bluuebunny/crossref_metadata_2025 huggingface dataset:
Genetic basis and fitness correlates of dynamic carotenoid‐based ornamental coloration in male and female common kestrels Falco tinnunculus
Authors: Vergara P. , Fargallo J. A. , Martínez‐Padilla J.
Published: November 2014

Knowledge of the genetic basis of sexual ornaments is essential to understand their evolution through sexual selection. Although carotenoid‐based ornaments have been instrumental in the study of sexual selection, given the inability of animals to synthesize carotenoids de novo, they are generally assumed to be influenced solely by environmental variation. However, very few studies have directly estimated the role of genes and the environment in shaping variation in carotenoid‐based traits. Using long‐term individual‐based data, we here explore the evolutionary potential of a dynamic, carotenoid‐based ornament (namely skin coloration), in male and female common kestrels. We first estimate the amount of genetic variation underlying variation in hue, chroma and brightness. After correcting for sex differences, the chroma of the orange‐yellow eye ring coloration was significantly heritable (h2 ± SE = 0.40 ± 0.17), whereas neither hue (h2 = 0) nor brightness (h2 = 0.02) was heritable. Second, we estimate the strength and shape of selection acting upon chromatic (hue and chroma) and achromatic (brightness) variation and show positive and negative directional selection on female but not male chroma and hue, respectively, whereas brightness was unrelated to fitness in both sexes. This suggests that different components of carotenoid‐based signals traits may show different evolutionary dynamics. Overall, we show that carotenoid‐based coloration is a complex and multifaceted trait. If we are to gain a better understanding of the processes responsible for the generation and maintenance of variation in carotenoid‐based coloration, these complexities need to be taken into account.
Higher mortality after myocardial infarction in patients with severe mental illness: a nationwide cohort study
Authors: Bodén R. , Molin E. , Jernberg T. , Kieler H. , Lindahl B. , Sundström J.
Published: November 2014

Objectives

The aim of this study was to explore the impact of severe mental illness (SMI) on myocardial infarction survival and determine the influence of risk factor burden, myocardial infarction severity and different treatments.

Design, setting and participants

This population‐based cohort study, conducted in Sweden during the period 1997–2010, included all patients with a first diagnosis of myocardial infarction in the Swedish nationwide myocardial infarction register SWEDEHEART (n = 209 592). Exposure was defined as a diagnosis of SMI (i.e. bipolar disorder or schizophrenia) in the national patient register prior to infarction. Bias‐minimized logistic regression models were identified using directed acyclic graphs and included covariates age, gender, smoking, diabetes, previous cardiovascular disease, myocardial infarction characteristics and treatment.

Main outcome measures

The outcomes were 30‐day and 1‐year mortality, obtained through linkage with national population registers.

Results

Patients with bipolar disorder (n = 442) and schizophrenia (n = 541) were younger (mean age 68 and 63 years, respectively) than those without SMI (n = 208 609; mean age 71 years). The overall 30‐day and 1‐year mortality rates were 10% and 18%, respectively. Compared with patients without SMI, patients with SMI had higher 30‐day [odds ratio (OR) 1.99, 95% confidence interval (CI) 1.55–2.56] and 1‐year mortality (OR 2.11, 95% CI 1.74–2.56) in the fully adjusted model. The highest mortality was observed amongst patients with schizophrenia (30‐day mortality: OR 2.58, 95% CI 1.88–3.54; 1‐year mortality: OR 2.55, 95% CI 1.98–3.29).

Conclusion

SMI is associated with a markedly higher mortality after myocardial infarction, also after accounting for contributing factors. It is imperative to identify the reasons for this higher mortality.
Institution Building and Political Accountability
Authors: MAJUMDAR SUMON , MUKAND SHARUN W.
Published: November 2014

The paper examines the role of policy intervention in catalyzing institutional change. We identify two effects of development policy as a tool for institutional change. By increasing political accountability, it may encourage nascent democratic governments to invest in good institutions. However, it also increases incentives of the rentier elite to tighten their grip on political institutions. Which of these effects dominate determine if development policy will lead to democratic consolidation and economic improvement or to the worsening of existing institutions. If the elite are deeply entrenched, then modernization may require combining development policy with subsidies.
Contractually Stable Alliances
Authors: MAULEON ANA , SEMPERE‐MONERRIS JOSE J. , VANNETELBOSCH VINCENT
Published: November 2014

We analyze how different rules for exiting an alliance affect the formation of strategic alliances. We adopt the concept of contractual stability to predict the alliances that are going to emerge in the long run. We find that any asymmetric alliance structure consisting of two alliances is contractually stable under the unanimity decision rule. In addition, the grand alliance which is the efficient structure is stable. If we allow for side payments to compensate former partners, then some less efficient structures that were stable without side payments are no longer stable. Moreover, we show that the stability of alliances under the unanimity rule to exit is robust to the type of firms, myopic or farsighted. Finally, there is no contractually stable alliance structure under the simple majority decision rule.
Effects of stomatal density and leaf water content on the 18O enrichment of leaf water
Authors: Larcher Leticia , Hara‐Nishimura Ikuko , Sternberg Leonel
Published: November 2014

Leaf water isotopic composition is imprinted in several biomarkers of interest and it is imperative that we understand the isotopic enrichment of leaf water. Here, we test the effect of stomatal density and leaf water content on the oxygen isotopic composition of leaf water in transgenic Arabidopsis plants expressing different stomatal densities, and several other species showing a range of stomatal density.

We grew Arabidopsis plants hydroponically and collected other species in the field. Stomatal density and leaf water content were determined for each plant. We measured transpiration and extracted leaf water for isotopic determination. Using these measurements and the current leaf water isotope model, we calculated several of the parameters related to leaf water isotopic enrichment.

High stomatal density promoted leaf water isotope enrichment. No conclusion, however, can be drawn regarding the effect of leaf water content on leaf water isotope enrichment. Factors such as transpiration might mask the effect of stomatal density on leaf water isotopic enrichment.

We propose a method by which stomatal density can be incorporated in the current Peclet model of leaf water isotope enrichment. These findings have important applications in the use of plant‐based metabolic proxies in paleoclimate studies.
Three causes of variation in the photochemical reflectance index (PRI) in evergreen conifers
Authors: Wong Christopher Y. S. , Gamon John A.
Published: November 2014

The photochemical reflectance index (PRI) reflects diurnal xanthophyll cycle activity and is also influenced by seasonally changing carotenoid : Chl pigment ratios. Both changing pigment pools and xanthophyll cycle activity contribute to photoprotection in evergreen conifers exposed to boreal winters, but they operate over different timescales, and their relative contribution to the PRI signal has often been unclear.

To clarify these responses and their contribution to the PRI signal, leaf PRI, pigment composition, temperature and irradiance were monitored over 2 yr for two evergreen conifers (Pinus contorta and Pinus ponderosa) in a boreal climate.

PRI was affected by three distinct processes operating over different timescales and exhibiting contrasting spectral responses. Over the 2 yr study period, the greatest change in PRI resulted from seasonally changing carotenoid : Chl pigment ratios, followed by a previously unreported shifting leaf albedo during periods of deep cold. Remarkably, the smallest change was attributable to the xanthophyll cycle.

To properly distinguish these three effects, interpretation of PRI must consider temporal context, physiological responses to evolving environmental conditions, and spectral response. Consideration of the separate mechanisms affecting PRI over different timescales could greatly improve efforts to monitor changing photosynthetic activity using optical remote sensing.
Repression of flowering under a noninductive photoperiod by the HDA9‐AGL19‐FT module in Arabidopsis
Authors: Kang Min‐Jeong , Jin Hong‐Shi , Noh Yoo‐Sun , Noh Bosl
Published: November 2014

Posttranslational acetylation of histones is reversibly regulated by histone deacetylases (HDACs). Despite the evident significance of HDACs in Arabidopsis development, the biological roles and underlying molecular mechanisms of many HDACs are yet to be elucidated.

By a reverse‐genetic approach, we isolated an hda9 mutant and performed phenotypic analyses on it. In order to address the role of HDA9 in flowering, genetic, molecular, and biochemical approaches were employed.

hda9 flowered early under noninductive short‐day (SD) conditions and had increased expression of the floral integrator FLOWERING LOCUS T (FT) and the floral activator AGAMOUS‐LIKE 19 (AGL19) compared with the wild‐type. The hda9 mutation increased histone acetylation and RNA polymerase II occupancy at AGL19 but not at FT during active transcription, and the HDA9 protein directly targeted AGL19. AGL19 expression was higher under SD than under inductive long‐day (LD) conditions, and an AGL19 overexpression caused a strong up‐regulation of FT. A genetic analysis showed that an agl19 mutation is epistatic to the hda9 mutation, masking both the early flowering and the increased FT expression of hda9.

Taken together, our data indicate that HDA9 prevents precocious flowering under SD conditions by curbing the hyperactivation of AGL19, an upstream activator of FT, through resetting the local chromatin environment.
Altered lipid composition and enhanced lipid production in green microalga by introduction of brassica diacylglycerol acyltransferase 2
Authors: Ahmad Irshad , Sharma Anil K. , Daniell Henry , Kumar Shashi
Published: November 2014

Higher lipid biosynthesis and accumulation are important to achieve economic viability of biofuel production via microalgae. To enhance lipid content, Chlamydomonas reinhardtii was genetically engineered with a key enzyme diacylglycerol acyltransferase (BnDGAT2) from Brassica napus, responsible for neutral lipid biosynthesis. The transformed colonies harbouring aph7 gene, screened on hygromycin‐supplemented medium, achieved transformation frequency of ~120 ± 10 colonies/1 × 106 cells. Transgene integration and expression were confirmed by PCR, Southern blots, staining lipid droplets, proteins and spectro‐fluorometric analysis of Nile red‐stained cells. The neutral lipid is a major class (over 80% of total lipids) and most significant requirement for biodiesel production; this was remarkably higher in the transformed alga than the untransformed control. The levels of saturated fatty acids in the transformed alga decreased to about 7% while unsaturated fatty acids increased proportionately when compared to wild type cells. Polyunsaturated fatty acids, especially α‐linolenic acid, an essential omega‐3 fatty acid, were enhanced up to 12% in the transformed line. Nile red staining confirmed formation of a large number of lipid globules in the transformed alga. Evaluation of long‐term stability and vitality of the transgenic alga revealed that cryopreservation produced significantly higher quantity of lipid than those maintained continuously over 128 generations on solid medium. The overexpression of BnDGAT2 significantly altered the fatty acids profile in the transformed alga. Results of this study offer a valuable strategy of genetic manipulation for enhancing polyunsaturated fatty acids and neutral lipids for biofuel production in algae.
Nationwide survey of coronary aneurysms with diameter >6 mm in Kawasaki disease in Korea
Authors: Jang Gi Young , Kang I‐seok , Choi Jae Young , Bae Eun Jung , Kim Young‐Hwue , Kim Seong Ho , Ma Jae Sook
Published: November 2014

Background

We investigated the course of coronary aneurysm with diameter >6 mm in Kawasaki disease (KD), as well as related therapeutic trends and prognosis in Korea.

Methods

A nationwide questionnaire survey was carried out in 77 hospitals, to investigate, retrospectively, patients with KD who had coronary aneurysms with a diameter >6 mm between 1990 and 2011.

Results

The median age of onset was 3 years (range, 2 months–16 years) in a total of 239 patients. During the acute stage of KD, most patients received i.v. immunoglobulins and aspirin. In addition, 27 patients received steroid therapy. In the current study, the mean coronary aneurysm size was 8.7 ± 3.2 mm (range, 6–21 mm). Twenty‐two patients underwent interventional catheterization. Procedures included percutaneous transluminal coronary balloon angioplasty (n = 10), stent placement (n = 9), and percutaneous transluminal coronary rotational ablation (n = 3). Fourteen patients underwent coronary artery bypass graft surgery. Of the 239 patients who had coronary aneurysms with diameter >6 mm, 13 (5.4%) presented with findings suggestive of myocardial infarction. Five patients died during the follow‐up period.

Conclusions

Severe stenosis or occlusion of the coronary artery may occur in some patients who develop coronary aneurysms with diameter >6 mm; early management such as coronary interventions or surgery should be considered in such cases.
Concentrations of metals and potential metal‐binding compounds and speciation of Cd, Zn and Cu in phloem and xylem saps from castor bean plants (Ricinus communis) treated with four levels of cadmium
Authors: Hazama Kenji , Nagata Shinji , Fujimori Tamaki , Yanagisawa Shuichi , Yoneyama Tadakatsu
Published: November 2014

We examined the concentrations of metals (Cd, Zn, Cu, Fe and Mn) and potential metal‐binding compounds [nicotianamine (NA), thiol compounds and citrate] in xylem and phloem saps from 4‐week‐old castor bean plants (Ricinus communis) treated with 0 (control), 0.1, 1.0, and 10 μM Cd for 3 weeks. Treatment with 0.1 and 1 μM Cd produced no visible damage, while 10 μM Cd retarded growth. Cadmium concentrations in both saps were higher than those in the culture solution at 0.1 μM, similar at 1.0 μM and lower at 10 μM. Cd at 10 μM reduced Cu and Fe concentrations in both saps. NA concentrations measured by capillary electrophoresis‐mass spectrometry (MS) in xylem sap (20 μM) were higher than the Cu concentrations, and those in phloem sap (150 μM) were higher than those of Zn, Fe and Cu combined. Reduced glutathione concentrations differed in xylem and phloem saps (1–2 and 30–150 μM, respectively), but oxidized glutathione concentrations were similar. Phloem sap phytochelatin 2 concentration increased from 0.8 μM in controls to 8 μM in 10 μM Cd. Free citrate was 2–4 μM in xylem sap and 70–100 μM in phloem sap. Total bound forms of Cd in phloem and xylem saps from 1 μM Cd‐treated plants were 54 and 8%, respectively. Treatment of phloem sap with proteinaseK reduced high‐molecular compounds while increasing fractions of low‐molecular Cd–thiol complexes. Zinc‐NA, Fe‐NA and Cu‐NA were identified in the phloem sap fraction of control plants by electrospray ionization time‐of‐flight MS, and the xylem sap contained Cu‐NA.
Effects of Addition of Tissue‐Type Plasminogen Activator in In Vitro Fertilization Medium on Bovine Embryo Development and Quality
Authors: Krania F , Dovolou E , Rekkas CA , Theodosiadou EK , Pappas I , Amiridis GS
Published: November 2014

Contents

Plasminogen activators/Plasmin system plays pivotal role in regulating reproductive functions of mammals. Here, we examined the effects of modification of in vitro fertilization medium (IVF medium) with the addition of tissue‐type plasminogen activator (t‐PA), on bovine embryo development and quality, assessed by quantification of expression of various genes related to metabolism, oxidation, implantation and apoptosis. In addition, plasminogen activator activity (PAA) and plasminogen activator inhibition (PAI) were measured in the spent media. After conventional IVM, 2016 cumulus‐oocyte complexes (COCs) were divided into four groups with modified composition of the IVF medium containing t‐PA and/or its inhibitor epsilon‐aminocaproic acid (control, t‐PA, t‐PA+ε‐ACA, ε‐ACA). Presumptive zygotes were cultured for 8 days in synthetic oviductal fluid (SOF) medium; gene expression studies were carried out on morulae and blastocysts. t‐PA alone significantly suppressed cleavage and blastocyst formation rates, but this effect was neutralized by the addition of ε‐ACA. PAA in the treated group was significantly reduced by ε‐ACA, but without total elimination. Significant differences were detected in the expression of genes related to apoptosis and/or cell cycle arrest (BAX, BCL2L1, KAT2B) between embryos produced in t‐PA‐modified media and controls, giving an overall notion that the inferior developmental competence of treated embryos may be attributed to apoptotic phenomena induced by t‐PA. In conclusion, it appears that excessive t‐PA content in the IVF media, suppresses blastocyst formation rate, possibly due to induction of apoptotic phenomena.
International Trade Disputes on Renewable Energy: Testing Ground for the Mutual Supportiveness of WTO Law and Climate Change Law
Authors: Kulovesi Kati
Published: November 2014

This article explores the relationship between renewable energy support policies and World Trade Organization (WTO) law on unfair trade practices. It analyzes the Canada‐Renewable Energy case at the WTO, where an open conflict between trade rules and climate policy was arguably avoided only through a heavily criticized interpretation of the definition of subsidies by the WTO dispute settlement bodies. It draws attention to broader challenges in the relationship between renewable energy support policies and the current WTO subsidies law. The article also discusses the AD590‐Solar Panels trade dispute between the European Union and China, examining the complex relationship between cheap solar panel exports, anti‐dumping duties and EU climate policy objectives.
The key role of global solid‐Earth processes in preconditioning Greenland's glaciation since the Pliocene
Authors: Steinberger Bernhard , Spakman Wim , Japsen Peter , Torsvik Trond H.
Published: November 2014

After >500 Ma of absence, major Northern Hemisphere glaciations appeared during the Plio‐Pleistocene, with Greenland leading other northern areas. Here, we propose that three major solid‐Earth processes underpinned build‐up of the Greenland ice‐sheet. First, a mantle‐plume pulse, responsible for the North Atlantic Igneous Province at ~60 Ma, regionally thinned the lithosphere. Younger plume pulses led to uplift, which accelerated at ~5 Ma, lifting the parts of the East Greenland margin closest to Iceland to elevations of more than 3 km above sea level. Second, plate‐tectonic reconstruction shows a ~6° northward component of Greenland motion relative to the mantle since ~60 Ma. Third, a concurrent northward rotation of the entire mantle and crust towards the pole, dubbed True Polar Wander (TPW), contributed an additional ~12° change in latitude. These global geodynamic processes preconditioned Greenland to sustain long‐term glaciation, emphasizing the role of solid‐Earth processes in driving long‐term global climatic transitions.
Vaccination guidelines after hematopoietic stem cell transplantation: practitioners' knowledge, attitudes, and gap between guidelines and clinical practice
Authors: Ariza‐Heredia E.J. , Gulbis A.M. , Stolar K.R. , Kebriaei P. , Shah D.P. , McConn K.K. , Champlin R.E. , Chemaly R.F.
Published: November 2014

Background

Hematopoietic stem cell transplant (HCT) recipients are more susceptible to infections from vaccine‐preventable diseases than the general population. Despite the development of international consensus guidelines addressing immunization after HCT, studies have shown that deviations from recommended immunization practices commonly occur.

Methods

An anonymous survey aimed at determining awareness of the guidelines and attitudes toward vaccination was distributed to our HCT clinicians. In parallel, we retrospectively evaluated patients' characteristics and post‐HCT vaccine administration practices from 2010 to 2013.

Results

The majority of survey respondents (96%) were familiar with post‐HCT vaccination protocols. Seventy‐four percent of respondents reported that influenza vaccines were given to >70% of their patients, and 41% stated that they prescribed live vaccines to eligible patients. However, our pharmacy database review revealed that 38% of patients received the first series of vaccinations by the recommended 6 months post HCT, and 60% received them by 1 year after HCT. Most patients who had their vaccines withheld had relapsed disease or were undergoing treatment for graft‐versus‐host disease. Furthermore, we identified lower immunization rates in non‐English speaking individuals, African‐Americans, and Hispanic patients.

Conclusions

Survey respondents reported being aware of current guidelines; however, adherence to the recommendations varied, likely connected to conflicting data on vaccine effectiveness and a lack of clear recommendations in complex clinical scenarios. Similar to the general population, patient barriers also could have contributed to lower vaccination rates in some cases. To decrease the large gap between the post‐HCT vaccination guidelines and clinical practice, further studies on vaccine effectiveness and specific populations are warranted.
Whole‐genome DNA methylation patterns and complex associations with gene structure and expression during flower development in Arabidopsis
Authors: Yang Hongxing , Chang Fang , You Chenjiang , Cui Jie , Zhu Genfeng , Wang Lei , Zheng Yu , Qi Ji , Ma Hong
Published: November 2014

Flower development is a complex process requiring proper spatiotemporal expression of numerous genes. Accumulating evidence indicates that epigenetic mechanisms, including DNA methylation, play essential roles in modulating gene expression. However, few studies have examined the relationship between DNA methylation and floral gene expression on a genomic scale. Here we present detailed analyses of DNA methylomes at single‐base resolution for three Arabidopsis floral periods: meristems, early flowers and late flowers. We detected 1.5 million methylcytosines, and estimated the methylation levels for 24 035 genes. We found that many cytosine sites were methylated de novo from the meristem to the early flower stage, and many sites were demethylated from early to late flowers. A comparison of the transcriptome data of the same three periods revealed that the methylation and demethylation processes were correlated with expression changes of >3000 genes, many of which are important for normal flower development. We also found different methylation patterns for three sequence contexts (mCG, mCHG and mCHH) and in different genic regions, potentially with different roles in gene expression.
What is a Simple System?*
Authors: Paolo Beretta Gian , Gyftopoulos Elias P.
Published: November 2014

We discuss relations among properties of systems that consist of any amounts of constituents (including one particle), that have volume as the only parameter, and that are in thermodynamic equilibrium or stable equilibrium states. For large amounts of constituents, we introduce the concept of a simple system, and derive additional relations among properties.
Computational Fluid Dynamic Simulation of a Supercritical CO2 Compressor Performance Map
Authors: Rinaldi Enrico , Pecnik Rene , Colonna Piero
Published: November 2014

The performance map of a radial compressor operating with supercritical CO2 is computed by means of three-dimensional steady state Reynolds-averaged Navier–Stokes simulations. The geometry investigated is part of a 250 kW prototype which was tested at Sandia National Laboratories (SNL). An in-house fluid dynamic solver is coupled with a lookup table algorithm to evaluate the fluid properties. Tables are generated using a multiparameter equation of state, which ensures high accuracy in the fluid characterization. The compressor map is calculated considering three different rotational speeds (45 krpm, 50 krpm, and 55 krpm). For each speed-line, several mass flow rates are simulated. Numerical results are compared to experimental data from SNL to prove the potential of the methodology.
Breadth First Search Based COSINE Software Code Framework Automation Algorithm
Authors: Ren Hao , Mo Wentao , Zhao Guang , Ren Dangpei , Liu Shuo
Published: November 2014

Using software automation technology can significantly improve the quality and productivity of nuclear power software development. Based on the ‘tree’ data structure, this paper proposed Breadth First Search (BFS) based nuclear power software source code framework automatic generation algorithm called CFAA (Code Framework Automation Algorithm). CFAA uses ‘tree’ data structure to represent architecture of nuclear power software, then utilizes BFS to traverse all tree nodes to generate software source code framework. CFAA enables programmers to focus more on nuclear power software architecture design and optimization, and then generate the skeleton source code automatically. CFAA has been applied to COSINE (Core and System Integrated Engine for design and analysis) software development. Practice proved that CFAA can improve the efficiency of building nuclear power software framework, while reducing the defect rate of nuclear power software development.
Research on Precision Correcting for Heat Transfer Coefficient of Steam Turbine
Authors: Zhou Yan , Xie Danmei , Feng Yongxing , Liu Shi
Published: November 2014

As a high-speed rotating part, forced convection of the surface of rotor is high-intensity when steam turbine is running. The thermal state of the rotor directly affects the distribution of the stress and vibration characteristics. In order to effectively monitor and control the thermal state of the rotor, heat transfer coefficient must be quickly and accurately calculated. Typically, different manufacturers select different empirical formulas and the calculated values vary greatly. Combining with empirical formulas, the accuracy of steam turbine rotor surface heat transfer coefficient is improved, so that the results become closer to the numerical calculation values, then also result in analyzing the thermal state of rotor more precisely. Taking a certain 300MW turbine rotor as an application, the heat transfer coefficients of rotor are analyzed and calculated. And the improved method can be also applied in a 600MW steam turbine rotor.
Wet, Dry, and Hybrid Heat Rejection System Impacts on the Economic Performance of a Thermoelectric Power Plant Subjected to Varying Degrees of Water Constraint
Authors: Carter Thomas P. , Furlong James W. , Bushart Sean P. , Shi Jessica
Published: November 2014

The reduction of water consumption and use is emerging as a top priority for all types of thermoelectric power plants. In the United States, thermoelectric power production accounts for approximately 41% of freshwater withdrawals [1] and 3% of overall fresh water consumption. [2] On the basis of responses to a 2011 Electric Power Research Institute (EPRI) Request for Information [3], the feasibility study [4,5,6,7] of a Thermosyphon Cooler Hybrid System (TCHS) [8], proposed by Johnson Controls, was funded under EPRI’s Technology Innovation (TI) Water-Conservation Program. The objective of this project was to further develop the TCHS design concept for larger scale power plant applications and then perform a thorough technical and economic feasibility evaluation of the TSC Hybrid System and compare it to a variety of other competitive heat rejection systems.

The Thermosyphon Cooler Hybrid System reduces power plant cooling tower evaporative water loss by pre-cooling the condenser loop water through a dry cooling process employing an energy efficient, naturally recirculating refrigerant loop. This paper details the results of a detailed feasibility study that was conducted to compare the cost and performance of the TCHS to a number of other potential wet, dry, and hybrid thermoelectric power plant heat rejection systems operating under varying degrees of water constraint. Installed system cost estimates were developed for the base all wet cooling tower systems, TCHS’s of varying sizes, air-cooled condenser (ACC) hybrid systems of varying sizes, and all dry ACC systems.

Optimized all wet cooling tower and all dry ACC system configurations were developed for five different climatic locations. A comprehensive power plant simulation program that evaluated the fuel and water requirements of the power plants equipped with the different heat rejection systems across the weather conditions associated with all 8,760 hours of a typical meteorological year was developed and then an extensive array of simulations were run each location. The summary data were organized in a separate interactive dynamic system comparison summary program to allow users to gain further insight into the relationships between the various heat rejection systems and the sensitivity of the results to changes in key input assumptions.

This paper details the data presented in the interactive dynamic system comparison summary program. This program displays the key metrics of the Annual Net Cost of Power Production, the Annual Net Power Plant Profit, the Annual Operating Profit, and the Internal Rate of Return as a function of the Percent Annual Water Savings Required for the various heat rejection systems at each of the five studied climatic locations studied. Key results and conclusions are presented.
Xylene Addition Effects in Thermal Stage of Claus Reactors
Authors: Ibrahim Salisu , AlShoaibi Ahmed S. , Gupta Ashwani K.
Published: November 2014

Experimental results are presented on the effect of xylene addition to H2S/O2 flames at equivalence ratio of 3.0 (Claus Condition) with respect to H2S and complete combustion of xylene. The results from the combustion of H2S/xylene mixture is compared with the baseline case of 100% H2S combustion to isolate the role of xylene addition in the Claus reactor. Combustion of H2S alone showed a decrease in its mole until it reached to an asymptotic minimum mole fraction value. This resulted in the formation of SO2 to a maximum mole fraction which subsequently decomposed from the formation of elemental sulfur through its reaction with H2S. Addition of small amount of xylene (0.5% and 1%) increased the asymptotic minimum value of H2S as well as the formation of H2 which provided oxidation competition between the formed H2 and H2S. Presence of xylene also triggered the formation of CH4 and CO which provided pathway on the formation of COS and CS2. The oxidation of CH4 and CO by SO2 and other sulfur radicals reduced the maximum mole fraction of SO2 but increased the subsequent rate of SO2 decomposition to increase the formation rate of elemental sulfur. These results show the direct impact of trace amounts of xylene in the feed stream on sulfur formation to reveal direct impact on the Claus reactor performance for sulfur capture.
Green Heat: Hot Water Energy Offset System
Authors: Fowler Nathaniel , Wiand Jeff , Eddy Bryan , Lowery Andrew D. , Smith James E.
Published: November 2014

The implementation of renewable energy systems is often regarded by the consumer to be too costly and too complex to maintain and operate. For instance converting sunlight or wind energy to electricity along with the conditioning equipment required to put energy into the system can be cost prohibitive for a residential or commercial application. The proposed system implements multiple renewable energy components working in series. These components bypass those costly electrical energy conversions by converting the acquired energy into heat, which can be utilized to offset a portion of the energy consumed within the home or business. This system can be made completely transparent with little or no impact on the consumers’ lifestyle. Also, the proposed system, by only attempting to offset a portion of the current usage, will be simple and inexpensive to assemble and maintain with a short return on investment.

According to the U.S. Energy Information Administration an estimated 10 quadrillion Btu’s are consumed by 113.6 million houses in the United States, while 1.8 quadrillion Btu’s of the total energy is used for hot water heating [1]. It has been shown that approximately 20% of the energy costs associated with most residential and small commercial businesses stem from hot water heating. A patent-pending technology, called a viscous controller, attached at the base of a wind turbine, which operates in series with a traditional thermal solar collector to supplement the energy used in the hot water tank. This technology reduces the cost of the system and allows for the average homeowner and small business owner to offset their current energy usage, incorporate renewable energy sources, and offer a 4–5 year return on initial investment. More importantly, if this system is implemented in only a portion of the target market, it has the potential to completely offset the rising energy demands for the United States each year for the foreseeable future.
Performance Improvements of Nuclear Power Plants by the Application of Longer LP Last Stage Blades and Advanced Design Techniques
Authors: Jones Mike , Crossland Robert
Published: November 2014

Over the last decade, the Author’s company (Alstom Power) has retrofitted the steam turbines in 34 nuclear units on a diverse range of half and full-speed machines, powered by Pressurised and Boiling Water Reactors. Some of those projects have been described in other papers, with an explanation of the novel laser measurement and fast-track installation techniques that have been developed to meet the onerous demands of nuclear plants and authorities.

The ageing global nuclear fleet has suffered reduced levels of reliability and performance due to effects such as Stress Corrosion Cracking (SCC), moisture erosion and shaft line torsional faults. Alstom has developed a range of steam turbine retrofit solutions that are resistant to SCC and erosion, have extended maintenance intervals and deliver high levels of efficiency. A portfolio of rear stage blades is available, from which an optimum design can be selected to suit each project.

This paper focuses on the improvements in thermal performance and reliability of a number of recent nuclear steam turbine retrofits. It outlines the existing designs and some of the challenges faced by the plants concerning reliability, operation and efficiency and then describes the approach to addressing those issues by retrofitting with modern designs. The paper describes the blading design and the techniques which are used to evaluate exhaust performance. It will also show the methods which have been used to integrate longer Last Stage Blades into existing LP frames.

The paper concludes by presenting the experience, in terms of performance and installation, of some of the projects.
An Integrated Energy and Water Market for the Supply Side of the Energy-Water Nexus in the Engineered Infrastructure
Authors: Lubega William , Santhosh Apoorva , Farid Amro M. , Youcef-Toumi Kamal
Published: November 2014

In regions that utilize thermal desalination as part of their water supply portfolio, the cogeneration of water and power in cogeneration desalination plants couples the supply sides of the electricity and water grids. For a fixed plant design, there is a limited range of ratios of generated electric power to produced water at any given time. Due to this coupling, electricity and water require co-optimization. In an environment in which electricity supply is determined by deregulated wholesale markets, this need for co-optimization suggests a need for integrated electricity and water markets. In this market, independent power producers, independent water producers and independent cogeneration plants would submit bids to satisfy demand over a time horizon to a clearing mechanism, indicating relevant physical constraints. The mechanism would then optimize supply of both electricity and water over the time horizon of interest. Recently, a simultaneous co-optimization method has been contributed for the economic dispatch of networks that include water, power and cogeneration facilities in such an integrated market. This paper builds upon this foundation with the introduction of the corresponding unit commitment problem.
A Fuel Gas System Transient Study for Combined Cycle Plants
Authors: Yan Yizhou
Published: November 2014

Fuel gas for many Combined Cycle Power Plants is supplied directly by the gas provider’s regulator station in locations where the gas pipeline pressure is sufficient without further compression. Other locations require one or more onsite compressors to boost the fuel gas pressure. A rising concern is the fuel gas system transient response immediately after a significant reduction in the plant fuel gas consumption. Transient analysis models have been developed for typical fuel gas systems of combined cycle plants to ensure that the system is configured to respond appropriately to unplanned disturbances in fuel gas flow such as when a gas turbine trip occurs. Pressure control (regulator) and booster compressor control loop tuning parameters based on quantitative transient model results could be applied to set up targets for use in specifying and commissioning the fuel gas system. Case studies are presented for typical large combined cycle plants with two gas turbines taking fuel from a common plant header. This is done for designs without or with fuel gas booster compressors.
Role of Boiling Mode and Rate in Formation of Waterside Deposits in Heat Recovery Steam Generator Evaporator Tubes
Authors: Moelling David S. , Malloy James
Published: November 2014

Waterside Deposits in evaporator tubes have been an issue in steam generators as long as boilers have been used. Substantial experience in deposit formation and management has been gained in conventional goal and oil/gas boilers over time. The role of boiling modes in the steam generator tubes is very critical to areas of deposit formation. Incipient boiling, nucleate boiling and convective boiling modes all have different deposition behavior. When Gas Turbine Combined Cycle (GTCC) power plants of larger size (> 100 MW) began operation in the 1990’s, deposits in evaporator tubes were not considered a significant issue. Operating boiler pressures were low (500–900 psig) as were flue gas temperatures, use of supplemental firing was limited. Other than known problems with feedwater contamination such as operation with leaking seawater-cooled condensers, deposits were not found to be forming. The rapid increase in size and operating pressures in HRSG’s raised the likelihood of waterside deposits developing. Both Vertical and Horizontal Gas Path HRSG designs are considered. Drawing on field observations, the morphology and location of HRSG deposits are reviewed, as are changes in deposit formation with the mode and rate of boiling.
3-D Dynamic Simulation on Fluid-Structure Interaction of Air Flowing Around Prism
Authors: Wang Junlei , Ran JingYu , Ding Lin , Zhang Li
Published: November 2014

In this paper, a new method of generating power by “wind-induced vibration” (WIV). A lead zirconate titanate (PZT) beam which has a very high power density is installed on the bluff body which will have WIV with the bluff body has been explored. Both numerical computation and experimental work have been taken to measure the capacity of the power generating system. Two different shapes of bluff bodies have been tested. In numerical section, the lift and drag coefficient and the vortex shedding frequency have been computed to verify how the dimensionless parameter Vr affects the fluid field. An one-degree-freedom system has been added to describe the wind-induced vibration, and the vibrational frequency and amplitude of the vibration have been monitored. The fluid-structure interaction has been solved by a hybrid method of finite volume method (FVM) and finite element method (FEM). From numerical simulation, the conclusions can be given that as the non-dimensionalised mass m* is about 780, the vortex induced vibration (VIV) response of a single cylinder is quite different comparing with Govardhan&Williamson. Then a wind tunnel test has been taken to measure the voltage output of the PZT, and we have gotten a result quite close to the data of numerical method.
Turbulent Flow Energy Budget Calculations in a Dump Combustor Model
Authors: Ahmed Saad , Raghavan Bharath , Gadalla Mohamed
Published: November 2014

Turbulent statistics and energy budgets were calculated for a swirling turbulent flow using Generalized Feed Forward Neural Network (GFFNN) in a dump combustor model. Knowledge of turbulent statistics and energy budgets of fluid flow inside a combustor model is very useful and essential for better and/or optimum designs of gas turbine combustors. Several experimental techniques utilizing two dimensional (2D) or three dimensional (3D) Laser Doppler Velocimetry (LDV) measurements provide only limited discrete information at given points; especially, for the cases of complex flows such as dump combustor swirling flows. For these flows, numerical interpolating schemes are unsuitable. Recently, neural networks proved to be viable means of expanding a finite set of experimental measurements in order to enhance the understanding of complex phenomenon. This investigation showed that artificial neural networks are suitable for the prediction of turbulent swirling flow characteristics in a model dump combustor. These techniques are proposed for better designs and/or optimum performance of dump combustors.
Estimating Demand Response Potential of Buildings Using a Predictive HVAC Model
Authors: Sifuentes Froylan E. , Keep Taylor
Published: November 2014

Increasing penetration of intermittent renewable electricity into the grid, coupled with development of new communication and control strategies, is creating challenges and opportunities for demand response (DR) to balance the grid. This paper presents a model characterization of a controllable buildings Variable Air Volume HVAC (VAV HVAC) system capable of implementing control strategies that provide flexibility to the grid. A Model Predictive Controller (MPC) capable of reliably varying the modeled power by ±20%, or up to ±2 GW on a national scale, every five minutes without compromising occupants comfort was built. A climate analysis was performed in order to assess the availability of controllable resources in sixteen cities. It is found that this control strategy could be implemented up to 99% of the time in the hottest regions, but as low as 10% of the time in the coldest.
Effects of Axis Ratio on the Vortex-Induced Vibration and Energy Harvesting of Rhombus Cylinder
Authors: Zhang Li , Li Heng , Ding Lin
Published: November 2014

The vortex-induced vibrations of a rhombus cylinder are investigated using two-dimensional unsteady Reynolds-Averaged Navier-Stokes simulations at high Reynolds numbers ranging from 10,000 to 120,000. The rhombus cylinder is constrained to oscillate in the transverse direction, which is perpendicular to the flow velocity direction. Three rhombus cylinders with different axis ratio (AR=0.5, 1.0, 1.5) are considered for comparison. The simulation results indicate that the vibration response and the wake modes are dependent on the axis ratio of the rhombus cylinder. The amplitude ratios are functions of the Reynolds numbers. And as the AR increases, higher peak amplitudes can be made over a significant wide band of Re. On the other hand, a narrow lock-in area is observed for AR=0.5 and AR=1.5 when 30,000<Re<50,000, but the frequency ratio of AR=1.0 monotonically increases at a nearly constant slope in the whole Re range. The vortex shedding mode is always 2S mode in the whole Re range for AR=0.5. However, the wake patterns become diverse with the increasing of Re for AR=1.0 and 1.5. In addition, the mechanical power output of each oscillating rhombus cylinder is calculated to evaluate the efficiency of energy transfer in this paper. The theoretical mechanical power P between water and a transversely oscillating cylinder is achieved. On the base of analysis and comparison, the rhombus cylinder with AR=1.0 is more suitable for harvesting energy from fluid.
CFD Simulations of Flow and Heat Transfer Through the Porous Interface of a Metal Foam Heat Exchanger
Authors: Sauret Emilie , Hooman Kamel , Saha Suvash C.
Published: November 2014

This paper offers numerical modelling of a waste heat recovery system. A thin layer of metal foam is attached to a cold plate to absorb heat from hot gases leaving the system. The heat transferred from the exhaust gas is then transferred to a cold liquid flowing in a secondary loop. Two different foam PPI (Pores Per Inch) values are examined over a range of fluid velocities. Numerical results are then compared to both experimental data and theoretical results available in the literature. Challenges in getting the simulation results to match those of the experiments are addressed and discussed in detail. In particular, interface boundary conditions specified between a porous layer and a fluid layer are investigated. While physically one expects much lower fluid velocity in the pores compared to that of free flow, capturing this sharp gradient at the interface can add to the difficulties of numerical simulation. The existing models in the literature are modified by considering the pressure gradient inside and outside the foam. Comparisons against the numerical modelling are presented. Finally, based on experimentally-validated numerical results, thermo-hydraulic performance of foam heat exchangers as waste heat recovery units is discussed with the main goal of reducing the excess pressure drop and maximising the amount of heat that can be recovered from the hot gas stream.
Numerical Study of a Multipurpose Power Generator Using the Finite Element Method
Authors: Agbormbai J. , Goudarzi N. , Zhu W. D.
Published: November 2014

Analytical and experimental analyses of a variable electromotive-force generator (VEG) show the advantages of this modified generator in hybrid electric vehicle and wind turbine applications with enhancing the fuel efficiency and expanding the operational range, respectively. In this study, electromagnetic analysis of a modified two-pole DC generator with an adjustable overlap between the rotor and the stator is studied using 3-D finite element simulation in ANSYS. The generator stator is modeled with two opposite pole pieces whose arcs span between 15° to 90° in the counterclockwise direction and −15° to −90° in the clockwise direction. A semicircular cylinder whose arc spans between −90° and 90° is used to model the generator rotor. A tetrahedral mesh is used to provide a solution for changes in the electromotive force at different frequencies and overlap ratios. For a constant electromagnetic flux density and fixed number of coils, the changes in the electromotive force at different overlap ratios between the rotor and the stator are obtained in static conditions. There is a very good correlation between the results from simulation and those from analytical and experimental studies.