bluuebunny/crossref_metadata_2025 huggingface dataset:
Earthworms in Soil Restoration: Lessons Learned from United Kingdom Case Studies of Land Reclamation
Authors: Butt Kevin R
Published: November 2008

Restoration ecology requires theoretical consideration of a habitat’s former structure and function before the practice of ecological restoration is applied. However, experience has shown that this does not always occur and aspects such as soil ecology have often been an afterthought. Here, case study material relates the use of earthworms at selected sites in the United Kingdom. Due to their soil‐forming capabilities, these organisms may be essential to reconstruction of soils when drastic activities have despoiled an area. While describing in brief the type of work undertaken, these case studies seek to illustrate some of the misunderstandings/problems/deliberately negative acts that have too often accompanied use of earthworms in soil restoration. From such experiences, implications for practice are suggested that should lead to a greater understanding and appropriate utilization of earthworms in future projects.
Current and Potential Roles of Soil Macroinvertebrates (Earthworms, Millipedes, and Isopods) in Ecological Restoration
Authors: Snyder Bruce A. , Hendrix Paul F.
Published: November 2008

Soil macroinvertebrates have a considerable impact on soil functions important to the restoration process, such as decomposition; yet, soil organisms have received relatively little attention in restoration ecology in terms of their applicability as agents of restoration. Here, we review how large obligate detritivores (earthworms, millipedes, and isopods) have been used to accomplish restoration goals, assess restoration progress, and function as bioindicators. Patterns of detritivore community succession and how these communities are themselves restored during restoration of perturbed ecosystems are also discussed. We conclude with a discussion of increased utilization of these taxa in future and ongoing restoration projects as well as the outreach activities that should be associated with use of these organisms.
The Nature of Urban Soils and Their Role in Ecological Restoration in Cities
Authors: Pavao‐Zuckerman Mitchell A.
Published: November 2008

Current and predicted trends indicate that an increasing proportion of the world’s population is living in urban and suburban places. The nature of the urban environment becomes an important factor if we are concerned with the restoration and preservation of biodiversity and ecosystems in and around cities. This article highlights the varied impacts of cities on soils and their implications for restoration planning and expectations of restoration “success.” Urban soils exist in different historical and formational trajectories than their local nonurbanized counterparts due to direct anthropogenic disturbance and indirect environmental impacts from urbanization. Therefore, urban soils often exhibit altered physical, chemical, and biological characteristics in comparison to local nonurbanized soils. Several unique features of urban soils and urban ecosystems pose particular issues for ecological restoration or the improvement of degraded soil conditions in cities. The creation of novel soil types, conditions that promote invasion by non‐natives, the strong influence of past land use on soil properties, and the presence of strong interactions and alternative stable states set up unique difficulties for the restoration of urban soils. Soils in urban restorations are a medium that can be deliberately manipulated to improve site conditions or in the monitoring of soil conditions as indices of ecosystem status. Including an explicit role for strong manipulations of soils in urban ecosystems changes how we approach baselines, management, and reference conditions in urban ecological restoration. With an understanding of urban soil ecological knowledge, we can guide aspects of urban ecological restoration toward successful outcomes.
A Striking Profile: Soil Ecological Knowledge in Restoration Management and Science
Authors: Callaham Mac A. , Rhoades Charles C. , Heneghan Liam
Published: November 2008

Available evidence suggests that research in terrestrial restoration ecology has been dominated by the engineering and botanical sciences. Because restoration science is a relatively young discipline in ecology, the theoretical framework for this discipline is under development and new theoretical offerings appear regularly in the literature. In reviewing this literature, we observed an absence of in‐depth discussion of how soils, and in particular the ecology of soils, can be integrated into the developing theory of restoration science. These observations prompted us to assess the current role of soil ecological knowledge in restoration research and restoration practice. Although soils are universally regarded as critical to restoration success, and much research has included manipulations of soil variables, we found that better integration of soil ecological principles could still contribute much to the practice of ecosystem restoration. Here we offer four potential points of departure for increased dialog between restoration ecologists and soil ecologists. We hope to encourage the view that soil is a complex, heterogeneous, and vital entity and that adoption of this point of view can positively affect restoration efforts worldwide.
Hyper IgE (Job’s) syndrome: a primary immune deficiency with oral manifestations
Authors: Freeman AF , Domingo DL , Holland SM
Published: November 2008

Autosomal dominant hyper IgE (HIES or Job’s) syndrome is a rare primary immune deficiency characterized by eczema, recurrent skin and lung infections, extremely elevated serum IgE, and a variety of connective tissue and skeletal abnormalities. Individuals with HIES share a characteristic facial appearance and many oral manifestations including retained primary dentition, a high arched palate, variations of the oral mucosa and gingiva, and recurrent oral candidiasis. Mutations in STAT3 account for the majority, if not all, of the cases of autosomal dominant HIES, but the pathogenesis of the many varied features remains poorly understood. In this review, we discuss the clinical phenotype of HIES including immunologic and non‐immunologic features, the genetics of HIES, and treatment.
Effects of Irrigation and Nitrogen on the Performance of Aerobic Rice in Northern China
Authors: Xue Chang‐Ying , Yang Xiao‐Guang , Bouman B.A.M. , Deng Wei , Zhang Qiu‐Ping , Yang Jie , Yan Wei‐Xiong , Zhang Tian‐Yi , Rouzi A‐Ji , Wang Hua‐Qi , Wang Pu
Published: November 2008

Aerobic rice is a new production system in which specially‐developed varieties are grown under non‐flooded, non‐puddled, and non‐saturated soil conditions. In 2003–2004, irrigation x Nitrogen experiments were carried out near Beijing using variety HD297. Water treatments included four irrigation levels, and Nitrogen treatments included different fertilizer N application rates and different numbers of N splits. The highest yields were 4 460 kg/ha with 688 mm of total (rain plus irrigation) water input in 2003 and 6 026 kg/ha with 705 mm of water input in 2004. Because of the quite even distribution of rainfall in both years, the four irrigation treatments did not result in large differences of soil water conditions. There were few significant effects of irrigation on biomass accumulation, but yield increased with the total amount of water applied. High yields coincided with high harvest index and high percentages of grain filling. The application of fertilizer N either reduced biomass and yield or kept it at the same level as 0 N and consistently reduced the percentage grain filling and 1 000‐grain weight. With the highest water application, five splits of N gave higher yield than three splits, whereas three splits gave higher yield than five splits with lower water applications.
PRELIMINARY STUDIES ON PHYSICAL AND NUTRITIONAL QUALITIES OF SOME INDIGENOUS AND IMPORTANT RICE CULTIVARS OF NORTH‐EASTERN HILL REGION OF INDIA
Authors: DEVI TH. PREMILA , DURAI A. ANNA , SINGH TH. ANAND , GUPTA S. , MITRA J. , PATTANAYAK A. , SARMA B.K. , DAS A.
Published: November 2008

The northeastern hills of India are endowed with rich source of rice germplasm, which may be safely estimated about 9,000 accessions, excluding the redundancies. Even though much of the germplasm have been collected, studies on nutritional aspects of these local cultivars are still lacking. Fifteen important indigenous rice genotypes collected from different rice growing ecosystem of this region were studied for physical and nutritional qualities. Kernel color of the genotypes varied from white to dark purple. All the genotypes except Manipuri were of bold‐grain type. Most of the genotypes studied have fat contents more than 2.0%. The protein content was found higher in Chahou angouba and Naga special. Five cultivars were identified as high‐protein cultivars of rice, with 10–12.07% protein content. Amylose content varied from 2.27 to 24.5%. Most of long‐grained genotypes recorded lesser amylose than short grained. Chahou varieties were found aromatic and glutinous, which demand higher market prices in local market.

PRACTICAL APPLICATION

The north‐eastern hills of India are endowed with rich source of rice germplasm, and much of the germplasm have been collected, but studies on basic and advanced nutritional aspects of these local cultivars are still lacking. This part of India has valuable rice genotypes of strong aroma, glutinous characters and slender grains with high amount of protein, fat and fiber. Having not known to the rest of the world and even to indigenous end users, some of such cultivars have already been lost, and some more are at the verge of extinction. Quality evaluation done in the present study provided useful information on their commercial exploitation and utilization in breeding programs of nutritional enhancement of rice to fight malnutrition among rice‐consuming population, which is largest in the world.
PAIRED PREFERENCE TESTS: “50:50” AND “ALTERNATING” NO PREFERENCES
Authors: ALFARO‐RODRÍGUEZ HAYDE , ANGULO OFELIA , O'MAHONY MICHAEL
Published: November 2008

Because the concept of “No Preference” is ambiguous, two types of “No Preference” are defined: a “50:50” No Preference, defined operationally as consumers presented with both products having a 50% chance of choosing either, and an “Alternating” No Preference, where the probability is not 50%. The consumer would be more likely to choose one of the products. However, later, he or she might choose the other product. To investigate this, paired preference tests were performed with and without the “No Preference” option for various products. No discernible trend was noted for consumers who had chosen the “No Preference” option and distributed their votes among the preference options. These consumers and those who changed their preferences were classified according to the “50:50” No Preference and “Alternating” No Preference dichotomy accordingly.

PRACTICAL APPLICATIONS

Besides the tendency of consumers to report false preferences, paired preference tests have another problem: the concept of “No Preference” is ambiguous. It could mean that consumers liked both products equally and so would always have a 50% chance of choosing either. It could also mean that the probability is not 50% on any one occasion but varies so that one product is chosen on one occasion and the other product on another occasion. To avoid confusing the consumer so as to obtain more valid data, it is important to specify these two meanings of “No Preference.” This study is a first step in that direction and should help consumers understand better the instructions for preference tests.
Scanning electron microscopy evaluation of the hard tissue barrier after pulp capping with calcium hydroxide, mineral trioxide aggregate (MTA) or ProRoot MTA
Authors: Reston Eduardo Galia , De Souza Costa Carlos Alberto
Published: November 2008

The aim of this study was to investigate the morphology and localisation of calcium hydroxide‐ and mineral trioxide aggregate (MTA)‐induced hard tissue barriers after pulpotomy in dogs' teeth. Pulpotomies were performed on maxillary and mandibular premolars of five dogs. The teeth were assigned into three groups according to the pulp‐capping agent used. The pulpal wounds were capped with calcium hydroxide (Ca(OH)2– control), MTA or ProRoot MTA, and the cavities were restored with amalgam. After a 90‐day follow‐up period, the dogs were euthanised and the teeth were examined under scanning electron microscopy (SEM). An image‐processing and analysis software was used to delimit the perimeters of the root canal area and the hard tissue barrier to determine the percentage of root canal obliteration. SEM data were used to assess the morphology, localisation and extension of the reparative hard tissue barriers. ProRoot MTA was statistically different from MTA and Ca(OH)2 (P < 0.05) regarding tissue barrier morphology. Localisation data showed that ProRoot MTA was significantly different from Ca(OH)2 (P < 0.05) and similar to MTA (P > 0.01; P > 0.05). No statistically significant difference (P > 0.01; P > 0.05) was observed between MTA and Ca(OH)2. A larger number of complete (centroperipheral) hard tissue barriers with predominance of dentinal tubules was observed to the ProRoot MTA when compared with the Ca(OH)2 group.
Effect of two storage solutions on surface topography of two root‐end fillings
Authors: Asgary Saeed , Eghbal Mohammad Jafar , Parirokh Masoud , Ghoddusi Jamileh
Published: November 2008

The effect of different storage solutions on surface topography of mineral trioxide aggregate (MTA) and new experimental cement (NEC) as root‐end fillings was investigated. Twenty‐four single‐rooted teeth were cleaned, shaped and obturated in a same manner. After root‐end resection, 3‐mm deep root‐end cavities were ultrasonically prepared. Samples were randomly divided into four test groups (A1‐A2‐B1‐B2, n = 6). Root‐end cavities in groups A and B were filled with MTA and NEC, respectively, and were then stored in 100% humidity for 24 h. The samples of groups 1 and 2 were, respectively, immersed in normal saline (NS) and phosphate buffer saline solutions for 1 week. The samples were imaged under stereomicroscope before and after immersion and were then investigated and analysed by scanning electron microscopy (SEM) and energy dispersive X‐ray analysis (EDXA). Results showed significant difference among studied groups. Surface topography of all samples was altered by crystal formation and precipitation on root‐end fillings except for group A1 (MTA–NS). SEM and EDXA results showed that the composition and structure of precipitated crystals were comparable with that of standard hydroxyapatite. It was concluded that biocompatibility, sealing ability, and cementogenic activity of MTA and probably NEC may be attributed to this fundamental bioactive reaction.
Incidence rate of musculoskeletal injuries and determinants of time to recovery in young Australian Thoroughbred racehorses
Authors: Cogger N , Evans DL , Hodgson DR , Reid SW , Perkins N
Published: November 2008

Objective  To describe the incidence rate of musculoskeletal (MS) injuries and investigate the factors that influence recovery from MS injury in young Thoroughbred horses in Australia.

Methods  Training and injury data were collected at fortnightly intervals from 14 trainers in New South Wales. Incidence rates were calculated for initial injuries stratified by age‐class and sex. Survival analysis methods were used to investigate the time to recovery after the first MS injury (measured as a start in a race or barrier trial).

Results  For the 248 racehorses enrolled, there were 428 injuries recorded; 2‐year‐olds were 2.99‐fold more likely than 3‐year‐olds to sustain an MS injury. The cumulative percentage of horses that had recovered within 6 months was 55%. The time to recovery was longest in horses whose fast gallop speed prior to injury was < 890 m/min.

Conclusion  This study supports the finding that shin soreness is the most common MS injury in young Australian Thoroughbreds. There was an increased rate of MS injury in 2‐year‐olds compared with 3‐year‐olds. However, it was impossible to determine if the increased risk in 2‐year‐olds was related to age, the start of training or a combination of both. The study also found that horses performing at higher exercise speeds prior to injury were more likely to recover. There was a significant effect of trainer, suggesting that other factors related to trainer may influence the time to the recovery. Additional research is required to understand the determinants of time to recovery.
Hepatitis C virus F protein inhibits cell apoptosis by activation of intracellular NF‐κB pathway
Authors: Shao Sheng‐wen , Wu Wen‐bin , Bian Zhong‐qi , Yu Jian‐guo , Zhao Ping , Zhao Lan‐juan , Zhu Shi‐ying , Qi Zhong‐tian
Published: November 2008

Aim:  To observe the influence of HCV F protein on apoptosis of HepG2 cells, and explore the association between F protein and NF‐κB signal pathway.

Methods:  HCV 1b F gene containing HepG2‐F cells and HCV 1b C gene containing HepG2‐C cells were treated with 100 IU/mL TNF‐α, and analyzed by flow cytometry, Western blotting, and dual luciferase reporter assay. Empty plasmid pcDNA3.1+ containing HepG2‐3.1 cells were used as control.

Results:  (i) With the treatment of TNF‐α for 18 h, the apoptosis rates (AR) of HepG2‐F and HepG2‐3.1 cells were 0.41% (± 0.11%) and 37.43% (± 2.03%) respectively, while that of HepG2‐C was 4.07% (± 0.18%). At 36 h after TNF‐α treatment, the AR of HepG2‐F and HepG2‐3.1 cells were 10.03% (± 0.41%) and 44.63% (± 3.37%), and that of HepG2‐C was 14.95% (± 0.85%). (ii) After the treatment of TNF‐α for 0.5–18 h, the p65 contents in the whole cells of HepG2‐F and HepG2‐3.1 showed no significant difference (P = 0.34, t = 1.08), while the p65 contents in the nucleus of HepG2‐F and HepG2‐3.1 cells were 3.8–1.9 times and 1.8–1.0 times higher than that in the non‐treated cells (P = 0.013, t = 4.25). (iii) The relative luciferase unit (RLU) of the HepG2 cells, co‐transfected with pcDNA3.1‐F and pNF‐κB‐luc, and then treated with TNF‐α (100 IU/mL) for 18 h, showed a pcDNA3.1‐F dose‐dependent increase.

Conclusion:  HCV F protein can over‐activate NF‐κB signal pathway, which makes HepG2‐F cells able to resist TNF‐α induced apoptosis.
Significance of dihydropyrimidine dehydrogenase and thymidylate synthase mRNA expressions in hepatocellular carcinoma
Authors: Nii Akira , Shimada Mitsuo , Ikegami Toru , Harino Yukari , Imura Satoru , Morine Yuji , Kanemura Hirofumi , Arakawa Yusuke , Sugimoto Koji
Published: November 2008

Aim:  The significance of dihydropyrimidine dehydrogenase (DPD) and thymidylate synthase (TS) gene expressions for the post‐surgical prognosis of hepatocellular carcinoma (HCC) has not yet been determined. In the present study, we clarified the significance of DPD and TS gene expressions for the prognosis of HCC.

Methods:  Seventy‐four patients, who underwent curative hepatic resection for primary HCC, were evaluated. The DPD and TS mRNA levels of the resected HCC specimens were evaluated using a microdissection technique and quantative real‐time RT‐PCR. The patients were categorized into high and low groups for each mRNA based on the median value. Various clinicopathological factors, including prognosis, and proliferation index using Ki‐67 staining were evaluated in association with the DPD and TS mRNA expression levels.

Results:  The low DPD mRNA expression was related to younger age, advanced clinical stage, undifferentiated histology, and microscopic intrahepatic metastasis. The overall and recurrence‐free survival were significantly lower in the low DPD group than in the high DPD group (P < 0.05). Furthermore, the proliferation index in the low DPD group was significantly higher than that in the high DPD group (P < 0.01). On the other hand, the high TS group showed a tendency of better prognosis than the low TS group, although it was not statistically significant.

Conclusions:  The low DPD mRNA expression is a significant poor prognostic factor. after curative resection of HCC.
Positioning the New Reggaetón Stars in Cuba: From Home‐Based Recording Studios to Alternative Narratives
Authors: Boudreault‐Fournier Alexandrine
Published: November 2008

A principios de los años 2000, el reggaetón, un fenómeno musical caribeño asociado a valores individualistas y mercantilistas, llegó a las costas cubanas. Este artículo defiende la relevancia de hegemonía, ideología y articulación en la localización de las prácticas y narrativas de los productores de música reggaetón (reggaetoneros) dentro de la sociedad cubana contemporánea. Los reggaetoneros participan en redes paralelas, que les permiten comercializar, promover y distribuir su música fuera de las regulaciones del estado Asimismo, los reggaetoneros se mantienen fieles a una retórica nacionalista marginal pero no dirigida contra las narrativas dominantes. La expresión de varias ideologías alternativas por parte de los reggaetoneros y su implicación en las redes paralelas ilustran como fluctúan entre su proximidad al proyecto revolucionario algunas veces y su alejamiento del mismo en otras ocasiones.

In the early 2000s, reggaetón, a Caribbean music phenomenon associated with individualist and market‐oriented values, disembarked on Cuban shores. This article defends hegemony, ideology, and articulation as concepts relevant to the act of situating the practices and narratives of reggaetón producers (reggaetoneros) within contemporary Cuban society. Reggaetoneros are actively involved in parallel networks, which allow them to commercialize, promote, and distribute their music outside of state regulations. Similarly, reggaetoneros adhere to a nationalist rhetoric that is on the margins but not directed against the dominant narratives. The articulation of various alternative ideologies by reggaetoneros and their involvement in parallel networks illustrate how they oscillate between being close to the revolutionary project at times, and distant from it at others.
Lia Won't: Agency in the Retrospective Pregnancy Narratives of Low‐Income Brazilian Women
Authors: O'Dougherty Maureen
Published: November 2008

O rápido declínio das taxas de fecundidade no Brasil, de uma média de 6 bebês nascidos vivos por mulher em 1965 a 2,5 em 1996, occorreu num contexto no qual o aborto induzido é ilegal e a esterilização não foi autorizada pelo Código de Ética Médica antes de 1997. No entanto, mais de um quarto de brasileiras, unidas e solteiras, escolhem a esterilização até os 30 anos de idade. Esta pesquisa analisa narrativas de gravidez de 30 brasileiras de baixa renda, com 25 a 50 anos de idade, com a finalidade de entender como elas representam sua própria atuação (agency) e a atuação de outros, em relação a decisões sobre a gravidez. O protocolo de análise de agência (agency), tal como ela é representada nas narrativas, comprende três categorias analíticas: a agência do outro, em gravidezes não planejadas; a agência recuperadora–quando a mulher reassume o controle por meio do aborto induzido ou da aceitação da maternidade; e a agência antecipada, no qual a sua decisão incide sobre o futuro, por meio da esterilização.

Brazil's rapid fertility decline, from six births per woman in 1965 to 2.5 in 1996, occurred in a context where abortion is illegal and sterilization sanctioned (until 1997) by the medical code of ethics. Still, more than one‐quarter of Brazilian women, both single and in stable union, choose sterilization by age 30. This research analyzed 30 pregnancy narratives of low‐income Brazilian women aged 25–50 to understand how they represent their agency, and the agency of others, in relation to pregnancy decisions. Three analytical categories comprise my method for examination of agency as represented in narrative: proximal (the agency of others) in unintended pregnancy; recuperative agency—reassuming control with abortion or embracing motherhood; and pre‐emptive or forward‐acting agency, through sterilization.
Aeroelastic Analysis of Rotors With Flexible Disks and Alternate Blade Mistuning
Authors: Bleeg James M. , Yang Ming-Ta , Eley James A.
Published: November 2008

A new reduced-order aeroelastic model using the principal shapes (AMPSs) of modes is presented. Rotors with flexible disks and alternate blade mistuning can challenge the fidelity of flutter prediction techniques that assume uniform blade-to-blade geometry and mode shape invariance with nodal diameter pattern. The AMPS method, however, accounts for alternating blade geometry as well as varying blade mode shapes, providing accurate flutter predictions for a large number of modes from a small number of computational fluid dynamics simulations. AMPS calculations on rotors with alternate blade mistuning are presented and compared to other prediction techniques. The results provide insight into how alternate blade mistuning affects aerodynamic coupling and the flutter characteristics of a rotor.
Turbine Airfoil Net Heat Flux Reduction With Cylindrical Holes Embedded in a Transverse Trench
Authors: Harrison Katharine L. , Dorrington John R. , Dees Jason E. , Bogard David G. , Bunker Ronald S.
Published: November 2008

Film cooling adiabatic effectiveness and heat transfer coefficients for cylindrical holes embedded in a 1d transverse trench on the suction side of a simulated turbine vane were investigated to determine the net heat flux reduction. For reference, measurements were also conducted with standard inclined, cylindrical holes. Heat transfer coefficients were determined with and without upstream heating to isolate the hydrodynamic effects of the trench and to investigate the effects of the thermal approach boundary layer. Also, the effects of a tripped versus an untripped boundary layer were explored. For both the cylindrical holes and the trench, heat transfer augmentation was much greater for the untripped approach flow. A further increase in heat transfer augmentation was caused by use of upstream heating, with as much as a 180% augmentation for the trench. The tripped approach flow led to much lower heat transfer augmentation than the untipped case. The net heat flux reduction for the trench was found to be significantly higher than for the row of cylindrical holes.
Effect of End Wall Contouring on Performance of Ultra-Low Aspect Ratio Transonic Turbine Inlet Guide Vanes
Authors: Sonoda Toyotaka , Hasenjäger Martina , Arima Toshiyuki , Sendhoff Bernhard
Published: November 2008

In our previous work on ultralow-aspect ratio transonic turbine inlet guide vanes (IGVs) for a small turbofan engine (Hasenjäger et al., 2005, “Three Dimensional Aerodynamic Optimization for an Ultra-Low Aspect Ratio Transonic Turbine Stator Blade,” ASME Paper No. GT2005-68680), we used numerical stochastic design optimization to propose the new design concept of an extremely aft-loaded airfoil to improve the difficult-to-control aerodynamic loss. At the same time, it is well known that end wall contouring is an effective method for reducing the secondary flow loss. In the literature, both “axisymmetric” and “nonaxisymmetric” end wall geometries have been suggested. Almost all of these geometric variations have been based on the expertise of the turbine designer. In our current work, we employed a stochastic optimization method—the evolution strategy—to optimize and analyze the effect of the axisymmetric end wall contouring on the IGV’s performance. In the optimization, the design of the end wall contour was divided into three different approaches: (1) only hub contour, (2) only tip contour, and (3) hub and tip contour, together with the possibility to observe the correlation between hub/tip changes with regard to their joint influence on the pressure loss. Furthermore, three-dimensional flow mechanisms, related to a secondary flow near the end wall region in the low-aspect ratio transonic turbine IGV, was investigated, based on the above optimization results. A design concept and secondary flow characteristics for the low-aspect ratio full annular transonic turbine IGV is discussed in this paper.
Film Cooling Measurements for Cratered Cylindrical Inclined Holes
Authors: Lu Yiping , Dhungel Alok , Ekkad Srinath V. , Bunker Ronald S.
Published: November 2008

Film cooling performance is studied for cylindrical holes embedded in craters. Different crater geometries are considered for a typical crater depth. Cratered holes may occur when blades are coated with thermal barrier coating layers by masking the hole area during thermal barrier coating (TBC) spraying, resulting in a hole surrounded by a TBC layer. The film performance and behavior is expected to be different for the cratered holes compared to standard cylindrical holes. Detailed heat transfer coefficient and film effectiveness measurements are obtained simultaneously using a single test transient IR thermography technique. The study is performed at a single mainstream Reynolds number based on freestream velocity and film-hole diameter of 11,000 at four different coolant-to-mainstream blowing ratios of 0.5, 1.0, 1.5, and 2.0. The results show that film cooling effectiveness is slightly enhanced by cratering of holes, but a substantial increase in heat transfer enhancement negates the benefits of higher film effectiveness. Three different crater geometries are studied and compared to a base line flush cylindrical hole, a trenched hole, and a typical diffuser shaped hole. Computational fluid dynamics simulation using FLUENT was also performed to determine the jet-mainstream interactions associated with the experimental surface measurements.
Effect of Trench Width and Depth on Film Cooling From Cylindrical Holes Embedded in Trenches
Authors: Lu Yiping , Dhungel Alok , Ekkad Srinath V. , Bunker Ronald S.
Published: November 2008

The present study is an experimental investigation of film cooling from cylindrical holes embedded in transverse trenches. Different trench depths are considered with two trench widths. Trench holes can occur when blades are coated with thermal barrier coating (TBC) layers. The film-hole performance and behavior will be different for the trench holes compared to standard cylindrical holes that are flush with the surface. The trench width and depth depend on the mask region and the thickness of the TBC layer. Detailed heat transfer coefficient and film effectiveness measurements are obtained simultaneously using a single test transient IR thermography technique. The study is performed at a single mainstream Reynolds number based on freestream velocity and film-hole diameter of 11,000 at four different coolant-to-mainstream blowing ratios of 0.5, 1.0, 1.5, and 2.0. The results show that film effectiveness is greatly enhanced by the trenching due to the improved two-dimensional nature of the film and lateral spreading. The detailed heat transfer coefficient and film effectiveness contours provide a clear understanding of the jet-mainstream interactions for different hole orientations. Computational fluid dynamics simulation using FLUENT was also performed to determine the jet-mainstream interactions to better understand the surface heat transfer coefficient and film effectiveness distributions.
Experimental and Numerical Impingement Heat Transfer in an Airfoil Leading-Edge Cooling Channel With Cross-Flow
Authors: Taslim M. E. , Bethka D.
Published: November 2008

To enhance the internal heat transfer around the airfoil leading-edge area, a combination of rib-roughened cooling channels, film cooling, and impingement cooling is often employed. Experimental data for impingement on various leading-edge geometries are reported by these and other investigators. The effects of strong cross-flows on the leading—edge impingement heat transfer, however, have not been studied to that extent. This investigation dealt with impingement on the leading edge of an airfoil in the presence of cross-flows beyond the cross-flow created by the upstream jets (spent air). Measurements of heat transfer coefficients on the airfoil nose area as well as the pressure and suction side areas are reported. The tests were run for a range of axial to jet mass flow rates (Maxial∕Mjet) ranging from 1.14 to 6.4 and jet Reynolds numbers ranging from 8000 to 48,000. Comparisons are also made between the experimental results of impingement with and without the presence of cross-flow and between representative numerical and measured heat transfer results. It was concluded that (a) the presence of the external cross-flow reduces the impinging jet effectiveness both on the nose and sidewalls; (b) even for an axial to jet mass flow ratio as high as 5, the convective heat transfer coefficient produced by the axial channel flow was less than that of the impinging jet without the presence of the external cross-flow; and (c) the agreement between the numerical and experimental results was reasonable with an average difference ranging from −8% to −20%.
Aerothermal Investigations of Tip Leakage Flow in Axial Flow Turbines—Part I: Effect of Tip Geometry and Tip Clearance Gap
Authors: Krishnababu S. K. , Newton P. J. , Dawes W. N. , Lock G. D. , Hodson H. P. , Hannis J. , Whitney C.
Published: November 2008

A numerical study has been performed to investigate the effect of tip geometry on the tip leakage flow and heat transfer characteristics in unshrouded axial flow turbines. Base line flat tip geometry and squealer type geometries, namely, double squealer or cavity and suction-side squealer, were considered. The performances of the squealer geometries, in terms of the leakage mass flow and heat transfer to the tip, were compared with the flat tip at two different tip clearance gaps. The computations were performed using a single blade with periodic boundary conditions imposed along the boundaries in the pitchwise direction. Turbulence was modeled using three different models, namely, standard k-ε, low Re k-ω, and shear stress transport (SST) k-ω, in order to assess the capability of the models in correctly predicting the blade heat transfer. The heat transfer and static pressure distributions obtained using the SST k-ω model were found to be in close agreement with the experimental data. It was observed that compared to the other two geometries considered, the cavity tip is advantageous both from the aerodynamic and from the heat transfer perspectives by providing a decrease in the amount of leakage, and hence losses, and average heat transfer to the tip. In general, for a given geometry, the leakage mass flow and the heat transfer to the tip increased with increase in tip clearance gap. Part II of this paper examines the effect of relative casing motion on the flow and heat transfer characteristics of tip leakage flow. In Part III of this paper the effect of coolant injection on the flow and heat transfer characteristics of tip leakage flow is presented.
Endwall Boundary Layer Development in an Engine Representative Four-Stage Low Pressure Turbine Rig
Authors: Vera Maria , de la Rosa Blanco Elena , Hodson Howard , Vazquez Raul
Published: November 2008

Research by de la Rosa Blanco et al. (“Influence of the State of the Inlet Endwall Boundary Layer on the Interaction Between the Pressure Surface Separation and the Endwall Flows,” Proc. Inst. Mech. Eng., Part A, 217, pp. 433–441) in a linear cascade of low pressure turbine (LPT) blades has shown that the position and strength of the vortices forming the endwall flows depend on the state of the inlet endwall boundary layer, i.e., whether it is laminar or turbulent. This determines, amongst other effects, the location where the inlet boundary layer rolls up into a passage vortex, the amount of fluid that is entrained into the passage vortex, and the interaction of the vortex with the pressure side separation bubble. As a consequence, the mass-averaged stagnation pressure loss and therefore the design of a LPT depend on the state of the inlet endwall boundary layer. Unfortunately, the state of the boundary layer along the hub and casing under realistic engine conditions is not known. The results presented in this paper are taken from hot-film measurements performed on the casing of the fourth stage of the nozzle guide vanes of the cold flow affordable near term low emission (ANTLE) LPT rig. These results are compared with those from a low speed linear cascade of similar LPT blades. In the four-stage LPT rig, a transitional boundary layer has been found on the platforms upstream of the leading edge of the blades. The boundary layer is more turbulent near the leading edge of the blade and for higher Reynolds numbers. Within the passage, for both the cold flow four-stage rig and the low speed linear cascade, the new inlet boundary layer formed behind the pressure leg of the horseshoe vortex is a transitional boundary layer. The transition process progresses from the pressure to the suction surface of the passage in the direction of the secondary flow.
Mathematical Modeling of Thermal Ablation in Tissue Surrounding a Large Vessel
Authors: Chen Xin , Saidel Gerald M.
Published: November 2008

Thermal ablation of a solid tumor in a tissue with radio-frequency (rf) energy can be accomplished by using a probe inserted into the tissue under the guidance of magnetic resonance imaging. The extent of the ablation can be significantly reduced by heat loss from capillary perfusion and by blood flow in a large vessel in the tissue. A mathematical model is presented of the thermal processes that occur during rf ablation of a tissue near a large blood vessel, which should not be damaged. Temperature distribution dynamics are described by the combination of a 3D bioheat transport in tissue together with a 1D model of convective-dispersive heat transport in the blood vessel. The objective was to determine how much of the tissue can be ablated without damaging the blood vessel. This was achieved by simulating the tissue temperature distribution dynamics and by determining the optimal power inputs so that a maximum temperature increase in the tissue was achieved without inducing tissue damage at the edge of the large vessel. The main contribution of this study is to provide a model analysis for pretreatment and, eventually, for intra-operative application to thermal ablation of a tumor located near a large blood vessel.
Syngas Production via High-Temperature Coelectrolysis of Steam and Carbon Dioxide
Authors: Stoots Carl M. , O’Brien James E. , Herring J. Stephen , Hartvigsen Joseph J.
Published: November 2008

This paper presents results of recent experiments on simultaneous high-temperature electrolysis (coelectrolysis) of steam and carbon dioxide using solid-oxide electrolysis cells. Coelectrolysis is complicated by the fact that the reverse shift reaction occurs concurrently with the electrolytic reduction reactions. All reactions must be properly accounted for when evaluating results. Electrochemical performance of the button cells and stacks was evaluated over a range of temperatures, compositions, and flow rates. The apparatus used for these tests is heavily instrumented, with precision mass-flow controllers, online dewpoint and CO2 sensors, and numerous pressure and temperature measurement stations. It also includes a gas chromatograph for analyzing outlet gas compositions. Comparisons of measured compositions to predictions obtained from a chemical equilibrium coelectrolysis model are presented, along with corresponding polarization curves. Results indicate excellent agreement between predicted and measured outlet compositions. Cell area-specific resistance values were found to be similar for steam electrolysis and coelectrolysis. Coelectrolysis significantly increases the yield of syngas over the reverse water gas shift-reaction equilibrium composition. The process appears to be a promising technique for large-scale syngas production.
A Hybrid Experimental Model of a Solid Oxide Fuel Cell Stack
Authors: Wu Xiao-Juan , Zhu Xin-Jian , Cao Guang-Yi , Tu Heng-Yong , Hu Wan-Qi
Published: November 2008

A multivariable hybrid experimental model of a solid oxide fuel cell stack is developed in this paper. The model consists of an improved radial basis function (RBF) neural network model and a pressure-incremental model. The improved RBF model is built to predict the stack voltage with different temperatures and current density. Likewise, the pressure-incremental model is constructed to predict the stack voltage under various hydrogen, oxygen, and water partial pressures. We combine the two models together and make a powerful hybrid multivariable model that can predict the voltage under any current density, temperature, hydrogen, oxygen, and water partial pressure. The validity and accuracy of modeling are tested by simulations, and the simulation results show that it is feasible to build the hybrid multivariable experimental model.
Thermoeconomic Modeling and Parametric Study of Hybrid Solid Oxide Fuel Cell-Gas Turbine-Steam Turbine Power Plants Ranging From 1.5MWeto10MWe
Authors: Arsalis Alexandros , von Spakovsky Michael R. , Calise Francesco
Published: November 2008

Detailed thermodynamic, kinetic, geometric, and cost models are developed, implemented, and validated for the synthesis/design and operational analysis of hybrid solid oxide fuel cell (SOFC)-gas turbine-steam turbine systems ranging in size from 1.5MWeto10MWe. The fuel cell model used in this research work is based on a tubular Siemens-Westinghouse-type SOFC, which is integrated with a gas turbine and a heat recovery steam generator (HRSG) integrated in turn with a steam turbine cycle. The current work considers the possible benefits of using the exhaust gases in a HRSG in order to produce steam, which drives a steam turbine for additional power output. Four different steam turbine cycles are considered in this research work: a single-pressure, a dual-pressure, a triple-pressure, and a triple-pressure with reheat. The models have been developed to function both at design (full load) and off-design (partial load) conditions. In addition, different solid oxide fuel cell sizes are examined to assure a proper selection of SOFC size based on efficiency or cost. The thermoeconomic analysis includes cost functions developed specifically for the different system and component sizes (capacities) analyzed. A parametric study is used to determine the most viable system/component syntheses/designs based on maximizing the total system efficiency or minimizing the total system life cycle cost.
Comparative Study of Membrane Humidifier and Enthalpy Wheel Humidifier for Large Power Fuel Cell System
Authors: Xingsheng Lao , Shihu Ma , Juntao Zhao , Hong Zeng , Weilin Zhuge , Yangjun Zhang
Published: November 2008

The performance of membrane humidifier (MH) and enthalpy wheel humidifier (EWH) for a large power proton exchange membrane fuel cell (PEMFC) system is compared using simulations and experiments. The MH model is based on one dimensional diffusion equation and the EWH model is based on the porous media surface diffusion equation. Simulation results agree well with experimental data. According to the results, the effect of intake air temperature has a lower effect on the MH performance than it does on the EWH performance while the air mass flow has a much higher effect on the MH performance than it does on the EWH performance. MH performs better than EWH at a low flow rate but worse at a high flow rate. Vapor transfer mechanism in the humidifiers is also studied.
Energy Analysis of a Residential Combined Heat and Power System Based on a Proton Exchange Membrane Fuel Cell 1
Authors: Minutillo M. , Perna A.
Published: November 2008

In this work the preliminary results of the research activity regarding the development of a microcogeneration unit prototype based on a proton exchange membrane fuel cell for residential application have been presented. The combined heat and power (CHP) system, which has been designed to optimize the integration of commercial and precommercial components, is equipped with two fuel cell stacks, a natural gas steam reforming unit, a heat recovery unit, electrical devices such as batteries, dc/ac converters, and auxiliary components such as compressors and pumps. In order to evaluate the electrical and thermal energy production and to estimate the system efficiency, an energy analysis has been carried out by using a numerical model. The simulation results pointed out that the microcogeneration system is able to provide 2.2 kWel and 2.5 kWth with electrical and CHP efficiencies (refer to the low heating value) of 40% and 88%, respectively. Furthermore, the primary energy savings, achievable by using the cogeneration system in comparison with a separate generation of electricity and heat from a centralized power plant and conventional boilers, have been evaluated.
Resistive Spot in a Fuel Cell Stack: Exact Solutions
Authors: Kulikovsky A. A.
Published: November 2008

We report the analytical solution to a problem of voltage and current distribution in a two-cell stack with the small amplitude resistive spot in one of the cells. Voltage disturbance in the defective cell increases almost linearly with the characteristic spot radius. The general expression for voltage loss due to a spot in an N-cell stack is obtained; it is stack current density times peak spot resistivity times square of the characteristic spot radius. Based on the solutions derived, a method for spot detection in a stack is discussed.
CFD and PTV Steady Flow Investigation in an Anatomically Accurate Abdominal Aortic Aneurysm
Authors: Boutsianis Evangelos , Guala Michele , Olgac Ufuk , Wildermuth Simon , Hoyer Klaus , Ventikos Yiannis , Poulikakos Dimos
Published: November 2008

There is considerable interest in computational and experimental flow investigations within abdominal aortic aneurysms (AAAs). This task stipulates advanced grid generation techniques and cross-validation because of the anatomical complexity. The purpose of this study is to examine the feasibility of velocity measurements by particle tracking velocimetry (PTV) in realistic AAA models. Computed tomography and rapid prototyping were combined to digitize and construct a silicone replica of a patient-specific AAA. Three-dimensional velocity measurements were acquired using PTV under steady averaged resting boundary conditions. Computational fluid dynamics (CFD) simulations were subsequently carried out with identical boundary conditions. The computational grid was created by splitting the luminal volume into manifold and nonmanifold subsections. They were filled with tetrahedral and hexahedral elements, respectively. Grid independency was tested on three successively refined meshes. Velocity differences of about 1% in all three directions existed mainly within the AAA sack. Pressure revealed similar variations, with the sparser mesh predicting larger values. PTV velocity measurements were taken along the abdominal aorta and showed good agreement with the numerical data. The results within the aneurysm neck and sack showed average velocity variations of about 5% of the mean inlet velocity. The corresponding average differences increased for all velocity components downstream the iliac bifurcation to as much as 15%. The two domains differed slightly due to flow-induced forces acting on the silicone model. Velocity quantification through narrow branches was problematic due to decreased signal to noise ratio at the larger local velocities. Computational wall pressure and shear fields are also presented. The agreement between CFD simulations and the PTV experimental data was confirmed by three-dimensional velocity comparisons at several locations within the investigated AAA anatomy indicating the feasibility of this approach.