bluuebunny/crossref_metadata_2025 huggingface dataset:
Matching Product Architecture and Supply Chain Configuration
Authors: Ülkü Sezer , Schmidt Glen M.
Published: January 2011

In this paper, we examine the suggested link between product architecture (i.e., the extent to which a product is modular vs. integral) and supply chain configuration (i.e., whether the product development is done internally by the manufacturer in an integrated supply chain or in collaboration with a supplier in a decentralized supply chain). Our model suggests that the choice of product architecture depends on firm, market, and product characteristics in addition to supply chain structure. In contrast to other studies, we find that the optimal mapping from architecture to supply chain structure is not always one‐to‐one. A decentralized supply chain may be associated with a more integral product when the technical collaboration penalty is not excessive and suppliers have significantly superior product development capabilities. Furthermore, in a decentralized supply chain, the nature of the relationship between the original equipment manufacturer and its supplier (adversarial or collaborative) plays a role in the choice of product architecture: modular architectures are more likely when the parties have adversarial relationships, while long‐term trust‐based relationships facilitate more integral product architectures.
Attachment style and symptom reporting: Examining the mediating effects of anger and social support
Authors: Kidd Tara , Sheffield David
Published: January 2011

Objective. Attachment style has been related to symptom reporting. The aim of this research was to examine whether social support and anger expression or experience mediate this relationship.

Design and methods. 141 women and 50 men from a Midlands university completed questionnaires examining attachment style, anger expression and experience, perceived social support, and symptom reporting.

Results. Significant differences were found between attachment groups on somatic, anxiety, social dysfunction, and depressive symptoms. Post hoc analysis showed differences were present between secure and preoccupied attachment styles on social dysfunction and depressed symptoms, and secure and fearful attachment styles on somatic, social dysfunction, and depressed symptoms (p <.05). ANCOVA revealed that there were no differences between attachment styles and any of the symptom scales when perceived social support, anger‐in, and trait anger were entered as covariates.

Conclusion. Results indicate that insecure attachment styles of preoccupied and fearful were associated with increased symptom reporting. Social support and anger mediated the relationship between attachment style and symptom reporting.
On conviction's collective consequences: Integrating moral conviction with the social identity model of collective action
Authors: van Zomeren Martijn , Postmes Tom , Spears Russell
Published: January 2011

This article examines whether and howmoral convictionspredict collective action to achieve social change. Because moral convictions – defined as strong and absolute stances on moral issues – tolerate no exceptions, any violation motivates individuals to actively change that situation. We propose that moral convictions have a special relationship withpoliticized identitiesand collective action because of the potentially strong normative fit between moral convictions and the action‐oriented content of politicized identities. This effectively integrates moral conviction with theSocial Identity Model of Collective Action(Van Zomeren, Postmes, & Spears, 2008), which predicts that, on the basis of a relevant social identity, group‐based anger and efficacy predict collective action. Results from two studies indeed showed that moral convictions predicted collective action intentions (Study 1–2) and collective action (Study 2) through politicized identification, group‐based anger, and group efficacy. We discuss theoretical and practical implications of our integrative model.
The age of reason: An examination of psychosocial factors involved in delinquent behaviour
Authors: Newton Nicola C. , Bussey Kay
Published: January 2011

Purpose. Delinquent behaviour among children and adolescents is escalating at a considerable rate. This has led to calls to lower the Age of Criminal Responsibility (ACR); however there is limited research on which to base such a decision. The present study addressed this omission by (1) assessing whether or not children can accurately distinguish right from wrong in relation to ‘real‐life’ transgressions and (2) investigating psychosocial factors that may constrain children from acting in accordance with their knowledge of what is right and wrong.

Methods. A total of 452 students were recruited from five schools in Sydney, Australia. Forty percent of participants were younger children recruited from Year 5 classes in primary school (mean age of 10.49), and 60% were older children from Year 8 classes in high school (mean age of 14.29). All students completed a questionnaire measuring their understanding of right and wrong, their level of moral disengagement and delinquent behaviour, and their perceived self‐efficacy relating to academic achievement, empathy, and resistance to peer pressure.

Results. The majority of children in both age groups demonstrated knowing the difference between right and wrong in relation to ‘real‐life’ transgressions. Further analyses using structural equation modelling (analysis of moment structures, AMOS) revealed that children who engaged in delinquent behaviour were unable to exercise this knowledge appropriately to regulate their behaviour. They were less able to resist peer pressure for transgressive conduct, had low levels of empathic and academic self‐efficacies, and disengaged from moral standards.

Conclusions. Implications for policy change and future research directions are proposed.
Multiple hypothalamic cell populations encoding distinct visual information
Authors: Brown Timothy M. , Wynne Jonathan , Piggins Hugh D. , Lucas Robert J.
Published: January 2011

Non‐technical summary  A retinal projection to a brain ‘clock’ in the suprachiasmatic nuclei (SCN) and various other hypothalamic regions allows light to regulate many aspects of physiology and behaviour. The exact nature of light‐evoked responses in these hypothalamic regions and the degree to which they rely upon the various classes of retinal photoreceptor is incompletely understood. Multielectrode recordings in the mouse hypothalamus reveal four classes of visually responsive neuron whose activity is altered by changes in illumination (contrast) and/or according to steady‐state light levels (irradiance). These cells appear in different locations and vary in their daily profile of electrical activity. The properties of one class suggest a direct association with regulating the SCN clock, while the others appear suited to provide more direct modulations in physiology and behaviour. Together, these findings establish a framework for understanding how light regulates such a diverse array of body systems.
Review on the Constitutive Models of Tumor Tissue for Computational Analysis
Authors: Unnikrishnan G. U. , Unnikrishnan V. U. , Reddy J. N. , Lim C. T.
Published: January 2011

A study on the constitutive models of tumor tissues is critical for the advancement of computational tools for clinical diagnosis and treatment plans. In this respect, continuum based constitutive models of tumor tissues applied in the computational analysis of tumor tissues are reviewed in this work. An introduction to the continuum based computational modeling of tumor tissue and a brief review of the applications of computational models in tumor diagnosis and treatment plans are presented in Sec. 1. The pathophysiology of tumor is given in Sec. 2. Continuum based constitutive models of tumor tissues are reviewed in Sec. 3 and in Sec. 4, conclusions and recommendations for the future development of tumor constitutive model are presented. It is the aim of the authors to provide a comprehensive study on the various constitutive models of tumors to enhance the application of biomechanical simulation of tumor tissues.
Design of an Extra-Tall Wind Resource Assessment for the Complex Terrain of the Western Appalachian Ohio Foothills
Authors: Womeldorf Carole A.
Published: January 2011

Wind resource assessments are an essential part of successful wind energy development. Currently, wind energy resource predictions for Appalachian Ohio are based on large-scale meteorological models with sparse, low-lying validation data that poorly characterize the wind given southeastern Ohio’s complex terrain. State and federal policies, today’s energy economics, and current and future wind energy and transmission technology suggest that a meso-scale assessment to identify the best of the Appalachian Ohio wind resource is worthwhile. The Wind Energy and Assessment Visualization (WEAV) is a meso-scale assessment strategy that combines three components: tall tower wind measurements, regional terrain and surface roughness GIS mapping and a computational fluid dynamics wind simulator designed for complex terrain. The wind measurement component is described here. Up to and above top current blade heights wind characteristics, including wind speed and direction at six heights, temperature at three heights, and barometric pressure and relative humidity at hub height, are being acquired every 10 minutes on the WOUB 262-meter (800-ft) communications tower for two years. This data, together with regional terrain characteristics will be top quality inputs into a wind simulator and enable modeling of the wind resource across a 2000 square mile (5,200 km2) complex terrain region. Advantages of the WEAV strategy include improved measurement of wind shear and velocities, long-term characterization of the free stream velocity field, and much broader domains of assessment. The following is a description of the motivation for and advantages of this type of study, details of the design, installation, and challenges of an extra-tall tower wind characterization, and preliminary results documenting the boom design’s tower shadow minimization.
The Performance of an Absorption Solar Cooling System Operated in Taiwan
Authors: Yang Ru , Chiu Yi-Ying
Published: January 2011

The performance of an absorption solar cooling system operated under Taiwan climate is studied via computer simulation. Solar energy is utilized as the driving energy for an absorption cooling system, and a TRNSYS computer code is employed to simulate the operation of the system. Climate data in TMY2 form for five major cities of Taiwan are input to the simulation program. Also system operating parameters of solar collector area and the size of the storage tank are varied to study there effects on the system performance. This research provides computer simulation data for the monthly solar fraction (f) as well as the seasonal solar fraction (F) for the absorption solar cooling system operated under the climate of the major cities in Taiwan. The data can provide the design needs.
Achieving Climate-Positive, Energy-Positive Homes: 60 Years of Northeast Climate Housing
Authors: Borton David , McDaniel Carl , Stoner Howard
Published: January 2011

We analyze the operating-energy histories of three homes of different ages that have approached or attained net-use of no fossil fuels and climate neutrality. The first house (H-60) with 1,200 ft2 is a conventional 1950s house that has been caulked, insulated and equipped with an airtight woodstove and a 3.3 kW photovoltaic system that reduced its annual use of fossil fuels by 86%. Its total annual energy use excluding any passive gain is ∼57 billion joules. House two (H-30) with 2,300 ft2 is a 1980s, passive-solar house with a recently added 4.0 kW photovoltaic system that reduced its annual use of fossil fuels by 71%. Its total annual energy use excluding any passive gain is ∼58 billion joules. House three (H-1) with 1,300 ft2 is a 1 year old, passive solar house with a 3.1 kW photovoltaic system and an evacuated-tube solar hot water system that uses no fossil fuels, exports annually ∼900 kWh to the grid making it energy and climate positive, and provides all operating energy from on-site sunshine. Its total annual energy use excluding any passive gain is ∼29 billion joules.
Extending Lifecycle Exergy Analysis Beyond Resource Consumption
Authors: Shah Amip , Corrigan Kiara
Published: January 2011

In this paper, we explore a reduced-order framework to predict the sustainability of a given system. The approach combines concepts from economic theory, thermodynamics, and the environmental sciences into a simple scheme that allows evaluation of system sustainability in terms of a small number of variables. The underlying hypothesis behind the work is that sustainability can be correlated to reversibility, and therefore should bear a relationship with transitions from an initial benign state. We propose evaluation along three dimensions: (i) physical; (ii) economic; and (iii) social. The measure of physical damage follows from the second law of thermodynamics, and specifically we show when and how second-law derived metrics (such as lifetime exergy consumption) can be extended to capture additional impacts. The measure of economic impact is derived by correlating physical transformations of objects with their relative economic value, specifically through use of input-output models that have been previously published in the literature. Lastly, we explore capturing social value through a proxy of indexed measures that correlate to the notion of a ‘social entropy’, which is suggested as an approximation for the deviation of society from a general state of well-being. We propose unifying all three of these approaches through a generalized framework, and thus suggest a simple but broad ‘sustainability performance’ metric. The paper concludes by discussing the challenges associated with widespread implementation, validation, and completeness of such a framework.
Investigation of an Eppler 423 Style Wind Turbine Blade
Authors: McStravick David M. , Houchens Brent C. , Garland David C. , Davis Kenneth E.
Published: January 2011

Due to the increasing demand for alternative energy sources and the reliability of wind turbines, the performance of different horizontal-axis wind turbine blade designs were investigated and compared through computational fluid dynamics (CFD) modeling and wind tunnel testing. The Eppler 423 airfoil was of particular interest. In avionics the blade has been associated with high lift and a low tendency to stall, yet little is known about its performance in wind turbines. In both physical testing and ANSYS CFX 11.0 analysis, the airfoil significantly outperformed a Nordtank 41/500 turbine blade. Wind tunnel tests were performed on 12-inch diameter ABS polymer prototypes, created with a 3D printer. To exaggerate the features of each prototype and obtain more measureable differences in turbine performance, the blades are scaled down more in the radial direction than in the profile section directions. The Eppler 423 airfoil design was tested at different blade base angles. The testing identified an optimum power production for a blade base angle of 25°. In the ANSYS CFX computer simulations, the moments on to the turbine blade due to the incoming air allowed for the power generated and the coefficient of power (Cp) to be determined and compared. The Eppler profile outperformed the Nordtank blade profile in these simulations.
Greening Tenant/Landlord Processes: Demonstrating Transformation in the Industry
Authors: Carmichael Cara , Krarti Moncef
Published: January 2011

In owner-occupied facilities, it is easy to justify the incorporation of high-performance building features because commonly recognized hard and soft benefits (cost savings, productivity gains and improved occupant health, etc.) are directly recovered by the investment entity. Developers or owners of multi-tenant office buildings and retail developments, on the other hand, encounter both perceived and real barriers that often prevent the inclusion of high-performance, climactic responsive features in new or retrofit projects. Good design, proper lease formulations, market education and intelligent operation will help overcome these barriers and allow the benefits of high-performance buildings to be realized and shared amongst various stakeholders. To demonstrate this process, strategies were analyzed for a multi-tenant building in Glenwood Springs, Colorado. The Alpine Professional Building (APB) is a three-story, 18,537 gross square foot building that was originally built in 1950 and was remodeled in 1981. The building has fifteen tenants, ranging from 143 SF of leased space to an entire floor. The HVAC systems are in need of upgrading and little has been done to the building beyond typical maintenance to keep systems in operation. This is a fairly typical scenario across the industry, which enables this analysis to be widely applicable and adaptable. Building walkthroughs, surveys, utility bill analysis and energy analysis concluded that an upgrade was needed consisting of the following package of measures: improved occupant control (thought tenant education and digital thermostats), upgrading the light fixtures in the common areas and tenant spaces, and replacing the boiler. This package has a payback period under nine years would enable the building to achieve the ENERGY STAR label and can be profitable for both tenants and the landlord. The financial analysis evaluated four different methods of financing the upgrades so that both the tenant and landlord would benefit financially from the upgrades. The financial method recommended is the ‘CAM Adjustment method’ in which the landlord would provide the initial capital for the upgrades and recover those costs (plus interest) through adjustments to the Common Area Maintenance (CAM) fees. This method would have minimal tenant disruption and enable the landlord to bridge costs and savings across tenants during turnover. This paper also compares the four financing mechanisms and demonstrates their industry applicability through commonly applied energy conservation measures.
Effect of Multiple Injection Strategy on Atomization and Emission Reduction Characteristics in a Diesel-Ethanol Fueled Engine
Authors: Park Su Han , Youn In Mo , Park Sung Wook , Lee Chang Sik
Published: January 2011

The aim of this work is to investigate the effect of the multiple injections on the overall spray and the exhaust emissions characteristics in a common rail four cylinder diesel engine operated using diesel-ethanol blended fuels. In order to prevent the phase separation in blended fuels, biodiesel fuel that based on palm oil added to the blended fuels. The reduction problem of cetane number in blended fuels was supplemented by the addition of biodiesel fuel. The spray characteristics were analyzed through the spray images which obtained by the high speed camera. In addition, the combustion and exhaust emissions characteristics were measured and analyzed by using a four cylinder diesel engine with common rail injection system. It revealed that the increase of the injection interval induces the slow development rate of the second spray in the multiple injection modes. The spray cone angle of the single injection mode is wider than that of the multiple injection modes. The advance of the first injection timing caused the reduction of the second injection quantity, and the relaxation of the combustion pressure rise rate. NOx emission shows a reduction trend by the increased ethanol blending ratio, while it shows an increasing pattern by the advance of the first injection timing at the fixed second injection. In HC and CO emissions, the short injection interval between the first and the second injections is better than long injection interval.
An Advanced Power-Generation System With CO2 Recovery Integrating Dimethyl Ether (DME) Fueled Chemical-Looping Combustion
Authors: Han Tao , Hong Hui , Jin Hongguang , Zhang Chuanqiang
Published: January 2011

Dimethyl ether (DME) is a promising alternative fuel, but direct combustion of DME will result in extra energy penalty for CO2 separation. In this paper, an advanced power-generation system with CO2 recovery integrating DME-fueled chemical-looping combustion is proposed. In the reduction reactor, DME is oxidized by Fe2O3 into CO2 and H2O, and Fe2O3 is reduced into FeO simultaneously. Since the endothermic reduction of Fe2O3 with DME requires relatively low-grade thermal energy around 180°C, waste heat is used to provide the reaction heat. FeO is oxidized into Fe2O3 by air in the oxidation reactor, producing high-temperature flue gas to generate electricity through a thermal cycle. The gas production from the fuel reactor only consists of CO2 and H2O, so CO2 can be easily separated through condensing with no extra energy penalty. As a result, the thermal efficiency could be expected to be 58.6% at a turbine inlet temperature of 1288°C. Additionally, experiments on DME-fueled Chemical-looping combustion are carried out to verify the feasibility of the core process. This proposed system may provide a new approach for high efficient use of DME in the industrial fields, and offer a possibility of chemical-looping combustion with inherent CO2 capture for the alternative fuel.
Validation of a Simulation Model for a Combined Otto and Stirling Cycle Power Plant
Authors: McGovern Jim , Cullen Barry , Feidt Michel , Petrescu Stoian
Published: January 2011

A project has been underway at the Dublin Institute of Technology (DIT) to investigate the feasibility of a combined Otto and Stirling cycle power plant in which a Stirling cycle engine would serve as a bottoming cycle for a stationary Otto cycle engine. This type of combined cycle plant is considered to have good potential for industrial use. This paper describes work by DIT and collaborators to validate a computer simulation model of the combined cycle plant. In investigating the feasibility of the type of combined cycle that is proposed there are a range of practical realities to be faced and addressed. Reliable performance data for the component engines are required over a wide range of operating conditions, but there are practical difficulties in accessing such data. A simulation model is required that is sufficiently detailed to represent all important performance aspects and that is capable of being validated. Thermodynamicists currently employ a diverse range of modeling, analysis and optimization techniques for the component engines and the combined cycle. These techniques include traditional component and process simulation, exergy analysis, entropy generation minimization, exergoeconomics, finite time thermodynamics and finite dimensional optimization thermodynamics methodology (FDOT). In the context outlined, the purpose of the present paper is to come up with a practical validation of a practical computer simulation model of the proposed combined Otto and Stirling Cycle Power Plant.
Strategies for Performance Enhancement of Tesla Turbines for Combined Heat and Power Applications
Authors: Romanin Vince , Carey Van P. , Norwood Zack
Published: January 2011

A small, efficient, and robust turbine is essential to the development of a small-scale (∼10 kWe) Combined Heat and Power (CHP) Rankine cycle system. While the Tesla turbine design offers a versatile solution with a low manufacturing and maintenance cost, its successful use in systems of this type hinges on development of a design that also offers high energy conversion efficiency. The investigation summarized here explored the parametric trends in Tesla turbine efficiency using model analysis of the turbine performance in tandem with experimental testing of a small scale Tesla turbine. The experimental data were used to evaluate the accuracy of trends predicted by the model analysis. Results of this evaluation show agreement between calculated and experiential efficiency. To further test the model, several non-dimensional parameters that arise from the model analysis were used to predict design modifications to the existing turbine that would improve turbine performance. Several of these modifications were fabricated and tested. Results show that the model is able to accurately predict efficiency variations that result from changes in turbine design. The model is then used to project new turbine designs that will maximize the efficiency of the turbine and recommendations are made for further improving Tesla turbine efficiency. Lastly, improved Tesla turbine designs are discussed in terms of their appropriateness for use in CHP Rankine cycle systems.
Study of High Temperature Nanofluids Using Carbon Nanotubes (CNT) for Solar Thermal Storage Applications
Authors: Jo Byeongnam , Banerjee Debjyoti
Published: January 2011

The aim of this study is to investigate enhancement of thermal properties of various high temperature nanofluids using Carbon Nanotubes (CNT) for solar thermal energy storage applications. The specific heat of liquid carbonate salt eutectics that are doped with CNT was measured using Differential Scanning Calorimeter (DSC). A eutectic mixture of lithium carbonate (Li2CO3) and potassium carbonate (K2CO3) at a molar ratio of 62:38 is used as the base fluid (solvent). A surfactant (Sodium Dodecyl Sulfate or “SDS”) was used to obtain well-dispersed suspension of CNT in distilled water. This CNT suspension was added to an aqueous solution of two alkali carbonate salts in the form of a eutectic mixture. The resulting solution was evaporated on a hot-plate to obtain a dry mixture of CNT (at 1% concentration by weight) in the carbonate eutectic. The samples were synthesized for by evaporating at four different hotplate temperatures of 100 °C, 120 °C, 140 °C, and 160 °C. The results showed that specific heat capacities of carbonate eutectic-CNT nanofluids were linearly increased as the hotplate temperature was increased. At higher temperatures the water was evaporated faster — leading to less agglomeration of the nanoparticles in the nanofluids and thus resulting in higher values of the measured specific heat of the nanofluids.
Effect of Camera-Like Aperture in Quest for Maintaining Quasi-Constant Radiation Inside a Solar Reactor
Authors: Ozalp Nesrin , Toyama Anthony , Krishna D. Jaya , Rowshan Reza , Al-Hamidi Yasser
Published: January 2011

Solar reactors can convert intermittent solar radiation into storable chemical energy in the form of fuels that are transportable. In order to use solar energy as a source of high temperature process heat in a solar reactor, incident radiation needs to be concentrated over a small surface area, the inlet of which is called the aperture. The image of the incoming solar radiation over the aperture can be approximated by a Gaussian distribution where the solar radiation inside the reactor varies by the peak value and aperture size. Due to the transient nature of solar energy, there is a critical need for proper control to maximize system efficiency under field conditions. This paper provides numerically proven advantages of having a camera-like variable aperture, one which is sensitive to natural variations in solar flux, and having the ability to shrink or enlarge accordingly in order to maintain quasi-constant radiation inside the reactor. Our numerical results from optical, thermodynamic, and flow dynamic simulations led us to develop a computational two dimensional heat transfer distribution model inside the reactor in order to validate our optical results. The simulation results show that a changing aperture diameter with respect to a changing incoming solar flux density facilitates keeping quasi-constant and homogenous temperature distributions inside the reactor. Since the temperature has a major impact on reactant to product conversion efficiency, by keeping the temperature constant, process efficiency is kept high. By maintaining the internal temperature despite variable operating conditions the system can maintain peak performance through a wider insolation range than fixed aperture systems.
Systems Integration for Cost Effective Carbon Neutral Buildings: A Masdar Headquarters Case Study
Authors: Boyer Jeffrey L. , Jalayerian Mehdi , Silverstein Andrew , Araji Mohamad T.
Published: January 2011

Essential to the development of a low carbon economy will be the advancement of building product and process to reduce the capital and whole lifecycle cost of low, zero and net-positive energy buildings to allow these structures to be realized at a greater rate. On the whole, the built environment is responsible for one of the largest fractions of global energy consumption and thus anthropomorphic climate change, a result of the greenhouse gas emissions from power generation. When one also considers the energy required to design, fabricate, transport and construct the materials necessary to bring new building stock online, keeping pace with the rapid trend towards urbanization, the importance of the built environment in the energy sustainability equation is clearly evident. Yet, while technologically feasible, the realization of carbon neutral buildings is encumbered by the perception of increased annualized costs for operation and a greater upfront investment. This paper will review the design case of the Masdar International Headquarters, the flagship building of the net-zero carbon emission Masdar city currently being developed within the Abu Dhabi Emirates. Specifically, how an integrated approach enabled by computer simulation early within the design process allowed for improvements in economy and efficiency, setting a model for future high performance buildings. The five-story, 89,040-square-meter office building will incorporate eleven sculpted glass environmental towers to promote natural ventilation and introduce daylight to the interior of the building. These towers will also serve as the structural support for one of the world’s largest building integrated photovoltaic arrays, sized to supply 103% of the building’s total annual energy requirements while protecting the building and roof garden from intense heat and solar gains. Moreover, by integration into a separate structural trellis system, clean energy can potentially be generated to offset construction requirements while dually shading workers below during the heat of the day. This, along with other key sustainability design strategies such as a solar powered central district cooling system, thermoactive foundation piling, underfloor air distribution, desiccant dehumidification, a nanotechnology enabled building envelope and smart grid enabled facilities management infrastructure will allow the Masdar Headquarters to reach carbon neutrality within a decade, allowing for the remaining century of its operation to serve as a platform for clean energy generation.
Life Cycle Assessment of a Model Parabolic Trough Concentrating Solar Power Plant With Thermal Energy Storage
Authors: Burkhardt John J. , Heath Garvin , Turchi Craig
Published: January 2011

This study evaluates the environmental impacts of a hypothetical 103 megawatt, parabolic trough, wet-cooled concentrating solar power (CSP) plant in the U.S. Southwest with 6.3 hours of thermal energy storage by means of a hybrid life cycle assessment. Life cycle greenhouse gas emissions, cumulative energy demand, and water consumption associated with the manufacture, construction, operation, dismantling, and disposal of the power plant are evaluated and disaggregated by major systems and components. The reference CSP plant emits 26 g CO2eq per kWh of electrical output across its life cycle, cumulatively demands 0.43 MJeq/kWh of energy, and consumes 4.7 L/kWh of water. The majority of water is consumed by the power block for evaporative cooling. Sensitivity analyses are performed on several key assumptions and design elements: the configuration of the thermal energy storage system (i.e., thermocline), the heat transfer fluid, the nitrate salts, the cooling system type (i.e., dry-cooled) and the energy required for construction and end-of-life dismantling. Our base case results are robust to alternative assumptions regarding the heat transfer fluid and energy required for construction and dismantling; however, the total life cycle impacts are strongly influenced by the type of cooling system and nitrate salts employed.
Research on Assessment Method of Green Buildings in China
Authors: Wei Bing , Zhang Bin , Luo Wen
Published: January 2011

Presently the sustainable development stratagem has made the green buildings to be a trend of building industry in China, and the assessment to the green buildings is becoming more and more important in developing the green buildings. In this paper the meaning of the green building assessment is explained, several main domestic and foreign green building assessment systems are analyzed and compared, and the common ground and limitations of these assessment methods are presented. Then a novel assessment index system which is more comprehensive, scientific and suitable for green buildings in China is developed by using the life cycle assessment method. This system contains six categories including land saving and outdoor environment, energy saving and utilization, material saving and utilization, water saving and utilization, indoor environment quality and economy. According to the decision-making stage, design stage, construction stage, operation and maintenance stage, each category is divided into more concrete indexes. At last the established assessment system is used to evaluate a typical building in Xi’an, China. The final novel assessment index system is of theoretical and practical significance for the assessment and development of green buildings in China.
A Simple Method to Estimate Energy Savings for Structural Insulated Panels Applied to Single Family Homes
Authors: McCullom Ishimine , Krarti Moncef
Published: January 2011

Structural Insulated Panels (SIPs) have the potential to provide well insulated and air tight homes and thus better energy performance than the conventional wood-frame construction. Currently a SIP home is slightly more expensive to build than a conventional wood-frame home. This paper summarizes the results of a detailed study to compare the energy consumption of both SIP and wood-frame houses in representative climate zones across the United States. A simplified method to estimate the potential energy savings associated with SIP homes relative to an equivalent wood-frame home is developed and presented. As an application of the simplified method, a life cycle cost analysis was conducted to assess the cost effectiveness of building SIP homes throughout the US.
Economic Optimization of Shell and Tube Heat Exchanger Based on Constructal Theory
Authors: Amidpour Majid , Azad Abazar Vahdat
Published: January 2011

In this paper, the new approach of Constructal theory has been employed to design shell and tube heat exchangers. Constructal theory is a new method for optimal design in engineering applications. The purpose of this paper is optimization of shell and tube heat exchangers by reduction of total cost of the exchanger using the constructal theory. The total cost of the heat exchanger is the sum of operational costs and capital costs. The overall heat transfer coefficient of the shell and tube heat exchanger is increased by the use of constructal theory. Therefore, the capital cost required for making the heat transfer surface is reduced. Moreover, the operational energy costs involving pumping in order to overcome frictional pressure loss are minimized in this method. Genetic algorithm is used to optimize the objective function which is a mathematical model for the cost of the shell and tube heat exchanger and is based on constructal theory. The results of this research represent more than 50% reduction in costs of the heat exchanger.
Reducing Energy Consumption of Ground Vehicles by Active Flow Control
Authors: Bellman Miles , Agarwal Ramesh , Naber Jonathan , Chusak Lee
Published: January 2011

In U.S, the ground vehicles consume about 77% of all (domestic and imported) petroleum; 34% is consumed by automobiles, 25% by light trucks and 18% by large heavy duty trucks and trailers. It has been estimated that 1% increase in fuel economy can save 245 million gallons of fuel/year. Additionally, the fuel consumption by ground vehicles accounts for over 30% of CO2 and other greenhouse gas (GHG) emissions. Moreover, most of the usable energy from the engine goes into overcoming the aerodynamic drag (53%) and rolling resistance (32%); only 9% is required for auxiliary equipment and 6% is used by the drive-train. 15% reduction in aerodynamic drag at highway speed of 55mph can result in about 5–7% in fuel saving. The goal of this paper is to demonstrate by numerical simulations that the active flow control (AFC) technology can be easily deployed /retrofitted to reduce the aerodynamic drag of ground vehicles by 15–20% at highway speed. For AFC, we employ a few oscillatory jet actuators (also known as synthetic jet actuators) at the rear face of the ground vehicle. These devices are easy to incorporate into the existing vehicles with very modest cost. The cost may come down significantly for a large volume — in hundreds of millions, especially for ground vehicles. Numerical simulations are performed using the Unsteady Reynolds-Averaged Navier-Stokes (URANS) equations on solution adaptive structured grids in conjunction with a two-equation realizable k-ε turbulence model. The commercially available grid generator “GAMBIT” and the CFD solver “FLUENT” are employed in the simulations. Three generic ground vehicle configurations are considered in the simulations; the experimental data has been available for these configurations without and with AFC. The numerical simulations are in good agreement with the experimental data. These studies clearly demonstrate that the AFC techniques can be effectively employed to achieve significant reduction (10–15%) in aerodynamic drag of ground vehicles thereby reducing the fuel consumption by 5–7%.
Conceptual and Basic Design of a Stirling Engine Prototype for Electrical Power Generation by Solar Means
Authors: Roldan Constantino , Pieretti Pedro , Solorzano Luis Rojas
Published: January 2011

The research consisted in a conceptual and basic design of a prototype Stirling engine with the purpose of taking advantage of the solar radiation to produce electric energy. The work began with a bibliography review covering aspects as history, basic functioning, design configurations, applications and analysis methods, just to continue with the conceptual design, where the prototype specifications are determined. Finally, a basic dimensioning of the important components as heat exchangers (heater, cooler, and regenerator), piston, displacer and solar collector was elaborated. The principal conclusions were that the different analysis methods had dissimilitude between the results, in this sense, a construction of the prototype is necessary for the understanding of the complex phenomena occurring inside the engine.
Application of Regional Bio-Refining to Increase the Sustainability and Energy Self-Sufficiency of Rural and Agricultural Communities
Authors: Gallaspy David T. , Sears Rodney E.
Published: January 2011

The economics and potential offsets of imported energy are analyzed. Benefits to the carbon footprint of the region are estimated. A commercial structure for the operation of such a co-operative bio-refinery is proposed. Rural and agricultural regions typically have ample production of biomass in various forms, including wood from forestry, agricultural wastes and range grasses. Certain regions also have renewable energy resources such as wind power, solar insolation and hydraulic power. Rural regions are typically seen to have a potential for renewable energy that greatly exceeds energy consumption due to human activity in the region. However, energy consumption in such areas is highly biased toward non-renewable sources, just as in more urbanized regions. This is due to the standardization of virtually all manufactured energy conversion equipment to use available processed energy sources such as electricity and natural gas and refined fuels such as diesel and gasoline. In addition, agricultural activities are highly dependent on energy-intensive petrochemicals such as fertilizers, pesticides, and herbicides. Energy sustainability and self-sufficiency can therefore be increased by conversion of local renewable resources into appropriate form values for existing energy conversion equipment. Solar power, wind power and hydropower are fully commercial, although more economic in some regions than in others. The production of electricity from biomass fuels via conventional steam cycles is well established, if challenging from an economic standpoint. However, conversion of biomass and other renewable resources into fuels that can be used in standard equipment, and chemicals and fertilizers for local agricultural production is both technically and economically challenging. The authors evaluate the potential for a typical rural region to offset imports of conventional non-renewable energy such as electricity, engine fuels, and fertilizers via the establishment of a regional bio-refinery financed and operated as a local co-operative. The renewable resources of the typical rural region are assumed to facilitate the analysis. The appropriate technologies, scope, product slate, production rates, capital costs and operating costs for the bio-refinery are defined.
Multi-Axial Fatigue Life Assessment of Wind Turbine Structural Components
Authors: Wei Zhigang , Forte Thomas P.
Published: January 2011

Modern wind turbines, which are usually made of composite materials, are fatigue critical structures that are subjected to variable multi-axial fatigue loading. Therefore, they should be designed as safely as necessary to withstand the fatigue loads over the designed life time. Path-Dependent Maximum Range (PDMR) is a multi-axial fatigue life assessment tool developed by Battelle researchers. PDMR has been successfully applied to fatigue analysis of isotropic structures under general variable amplitude, multi-axial fatigue loading histories. The effectiveness of the PDMR method has been validated by its ability to correlate a large amount of fatigue data available in the literature. For uniaxial loading data, PDMR gives exactly the same results as ASTM standard Rainflow cycle counting method. In this paper, the PDMR method is extended to composite materials, such as glass fiber reinforced plastics (GFRP) and carbon fiber reinforced plastics (CFRP). The proposed multi-axial fatigue damage model effectively correlates fatigue lives of unidirectional composites for various off-axis ply angles under cyclic tensile loading. With this extended capability, the PDMR can now be used to assess the multi-axial fatigue life of composite structures used in wind energy industry.
Catalytic Hydrothermal Conversion of Glucose to Light Petroleum Alkanes
Authors: Yin Sudong , Pan Yanglin , Tan Zhongchao
Published: January 2011

The production of carbon-neutral liquid fuels from renewable biomass has attracted worldwide interest in an age of depletion of fossil fuel reserves and pollutions caused by utilization of fossil petroleum. Currently, commercial bio-oil production technologies include bio-ethanol, bio-diesel and pyrolysis bio-oil. But, these bio-oils mainly consist of alcohols and aromatic chemicals rather than alkanes of the main components of gasoline and diesel. Direct utilization of these bio-oils can corrode car engines as well as emitting large unburned hydrocarbons particles through automotive combustion system. Therefore, in this study, catalytic hydrothermal conversion (CHTC) of glucose to alkanes in a single batch reactor was investigated with respect to effects of conversion parameters such as initial pressure of process gas H2, pH level of aqueous solution and catalysts on alkane yields and compositions. Results showed that the highest alkane yield of 21.6% (based on the mol of the input glucose) was obtained at 265 °C, with 300 psi of H2 process gas, 0.5 g catalyst of 1w%. Pt/Al2O3 and a residence time of 15 h. The alkane yield was significantly influenced by the initial pressure of H2, which increased with increasing H2 pressure. On the other hand, the alkane yields first increased and then decreased with pH levels. Also, more alkanes were produced by Pt/Al2O3 than Pd/Al2O3. Regarding alkane compositions, high initial pressure of H2 favored the production of relatively heavy C3–4 alkanes. With 300 psi of initial H2, C3H8 and C4H10 accounted for 75% of the total produced alkanes. All of the experimental data in this study lead to one conclusion that petroleum alkanes can be directly produced from glucose.
Solar Furnace Heliostat Closed-Loop Control System
Authors: Glenn Kyle
Published: January 2011

A 4.2 kW solar furnace heliostat was interfaced with a closed-loop control system to manipulate the azimuth and elevation rotational degrees of freedom to continuously align a solar concentrator with the sun. A QP50-6SD2 quadrant photodiode laser beam positioning device, developed by Pacific Silicon and Sensor, was modified to sense the orientation of the sun. The quadrant photodiode was mounted inside a dark box with a pinhole aperture and mounted so that when the heliostat reflects light along the desired axis, the quadrant photodiode relays balanced error signals. These error signals were interpreted with a Basic Stamp 2p40 microcontroller developed by Parallax Inc. LM741 operational amplifiers and ADC0831 analog to digital converters were used for signal conditioning. The 2p40 microcontroller interprets and checks the error signals every 500ms and uses a ULN2803 Darlington Transistor array to activate the heliostat drive motor’s solid-state relays to maintain solar alignment. The closed-loop heliostat control system can track with 1.6 degrees of accuracy. This is closer than the original prediction of 3 degrees. The control system requires user-inputs for initial alignment. Alignment can initiate with the heliostat out of alignment by at least 6 degrees. The versatility of the 2p40 allows subroutines to be programmed in that can handle hysteresis in the slewing of the heliostat, continue tracking as the heliostat begins to wobble from wind gusts, or continue tracking during intermittent shadowing from clouds.
Performance of Add-On Heat Pump Water Heater (HPWH) Systems and Their Impacts on Electric Utility Loads
Authors: Sharaf-Eldeen Yahya I. , Muccio Craig V. , Gay Eric
Published: January 2011

This work involves measurements, analyses, and evaluations of the performance of add-on, Heat Pump Water Heater (HPWH) systems in residential and small commercial applications. Two air-source Heat Pump (HP) systems rated at 7,000- and 12,000-BTU (2.051- and 3.517-kWh), were utilized in this work. The two HPs were retrofitted to two 50-gallon (189.3 liters) electric-resistance storage water-heaters with their electric heating elements removed. A third, standard electric water-heater (EWH), was used for comparison. The testing set-up was fully instrumented for measurements of pertinent parameters, including inlet and outlet water temperatures, inlet and outlet air temperatures of the HPs, temperature and humidity of the air in the surrounding space, volume of water draws out of the storage heater tanks, as well as electric energy consumptions of the systems. Several performance measures were used in this work, including the Coefficient of Performance (COP), which is a measure of the instantaneous energy output in comparison with the energy input; Energy Factor (EF), which is an average measure of the COP taken over extended periods of time; and the First Hour Rating (FHR), which is a measure of the maximum volume of hot water that a storage type water-heater can supply to a residence within an hour. The results obtained clearly indicate that, HPWH systems are much more efficient as compared to standard EWHs. While the average value of the EF for a standard EWH is close to 1.0, the HPWH systems yield EFs averaging more than 2.00, resulting in annual energy savings averaging more than 50%. The results also showed that, HPWH systems are effective at reducing utility peak demand-loads, in addition to providing substantial cost savings to consumers.