bluuebunny/crossref_metadata_2025_split huggingface dataset:
Signaling Corporate Social Responsibility: Third‐Party Certification versus Brands
Authors: Etilé Fabrice , Teyssier Sabrina 
Published: October 2015

AbstractCorporate social responsibility (CSR) is a credence attribute of products, which can be signaled either through a label certified by a third party, or via unsubstantiated claims used as part of a brand‐building strategy. We use an experimental posted‐offer market with sellers and buyers to compare the impact of these signaling strategies on market efficiency. Only third‐party certification gives rise to a separating equilibrium and an increase in CSR investments. Unsubstantiated claims can generate a halo effect on consumers, whereby the latter are nudged into paying more for the same level of CSR investments by firms.
Modes of Supply for US Exports of Services
Authors: Christen Elisabeth , Francois Joseph 
Published: October 2015

AbstractWe examine the choice of modes of delivery in services based on US data, including both cross‐border exports and sales through foreign affiliates. We focus on characteristics of destination markets and how this impacts on mode choice. We find that market size, distance and policy all play a role in where firms establish, and in how many markets firms enter. The importance of sales through affiliates relative to total foreign sales also depends on factors like market size, geographic and economic distance and the policy regime in place. Precisely, how important these factors are depends on the sector in question.
The ‘intrusive as’‐construction in South Asian varieties of English
Authors: LANGE CLAUDIA 
Published: October 2015

ABSTRACTIt has been observed (Nihalani et al. 1979; Yadurajan 2001) that Indian English differs from other varieties of English in that it allows ‘intrusive as’ in complex‐transitive constructions, especially with the verbs call, name and term. However, the construction is not restricted to Indian English, but represents a pan‐South Asian feature that is gaining ground in the written language across South Asian varieties of English. This paper will provide a corpus‐based analysis of the forms, functions and distribution of ‘intrusive as’‐constructions in South Asian Englishes, and consider possible motivations for this innovation in verb complementation patterns.
Heat Transfer Coefficient and Pressure Drop of R410A During Evaporation Inside Aluminum Multiport Minichannels
Authors: Nguyen Chien , Pham Vu , Kwang-Il Choi , Jong-Taek Oh 
Published: October 2015

Micro and minichannel are progressively used in heat exchangers nowadays. The application of these heat exchanger types in refrigeration and air conditioning fields show various advantages such as high efficiency, low air side pressure, reducing refrigerant charge and the compactness size. The aim of this study is to investigate the two phase flow heat transfer coefficient and pressure drop of R410A during evaporation.
The experimental data were observed in aluminum channel with the hydraulic diameters of 1.14 and 1.16 mm, mass fluxes of 50–150 kW/m2s heat fluxes of 3–6 kW/m2, saturation temperature of 6°C and vapor quality from 0.1 to 0.9. The effect of mass flux, heat flux, and hydraulic diameter on heat transfer coefficient and pressure drop were analyzed. The database was compared with numerous well-known heat transfer coefficient and pressure drop correlations. Finally, a modify heat transfer coefficient correlation was developed that showed a good prediction against the database.
Exergetic Efficiency: A Detailed Reaction Mechanism Analysis of Hydrogen Combustion With Singlet Oxygen
Authors: Washington DeVon A. , Shapiro Howard N. 
Published: October 2015

In previous work the authors have demonstrated that when hydrogen is combusted in stoichiometric proportions at 1 atm and 1200 K, and singlet oxygen comprises 0–20% of the oxidizer, an optimal range of exergetic efficiency exists. The maximum exergetic efficiency occurs at approximately 10%. Over this range, roughly 60% of the total exergy destruction occurs prior to ignition. This is a significant result because it suggests that the exergetic efficiency of combustion might be improved at a fundamental level by chemical means, thereby inherently increasing the efficiency of fuel use for a desired energy application.
The objective of the study presented in this paper is to analyze the reaction mechanisms for combustion with varying percentages of singlet oxygen, to determine which reaction pathways most influence the observed trends in exergy destruction and exergetic efficiency. This was accomplished by performing both sensitivity and rate-of-production analyses of the hydrogen-oxygen combustion mechanism. The results of the analysis show that the presence of singlet oxygen governs the rate of production of hydroxyl and other key radicals. These key radicals directly affect the phenomenological processes associated with chemical induction and thermal induction during ignition. Therefore, the observed optimum exergetic efficiency correlates to the quantity of singlet oxygen in the inlet charge that minimizes exergy destruction by fostering chemical reactions due to radical formation to a greater extent than thermal heat release. The results of this analysis are noteworthy and provide new insight regarding how the exergetic efficiency of combustion may be optimized by introducing singlet oxygen, thereby altering the reaction pathways to enhance energy conversion in a fundamental way that could have important implications for improved fuel use.
Design of a Secondary Concentrator for a Small Particle Heat Exchange Receiver
Authors: Berchtold Olivier , Miller Fletcher 
Published: October 2015

The design of a secondary concentrator for the Small Particle Heat Exchange Receiver (SPHER) using a Monte Carlo Ray Tracing (MCRT) method is discussed in this paper. Applying basic MCRT rules, a modular solver logic for secondary concentrators is established. The logic is coded into FORTRAN subroutines to be compatible with MIRVAL, a ray trace code for heliostat fields created by Sandia National Laboratories. Based on a 3D Compound Parabolic Concentrator (3D-CPC) example the power of the simulation based on the Sandia heliostat field calculations is demonstrated.
The results of the simulations are used to calculate the solar flux distributions in the ideal 3D CPC inlet and outlet planes as well as the incident ray distribution hitting the secondary concentrator. Code modifications to account for surface irregularities and spectral reflectivity are implemented in the appropriate FORTRAN subroutine. Using the automated simulation routines first the optimal receiver tilt angle and secondly the secondary concentrator acceptance angle are determined. These parameters combined with the fixed secondary concentrator outlet radius — which is determined by the SPHER window diameter — fully constrain the 3D CPC geometry. The flux maps generated using MATLAB post processing on the derived concentrator results clearly indicate the strengths and weaknesses of the specific concentrator and heliostat field combination.
The influence of the secondary concentrator on the window incident flux distribution and window transmission, absorption and reflection properties is evaluated. Early findings using the code suggest higher yearly average power entering the receiver when compared to a non-secondary case. The reason for this effect is found in increased heliostat efficiency towards the edges of the heliostat field. At the same time the peak power hitting the window is found to increase very slightly only. This means the maximum window design specifications do not need to be adjusted dramatically to be able to accommodate the average power increase. First indications using the MCRT output in preliminary receiver simulations suggest increased receiver efficiency and a boost in receiver outlet gas temperature. The combined effect of these improvements is expected to raise overall power generation efficiency by improving the gas- / steam turbine combined cycle efficiency.
Hybrid Sensible/Thermochemical Storage of Solar Energy in Cascades of Redox-Oxide-Pair-Based Porous Ceramics
Authors: Agrafiotis Christos , Becker Andreas , Roeb Martin , Sattler Christian 
Published: October 2015

The current work is a follow-up of the idea described in previous publications, namely of combining active thermochemical redox oxide pairs like Co3O4/CoO, Mn2O3/Mn3O4 or CuO/Cu2O with porous ceramic structures in order to effectively store solar heat in air-operated Solar Tower Power Plants. In this configuration the storage concept is rendered from “purely” sensible to a “hybrid” sensible/thermochemical one and the current heat storage recuperators to integrated thermochemical reactors/heat exchangers. In addition, the construction modularity of the current state-of-the-art sensible storage systems provides for the implementation of concepts like spatial variation of redox oxide materials chemistry and solid materials porosity along the reactor/heat exchanger, to enhance the utilization of the heat transfer fluid and the storage of its enthalpy. In this perspective the idea of employing cascades of various porous structures, incorporating different redox oxide materials and distributed in a certain rational pattern in space tailored to their thermochemical characteristics and to the local temperature of the heat transfer medium has been set forth and tested.
Thermogravimetric analysis (TGA) studies described in previous works have shown that the Co3O4/CoO redox pair with a reduction onset temperature ≈ 885–905°C is capable of stoichiometric, long-term, cyclic reduction-oxidation under a variety of heatup/cooldown rates. Further such studies with the other two powder systems above, described herein, have demonstrated that the Mn3O4/Mn2O3 redox pair is characterized by a large temperature gap between reduction (≈ 950°C) and oxidation (≈ 780–690°C) temperature, whereas the CuO/Cu2O pair cannot work reproducibly and quantitatively since its redox temperature range is narrow and very close to the melting point of Cu2O. Thus, a combination of two such systems, namely Co3O4/CoO and Mn2O3/Mn3O4 has been further explored. Thermal cycling tests with these two powders together under the conditions required for complete oxidation of the less “robust” one, namely Mn3O4/Mn2O3, demonstrated in principle the proof-of-concept of the cascaded configuration, i.e. that both powders can be reduced and oxidized in complementary temperature ranges, extending thus the temperature operation window of the whole storage cascade. A suitably designed test rig where similar experiments in the form of cascades of coated honeycombs and foams can be performed has been built and further such tests are under way.
Numerical Simulation of Heat Transfer in a 3D Cavity-Receiver
Authors: Pandi Parthasarathy , Le Clercq Patrick 
Published: October 2015

The unsteady 3D fluid flow coupled to radiative, convective, and conductive heat transfers are computed within a cavity-receiver that was successfully tested experimentally. A Monte-Carlo radiation model is used in the fluid regions of the reactor with source terms outside the cavity’s window to account for the concentrated radiative power input. Darcy’s law for the viscous regime and the Forchheimer’s term for the inertial regime are used in the momentum equation to account for the pressure drop within the porous region (RPC).
Two separate energy equations for the solid and for the fluid regions of the porous domain are solved in order to capture the non-equilibrium effects in that region. Rosseland diffusion approximation is used in the solid regions of the RPC domain. The material properties and boundary conditions were taken from published experimental measurements. The simulation results are compared to the measurement data collected during the pre-heating and the ceria reduction phases, which sum up to four different radiative power inputs. Results of the comparison are very good and constitute the verification that the numerical methods, physical sub-process models and material properties are adequately selected and implemented. An analysis regarding the heat balance, the recirculating flow and, the effect of dual-scale porosity is also presented.
Piston Expanders Technology as a Way to Recover Energy From the Expansion of Highly Wet Organic Refrigerants
Authors: Fiaschi Daniele , Secchi Riccardo , Galoppi Giovanni , Tempesti Duccio , Ferrara Giovanni , Ferrari Lorenzo , Karellas Sotirios 
Published: October 2015

The design of expanders for organic fluids is gaining an increasing attention due to the large opportunities opened by the ORC as a way to recover low grade heat. The possibility of recovering at least a fraction of the energy related to throttling in inverse cycles could have interesting relapses on the market of heating (heat pumps) and refrigeration machines. The main challenge to be faced is the management of a highly wet fluid (typical quality is in the 0–0.6 range), which puts off side dynamic expanders like turbines. For this reason, piston technology is proposed and analyzed. The potential recovery from the throttling of a 20 kW target domestic heat pump cycle is determined by modeling the real expansion cycle with two different codes, a commercial one (largely widespread and very easy to use) and a purposely developed one, which is much more customizable and may include different approaches to the physical behavior of the two–phase expansion.
The results show interesting possibility of energy recovery from this generally wasted source, which opens the way to improvements of the heat pump COP from 4% to about 7%, depending on the working (i.e. seasonal) conditions. The analysis also points out the agreement in the results of two different adopted simulation tools (commercial AMESim® and self-made customizable EES®), which can be thus considered valuable in the design, analysis and optimization of the proposed expander.
Due to the biphasic nature of the working fluid, the performance of the expander is strongly influenced by the inlet conditions of the fluid from the condenser of the heat pump to the cylinders, such as throttling of the inlet/outlet valves and friction through the ducts.
On the whole, this expander technology has very interesting chances to effectively manage fluids under highly wet conditions, like those related to the throttling from upper to lower pressure of inverse cycles.
Emergency Energy Management Model for Durham Region
Authors: Sarvendran Vajran , Harvel Glenn , McKellar Jennifer , Samuel Jeffrey 
Published: October 2015

In the last 50 years, the province of Ontario has lost electrical power at various times, which has challenged Ontario’s emergency-response capabilities. In addition to the loss of electricity supply, there were concerns regarding access to diesel fuels and gasoline due to loss of electrical power to pump the fuel. However, natural gas and propane are a viable alternative energy supply in an emergency scenario.
The purpose of this project is to assess the role of natural gas in an emergency scenario and potential areas for further optimization to meet energy needs within the region of Durham, Ontario. An energy management model for the region of Durham has been developed for both electricity and natural gas. This model can be used to assess the impact of an emergency scenario on energy supply. This was achieved by researching different types of critical facilities such as hospitals, emergency services, schools, water/sewage facilities, community centers, shopping centers and gas stations and their reliance upon electricity and natural gas. Major shopping centers were included within this project as they provide communities with medical, grocery and basic needs.
Data gathered for 415 facilities was incorporated into a Visual Basic model. The data was based on floor space, population, fleet size, water consumption, fuel types and energy use behavior. Facilities were divided into categories based on sizes of less than 5,000 m2, between 5,000 m2 and 15,000 m2, and greater than 15,000 m2 for the purposes of the model. Unique facilities such as the six water treatment facilities and the ten E.M.S stations were assessed individually. The data was then used to create a model that related the available electricity and natural gas to the various types of facilities in the Durham Region.
The results show that natural gas infrastructure is already in place in the Region of Durham and many critical facilities currently use natural gas to supply heat energy. Hence, modest changes (cogeneration plants/ micro gas turbines) in the current infrastructure could be implemented to ensure emergency power is available from natural gas in a loss of electricity scenario and further improve the resiliency of the region of Durham in an emergency scenario.
Energy Efficiency and Environmental Life Cycle Assessment of Jatropha for Energy in Nigeria: A “Well-to-Wheel” Perspective
Authors: Onabanjo Tosin , Di Lorenzo Giuseppina 
Published: October 2015

There is a large imbalance between demand and supply of energy in Nigeria, with inefficient power supply being the country’s greatest economic bane. Aside energy crisis, fuel is a luxurious commodity and petroleum diesel is the predominant fuel for power generation, particularly in the industrial sector. As a result, the country suffers from forced power outages, and persistent black out while residents and industries are forced to depend on self-generated electricity. These have notably reduced industrialization and increased environmental pollution across the country. This paper proposes the use of Jatropha biodiesel as a substitute fuel to petroleum diesel. It examines the energy efficiency and environmental life cycle impact of the production and use of 1MJ of Jatropha biodiesel in a typical 126 MW (ISO rating) industrial gas turbine power plant with multi-fuel capability using life cycle assessment methodologies and principles. A net energy ratio of 2.37, 1.54, and 1.32 and fossil fuel savings of 58%, 36% and 27% were achievable under three farming system scenarios: a) base-case rain-fed, b) base-case irrigated and c) large scale farming system. Also, an environmental benefit with GHG savings of 19% was attainable under the three farming scenarios. The results demonstrate that the contribution of GHGs and effect on climate change is most significant with the end use of the fuel. It also highlights the importance of clear definition of the reference system which should be indicative of the local production system and comparative to the system under study. A favourable business and economic climate driven by demand is proposed for Independent Power Producer (IPP) to generate power for off-grid users instead of generating power for the national grid using a decentralized Jatropha biodiesel production system coupled to waste to energy technologies.
This could significantly improve the energy situation; diversify the energy generation mix and fuel supply in Nigeria, especially for small-scale businesses and the rural population.
Model Based Investigation of Liquid Water Injection Strategies for Evaporatively Cooled PEM Fuel Cells
Authors: Fly Ashley , Thring Rob H. 
Published: October 2015

Evaporative cooling through liquid water injection directly into the fuel cell flow channels removes the requirement for external humidification and liquid cooling channels within the stack. However, the amount of liquid water injected must be accurately controlled, to prevent on one hand membrane drying due to lack of water vapor and on the other hand flooding due to excessive liquid water.
In this paper a one-dimensional, non-isothermal model of an evaporatively cooled proton exchange membrane fuel cell (PEMFC) is produced. The model accounts for changes in relative humidity and temperature along the anode and cathode flow channels, water transfer through the membrane and liquid accumulation within the gas diffusion layers. The model was used to study liquid water injection strategies at both cell and localized level. The influence of current density, operating pressure and inlet humidity were investigated. Results show that provided high humidity is maintained throughout the cell, exhaust gas temperature increase from low to high current densities (0.4–1.4A/cm2) is less than 4.0°C, without the need for active temperature control. Furthermore both temperature regulation and good membrane hydration can be managed by uniform injection of liquid water throughout the cell to maintain a target cathode exhaust humidity.
Needs and Approaches for Novel Characterization of Direct Hybrid Fuel Cell/Gas Turbines
Authors: Tucker David , Haynes Comas , Geoghegan Patrick 
Published: October 2015

Solid oxide fuel cell (SOFC)/ gas turbine (GT) hybrid systems possess the capacity for unprecedented performances, such as electric efficiencies nearly twice that of conventional heat engines at variable scale power ratings inclusive of distributed generation. Additionally, these hybrids can have excellent operational flexibility with turndowns possibly as great as 85%. There are, however, developmental needs such as turbomachinery characterization and re-design. A leading example is that of greater propensity to have occurrences of stall-surge given the significantly different operating environment in contrast to conventional heat engines. Additionally, dynamic variation in power generation has to be done with significant a priori insight to avoid thermomechanical threats to cell stack and turbomachinery.
State-of-the-art approaches involving hardware-in-the-loop simulation and, ultimately, additive manufacturing are being pursued to enable such characterization and re-design considerations given variable and dynamic operability requirements. Compressor performance in hybrid systems has been characterized at the United States National Energy Technology Laboratory (NETL), inclusive of a capability of feed forward hardware-in-the-loop simulation of hybrid systems under dynamic conditions and a capability of replacing turbine and compressor components at a relatively low cost. This paper highlights some of the simulation results, and the net result is an approach that addresses hybrid system developmental needs for accommodating generation transients.
Control Oriented Discretized Cathode Control Volume Method for Improved PEM Fuel Cell Modeling
Authors: Headley Alexander J. , Chen Dongmei 
Published: October 2015

The humidity levels in PEM fuel cells has a profound effect on the performance. However, in large fuel cell stacks the relative humidity (RH) changes significantly along the length of the stack. This paper presents a control-oriented model with spatial considerations of the distribution of water vapor that can be used to properly predict and control the humidity levels in a PEM fuel cell stack.
This model predicts the dynamic response of the stack in real-time by tracking energy and mass flows in four basic CVs. To provide spatial information of the stack conditions, the cathode CV was further subdivided into 6 sub-volumes. The model was validated with experiments conducted on a 28-cell, 2kW fuel cell stack. The validation results show that the multiple CV approach can accurately predict the stack RH and voltage, and is capable of predicting localized voltage losses. This new modeling methodology shows the importance of a distributed understanding of the RH profile, and provides a tool to create control algorithms for PEM fuel cells that consider the health of all the sections of the stack.