ground heat exchanger coupled with a HP/ORC unit. The HP/ORC reversible unit is a module able to work as an Organic Rankine Cycle (ORC) or as a heat pump (HP). There are 3 possible...... modes that need to be chosen optimally depending on the weather conditions, the heat demand and the temperature level of the storage. The ORC mode is activated, as long as the heat demand of the house is covered by the storage to produce electricity based upon the heat generated by the solar roof...... of the year in the Modelica language. A peak of 3.28 kW of power is reached in ORC mode with a heat input of 59.5 kW from the solar roof (23.9 kWh are produced during a typical summer day). In a representative winter day, 17.28 kWh are consumed by the heat pump with a daily average COP of 4.1. Conclusions...

  15. Comparison of different iterative schemes for ISPH based on Rankine source solution

    Directory of Open Access Journals (Sweden)

    Xing Zheng

    2017-07-01

    Full Text Available Smoothed Particle Hydrodynamics (SPH method has a good adaptability for the simulation of free surface flow problems. There are two forms of SPH. One is weak compressible SPH and the other one is incompressible SPH (ISPH. Compared with the former one, ISPH method performs better in many cases. ISPH based on Rankine source solution can perform better than traditional ISPH, as it can use larger stepping length by avoiding the second order derivative in pressure Poisson equation. However, ISPH_R method needs to solve the sparse linear matrix for pressure Poisson equation, which is one of the most expensive parts during one time stepping calculation. Iterative methods are normally used for solving Poisson equation with large particle numbers. However, there are many iterative methods available and the question for using which one is still open. In this paper, three iterative methods, CGS, Bi-CGstab and GMRES are compared, which are suitable and typical for large unsymmetrical sparse matrix solutions. According to the numerical tests on different cases, still water test, dam breaking, violent tank sloshing, solitary wave slamming, the GMRES method is more efficient than CGS and Bi-CGstab for ISPH method.

  16. Organic Rankine-cycle power systems working fluids study: Topical report No. 2, Toluene

    Energy Technology Data Exchange (ETDEWEB)

    Cole, R.L.; Demirgian, J.C.; Allen, J.W.

    1987-02-01

    The US Department of Energy initiated an investigation at Argonne National Laboratory in 1982 to experimentally determine the thermal stability limits and degradation rates of toluene as a function of maximum cycle temperature. Following the design and construction of a dynamic test loop capable of closely simulating the thermodynamic conditions of typical organic Rankine-cycle (ORC) power systems, four test runs, totaling about 3900 h of test time and covering a temperature range of 600-677(degree)F, were completed. Both liquid and noncondensable-vapor (gaseous) samples were drawn periodically and analyzed using capillary-column gas chromatography, gas chromatography/mass spectrometry, and mass spectrometry. A computer program that can predict degradation in an ORC engine was developed. Experimental results indicate that, if oxygen can be excluded from the system, toluene is a stable fluid up to the maximum test temperature; the charge of toluene could be used for several years before replacement became necessary. (Additional data provided by Sundstrand Corp. from tests sponsored by the National Aeronautics and Space Administration indicate that toluene may be used at temperatures up to 750(degree)F.) Degradation products are benign; the main liquid degradation products are bibenzyls, and the main gaseous degradation products are hydrogen and methane. A cold trap to remove gaseous degradation products from the condenser is necessary for extended operation. 21 figs., 22 tabs.

  17. Corrections to the Rankine-Hugoniot conditions for curved shock waves

    Science.gov (United States)

    Lancellotti, Carlo; Yue, Yubei

    2014-12-01

    Several years ago, Carlo Cercignani and one of the authors in a paper (C. Cercignani, 2991) performed a mathe-matical analysis of the corrections to the Rankine-Hugoniot conditions due to the curvature of a shock front, using singular perturbation methods in order to "connect" the solutions to the the Boltzmann equation inside and outside the shock layer. It turned out that these corrections can be obtained at leading order by integrating appropriately the Boltzmann shock profile for a planar (one-dimensional in space) shock wave. However, they are entirely due to the spatially asymmetry of the shock, and they vanish if the shock is described using a simple bi-modal ansatz like the well-know Mott-Smith model. In the present work we extend and simplify the previous results, and then use a recently-developed deterministic (spectral) Boltzmann solver for a gas of hard-spheres in order to obtain accurate numerical values for the curvature corrections.

  18. Thermal analysis of a Phase Change Material for a Solar Organic Rankine Cycle

    Science.gov (United States)

    Iasiello, M.; Braimakis, K.; Andreozzi, A.; Karellas, S.

    2017-11-01

    Organic Rankine Cycle (ORC) is a promising technology for low temperature power generation, for example for the utilization of medium temperature solar energy. Since heat generated from solar source is variable throughout the day, the implementation of Thermal Energy Storage (TES) systems to guarantee the continuous operation of solar ORCs is a critical task, and Phase Change Materials (PCM) rely on latent heat to store large amounts of energy. In the present study, a thermal analysis of a PCM for a solar ORC is carried out. Three different types of PCMs are analyzed. The energy equation for the PCM is modeled by using the heat capacity method, and it is solved by employing a 1Dexplicit finite difference scheme. The solar source is modeled with a time-variable temperature boundary condition, with experimental data taken from the literature for two different solar collectors. Results are presented in terms of temperature profiles and stored energy. It has been shown that the stored energy depends on the heat source temperature, on the employed PCM and on the boundary conditions. It has been demonstrated that the use of a metal foam can drastically enhance the stored energy due to the higher overall thermal conductivity.

  19. The simulation of organic rankine cycle power plant with n-pentane working fluid

    Science.gov (United States)

    Nurhilal, Otong; Mulyana, Cukup; Suhendi, Nendi; Sapdiana, Didi

    2016-02-01

    In the steam power plant in Indonesia the dry steam from separator directly used to drive the turbin. Meanwhile, brine from the separator with low grade temperature reinjected to the earth. The brine with low grade temperature can be converted indirectly to electrical power by organic Rankine cycle (ORC) methods. In ORC power plant the steam are released from vaporization of organic working fluid by brine. The steam released are used to drive an turbine which in connected to generator to convert the mechanical energy into electric energy. The objective of this research is the simulation ORC power plant with n-pentane as organic working fluid. The result of the simulation for brine temperature around 165°C and the pressure 8.001 bar optained the net electric power around 1173 kW with the cycle thermal efficiency 14.61% and the flow rate of n-pentane around 15.51 kg/s. This result enable to applied in any geothermal source in Indonesia.

  20. Thermo-Economic Evaluation of Organic Rankine Cycles for Geothermal Power Generation Using Zeotropic Mixtures

    Directory of Open Access Journals (Sweden)

    Florian Heberle

    2015-03-01

    Full Text Available We present a thermo-economic evaluation of binary power plants based on the Organic Rankine Cycle (ORC for geothermal power generation. The focus of this study is to analyse if an efficiency increase by using zeotropic mixtures as working fluid overcompensates additional requirements regarding the major power plant components. The optimization approach is compared to systems with pure media. Based on process simulations, heat exchange equipment is designed and cost estimations are performed. For heat source temperatures between 100 and 180 °C selected zeotropic mixtures lead to an increase in second law efficiency of up to 20.6% compared to pure fluids. Especially for temperatures about 160 °C, mixtures like propane/isobutane, isobutane/isopentane, or R227ea/R245fa show lower electricity generation costs compared to the most efficient pure fluid. In case of a geothermal fluid temperature of 120 °C, R227ea and propane/isobutane are cost-efficient working fluids. The uncertainties regarding fluid properties of zeotropic mixtures, mainly affect the heat exchange surface. However, the influence on the determined economic parameter is marginal. In general, zeotropic mixtures are a promising approach to improve the economics of geothermal ORC systems. Additionally, the use of mixtures increases the spectrum of potential working fluids, which is important in context of present and future legal requirements considering fluorinated refrigerants.

  1. Experimental and Thermoeconomic Analysis of Small-Scale Solar Organic Rankine Cycle (SORC System

    Directory of Open Access Journals (Sweden)

    Suresh Baral

    2015-04-01

    Full Text Available A small-scale solar organic Rankine cycle (ORC is a promising renewable energy-driven power generation technology that can be used in the rural areas of developing countries. A prototype was developed and tested for its performance characteristics under a range of solar source temperatures. The solar ORC system power output was calculated based on the thermal and solar collector efficiency. The maximum solar power output was observed in April. The solar ORC unit power output ranged from 0.4 kW to 1.38 kW during the year. The highest power output was obtained when the expander inlet pressure was 13 bar and the solar source temperature was 120 °C. The area of the collector for the investigation was calculated based on the meteorological conditions of Busan City (South Korea. In the second part, economic and thermoeconomic analyses were carried out to determine the cost of energy per kWh from the solar ORC. The selling price of electricity generation was found to be $0.68/kWh and $0.39/kWh for the prototype and low cost solar ORC, respectively. The sensitivity analysis was carried out in order to find the influencing economic parameters for the change in NPV. Finally, the sustainability index was calculated to assess the sustainable development of the solar ORC system.

  2. Evaluation of a solar-powered organic Rankine cycle using dry organic working fluids

    Directory of Open Access Journals (Sweden)

    Emily Spayde

    2015-12-01

    Full Text Available This paper presents a model to evaluate the performance of a solar-powered organic Rankine cycle (ORC. The system was evaluated in Jackson, MS, using five dry organic working fluids, R218, R227ea, R236ea, R236fa, and RC318. The purpose of this study is to investigate how hourly temperature change affects the electricity production and exergy destruction rates of the solar ORC, and to determine the effect of the working fluid on the proposed system. The system was also evaluated in Tucson, AZ, to investigate the effect of average hourly outdoor temperatures on its performance. The potential of the system to reduce primary energy consumption and carbon dioxide emissions is also investigated. A parametric analysis to determine how temperature and pressure of the organic working fluid, the solar collector area, and the turbine efficiency affect the electricity production is performed. Results show that the ORC produces the most electricity during the middle of the day, when the temperatures are the highest and when the solar collectors have the highest efficiency. Also, R-236ea is the working fluid that shows the best performance of the evaluated fluids. An economic analysis was performed to determine the capital cost available for the proposed system.

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

    Science.gov (United States)

    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.

  4. Part-Load Performance of aWet Indirectly Fired Gas Turbine Integrated with an Organic Rankine Cycle Turbogenerator

    Directory of Open Access Journals (Sweden)

    Leonardo Pierobon

    2014-12-01

    Full Text Available Over the last years, much attention has been paid to the development of efficient and low-cost power systems for biomass-to-electricity conversion. This paper aims at investigating the design- and part-load performance of an innovative plant based on a wet indirectly fired gas turbine (WIFGT fueled by woodchips and an organic Rankine cycle (ORC turbogenerator. An exergy analysis is performed to identify the sources of inefficiencies, the optimal design variables, and the most suitable working fluid for the organic Rankine process. This step enables to parametrize the part-load model of the plant and to estimate its performance at different power outputs. The novel plant has a nominal power of 250 kW and a thermal efficiency of 43%. The major irreversibilities take place in the burner, recuperator, compressor and in the condenser. Toluene is the optimal working fluid for the organic Rankine engine. The part-load investigation indicates that the plant can operate at high efficiencies over a wide range of power outputs (50%–100%, with a peak thermal efficiency of 45% at around 80% load. While the ORC turbogenerator is responsible for the efficiency drop at low capacities, the off-design performance is governed by the efficiency characteristics of the compressor and turbine serving the gas turbine unit.

  5. A Comparative Exergoeconomic Analysis of Waste Heat Recovery from a Gas Turbine-Modular Helium Reactor via Organic Rankine Cycles

    Directory of Open Access Journals (Sweden)

    Naser Shokati

    2014-04-01

    Full Text Available A comparative exergoeconomic analysis is reported for waste heat recovery from a gas turbine-modular helium reactor (GT-MHR using various configurations of organic Rankine cycles (ORCs for generating electricity. The ORC configurations studied are: a simple organic Rankine cycle (SORC, an ORC with an internal heat exchanger (HORC and a regenerative organic Rankine cycle (RORC. Exergoeconomic analyses are performed with the specific exergy costing (SPECO method. First, energy and exergy analyses are applied to the combined cycles. Then, a cost-balance, as well as auxiliary equations are developed for the components to determine the exergoeconomic parameters for the combined cycles and their components. The three combined cycles are compared considering the same operating conditions for the GT-MHR cycle, and a parametric study is done to reveal the effects on the exergoeconomic performance of the combined cycles of various significant parameters, e.g., turbine inlet and evaporator temperatures and compressor pressure ratio. The results show that the GT-MHR/RORC has the lowest unit cost of electricity generated by the ORC turbine. This value is highest for the GT-MHR/HORC. Furthermore, the GT-MHR/RORC has the highest and the GT-MHR/HORC has the lowest exergy destruction cost rate.

  6. Effect of Regenerative Organic Rankine Cycle (RORC on the Performance of Solar Thermal Power in Yogyakarta, Indonesia

    Directory of Open Access Journals (Sweden)

    Ghalya Pikra

    2013-07-01

    Full Text Available This paper presents effect of Regenerative Organic Rankine Cycle (RORC on the performance of solar thermal power in Yogyakarta, Indonesia. Solar thermal power is a plant that uses solar energy as heat source. Indonesia has high humidity level, so that parabolic trough is the most suitable type of solar thermal power technology to be developed, where the design is made with small focal distance. Organic Rankine Cycle (ORC is a Rankine cycle that use organic fluid as working fluid to utilize low temperature heat sources. RORC is used to increase ORC performance. The analysis was done by comparing ORC system with and without regenerator addition. Refrigerant that be used in the analysis is R123. Preliminary data was taken from the solar collector system that has been installed in Yogyakarta. The analysis shows that with 36 m total parabolic length, the resulting solar collector capacity is 63 kW, heat input/evaporator capacity is determined 26.78 kW and turbine power is 3.11 kW for ORC, and 3.38 kW for RORC. ORC thermal efficiency is 11.28% and RORC is 12.26%. Overall electricity efficiency is 4.93% for ORC, and 5.36% for RORC. With 40°C condensing temperature and evaporation at 10 bar saturated condition, efficiency of RORC is higher than ORC. Greater evaporation temperature at the same pressure (10 bar provide greater turbine power and efficiency.

  7. Performance of a reversible heat pump/organic Rankine cycle unit coupled with a passive house to get a positive energy building

    DEFF Research Database (Denmark)

    Dumont, Olivier; Carmo, Carolina; Fontaine, Valentin

    2016-01-01

    and generate electricity, coupled to a solar thermal collector roof. This reversible HP/organic Rankine cycle unit presents three operating modes: direct heating, HP and organic Rankine cycle. This work focuses on describing the dynamic model of the multi-component system followed by a techno-economic analysis......Wh/year and total electrical consumption of 2318 kWh/year) with a 138.8 m2 solar roof in Denmark....

  8. Measurement method of reverberation field reciprocity parameter

    Directory of Open Access Journals (Sweden)

    SUN Jundong

    2017-08-01

    Full Text Available This paper presents a method for measuring the reciprocity parameter based on the free field. It is able to achieve accurate measurement of the reverberation constant in a narrow band. The method uses the same transmitting and receiving system, and keeps the same set of parameters to measure the open circuit voltage output under different frequencies in a free field. The open circuit output voltage is measured through average technology in the reverberation control region, then the reverberation radius is calculated and the reciprocity constant obtained. This method uses a single frequency signal and the spatial averaging technique. It is simple, convenient and not suitable for complex measuring instruments. The validity of the method is verified by comparing the measured results with the reverberation time measurement.

  9. Reciprocity as a Foundation of Financial Economics.

    Science.gov (United States)

    Johnson, Timothy C

    This paper argues that the subsistence of the fundamental theorem of contemporary financial mathematics is the ethical concept 'reciprocity'. The argument is based on identifying an equivalence between the contemporary, and ostensibly 'value neutral', Fundamental Theory of Asset Pricing with theories of mathematical probability that emerged in the seventeenth century in the context of the ethical assessment of commercial contracts in a framework of Aristotelian ethics. This observation, the main claim of the paper, is justified on the basis of results from the Ultimatum Game and is analysed within a framework of Pragmatic philosophy. The analysis leads to the explanatory hypothesis that markets are centres of communicative action with reciprocity as a rule of discourse. The purpose of the paper is to reorientate financial economics to emphasise the objectives of cooperation and social cohesion and to this end, we offer specific policy advice.

  10. Exposure to Hedione Increases Reciprocity in Humans

    Directory of Open Access Journals (Sweden)

    Sebastian Berger

    2017-05-01

    Full Text Available Cooperation among unrelated humans is frequently regarded as a defining feature in the evolutionary success of our species. Whereas, much research has addressed the strategic and cognitive mechanisms that underlie cooperation, investigations into chemosensory processes have received very limited research attention. To bridge that gap, we build on recent research that has identified the chemically synthesized odorant Hedione (HED as a ligand for the putative human pheromone receptor (VN1R1 expressed in the olfactory mucosa, and hypothesize that exposure to HED may increase reciprocity. Applying behavioral economics paradigms, the present research shows that exposure to the ligand causes differentiated behavioral effects in reciprocal punishments (Study 1 as well as rewards (Study 2, two types of behaviors that are frequently regarded as essential for the development and maintenance of cooperation.

  11. Effect of slab reheating temperature on recrystallization microstructure, texture and magnetic properties of Nb-containing grain-oriented silicon steel

    Science.gov (United States)

    Feng, Yunli; Li, Yang; Guo, Jing; Li, Jie; Du, Tiantian

    2017-10-01

    In this study, a Nb-containing grain-oriented silicon steel was chosen to investigate the effect of different slab reheating temperatures on the microstructure and texture of primary recrystallization and secondary recrystallization by optical microscope (OM), field emission scanning electron microscope (FE-SEM) equipped with electron backscatter diffraction (EBSD) system and transmission electron microscope (TEM). The magnetic properties of finished product were also measured. The results show that Nb(C,N) can be formed and worked as the main inhibitor after adding Nb into the traditional grain-oriented silicon steel to lower the reheating temperature of the slab. At different low slab reheating temperatures, primary recrystallization takes place in all decarburized specimens, and at 1220 °C, the microstructure is the most fine and uniform. The types of primary recrystallization texture are consistent composed of strong {4 1 1} texture, dominated γ-fiber texture {1 1 1} and {1 1 1}, weak α-fiber texture and some Goss components. The proportions of HEGB and Σ9 boundary are the highest at 1220 °C after decarburization annealing, which is beneficial to the grain growth of primary recrystallization. After high temperature annealing, the specimen of 1220 °C slab reheating temperature can be fully recrystallized to obtain secondary recrystallization grains on the centimeter scale, and the texture component is characterized by a single Goss texture. The magnetic properties of finished product are the best, and B800 = 1.88 T, P1.7/50 = 1.31 W/kg.

  12. Reciprocity in Organisations - Evidence from the WERS

    OpenAIRE

    Florian Englmaier; Thomas Kolaska; Stephen G. Leider

    2015-01-01

    Recent laboratory evidence suggests that social preferences may affect contractual outcomes under moral hazard. In accordance with previous research, this paper uses written personality tests for job candidates as a proxy for whether firms care about personality traits of employees, in particular whether these employees are inclined towards reciprocity. Using the British Workplace Employment Relations Survey 2004 (WERS) we find that behavior of employers and employees is consistent with the p...

  13. Effect of heating/reheating of fats/oils, as used by Asian Indians, on trans fatty acid formation.

    Science.gov (United States)

    Bhardwaj, Swati; Passi, Santosh Jain; Misra, Anoop; Pant, Kamal K; Anwar, Khalid; Pandey, R M; Kardam, Vikas

    2016-12-01

    Heating/frying and reuse of edible fats/oils induces chemical changes such as formation of trans fatty acids (TFAs). The aim of this study was to investigate the effect of heating/frying on formation of TFAs in fats/oils. Using gas chromatography with flame ionisation detector, TFA was estimated in six commonly used fat/oils in India (refined soybean oil, groundnut oil, olive oil, rapeseed oil, clarified butter, partially hydrogenated vegetable oil), before and after subjecting them to heating/frying at 180°C and 220°C. All six fats/oils subjected to heating/frying demonstrated an increase in TFAs (poils (after subjecting to heating/reheating) ranged between 2.30±0.89g/100g and 4.5±1.43g/100g; amongst edible fats it ranged between 2.60±0.38g/100g and 5.96±1.94g/100g. There were no significant differences between the two treatment groups (heating and frying; p=0.892). Considering the undesirable health effects of TFA, appropriate guidelines for heating/re-frying of edible fats/oils by Asian Indians should be devised. Copyright © 2016 Elsevier Ltd. All rights reserved.

  14. Correlation Between Microstructure and Low-Temperature Impact Toughness of Simulated Reheated Zones in the Multi-pass Weld Metal of High-Strength Steel

    Science.gov (United States)

    Kang, Yongjoon; Park, Gitae; Jeong, Seonghoon; Lee, Changhee

    2018-01-01

    A large fraction of reheated weld metal is formed during multi-pass welding, which significantly affects the mechanical properties (especially toughness) of welded structures. In this study, the low-temperature toughness of the simulated reheated zone in multi-pass weld metal was evaluated and compared to that of the as-deposited zone using microstructural analyses. Two kinds of high-strength steel welds with different hardenabilities were produced by single-pass, bead-in-groove welding, and both welds were thermally cycled to peak temperatures above Ac3 using a Gleeble simulator. When the weld metals were reheated, their toughness deteriorated in response to the increase in the fraction of detrimental microstructural components, i.e., grain boundary ferrite and coalesced bainite in the weld metals with low and high hardenabilities, respectively. In addition, toughness deterioration occurred in conjunction with an increase in the effective grain size, which was attributed to the decrease in nucleation probability of acicular ferrite; the main cause for this decrease changed depending on the hardenability of the weld metal.

  15. Design of steam turbine for 593[degree]C reheat temperature. Sainetsu joki ondo 593[degree]C turbine no keikaku

    Energy Technology Data Exchange (ETDEWEB)

    Matsukuma, M.; Fujikawa, T.; Takayanagi, K. (Mitsubishi Heavy Industries, Ltd., Tokyo (Japan))

    1993-02-15

    Following the successful completion of the first stage operation with main/reheat steam temperature of 593/593 centigrade for the Wakamatsu high temperature 50MW turbine of Electric Power Development Co., the large high temperature steam turbines for the hot reheat temperature of 593 centigrade are currently being realized for the first time in Japan. Namely, the Hekinan No.3 unit of Chubu Electric Power Company is being constructed, which has 246kg/cm[sup 2], 538/593 centigrade 700MW turbine, and the design of the Nanao-Ohta No.1 unit of Hokuriku Electric Power Company is in progress, which has 246kg/cm[sup 2], 566/593 centigrade 500MW turbine. The present paper describes the results of demonstration tests of the Wakamatsu high temperature turbine conducted for three years and three months from 1986 to 1990, and introduces outline of development, features in the design, and problems to be considered of these high temperature steam turbines designed for the 593 centigrade hot reheat steam temperature. 15 figs., 2 tabs.

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

    Science.gov (United States)

    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

  17. Development and a Validation of a Charge Sensitive Organic Rankine Cycle (ORC Simulation Tool

    Directory of Open Access Journals (Sweden)

    Davide Ziviani

    2016-05-01

    Full Text Available Despite the increasing interest in organic Rankine cycle (ORC systems and the large number of cycle models proposed in the literature, charge-based ORC models are still almost absent. In this paper, a detailed overall ORC simulation model is presented based on two solution strategies: condenser subcooling and total working fluid charge of the system. The latter allows the subcooling level to be predicted rather than specified as an input. The overall cycle model is composed of independent models for pump, expander, line sets, liquid receiver and heat exchangers. Empirical and semi-empirical models are adopted for the pump and expander, respectively. A generalized steady-state moving boundary method is used to model the heat exchangers. The line sets and liquid receiver are used to better estimate the total charge of the system and pressure drops. Finally, the individual components are connected to form a cycle model in an object-oriented fashion. The solution algorithm includes a preconditioner to guess reasonable values for the evaporating and condensing temperatures and a main cycle solver loop which drives to zero a set of residuals to ensure the convergence of the solution. The model has been developed in the Python programming language. A thorough validation is then carried out against experimental data obtained from two test setups having different nominal size, working fluids and individual components: (i a regenerative ORC with a 5 kW scroll expander and an oil flooding loop; (ii a regenerative ORC with a 11 kW single-screw expander. The computer code is made available through open-source dissemination.

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

    Energy Technology Data Exchange (ETDEWEB)

    Dieckmann, John [TIAX LLC, Lexington, MA (United States); Smutzer, Chad [TIAX LLC, Lexington, MA (United States); Sinha, Jayanti [TIAX LLC, Lexington, MA (United States)

    2017-05-30

    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 of 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.

  19. Stand-Alone Solar Organic Rankine Cycle Water Pumping System and Its Economic Viability in Nepal

    Directory of Open Access Journals (Sweden)

    Suresh Baral

    2015-12-01

    Full Text Available The current study presents the concept of a stand-alone solar organic Rankine cycle (ORC water pumping system for rural Nepalese areas. Experimental results for this technology are presented based on a prototype. The economic viability of the system was assessed based on solar radiation data of different Nepalese geographic locations. The mechanical power produced by the solar ORC is coupled with a water pumping system for various applications, such as drinking and irrigation. The thermal efficiency of the system was found to be 8% with an operating temperature of 120 °C. The hot water produced by the unit has a temperature of 40 °C. Economic assessment was done for 1-kW and 5-kW solar ORC water pumping systems. These systems use different types of solar collectors: a parabolic trough collector (PTC and an evacuated tube collector (ETC. The economic analysis showed that the costs of water are $2.47/m3 (highest and $1.86/m3 (lowest for the 1-kW system and a 150-m pumping head. In addition, the cost of water is reduced when the size of the system is increased and the pumping head is reduced. The minimum volumes of water pumped are 2190 m3 and 11,100 m3 yearly for 1 kW and 5 kW, respectively. The payback period is eight years with a profitability index of 1.6. The system is highly feasible and promising in the context of Nepal.

  20. Thermo-Economic Performance Analysis of a Regenerative Superheating Organic Rankine Cycle for Waste Heat Recovery

    Directory of Open Access Journals (Sweden)

    Zhonghe Han

    2017-10-01

    Full Text Available The Organic Rankine Cycle (ORC is a promising form of technology for recovering low-grade waste heat. In this study, a regenerative ORC system is established to recover the waste flue gas of 160 °C. Focusing on thermodynamic and economic performance while simultaneously considering the limitations of volume flow ratio (VFR and the effect of superheat, working fluid selection and parameter optimization have been investigated. The optimization of the evaporation temperature is carried out by analyzing the variation of net power output and specific investment cost (SIC. Then, the net power output, specific net power output, total exergy destruction rate, VFR, total capital cost, and levelized electricity cost (LEC are selected as criteria, and a fuzzy multi-criteria evaluation method is adopted to select a more suitable working fluid and determine the optimal degree of superheat. In addition, the preheating coefficient, latent heat coefficient, superheating coefficient, and internal heat coefficient were proposed to explore the effect of working fluid critical temperature on thermal efficiency. Research studies demonstrate that there is an optimal evaporation temperature, maximizing net power output and minimizing the SIC. Isohexane and butane have greater specific net power output due to greater latent heat. A suitable degree of superheat is not only conducive to improving the working capacity of working fluids, but also reduces the VFR, total capital cost, SIC, and LEC for different working fluids. Thus, the system’s thermodynamic and economic performance—as well as the operational stability—are improved. Among the six working fluids, butane exhibits the best comprehensive performance, and its optimal evaporation temperature and degree of superheat are 100 °C and 5 °C, respectively.

  1. Applied studies in advanced boiler technology for Rankine cycle power systems

    Energy Technology Data Exchange (ETDEWEB)

    Paul, F.W.; Negreanu, M.J.

    1978-02-01

    A study is presented on a new rotational boiler design which has improved passive dynamic response and two-phase flow stability characteristics. A survey of small boiler manufacturers in the United States indicated that currently available designs are based on steady-state operating requirements rather than for dynamic performance. Recent work by EPA and ERDA which addressed boiler designs for mobile automotive Rankine cycle power systems showed that boilers of a monotube or multipass tube configuration design could be developed which were physically compact, but still were subject to the two-phase flow instability problem when coupled within an operating power system. The objectives of this work were to evaluate alternative boiler configurations which would improve boiler dynamic response and also have good two-phase liquid-vapor interface flow stability. The major physical design limitation of any boiler is the small external hot gas heat transfer coefficient. Such a low coefficient requires considerable design enhancements to increase the rate of energy transfer to the circulation system fluid. The rotational boiler is a physical design configuration which addresses this problem. The results of an analytic study using several mathematical model formulations showed that a rotational boiler could have a passive response time constant which was approximately one-half the magnitude for an equivalent single pass monotube boiler. An experimental prototype rotational boiler was designed, manufactured and tested, with the experimental results confirming that the experimental passive response time constants were comparable to the estimates from the analytic models. The experimental boiler operating in two-phase flow was found to be stable and responsive to external inputs. A rotational boiler configuration is a good alternative design configuration for small compact vapor generator designs based on fast transient passive response and two-phase flow stability.

  2. Thermodynamic Optimization of a Geothermal- Based Organic Rankine Cycle System Using an Artificial Bee Colony Algorithm

    Directory of Open Access Journals (Sweden)

    Osman Özkaraca

    2017-10-01

    Full Text Available Geothermal energy is a renewable form of energy, however due to misuse, processing and management issues, it is necessary to use the resource more efficiently. To increase energy efficiency, energy systems engineers carry out careful energy control studies and offer alternative solutions. With this aim, this study was conducted to improve the performance of a real operating air-cooled organic Rankine cycle binary geothermal power plant (GPP and its components in the aspects of thermodynamic modeling, exergy analysis and optimization processes. In-depth information is obtained about the exergy (maximum work a system can make, exergy losses and destruction at the power plant and its components. Thus the performance of the power plant may be predicted with reasonable accuracy and better understanding is gained for the physical process to be used in improving the performance of the power plant. The results of the exergy analysis show that total exergy production rate and exergy efficiency of the GPP are 21 MW and 14.52%, respectively, after removing parasitic loads. The highest amount of exergy destruction occurs, respectively, in condenser 2, vaporizer HH2, condenser 1, pumps 1 and 2 as components requiring priority performance improvement. To maximize the system exergy efficiency, the artificial bee colony (ABC is applied to the model that simulates the actual GPP. Under all the optimization conditions, the maximum exergy efficiency for the GPP and its components is obtained. Two of these conditions such as Case 4 related to the turbine and Case 12 related to the condenser have the best performance. As a result, the ABC optimization method provides better quality information than exergy analysis. Based on the guidance of this study, the performance of power plants based on geothermal energy and other energy resources may be improved.

  3. Realizing total reciprocity violation in the phase for photon scattering.

    Science.gov (United States)

    Deák, László; Bottyán, László; Fülöp, Tamás; Merkel, Dániel Géza; Nagy, Dénes Lajos; Sajti, Szilárd; Schulze, Kai Sven; Spiering, Hartmut; Uschmann, Ingo; Wille, Hans-Christian

    2017-02-22

    Reciprocity is when wave or quantum scattering satisfies a symmetry property, connecting a scattering process with the reversed one. While reciprocity involves the interchange of source and detector, it is fundamentally different from rotational invariance, and is a generalization of time reversal invariance, occurring in absorptive media as well. Due to its presence at diverse areas of physics, it admits a wide variety of applications. For polarization dependent scatterings, reciprocity is often violated, but violation in the phase of the scattering amplitude is much harder to experimentally observe than violation in magnitude. Enabled by the advantageous properties of nuclear resonance scattering of synchrotron radiation, we have measured maximal, i.e., 180-degree, reciprocity violation in the phase. For accessing phase information, we introduced a new version of stroboscopic detection. The scattering setting was devised based on a generalized reciprocity theorem that opens the way to construct new types of reciprocity related devices.

  4. Mortality salience increases personal relevance of the norm of reciprocity.

    Science.gov (United States)

    Schindler, Simon; Reinhard, Marc-André; Stahlberg, Dagmar

    2012-10-01

    Research on terror management theory found evidence that people under mortality salience strive to live up to salient cultural norms and values, like egalitarianism, pacifism, or helpfulness. A basic, strongly internalized norm in most human societies is the norm of reciprocity: people should support those who supported them (i.e., positive reciprocity), and people should injure those who injured them (i.e., negative reciprocity), respectively. In an experiment (N = 98; 47 women, 51 men), mortality salience overall significantly increased personal relevance of the norm of reciprocity (M = 4.45, SD = 0.65) compared to a control condition (M = 4.19, SD = 0.59). Specifically, under mortality salience there was higher motivation to punish those who treated them unfavourably (negative norm of reciprocity). Unexpectedly, relevance of the norm of positive reciprocity remained unaffected by mortality salience. Implications and limitations are discussed.

  5. REGIONAL RECIPROCAL GUARANTEE SOCIETIES IN VENEZUELA

    Directory of Open Access Journals (Sweden)

    Orlando J. Canelones

    2014-11-01

    Full Text Available This research aims to describe the operation of services offered by the Regional Mutual Guarantee Societies (SGRs in Venezuela, and to present synthetically, the rudiments for constitution, as well as the legal basis that must rule them, through conducting an executive summary of the Law of the National System of Reciprocal Guarantees for Small and Medium Business and the Promotion, Constitution and Functioning Rules of National Mutual Funds and Guarantees and SGRs.  The methodology used in this research is documentary, through a literature review and exploration that allowed inferences about the importance of Regional SGRs in Venezuela, as financing alternative

  6. Reinforcement learning account of network reciprocity.

    Directory of Open Access Journals (Sweden)

    Takahiro Ezaki

    Full Text Available Evolutionary game theory predicts that cooperation in social dilemma games is promoted when agents are connected as a network. However, when networks are fixed over time, humans do not necessarily show enhanced mutual cooperation. Here we show that reinforcement learning (specifically, the so-called Bush-Mosteller model approximately explains the experimentally observed network reciprocity and the lack thereof in a parameter region spanned by the benefit-to-cost ratio and the node's degree. Thus, we significantly extend previously obtained numerical results.

  7. Integral inequalities for self-reciprocal polynomials

    Indian Academy of Sciences (India)

    Self-reciprocal polynomials. 133 where xj = (N − k)/(N − j) ∈ (0, 1) for j = 0, 1,...,r − 1. Let Qr be the expression on the right-hand side of (2.4). We have. Q1 = 2x2. 0 + 2 ≥ 2. And, if Qr ≥ 2, then. Qr+1 = (1 − xr)2Qr + 4xr r−1. ∏ j=0. (1 + xj )2. ≥ 2(1 − xr)2 + 4xr = 2 + 2x2 r ≥ 2. By induction, we conclude that (2.4) holds for all r ...

  8. On the sums of series of reciprocals

    OpenAIRE

    Euler, Leonhard

    2005-01-01

    This translation has been published in Stephen Hawking (ed.), "God Created the Integers", published in 2007 by Running Press. There may have been some changes to the final published version and this copy. This is a translation from the Latin original, "De summis serierum reciprocarum" (1735). E41 in the Enestrom index. In this paper Euler finds an exact expression for the sum of the squares of the reciprocals of the positive integers, namely pi^2/6. He shows this by applying Newton's identiti...

  9. Neural correlate of human reciprocity in social interactions

    Directory of Open Access Journals (Sweden)

    Shiro eSakaiya

    2013-12-01

    Full Text Available Reciprocity plays a key role maintaining cooperation in society. However, little is known about the neural process that underpins human reciprocity during social interactions. Our neuroimaging study manipulated partner identity (computer, human and strategy (random, tit-for-tat in repeated prisoner’s dilemma games and investigated the neural correlate of reciprocal interaction with humans. Reciprocal cooperation with humans but exploitation of computers by defection was associated with activation in the left amygdala. Amygdala activation was also positively and negatively correlated with a preference change for human partners following tit-for-tat and random strategies, respectively. The correlated activation represented the intensity of positive feeling toward reciprocal and negative feeling toward non-reciprocal partners, and so reflected reciprocity in social interaction. Reciprocity in social interaction, however, might plausibly be misinterpreted and so we also examined the neural coding of insight into the reciprocity of partners. Those with and without insight revealed differential brain activation across the reward-related circuitry (i.e., the right middle dorsolateral prefrontal cortex and dorsal caudate and theory of mind (ToM regions (i.e., ventromedial prefrontal cortex [VMPFC] and precuneus. Among differential activations, activation in the precuneus, which accompanied deactivation of the VMPFC, was specific to those without insight into human partners who were engaged in a tit-for-tat strategy. This asymmetric (deactivation might involve specific contributions of ToM regions to the human search for reciprocity. Consequently, the intensity of emotion attached to human reciprocity was represented in the amygdala, whereas insight into the reciprocity of others was reflected in activation across the reward-related and ToM regions. This suggests the critical role of mentalizing, which was not equated with reward expectation during

  10. Non-reciprocal geometric phase in nonlinear frequency conversion.

    Science.gov (United States)

    Wang, Kai; Shi, Yu; Solntsev, Alexander S; Fan, Shanhui; Sukhorukov, Andrey A; Neshev, Dragomir N

    2017-05-15

    We describe analytically and numerically the geometric phase arising from nonlinear frequency conversion and show that such a phase can be made non-reciprocal by momentum-dependent photonic transition. Such non-reciprocity is immune to the shortcomings imposed by dynamic reciprocity in Kerr and Kerr-like devices. We propose a simple and practical implementation, requiring only a single waveguide and one pump, while the geometric phase is controllable by the pump and promises robustness against fabrication errors.

  11. Neural correlate of human reciprocity in social interactions.

    Science.gov (United States)

    Sakaiya, Shiro; Shiraito, Yuki; Kato, Junko; Ide, Hiroko; Okada, Kensuke; Takano, Kouji; Kansaku, Kenji

    2013-01-01

    Reciprocity plays a key role maintaining cooperation in society. However, little is known about the neural process that underpins human reciprocity during social interactions. Our neuroimaging study manipulated partner identity (computer, human) and strategy (random, tit-for-tat) in repeated prisoner's dilemma games and investigated the neural correlate of reciprocal interaction with humans. Reciprocal cooperation with humans but exploitation of computers by defection was associated with activation in the left amygdala. Amygdala activation was also positively and negatively correlated with a preference change for human partners following tit-for-tat and random strategies, respectively. The correlated activation represented the intensity of positive feeling toward reciprocal and negative feeling toward non-reciprocal partners, and so reflected reciprocity in social interaction. Reciprocity in social interaction, however, might plausibly be misinterpreted and so we also examined the neural coding of insight into the reciprocity of partners. Those with and without insight revealed differential brain activation across the reward-related circuitry (i.e., the right middle dorsolateral prefrontal cortex and dorsal caudate) and theory of mind (ToM) regions [i.e., ventromedial prefrontal cortex (VMPFC) and precuneus]. Among differential activations, activation in the precuneus, which accompanied deactivation of the VMPFC, was specific to those without insight into human partners who were engaged in a tit-for-tat strategy. This asymmetric (de)activation might involve specific contributions of ToM regions to the human search for reciprocity. Consequently, the intensity of emotion attached to human reciprocity was represented in the amygdala, whereas insight into the reciprocity of others was reflected in activation across the reward-related and ToM regions. This suggests the critical role of mentalizing, which was not equated with reward expectation during social interactions.

  12. Institutionalize Reciprocity to Overcome the Public Goods Provision Problem.

    Directory of Open Access Journals (Sweden)

    Hiroki Ozono

    Full Text Available Cooperation is fundamental to human societies, and one of the important paths for its emergence and maintenance is reciprocity. In prisoner's dilemma (PD experiments, reciprocal strategies are often effective at attaining and maintaining high cooperation. In many public goods (PG games or n-person PD experiments, however, reciprocal strategies are not successful at engendering cooperation. In the present paper, we attribute this difficulty to a coordination problem against free riding among reciprocators: Because it is difficult for the reciprocators to coordinate their behaviors against free riders, this may lead to inequality among players, which will demotivate them from cooperating in future rounds. We propose a new mechanism, institutionalized reciprocity (IR, which refers to embedding the reciprocal strategy as an institution (i.e., institutionalizing the reciprocal strategy. We experimentally demonstrate that IR can prevent groups of reciprocators from falling into coordination failure and achieve high cooperation in PG games. In conclusion, we argue that a natural extension of the present study will be to investigate the possibility of IR to serve as a collective punishment system.

  13. Institutionalize Reciprocity to Overcome the Public Goods Provision Problem.

    Science.gov (United States)

    Ozono, Hiroki; Kamijo, Yoshio; Shimizu, Kazumi

    2016-01-01

    Cooperation is fundamental to human societies, and one of the important paths for its emergence and maintenance is reciprocity. In prisoner's dilemma (PD) experiments, reciprocal strategies are often effective at attaining and maintaining high cooperation. In many public goods (PG) games or n-person PD experiments, however, reciprocal strategies are not successful at engendering cooperation. In the present paper, we attribute this difficulty to a coordination problem against free riding among reciprocators: Because it is difficult for the reciprocators to coordinate their behaviors against free riders, this may lead to inequality among players, which will demotivate them from cooperating in future rounds. We propose a new mechanism, institutionalized reciprocity (IR), which refers to embedding the reciprocal strategy as an institution (i.e., institutionalizing the reciprocal strategy). We experimentally demonstrate that IR can prevent groups of reciprocators from falling into coordination failure and achieve high cooperation in PG games. In conclusion, we argue that a natural extension of the present study will be to investigate the possibility of IR to serve as a collective punishment system.

  14. Sleep Health: Reciprocal Regulation of Sleep and Innate Immunity

    National Research Council Canada - National Science Library

    Irwin, Michael R; Opp, Mark R

    2017-01-01

    ...://www.neuropsychopharmacologyreviews.org Web End =www.neuropsychopharmacologyreviews.org 129 Sleep Health: Reciprocal Regulation of Sleep and Innate Immunity [notdef][notdef][notdef][notdef][notdef...

  15. Electromagnetic Reciprocal Cloak with Only Axial Material Parameter Spatially Variant

    Directory of Open Access Journals (Sweden)

    Jing Jing Yang

    2012-01-01

    Full Text Available Reciprocal cloak is an intriguing metamaterial device, in which a hidden antenna or a sensor can receive electromagnetic irradiation from the outside but its presence will not be detected. Based on transformation optics, a cylindrical electromagnetic reciprocal cloak with only axial parameter varying with radius is designed and validated by full wave simulation. When two dispersive reciprocal cloaks are put together, they do not interfere with each other. Our work demonstrates the electromagnetic compatibility (EMC ability of the reciprocal cloak which is very important in multi antenna and sensor design.

  16. Near optimal graphene terahertz non-reciprocal isolator

    National Research Council Canada - National Science Library

    Tamagnone, Michele; Moldovan, Clara; Poumirol, Jean-Marie; Kuzmenko, Alexey B; Ionescu, Adrian M; Mosig, Juan R; Perruisseau-Carrier, Julien

    2016-01-01

    .... Here we report the design, fabrication and measurement of a terahertz non-reciprocal isolator for circularly polarized waves based on magnetostatically biased monolayer graphene, operating in reflection...

  17. Efficient Design And Fabrication Of Free-Form Reciprocal Structures

    DEFF Research Database (Denmark)

    Parigi, Dario; Kirkegaard, Poul Henning

    2013-01-01

    Structures based on the principle of reciprocity have been autonomously studied and used since the antiquity on the basis of different needs and purposes. The application of the principle of reciprocity requires the presence of at least two elements, at the same time both supporting and being...... supported by the other with no hierarchy, meeting along their span and never in their vertices. A computational method has been developed to predict and control the geometry of large networks of reciprocally connected, round un-notched elements. The method enables the possibility of using reciprocal...

  18. Advanced Natural Gas Reciprocating Engines(s)

    Energy Technology Data Exchange (ETDEWEB)

    Zurlo, James [Dresser, Inc., Addison, TX (United States)

    2012-04-05

    The ARES program was initiated in 2001 to improve the overall brake thermal efficiency of stationary, natural gas, reciprocating engines. The ARES program is a joint award that is shared by Dresser, Inc., Caterpillar and Cummins. The ARES program was divided into three phases; ARES I (achieve 44% BTE), ARES II (achieve 47% BTE) and ARES III (achieve 50% BTE). Dresser, Inc. completed ARES I in March 2005 which resulted in the commercialization of the APG1000 product line. ARES II activities were completed in September 2010 and the technology developed is currently being integrated into products. ARES III activities began in October 2010. The ARES program goal is to improve the efficiency of natural gas reciprocating engines. The ARES project is structured in three phases with higher efficiency goals in each phase. The ARES objectives are as follows: 1. Achieve 44% (ARES I), 47% (ARES II), and 50% brake thermal efficiency (BTE) as a final ARES III objective 2. Achieve 0.1 g/bhp-hr NOx emissions (with after-treatment) 3. Reduce the cost of the produced electricity by 10% 4. Improve or maintain reliability, durability and maintenance costs

  19. Altheim geothermal plant. Power generation by means of an ORC turbogenerator; Geothermieanlagen Altheim. Stromerzeugung mittels Organic-Rankine-Cycle Turbogenerator

    Energy Technology Data Exchange (ETDEWEB)

    Pernecker, G. [Marktgemeindeamt Altheim (Austria)

    1997-12-01

    The report describes the project of the Austrian market town of Altheim to generate electricity by means of an ORC turbogenerator using low-temperature thermal water. The project is to improve the technical and economic situation of the existing industrial-scale geothermal project. (orig.) [Deutsch] Der Bericht beschreibt das Vorhaben der Marktgemeinde Altheim in Oberoesterreich, Strom mittels eines Organic-Rankine-Cycle-Turbogenerators unter Verwendung niedrig temperierten Thermalwassers zu produzieren. Ziel bzw. der Zweck des Projektes ist es, die technische und wirtschaftliche Situation der bestehenden Grossthermieanlage zu verbessern. (orig.)

  20. Organic Rankine-Cycle Power Systems Working Fluids Study: Topical report No. 3, 2-methylpyridine/water

    Energy Technology Data Exchange (ETDEWEB)

    Cole, R.L.; Demirgian, J.C.; Allen, J.W.

    1987-09-01

    A mixture of 35 mole percent (mol %) 2-methylpyridine and 65 mol % water was tested at 575, 625, and 675/degree/F in a dynamic loop. Samples of the degraded fluid were chemically analyzed to determine the identities of major degradation products and the quantity of degradation. Computed degradation rates were found to be higher than those for Fluorinol 85 or toluene. For this reason (and other reasons, related to fluid handling), other fluids are recommended as the first choice for service in organic Rankine-cycle systems in preference to 2-methylpyridine/water. 7 refs., 39 figs., 39 tabs.

  1. Integrated working fluid-thermodynamic cycle design of organic Rankine cycle power systems for waste heat recovery

    DEFF Research Database (Denmark)

    Cignitti, Stefano; Andreasen, Jesper Graa; Haglind, Fredrik

    2017-01-01

    recovery. Inthis paper, an organic Rankine cycle process and its pure working fluid are designed simultaneously forwaste heat recovery of the exhaust gas from a marine diesel engine. This approach can overcome designissues caused by the high sensitivity between the fluid and cycle design variables...... the simultaneousdesign approach the optimum solution was found in 5.04 s, while a decomposed approach found thesame solution in 5.77 h. However, the decomposed approach provided insights on the correlationbetween the fluid and cycle design variables by analyzing all possible solutions. It was shown that thehigh...

  2. Design and development of an automotive propulsion system utilizing a Rankine cycle engine (water based fluid). Final report

    Energy Technology Data Exchange (ETDEWEB)

    Demler, R.L.

    1977-09-01

    Under EPA and ERDA sponsorship, SES successfully designed, fabricated and tested the first federally sponsored steam powered automobile. The automobile - referred to as the simulator - is a 1975 Dodge Monaco standard size passenger car with the SES preprototype Rankine cycle automotive propulsion system mounted in the engine compartment. In the latter half of 1975, the simulator successfully underwent test operations at the facilities of SES in Watertown, Massachusetts and demonstrated emission levels below those of the stringent federally established automotive requirements originally set for implementation by 1976. The demonstration was accomplished during testing over the Federal Driving Cycle on a Clayton chassis dynamometer. The design and performance of the vehicle are described.

  3. Experimental and thermodynamic analysis of a bottoming Organic Rankine Cycle (ORC) of gasoline engine using swash-plate expander

    OpenAIRE

    Galindo, José,; Ruiz Rosales, Santiago; Dolz Ruiz, Vicente; ROYO PASCUAL, LUCÍA; Haller, R.; Nicolas, B.; Glavatskaya, Y.

    2015-01-01

    This paper deals with the experimental testing of an Organic Rankine Cycle (ORC) integrate in a 2 liter turbocharged gasoline engine using ethanol as working fluid. The main components of the cycle are a boiler, a condenser, a pump and a swash-plate expander. Five engine operating points have been tested, they correspond to a nominal heat input into the boiler of 5, 12, 20, 25 and 30 kW. With the available bill of material based on prototypes, power balances and cycles efficiencies were estim...

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

    Science.gov (United States)

    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.

  5. Association between Cerebral Performance Category, Modified Rankin Scale, and discharge disposition after cardiac arrest.

    Science.gov (United States)

    Rittenberger, Jon C; Raina, Ketki; Holm, Margo B; Kim, Young Joo; Callaway, Clifton W

    2011-08-01

    Cerebral Performance Category (CPC), Modified Rankin Scale (mRS) and discharge disposition are commonly used to determine outcomes following cardiac arrest. This study tested the association between these outcome measures. Retrospective chart review of subjects who survived to hospital discharge between 1/1/2006 and 12/31/2009 was conducted. Charts were reviewed for outcomes (CPC, mRS, and discharge disposition). Discharge disposition was classified in 6 categories: home with no services, home with home healthcare, acute rehabilitation facility, skilled nursing facility, long term acute care facility, and hospice. Intra-and inter-rater reliabilities were calculated for outcome measures. Rates of "good outcome" (defined as a CPC of 1-2, mRS of 0-3, or discharge disposition to home or acute rehabilitation facility) were also determined. Kendall's tau correlation coefficients explored relationships among measures. A total of 211 charts were reviewed. Mean age was 60 years (SD 16), the majority (75%) were white males, in- and out-of hospital cardiac arrests were equally prevalent, and ventricular dysrhythmia was most common (N=109, 52%). Half of the subjects were comatose following resuscitation and 75 (35%) received therapeutic hypothermia. Inter-rater percentage agreement for CPC and mRS abstraction was 95.24% (kappa 0.89, pdefinition, 47 subjects (22%) using the mRS definition, and 129 subjects (61%) subjects using discharge disposition definition. There was fair relationship between the CPC and mRS (tau 0.43) and poor relationships between CPC and discharge disposition (tau 0.23) and between mRS and discharge disposition (tau 0.25). Determination of the CPC, mRS and discharge disposition at hospital discharge is reliable from chart review. These instruments provide widely differing estimates of "good outcome". Agreement between these measures ranges from poor to fair. A more nuanced outcome measure designed for the post-cardiac arrest population is needed

  6. Thermal energy storage for low grade heat in the organic Rankine cycle

    Science.gov (United States)

    Soda, Michael John

    Limits of efficiencies cause immense amounts of thermal energy in the form of waste heat to be vented to the atmosphere. Up to 60% of unrecovered waste heat is classified as low or ultra-low quality, making recovery difficult or inefficient. The organic Rankine cycle can be used to generate mechanical power and electricity from these low temperatures where other thermal cycles are impractical. A variety of organic working fluids are available to optimize the ORC for any target temperature range. San Diego State University has one such experimental ORC using R245fa, and has been experimenting with multiple expanders. One limitation of recovering waste heat is the sporadic or cyclical nature common to its production. This inconsistency makes sizing heat recovery ORC systems difficult for a variety of reasons including off-design-point efficiency loss, increased attrition from varying loads, unreliable outputs, and overall system costs. Thermal energy storage systems can address all of these issues by smoothing the thermal input to a constant and reliable level and providing back-up capacity for times when the thermal input is deactivated. Multiple types of thermal energy storage have been explored including sensible, latent, and thermochemical. Latent heat storage involves storing thermal energy in the reversible phase change of a phase change material, or PCM, and can have several advantages over other modalities including energy storage density, cost, simplicity, reliability, relatively constant temperature output, and temperature customizability. The largest obstacles to using latent heat storage include heat transfer rates, thermal cycling stability, and potentially corrosive PCMs. Targeting 86°C, the operating temperature of SDSU's experimental ORC, multiple potential materials were explored and tested as potential PCMs including Magnesium Chloride Hexahydrate (MgCl2˙6H2O), Magnesium Nitrate Hexahydrate (Mg(NO3)2˙6H 2O), montan wax, and carnauba wax. The

  7. A Burst Mode, Ultrahigh Temperature UF4 Vapor Core Reactor Rankine Cycle Space Power System Concept

    Science.gov (United States)

    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

  8. In vitro gastrointestinal digestion of pea protein isolate as a function of pH, food matrices, autoclaving, high-pressure and re-heat treatments

    OpenAIRE

    Laguna, Laura; PICOUET, Pierre; Guàrdia, M. Dolors; Renard, Catherine; Sarkar, Anwesha

    2017-01-01

    This study investigated the influence of pH and processing conditions (autoclave at 93 °C/13 min or high pressure processing (HPP) at 600 MPa/5 min without/with follow-up reheating at 80 °C/30 min) on the digestibility of pea protein isolate. Both aqueous solutions and real food matrices (apple and carrot purees) containing pea protein was examined at 37 °C. In vitro gastrointestinal digestion was followed using sodium dodecyl sulphate polyacrylamide gel electrophoresis, titrimetric technique...

  9. Symmetric and Asymmetric Reheating

    OpenAIRE

    Hardy, Edward; Unwin, James

    2017-01-01

    We study models in which the inflaton is coupled to two otherwise decoupled sectors, and the effect of preheating and related processes on their energy densities during the evolution of the universe. Over most of parameter space, preheating is not disrupted by the presence of extra sectors, and even comparatively weakly coupled sectors can get an order 1 fraction of the total energy at this time. If two sectors are both preheated, the high number densities could also lead to inflaton mediated...

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

    Science.gov (United States)

    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.

  11. An experimental analysis of flow boiling and pressure drop in a brazed plate heat exchanger for organic Rankine cycle power systems

    DEFF Research Database (Denmark)

    Desideri, Adriano; Zhang, Ji; Kærn, Martin Ryhl

    2017-01-01

    Organic Rankine cycle power systems for low quality waste heat recovery applications can play a major role in achieving targets of increasing industrial processes efficiency and thus reducing the emissions of greenhouse gases. Low capacity organic Rankine cycle systems are equipped with brazed...... and pressure drop during vaporization at typical temperatures for low quality waste heat recovery organic Rankine cycle systems are presented for the working fluids HFC-245fa and HFO-1233zd. The experiments were carried out at saturation temperatures of 100°C, 115°C and 130°C and inlet and outlet qualities...... plate heat exchangers which allows for efficient heat transfer with a compact design. Accurate heat transfer correlations characterizing these devices are required from the design phase to the development of model-based control strategies. In this paper, the experimental heat transfer coefficient...

  12. Strong reciprocity is not uncommon in the "wild".

    Science.gov (United States)

    Runciman, W G

    2012-02-01

    Guala is right to draw attention to the difficulty of extrapolating from the experimental evidence for weak or strong reciprocity to what is observed in the "wild." However, there may be more strong reciprocity in real-world communities than he allows for, as strikingly illustrated in the example of the Mafia.

  13. Reciprocity Counseling: A Behavioral Approach to Marital Discord

    Science.gov (United States)

    Naster, Barry J.

    1977-01-01

    Reciprocity counseling is a rapid reinforcement-based procedure developed for teaching marriage partners how to increase their individual happiness within their marital relationship. The major obstacle to implementing reciprocity techniques is convincing the partners to engage in the procedures, even if they feel these procedures appear contrived…

  14. Reciprocal Relationships between Math Self-Concept and Math Anxiety

    Science.gov (United States)

    Ahmed, Wondimu; Minnaert, Alexander; Kuyper, Hans; van der Werf, Greetje

    2012-01-01

    The present study examined the reciprocal relationships between self-concept and anxiety in mathematics. A sample of 495 grade 7 students (51% girls) completed self-report measures assessing self-concept and anxiety three times in a school year. Structural equation modeling was used to test a cross-lagged panel model of reciprocal effects between…

  15. Sex differences in the reciprocal behaviour of children with autism

    NARCIS (Netherlands)

    Backer van Ommeren, Tineke; Koot, Hans M; Scheeren, Anke M; Begeer, Sander

    2016-01-01

    Differences in the social limitations of girls compared to boys on the autism spectrum are still poorly understood. Impaired social-emotional reciprocity is a core diagnostic criterion for an autism spectrum disorder. This study compares sex differences in reciprocal behaviour in children with

  16. Instructional Guidance in Reciprocal Peer Tutoring With Task Cards

    Science.gov (United States)

    Iserbyt, Peter; Elen, Jan; Behets, Daniel

    2010-01-01

    This article addresses the issue of instructional guidance in reciprocal peer tutoring with task cards as learning tools. Eighty-six Kinesiology students (age 17-19 years) were randomized across four reciprocal peer tutoring settings, differing in quality and quantity of guidance, to learn Basic Life Support (BLS) with task cards. The separate and…

  17. On the general Dedekind sums and its reciprocity formula

    Indian Academy of Sciences (India)

    (Math. Sci.) Vol. 120, No. 1, February 2010, pp. 1–6. © Indian Academy of Sciences. On the general Dedekind sums and its reciprocity formula. YUAN YI ... Note. Using this method, we can also give a new proof for the reciprocity formula of the classical Dedekind sum. For general positive integers m and n, whether there ...

  18. Reciprocal altruism in rats: Why does it occur?

    Science.gov (United States)

    Zentall, Thomas R

    2016-03-01

    The finding of reciprocal altruism in rats does not explain how such behavior came to be. Attributing it to a genetic predisposition or basic learning processes may not be what the authors had in mind, but the alternative, cultural learning, seems even less plausible for rats and perhaps is not even the primary basis for reciprocal altruism in humans.

  19. Reciprocal Pronouns Binding within Psych-Verb Constructions

    Science.gov (United States)

    Epoge, Napoleon

    2015-01-01

    This paper aims at giving an analysis of certain syntactic peculiarities of reciprocal pronouns within verbs of psychological state, commonly known as psych-verbs. The analysis reveal that psych-verbs constructions have a peculiar property in that the binding conditions of reciprocal pronouns are satisfied in Experiencer-Subject (ES) psychverbs…

  20. Reciprocal Cost Allocation and Decision Making for Universities.

    Science.gov (United States)

    Metzger, Lawrence M.

    1994-01-01

    Examines the use of the reciprocal method as an alternative to more conventional methods of university service department cost allocation. This method can be used with software that is readily available and with already known data. Reciprocal cost allocation will provide appropriate allocation values for financial reporting and data for university…

  1. Using Excel's Matrix Operations to Facilitate Reciprocal Cost Allocations

    Science.gov (United States)

    Leese, Wallace R.; Kizirian, Tim

    2009-01-01

    The reciprocal method of service department cost allocation requires linear equations to be solved simultaneously. These computations are often so complex as to cause the abandonment of the reciprocal method in favor of the less sophisticated direct or step-down methods. Here is a short example demonstrating how Excel's sometimes unknown matrix…

  2. Reciprocity, social ties, and competition in markets for experience goods

    DEFF Research Database (Denmark)

    Huck, Steffen; Tyran, Jean-Robert

    2007-01-01

    Reciprocal customers may disproportionately improve the performance of markets for experience goods. Reciprocal customers reward (punish) firms for providing good (bad) quality by upholding (terminating) the customer relation. This may induce firms to provide good quality which, in turn, may indu...

  3. 77 FR 9837 - Airworthiness Directives; Lycoming Engines Reciprocating Engines

    Science.gov (United States)

    2012-02-21

    ...; AD 2012-03-07] RIN 2120-AA64 Airworthiness Directives; Lycoming Engines Reciprocating Engines AGENCY... airworthiness directive (AD) for certain Lycoming Engines reciprocating engines. This AD was prompted by a... carburetor with one eligible for installation. We are issuing this AD to prevent engine in-flight shutdown...

  4. Sex Differences in the Reciprocal Behaviour of Children with Autism

    Science.gov (United States)

    Backer van Ommeren, Tineke; Koot, Hans M.; Scheeren, Anke M.; Begeer, Sander

    2017-01-01

    Differences in the social limitations of girls compared to boys on the autism spectrum are still poorly understood. Impaired social-emotional reciprocity is a core diagnostic criterion for an autism spectrum disorder. This study compares sex differences in reciprocal behaviour in children with autism spectrum disorder (32 girls, 114 boys) and in…

  5. State Authorization Reciprocity Agreement: Participation and Access to Higher Education

    Science.gov (United States)

    Onwuameze, Nkechi

    2017-01-01

    The State Authorization Reciprocity Agreement initiative was launched in 2014 to provide a uniform standard for the regulation of distance education across states in the United States. The system established by the National Council for State Authorization Reciprocity Agreement (NC-SARA) allows willing post-secondary institutions to participate…

  6. Performance Evaluation of a Helical Coil Heat Exchanger Working under Supercritical Conditions in a Solar Organic Rankine Cycle Installation

    Directory of Open Access Journals (Sweden)

    Marija Lazova

    2016-06-01

    Full Text Available Worldwide interest in low grade heat valorization using organic Rankine cycle (ORC technologies has increased significantly. A new small-scale ORC with a net capacity of 3 kW was efficiently integrated with a concentrated solar power technology for electricity generation. The excess heat source from Photovoltaic (PV collectors with a maximum temperature of 100 °C was utilized through a supercritical heat exchanger that uses R-404A as working medium. By ensuring supercritical heat transfer leads to a better thermal match in the heat exchanger and improved overall cycle efficiency. A helical coil heat exchanger was designed by using heat transfer correlations from the literature. These heat transfer correlations were derived for different conditions than ORCs and their estimated uncertainty is ~20%. In order to account for the heat transfer correlation uncertainties this component was oversized by 20%. Next, a prototype was built and installed in an integrated concentrated photovoltaic/thermal (CPV/T/Rankine system. The results from the measurements show that for better estimation of the sizing of the heat exchanger a more accurate correlation is required in order to design an optimal configuration and thus employ cheaper components.

  7. A Co-Powered Biomass and Concentrated Solar Power Rankine Cycle Concept for Small Size Combined Heat and Power Generation

    Directory of Open Access Journals (Sweden)

    Eileen Tortora

    2013-03-01

    Full Text Available The present work investigates the matching of an advanced small scale Combined Heat and Power (CHP Rankine cycle plant with end-user thermal and electric load. The power plant consists of a concentrated solar power field co-powered by a biomass furnace to produce steam in a Rankine cycle, with a CHP configuration. A hotel was selected as the end user due to its high thermal to electric consumption ratio. The power plant design and its operation were modelled and investigated by adopting transient simulations with an hourly distribution. The study of the load matching of the proposed renewable power technology and the final user has been carried out by comparing two different load tracking scenarios, i.e., the thermal and the electric demands. As a result, the power output follows fairly well the given load curves, supplying, on a selected winter day, about 50 GJ/d of thermal energy and the 6 GJ/d of electric energy, with reduced energy dumps when matching the load.

  8. Reciprocal regulation of bone and energy metabolism.

    Science.gov (United States)

    Baldock, Paul

    2011-01-01

    The primary relationship affecting skeletal tissue involves the association between fat mass and bone mass. However, there is some complexity in this relationship that may be explained by endocrine and neural pathways representing direct, reciprocal signalling between fat and bone tissue. For example, leptin signalling can directly stimulate osteoblastic differentiation and osteoblast proliferation and mineralization, but it also has central signalling actions in that it decreases cancellous bone volume. A novel regulatory loop between bone and adipose tissue suggests that uncarboxylated osteocalcin may affect energy homeostasis and afford a pathway by which fat mass can be regulated by bone mass. The multilayered and complex signals between fat and bone tissue involve both direct and indirect pathways. The endocrinologic nature of these signals highlights an emerging trend in medicine: identification of organ-based endocrine signals. Copyright © 2011 S. Karger AG, Basel.

  9. Thermal Powered Reciprocating-Force Motor

    Science.gov (United States)

    Tatum, III, Paul F. (Inventor); McDow Elliott, Amelia (Inventor)

    2015-01-01

    A thermal-powered reciprocating-force motor includes a shutter switchable between a first position that passes solar energy and a second position that blocks solar energy. A shape memory alloy (SMA) actuator is coupled to the shutter to control switching thereof between the shutter's first and second position. The actuator is positioned with respect to the shutter such that (1) solar energy impinges on the SMA when the shutter is in its first position so that the SMA experiences contraction in length until the shutter is switched to its second position, and (2) solar energy is impeded from impingement on the SMA when the shutter is in its second position so that the SMA experiences extension in length. Elastic members coupled to the actuator apply a force to the SMA that aids in its extension in length until the shutter is switched to its first position.

  10. A classroom demonstration of reciprocal space

    Science.gov (United States)

    Hannibal Madsen, Morten; Høpfner, Louise; Rasmussen, Nina; Stolborg, Mikkel; Nygârd, Jesper; Feidenhans'l, Robert; Thomsen, Jan W.

    2013-04-01

    An array of nanowires and a laser pointer are used for a simple visualization of two-dimensional reciprocal space. The experiment can be performed without any preparation and in any classroom. It aids the teaching of scattering experiments, and illustrates the underlying principles of electron, x-ray, and neutron scattering. A detailed study of the diffraction pattern was performed by mounting the sample with nanowires on a stage designed for x-ray scattering. The setup is well suited for undergraduate students, who get training in sample alignment in a small lab instead of at a large-scale facility. The exact positions of the diffraction spots are calculated and monitored experimentally for a 360° rotation of the sample. By fitting to this set of images, it is possible to determine the lattice vectors of the artificial crystal with an uncertainty of less than 1%.

  11. Sleep and exercise: a reciprocal issue?

    Science.gov (United States)

    Chennaoui, Mounir; Arnal, Pierrick J; Sauvet, Fabien; Léger, Damien

    2015-04-01

    Sleep and exercise influence each other through complex, bilateral interactions that involve multiple physiological and psychological pathways. Physical activity is usually considered as beneficial in aiding sleep although this link may be subject to multiple moderating factors such as sex, age, fitness level, sleep quality and the characteristics of the exercise (intensity, duration, time of day, environment). It is therefore vital to improve knowledge in fundamental physiology in order to understand the benefits of exercise on the quantity and quality of sleep in healthy subjects and patients. Conversely, sleep disturbances could also impair a person's cognitive performance or their capacity for exercise and increase the risk of exercise-induced injuries either during extreme and/or prolonged exercise or during team sports. This review aims to describe the reciprocal fundamental physiological effects linking sleep and exercise in order to improve the pertinent use of exercise in sleep medicine and prevent sleep disorders in sportsmen. Copyright © 2014 Elsevier Ltd. All rights reserved.

  12. Comprehensive model of a hermetic reciprocating compressor

    Science.gov (United States)

    Yang, B.; Ziviani, D.; Groll, E. A.

    2017-08-01

    A comprehensive simulation model is presented to predict the performance of a hermetic reciprocating compressor and to reveal the underlying mechanisms when the compressor is running. The presented model is composed of sub-models simulating the in-cylinder compression process, piston ring/journal bearing frictional power loss, single phase induction motor and the overall compressor energy balance among different compressor components. The valve model, leakage through piston ring model and in-cylinder heat transfer model are also incorporated into the in-cylinder compression process model. A numerical algorithm solving the model is introduced. The predicted results of the compressor mass flow rate and input power consumption are compared to the published compressor map values. Future work will focus on detailed experimental validation of the model and parametric studies investigating the effects of structural parameters, including the stroke-to-bore ratio, on the compressor performance.

  13. Does food sharing in vampire bats demonstrate reciprocity?

    Science.gov (United States)

    Carter, Gerald; Wilkinson, Gerald

    2013-01-01

    Claims of reciprocity (or reciprocal altruism) in animal societies often ignite controversy because authors disagree over definitions, naturalistic studies tend to demonstrate correlation not causation, and controlled experiments often involve artificial conditions. Food sharing among common vampire bats has been a classic textbook example of reciprocity, but this conclusion has been contested by alternative explanations. Here, we review factors that predict food sharing in vampire bats based on previously published and unpublished data, validate previous published results with more precise relatedness estimates, and describe current evidence for and against alternative explanations for its evolutionary stability. Although correlational evidence indicates a role for both direct and indirect fitness benefits, unequivocally demonstrating reciprocity in vampire bats still requires testing if and how bats respond to non-reciprocation. PMID:24505498

  14. Rethinking natural altruism: simple reciprocal interactions trigger children's benevolence.

    Science.gov (United States)

    Cortes Barragan, Rodolfo; Dweck, Carol S

    2014-12-02

    A very simple reciprocal activity elicited high degrees of altruism in 1- and 2-y-old children, whereas friendly but nonreciprocal activity yielded little subsequent altruism. In a second study, reciprocity with one adult led 1- and 2-y-olds to provide help to a new person. These results question the current dominant claim that social experiences cannot account for early occurring altruistic behavior. A third study, with preschool-age children, showed that subtle reciprocal cues remain potent elicitors of altruism, whereas a fourth study with preschoolers showed that even a brief reciprocal experience fostered children's expectation of altruism from others. Collectively, the studies suggest that simple reciprocal interactions are a potent trigger of altruism for young children, and that these interactions lead children to believe that their relationships are characterized by mutual care and commitment.

  15. Energetic and exergetic analysis of Rankine cycles for solar power plants with parabolic trough and thermal storage

    Directory of Open Access Journals (Sweden)

    Cenuşă Victor-Eduard

    2016-01-01

    Full Text Available The paper analyzes the “secondary” circuit (for thermodynamic conversion of a Concentrated Solar Power (CSP plant with thermodynamic cycle, whose mirrors field supplies a thermal power, averaged over a sunny day, of about 100 MW heat. We study the case of parabolic trough solar collector using silicone oil in the “primary” circuit, which limits the peak temperature below 400 °C. The “primary” circuit uses thermal storage, allowing a delay between the power generation in rapport with the solar energy capture. We choose a water-steam cycle, type Hirn. For increasing its efficiency, it has regenerative feed water preheating and steam reheating. We compared, energetic and exergetic, two types of cycles, using a numerical model with iterative structure, developed by the authors. The results showed that the simplified design achieves practically the same thermodynamic performances with the advanced one.

  16. Low Latency Digit-Recurrence Reciprocal and Square-Root Reciprocal Algorithm and Architecture

    DEFF Research Database (Denmark)

    Antelo, Elisardo; Lang, Tomas; Montuschi, Paolo

    2005-01-01

    The reciprocal and square-root reciprocal operations are important in several applications. For these operations, we present algorithms that combine a digit-by-digit module and one iteration of a quadratic-convergence approximation. The latter is implemented by a digit-recurrence, which uses...... the digits produced by the digit-by-digit part. In this way, both parts execute in an overlapped manner, so that the total number of cycles is about half of the number that would be required by the digit-by-digit part alone. Because of the approximation, correct rounding of the result cannot be obtained...... directly in all cases; we propose a variable-time implementation that produces the correctly rounded result with a small average overhead. Radix-4 implementations are described and have been synthesized. They achieve the same cycle time as the standard digit-by-digit implementation, resulting in a speed...

  17. 77 FR 60341 - National Emission Standards for Hazardous Air Pollutants for Reciprocating Internal Combustion...

    Science.gov (United States)

    2012-10-03

    ... Emission Standards for Hazardous Air Pollutants for Stationary Reciprocating Internal Combustion Engines to..., ``National Emission Standards for Hazardous Air Pollutants for Reciprocating Internal Combustion Engines; New... pollutants (NESHAP) for stationary reciprocating internal combustion engines (RICE), as well as other...

  18. BLAST: a digital computer program for the dynamic simulation of the high temperature gas cooled reactor reheater-steam generator module

    Energy Technology Data Exchange (ETDEWEB)

    Hedrick, R.A.; Cleveland, J.C.

    1976-06-24

    BLAST simulates the high temperature gas cooled reactor reheater-steam generator module with a multi-node, fixed boundary, homogenous flow model. The time dependent conservation of energy, mass, and momentum equations are solved by an implicit integration technique. The code contains equation of state formulations for both helium and water as well as heat transfer and friction factor correlations. Normal operational transients and more severe transients such as those resulting in low and/or reverse flow can be simulated. The code calculates helium and water temperature, pressure, flow rate, and tube bulk and wall temperatures at various points within the reheater-steam generator module during the transients. BLAST predictions will be compared with dynamic test results obtained from the Fort St. Vrain reactor owned by Public Service of Colorado, and, based on these comparisons, appropriate improvements will be made in BLAST. BLAST is written in FORTRAN IV for the IBM 360/91 computer at the Oak Ridge National Laboratory.

  19. The evolution of generalized reciprocity on social interaction networks.

    Science.gov (United States)

    van Doorn, Gerrit Sander; Taborsky, Michael

    2012-03-01

    Generalized reciprocity (help anyone, if helped by someone) is a minimal strategy capable of supporting cooperation between unrelated individuals. Its simplicity makes it an attractive model to explain the evolution of reciprocal altruism in animals that lack the information or cognitive skills needed for other types of reciprocity. Yet, generalized reciprocity is anonymous and thus defenseless against exploitation by defectors. Recognizing that animals hardly ever interact randomly, we investigate whether social network structure can mitigate this vulnerability. Our results show that heterogeneous interaction patterns strongly support the evolution of generalized reciprocity. The future probability of being rewarded for an altruistic act is inversely proportional to the average connectivity of the social network when cooperators are rare. Accordingly, sparse networks are conducive to the invasion of reciprocal altruism. Moreover, the evolutionary stability of cooperation is enhanced by a modular network structure. Communities of reciprocal altruists are protected against exploitation, because modularity increases the mean access time, that is, the average number of steps that it takes for a random walk on the network to reach a defector. Sparseness and community structure are characteristic properties of vertebrate social interaction patterns, as illustrated by network data from natural populations ranging from fish to primates. © 2011 The Author(s). Evolution© 2011 The Society for the Study of Evolution.

  20. Clustering in large networks does not promote upstream reciprocity.

    Directory of Open Access Journals (Sweden)

    Naoki Masuda

    Full Text Available Upstream reciprocity (also called generalized reciprocity is a putative mechanism for cooperation in social dilemma situations with which players help others when they are helped by somebody else. It is a type of indirect reciprocity. Although upstream reciprocity is often observed in experiments, most theories suggest that it is operative only when players form short cycles such as triangles, implying a small population size, or when it is combined with other mechanisms that promote cooperation on their own. An expectation is that real social networks, which are known to be full of triangles and other short cycles, may accommodate upstream reciprocity. In this study, I extend the upstream reciprocity game proposed for a directed cycle by Boyd and Richerson to the case of general networks. The model is not evolutionary and concerns the conditions under which the unanimity of cooperative players is a Nash equilibrium. I show that an abundance of triangles or other short cycles in a network does little to promote upstream reciprocity. Cooperation is less likely for a larger population size even if triangles are abundant in the network. In addition, in contrast to the results for evolutionary social dilemma games on networks, scale-free networks lead to less cooperation than networks with a homogeneous degree distribution.

  1. The Role of Friendship Reciprocity in University Freshmen's Alcohol Consumption.

    Science.gov (United States)

    Giese, Helge; Stok, F Marijn; Renner, Britta

    2017-07-01

    The similarity of friends in the frequency and quantity of alcohol consumption is explored. During their first semester, 57 psychology freshmen indicated weekly drinking frequency and quantity and nominated the three peers of this group they liked most. These nominations were then used to derive the weekly alcohol consumption of friends that either did or did not reciprocate a nomination. Multilevel modeling of weekly variations showed that individuals' drinking frequency was similar to peers who reciprocated a friendship (b = 0.15, p = .001), but not to non-reciprocating peers (b = -0.01, p = .720). In contrast, weekly variation in quantity of individual students' drinking was similar to both reciprocating (b = 0.11, p = .018) and non-reciprocating peers' drinking (b = 0.10, p = .014). Yet across all weeks, quantity tended only to be similar to non-reciprocating peers (b = 0.49, p = .020). Freshmen might spend drinking time with peers who reciprocate a friendship, but are similar regarding the quantity of drinks consumed to all people they find interesting. Thus, alcohol consumption is used strategically for social purposes. This social purpose should also be acknowledged in alcohol-reduction interventions. © 2017 The International Association of Applied Psychology.

  2. Near optimal graphene terahertz non-reciprocal isolator

    Science.gov (United States)

    Tamagnone, Michele; Moldovan, Clara; Poumirol, Jean-Marie; Kuzmenko, Alexey B.; Ionescu, Adrian M.; Mosig, Juan R.; Perruisseau-Carrier, Julien

    2016-04-01

    Isolators, or optical diodes, are devices enabling unidirectional light propagation by using non-reciprocal optical materials, namely materials able to break Lorentz reciprocity. The realization of isolators at terahertz frequencies is a very important open challenge made difficult by the intrinsically lossy propagation of terahertz radiation in current non-reciprocal materials. Here we report the design, fabrication and measurement of a terahertz non-reciprocal isolator for circularly polarized waves based on magnetostatically biased monolayer graphene, operating in reflection. The device exploits the non-reciprocal optical conductivity of graphene and, in spite of its simple design, it exhibits almost 20 dB of isolation and only 7.5 dB of insertion loss at 2.9 THz. Operation with linearly polarized light can be achieved using quarter-wave plates as polarization converters. These results demonstrate the superiority of graphene with respect to currently used terahertz non-reciprocal materials and pave the way to a novel class of optimal non-reciprocal devices.

  3. High-Resolution Reciprocal Space Mapping for Characterizing Deformation Structures

    DEFF Research Database (Denmark)

    Pantleon, Wolfgang; Wejdemann, Christian; Jakobsen, Bo

    2014-01-01

    With high-angular resolution three-dimensional X-ray diffraction (3DXRD), quantitative information is gained about dislocation structures in individual grains in the bulk of a macroscopic specimen by acquiring reciprocal space maps. In high-resolution 3D reciprocal space maps of tensile...... dynamics is followed in situ during varying loading conditions by reciprocal space mapping: during uninterrupted tensile deformation, formation of subgrains is observed concurrently with broadening of Bragg reflections shortly after the onset of plastic deformation. When the traction is terminated, stress...

  4. A 1.5 GFLOPS Reciprocal Unit for Computer Graphics

    DEFF Research Database (Denmark)

    Nannarelli, Alberto; Rasmussen, Morten Sleth; Stuart, Matthias Bo

    2006-01-01

    The reciprocal operation 1/d is a frequent operation performed in graphics processors (GPUs). In this work, we present the design of a radix-16 reciprocal unit based on the algorithm combining the traditional digit-by-digit algorithm and the approximation of the reciprocal by one Newton......-Raphson iteration. We design a fully pipelined single-precision unit to be used in GPUs. The results of the implementation show that the proposed unit can sustain a higher throughput than that of a unit implementing the normal Newton-Raphson approximation, and its area is smaller....

  5. Break of reciprocity principle due to localized nonlinearities in concrete.

    Science.gov (United States)

    Scalerandi, M; Bruno, C L E; Gliozzi, A S; Bocca, P G

    2012-08-01

    The effects of localized nonlinearities on the reciprocity principle in the context of ultrasounds and nonlinear elasticity are discussed in this paper. Experiments will be presented to prove that a localized crack in a concrete beam causes a break of reciprocity in the ultrasonic response to a mechanical excitation. The link between non-reciprocity and asymmetry in the nonlinear response will be demonstrated and discussed as a tool for NonDestructive Evaluation. Copyright © 2012 Elsevier B.V. All rights reserved.

  6. Verifying of reciprocal relations for nonlinear quadripole in unsteady mode

    Science.gov (United States)

    Bardin, Alexey; Ignatjev, Vyacheslav; Orlov, Andrey; Perchenko, Sergey

    This paper deals with experimental verification of reciprocal relations of nonlinear quadripole for unsteady mode in external magnetic field. We find out transients of measured voltages in the quadripole after current switch. These transients are caused by changing of current-voltage characteristics (CVC) of quadripole. We propose the reciprocal relations for linear part of full resistance matrix and its experimental verification method based on algorithm of separation of resistance matrix linear part. It is shown that the proposed reciprocal relations are valid with 10-3 relatively accuracy even for non-stationary case in external magnetic field.

  7. Selection of cooling fluid for an organic Rankine cycle unit recovering heat on a container ship sailing in the Arctic region

    DEFF Research Database (Denmark)

    Suárez de la Fuente, Santiago; Larsen, Ulrik; Pierobon, Leonardo

    2017-01-01

    air as coolant. This paper explores the use of two different coolants, air and seawater, for an organic Rankine cycle (ORC) unit using the available waste heat in the scavenge air system of a container ship navigating in Arctic Circle. Using a two-step single objective optimisation process, detailed...

  8. Performance Evaluation of a HP/ORC (Heat Pump/Organic Rankine Cycle) System with Optimal Control of Sensible Thermal Storage

    DEFF Research Database (Denmark)

    Carmo, Carolina; Nielsen, Mads P.; Elmegaard, Brian

    2016-01-01

    come to contribute to the integration of intermittent renewables.This paper describes an innovative concept that consists of the addition of an Organic Rankine Cycle (ORC) toa combined solar system coupled to a ground-source heat pump (HP) in a single-family building. The ORC enables the use of solar...

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

    Science.gov (United States)

    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.

  10. Design and optimisation of organic Rankine cycles for waste heat recovery in marine applications using the principles of natural selection

    DEFF Research Database (Denmark)

    Larsen, Ulrik; Pierobon, Leonardo; Haglind, Fredrik

    2013-01-01

    , boundary conditions, hazard levels and environmental concerns. A generally applicable methodology, based on the principles of natural selection, is presented and used to determine the optimum working fluid, boiler pressure and Rankine cycle process layout for scenarios related to marine engine heat......Power cycles using alternative working fluids are currently receiving significant attention. Selection of working fluid among many candidates is a key topic and guidelines have been presented. A general problem is that the selection is based on numerous criteria, such as thermodynamic performance...... recovery. Included in the solution domain are 109 fluids in sub and supercritical processes, and the process is adapted to the properties of the individual fluid. The efficiency losses caused by imposing process constraints are investigated to help propose a suitable process layout. Hydrocarbon dry type...

  11. Improving the efficiency of heat supply systems on the basis of plants operating on organic Rankine cycle

    Science.gov (United States)

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

    2017-11-01

    Results of experimental and analytical studies of the plant main element – plant turbomachine (turbo-expander) operating on organic Rankine cycle were obtained for facilities of the heat supply systems of small-scale power generation. At simultaneous mathematical modeling and experimental studies it was found that the best working medium to be used in the turbomachines of these plants is Freon R245fa which has the most suitable calorimetric properties to be used in the cycle. The mathematical model of gas flow in the turbomachine was developed. The main engineering dependencies to calculate the optimal design parameters of the turbomachine were obtained. The engineering problems of providing the minimum axial size of the turbomachine impeller were solved and the main design elements were unified.

  12. Thermal-Economic Modularization of Small, Organic Rankine Cycle Power Plants for Mid-Enthalpy Geothermal Fields

    Directory of Open Access Journals (Sweden)

    Yodha Y. Nusiaputra

    2014-07-01

    Full Text Available The costs of the surface infrastructure in mid-enthalpy geothermal power systems, especially in remote areas, could be reduced by using small, modular Organic Rankine Cycle (ORC power plants. Thermal-economic criteria have been devised to standardize ORC plant dimensions for such applications. We designed a modular ORC to utilize various wellhead temperatures (120–170 °C, mass flow rates and ambient temperatures (−10–40 °C. A control strategy was developed using steady-state optimization, in order to maximize net power production at off-design conditions. Optimum component sizes were determined using specific investment cost (SIC minimization and mean cashflow (MCF maximization for three different climate scenarios. Minimizing SIC did not yield significant benefits, but MCF proved to be a much better optimization function.

  13. Experimental study on Rankine cycle evaporator efficiency intended for exhaust waste heat recovery of a diesel engine

    Directory of Open Access Journals (Sweden)

    Milkov Nikolay

    2017-01-01

    Full Text Available The paper pressents an experimental study of Rankine cycle evaporator efficiency. Water was chosen as the working fluid in the system. The experimental test was conducted on a test bench equipped with a burner charged by compressed fresh air. Generated exhaust gases parameters were previously determined over the diesel engine operating range (28 engine operating points were studied. For each test point the working fluid parameters (flow rate and evaporating pressure were varied. Thus, the enthalpy flow through the heat exchanger was determined. Heat exchanger was designed as 23 helical tubes are inserted. On the basis of the results, it was found out that efficiency varies from 25 % to 51,9 %. The optimal working fluid pressure is 20 bar at most of the operating points while the optimum fluid mass flow rate varies from 2 g/s to 10 g/s.

  14. Energy performance and economic evaluation of heat pump/organic rankine cycle system with sensible thermal storage

    DEFF Research Database (Denmark)

    Carmo, Carolina; Dumont, Olivier; Nielsen, Mads Pagh

    2016-01-01

    that consists of a ground-source heat pump with possibility of reversing operation as an ORC power cycle combined with solar heating in a single-family building is introduced. The ORC mode enables the use of solar energy in periods of no heat energy demand and reverses the heat pump cycle to supply electrical......-life conditions knowledge, the paper considers two different sensible energy storage (TES) configurations for the reversible heat pump/organic Rankine cycle (HP/ORC) system: a buffer tank for both space heating and domestic hot water and a hot water storage tank used exclusively for domestic hot water......The interaction between electrical and thermal energy demands represent a potential area for balancing supply and demand that could contribute to the integration of intermittent renewables in energy systems. To enable the interaction between thermal and electric energy, an innovative concept...

  15. Energy Performance and Economic Evaluation of Heat Pump/Organic Rankine Cycle System with Sensible Thermal Storage

    DEFF Research Database (Denmark)

    Carmo, C.; Dumont, O.; Nielsen, M. P.

    2016-01-01

    that consists of a ground-source heat pump with possibility of reversing operation as an ORC power cycle combined with solar heating in a single-family building is introduced. The ORC mode enables the use of solar energy in periods of no heat energy demand and reverses the heat pump cycle to supply electrical......-life conditions knowledge, the paper considers two different sensible energy storage (TES) configurations for the reversible heat pump/organic Rankine cycle (HP/ORC) system: a buffer tank for both space heating and domestic hot water and a hot water storage tank used exclusively for domestic hot water......The interaction between electrical and thermal energy demands represent a potential area for balancing supply and demand that could contribute to the integration of intermittent renewables in energy systems. To enable the interaction between thermal and electric energy, an innovative concept...

  16. Cogenerative Performance of a Wind − Gas Turbine − Organic Rankine Cycle Integrated System for Offshore Applications

    DEFF Research Database (Denmark)

    Bianchi, Michele; Branchini, Lisa; De Pascale, Andrea

    2016-01-01

    Gas Turbines (GT) are widely used for power generationin offshore oil and gas facilities, due to their high reliability,compactness and dynamic response capabilities. Small heavyduty and aeroderivative units in multiple arrangements aretypically used to offer larger load flexibility......, but limitedefficiency of such machines is the main drawback. A solutionto enhance the system performance, also in Combined Heat andPower (CHP) arrangement, is the implementation of OrganicRankine Cycle (ORC) systems at the bottom of the gas turbines.Moreover, the resulting GT-ORC combined cycle could befurther...... a 10MW offshorewind farm and three gas turbines rated for 16:5MW, eachone coupled with an 4:5MW ORC module. The ORC mainparameters are observed under different wind power fluctuations.Due to the non-programmable availability of wind and powerdemand, the part-load and dynamic characteristics...

  17. Study on the Characteristics of Expander Power Output Used for Offsetting Pumping Work Consumption in Organic Rankine Cycles

    Directory of Open Access Journals (Sweden)

    Yu-Ting Wu

    2014-07-01

    Full Text Available The circulation pump in an organic Rankine cycle (ORC increases the pressure of the liquid working fluid from low condensing pressure to high evaporating pressure, and the expander utilizes the pressure difference to generate work. A portion of the expander output power is used to offset the consumed pumping work, and the rest of the expander power is exactly the net work produced by the ORC system. Because of the relatively great theoretical pumping work and very low efficiency of the circulation pump reported in previous papers, the characteristics of the expander power used for offsetting the pumping work need serious consideration. In particular, the present work examines those characteristics. It is found that the characteristics of the expander power used for offsetting the pumping work are satisfactory only under the condition that the working fluid absorbs sufficient heat in the evaporator and its specific volume at the evaporator outlet is larger than or equal to a threshold value.

  18. 10-75-kWe-reactor-powered organic Rankine-cycle electric power systems (ORCEPS) study. Final technical report

    Energy Technology Data Exchange (ETDEWEB)

    1977-03-30

    This 10-75 kW(e) Reactor-ORCEPS study was concerned with the evaluation of several organic Rankine cycle energy conversion systems which utilized a /sup 235/U-ZrH reactor as a heat source. A liquid metal (NaK) loop employing a thermoelectric converter-powered EM pump was used to transfer the reactor energy to the organic working fluid. At moderate peak cycle temperatures (750/sup 0/F), power conversion unit cycle efficiencies of up to 25% and overall efficiencies of 20% can be obtained. The required operating life of seven years should be readily achievable. The CP-25 (toluene) working fluid cycle was found to provide the highest performance levels at the lowest system weights. Specific weights varies from 100 to 50 lb/kW(e) over the power level range 10 to 75 kW(e). (DLC)

  19. Structural optimisation of a high speed Organic Rankine Cycle generator using a genetic algorithm and a finite element method

    Energy Technology Data Exchange (ETDEWEB)

    Palko, S. [Machines Division, ABB industry Oy, Helsinki (Finland)

    1997-12-31

    The aim in this work is to design a 250 kW high speed asynchronous generator using a genetic algorithm and a finite element method for Organic Rankine Cycle. The characteristics of the induction motors are evaluated using two-dimensional finite element method (FEM) The movement of the rotor and the non-linearity of the iron is included. In numerical field problems it is possible to find several local extreme for an optimisation problem, and therefore the algorithm has to be capable of determining relevant changes, and to avoid trapping to a local minimum. In this work the electromagnetic (EM) losses at the rated point are minimised. The optimisation includes the air gap region. Parallel computing is applied to speed up optimisation. (orig.) 2 refs.

  20. Optimization of Cycle and Expander Design of an Organic Rankine Cycle Unit using Multi-Component Working Fluids

    DEFF Research Database (Denmark)

    Meroni, Andrea; Andreasen, Jesper Graa; Pierobon, Leonardo

    2016-01-01

    for an organic Rankine cycle unit utilizing waste heat from low temperature heat sources. The study addresses a case where the minimum temperature of the heat source is constrained and a case where no constraint is imposed. The former case is the wasteheat recovery from jacket cooling water of a marine diesel...... engine onboard a large ship, and the latter is representative of a low-temperature geothermal, solar or waste heat recovery application. Multi-component working fluids are investigated, as they allow improving the match between the temperature pro-files in the heat exchangers and, consequently, reducing...... the irreversibility in the ORC system. This work considers mixtures of R245fa/pentane and propane/isobutane. The use of multi-component working fluids typically results in increased heat transfer areas and different expander designs compared to purefluids. In order to properly account for turbine performance...

  1. Systematic Methods for Working Fluid Selection and the Design, Integration and Control of Organic Rankine Cycles—A Review

    Directory of Open Access Journals (Sweden)

    Patrick Linke

    2015-05-01

    Full Text Available Efficient power generation from low to medium grade heat is an important challenge to be addressed to ensure a sustainable energy future. Organic Rankine Cycles (ORCs constitute an important enabling technology and their research and development has emerged as a very active research field over the past decade. Particular focus areas include working fluid selection and cycle design to achieve efficient heat to power conversions for diverse hot fluid streams associated with geothermal, solar or waste heat sources. Recently, a number of approaches have been developed that address the systematic selection of efficient working fluids as well as the design, integration and control of ORCs. This paper presents a review of emerging approaches with a particular emphasis on computer-aided design methods.

  2. Steam by-pass reciprocating rod pump

    Energy Technology Data Exchange (ETDEWEB)

    Waterhouse, B. [Weatherford, Edmonton, AB (Canada)

    2008-07-01

    This article presented the design details of Weatherford's steam by-pass reciprocating rod rod pump which was designed to work under specific well conditions and individual applications, including Imperial Oil's Cold Lake bitumen recovery project located 230 km northeast of Edmonton, Alberta. Imperial Oil uses a cyclic steam stimulation (CSS) process to enhance bitumen recovery from the Clearwater oil sand reservoir. A typical wellbore reach can be up to 700 m and 80 degrees deviation at a target depth of 455 m TVD. These long well bore reaches along with high bottomhole angles and high produced fluid viscosities complicate the design of the artificial lift, which is essentially a modified conventional API pump. The hold-down section is a friction ring design incorporating stainless steel friction rings to provide positive holding force. The steam by-pass coupling is a reduced-diameter tube fitting between the API pump and the friction ring hold-down section. Three stages of the Imperial Cold Lake operation were described, namely the steam injection stage, soak phase stage and production stage. Typically, the steam by-pass pump is suspended in the tubing for the entire cycle. This presentation reviewed the operating steps of the pump, whose average run time in the field is about 15 months, depending on the potential for scaling or sand influx. tab., figs.

  3. Improving reading comprehension through Reciprocal Teaching Method

    Directory of Open Access Journals (Sweden)

    Endang Komariah

    2015-10-01

    Full Text Available This study is aimed at discovering the benefits of the Reciprocal Teaching Method (RTM in the reading classroom, finding out the achievements of students after four comprehension training sessions of using RTM, and exploring the perceptions of students on the use of RTM. This method uses four comprehension strategies: predicting, questioning, clarifying, and summarizing, to help learners monitor their development of reading comprehension by themselves. Students work in groups of four or five and the members are divided into five roles which are the leader, predictor, clarifier, questioner, and summarizer. The subjects were 24 students from the twelfth grade at a high school in Banda Aceh. Observations, tests, documents and interviews were collected to get the data. The results showed that the students were more active and productive in the reading classroom after RTM sessions and their reading proficiency improved. They learnt how to apply several of the strategies from RTM while reading. The results also showed that they preferred this method for teaching-learning reading compared to the conventional one. Therefore, teachers are suggested to consider using this method for teaching reading that instils the students on how to apply the four comprehension strategies used in reading.

  4. Memory-n strategies of direct reciprocity.

    Science.gov (United States)

    Hilbe, Christian; Martinez-Vaquero, Luis A; Chatterjee, Krishnendu; Nowak, Martin A

    2017-05-02

    Humans routinely use conditionally cooperative strategies when interacting in repeated social dilemmas. They are more likely to cooperate if others cooperated before, and are ready to retaliate if others defected. To capture the emergence of reciprocity, most previous models consider subjects who can only choose from a restricted set of representative strategies, or who react to the outcome of the very last round only. As players memorize more rounds, the dimension of the strategy space increases exponentially. This increasing computational complexity renders simulations for individuals with higher cognitive abilities infeasible, especially if multiplayer interactions are taken into account. Here, we take an axiomatic approach instead. We propose several properties that a robust cooperative strategy for a repeated multiplayer dilemma should have. These properties naturally lead to a unique class of cooperative strategies, which contains the classical Win-Stay Lose-Shift rule as a special case. A comprehensive numerical analysis for the prisoner's dilemma and for the public goods game suggests that strategies of this class readily evolve across various memory-n spaces. Our results reveal that successful strategies depend not only on how cooperative others were in the past but also on the respective context of cooperation.

  5. Reciprocity in International Affairs: An Analysis of Nigeria/South ...

    African Journals Online (AJOL)

    . The paper recommended among other things that the two countries need to cooperate more for their own sakes and for the sake of the African continent. Key Words: Reciprocity, International, Affairs, Diplomatic face-off, Nigeria, South Africa.

  6. EFRC guidelines for vibrations in reciprocating compressor systems

    NARCIS (Netherlands)

    Eijk, A.

    2008-01-01

    One of the disadvantages of a reciprocating compressor is that it generates pulsations and vibrations, which, without limitation and proper attention during design, manufacturing, installation and operation, can lead to fatigue failures, inefficiency, capacity limitations and unsafe situations. To

  7. 78 FR 59293 - Airworthiness Directives; Continental Motors, Inc. Reciprocating Engines

    Science.gov (United States)

    2013-09-26

    ... Motors, Inc. Reciprocating Engines AGENCY: Federal Aviation Administration (FAA), DOT. ACTION: Notice of... our proposed airworthiness directive (AD) for certain Continental Motors, Inc., engines with Airmotive... cylinder assemblies are marketed by Engine Components International Division. DATES: The comment period for...

  8. Research on networked manufacturing system for reciprocating pump industry

    Science.gov (United States)

    Wu, Yangdong; Qi, Guoning; Xie, Qingsheng; Lu, Yujun

    2005-12-01

    Networked manufacturing is a trend of reciprocating pump industry. According to the enterprises' requirement, the architecture of networked manufacturing system for reciprocating pump industry was proposed, which composed of infrastructure layer, system management layer, application service layer and user layer. Its main functions included product data management, ASP service, business management, and customer relationship management, its physics framework was a multi-tier internet-based model; the concept of ASP service integration was put forward and its process model was also established. As a result, a networked manufacturing system aimed at the characteristics of reciprocating pump industry was built. By implementing this system, reciprocating pump industry can obtain a new way to fully utilize their own resources and enhance the capabilities to respond to the global market quickly.

  9. The general chain transform and self-reciprocal functions

    Directory of Open Access Journals (Sweden)

    Cyril Nasim

    1985-01-01

    Full Text Available A theory of a generalized form of the chain transforms of order n is developed, and various properties of these are established including the Parseval relation. Most known cases of the standard theory are derived as special cases. Also a theory of self-reciprocal functions is given, based on these general chain transforms; and relations among various classes of self-reciprocal functions are established.

  10. Reciprocal cooperation in avian mobbing: playing nice pays.

    Science.gov (United States)

    Wheatcroft, David J; Price, Trevor D

    2008-08-01

    Unrelated passerine birds often join together while mobbing, a widespread antipredator behavior during which birds harass a predator. Although previous analyses concluded that mobbing could not have evolved via reciprocity, Krams and colleagues' field experiments show that birds preferentially join mobs with neighbors that have aided them previously, suggesting that these birds utilize reciprocity-based strategies involving individual recognition and recollection of previous interactions with others. This implies a level of sophistication in bird communities greater than had previously been realized.

  11. Reciprocality of Recombination Events That Rearrange the Chromosome

    OpenAIRE

    Mahan, M. J.; Roth, J. R.

    1988-01-01

    We describe a genetic system for studying the reciprocality of chromosomal recombination; all substrates and recombination functions involved are provided exclusively by the bacterial chromosome. The genetic system allows the recovery of both recombinant products from a single recombination event. The system was used to demonstrate the full reciprocality of three different types of recombination events: (1) intrachromosomal recombination between direct repeats, causing deletions; (2) intrachr...

  12. Reciprocity as a Key Concept for Social Media and Society

    OpenAIRE

    Seth C. Lewis

    2015-01-01

    The concept of reciprocity, particularly in the pro-social sense of mutually beneficial exchange, presents an opportunity befitting the start of a new journal on social media. Namely, how might a concept of social exchange help us understand a mediascape increasingly dominated by social exchange—where the sharing, receiving, and recirculating of information “gifts” is central to the very social and technical frameworks on which these media function? In essence, what might reciprocity, analyze...

  13. Square Root Variations of Reciprocal Graphing of Enzyme Kinetic Data.

    Science.gov (United States)

    Stutts, P; Fridovich, I

    1965-07-23

    A variation of the Lineweaver and Burk graph, in which the reciprocal of the square root of the initial reaction velocity is plotted as a function of the reciprocal of the substrate concentration, has been described in the literature and has subsequently been used as the basis of proposals of reaction mechanisms. The utility of this treatment of enzyme kinetic data is examined and has been found to be limited.

  14. Indirect reciprocity is sensitive to costs of information transfer

    OpenAIRE

    Shinsuke Suzuki; Hiromichi Kimura

    2013-01-01

    How natural selection can promote cooperative or altruistic behavior is a fundamental question in biological and social sciences. One of the persuasive mechanisms is "indirect reciprocity," working through reputation: cooperative behavior can prevail because the behavior builds the donor's good reputation and then s/he receives some reciprocal benefits from someone else in the community. However, an important piece missed in the previous studies is that the reputation-building process require...

  15. Bah humbug: Unexpected Christmas cards and the reciprocity norm.

    Science.gov (United States)

    Meier, Brian P

    2016-01-01

    The reciprocity norm refers to the expectation that people will help those who helped them. A well-known study revealed that the norm is strong with Christmas cards, with 20% of people reciprocating a Christmas card received from a stranger. I attempted to conceptually replicate and extend this effect. In Study 1, 755 participants received a Christmas card supposedly from a more- versus less-similar stranger. The reciprocation rate was unexpectedly low (2%), which did not allow for a test of a similarity effect. Two potential reasons for this low rate were examined in Study 2 in which 494 participants reported their likelihood of reciprocating a Christmas card from a stranger as well as their felt suspicions/threat about the card and their frequency of e-mail use. Reciprocation likelihood was negatively correlated with perceived threat/suspicion and e-mail use. It appears that reciprocating a gift from a stranger in offline settings may be less likely than expected.

  16. Preschool children's behavioral tendency toward social indirect reciprocity.

    Directory of Open Access Journals (Sweden)

    Mayuko Kato-Shimizu

    Full Text Available Social indirect reciprocity seems to be crucial in enabling large-scale cooperative networks among genetically unrelated individuals in humans. However, there are relatively few studies on social indirect reciprocity in children compared to adults. Investigating whether young children have a behavioral tendency toward social indirect reciprocity will help us understand how and when the fundamental ability to form cooperative relationships among adults is acquired. Using naturalistic observation at a nursery school, this study examined whether 5- to 6-year-olds show a behavioral tendency to engage in social indirect reciprocity in response to their peers' prosocial behavior toward a third party. The results revealed that bystander children tended to display prosocial behavior toward their peers more frequently after observing these peers' prosocial behavior toward third-party peers, compared with control situations; this suggests that 5- to 6-year-olds may have an essential behavioral tendency to establish social indirect reciprocity when interacting with peers in their daily lives. In addition, bystanders tended to display affiliative behavior after observing focal children's prosocial behavior. In other words, observing peers' prosocial behavior toward third-party peers evoked bystanders' positive emotions toward the helpers. Considering both the present results and previous findings, we speculate that in preschoolers, such positive emotions might mediate the increase in the bystander's prosocial behavior toward the helper. In addition, an intuitional emotional process plays an important role in the preschooler's behavioral tendency toward social indirect reciprocity in natural interactions with peers.

  17. Reciprocal Pronouns Binding within Psych-verb Constructions

    Directory of Open Access Journals (Sweden)

    Napoleon Epoge

    2015-04-01

    Full Text Available This paper aims at giving an analysis of certain syntactic peculiarities of reciprocal pronouns within verbs of psychological state, commonly known as psych-verbs. The analysis reveal that psych-verbs constructions have a peculiar property in that the binding conditions of reciprocal pronouns are satisfied in Experiencer-Subject (ES psych-verbs constructions but are not in the Experiencer-Object (EO at the surface level; though the latter constructions are grammatical. However, the paper argues that though binding conditions are not satisfied in EO psych-verb constructions at the surface level, they are satisfied in the deep structure (D-structure construction wherein the reciprocal pronoun, in the theme argument, is bound by a c-commanding Experiencer argument. By so doing, it satisfies binding condition A which holds that a reciprocal pronoun must be bound by an appropriate c-command antecedent. This analysis shows that reciprocal binding in Experiencer-Object psych-verb constructions, at the D-structure, does not reflect the linear order in the thematic hierarchy as proposed by Grimshaw (1990 and the psych-verb in EO D-structure construction is construed as one with two internal arguments. Keywords: antecedent, binding theory, D-structure, psych-verb, reciprocal pronoun, S-structure

  18. Operating results of Hekinan power station No. 3 unit with elevated reheat steam temperature 593[degree]C. Koon sainen joki ondo 593[degree]C Hekinan karyoku 3 goki no shiunten jisseki

    Energy Technology Data Exchange (ETDEWEB)

    Ohara, H. (Chubu Electric Power Co. Inc., Nagoya (Japan)); Ishimoto, R.; Kuwahara, M. (Ishikawajima-Harima Heavy Industries Co. Ltd., Tokyo (Japan)); Ichimura, T.; Minami, Y. (Mitsubishi Heavy Industries, Ltd., Tokyo (Japan))

    1994-05-15

    This paper introduces the Japan's first large-capacity coal fired thermal power plant that uses elevated reheat steam temperature of 593[degree]C as a commercial power plant. This unit is characterized by the high efficiency (adoption of titanium alloy 40-inch blades in the steam turbine and the reaction stage that has been designed by analyzing three-dimensional flows), high operational characteristics (achievement in high load fluctuation rate and improvement in actuation characteristics), and low pollution (suppressed NOx emission). Considerations given in adopting the high steam temperature conditions included the following: optimization in heat conduction arrangement of reheaters on the boiler side; adequate selection of high-temperature materials; measures against high-temperature corrosion and steam oxidization; assurance of reliability in accessories to the high-temperature components; discussions on the improved 12 Cr forged rotor material on the turbine side; and search of an appropriate medium-pressure turbine rotor cooling method and high-performance high-reliability reaction blades. Results exceeding the planned values were obtained on the plant efficiency, the turbine efficiency and the boiler efficiency. Good values were acquired on the reheated steam temperature control range as the static boiler characteristics and the temperature distribution in the reheater metal. Safety was identified in the steam turbine vibration characteristics. 7 refs., 17 figs., 3 tabs.

  19. Reciprocating clamp apparatus for thermoforming plastic containers

    Energy Technology Data Exchange (ETDEWEB)

    Beck, M.H.; Harry, I.L.; Krishnakumar, S.M.

    1984-03-06

    This relates to the forming of containers and like hollow articles from sheets or webs of thermoplastic material. Two webs or sheets are simultaneously acted upon by way of a forming apparatus which includes a reciprocating clamp first cooperable with one outer platen and then the other in sequence wherein, while a first web or sheet is being formed within a plurality of mold cavities to define a plurality of hollow articles such as containers, the other sheet or web may be stripped from its respective mold set and a new sheet or a new portion of a sheet or web may be advanced into position for molding. The forming apparatus may be constructed in a manner wherein the web portions which are to be formed may be billowed away from the mold cavities as an initial step in the stretching and orientation of the thermoplastic material. The thermoplastic material may be heated to the desired forming temperature using separate sets of rf electrodes so that only those portions of the thermoplastic material which are to be formed need be heated. Two sets of containers of different sizes may be formed from the webs or sheets, and then internested to form double wall containers wherein the walls may be formed of different materials and wherein the outer material may be a barrier material, or wherein the walls of the containers are spaced apart to form an insulated container. This abstract forms no part of the specification of this application and is not to be construed as limiting the claims of the application.

  20. Reciprocating flow-based centrifugal microfluidics mixer

    Science.gov (United States)

    Noroozi, Zahra; Kido, Horacio; Micic, Miodrag; Pan, Hansheng; Bartolome, Christian; Princevac, Marko; Zoval, Jim; Madou, Marc

    2009-07-01

    Proper mixing of reagents is of paramount importance for an efficient chemical reaction. While on a large scale there are many good solutions for quantitative mixing of reagents, as of today, efficient and inexpensive fluid mixing in the nanoliter and microliter volume range is still a challenge. Complete, i.e., quantitative mixing is of special importance in any small-scale analytical application because the scarcity of analytes and the low volume of the reagents demand efficient utilization of all available reaction components. In this paper we demonstrate the design and fabrication of a novel centrifugal force-based unit for fast mixing of fluids in the nanoliter to microliter volume range. The device consists of a number of chambers (including two loading chambers, one pressure chamber, and one mixing chamber) that are connected through a network of microchannels, and is made by bonding a slab of polydimethylsiloxane (PDMS) to a glass slide. The PDMS slab was cast using a SU-8 master mold fabricated by a two-level photolithography process. This microfluidic mixer exploits centrifugal force and pneumatic pressure to reciprocate the flow of fluid samples in order to minimize the amount of sample and the time of mixing. The process of mixing was monitored by utilizing the planar laser induced fluorescence (PLIF) technique. A time series of high resolution images of the mixing chamber were analyzed for the spatial distribution of light intensities as the two fluids (suspension of red fluorescent particles and water) mixed. Histograms of the fluorescent emissions within the mixing chamber during different stages of the mixing process were created to quantify the level of mixing of the mixing fluids. The results suggest that quantitative mixing was achieved in less than 3 min. This device can be employed as a stand alone mixing unit or may be integrated into a disk-based microfluidic system where, in addition to mixing, several other sample preparation steps may be

  1. Dataset of working conditions and thermo-economic performances for hybrid organic Rankine plants fed by solar and low-grade energy sources.

    Science.gov (United States)

    Scardigno, Domenico; Fanelli, Emanuele; Viggiano, Annarita; Braccio, Giacobbe; Magi, Vinicio

    2016-06-01

    This article provides the dataset of operating conditions of a hybrid organic Rankine plant generated by the optimization procedure employed in the research article "A genetic optimization of a hybrid organic Rankine plant for solar and low-grade energy sources" (Scardigno et al., 2015) [1]. The methodology used to obtain the data is described. The operating conditions are subdivided into two separate groups: feasible and unfeasible solutions. In both groups, the values of the design variables are given. Besides, the subset of feasible solutions is described in details, by providing the thermodynamic and economic performances, the temperatures at some characteristic sections of the thermodynamic cycle, the net power, the absorbed powers and the area of the heat exchange surfaces.

  2. Flow boiling heat transfer and pressure drop characteristics of R134a, R1234yf and R1234ze in a plate heat exchanger for organic Rankine cycle units

    DEFF Research Database (Denmark)

    Zhang, Ji; Desideri, Adriano; Kærn, Martin Ryhl

    2017-01-01

    . This paper is aimed at obtaining flow boiling heat transfer and pressure drop characteristics in a plate heat exchanger under the working conditions prevailing in the evaporator of organic Rankine cycle units. Two hydrofluoroolefins R1234yf and R1234ze, and one hydrofluorocarbon R134a, were selected......The optimal design of the evaporator is one of the key issues to improve the efficiency and economics of organic Rankine cycle units. The first step in studying the evaporator design is to understand the thermal-hydraulic performance of the working fluid in the evaporator of organic Rankine cycles......, respectively. The working conditions covered relatively high saturation temperatures (corresponding reduced pressures of 0.35-0.74), which are prevailing in organic Rankine cycles yet absent in the open literature. The experimental data were compared with existing correlations, and new correlations were...

  3. Optimization of Biomass-Fuelled Combined Cooling, Heating and Power (CCHP) Systems Integrated with Subcritical or Transcritical Organic Rankine Cycles (ORCs)

    OpenAIRE

    Daniel Maraver; Sylvain Quoilin; Javier Royo

    2014-01-01

    This work is focused on the thermodynamic optimization of Organic Rankine Cycles (ORCs), coupled with absorption or adsorption cooling units, for combined cooling heating and power (CCHP) generation from biomass combustion. Results were obtained by modelling with the main aim of providing optimization guidelines for the operating conditions of these types of systems, specifically the subcritical or transcritical ORC, when integrated in a CCHP system to supply typical heating and cooling deman...

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

    Science.gov (United States)

    2016-08-01

    Small-Scale W912H0-12-C-0059 Organic Rankine Cycle (ORC) Engine /Generator Technology 5b. GRANT NUMBER 5c. PROGRAM ELEMENT NUMBER 6. AUTHOR( SI 5d...same fuel input. This value is used for calculation of Greenhouse Gas (GHG) reductions and economic results. Life cycle economics of the system are...associated with engine and other electric generator systems , waste heat from steam or heat distribution, waste heat from boiler exhausts, and heat

  5. Constructing and deriving reciprocal trigonometric relations: a functional analytic approach.

    Science.gov (United States)

    Ninness, Chris; Dixon, Mark; Barnes-Holmes, Dermot; Rehfeldt, Ruth Anne; Rumph, Robin; McCuller, Glen; Holland, James; Smith, Ronald; Ninness, Sharon K; McGinty, Jennifer

    2009-01-01

    Participants were pretrained and tested on mutually entailed trigonometric relations and combinatorially entailed relations as they pertained to positive and negative forms of sine, cosine, secant, and cosecant. Experiment 1 focused on training and testing transformations of these mathematical functions in terms of amplitude and frequency followed by tests of novel relations. Experiment 2 addressed training in accordance with frames of coordination (same as) and frames of opposition (reciprocal of) followed by more tests of novel relations. All assessments of derived and novel formula-to-graph relations, including reciprocal functions with diversified amplitude and frequency transformations, indicated that all 4 participants demonstrated substantial improvement in their ability to identify increasingly complex trigonometric formula-to-graph relations pertaining to same as and reciprocal of to establish mathematically complex repertoires.

  6. The emergence of contingent reciprocity in young children.

    Science.gov (United States)

    Warneken, Felix; Tomasello, Michael

    2013-10-01

    Contingent reciprocity is important in theories of the evolution of human cooperation, but it has been very little studied in ontogeny. We gave 2- and 3-year-old children the opportunity to either help or share with a partner after that partner either had or had not previously helped or shared with the children. Previous helping did not influence children's helping. In contrast, previous sharing by the partner led to greater sharing in 3-year-olds but not in 2-year-olds. These results do not support theories claiming either that reciprocity is fundamental to the origins of children's prosocial behavior or that it is irrelevant. Instead, they support an account in which children's prosocial behavior emerges spontaneously but is later mediated by reciprocity. Copyright © 2013 Elsevier Inc. All rights reserved.

  7. The evolution of generalized reciprocity in social interaction networks.

    Science.gov (United States)

    Voelkl, Bernhard

    2015-09-01

    Generalized reciprocity has been proposed as a mechanism for enabling continued cooperation between unrelated individuals. It can be described by the simple rule "help somebody if you received help from someone", and as it does not require individual recognition, complex cognition or extended memory capacities, it has the potential to explain cooperation in a large number of organisms. In a panmictic population this mechanism is vulnerable to defection by individuals who readily accept help but do not help themselves. Here, I investigate to what extent the limitation of social interactions to a social neighborhood can lead to conditions that favor generalized reciprocity in the absence of population structuring. It can be shown that cooperation is likely to evolve if one assumes certain sparse interaction graphs, if strategies are discrete, and if spontaneous helping and reciprocating are independently inherited. Copyright © 2015 Elsevier Inc. All rights reserved.

  8. Lightweight Interactions for Reciprocal Cooperation in a Social Network Game

    CERN Document Server

    Takano, Masanori; Fukuda, Ichiro

    2016-01-01

    The construction of reciprocal relationships requires cooperative interactions during the initial meetings. However, cooperative behavior with strangers is risky because the strangers may be exploiters. In this study, we show that people increase the likelihood of cooperativeness of strangers by using lightweight non-risky interactions in risky situations based on the analysis of a social network game (SNG). They can construct reciprocal relationships in this manner. The interactions involve low-cost signaling because they are not generated at any cost to the senders and recipients. Theoretical studies show that low-cost signals are not guaranteed to be reliable because the low-cost signals from senders can lie at any time. However, people used low-cost signals to construct reciprocal relationships in an SNG, which suggests the existence of mechanisms for generating reliable, low-cost signals in human evolution.

  9. Explaining potential antecedents of workplace social support: reciprocity or attractiveness?

    Science.gov (United States)

    Bowling, Nathan A; Beehr, Terry A; Johnson, Adam L; Semmer, Norbert K; Hendricks, Elizabeth A; Webster, Heather A

    2004-10-01

    Effects of social support are an important topic in occupational stress theories and research, yet little is known about support's potential antecedents. Based on reciprocity theory, the authors hypothesized that the social support received is related to the extent the employee performs organizational citizenship behaviors directed at individuals and to one's social competence; based on the notion of personal attraction, the authors hypothesized that employees' physical attractiveness and sense of humor would be associated with the amount of social support received. In a survey of 123 high school employees and separate ratings of their attractiveness, reciprocity variables were related but attraction variables were not related to social support availability. Further research should examine reciprocity in predicting social support.

  10. The quadratic reciprocity law a collection of classical proofs

    CERN Document Server

    Baumgart, Oswald

    2015-01-01

    This book is the English translation of Baumgart’s thesis on the early proofs of the quadratic reciprocity law (“Über das quadratische Reciprocitätsgesetz. Eine vergleichende Darstellung der Beweise”), first published in 1885. It is divided into two parts. The first part presents a very brief history of the development of number theory up to Legendre, as well as detailed descriptions of several early proofs of the quadratic reciprocity law. The second part highlights Baumgart’s comparisons of the principles behind these proofs. A current list of all known proofs of the quadratic reciprocity law, with complete references, is provided in the appendix. This book will appeal to all readers interested in elementary number theory and the history of number theory.

  11. Design and Fabrication of a Free-Form Reciprocal Roof

    DEFF Research Database (Denmark)

    Parigi, Dario

    2015-01-01

    The paper presents the framework and the design and construction process of a freeform reciprocal pavilion realized during a one-week long workshop with the students of the 1st semester of the Master of Science in Architecture and Design, fall 2014, at Aalborg University. The workshop didactic...... framework is the Performance Aided/Assisted Design (PAD) approach, which focuses on the increasing range of available performance analysis, optimization strategies, interfaces, tools, methodologies, and their ability to foster creativity by increasing designers' understanding of the complex network...... logic of reciprocal structures. It enables to engage in real time in iterative processes that allows unfolding the geometric complexity and turn it into a source of inspiration for expanding the design space and triggering the development of unique, adapted and integrated design solutions. Reciprocal...

  12. Children’s Beliefs in Reciprocation of Biases and Flexibility

    Science.gov (United States)

    Rennels, Jennifer L.

    2015-01-01

    Children display positive and negative biases based on peers’ attractiveness, gender, and race, but it is unclear whether children who associate positive attributes with certain peers also believe those peers think positively of them. In each domain (attractiveness, gender, race), we measured 3- to 11-year-olds’ (N=102) biases and flexibility and their beliefs in reciprocity of bias and flexibility by asking who would think positively of them. Children could choose one of two unfamiliar peers (forced choice assessment) or had the additional options of choosing both or neither peer (non-forced choice assessment). We found children often displayed beliefs in reciprocation, with beliefs in positive bias reciprocation from attractive girls showing the largest effect sizes. These beliefs significantly correlated with and were predictive of children’s positive and negative biases and flexibility. The duality of children’s beliefs may contribute to strengthening their biases and segregating social groups. PMID:25918015

  13. Evaluation of non-reciprocal heterologous immunity between unrelated viruses.

    Science.gov (United States)

    Che, Jenny W; Selin, Liisa K; Welsh, Raymond M

    2015-08-01

    Heterologous immunity refers to the phenomenon whereby a history of an immune response against one pathogen can provide a level of immunity to a second unrelated pathogen. Previous investigations have shown that heterologous immunity is not necessarily reciprocal, such as in the case of vaccinia virus (VACV). Replication of VACV is reduced in mice immune to a variety of pathogens, while VACV fails to induce immunity to several of the same pathogens, including lymphocytic choriomeningitis virus (LCMV). Here we examine the lack of reciprocity of heterologous immunity between VACV and LCMV and find that they induce qualitatively different memory CD8 T cells. However, depending on the repertoire of an individual host, VACV can provide protection against LCMV simply by experimentally amplifying the quantity of T cells cross-reactive with the two viruses. Thus, one cause for lack of reciprocity is differences in the frequencies of cross-reactive T cells in immune hosts. Copyright © 2015 Elsevier Inc. All rights reserved.

  14. Reciprocal relations for effective conductivities of anisotropic media

    Science.gov (United States)

    Nevard, John; Keller, Joseph B.

    1985-11-01

    Any pair of two-dimensional anisotropic media with local conductivity tensors that are functions of position and that are related to one another in a certain reciprocal way are considered. It is proved that their effective conductivity tensors are related to each other in the same way for both spatially periodic media and statistically stationary random media. An inequality involving the effective conductivity tensors of two three-dimensional media that are reciprocally related is also proved. These results extend the corresponding results for locally isotropic media obtained by Keller, Mendelsohn, Hansen, Schulgasser, and Kohler and Papanicolau. They also yield a relation satisfied by the effective conductivity tensor of a medium reciprocal to a translated or rotated copy of itself.

  15. Performance Analysis and Working Fluid Selection of a Supercritical Organic Rankine Cycle for Low Grade Waste Heat Recovery

    Directory of Open Access Journals (Sweden)

    Yourong Li

    2012-08-01

    Full Text Available The performance analysis of a supercritical organic Rankine cycle system driven by exhaust heat using 18 organic working fluids is presented. Several parameters, such as the net power output, exergy efficiency, expander size parameter (SP, and heat exchanger requirement of evaporator and the condenser, were used to evaluate the performance of this recovery cycle and screen the working fluids. The results reveal that in most cases, raising the expander inlet temperature is helpful to improve the net power output and the exergy efficiency. However, the effect of the expander inlet pressure on those parameters is related to the expander inlet temperature and working fluid used. Either lower expander inlet temperature and pressure, or higher expander inlet temperature and pressure, generally makes the net power output more. Lower expander inlet temperature results in larger total heat transfer requirement and expander size. According to the screening criteria of both the higher output and the lower investment, the following working fluids for the supercritical ORC system are recommended: R152a and R143a.

  16. Organic Rankine-cycle power systems working fluids study: Topical report No. 1: Fluorinol 85. [85 mole % trofluoroethanol in water

    Energy Technology Data Exchange (ETDEWEB)

    Jain, M.L.; Demirgian, J.C.; Cole, R.L.

    1986-09-01

    An investigation to experimentally determine the thermal stability limits and degradation rates of Fluorinol 85 as a function of maximum cycle temperatures was initiated in 1982. Following the design and construction of a dynamic test loop capable of simulating the thermodynamic conditions of possible prototypical organic Rankine-cycle (ORC) power systems, several test runs were completed. The Fluorinol 85 test loop was operated for about 3800 h, covering a temperature range of 525-600/sup 0/F. Both liquid and noncondensable vapor (gas) samples were drawn periodically and analyzed using capillary column gas chromatography, gas chromatography/mass spectrometry and mass spectrometry. Results indicate that Fluorinol 85 would not decompose significantly over an extended period of time, up to a maximum cycle temperature of 550/sup 0/F. However, 506-h data at 575/sup 0/F show initiation of significant degradation. The 770-h data at 600/sup 0/F, using a fresh charge of Fluorinol 85, indicate an annual degradation rate of more than 17.2%. The most significant degradation product observed is hydrofluoric acid, which could cause severe corrosion in an ORC system. Devices to remove the hydrofluoric acid and prevent extreme temperature excursions are necessary for any ORC system using Fluorinol 85 as a working fluid.

  17. Exergy analysis of an integrated solid oxide fuel cell and organic Rankine cycle for cooling, heating and power production

    Energy Technology Data Exchange (ETDEWEB)

    Al-Sulaiman, Fahad A. [Mechanical and Aerospace Engineering Department, Carleton University 1125 Colonel By Drive, Ottawa, Ontario (Canada); Dincer, Ibrahim [Faculty of Engineering and Applied Science, University of Ontario Institute of Technology 2000 Simcoe Street North, Oshawa, Ontario (Canada); Hamdullahpur, Feridun [Mechanical and Mechatronics Engineering Department, University of Waterloo, 200 University Avenue West, Waterloo, Ontario (Canada)

    2010-04-15

    The study examines a novel system that combined a solid oxide fuel cell (SOFC) and an organic Rankine cycle (ORC) for cooling, heating and power production (trigeneration) through exergy analysis. The system consists of an SOFC, an ORC, a heat exchanger and a single-effect absorption chiller. The system is modeled to produce a net electricity of around 500 kW. The study reveals that there is 3-25% gain on exergy efficiency when trigeneration is used compared with the power cycle only. Also, the study shows that as the current density of the SOFC increases, the exergy efficiencies of power cycle, cooling cogeneration, heating cogeneration and trigeneration decreases. In addition, it was shown that the effect of changing the turbine inlet pressure and ORC pump inlet temperature are insignificant on the exergy efficiencies of the power cycle, cooling cogeneration, heating cogeneration and trigeneration. Also, the study reveals that the significant sources of exergy destruction are the ORC evaporator, air heat exchanger at the SOFC inlet and heating process heat exchanger. (author)

  18. An Innovative Application of a Solar Storage Wall Combined with the Low-Temperature Organic Rankine Cycle

    Directory of Open Access Journals (Sweden)

    Tzu-Chen Hung

    2014-01-01

    Full Text Available The objective of this study is to collect energy on the waste heat from air produced by solar ventilation systems. This heat used for electricity generation by an organic Rankine cycle (ORC system was implemented. The advantages of this method include the use of existing building’s wall, and it also provides the region of energy scarcity for reference. This is also an innovative method, and the results will contribute to the efforts made toward improving the design of solar ventilation in the field of solar thermal engineering. In addition, ORC system would help generate electricity and build a low-carbon building. This study considered several critical parameters such as length of the airflow channel, intensity of solar radiation, pattern of the absorber plate, stagnant air layer, and operating conditions. The simulation results show that the highest outlet temperature and heat collecting efficiency of solar ventilation system are about 120°C and 60%, respectively. The measured ORC efficiency of the system was 6.2%. The proposed method is feasible for the waste heat from air produced by ventilation systems.

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

    Science.gov (United States)

    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

  20. Technical Analysis of Organic Rankine Cycle System Using Low-Temperature Source to Generate Electricity in Ship

    Directory of Open Access Journals (Sweden)

    Akram Faisal

    2017-01-01

    Full Text Available Nowadays, the shipping sector has growth rapidly as followed by the increasing of world population and the demands for public transportation via sea. This issue entails the large attention on emission, energy efficiency and fuel consumption on the ship. Waste Heat Recovery (WHR is one of the solution to overcome the mentioned issue and one of the WHR method is by installing Organic Rankine Cycle (ORC system in ship. ORC demonstrate to recover and exploit the low temperature waste heat rejected by the ship power generation plant. The main source of heat to be utilized is obtained from container ship (7900 kW BHP, DWT 10969 mt ship jacket water cooling system and use R-134a as a refrigerant. The main equipment consists of evaporator, condenser, pump and steam turbine to generate the electricity. The main objective is to quantifying the estimation of electrical power which can be generated at typical loads of the main engine. As the final result of analysis, the ORC system is able to generate the electricity power ranged from 77,5% - 100% of main engine load producing power averagely 57,69 kW.

  1. Study on Mixed Working Fluids with Different Compositions in Organic Rankine Cycle (ORC Systems for Vehicle Diesel Engines

    Directory of Open Access Journals (Sweden)

    Kai Yang

    2014-08-01

    Full Text Available One way to increase the thermal efficiency of vehicle diesel engines is to recover waste heat by using an organic Rankine cycle (ORC system. Tests were conducted to study the running performances of diesel engines in the whole operating range. The law of variation of the exhaust energy rate under various engine operating conditions was also analyzed. A diesel engine-ORC combined system was designed, and relevant evaluation indexes proposed. The variation of the running performances of the combined system under various engine operating conditions was investigated. R245fa and R152a were selected as the components of the mixed working fluid. Thereafter, six kinds of mixed working fluids with different compositions were presented. The effects of mixed working fluids with different compositions on the running performances of the combined system were revealed. Results show that the running performances of the combined system can be improved effectively when mass fraction R152a in the mixed working fluid is high and the engine operates with high power. For the mixed working fluid M1 (R245fa/R152a, 0.1/0.9, by mass fraction, the net power output of the combined system reaches the maximum of 34.61 kW. Output energy density of working fluid (OEDWF, waste heat recovery efficiency (WHRE, and engine thermal efficiency increasing ratio (ETEIR all reach their maximum values at 42.7 kJ/kg, 10.90%, and 11.29%, respectively.

  2. About the prediction of Organic Rankine Cycles performances integrating local high-fidelity turbines simulation and uncertainties

    Science.gov (United States)

    Congedo, Pietro; de Santis, Dante; Geraci, Gianluca

    2014-11-01

    Organic Rankine Cycles (ORCs) are of key-importance when exploiting energy systems with a high efficiency. The variability of renewable heat sources makes more complex the global performance prediction of a cycle. The thermodynamic properties of the complex fluids used in the process are another source of uncertainty. The need for a predictive and robust simulation tool of ORCs remains strong. A high-order accurate Residual Distribution scheme has been recently developed for efficiently computing a turbine stage on unstructured grids, including advanced equations of state in order to take into account the complex fluids used in ORCs. Advantages in using high-order methods have been highlighted, in terms of number of degrees of freedom and computational time used, for computing the numerical solution with a greater accuracy compared to lower-order methods, even for shocked flows. The objective of this work is to quantify the numerical error with respect to the various sources of uncertainty of the ORC turbine, thus providing a very high-fidelity prediction in the coupled physical/stochastic space.

  3. Modelling the Influence of Climate on the Performance of the Organic Rankine Cycle for Industrial Waste Heat Recovery

    Directory of Open Access Journals (Sweden)

    Ivan Korolija

    2016-05-01

    Full Text Available This paper describes a study of the relative influences of different system design decisions upon the performance of an organic Rankine cycle (ORC used to generate electricity from foundry waste heat. The design choices included concern the working fluid, whether to use a regenerator and the type of condenser. The novelty of the research lies in its inclusion of the influence of both the ORC location and the auxiliary electricity used by the pumps and fans in the ORC power system. Working fluids suitable for high temperature applications are compared, including three cyclic siloxanes, four linear siloxanes and three aromatic fluids. The ORC is modelled from first principles and simulation runs carried out using weather data for 106 European locations and a heat input profile that was derived from empirical data. The impact of design decisions upon ORC nominal efficiency is reported followed by the impact upon annual system efficiency in which variations in heat input and the condition of outdoor air over a year are considered. The main conclusion is that the location can have a significant impact upon the efficiency of ORC systems due to the influence of climate upon the condenser and auxiliary electricity requirements.

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

    Science.gov (United States)

    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.

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

    Science.gov (United States)

    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.

  6. Thermo-Economic Analysis of Zeotropic Mixtures and Pure Working Fluids in Organic Rankine Cycles for Waste Heat Recovery

    Directory of Open Access Journals (Sweden)

    Florian Heberle

    2016-03-01

    Full Text Available We present a thermo-economic analysis of an Organic Rankine Cycle (ORC for waste heat recovery. A case study for a heat source temperature of 150 °C and a subcritical, saturated cycle is performed. As working fluids R245fa, isobutane, isopentane, and the mixture of isobutane and isopentane are considered. The minimal temperature difference in the evaporator and the condenser, as well as the mixture composition are chosen as variables in order to identify the most suitable working fluid in combination with optimal process parameters under thermo-economic criteria. In general, the results show that cost-effective systems have a high minimal temperature difference ΔTPP,C at the pinch-point of the condenser and a low minimal temperature difference ΔTPP,E at the pinch-point of the evaporator. Choosing isobutane as the working fluid leads to the lowest costs per unit exergy with 52.0 €/GJ (ΔTPP,E = 1.2 K; ΔTPP,C = 14 K. Considering the major components of the ORC, specific costs range between 1150 €/kW and 2250 €/kW. For the zeotropic mixture, a mole fraction of 90% isobutane leads to the lowest specific costs per unit exergy. A further analysis of the ORC system using isobutane shows high sensitivity of the costs per unit exergy for the selected cost estimation methods and for the isentropic efficiency of the turbine.

  7. Performance of Siloxane Mixtures in a High-Temperature Organic Rankine Cycle Considering the Heat Transfer Characteristics during Evaporation

    Directory of Open Access Journals (Sweden)

    Theresa Weith

    2014-08-01

    Full Text Available The application of the Organic Rankine Cycle to high temperature heat sources is investigated on the case study of waste heat recovery from a selected biogas plant. Two different modes of operation are distinguished: pure electric power and combined heat and power generation. The siloxanes hexamethyldisiloxane (MM and octamethyltrisiloxane (MDM are chosen as working fluids. Moreover, the effect of using mixtures of these components is analysed. Regarding pure electricity generation, process simulations using the simulation tool Aspen Plus show an increase in second law efficiency of 1.3% in case of 97/03 wt % MM/MDM-mixture, whereas for the combined heat and power mode a 60/40 wt % MM/MDM-mixture yields the highest efficiency with an increase of nearly 3% compared to most efficient pure fluid. Next to thermodynamic analysis, measurements of heat transfer coefficients of these siloxanes as well as their mixtures are conducted and Kandlikar’s correlation is chosen to describe the results. Based on that, heat exchanger areas for preheater and evaporator are calculated in order to check whether the poorer heat transfer characteristics of mixtures devalue their efficiency benefit due to increased heat transfer areas. Results show higher heat transfer areas of 0.9% and 14%, respectively, compared to MM.

  8. Test Requirements and Conceptual Design for a Potassium Test Loop to Support an Advanced Potassium Rankine Cycle Power Conversion Systems

    Energy Technology Data Exchange (ETDEWEB)

    Yoder, JR.G.L.

    2006-03-08

    Parameters for continuing the design and specification of an experimental potassium test loop are identified in this report. Design and construction of a potassium test loop is part of the Phase II effort of the project ''Technology Development Program for an Advanced Potassium Rankine Power Conversion System''. This program is supported by the National Aeronautics and Space Administration. Design features for the potassium test loop and its instrumentation system, specific test articles, and engineered barriers for ensuring worker safety and protection of the environment are described along with safety and environmental protection requirements to be used during the design process. Information presented in the first portion of this report formed the basis to initiate the design phase of the program; however, the report is a living document that can be changed as necessary during the design process, reflecting modifications as additional design details are developed. Some portions of the report have parameters identified as ''to be determined'' (TBD), reflecting the early stage of the overall process. In cases where specific design values are presently unknown, the report attempts to document the quantities that remain to be defined in order to complete the design of the potassium test loop and supporting equipment.

  9. Economic assessment of greenhouse gas reduction through low-grade waste heat recovery using organic Rankine cycle (ORC)

    Energy Technology Data Exchange (ETDEWEB)

    Imran, Muhammad; Park, Byung Sik; Kim, Hyouck Ju; Usman, Muhammad [University of Science and Technology, Daejeon (Korea, Republic of); Lee, Dong Hyun [Korea Institute of Energy Research, Daejeon (Korea, Republic of)

    2015-02-15

    Low-grade waste heat recovery technologies reduce the environmental impact of fossil fuels and improve overall efficiency. This paper presents the economic assessment of greenhouse gas (GHG) reduction through waste heat recovery using organic Rankine cycle (ORC). The ORC engine is one of the mature low temperature heat engines. The low boiling temperature of organic working fluid enables ORC to recover low-temperature waste heat. The recovered waste heat is utilized to produce electricity and hot water. The GHG emissions for equivalent power and hot water from three fossil fuels-coal, natural gas, and diesel oil-are estimated using the fuel analysis approach and corresponding emission factors. The relative decrease in GHG emission is calculated using fossil fuels as the base case. The total cost of the ORC system is used to analyze the GHG reduction cost for each of the considered fossil fuels. A sensitivity analysis is also conducted to investigate the effect of the key parameter of the ORC system on the cost of GHG reduction. Throughout the 20-year life cycle of the ORC plant, the GHG reduction cost for R245fa is 0.02 $/kg to 0.04 $/kg and that for pentane is 0.04 $/kg to 0.05 $/kg. The working fluid, evaporation pressure, and pinch point temperature difference considerably affect the GHG emission.

  10. Economic, Energetic, and Environmental Performance of a Solar Powered Organic Rankine Cycle with Electric Energy Storage in Different Commercial Buildings

    Directory of Open Access Journals (Sweden)

    Emily Spayde

    2018-01-01

    Full Text Available This paper presents an analysis to determine the economic, energetic, and environmental benefits that could be obtained from the implementation of a combined solar-power organic Rankine cycle (ORC with electric energy storage (EES to supply electricity to several commercial buildings including a large office, a small office, and a full service restaurant. The operational strategy for the ORC-EES system consists in the ORC charging the EES when the irradiation level is sufficient to generate power, and the EES providing electricity to the building when there is not irradiation (i.e., during night time. Electricity is purchased from the utility grid unless it is provided by the EES. The potential of the proposed system to reduce primary energy consumption (PEC, carbon dioxide emission (CDE, and cost was evaluated. Furthermore, the available capital cost for a variable payback period for the ORC-EES system was determined for each of the evaluated buildings. The effect of the number of solar collectors on the performance of the ORC-EES is also studied. Results indicate that the proposed ORC-EES system is able to satisfy 11%, 13%, and 18% of the electrical demand for the large office, the small office and the restaurant, respectively.

  11. Fairness and Reciprocity in the Hawk-Dove Game

    DEFF Research Database (Denmark)

    Poulsen, Anders; Neugebauer, Tibor; Schram, Arthur

    2002-01-01

    We study fairness and reciprocity in a Hawk-Dove game, using an experimental approach. This allows us to test various models in one framework. We observe a large extent of selfish and rational behavior. Our results are inconsistent with leading models in this field.......We study fairness and reciprocity in a Hawk-Dove game, using an experimental approach. This allows us to test various models in one framework. We observe a large extent of selfish and rational behavior. Our results are inconsistent with leading models in this field....

  12. Bending-active reciprocal structures based on equilateral polyhedral geometries

    DEFF Research Database (Denmark)

    Popovic Larsen, Olga; BRANCART, Stijn; DE TEMMERMAN, Niels

    2017-01-01

    of parts of reciprocal bending-active components based on a selection of polyhedral dome types. To simplify the assembly of the structures and avoid the manual bending of the components on site, we introduce the concept of a double-layered, pre-bent component. Finally, this paper presents the development......, fabrication and assembly of the ReciPlyDome, a full-scale prototype of a bending-active reciprocal dome with double-layered components. Preliminary analyses of the load-bearing behaviour show the potential of these systems for material-efficient, lightweight structures. The research presented in this paper...

  13. Nebula: reconstruction and visualization of scattering data in reciprocal space.

    Science.gov (United States)

    Reiten, Andreas; Chernyshov, Dmitry; Mathiesen, Ragnvald H

    2015-04-01

    Two-dimensional solid-state X-ray detectors can now operate at considerable data throughput rates that allow full three-dimensional sampling of scattering data from extended volumes of reciprocal space within second to minute time-scales. For such experiments, simultaneous analysis and visualization allows for remeasurements and a more dynamic measurement strategy. A new software, Nebula, is presented. It efficiently reconstructs X-ray scattering data, generates three-dimensional reciprocal space data sets that can be visualized interactively, and aims to enable real-time processing in high-throughput measurements by employing parallel computing on commodity hardware.

  14. Reciprocity calibration of impulse responses of acoustic emission transducers.

    Science.gov (United States)

    Hatano, H; Chaya, T; Watanabe, S; Jinbo, K

    1998-01-01

    By means of reciprocity calibration in Rayleigh-wave and longitudinal-wave sound fields, frequency characteristics of amplitude and phase of absolute sensitivity of acoustic emission transducers were measured on the basis of the newly derived complex reciprocity parameters, and the impulse responses were obtained through inverse Fourier transform. Calibration results were confirmed with supplemental experiments in which the fracturing of a pencil lead was utilized for the source of elastic waves. Impulse responses of acoustic emission transducers to both the Rayleigh-wave and longitudinal-wave displacement velocities were determined by means of purely electrical measurements without the use of mechanical sound sources or reference transducers.

  15. Viability study for application of combined reheater cycle (CRC) to fluidized bed combustion plants; Estudio de Viabilidad para la Aplicacion del Ciclo de Recalentamiento Combinado (CRC) a Plantas de Combustion de Lecho Fuido Atmosferico

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1998-12-01

    Basically, the project try to analyze the application viability of a first reheating in steam cycles of little power plants, useful mainly for biomass and wastes, in our case with coal blends; and a second reheating of the steam in conventional and fluidized bed combustion plants. Using in both cases the thermic energy of the exhaust gases from one gas turbine. The advantages of the CRC cycle are: (1) Reduction of the moisture in the turbine, increasing the energy efficiency and blade protection. (2) To take advantage of the waste gas energy from the gas turbine in optimum way. (3) Great operation flexibility under good efficiency results. In general, the system can use the synergy between gas, coal and waste energies with the highest global efficiency. (Author)

  16. evaluation of layer type chickens under reciprocal recurrent

    African Journals Online (AJOL)

    DR. AMINU

    ABSTRACT. Matings within pure male and female lines, and between pure male and female lines were carried out to produce purebred male line (AA x AA), female line (BB x BB), cross (AA x BB) and reciprocal cross (BB x AA). A total number of 364 pullets arising from 207 hens and 23 cocks in generation 1 and 440 pullets ...

  17. Reciprocal Relationships between Math Self-Concept and Math Anxiety

    NARCIS (Netherlands)

    Ahmed, Wondimu; Minnaert, Alexander; Kuyper, Hans; Van der Werf, Greetje

    The present study examined the reciprocal relationships between self-concept and anxiety in mathematics. A sample of 495 grade 7 students (51% girls) completed self-report measures assessing self-concept and anxiety three times in a school year. Structural equation modeling was used to test a

  18. Explaining Cooperation in Groups: Testing Models of Reciprocity and Learning

    Science.gov (United States)

    Biele, Guido; Rieskamp, Jorg; Czienskowski, Uwe

    2008-01-01

    What are the cognitive processes underlying cooperation in groups? This question is addressed by examining how well a reciprocity model, two learning models, and social value orientation can predict cooperation in two iterated n-person social dilemmas with continuous contributions. In the first of these dilemmas, the public goods game,…

  19. Achievement Emotions and Academic Performance: Longitudinal Models of Reciprocal Effects

    Science.gov (United States)

    Pekrun, Reinhard; Lichtenfeld, Stephanie; Marsh, Herbert W.; Murayama, Kou; Goetz, Thomas

    2017-01-01

    A reciprocal effects model linking emotion and achievement over time is proposed. The model was tested using five annual waves of the Project for the Analysis of Learning and Achievement in Mathematics (PALMA) longitudinal study, which investigated adolescents' development in mathematics (Grades 5-9; N = 3,425 German students; mean starting…

  20. Potential Reciprocal Relationship between Motivation and Achievement: A Longitudinal Study

    Science.gov (United States)

    Liu, Yuan; Hou, Shumeng

    2018-01-01

    Among the non-cognitive factors that influence academic achievement, intrinsic motivation has been found to be a potential reciprocal factor. The present study aims to determine the causal relationship between other types of motivation and academic achievement. For this purpose, a large-scale data survey, the National Education Longitudinal Study…

  1. Paradoxical Effects of Feedback in International Online Reciprocal Peer Tutoring

    Science.gov (United States)

    Topping, K. J.; Dehkinet, R.; Blanch, S.; Corcelles, M.; Duran, D.

    2013-01-01

    This paper reports an online reciprocal peer tutoring project for improving language competence in Spanish and English. Students aged 9-12 years from Scotland and Catalonia were matched to act as tutors in their own language and as tutees in a modern foreign language. Students were intended to improve both their first language (through helping the…

  2. Reciprocity and its utilization in ultrasonic flow meters

    Energy Technology Data Exchange (ETDEWEB)

    Lunde, Per; Vestrheim, Magne; Boe, Reidar; Smoergrav, Skule; Abrahamsen, Atle K.

    2005-07-01

    In ultrasonic transit time flow meters for gas and liquid (USMs), the flow direction, the flow velocity and the sound velocity are estimated from the measured up- and downstream transit times. At no-flow conditions, the up- and downstream transit times of such meters should ideally be the same, or the difference should be negligible. This may not be the case unless special precautions are made. In order to reduce the possibility of the meter to detect a false flow at no-flow conditions, USMs are typically ''dry calibrated'' before being installed in the field. ''Dry calibration'' (which may be made in different ways), in general involves measurement of (a) the time delays due to electronics, cables and transducers, (b) the so called ''{delta}t-correction'' (for each acoustic path, also denoted ''zero flow offset factor''), and (c) geometrical parameters. Various {delta}t-correction approaches may be used by different manufacturers, but these are basically similar and have the same purpose: to reduce the false flow detection and improve the accuracy at low and no-flow conditions (''zero flow adjustment''), without significantly affecting the accuracy at the high velocity measurements. The AGA-9 report and the API MPMS Ch. 5.8 standard both prescribe need for ''zero flow verification test (zero test)'' or ''zeroing the meter'', for gas and liquid USMs, respectively. Advances in USM technology based on the electro acoustic reciprocity principle have provided methods for reduction or even neglect ion of the need for ''{delta} t-correction'' of USMs. That means, if the USM measurement system is reciprocal, and operated in a ''sufficiently reciprocal'' way, the ''{delta}t-correction'' may be negligibly small over the operational range of pressure and temperature, and

  3. Standard guide for determining friction energy dissipation in reciprocating tribosystems

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    2010-01-01

    1.1 This guide covers and is intended for use in interpreting the friction forces recorded in reciprocating tribosystems. The guide applies to any reciprocating tribosystem, whether it is a wear or fretting test or an actual machine or device. 1.2 The energy dissipation guide was developed in analyzing friction results in the Test Method G133 reciprocating ball-on-flat test, but it applies to other ASTM or ISO reciprocating tests. This technique is frequently used to record the friction response in fretting tribosystems. 1.3 Specimen material may play some role in the results if the materials under test display viscoelastic behavior. This guide as written is for metals, plastics, and ceramics that do not display viscoelastic behavior. It also applies to lubricated and non-lubricated contacts. 1.4 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard. 1.5 This standard does not purport to address all of the safety concerns, if any, asso...

  4. Emerging signs of strong reciprocity in human ontogeny

    Directory of Open Access Journals (Sweden)

    Erin eRobbins

    2011-12-01

    Full Text Available Strong reciprocity is considered here as the propensity to sacrifice resources to be kind or to punish in response to prior acts, a behavior not simply reducible to self-interest and a likely force behind human cooperation and sociality. The aim was to capture emerging signs of strong reciprocity in human ontogeny. Three- and five-year-old middle class American children (N=162 were tested in a simple, multiple round, three-way sharing game involving the child, a generous puppet, and a stingy puppet. At the end of the game, the child was offered an opportunity to sacrifice some of her personal gains to punish one of the puppets. By three years, American children demonstrate a willingness to engage in costly punishment. However, only five-year-olds show some evidence of strong reciprocity by orienting their punishment systematically toward the stingy puppet. Further analyses and 3 additional control conditions demonstrate that such propensity is not simply reducible to a straight imitation, or b inequity aversion. To assess the relative universality of such development, a group of five- to six-year-old children from rural Samoa (N=14 were tested and compared to age and gender matched American children. Samoan children did not manifest the same propensity toward strong reciprocity. The results are interpreted as pointing to 1 the developmental emergence of an ethical stance between three and five years of age, and 2 that the expression of such stance by young children could depend on culture.

  5. 32 CFR 634.16 - Reciprocal state-military action.

    Science.gov (United States)

    2010-07-01

    ... follow provisions of the applicable Status of Forces Agreement (SOFA), the law of the host nation concerning reciprocal suspension and revocation, and other international agreements. To the extent an... have prior authorization to negotiate and conclude such an international agreement in accordance with...

  6. Modern Social Science Concepts, Proportionate Reciprocity, Modesty, and Democracy

    Directory of Open Access Journals (Sweden)

    Gerasimos T. SOLDATOS

    2014-06-01

    Full Text Available Proportionate Reciprocity, Modesty, and Democracy, are the key concepts in Aristotle’s economics of exchange. The following correspondence of these concepts with modern social science may be contemplated: (a Ideally, reciprocal justice in bilateral bargaining to minimize expenditure given utility levels results in Pareto-efficient, envy-free, equitable outcomes. (b Practically, bargaining under the threat or actual recontracting may act as a surrogate of reciprocal justice, leading to an N-person contract topology. (c But, recontracting is subject to practical limitations too, in which case near-reciprocal justice/general equilibrium outcomes may be fostered if, as a surrogate of recontracting, modesty in interaction is exhibited in an evolutionarily-stable-strategy fashion. (d That is, incomplete recontracting amounts to asymmetric agent-type information, which in turn lays the ground for injustices; the same lack of information prevents rectificatory justice from being efficient and hence, modesty can be efficient only if it operates as a social norm and hence, only in a modest polity, which can be no other than democracy.

  7. Reciprocal Commitment in Academic Careers? Finnish Implications and International Trends

    Science.gov (United States)

    Siekkinen, Taru; Kuoppala, Kari; Pekkola, Elias; Välimaa, Jussi

    2017-01-01

    This study explores the nature of reciprocal commitment in academic careers. The article is based on a survey conducted in autumn 2013 among fixed-term employees at eight major universities in Finland (N = 810). The analysis is focusing on researchers who have a doctoral degree and who are working on a fixed-term contract at their university (n =…

  8. Evaluation of layer type chickens under reciprocal recurrent selection

    African Journals Online (AJOL)

    Matings within pure male and female lines, and between pure male and female lines were carried out to produce purebred male line (AA x AA), female line (BB x BB), cross (AA x BB) and reciprocal cross (BB x AA). A total number of 364 pullets arising from 207 hens and 23 cocks in generation 1 and 440 pullets from 70 ...

  9. Three cases of mosaicism for balanced reciprocal translocations

    NARCIS (Netherlands)

    Leegte, B; Sikkema-Raddatz, B; Hordijk, R; Bouman, K; van Essen, T; Castedo, S; de Jong, B

    1998-01-01

    Mosaicism for a balanced reciprocal translocation (BRTM) is rare. As far as we know only 26 cases of BRTM, demonstrated in lymphocyte cultures, have been described, five of which had an abnormal phenotype. Prenatally three confirmed cases with a normal phenotypic outcome have been described. Here we

  10. Unilateral or Reciprocal Climate Policy? Experimental Evidence from China

    Directory of Open Access Journals (Sweden)

    Thomas Bernauer

    2016-09-01

    Full Text Available The traditional political economy account of global climate change governance directs our attention to fundamental collective action problems associated with global public goods provision, resulting from positive or negative externalities as well as freeriding. The governance architecture of the 1997 Kyoto Protocol uses the traditional approaches of international diplomacy for addressing such challenges: legally binding commitments based on principles of reciprocity and (fair cost/burden sharing via formalized carbon-budgeting. Yet, the 2015 Paris Agreement has essentially abandoned this approach, as it now operates on the basis of internationally coordinated and monitored unilateralism. On the presumption that public opinion matters for government policy, we examine how citizens view this shift in climate policy from reciprocity to unilateralism, after many years of exposure to strong reciprocity rhetoric by governments and stakeholders. To that end, we fielded a survey experiment in China, the world’s largest greenhouse gas (GHG emitter. The results show that there is, perhaps surprisingly, strong and robust public support for unilateral, non-reciprocal climate policy. To the extent China is interested in pushing ahead with ambitious and thus costly GHG reduction policies, our results suggest that China can leverage segments of public support in order to overcome domestic obstacles to GHG mitigation policies.

  11. Three-dimensional Reciprocal Structures: Morphology, Concepts, Generative Rules

    DEFF Research Database (Denmark)

    Parigi, Dario; Pugnale, Alberto

    2012-01-01

    This paper present seven different three dimensional structures based on the principle of structural reciprocity with superimposition joint and standardized un-notched elements. Such typology could be regarded as being intrinsically three-dimensional because elements sit one of the top of the oth...

  12. 77 FR 20743 - Airworthiness Directives; Lycoming Engines Reciprocating Engines

    Science.gov (United States)

    2012-04-06

    ... Federal Aviation Administration 14 CFR Part 39 RIN 2120-AA64 Airworthiness Directives; Lycoming Engines Reciprocating Engines AGENCY: Federal Aviation Administration (FAA), DOT. ACTION: Supplemental notice of... airworthiness directive (AD) for certain Lycoming Engines (L)O-360, (L)IO-360, AEIO-360, O-540, IO-540, AEIO-540...

  13. 77 FR 5167 - Airworthiness Directives; Lycoming Engines Reciprocating Engines

    Science.gov (United States)

    2012-02-02

    ...-26-AD; Amendment 39-16909; AD 71-13-01R1] RIN 2120-AA64 Airworthiness Directives; Lycoming Engines Reciprocating Engines AGENCY: Federal Aviation Administration (FAA), DOT. ACTION: Final rule; rescission. SUMMARY: We are rescinding an airworthiness directive (AD) for Lycoming Engines model TIO-540-A series...

  14. 77 FR 58003 - Airworthiness Directives; Lycoming Engines Reciprocating Engines

    Science.gov (United States)

    2012-09-19

    ...-20-AD; Amendment 39-17196; AD 2012-19-01] RIN 2120-AA64 Airworthiness Directives; Lycoming Engines Reciprocating Engines AGENCY: Federal Aviation Administration (FAA), DOT. ACTION: Final rule. SUMMARY: We are superseding an existing airworthiness directive (AD) for certain Lycoming Engines (L)O-360, (L)IO-360, AEIO...

  15. Non-traditional vibration mitigation methods for reciprocating compressor system

    NARCIS (Netherlands)

    Eijk, A.; Lange, T.J. de; Vreugd, J. de; Slis, E.J.P.

    2016-01-01

    Reciprocating compressors generate vibrations caused by pulsation-induced forces, mechanical (unbalanced) free forces and moments, crosshead guide forces and cylinder stretch forces. The traditional way of mitigating the vibration and cyclic stress levels to avoid fatigue failure of parts of the

  16. Cardiovascular response to resistive and non-resistive reciprocal ...

    African Journals Online (AJOL)

    Background: Reciprocal pulley exercise is usually recommended for physiotherapy patients undergoing rehabilitation for muscle strengthening exercises or improvement in joint range of motion but, very little is known of its effects on the cardiovascular system. Aims: This study aimed at investigating the blood pressure and ...

  17. Performance of oysters in reciprocal transplants between two ...

    African Journals Online (AJOL)

    Oyster spat were reciprocally transplanted between Benya Lagoon at Elmina and Nakwa Lagoon at Nakwa and grown on cultches. Shell growth, dry meat weight, and survival of the transplants were monitored for at least six months and compared with their counterparts at their new locations as well as their places of origin.

  18. Modeling of nonlinear responses for reciprocal transducers involving polarization switching

    DEFF Research Database (Denmark)

    Willatzen, Morten; Wang, Linxiang

    2007-01-01

    Nonlinearities and hysteresis effects in a reciprocal PZT transducer are examined by use of a dynamical mathematical model on the basis of phase-transition theory. In particular, we consider the perovskite piezoelectric ceramic in which the polarization process in the material can be modeled by L...

  19. Reciprocity as Sustainability in Campus-Community Partnership

    Science.gov (United States)

    Bloomgarden, Alan

    2013-01-01

    The concept of reciprocity permeates the literature on campus-community partnership as a matter of principle, aspiration, and--ideally--best practice. More recently, principles and practices of sustainability have pervaded scholarly and popular discourse, emerging from and applying to environmental studies, economic development, and social justice…

  20. Reciprocal Relationships between Job Resources, Personal Resources, and Work Engagement

    Science.gov (United States)

    Xanthopoulou, Despoina; Bakker, Arnold B.; Demerouti, Evangelia; Schaufeli, Wilmar B.

    2009-01-01

    This study examined longitudinal relationships between job resources, personal resources, and work engagement. On the basis of Conservation of Resources theory, we hypothesized that job resources, personal resources, and work engagement are reciprocal over time. The study was conducted among 163 employees, who were followed-up over a period of 18…

  1. Longitudinal Study on Reciprocity between Personality Traits and Parenting Stress

    Science.gov (United States)

    Rantanen, Johanna; Tillemann, Kati; Metsäpelto, Riitta-Leena; Kokko, Katja; Pulkkinen, Lea

    2015-01-01

    Reciprocal associations between the Big Five personality traits and parenting stress--including both parents' feelings of their distress and perception of their incompetence as parents--were studied with 248 participants (49% of which were males). Longitudinal data, collected at ages 33/36, 42 and 50 years, were used. Cross-lagged path analysis…

  2. Reciprocal Relations between Children's Sleep and Their Adjustment over Time

    Science.gov (United States)

    Kelly, Ryan J.; El-Sheikh, Mona

    2014-01-01

    Child sleep and adjustment research with community samples is on the rise with a recognized need of explicating this association. We examined reciprocal relations between children's sleep and their internalizing and externalizing symptoms using 3 waves of data spanning 5 years. Participants included 176 children at Time 1 (M = 8.68 years; 69%…

  3. Apical extrusion of debris using reciprocating files and rotary ...

    African Journals Online (AJOL)

    Background: To compare the preparation time and amount of apically extruded debris after the preparation of root canals in extracted human teeth using the reciprocating files and rotary nickel.titanium systems. Procedure: Sixty extracted human mandibular premolars were used. The root canals were instrumented using ...

  4. Social Dilemmas and Indirect Reciprocity: A systematic review

    Directory of Open Access Journals (Sweden)

    Cristian Acosta

    2014-08-01

    Full Text Available Indirect reciprocity is an evolutionary theory of altruism and cooperation in social dilemmas. Its explanation of cooperation incorporates information on the reputation people hold of other people regarding whether they are cooperative or not. This study systematically reviewed the current empirical literature on indirect reciprocity in social dilemma situations. The following databases were consulted: ScienceDirect, EBSCO, and OVID, using has key words "indirect reciprocity" AND "dilemma" OR "cooperation" OR "charity". Twenty-three articles were selected which met the inclusion criteria (papers written in English and studies whose methodology was based on experimental games and the theories, objectives, the main types of samples used, and main results were analyzed. The results show that the games used were the indirect reciprocity and public goods games, which may vary according to the objectives. It was found that reputation is a key variable that helps to promote cooperation. In turn, information on previous cooperation helps to build reputation, which is subsequently involved in the decision to cooperate with others. Finally, we highlight the need for more experimental studies that incorporate other explanatory variables and evaluate them in new contexts.

  5. Grooming reciprocity in female tibetan macaques macaca thibetana.

    Science.gov (United States)

    Xia, Dongpo; Li, Jinhua; Garber, Paul A; Sun, Lixing; Zhu, Yong; Sun, Binghua

    2012-06-01

    Grooming among nonhuman primates is widespread and may represent an important service commodity that is exchanged within a biological marketplace. In this study, using focal animal sampling methods, we recorded grooming relationships among 12 adult females in a free-ranging group of Tibetan macaques (Macaca thibetana) at Huangshan, China, to determine the influence of rank and kinship on grooming relationships, and whether females act as reciprocal traders (exchange grooming received for grooming given) or interchange traders (interchange grooming for social tolerance or other commodities). The results showed that: (1) grooming given was positively correlated with grooming received; (2) kinship did not exert a significant influence on grooming reciprocity; and (3) grooming reciprocity occurred principally between individuals of adjacent rank; however, when females of different rank groomed, females tended to groom up the hierarchy (lower ranking individuals groomed higher ranking individuals more than vice versa). Our results support the contention that both grooming reciprocity and the interchange of grooming for tolerance represent important social tactics used by female Tibetan macaques. © 2012 Wiley Periodicals, Inc.

  6. Modeling time-lagged reciprocal psychological empowerment-performance relationships.

    Science.gov (United States)

    Maynard, M Travis; Luciano, Margaret M; D'Innocenzo, Lauren; Mathieu, John E; Dean, Matthew D

    2014-11-01

    Employee psychological empowerment is widely accepted as a means for organizations to compete in increasingly dynamic environments. Previous empirical research and meta-analyses have demonstrated that employee psychological empowerment is positively related to several attitudinal and behavioral outcomes including job performance. While this research positions psychological empowerment as an antecedent influencing such outcomes, a close examination of the literature reveals that this relationship is primarily based on cross-sectional research. Notably, evidence supporting the presumed benefits of empowerment has failed to account for potential reciprocal relationships and endogeneity effects. Accordingly, using a multiwave, time-lagged design, we model reciprocal relationships between psychological empowerment and job performance using a sample of 441 nurses from 5 hospitals. Incorporating temporal effects in a staggered research design and using structural equation modeling techniques, our findings provide support for the conventional positive correlation between empowerment and subsequent performance. Moreover, accounting for the temporal stability of variables over time, we found support for empowerment levels as positive influences on subsequent changes in performance. Finally, we also found support for the reciprocal relationship, as performance levels were shown to relate positively to changes in empowerment over time. Theoretical and practical implications of the reciprocal psychological empowerment-performance relationships are discussed. (PsycINFO Database Record (c) 2014 APA, all rights reserved).

  7. Five year old preschoolers’ sharing is influenced by anticipated reciprocation

    Directory of Open Access Journals (Sweden)

    Mingrui eXiong

    2016-03-01

    Full Text Available Whether children share in anticipation of future benefits returned by a partner is an interesting question. In this study, 5-year-old children and an adult partner played a sharing game, in which children donated first and the partner donated afterward. In Experiment 1, the partner’s resources were more attractive than the child’s. In the reciprocal condition, the child was told that s/he would be a recipient when the partner played as a donor. In the nonreciprocal condition, however, the child was told that an anonymous child would be the recipient when the partner donated. Results showed that children shared more with the partner when they knew that they would be a recipient later. In Experiment 2, the child was always the recipient when the partner donated, but the partner’s resources were more desirable than the child’s in the high-value condition, and less desirable in the low-value condition. We found that children were more generous when the partner’s resources were valued higher. These findings demonstrate that 5-year-old preschoolers’ sharing choices take into account the anticipated reciprocity of the recipient, suggesting either self-interested tactical sharing or direct reciprocity in advance of receiving. Specifically, they adjust their sharing behavior depending on whether a partner has the potential to reciprocate, and whether it is worth sharing relative to the value of the payback.

  8. Reciprocity in International Affairs: An Analysis of Nigeria/South ...

    African Journals Online (AJOL)

    DrNneka

    2012-03-07

    Mar 7, 2012 ... Key Words: Reciprocity, International, Affairs, Diplomatic face-off, Nigeria, South. Africa. Introduction .... continuously on any other grounds than national interest… they have no right to do so being agents not ..... unfair treatment meted to her citizens by South Africans that is new (Kayode, 2012). This attitude ...

  9. The Reciprocal Organization of Constructive Activity in Drug Addiction

    Science.gov (United States)

    Akhmetzyanova, Anna I.; Nikishina, Vera B.; Klyueva, Nadezhda V.; Petrash, Ekaterina A.

    2016-01-01

    The urgency of the problem stated in the article is caused by the fact that modern scientific studies show that sustainable neuro-associative connections with the object of addiction arise at chemical addiction. The aim of this study is to examine the features of the reciprocal organization of constructive activities in drug addiction. Study of…

  10. Effects of Reciprocal Peer Guidance on Adolescents' Attitudes to ...

    African Journals Online (AJOL)

    This study sought to determine the effects of Reciprocal Peer Guidance (RPG) on students' attitudes to family responsibilities. ... Based on these findings, it was recommended that to enhance positive students' attitudes to family responsibilities, peer-based guidance strategies such as RPG should be adopted in addition to ...

  11. Does theorizing on reciprocal altruism apply to the relationships of individuals with a spinal cord injury?

    Science.gov (United States)

    Buunk, A P; Zurriaga, Rosario; González, Pilar

    2012-12-20

    From the perspective of reciprocal altruism, we examined the role of reciprocity in the close relationships of people inflicted with a spinal cord injury (SCI) (n = 70). We focused on the help receiver rather than on the help giver. Participants perceived more reciprocity in relationships with friends than in relationships with the partner and with family members. In these last relationships, perceptions of indebtedness were more prevalent than perceptions of deprivation. However, most negative feelings were evoked by a lack of reciprocity in partner relationships, followed by family relationships, and next by friendships. Moreover, depression was especially associated with a lack of perceived reciprocity in the relationships with family, and somewhat less with a lack of perceived reciprocity in the relationship with the partner. These results underline the importance of reciprocity in relationships, but suggest that reciprocity may be more, rather than less important in partner and family relationships.

  12. The Effect of Chemical Composition on Microstructure and Properties of Intercritically Reheated Coarse-Grained Heat-Affected Zone in X70 Steels

    Science.gov (United States)

    Zhu, Zhixiong; Kuzmikova, Lenka; Li, Huijun; Barbaro, Frank

    2013-12-01

    The current study investigates the effect of different levels of Ti, N, and Ti/N ratios on microstructure and properties in the intercritically reheated coarse-grained heat-affected zone (ICCGHAZ) of two-pass submerged arc welds in API 5L grade X70 pipe. Gleeble simulation was employed to reproduce the ICCGHAZ of actual welds. Hardness and Charpy V-notch (CVN) tests were performed on the simulated samples. The microstructure of simulated ICCGHAZ was characterized by optical microscopy and scanning electron microscopy (SEM). LePera color etching technique was employed to identify and quantify the martensitic-austenitic (M-A) constituent. Results show that the simulated ICCGHAZ exhibited extremely low toughness, but in the studied range of Ti and N, there was no correlation with Ti/N ratio. The beneficial effect of near-stoichiometric Ti/N ratio observed in coarse-grained heat-affected zone (CGHAZ) did not translate to ICCGHAZ. This was because of the negative effect of the blocky M-A constituent formed on prior austenite grain boundaries.

  13. Femtosecond/Nanosecond dual-pulse orthogonal geometry plasma plume reheating for compositional analysis of ancient copper-based-alloy artworks

    Energy Technology Data Exchange (ETDEWEB)

    Santagata, A [CNR-IMIP, Sezione di Potenza, Zona Industriale di Tito Scalo, 85050 Tito Scalo (PZ) (Italy); De Giacomo, A [Universita degli Studi di Bari, Dip. Chimica, Via Orabona 4, 70126 Bari (Italy); De Pascale, O [CNR-IMIP, Sezione di Bari, Via Amendola 122/D, 70126 Bari (Italy); Dell' Aglio, M [CNR-IMIP, Sezione di Bari, Via Amendola 122/D, 70126 Bari (Italy); Teghil, R [Universita degli Studi della Basilicata, Dip. Chimica, Via N. Sauro 85, 85100 Potenza (Italy); De Bonis, A [Universita degli Studi della Basilicata, Dip. Chimica, Via N. Sauro 85, 85100 Potenza (Italy); Corrente, M [Soprintendenza Archeologica della Puglia, Corte Lamberti 3, 70122 Bari (Italy); Parisi, G P [CNR-IMIP, Sezione di Potenza, Zona Industriale di Tito Scalo, 85050 Tito Scalo (PZ) (Italy); Orlando, S [CNR-IMIP, Sezione di Potenza, Zona Industriale di Tito Scalo, 85050 Tito Scalo (PZ) (Italy)

    2007-04-15

    Plasma plume emission spectroscopy signals induced in air by 0.8 mJ of a femtosecond- Single Pulse (fs-SP) laser beam were enhanced by using an orthogonal geometry ns-reheating Dual Pulse (DP) configuration. The plasma plume temperatures of several copper-based-alloy standards and calibration curves of their Sn and Pb contents were conveyed. The resulting data showed an independence from the matrix composition so that, even for significant wt % variation of Sn and Pb, good linear regression coefficients could be obtained (0.99 for Sn and 0.98 for Pb). The DP configuration, here reported, using a low energy (0.8 mJ) of the fs ablating laser beam, was considered for determining the Sn and Pb elemental contents of ancient copper-based-alloy artwork fragments coming from the 'Canne della Battaglia' archaeological site of Minervino Murge (Apulia - South of Italy). The results showed that, even by employing this low energy of the fs laser, which did not cause any visible damage of the ancient samples, the DP configuration supplied large enhancements and very well resolved emission lines of spectra providing information about the Sn and Pb contents which could support archaeologists work.

  14. Warm dark matter via ultra-violet freeze-in: reheating temperature and non-thermal distribution for fermionic Higgs portal dark matter

    Energy Technology Data Exchange (ETDEWEB)

    McDonald, John [Dept. of Physics, University of Lancaster,Lancaster LA1 4YB (United Kingdom)

    2016-08-17

    Warm dark matter (WDM) of order keV mass may be able to resolve the disagreement between structure formation in cold dark matter simulations and observations. The detailed properties of WDM will depend upon its energy distribution, in particular how it deviates from the thermal distribution usually assumed in WDM simulations. Here we focus on WDM production via the Ultra-Violet (UV) freeze-in mechanism, for the case of fermionic Higgs portal dark matter ψ produced via the portal interaction ψ-barψH{sup †}H/Λ. We introduce a new method to simplify the computation of the non-thermal energy distribution of dark matter from freeze-in. We show that the non-thermal energy distribution from UV freeze-in is hotter than the corresponding thermal distribution and has the form of a Bose-Einstein distribution with a non-thermal normalization. The resulting range of dark matter fermion mass consistent with observations is 5–7 keV. The reheating temperature must satisfy T{sub R}≳120 GeV in order to account for the observed dark matter density when m{sub ψ}≈5 keV, where the lower bound on T{sub R} corresponds to the limit where the fermion mass is entirely due to electroweak symmetry breaking via the portal interaction. The corresponding bound on the interaction scale is Λ≳6.0×10{sup 9} GeV.

  15. Operating results of 700MW coal fired supercritical once-through steam generator for Hekinan power station No.3 boiler, Chubu Electric Power Co. Inc. with elevated reheat steam temperature of 596{degree}C

    Energy Technology Data Exchange (ETDEWEB)

    Ando, S.; Ozawa, M.; Yamamoto, T.; Kuwahara, M. [Ishikawajima-Harima Heavy Indutries Co. Ltd., Tokyo (Japan)

    1995-01-01

    The demonstration test results of the 700 MW coal fired supercritical once-through steam generator for Hekinan Power Station, Chubu Electric Power Co., Inc. were reported which generator is featured by highest reheat steam temperature of 596{degree}C among commercial boilers. On static characteristics, both gross and net thermal efficiencies were higher than the design values in a load range of 30-100%, and higher by nearly 1% than those under conventional steam conditions. The metal temperature distribution of each portion was desirable, and the reheater could be well regulated below 610{degree}C lower than the design value (619{degree}C) without arrival on the alarm setting (650{degree}C). The load change of 5%/min in a high load zone and 3%/min in a low one was allowable for each coal type keeping stable steam temperature. Unburned carbon contents in fly ash was less than 2%, while NOx emission was less than 150 ppm at a boiler outlet. In addition, the unit start characteristics equivalent to those of oil fired boilers were obtained proving the possible boiler technology at 596{degree}C in reheater steam temperature. 7 figs.

  16. Transcranial Electrical Neuromodulation Based on the Reciprocity Principle.

    Science.gov (United States)

    Fernández-Corazza, Mariano; Turovets, Sergei; Luu, Phan; Anderson, Erik; Tucker, Don

    2016-01-01

    A key challenge in multi-electrode transcranial electrical stimulation (TES) or transcranial direct current stimulation (tDCS) is to find a current injection pattern that delivers the necessary current density at a target and minimizes it in the rest of the head, which is mathematically modeled as an optimization problem. Such an optimization with the Least Squares (LS) or Linearly Constrained Minimum Variance (LCMV) algorithms is generally computationally expensive and requires multiple independent current sources. Based on the reciprocity principle in electroencephalography (EEG) and TES, it could be possible to find the optimal TES patterns quickly whenever the solution of the forward EEG problem is available for a brain region of interest. Here, we investigate the reciprocity principle as a guideline for finding optimal current injection patterns in TES that comply with safety constraints. We define four different trial cortical targets in a detailed seven-tissue finite element head model, and analyze the performance of the reciprocity family of TES methods in terms of electrode density, targeting error, focality, intensity, and directionality using the LS and LCMV solutions as the reference standards. It is found that the reciprocity algorithms show good performance comparable to the LCMV and LS solutions. Comparing the 128 and 256 electrode cases, we found that use of greater electrode density improves focality, directionality, and intensity parameters. The results show that reciprocity principle can be used to quickly determine optimal current injection patterns in TES and help to simplify TES protocols that are consistent with hardware and software availability and with safety constraints.

  17. Final Report: Modifications and Optimization of the Organic Rankine Cycle to Improve the Recovery of Waste Heat

    Energy Technology Data Exchange (ETDEWEB)

    Guillen, Donna Post [Idaho National Lab. (INL), Idaho Falls, ID (United States); Zia, Jalal [Idaho National Lab. (INL), Idaho Falls, ID (United States)

    2013-09-01

    This research and development (R&D) project exemplifies a shared public private commitment to advance the development of energy efficient industrial technologies that will reduce the U.S. dependence upon foreign oil, provide energy savings and reduce greenhouse gas emissions. The purpose of this project was to develop and demonstrate a Direct Evaporator for the Organic Rankine Cycle (ORC) for the conversion of waste heat from gas turbine exhaust to electricity. In conventional ORCs, the heat from the exhaust stream is transferred indirectly to a hydrocarbon based working fluid by means of an intermediate thermal oil loop. The Direct Evaporator accomplishes preheating, evaporation and superheating of the working fluid by a heat exchanger placed within the exhaust gas stream. Direct Evaporation is simpler and up to 15% less expensive than conventional ORCs, since the secondary oil loop and associated equipment can be eliminated. However, in the past, Direct Evaporation has been avoided due to technical challenges imposed by decomposition and flammability of the working fluid. The purpose of this project was to retire key risks and overcome the technical barriers to implementing an ORC with Direct Evaporation. R&D was conducted through a partnership between the Idaho National Laboratory (INL) and General Electric (GE) Global Research Center (GRC). The project consisted of four research tasks: (1) Detailed Design & Modeling of the ORC Direct Evaporator, (2) Design and Construction of Partial Prototype Direct Evaporator Test Facility, (3) Working Fluid Decomposition Chemical Analyses, and (4) Prototype Evaluation. Issues pertinent to the selection of an ORC working fluid, along with thermodynamic and design considerations of the direct evaporator, were identified. The FMEA (Failure modes and effects analysis) and HAZOP (Hazards and operability analysis) safety studies performed to mitigate risks are described, followed by a discussion of the flammability analysis of the

  18. Comparison of a Novel Organic-Fluid Thermofluidic Heat Converter and an Organic Rankine Cycle Heat Engine

    Directory of Open Access Journals (Sweden)

    Christoph J.W. Kirmse

    2016-06-01

    Full Text Available The Up-THERM heat converter is an unsteady, two-phase thermofluidic oscillator that employs an organic working fluid, which is currently being considered as a prime-mover in small- to medium-scale combined heat and power (CHP applications. In this paper, the Up-THERM heat converter is compared to a basic (sub-critical, non-regenerative organic Rankine cycle (ORC heat engine with respect to their power outputs, thermal efficiencies and exergy efficiencies, as well as their capital and specific costs. The study focuses on a pre-specified Up-THERM design in a selected application, a heat-source temperature range from 210 °C to 500 °C and five different working fluids (three n-alkanes and two refrigerants. A modeling methodology is developed that allows the above thermo-economic performance indicators to be estimated for the two power-generation systems. For the chosen applications, the power output of the ORC engine is generally higher than that of the Up-THERM heat converter. However, the capital costs of the Up-THERM heat converter are lower than those of the ORC engine. Although the specific costs (£/kW of the ORC engine are lower than those of the Up-THERM converter at low heat-source temperatures, the two systems become progressively comparable at higher temperatures, with the Up-THERM heat converter attaining a considerably lower specific cost at the highest heat-source temperatures considered.

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

    Directory of Open Access Journals (Sweden)

    Sneade Mary

    2010-09-01

    Full Text Available Abstract 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

  20. Some properties of generalized self-reciprocal polynomials over finite fields

    Directory of Open Access Journals (Sweden)

    Ryul Kim

    2014-07-01

    Full Text Available Numerous results on self-reciprocal polynomials over finite fields have been studied. In this paper we generalize some of these to a-self reciprocal polynomials defined in [4]. We consider some properties of the divisibility of a-reciprocal polynomials and characterize the parity of the number of irreducible factors for a-self reciprocal polynomials over finite fields of odd characteristic.

  1. Reciprocity in Interaction: A Window on the First Year of Life in Autism

    OpenAIRE

    Fabio Apicella; Natasha Chericoni; Valeria Costanzo; Sara Baldini; Lucia Billeci; David Cohen; Filippo Muratori

    2013-01-01

    From early infancy onwards, young children appear motivated to engage reciprocally with others and share psychological states during dyadic interactions. Although poor reciprocity is one of the defining features of autism spectrum disorders (ASDs), few studies have focused on the direct assessment of real-life reciprocal behavior; consequently, our knowledge of the nature and the development of this core feature of autism is still limited. In this study, we describe the phenomenon of reciproc...

  2. The Effect of Reciprocal Peer Tutoring and Non-Reciprocal Peer Tutoring on the Performance of Students in College Physics

    Science.gov (United States)

    Dioso-Henson, Luzale

    2012-01-01

    Formalised peer-to-peer collaboration and the use of web-enhanced materials that are consistent with course objectives, graded assessments and learning outcomes is well known in educational practice. This study compared the academic gains of college students enrolled in Physics using Reciprocal Peer Tutoring (RPT) with others using non-Reciprocal…

  3. Lack of reciprocity among Dutch teachers: Validation of reciprocity indices and their relation to stress and well-being

    NARCIS (Netherlands)

    Horn, J.E. van; Schaufeli, W.B.; Taris, T.W.

    2001-01-01

    This research presents the results of two related studies on the convergent and construct validity of three measures of reciprocity in exchange relationships at work. In Study 1, 71 Dutch teachers were interviewed about their specific investments and outcomes in the exchange relationships with their

  4. 14 CFR 121.181 - Airplanes: Reciprocating engine-powered: En route limitations: One engine inoperative.

    Science.gov (United States)

    2010-01-01

    ... 14 Aeronautics and Space 3 2010-01-01 2010-01-01 false Airplanes: Reciprocating engine-powered: En... OPERATIONS Airplane Performance Operating Limitations § 121.181 Airplanes: Reciprocating engine-powered: En... person operating a reciprocating engine powered airplane may take off that airplane at a weight, allowing...

  5. 14 CFR 121.331 - Supplemental oxygen requirements for pressurized cabin airplanes: Reciprocating engine powered...

    Science.gov (United States)

    2010-01-01

    ... pressurized cabin airplanes: Reciprocating engine powered airplanes. 121.331 Section 121.331 Aeronautics and... pressurized cabin airplanes: Reciprocating engine powered airplanes. (a) When operating a reciprocating engine powered airplane pressurized cabin, each certificate holder shall equip the airplane to comply with...

  6. Does Theorizing on Reciprocal Altruism Apply to the Relationships of Individuals with a Spinal Cord Injury?

    NARCIS (Netherlands)

    Buunk, A. P.; Zurriaga, Rosario; Gonzalez, Pilar

    2012-01-01

    From the perspective of reciprocal altruism, we examined the role of reciprocity in the close relationships of people inflicted with a spinal cord injury (SCI) (n = 70). We focused on the help receiver rather than on the help giver. Participants perceived more reciprocity in relationships with

  7. Correlation between reciprocal changes in eletrocardiogram of the patients with acute myocardial infarction and involvement of coronary artery that perfuse area of myocardium related to reciprocal changes

    Directory of Open Access Journals (Sweden)

    Nematipour E

    2002-08-01

    Full Text Available Introduction: Reciprocal changes are ST depression ≥1 mm in electrocardiogram of the patients with acute myocardial infarction in the reciprocal leads. This question that these changes are merely secondary to ST elevation in infarction area or that they are truly subendocardial ischemia secondary to involvement of coronary artery that perfuse that area is not clearly defined. Methods and Materials: In this study, 33 patients with acute myocardial infarction and reciprocal changes in ECG at the time of admission, were selected and coronary angiography was performed in them in a week of infarction. Results: Correlation between reciprocal changes in ECG and involvement of reciprocal coronary artery the coronary artery that perfuse area of myocardium related to reciprocal changes in ECG were studied. 32-63 percent of patients (1/3-2/3 with reciprocal changes had significant stenosis of reciprocal coronary artery in coronary angiography (CI=95 percent. The incidence of multivessel disease was about 60.6 percent. After coronary angiography 33.3 percent of patients referred for coronary arteries bypass graft surgery (CABGS and 27.3 percent for percutaneous transluminal coronary artery angioplasty (PTCA. In the other words, 60.6 percent of our patients refered for revascularization, PTCA or CABGS. Conclusion: We concluded that because of the need for intervention in about 60 percent of our patients, coronary angiography could be recommended in all patients with acute myocardial infarction and reciprocal changes in ECG.

  8. Fault detection in reciprocating compressor valves under varying load conditions

    Science.gov (United States)

    Pichler, Kurt; Lughofer, Edwin; Pichler, Markus; Buchegger, Thomas; Klement, Erich Peter; Huschenbett, Matthias

    2016-03-01

    This paper presents a novel approach for detecting cracked or broken reciprocating compressor valves under varying load conditions. The main idea is that the time frequency representation of vibration measurement data will show typical patterns depending on the fault state. The problem is to detect these patterns reliably. For the detection task, we make a detour via the two dimensional autocorrelation. The autocorrelation emphasizes the patterns and reduces noise effects. This makes it easier to define appropriate features. After feature extraction, classification is done using logistic regression and support vector machines. The method's performance is validated by analyzing real world measurement data. The results will show a very high detection accuracy while keeping the false alarm rates at a very low level for different compressor loads, thus achieving a load-independent method. The proposed approach is, to our best knowledge, the first automated method for reciprocating compressor valve fault detection that can handle varying load conditions.

  9. Reciprocity in Linear Deterministic Networks under Linear Coding

    CERN Document Server

    Raja, Adnan; Viswanath, Pramod

    2009-01-01

    The linear deterministic model has been used recently to get a first order understanding of many wireless communication network problems. In many of these cases, it has been pointed out that the capacity regions of the network and its reciprocal (where the communication links are reversed and the roles of the sources and the destinations are swapped) are the same. In this paper, we consider a linear deterministic communication network with multiple unicast information flows. For this model and under the restriction to the class of linear coding, we show that the rate regions for a network and its reciprocal are the same. This can be viewed as a generalization of the linear reversibility of wireline networks, already known in the network coding literature.

  10. Heat Transfer Simulation for Reciprocating Compressor with Experimental Validation

    Science.gov (United States)

    Zhou, Ruixin; Guo, Bei; Chen, Xiaole; Tuo, Jinliang; Wu, Rui; Fagotti, Fabian; Zhao, Yali; Yang, Song; Xu, Bo

    2017-08-01

    The efficiency of reciprocating compressor can be influenced by heat transfer and the reliability can be also affected by the temperature distribution in compressor. In consideration of the complex relationship of heat transfer, the compressor is divided into six control volumes including the suction muffler, the cylinder, the discharge chamber, the discharge muffler, the discharge line and the compressor shell. The steady state energy balance equations of the open system for each control volume are built up after the crankshaft rotates one cycle. The heat flux of the cylinder is calculated by the existing correlation. The heat transfer coefficient correlations in energy equations are chosen in references and revised by experimental results. Three same type reciprocating compressors used in R290 system installed with themocouples are tested under some planed conditions in order to ensure accuracy. The simulation results are compared with the experimental results. It shows that the simplified method presented in this paper is effective.

  11. Intimate Partner Violence: A Rare Case of Reciprocal Homicide.

    Science.gov (United States)

    Cauchois, Aurélie; Paraire, François; Lorin de la Grandmaison, Geoffroy

    2017-06-01

    We present the case of a reciprocal homicide by stabbing that occurred within an unmarried couple without known history of spousal violence. Each partner killed the other one at the same time and at the same place using kitchen knives. They were both found dead at home lying on the floor after the neighbors heard an argument and screams coming from the couple's apartment, so they called the police and the fire department. The door was locked from the inside, and the fire department was forced to break the door. Two kitchen knives supporting blood traces were found at the scene. At autopsy, both bodies showed multiple stab wounds, and the lethal ones were due to heart injuries. Defense injuries were also found in both bodies. To our knowledge, this is the first case of reciprocal homicide described in the literature. Other manners of death are discussed, including homicide by a third party, homicide-suicide, and suicide pact.

  12. Indirect Reciprocity with Optional Interactions and Private Information

    Directory of Open Access Journals (Sweden)

    Jason Olejarz

    2015-09-01

    Full Text Available We consider indirect reciprocity with optional interactions and private information. A game is offered between two players and accepted unless it is known that the other person is a defector. Whenever a defector manages to exploit a cooperator, his or her reputation is revealed to others in the population with some probability. Therefore, people have different private information about the reputation of others, which is a setting that is difficult to analyze in the theory of indirect reciprocity. Since a defector loses a fraction of his social ties each time he exploits a cooperator, he is less efficient at exploiting cooperators in subsequent rounds. We analytically calculate the critical benefit-to-cost ratio above which cooperation is successful in various settings. We demonstrate quantitative agreement with simulation results of a corresponding Wright–Fisher process with optional interactions and private information. We also deduce a simple necessary condition for the critical benefit-to-cost ratio.

  13. Egocentric reciprocity and the role of friendship and anger.

    Science.gov (United States)

    Chen, Xiao-Ping; Eberly, Marion B; Bachrach, Daniel G; Wu, Keke; Qu, Qing

    2017-01-01

    In this research, we examine the phenomenon of egocentric reciprocity, where individuals protect self-interest by adopting an eye-for-an-eye strategy in negatively imbalanced exchanges, and by taking advantage of overly generous treatment in positively imbalanced exchanges. We conducted two experiments using a modified ultimatum game examining attitudinal and behavioral responses to imbalanced exchanges. The experiments allowed us to explore the moderating role of relational closeness (i.e., whether the game partner was a friend or a stranger) and the mediating role of anger and indebtedness in these moderated relationships. Our results consistently demonstrate the phenomenon of egocentric reciprocity. Most importantly, this research reveals that friendship places a boundary on this egocentric tendency, and that the effects may partially be explained by anger experienced in response to exchange.

  14. Balanced reciprocal translocation 5,18: a case report

    Directory of Open Access Journals (Sweden)

    Shahram Savad

    2014-05-01

    Conclusion: A balanced reciprocal translocation carrier is phenotypically normal, but during meiosis І, carrier chromosomes cant pair normally and form quadrivalant instead of bivalant that depend on type of their segregation (alternate, adjacent 1, adjacent 2,3:1,4:0, produce gametes that are chromosomally unbalanced which can result in early fetus abortion. Considering the number of abnormal gametes, the most effective way to help couples with this problem seems to be PGD 24sure, since it can identify reciprocal and Robertsonian translocation and allows concurrent screening of all chromosomes for aneuploidy. Another technique that can be compared with PGD 24sure is fluorescence in situ hybridization (FISH, but it has several technical limitations such as it is expensive and complexity, in addition it has only few probes (for chromosomes 21, 13, 18, X, Y so sometimes necessary to create patient specific protocols.

  15. Modified condylotomy versus conventional conservative treatment in painful reciprocal clicking

    DEFF Research Database (Denmark)

    Bakke, Merete; Eriksson, Lars; Thorsen, Niels Max

    2008-01-01

    Modified condylotomy may be relevant in severe painful reciprocal clicking of the temporomandibular joint (TMJ) where conservative treatment is insufficient. The effect of the modified condylotomy was analyzed and compared with conventional nonsurgical treatment in a randomized pilot study of eight...... patients, 19-44 years of age, with severe painful reciprocal clicking. Before and after treatment, assessments were performed by subjective reports, clinical recordings, and blinded evaluations of radiography and magnetic resonance imaging (MRI). Based on the clinical evaluations before treatment, all...... conditions were disc displacements with reduction and arthralgia (Research diagnostic criteria for temporomandibular disorders), but based on MRI, one patient had disc displacement without reduction and another had normal disc position. The treatment effect was significantly better and the disorders were...

  16. Experience sharing, emotional reciprocity, and turn-taking

    Directory of Open Access Journals (Sweden)

    Melisa eStevanovic

    2015-04-01

    Full Text Available In this perspective article, we consider the relationship between experience sharing and turn-taking. There is much evidence suggesting that human social interaction is permeated by two temporal organizations: (1 the sequential framework of turn-taking and (2 the concurrent framework of emotional reciprocity. From this perspective, we introduce two alternative hypotheses about how the relationship between experience sharing and turn-taking could be viewed. According to the first hypothesis, the home environment of experience sharing is in the concurrent framework of emotional reciprocity, while the motivation to share experiences is in tension with the sequential framework of turn-taking. According to the second hypothesis, then again, people’s inclination to coordinate their actions in terms of turn-taking is motivated precisely by their propensity to share experiences. We consider theoretical and empirical ideas in favor of both of these hypotheses and discuss their implications for future research.

  17. Reciprocal Modulation of Cognitive and Emotional Aspects in Pianistic Performances

    OpenAIRE

    Marcia K Kodama Higuchi; José Fornari; Del Ben, Cristina M.; Graeff, Frederico G; João Pereira Leite

    2011-01-01

    Background: High level piano performance requires complex integration of perceptual, motor, cognitive and emotive skills. Observations in psychology and neuroscience studies have suggested reciprocal inhibitory modulation of the cognition by emotion and emotion by cognition. However, it is still unclear how cognitive states may influence the pianistic performance. The aim of the present study is to verify the influence of cognitive and affective attention in the piano performances. Methods an...

  18. Reciprocal engagement between a scientist and visual displays

    OpenAIRE

    Nolasco, Michelle Maria

    2012-01-01

    In this study the focus of investigation was the reciprocal engagement between a professional scientist and the visual displays with which he interacted. Visual displays are considered inextricable from everyday scientific endeavors and their interpretation requires a "back-and-forthness" between the viewers and the objects being viewed. The query that drove this study was : How does a scientist engage with visual displays during the explanation of his understanding of extremely small biologi...

  19. An Examination of Reciprocal Influences in Sport Socialization

    OpenAIRE

    海老原, 修; 横山, 文人; 宮下, 充正

    1989-01-01

    This study was designed to clarify reciprocal influences in sport socialization. Parent-effects were assessed by their sport involvement before their child participated in organized sport, whereas child-effects were measured by a parent's attitudinal and behavioral changes of sport involvement caused by a child's participation. Eight indicators of sport involvement were selected as follows: 3 types of interest in sport involvement such as activities, sport consumption, and sport activity in o...

  20. Novel Long Stroke Reciprocating Compressor for Energy Efficient Jaggery Making

    Science.gov (United States)

    Rane, M. V.; Uphade, D. B.

    2017-08-01

    Novel Long Stroke Reciprocating Compressor is analysed for jaggery making while avoiding burning of bagasse for concentrating juice. Heat of evaporated water vapour along with small compressor work is recycled to enable boiling of juice. Condensate formed during heating of juice is pure water, as oil-less compressor is used. Superheat of compressor is suppressed by flow of superheated vapours through condensate. It limits heating surface temperature and avoids caramelization of sugar. Thereby improves quality of jaggery and eliminates need to use chemicals for colour improvement. Stroke to bore ratio is 0.6 to 1.2 in conventional reciprocating drives. Long stroke in reciprocating compressors enhances heat dissipation to surrounding by providing large surface area and increases isentropic efficiency by reducing compressor outlet temperature. Longer stroke increases inlet and exit valve operation timings, which reduces inertial effects substantially. Thereby allowing use of sturdier valves. This enables handling liquid along with vapour in compressors. Thereby supressing the superheat and reducing compressor power input. Longer stroke increases stroke to clearance ratios which increases volumetric efficiency and ability of compressor to compress through higher pressure ratios efficiently. Stress-strain simulation is performed in SolidWorks for gear drive. Long Stroke Reciprocating Compressor is developed at Heat Pump Laboratory, stroke/bore 292 mm/32 mm. It is operated and tested successfully at different speeds for operational stability of components. Theoretical volumetric efficiency is 93.9% at pressure ratio 2.0. Specific energy consumption is 108.3 kWhe/m3 separated water, considering free run power.

  1. Microscopic Perspective on Photovoltaic Reciprocity in Ultrathin Solar Cells.

    Science.gov (United States)

    Aeberhard, Urs; Rau, Uwe

    2017-06-16

    The photovoltaic reciprocity theory relates the electroluminescence spectrum of a solar cell under applied bias to the external photovoltaic quantum efficiency of the device as measured at short circuit conditions. Its derivation is based on detailed balance relations between local absorption and emission rates in optically isotropic media with nondegenerate quasiequilibrium carrier distributions. In many cases, the dependence of density and spatial variation of electronic and optical device states on the point of operation is modest and the reciprocity relation holds. In nanostructure-based photovoltaic devices exploiting confined modes, however, the underlying assumptions are no longer justifiable. In the case of ultrathin absorber solar cells, the modification of the electronic structure with applied bias is significant due to the large variation of the built-in field. Straightforward use of the external quantum efficiency as measured at short circuit conditions in the photovoltaic reciprocity theory thus fails to reproduce the electroluminescence spectrum at large forward bias voltage. This failure is demonstrated here by numerical simulation of both spectral quantities at normal incidence and emission for an ultrathin GaAs p-i-n solar cell using an advanced quantum kinetic formalism based on nonequilibrium Green's functions of coupled photons and charge carriers. While coinciding with the semiclassical relations under the conditions of their validity, the theory provides a consistent microscopic relationship between absorption, emission, and charge carrier transport in photovoltaic devices at arbitrary operating conditions and for any shape of optical and electronic density of states.

  2. Evaluation of cutting ability and plastic deformation of reciprocating files

    Directory of Open Access Journals (Sweden)

    Alexandre KOWALCZUCK

    2016-01-01

    Full Text Available Abstract This in vitro study evaluated the cutting ability of reciprocating files and the deformations caused by their multiple use. Five Reciproc® R25 files were divided into five groups for 10 simulated root canal preparations each. The resin blocks were weighed and photographed (12.5X and 20X before and after preparation. The canals were prepared according to the manufacturer’s instructions. Enlargement of the root canals was evaluated by comparison of pre- and post-preparation images using a computer software. The preoperative and postoperative weight differences determined the cutting ability of repeatedly used instruments. The data were analyzed using Lilliefors and Friedman statistical tests. The cutting ability and enlargement of the canals gradually decreased after each use, with significant differences observed at the 8th and 9th repetitions, respectively. There was no evidence of file deformation. The cutting ability and enlargement of the simulated canals gradually decreased when a reciprocating file was used up to 10 times.

  3. Reciprocity and the Emergence of Power Laws in Social Networks

    Science.gov (United States)

    Schnegg, Michael

    Research in network science has shown that many naturally occurring and technologically constructed networks are scale free, that means a power law degree distribution emerges from a growth model in which each new node attaches to the existing network with a probability proportional to its number of links (= degree). Little is known about whether the same principles of local attachment and global properties apply to societies as well. Empirical evidence from six ethnographic case studies shows that complex social networks have significantly lower scaling exponents γ ~ 1 than have been assumed in the past. Apparently humans do not only look for the most prominent players to play with. Moreover cooperation in humans is characterized through reciprocity, the tendency to give to those from whom one has received in the past. Both variables — reciprocity and the scaling exponent — are negatively correlated (r = -0.767, sig = 0.075). If we include this effect in simulations of growing networks, degree distributions emerge that are much closer to those empirically observed. While the proportion of nodes with small degrees decreases drastically as we introduce reciprocity, the scaling exponent is more robust and changes only when a relatively large proportion of attachment decisions follow this rule. If social networks are less scale free than previously assumed this has far reaching implications for policy makers, public health programs and marketing alike.

  4. Reciprocal burnout model: Interconnectedness of interpersonal and intrapersonal factors

    Directory of Open Access Journals (Sweden)

    Andreja Pšeničny

    2007-01-01

    Full Text Available Burnout can be described as chronic state of extreme psychophysical and emotional exhaustion. Burning out is a stage process consisting of: the stage of exhaustion, the stage of captivity and the final stage – adrenal burnout. Adrenal burnout syndrome (ABS is the final stage of burning out process, resulting in a functional blocade of hypothalamic-pituitary-adrenal axis which causes secondary cortisol insufficiency. Even though they share similar symptoms, burnout and depression are two different types of disorder. They differ mainly in basic cortisol levels and self-esteem. Researchers tend to link the burnout syndrome and environmental stress (interpersonal causes. Recently, some of them found connection between burnout syndrome and personality traits (intrapersonal causes. Reciprocal burnout model links both causes. It shows that in the same circumstances only a few people suffer from adrenal burnout syndrome. It states that personal characteristics are one of the main causes why people suffering from burnout syndrome enroll in nonreciprocal personal and professional relations. Socialization process plays an important role in development of personality traits. The core of the reciprocal burnout model consists of one's attitude towards his or her basic needs' fulfillment, personal system of values, and correlation between fulfillment of basic needs (energy accumulation and burning out process (energy consumption. Reciprocal burnout model is opening a series of questions, concerning the connection between personality traits, life satisfaction and personal values, and burnout syndrome risk behavior, as well as the influence of whole life circumstances on burning out process.

  5. A reciprocal framework for spatial K-anonymity

    KAUST Repository

    Ghinita, Gabriel

    2010-05-01

    Spatial K-anonymity (SKA) exploits the concept of K-anonymity in order to protect the identity of users from location-based attacks. The main idea of SKA is to replace the exact location of a user U with an anonymizing spatial region (ASR) that contains at least K-1 other users, so that an attacker can pinpoint U with probability at most 1/K. Simply generating an ASR that includes K users does not guarantee SKA. Previous work defined the reciprocity property as a sufficient condition for SKA. However, the only existing reciprocal method, Hilbert Cloak, relies on a specialized data structure. In contrast, we propose a general framework for implementing reciprocal algorithms using any existing spatial index on the user locations. We discuss ASR construction methods with different tradeoffs on effectiveness (i.e., ASR size) and efficiency (i.e., construction cost). Then, we present case studies of applying our framework on top of two popular spatial indices (namely, R*-trees and Quad-trees). Finally, we consider the case where the attacker knows the query patterns of each user. The experimental results verify that our methods outperform Hilbert Cloak. Moreover, since we employ general-purpose spatial indices, the proposed system is not limited to anonymization, but supports conventional spatial queries as well. © 2009 Elsevier B.V. All rights reserved.

  6. Magneto-optical non-reciprocal devices in silicon photonics

    Directory of Open Access Journals (Sweden)

    Yuya Shoji

    2014-01-01

    Full Text Available Silicon waveguide optical non-reciprocal devices based on the magneto-optical effect are reviewed. The non-reciprocal phase shift caused by the first-order magneto-optical effect is effective in realizing optical non-reciprocal devices in silicon waveguide platforms. In a silicon-on-insulator waveguide, the low refractive index of the buried oxide layer enhances the magneto-optical phase shift, which reduces the device footprints. A surface activated direct bonding technique was developed to integrate a magneto-optical garnet crystal on the silicon waveguides. A silicon waveguide optical isolator based on the magneto-optical phase shift was demonstrated with an optical isolation of 30 dB and insertion loss of 13 dB at a wavelength of 1548 nm. Furthermore, a four port optical circulator was demonstrated with maximum isolations of 15.3 and 9.3 dB in cross and bar ports, respectively, at a wavelength of 1531 nm.

  7. The evolution of conditional moral assessment in indirect reciprocity

    Science.gov (United States)

    Sasaki, Tatsuya; Okada, Isamu; Nakai, Yutaka

    2017-02-01

    Indirect reciprocity is a major mechanism in the maintenance of cooperation among unrelated individuals. Indirect reciprocity leads to conditional cooperation according to social norms that discriminate the good (those who deserve to be rewarded with help) and the bad (those who should be punished by refusal of help). Despite intensive research, however, there is no definitive consensus on what social norms best promote cooperation through indirect reciprocity, and it remains unclear even how those who refuse to help the bad should be assessed. Here, we propose a new simple norm called “Staying” that prescribes abstaining from assessment. Under the Staying norm, the image of the person who makes the decision to give help stays the same as in the last assessment if the person on the receiving end has a bad image. In this case, the choice about whether or not to give help to the potential receiver does not affect the image of the potential giver. We analyze the Staying norm in terms of evolutionary game theory and demonstrate that Staying is most effective in establishing cooperation compared to the prevailing social norms, which rely on constant monitoring and unconditional assessment. The application of Staying suggests that the strict application of moral judgment is limited.

  8. Microscopic Perspective on Photovoltaic Reciprocity in Ultrathin Solar Cells

    Science.gov (United States)

    Aeberhard, Urs; Rau, Uwe

    2017-06-01

    The photovoltaic reciprocity theory relates the electroluminescence spectrum of a solar cell under applied bias to the external photovoltaic quantum efficiency of the device as measured at short circuit conditions. Its derivation is based on detailed balance relations between local absorption and emission rates in optically isotropic media with nondegenerate quasiequilibrium carrier distributions. In many cases, the dependence of density and spatial variation of electronic and optical device states on the point of operation is modest and the reciprocity relation holds. In nanostructure-based photovoltaic devices exploiting confined modes, however, the underlying assumptions are no longer justifiable. In the case of ultrathin absorber solar cells, the modification of the electronic structure with applied bias is significant due to the large variation of the built-in field. Straightforward use of the external quantum efficiency as measured at short circuit conditions in the photovoltaic reciprocity theory thus fails to reproduce the electroluminescence spectrum at large forward bias voltage. This failure is demonstrated here by numerical simulation of both spectral quantities at normal incidence and emission for an ultrathin GaAs p -i -n solar cell using an advanced quantum kinetic formalism based on nonequilibrium Green's functions of coupled photons and charge carriers. While coinciding with the semiclassical relations under the conditions of their validity, the theory provides a consistent microscopic relationship between absorption, emission, and charge carrier transport in photovoltaic devices at arbitrary operating conditions and for any shape of optical and electronic density of states.

  9. Nonreciprocal and Reciprocal Dating Violence and Injury Occurrence among Urban Youth

    Directory of Open Access Journals (Sweden)

    Swahn, Monica H

    2010-08-01

    Full Text Available Objective: Dating violence is a significant health problem among youth that leads to adverse health outcomes, including injuries. Reciprocal violence (perpetrated by both partners is associated with increased injury in adults, but very little is known about the prevalence and context for reciprocal violence, as well as injury rates, among youth. We sought to determine the prevalence and scope of reciprocal dating violence and injury occurrence among urban youth in a high-risk community. Methods: Analyses were based on data from the Youth Violence Survey, conducted in 2004, and administered to over 80% of public school students in grades 7, 9, 11, and 12 (N=4,131 in a high-risk, urban school district. The current analyses were restricted to those who reported dating in the past year and who also reported any dating violence (n=1,158. Dating violence was categorized as reciprocal (the participant reported both violence perpetration and victimization and non-reciprocal (the participant report either violence perpetration or victimization, but not both. Results: Dating violence reciprocity varied by sex. Girls who reported any dating violence were more likely to report reciprocal dating violence (50.4% than were boys (38.9%. However, reciprocity did not vary by race/ethnicity or grade level. Reciprocal dating violence was more common among participants who reported more frequent violence experiences. Reciprocal violence was also associated with greater injury occurrences relative to non-reciprocal relationships (10.1% versus 1.2%. Conclusion: Reciprocal dating violence is common among adolescents and leads more often to injury outcomes. In particular, relationships in which boys report reciprocal violence against their partner appear to lead to more frequent injury occurrences. These findings underscore the importance of addressing dating violence and factors that increase risk for reciprocal violence and therefore exacerbate injury occurrence

  10. Nonreciprocal and Reciprocal Dating Violence and Injury Occurrence among Urban Youth.

    Science.gov (United States)

    Swahn, Monica H; Alemdar, Meltem; Whitaker, Daniel J

    2010-08-01

    Dating violence is a significant health problem among youth that leads to adverse health outcomes, including injuries. Reciprocal violence (perpetrated by both partners) is associated with increased injury in adults, but very little is known about the prevalence and context for reciprocal violence, as well as injury rates, among youth. We sought to determine the prevalence and scope of reciprocal dating violence and injury occurrence among urban youth in a high-risk community. Analyses were based on data from the Youth Violence Survey, conducted in 2004, and administered to over 80% of public school students in grades 7, 9, 11, and 12 (N=4,131) in a high-risk, urban school district. The current analyses were restricted to those who reported dating in the past year and who also reported any dating violence (n=1,158). Dating violence was categorized as reciprocal (the participant reported both violence perpetration and victimization) and non-reciprocal (the participant report either violence perpetration or victimization, but not both). Dating violence reciprocity varied by sex. Girls who reported any dating violence were more likely to report reciprocal dating violence (50.4%) than were boys (38.9%). However, reciprocity did not vary by race/ethnicity or grade level. Reciprocal dating violence was more common among participants who reported more frequent violence experiences. Reciprocal violence was also associated with greater injury occurrences relative to non-reciprocal relationships (10.1% versus 1.2%). Reciprocal dating violence is common among adolescents and leads more often to injury outcomes. In particular, relationships in which boys report reciprocal violence against their partner appear to lead to more frequent injury occurrences. These findings underscore the importance of addressing dating violence and factors that increase risk for reciprocal violence and therefore exacerbate injury occurrence.

  11. Calculation of wave resistance by using Kochin function in the Rankine source method; Rankinsosuho ni okeru kochin kansu wo mochiita zoha teiko keisan

    Energy Technology Data Exchange (ETDEWEB)

    Yasukawa, H. [Mitsubishi Heavy Industries, Ltd., Tokyo (Japan)

    1997-10-01

    In order to avoid negative wave resistance (which is physically incomprehensible) generated in calculating wave resistance by using the Rankine source method, a proposal was made on a wave resistance calculation method using the Kochin function which describes behavior of speed potential in regions far apart from a hull. The Baba`s condition was used as a free surface condition for the speed potential which expresses wave motions around a hull. This has allowed a new Kochin function which uses as unknown the speed potential on the hull surface and the free surface near the hull to be defined and combined with the Rankine source method. A comparison was made between the calculated values for wave resistance, hull subsidence and trim change of an ore transporting vessel (SR107 type of ship) in a fully loaded condition and the result of water tank tests. The wave resistance values derived from pressure integration have all become negative when the Froude number is from 0.1 to 0.2, while no negative resistance has appeared in the calculations by using the Kochin function, but the result has agreed with that of the water tank tests. Accuracy of the calculations at low speeds was improved. The trim change in the calculations was slightly smaller than that in the water tank tests. The subsidence showed a good agreement. 7 refs., 1 fig.

  12. Performance improvement in thermal power plants. ; Design of 700MW coal-fired boiler with elevated reheat steam temperature for Hekinan No. 3 unit, Chubu Electric Power Co. Ltd. Karyoku hatsudensho no seino kojo taisaku. ; Chubu denryoku (kabu) Hekinan karyoku hatsudensho 3 go unit muke koon sainetsu joki ondo (596 degree C)saiyo boiler no keikaku

    Energy Technology Data Exchange (ETDEWEB)

    Kuwahara, M.; Kajigaya, I.; Umaki, H.; Kunihiro, T. (Ishikawajima-Harima Heavy Industries, Co. Ltd., Tokyo (Japan))

    1991-07-15

    The 700 MW coal fired super critical boiler with elevated reheat steam temperature for variable pressure operation was outlined which is under development for the Hekinan No. 3 unit, Chubu Electric Power Co., Inc. Its steam temperature was designed to be 596{degree}C at a reheater outlet and 593{degree}C at an intermediate pressure turbine inlet in the range from 35 to 100% of maximum continuous evaporation. For such high temperature steam conditions, the arrangement of reheater heating surfaces was optimized by examining both static and dynamic characteristics. Tubing materials for the reheater outlet were carefully selected in consideration of coal ash corrosion and steam side oxidation, and modified 9Cr-1Mo steel was widely adopted for high temperature parts. The seam-welded modified 9Cr-1Mo steel pipe was, in particular, adopted for hot reheat pipes, and the bending fabricability and weldability of such steel plate were tested extensively on a full-scale mock-up model to ensure a plant reliability. 1 ref., 15 figs., 4 tabs.

  13. Monkeys benefit from reciprocity without the cognitive burden

    Science.gov (United States)

    Suchak, Malini; de Waal, Frans B. M.

    2012-01-01

    The debate about the origins of human prosociality has focused on the presence or absence of similar tendencies in other species, and, recently, attention has turned to the underlying mechanisms. We investigated whether direct reciprocity could promote prosocial behavior in brown capuchin monkeys (Cebus apella). Twelve capuchins tested in pairs could choose between two tokens, with one being “prosocial” in that it rewarded both individuals (i.e., 1/1), and the other being “selfish” in that it rewarded the chooser only (i.e., 1/0). Each monkey’s choices with a familiar partner from their own group was compared with choices when paired with a partner from a different group. Capuchins were spontaneously prosocial, selecting the prosocial option at the same rate regardless of whether they were paired with an in-group or out-group partner. This indicates that interaction outside of the experimental setting played no role. When the paradigm was changed, such that both partners alternated making choices, prosocial preference significantly increased, leading to mutualistic payoffs. As no contingency could be detected between an individual’s choice and their partner’s previous choice, and choices occurred in rapid succession, reciprocity seemed of a relatively vague nature akin to mutualism. Having the partner receive a better reward than the chooser (i.e., 1/2) during the alternating condition increased the payoffs of mutual prosociality, and prosocial choice increased accordingly. The outcome of several controls made it hard to explain these results on the basis of reward distribution or learned preferences, and rather suggested that joint action promotes prosociality, resulting in so-called attitudinal reciprocity. PMID:22949668

  14. Small variable speed hermetic reciprocating compressors for domestic refrigerators

    DEFF Research Database (Denmark)

    Rasmussen, Bjarne D.

    1996-01-01

    This paper contains both a theoretical and experimental investigation of some of the fundamental characteristics of a smal variable speed hermetic reciprocating compressor intended for application in domestic refrigeration. The results of a previously published simulation model for variable speed...... compressors are compared with experimental results obtained in a compressor test bench. The influence of speed on compressor performance is discussed with focus on valve modelling and internal thermal phenomena. Further plans for development and validation of the model as well as experimental investigations...

  15. Necklaces, Self-Reciprocal Polynomials, and q-Cycles

    OpenAIRE

    Umarin Pintoptang; Vichian Laohakosol; Suton Tadee

    2014-01-01

    Let n≥2 be a positive integer and q a prime power. Consider necklaces consisting of n beads, each of which has one of the given q colors. A primitive Cn-orbit is an equivalence class of n necklaces closed under rotation. A Cn-orbit is self-complementary when it is closed under an assigned color matching. In the work of Miller (1978), it is shown that there is a 1-1 correspondence between the set of primitive, self-complementary Cn-orbits and that of self-reciprocal irreducible monic (srim) po...

  16. Reciprocity and Constructions of Informed Consent: Researching with Indigenous Populations

    Directory of Open Access Journals (Sweden)

    Jason Brent Ellis

    2006-12-01

    Full Text Available In this article, the authors present a discussion of institutional review boards and potential challenges qualitative researchers may face when presenting human subjects research proposals to these boards for approval. In particular, they focus on issues of consent and reciprocity with Indigenous populations, whose culture and traditions might be quite different from those review boards typically see. After presenting these issues, the authors close with a framework that can be used as a guide for ethical considerations in research with Indigenous peoples.

  17. Quantum reciprocity conjecture for the non-equilibrium steady state

    Energy Technology Data Exchange (ETDEWEB)

    Coleman, P; Mao, W [Center for Materials Theory, Rutgers University, Piscataway, NJ 08854 (United States)

    2004-05-26

    A consideration of the lack of history dependence in the non-equilibrium steady state of a quantum system leads us to conjecture that in such a system there is a set of quantum mechanical observables whose retarded response functions are insensitive to the arrow of time, and which consequently satisfy a quantum analogue of the Onsager reciprocity relations. Systems which satisfy this conjecture can be described by an effective free energy functional. We demonstrate that the conjecture holds in a resonant level model of a multi-lead quantum dot. (letter to the editor)

  18. Optimal contracts based on subjective performance evaluations and reciprocity

    DEFF Research Database (Denmark)

    Sebald, Alexander Christopher; Walzl, Markus

    2015-01-01

    As demonstrated in a recent laboratory experiment (see Sebald & Walzl, 2014), individuals tend to sanction others who subjectively evaluate their performance whenever this assessment falls short of the individuals’ self-evaluation. Interestingly, this is the case even if the individuals’ earnings...... are unaffected by the subjective performance appraisal. Hence, performance feedback which falls short of agents’ self- evaluations can be interpreted as an unkind act that triggers a negatively reciprocal response not only if the assessment determines agents’ earnings but also when it lacks monetary consequences...

  19. Breaking Lorentz Reciprocity with Frequency Conversion and Delay

    Science.gov (United States)

    Rosenthal, Eric I.; Chapman, Benjamin J.; Higginbotham, Andrew P.; Kerckhoff, Joseph; Lehnert, K. W.

    2017-10-01

    We introduce a method for breaking Lorentz reciprocity based upon the noncommutation of frequency conversion and delay. The method requires no magnetic materials or resonant physics, allowing for the design of scalable and broadband nonreciprocal circuits. With this approach, two types of gyrators—universal building blocks for linear, nonreciprocal circuits—are constructed. Using one of these gyrators, we create a circulator with >15 dB of isolation across the 5-9 GHz band. Our designs may be readily extended to any platform with suitable frequency conversion elements, including semiconducting devices for telecommunication or an on-chip superconducting implementation for quantum information processing.

  20. Subjective performance evaluations and reciprocity in principal-agent relations

    DEFF Research Database (Denmark)

    Sebald, Alexander Christopher; Walzl, Markus

    2014-01-01

    . In contrast to existing models of reciprocity, we find that agents tend to sanction whenever the feedback of principals is below their subjective self-evaluations even if agents' pay-offs are independent of it. In turn, principals provide more positive feedback (relative to their actual performance assessment......We conduct a laboratory experiment with agents working on, and principals benefiting from, a real effort task in which the agents' performance can only be evaluated subjectively. Principals give subjective performance feedback to agents, and agents have an opportunity to sanction principals...