bluuebunny/crossref_metadata_2025 huggingface dataset:
Population genomic analyses of early‐phase Atlantic Salmon (Salmo salar) domestication/captive breeding
Authors: Mäkinen Hannu , Vasemägi Anti , McGinnity Philip , Cross Tom F. , Primmer Craig R.
Published: October 2014

Domestication can have adverse genetic consequences, which may reduce the fitness of individuals once released back into the wild. Many wild Atlantic salmon (Salmo salar L.) populations are threatened by anthropogenic influences, and they are supplemented with captively bred fish. The Atlantic salmon is also widely used in selective breeding programs to increase the mean trait values for desired phenotypic traits. We analyzed a genomewide set of SNPs in three domesticated Atlantic salmon strains and their wild conspecifics to identify loci underlying domestication. The genetic differentiation between domesticated strains and wild populations was low (FST < 0.03), and domesticated strains harbored similar levels of genetic diversity compared to their wild conspecifics. Only a few loci showed footprints of selection, and these loci were located in different linkage groups among the different wild population/hatchery strain comparisons. Simulated scenarios indicated that differentiation in quantitative trait loci exceeded that in neutral markers during the early phases of divergence only when the difference in the phenotypic optimum between populations was large. This study indicates that detecting selection using standard approaches in the early phases of domestication might be challenging unless selection is strong and the traits under selection show simple inheritance patterns.
DCT protects human melanocytic cells from UVR and ROS damage and increases cell viability
Authors: Ainger Stephen A. , Yong Xuan L. , Wong Shu S. , Skalamera Dubravka , Gabrielli Brian , Leonard J. Helen , Sturm Richard A.
Published: October 2014

Dopachrome tautomerase (DCT) is involved in the formation of the photoprotective skin pigment eumelanin and has also been shown to have a role in response to apoptotic stimuli and oxidative stress. The effect of DCT on UVR DNA damage responses and survival pathways in human melanocytic cells was examined by knockdown experiments using melanoma cells, neonatal foreskin melanoblasts (MB) in monoculture and in co‐culture with human keratinocytes. MB cell strains genotyped as either MC1R WT or MC1R RHC homozygotes, which are known to be deficient in DCT, were transduced with lentivirus vectors for either DCT knockdown or overexpression. We found melanoma cell survival was reduced by DCT depletion and by UVR over time. UVR‐induced p53 and pp53‐Ser15 levels were reduced with DCT depletion. Knockdown of DCT in MC1R WT and MC1R RHC MB cells reduced their survival after UVR exposure, whereas increased DCT protein levels enhanced survival. DCT depletion reduced p53 and pp53‐Ser15 levels in WM266‐4 melanoma and MC1R WT MB cells, while MC1R RHC MB cells displayed variable levels. Both MC1R WT and RHC genotypes of MB cells were responsive to UVR at 3 h with increases in both p53 and pp53‐Ser15 proteins. MC1R WT MB cell strains in coculture with keratinocytes have an increased cell survival after UVR exposure when compared to those in monoculture, a protective effect which appears to be conferred by the keratinocytes.
Nineteenth century narratives reveal historic catch rates for Australian snapper (Pagrus auratus)
Authors: Thurstan Ruth H , Campbell Alexander B , Pandolfi John M
Published: October 2014

Snapper (Pagrus auratus) is widely distributed throughout subtropical and temperate southern oceans and forms a significant recreational and commercial fishery in Queensland, Australia. Using data from government reports, media sources, popular publications and a government fisheries survey carried out in 1910, we compiled information on individual snapper fishing trips that took place prior to the commencement of fisherywide organized data collection, from 1871 to 1939. In addition to extracting all available quantitative data, we translated qualitative information into bounded estimates and used multiple imputation to handle missing values, forming 287 records for which catch rate (snapper fisher−1 h−1) could be derived. Uncertainty was handled through a parametric maximum likelihood framework (a transformed trivariate Gaussian), which facilitated statistical comparisons between data sources. No statistically significant differences in catch rates were found among media sources and the government fisheries survey. Catch rates remained stable throughout the time series, averaging 3.75 snapper fisher−1 h−1 (95% confidence interval, 3.42–4.09) as the fishery expanded into new grounds. In comparison, a contemporary (1993–2002) south‐east Queensland charter fishery produced an average catch rate of 0.4 snapper fisher−1 h−1 (95% confidence interval, 0.31–0.58). These data illustrate the productivity of a fishery during its earliest years of development and represent the earliest catch rate data globally for this species. By adopting a formalized approach to address issues common to many historical records – missing data, a lack of quantitative information and reporting bias – our analysis demonstrates the potential for historical narratives to contribute to contemporary fisheries management.
The European Commission and the European Defence Agency: A Case of Rivalry?
Authors: Fiott Daniel
Published: October 2014

This article analyzes relations between the European Commission and the European Defence Agency (EDA) as they relate to European defence‐industrial co‐operation. To undertake the analysis, the article departs from a strictly intergovernmental‐supranational study of institutional relations by building upon the concept of ‘mandate overlap’. Additionally, the focus is on the constitutive policy approach of each institution. The EDA's approach is characterized as ad hoc and project‐based in nature, and the European Commission's approach is structural and market‐based. Once the two approaches are delineated, the article then investigates whether either of the bodies has deviated from their respective mandates over a period beginning in 1996 and ending in 2013. On this basis, the conclusion is that there is evidence of rivalry between the two bodies, especially when European Union Member States decide to use either entity to secure their interests.
Track analysis, simulation, and field survey of the 2013 Typhoon Haiyan storm surge
Authors: Takagi H. , Esteban M. , Shibayama T. , Mikami T. , Matsumaru R. , De Leon M. , Thao N.D. , Oyama T. , Nakamura R.
Published: October 2014

The authors have examined the characteristics of Typhoon Haiyan (Yolanda), which made landfall on the coast of the Philippines on November 2013, generating a substantial storm surge. In order to better understand the storm surge phenomenon, its nature and severity were analysed by means of a numerical simulation and a field survey. Unlike most other tropical cyclones that weaken before they hit land, Haiyan struck Leyte Island at near peak strength, with maximum sustained wind speeds of 160 knots, the strongest in the recorded history of the Western North Pacific. Haiyan approached very quickly with a forward speed of 41 km/h towards Leyte, which was also the fastest among typhoons with similar intensities. As a result of these extreme gusts and the exceptionally low central pressure of the typhoon (895 hPa), Haiyan caused the largest storm surge in the recorded history of the Philippines. Numerical simulations show that the maximum storm surges occurred in Leyte Island and Samar Island. A storm surge field survey conducted by the authors corroborated this, with maximum inundation height of 7 m recorded in Tacloban, located at the northern end of Leyte Gulf. The simulation results also corroborate the fact that water levels at some locations first lowered and then rapidly began to increase after an hour.
Building a Measurement Model for Market Visioning Competence and Its Proposed Antecedents: Organizational Encouragement of Divergent Thinking, Divergent Thinking Attitudes, and Ideational Behavior
Authors: Reid Susan E. , de Brentani Ulrike
Published: October 2014

The overall question that this research seeks to answer is the following: Are there individual and/or organizational resources related to “divergent thinking” that enhance or inhibit the firm's market visioning competence in the case of radical innovation? In order to answer this question, in this paper, the key focus is on the realm of potential divergent thinking‐related resources that the firm may possess and access to aid in the creation and development of an effective market visioning competence. In particular, individual‐level factors related to divergent thinking capabilities and, at the organizational level, encouragement of such capabilities, are investigated. Specifically, we propose that two organizational‐level factors related to organizational encouragement of divergent thinking (“encouraging ideas” and “encouraging diversity”), two individual‐level divergent thinking attitudes factors (“openness” and “ability to move from divergent thinking to convergent thinking efficiently and effectively”), one individual‐level ideational behavior factor (“ability to generate new ideas”), and a further individual cognitive factor (“need for cognition”) have direct impacts on market visioning competence. Scales are then developed and tested for measuring these potential antecedents, and they are included in a measurement model with market visioning competence to enable further research.
Characterization and comparison of toxin‐producing isolates of Dinophysis acuminata from New England and Canada
Authors: Tong Mengmeng , Smith Juliette L. , Richlen Mindy , Steidinger Karen A. , Kulis David M. , Fux Elie , Anderson Donald M.
Published: October 2014

Following the identification of the first toxic isolate of Dinophysis acuminata from the northwestern Atlantic, we conducted detailed investigations into the morphology, phylogeny, physiology, and toxigenicity of three isolates from three sites within the northeastern U.S./Canada region: Eel Pond and Martha's Vineyard, Massachusetts, and the Bay of Fundy. Another isolate, collected from the Gulf of Mexico, was grown under the same light, temperature, and prey conditions for comparison. Despite observed phenotypic heterogeneity, morphometrics and molecular evidence classified the three northwestern Atlantic isolates as D. acuminata Claparède & Lachmann, whereas the isolate from the Gulf of Mexico was morphologically identified as D. cf. ovum. Physiological and toxin analyses supported these classifications, with the three northwestern Atlantic isolates being more similar to each other with respect to growth rate, toxin profile, and diarrhetic shellfish poisoning (DSP) toxin content (okadaic acid + dinophysistoxin 1/cell) than they were to the isolate from the Gulf of Mexico, which had toxin profiles similar to those published for D. cf. ovum F. Schütt. The DSP toxin content, 0.01–1.8 pg okadaic acid (OA) + dinophysistoxin (DTX1) per cell, of the three northwestern Atlantic isolates was low relative to other D. acuminata strains from elsewhere in the world, consistent with the relative scarcity of shellfish harvesting closures due to DSP toxins in the northeastern U.S. and Canada. If this pattern is repeated with the analyses of more geographically and temporally dispersed isolates from the region, it would appear that the risk of significant DSP toxin outbreaks in the northwestern Atlantic is low to moderate. Finally, the morphological, physiological, and toxicological variability within D. acuminata may reflect spatial (and/or temporal) population structure, and suggests that sub‐specific resolution may be helpful in characterizing bloom dynamics and predicting toxicity.
Of linkers and autochaperones: an unambiguous nomenclature to identify common and uncommon themes for autotransporter secretion
Authors: Drobnak Igor , Braselmann Esther , Chaney Julie L. , Leyton Denisse L. , Bernstein Harris D. , Lithgow Trevor , Luirink Joen , Nataro James P. , Clark Patricia L.
Published: October 2014

Autotransporter (AT) proteins provide a diverse array of important virulence functions to Gram‐negative bacterial pathogens, and have also been adapted for protein surface display applications. The ‘autotransporter’ moniker refers to early models that depicted these proteins facilitating their own translocation across the bacterial outer membrane. Although translocation is less autonomous than originally proposed, AT protein segments upstream of the C‐terminal transmembrane β‐barrel have nevertheless consistently been found to contribute to efficient translocation and/or folding of the N‐terminal virulence region (the ‘passenger’). However, defining the precise secretion functions of these AT regions has been complicated by the use of multiple overlapping and ambiguous terms to define AT sequence, structural, and functional features, including ‘autochaperone’, ‘linker’ and ‘junction’. Moreover, the precise definitions and boundaries of these features vary among ATs and even among research groups, leading to an overall murky picture of the contributions of specific features to translocation. Here we propose a unified, unambiguous nomenclature for AT structural, functional and conserved sequence features, based on explicit criteria. Applied to 16 well‐studied AT proteins, this nomenclature reveals new commonalities for translocation but also highlights that the autochaperone function is less closely associated with a conserved sequence element than previously believed.
The xylanase inhibitor TAXI‐III counteracts the necrotic activity of a Fusarium graminearum xylanase in vitro and in durum wheat transgenic plants
Authors: Moscetti Ilaria , Faoro Franco , Moro Stefano , Sabbadin Davide , Sella Luca , Favaron Francesco , D'Ovidio Renato
Published: October 2014

The xylanase inhibitor TAXI‐III has been proven to delay Fusarium head blight (FHB) symptoms caused by Fusarium graminearum in transgenic durum wheat plants. To elucidate the molecular mechanism underlying the capacity of the TAXI‐III transgenic plants to limit FHB symptoms, we treated wheat tissues with the xylanase FGSG_03624, hitherto shown to induce cell death and hydrogen peroxide accumulation. Experiments performed on lemmas of flowering wheat spikes and wheat cell suspension cultures demonstrated that pre‐incubation of xylanase FGSG_03624 with TAXI‐III significantly decreased cell death. Most interestingly, a reduced cell death relative to control non‐transgenic plants was also obtained by treating, with the same xylanase, lemmas of TAXI‐III transgenic plants. Molecular modelling studies predicted an interaction between the TAXI‐III residue H395 and residues E122 and E214 belonging to the active site of xylanase FGSG_03624. These results provide, for the first time, clear indications in vitro and in planta that a xylanase inhibitor can prevent the necrotic activity of a xylanase, and suggest that the reduced FHB symptoms on transgenic TAXI‐III plants may be a result not only of the direct inhibition of xylanase activity secreted by the pathogen, but also of the capacity of TAXI‐III to avoid host cell death.
Landscape context influences the abundance of amphibians and the strength of their food web interactions in small ponds
Authors: Burgett Amber A. , Chase Jonathan M.
Published: October 2014

Many species, including most amphibians, undergo an ontogenetic niche shift (ONS) from an aquatic larval stage to a terrestrial adult stage. We use the ratio of aquatic to terrestrial habitat in a landscape as a tool to understand the influence of landscape context on the population growth of ONS species. The aquatic to terrestrial ratio (ATR) of habitats can be viewed as an analog to the influence of resource ratios on the population growth of consumers and depends on the degree to which each habitat type limits the growth of a given population. Population growth rates of shorter‐lived species tend to be more limited by demographic rates in early (aquatic) life stages. As a result, increasing the ATR should lead to a higher total population size in the landscape (and higher densities in the terrestrial habitat), but have little influence on the density of individuals in any given aquatic habitat. Alternatively, population growth rates of longer‐lived species tend to be more limited by demographic rates in later (terrestrial) life stages and increasing the ATR should have little influence on the total population size in the landscape, but decrease the density of individuals in any given aquatic habitat. We show that among‐landscape variation in the breeding‐pond densities of three widespread amphibians with contrasting life histories is consistent with this framework. Within‐pond densities ofPseudacris crucifer, a species with short‐lived adults, were not influenced by ATR, whereas within‐pond densities ofHyla versicolor, a longer‐lived member of the same family (Hylidae), declined as ATR increased.Ambystoma maculatum, a long‐lived salamander, also had lower densities in ponds with higher ATR. BecauseA. maculatumlarvae are important predators in ponds, we use structural equation modeling to show that landscape context (ATR) can moderate community structure via direct (amphibian abundances) and indirect (prey species richness) effects.
“Vanishing Point,” or Reading the Absence
Authors: Doubinsky Sébastien
Published: October 2014

Although they are completely different types of works, Giorgione's painting, La tempesta (1508) and Charles Baudelaire's poem “Correspondances” (1857) from his collection Les fleurs du mal seem to provoke a similar sense of mystery in the viewer/reader. If we can clearly see what the two works “represent” in the sense of images, their meaning and/or purpose seem to evade us when we try to close‐read them. Using a contrastive method inspired by the lingusitic theory of the same name to compare their effect, we will try to show how this artificial proximity can enable us to analyze works that seem to “resist” our hermeneutical desire and build a critical discourse based precisely on this resisting, following in the foosteps of Arnaud Rykner.
La fin du roman et le « sens ultime »
Authors: Alling Annika Mörte
Published: October 2014

Cette étude apporte une nouvelle perspective sur un aspect fondamental et peu étudié du roman Illusions perdues de Balzac, à savoir la problématique autour de la fin et de la clôture. Même si, à première vue, ce roman est « lisible » dans le sens de Roland Barthes, avec un récit plein, achevé et clos, sa fin n'est guère du type « réaliste » qui « va sans dire », selon la formulation de Armine Kotin Mortimer dans La clôture narrative (1985). L'examen sera fait à partir de certaines hypothèses et questions formulées dans les ouvrages généraux sur la fin et la clôture dans les récits narratifs. Que dire en effet du rôle et de l'importance de la fin dans Illusions perdues – et de la relation entre le début et la fin ? Quel est, concrètement, le rapport entre la fin et une sorte de « sens de l'œuvre », constaté par exemple par Mortimer, Peter Brooks (1984), Andrea Del Lungo (2010) et Vincent Jouve (2001).
Mapping self‐reported to behavioral impulsiveness: The role of task parameters
Authors: Lange Florian , Eggert Frank
Published: October 2014

Despite being regarded as indicators of a common psychological capacity, behavioral and self‐reported measures of impulsiveness have been found to barely correlate with each other. Acknowledging the construct's multidimensional nature, the present study set out to map dissociable components of behavioral self‐control (delay discounting, response inhibition) onto lower‐order facets of self‐reported impulsiveness. In addition, we examined whether the relationship between response inhibition and self‐reported impulsiveness depends on the balance between facilitative and interfering priming processes involved in a laboratory task. In two consecutive studies, 185 participants completed laboratory self‐control tasks as well as self‐report questionnaires designed to measure facets of impulsiveness. Correlational analyses revealed an association between subscales of the Barratt Impulsiveness Scale (BIS) and response inhibition in a go/no‐go paradigm involving simultaneously presented task‐irrelevant distractors. This association vanished when an onset asynchrony between distractor and target stimuli was introduced. Previous findings regarding correlations between BIS subscales and delay discounting or intra‐individual response variability could not be replicated. Results indicate that the relationship between response inhibition and self‐reported impulsiveness critically varies as a function of subtle task parameters. Focusing on these procedural details and the multidimensionality of self‐reported impulsiveness might allow for a more differentiated analysis of the convergent validity of self‐control measures.
Unnormalized differences between zeros ofL-functions
Authors: Ford Kevin , Zaharescu Alexandru
Published: October 2014

We study a subtle inequity in the distribution of unnormalized differences between imaginary parts of zeros of the Riemann zeta function, which was observed by a number of authors. We establish a precise measure which explains the phenomenon, that the location of each Riemann zero is encoded in the distribution of large Riemann zeros. We also extend these results to zeros of more general$L$-functions. In particular, we show how the rank of an elliptic curve over$\mathbb{Q}$is encoded in the sequences of zeros ofother$L$-functions, not only the one associated to the curve.
Development of a Low-Cost Parallel Kinematic Machine for Multidirectional Additive Manufacturing
Authors: Song Xuan , Pan Yayue , Chen Yong
Published: October 2014

Most additive manufacturing (AM) processes are layer-based with three linear motions in the X, Y, and Z axes. However, there are drawbacks associated with such limited motions, e.g., nonconformal material properties, stair-stepping effect, and limitations on building-around-inserts. Such drawbacks will limit AM to be used in more general applications. To enable 6-axis motions between a tool and a work piece, we investigated a Stewart mechanism and the feasibility of developing a low-cost 3D printer for the multidirectional fused deposition modeling (FDM) process. The technical challenges in developing such an AM system are discussed including the hardware design, motion planning and modeling, platform constraint checking, tool motion simulation, and platform calibration. Several test cases are performed to illustrate the capability of the developed multidirectional AM system. A discussion of future development on multidirectional AM systems is also given.
On Cutting Temperature Measurement During Titanium Machining With an Atomization-Based Cutting Fluid Spray System
Authors: Hoyne Alexander C. , Nath Chandra , Kapoor Shiv G.
Published: October 2014

The poor thermal conductivity and low elongation-to-break ratio of titanium lead to the development of extreme temperatures (in excess of 550 °C) localized in the tool–chip interface during machining of its alloys. At such temperature level, titanium becomes highly reactive with most tool materials resulting in accelerated tool wear. The atomization-based cutting fluid (ACF) spray system has recently been demonstrated to improve tool life in titanium machining due to good cutting fluid penetration causing the temperature to be reduced in the cutting zone. In this study, the cutting temperatures are measured both by inserting thermocouples at various locations of the tool–chip interface and the tool–work thermocouple technique. Cutting temperatures for dry machining and machining with flood cooling are also characterized for comparison with the ACF spray system temperature data. Findings reveal that the ACF spray system more effectively reduces cutting temperatures over flood cooling and dry conditions. The tool–chip friction coefficient indicates that the fluid film created by the ACF spray system also actively penetrates the tool–chip interface to enhance lubrication during titanium machining.
Numerical Simulation and Optimization of the Thermodynamic Process of the Molten Salt Furnace
Authors: Ning Lian , Fu Dong , Zhou Chenn Q. , Zhou Jiemin
Published: October 2014

In this paper, a numerical model of the molten salt furnace process was developed, by using computational fluid dynamics (CFD) technique and considering the gas flow, the combustion and the radiation heat transfer. The results demonstrate that the performances of the salt furnace could be improved by optimization using the numerical model. The temperatures along the circumference of the furnace coil and outside shell are quite even, and the deviant combustion phenomenon is not observed. A back-flow formed in the upper part of the furnace chamber enhances the circulation and the mixing of the gas and effectively stabilizes the combustion in the furnace. The behaviors of CO, CO2, NOx, and H2O are presented in terms of the gas flow, temperature distribution and volumetric concentration distribution. It is concluded that the furnace with the constant air flow rate of 15,500 Nm3/h and the guiding vane angle at 48–50 deg is optimized for the combustion effectiveness.
Friction and Wear of Potassium Titanate Whisker Filled Carbon Fabric/Phenolic Polymer Composites
Authors: Zhang Xinrui , Pei Xianqiang , Wang Qihua , Wang Tingmei
Published: October 2014

Carbon fabric/phenolic composites modified with potassium titanate whisker (PTW) were prepared by a dip-coating and hot-press molding technique, and the tribological properties of the resulting composites were investigated systematically using a ring-on-block arrangement under different sliding conditions. Experimental results showed that the optimal PTW significantly decreased the wear-rate. The worn surfaces of the composites and the transfer film formed on the counterpart steel ring were examined by scanning electron microscopy (SEM) to reveal the wear mechanisms. The transfer films formed on the counterpart surfaces made contributions to the improvement of the tribological behavior of the carbon fabric composites. The friction and wear of the filled carbon fabric composites was significantly dependent on the sliding conditions. It is observed that the wear-rate increased with increasing applied load and sliding speeds.
Design of a Solar Reactor to Split CO2 Via Isothermal Redox Cycling of Ceria
Authors: Bader Roman , Bala Chandran Rohini , Venstrom Luke J. , Sedler Stephen J. , Krenzke Peter T. , De Smith Robert M. , Banerjee Aayan , Chase Thomas R. , Davidson Jane H. , Lipiński Wojciech
Published: October 2014

The design procedure for a 3 kWth prototype solar thermochemical reactor to implement isothermal redox cycling of ceria for CO2 splitting is presented. The reactor uses beds of mm-sized porous ceria particles contained in the annulus of concentric alumina tube assemblies that line the cylindrical wall of a solar cavity receiver. The porous particle beds provide high surface area for the heterogeneous reactions, rapid heat and mass transfer, and low pressure drop. Redox cycling is accomplished by alternating flows of inert sweep gas and CO2 through the bed. The gas flow rates and cycle step durations are selected by scaling the results from small-scale experiments. Thermal and thermo-mechanical models of the reactor and reactive element tubes are developed to predict the steady-state temperature and stress distributions for nominal operating conditions. The simulation results indicate that the target temperature of 1773 K will be reached in the prototype reactor and that the Mohr–Coulomb static factor of safety is above two everywhere in the tubes, indicating that thermo-mechanical stresses in the tubes remain acceptably low.
Modeling of Hybrid Cooling Systems for Shipboard Application
Authors: Cao Tao , Lee Hoseong , Hwang Yunho , Radermacher Reinhard
Published: October 2014

A vapor compression cycle (VCC) powered by the diesel generator is typically used in space cooling for the shipboard application. This system consumes large amounts of electricity. In an effort to reduce fuel consumption for cooling, two solar powered hybrid cooling system options are proposed. The first one is to use VCC with solar photovoltaic (PV) panels and the second one is to use absorption cycle (ABC) with evacuated thermal collectors (ETC). Control strategies have been set up for all three scenarios to provide space cooling for guest rooms on a cruise ship. In addition, for the PV powered VCC case, the optimum battery storage system size was investigated. It was found that the optimized PV system could reduce yearly fuel consumption and life time greenhouse gas (GHG) emission by 98% and 93%, respectively. The ETC powered ABC system would reduce the fuel consumption and GHG emission by 78% and 75%, respectively. The cost analysis indicates that the ETC system has lowest life time cost, which is 28% of the baseline scenario and 23% of the PV system.
Characterization of the Thermal Behavior of the Materials Commonly Used in Colombia for the Construction of Building Envelopes
Authors: Vélez Eduardo , Amaya Fabián , Olmos Antonio , Pérez Raúl , Bula Antonio , Sanjuan Marco
Published: October 2014

The thermal performance of building materials used in Colombia is not currently characterized, which is essential to obtain the necessary information for an architectural design based on energy efficiency. The determination of materials thermal properties, as well as thermal and energy performance of building materials commonly used in Colombia are the main challenges for this research. The proposed methodology implies the experimental determination of the different materials thermal properties through the design and construction of an experimental device capable to accommodate different materials configurations. This will allow us to obtain relevant information to develop the government’s energy standards for quality building materials and quality policies for private companies. Among others are included: the Environmental Seal for Sustainable Building, which is currently being developed by the Colombian Council of Sustainable Building (CCCS); the Colombian standard for thermal systems applications in buildings (RITE) currently being developed by the Colombian Association of Air Conditioning and Refrigeration (ACAIRE); and policies for national sustainable buildings that were included in the National Development Plan 2010–2014 and 2015–2019.
Robust Heat Transfer Enhancement During Melting and Solidification of a PCM Using a Combined Heat Pipe-Metal Foam or Foil Configuration
Authors: Allen Michael J. , Faghri Amir , Bergman Theodore L.
Published: October 2014

Experiments are performed to analyze melting and solidification of a phase change material (PCM) enclosed in a vertical cylinder by a concentrically-located heat pipe (HP) surrounded by either aluminum foam or foils. The liquid fraction, temperature distribution, melting (solidification) rates and effectiveness are reported to quantify the improvement in performance relative to a base case, a Rod-PCM configuration. Parameters of interest include the porosity of the PCM-metal composite, the foil thickness, the number of foils and the foam pore density. The main contributor to enhanced performance is shown to be the porosity for both the HP-Foil-PCM and HP-Foam-PCM configurations. Both of these configurations improve heat transfer rates relative to either the HP-PCM or the Rod-PCM configuration. However, the HP-Foil-PCM configuration is shown to have approximately the same performance as the HP-Foam-PCM configuration with one third of the metal mass, for the range of porosities studied here (0.870 to 0.987). The HP-Foil-PCM configuration, with a porosity of 0.957 using 162 foils of thickness 0.024 mm, attained an overall rate of phase change that is about 15 times greater than that of the Rod-PCM configuration and about 10 times greater than that of the HP-PCM configuration. The greatest degree of enhancement was achieved with the HP-Foil-PCM configuration (with porosity 0.957) yielding an average effectiveness during melting (solidification) of 14.7 (8.4), which is an extraordinary improvement over the base case.
Comparative Performance of Two Prototypes of a Passive Solar Heat Pipe System
Authors: Robinson Brian S. , Sharp M. Keith
Published: October 2014

Thermal performance of an improved passive solar heat pipe system was directly compared to that of a previous prototype. Simulated and experimental results for the first prototype established baseline performance. Subsequently, potential improvements were simulated, and a second prototype was built and tested along side the first. The system uses heat pipes for high rates of heat transfer into the building, and limited losses in the reverse direction. The evaporator section of each heat pipe is attached to a glass-covered absorber on the outside of a south wall, and the slightly elevated condenser section is either immersed in water in a thermal storage tank or exposed to air in the room. Two-phase flow occurs in the heat pipe only when the evaporator is warmer than the condenser, creating a thermal diode effect. Computer simulations showed that system performance could be improved by using thicker insulation between the absorber and the storage tanks, and by switching from a copper to a rubber adiabatic section, which both reduced heat losses to ambient from the storage tanks. Early morning heating was improved by exposing one of five condensers directly to room air, which also improved overall system efficiency. A copper solar absorber soldered to the copper evaporator section improved heat conduction compared to the previous aluminum absorber bonded to the copper evaporator. Together these modifications improved simulated annual solar fraction by 20.8%. The new prototype incorporating these changes was tested along side the previous prototype in a two-room passive solar test facility during January through February of 2013. Temperatures were monitored with thermocouples at multiple locations throughout the systems, in each room and outdoors. Insolation was measured by four pyranometers attached to the building. Results showed that the design modifications implemented for the new model increased thermal gains to storage and to the room, and decreased thermal losses to ambient. The load-to-collector ratio for the experiments was 2.7 times lower than for the simulations, which decreased the potential for experimental improvements compared to the simulated improvements. However, average daily peak efficiency for the new system was 85.0%, compared to 80.7% for the previous system. Furthermore, the average storage temperature over the entire testing period for the new model was 13.4% higher than that of the previous model, while the average room temperature over the same period was 24.6% greater for the new system.
Comparison of Energy Storage Methods for Solar Electric Production
Authors: Shakeri Mostafa , Soltanzadeh Maryam , Berson R. Eric , Sharp M. Keith
Published: October 2014

Energy storage is key to expanding the capacity factor for electric power from solar energy. To accommodate variable weather patterns and electric demand, storage may be needed not just for diurnal cycles, but for variations as long as seasonal. Five solar electric systems with energy storage were simulated and compared, including an ammonia thermochemical energy storage cycle, compressed air energy storage (CAES), pumped hydroelectric energy storage (PHES), vanadium flow battery, and thermal energy storage (TES). To isolate the influence of the storage system, all systems used the same parabolic concentrator and Stirling engine. For CAES, PHES and battery, the engine directly produced electricity, which was then converted and stored. For TES, heat transfer fluid was heated by the dish and stored, and later used to drive the engine to produce electricity. For ammonia, the dish heated an ammonia dissociation reactor to produce nitrogen and hydrogen, which was stored. Heat was recovered to drive the engine by reforming ammonia from the stored gases. Each system was simulated in TRNSYS with weather data for Louisville, KY and Phoenix, AZ with subsystem efficiencies and storage losses estimated from previous experimental results. All systems including the ammonia cycle involved time dependent storage losses. Losses from the receiver included convection and emitted radiation, both of which depend on receiver temperature.

Overall (solar-storage-electric) efficiency of the ammonia cycle depended strongly on synthesis reactor temperature, ranging from less than 1% to ∼18% for both Louisville, KY and Phoenix, AZ, at 500 K to 800 K, respectively. In contrast, the effect of dissociation reactor temperature was less. Overall (solar-electric-storage-electric) efficiencies of the CAES, systems in the limit of zero storage time ranged from ∼10% to ∼18% for solar receiver temperature of 500 K to 800 K. The vanadium flow battery and PHES efficiencies ranged from ∼9% to ∼17% for the same conditions. TES initially provided 12 to 23% efficiency over the same range of temperature. When time-dependent storage losses were included, however, efficiencies for all systems declined rapidly except the ammonia cycle in both locations and PHES in Louisville. The ammonia system had the highest efficiency after one month of storage, an advantage that increased with time of storage.

The simulations showed that TES was most efficient for diurnal-scale storage and the ammonia cycle for longer storage. Full capacity factor for solar electric production may be most efficiently accomplished with a combination of direct solar-electric production and systems with both diurnal and long-term storage, the proportions of which depending on weather conditions and electric demand profiles.
Application of Transparent Conductive Oxides Films for High-Temperature Solar Selective Absorbers
Authors: Shimizu Makoto , Suzuki Mari , Kohiyama Asaka , Iguchi Fumitada , Yugami Hiroo
Published: October 2014

At present, the utilization of thermal energy from sunlight has been widely adopted as the working principle of concentrated solar power (CSP) generation systems. In this research, we suggest a CSP technology based on the properties of transparent conductive oxide (TCO) films on metal substrates which is compatible with mass production of solar selective absorbers that can be utilized at high temperatures. TCO material has plasma wavelength in infrared region. Therefore the electromagnetic wave with shorter wavelength than plasma wavelength goes through the material, while the electromagnetic wave with longer wavelength is reflected on the surface. By coating metal surface with a TCO film, interference is occurred in transparent wavelength range of TCO. Therefore, solar energy is highly absorbed, though thermal radiation from the absorber is suppressed. The optical property of fabricated TCO coated metal is well consistent with the simulated property. It is revealed that the performance of the absorber is improved by fabricating microstructures on the metal substrate. Thermal stability is confirmed at 700°C in vacuum for 3 hours. Solar absorptance and hemispherical emittance of the fabricated absorber are 0.82 and 0.17, respectively, which is comparable to that of commercialized absorbers.
Operation Strategies of BCHP Systems Based on Gas-Engines
Authors: Ma Yufei , Liu Lanbin
Published: October 2014

The operation strategies are key points that can influence the annual total energy efficiency, energy saving efficiency and economic benefits of BCHP systems. This paper mainly aims at establishing the model about how to realize several typical operation strategies of BCHP systems based on gas engines, such as operation following the power load and operation following the heating load. Also, in a specific project, operation strategies always depend on the load feature and the government policy and the price of power and etc. This paper includes methods about how to choose the operation strategies reasonably.
New Thermal Energy Storage Materials From Industrial Wastes: Compatibility of Steel Slags With the Most Common Heat Transfer Fluids
Authors: Ortega Iñigo , Rodríguez-Aseguinolaza Javier , Gil Antoni , Faik Abdessamad , D’Aguanno Bruno
Published: October 2014

Slag is one of the main waste materials of the iron and steel manufacturing. Every year about 20 million tons of slag are generated in the United States and 43.5 million tons in Europe. The revalorization of this by-product as heat storage material in thermal energy storage systems would have numerous advantages which include: the possibility to extend the working temperature range up to 1000 °C, the reduction of the system cost and, at the same time, the decrease of the quantity of waste in the iron and steel industry.

In this paper, two different electric arc furnace slags from two companies located in the Basque Country (Spain) are studied. Their thermal stability and compatibility in direct contact with the most common heat transfer fluids used in the concentrated solar power plants are analyzed. The experiments have been designed in order to cover a wide temperature range up to the maximum operation temperature of the future generation of concentrated solar power plants (1000 °C). In particular, three different fluids have been studied: synthetic oil (Syltherm 800®) at 400 °C, molten salt (Solar Salt) at 500 °C and air at 1000 °C. In addition, a complete characterization of the studied slags and fluids used in the experiments is presented showing the behavior of these materials after 500 hour laboratory-tests.
Developing a Model to Predict the Torrefaction of Biomass
Authors: Mahutga Ryan R. , Gent Stephen P. , Twedt Michael P.
Published: October 2014

With increasing fuel costs and more emphasis being placed on sustainable sources of energy, biomass from agricultural residues and energy crops are becoming an increasingly viable value-added resource for the rural economies in United States and throughout the world. Torrefaction, a thermochemical reaction process, is a form of mild-pyrolysis that improves the qualities of biomass feedstocks for use as a fuel similar to charcoal. This research presents a user-centered computational framework to predict the effects of torrefaction of biomass. The reaction model is based on recently developed models for the torrefaction of willow. The basis for this model is a two stage, solid mass loss kinetics reaction where Arrhenius kinetic parameters are estimated based on experimentally obtained TGA data. Utilizing these parameters along with solid product formation equations it is possible to determine the solid mass yield, as well as the yields of the two stages of pseudo-volatiles released during reaction. Chemical species composition of the volatiles is determined from a system of constrained linear equations based on calculated volatile yield data and experimental results. The reaction model is implemented into MATLAB R2012b as a standalone program with a graphical user interface to obtain inputs, and display numeric and graphic results. The overall goal of this model is to provide a guide for improving conversion efficiency of biomass to bio-char.
Numerical Modeling of Thermal Energy Storage System
Authors: Bellan Selvan , Gonzalez-Aguilar Jose , Romero Manuel , Rahman Muhammad M. , Goswami D. Yogi , Stefanakos Elias K.
Published: October 2014

Thermal energy storage in the form of latent heat of fusion of phase change material gained considerable attention in solar energy applications since it significantly increases the energy density and reduces the storage tank size compared to the sensible heat storage system. Several numerical and experimental studies have been conducted to enhance the performance of the system. In this study, 2-D continuous solid phase and effective packed bed models are developed to study the behavior and performance of a thermal energy storage system for high temperature applications, which is composed of spherical capsules encapsulated by phase change material (Sodium nitrate) and high temperature synthetic oil (Therminol 66) as heat transfer fluid. Temperature distribution, fluid flow, melting, solidification and thermocline behavior of the system are predicted and the influence of capsule size on the performance of the system is studied.
Understanding the Impacts of Local Policies on Distributed Photovoltaic Market Development
Authors: Doris Elizabeth , Booth Sarah , Chavez Joseph , Krasko Vitaliy , Stout Sherry
Published: October 2014

A growing body of literature discusses the impacts of state-level policies on the development of distributed photovoltaic (PV) markets both in the implementing jurisdictions and spilling into others. Localities (municipalities and counties) are also increasing their involvement in policy development to support clean energy markets. There is a barrier to knowing the impacts of the policies within a jurisdiction as well as how the patchwork of local policies interacts to contribute to national PV market developments. This barrier can result in an inability for localities to implement effective and efficient local policies. This paper aims to reduce this barrier by (1) summarizing local activities related to solar in 151 localities as a means of determining trends in local PV policy action, (2) looking critically at several local policy environments in two states to determine if successful policy strategies or interesting observations warrant further investigation on the impacts of local policy, and (3) outlining the challenges of and opportunities for developing improved data for supporting an understanding of local policy impacts on the national market.
An Overview of Brazilian Nuclear Program
Authors: Almeida Renata A. , Moreira Maria de Lourdes
Published: October 2014

Human dependence on electricity has increased greatly over the years and, as a result, access to energy resources has become a priority in most countries, both developed and developing. With this expansion comes the need for government involvement in the planning and expansion of energy resources, especially when it comes to nuclear energy. This study presents a review of Brazil’s nuclear power program with the Angra 1 and Angra 2 power plants and the construction of the Angra 3 plant. It examines the Plano Nacional de Energia (National Energy Plan – NEP-2030) which aims, among other objectives, to implement a revised nuclear energy program, including the construction of new power plants in locations yet to be determined throughout the country.
Design, Fabrication, and Performance Test of R32-OTEC Pilot Plant
Authors: Kim Hyeon-Ju , Lee Ho-Saeng , Jung Young-Kwon , Cha Sang-Won , Moon Deok-Soo
Published: October 2014

In this paper, we present the results of the design, fabrication, installation, and operation of a 20-kW OTEC (ocean thermal energy conversion) pilot plant. The results can be used as basic data for the design of commercial plants with capacities in excess of 40 MW. To perform an experiment on the 20 kW OTEC, a closed OTEC cycle was designed and fabricated at the Ocean Water Plant Research Center. The cycle utilizes surface ocean water as its heat source and deep ocean water as its heat sink. R32 (Difluoromethane, CH2F2) was used as the working fluid, and the temperature of the heat source and heat sink were 26°C and 5°C, respectively. A semi-welded-type heat exchanger was used as the evaporator and condenser, and the OTEC cycle was designed for a gross power of 20 kW. The advantages of the semi-welded-type heat exchanger include easy maintenance of the gasket-type heat exchanger and the rare leakage of the welded-type heat exchanger. The plate arrangement of the semi-welded-type heat exchanger comprised one welded channel for the working fluid and another gasket-type channel. The gross power of the turbine was determined to be 20.49 kW. The evaporating capacity was calculated as 1,020 kW, and the cycle efficiency was determined to be about 2.00%.