bluuebunny/crossref_metadata_2025 huggingface dataset:
Prairie Wolf Slough Wetlands Demonstration Project: A Case Study Illustrating the Need for Incorporating Soil and Water Quality Assessment in Wetland Restoration Planning, Design and Monitoring
Authors: Montgomery James A. , Eames J. Marshall
Published: November 2008

In northeastern Illinois, restored wetlands are used to improve water quality in streams degraded by agriculture and urban development. Using freshwater wetlands to reduce nitrogen loading to lakes and rivers is well documented; however, there are fewer studies addressing their use to remove phosphorous. In 1998, a systematic water quality monitoring project was begun at Prairie Wolf Slough Wetland Demonstration Project, a restored palustrine emergent marsh wetland located on an abandoned farm field north of Chicago. The wetland drains 98 ha of mixed land uses into the Chicago River. Our objectives were to assess spatial and temporal variations in total suspended solids, soluble reactive and total phosphorous concentrations, and mass loadings and compute a mass balance and retention efficiency for these constituents. Water sampling was conducted from 1998 to 2003. In 2004, soil samples were collected from the marsh and an adjacent abandoned farm site and analyzed for soil test (Bray) phosphorus. The marsh effectively traps suspended solids but acts as a source of soluble reactive and total phosphorous to the river both during the growing and nongrowing seasons. Net export of phosphorous from the wetland was likely due to mobilization of orthophosphate as a result of anoxic conditions produced during inundation events. Often little consideration is given to the link between soil and water quality when locating restoration sites. Our study adds to a growing body of literature that clearly demonstrates the need for both soil and water quality assessments in wetland restoration planning, design, and monitoring.
Periodontal disease is associated with poor self‐rated oral health among Brazilian adults
Authors: Cascaes Andreia Morales , Peres Karen Glazer , Peres Marco Aurélio
Published: November 2008

Objective: The aim of this study was to investigate the association between periodontal disease and self‐rated oral health among Brazilian adults.

Material and Methods: Data on 11,874 adults in 250 cities from all the Brazilian regions were analysed. The outcome investigated was self‐rated oral health (dichotomized into “Good” and “Poor”) and the main exposure was periodontal disease defined as the combination of periodontal pocket depth 4 mm and clinical attachment loss 4 mm. Demographic characteristics, socioeconomic conditions, clinical oral health conditions (dental caries, dental and gingival pain, tooth loss and use of prosthesis) and use of dental services were the other explanatory variables. Simple and multivariate Poisson regression was performed allowing the estimation of prevalence ratios (PRs). All analyses were adjusted for the cluster sampling design.

Results: The prevalence of periodontal disease was 8.9% (95%CI 7.6–10.3) and poor self‐rated oral health was 23.6% (95%CI 21.9–25.2) which was significantly higher among those who presented periodontal disease (PR 1.4; 95%CI 1.2–1.5), after the adjustment for possible confounders.

Conclusions: Periodontal disease was associated with poor self‐rated oral health. The results of this study should be considered by population health planners in order to assess and plan periodontal services.
Context, Comparison, and Methodology in Chinese Management Research
Authors: Child John
Published: November 2008

In this paper, I accept Whetten's (2009) view that it is necessary to investigate Chinese management in a way that takes account of its context in order to assess the extent to which its features are context-specific or context-bounded. The first requirement, therefore, is to develop a way of conceptualising and measuring that context. A framework articulating material, ideational and institutional contextual features is offered to that end. Second, I argue that both ‘outside in’ and ‘inside out’ approaches to the study of Chinese management require comparison between China and other countries. Even a theory that claims uniqueness for China needs to have that claim tested through external comparison. We, therefore, have to employ a methodology that allows for valid comparisons between context and management in China and other countries. This paper focuses on these two issues of context and methodology with reference to comparative research. It examines them in turn and closes by arguing that the choice Barney and Zhang (2009) pose – between a Chinese theory of management and a theory of Chinese management – needs to be reframed within a more dynamic evolutionary perspective.
AtMGT7: An Arabidopsis Gene Encoding a Low‐Affinity Magnesium Transporter
Authors: Mao Dan‐Dan , Tian Lian‐Fu , Li Le‐Gong , Chen Jian , Deng Pei‐Yi , Li Dong‐Ping , Luan Sheng
Published: November 2008

Magnesium (Mg2+) is one of the essential cations in all cells. Although the Mg2+ transport mechanism has been well‐documented in bacteria, less is known about Mg2+ transporters in eukaryotes. The AtMGT gene family encoding putative magnesium transport proteins had been described previously. We report here that one of the Arabidopsis MGT family members, the AtMGT7 gene, encodes two mRNAs that have resulted from alternative splicing variants, designated AtMGT7a and AtMGT7b. Interestingly, the two mRNA variants were expressed with different patterns with AtMGT7a expressing in all organs, but AtMGT7b appearing only in root and flowers. The AtMGT7a variant functionally complemented a bacterial mutant lacking Mg2+ transport capacity, whereas AtMGT7b did not. The 63Ni2+ tracer uptake analysis in the bacterial model showed that AtMGT7a mediated low‐affinity transport of Mg2+. Consistent with the complementation assay result, 63Ni2+ tracer uptake analysis revealed that AtMGT7b did not transport Mg2+. This study therefore has identified from a higher plant the first low‐affinity Mg2+ transporter encoded by a gene with alternatively spliced transcripts that produce proteins with distinct functions.
THE COMPOSITION OF TWO SPANISH PEPPER VARIETIES (FRESNO DE LA VEGA AND BENAVENTE‐LOS VALLES) IN DIFFERENT RIPENING STAGES
Authors: BERNARDO ANA , MARTÍNEZ SIDONIA , ÁLVAREZ MARÍA , FERNÁNDEZ ANA , LÓPEZ MERCEDES
Published: November 2008

The chemical composition of two traditional varieties of Spanish peppers, “Fresno de la Vega” and “Benavente‐Los Valles” harvested in the provinces of León and Zamora, respectively, at different ripening stages (green mature, breaker and red) were evaluated. Herein we report the global composition, mineral and trace element contents, and the most relevant physicochemical parameters of each variety of pepper collected in 2 consecutive years. Both pepper varieties showed a similar chemical composition, except in vitamin C content, which resulted to be about 70% higher in Fresno de la Vega peppers. Red ripe fruits were high in total carbohydrates, fructose, glucose, sucrose, fat (64.5, 29.14, 25.57, 2.94, 1.79/100 g dry weight, respectively) and total soluble solids (6.83°Brix). Ascorbic acid content also increased progressively during ripening, reaching a mean value of 1.81 mg/100 g dry weight for Fresno de la Vega peppers. Potassium was the most abundant of the analyzed elements in the all samples, followed by phosphorus, magnesium, calcium and sodium. The order of the levels of the trace elements was iron > manganese > zinc > copper.

PRACTICAL APPLICATIONS

This report underscores the potential value of two traditional varieties of Spanish peppers and provides information on their composition during ripening to decide the proper harvesting time, which can be useful in the food industry.
AROMA COMPOUNDS AS MARKERS OF WINE QUALITY IN THE CASE OF MALVAZIJA ISTARSKA YOUNG WINE
Authors: LUKIĆ IGOR , PLAVŠA TOMISLAV , SLADONJA BARBARA , RADEKA SANJA , PERŠURIĆ ĐORDANO
Published: November 2008

In order to investigate the relationship between sensory and gas chromatographic analysis data, and to establish if particular aroma compounds could be used as Malvazija istarska young wine quality markers, 30 samples of Malvazija istarska young wine were subjected to sensory evaluation and gas chromatographic analysis of aroma compounds. Linear regression and principal component analysis were applied in order to establish the relations between sensory evaluation scores and aroma compound concentrations in corresponding wines. The most important contributors to the characterization and differentiation of wines evaluated with higher sensory evaluation scores were isoamyl acetate, ethyl hexanoate, ethyl octanoate, ethyl decanoate, hexanoic acid, octanoic acid and decanoic acid. On the other hand, wines evaluated with lower sensory evaluation scores were characterized and differentiated by higher amounts of isoamyl alcohol and isobutanol. Mentioned esters and acids were also found to be the most important variables for the classification of these wines according to quality using stepwise linear discriminant analysis (SLDA). The evaluation of the SLDA model was performed by cross‐validation, obtaining an average percentage of correct classification of 100.0%, and of correct prediction of 89.3%. The results of this investigation suggest that above‐mentioned esters, acids and alcohols could be used as markers of Malvazija istarska young wine quality.

PRACTICAL APPLICATIONS

Wine aroma is one of the most important parameters responsible for its quality, and hence for consumer acceptance. Sensory evaluation is the most common technique for controlling the organoleptic quality of wine, but it is not always feasible, since it requires specific conditions, and a group of trained expert tasters that can only assess a relatively small number of wine samples for a day. Moreover, the subjectivity of panelists can affect the evaluation in a great measure. The approach proposed in this work suggests the use of a nonsubjective instrumental technique such as gas chromatography for the analysis of volatile aroma compounds as a complementary tool for wine quality control able to predict, confirm or to correct the results of Malvazija istarska young wine sensory evaluation. Although this model is yet far from being practically implemented, information obtained could be used as a starting ground. Moreover, it was assumed that the approach proposed in this work is likely to be applied successfully on the differentiation and classification of other types of wine according to quality.
°BRIX/ACID RATIO AS A PREDICTOR OF CONSUMER ACCEPTABILITY OF CRIMSON SEEDLESS TABLE GRAPES
Authors: JAYASENA V. , CAMERON I.
Published: November 2008

Harvesting at correct time is essential for the supply of quality grapes. There is no standard method to determine the proper time of harvesting for table grapes. The applicability of objective measurements such as soluble solids concentration (°Brix), acid contents (titratable acidity) and °Brix/acid ratio of Crimson Seedless table grapes were evaluated as predictors of quality in terms of consumer acceptability. Crimson Seedless table grapes were harvested from two locations in Western Australia at weekly intervals for 5 weeks. The samples were density sorted to get berries of different maturity levels. Objective measurements and sensory evaluation (panel of 63 judges) were conducted. There were significant (P ≤ 0.05) differences in the degree of liking among grapes of 16.0–17.0, 17.1–18.0 and 19.1–20.0°Brix. Consumer liking of grapes substantially changed with a change in acidity. The data revealed correlation coefficients of determination (r2) of 0.58, 0.79 and 0.85 between overall consumer acceptability and °Brix, acidity, and °Brix/acid ratio, respectively. °Brix/acid ratio was found to be the best objective measurement that reflected the consumer acceptability and can be used as a reliable tool to determine the optimum harvesting stage of Crimson Seedless table grapes.

PRACTICAL APPLICATIONS

Crimson Seedless table grapes have been successfully grown in Australia since 1994, and they are gaining popularity with consumers day by day. However, means of determining proper time to harvest has not yet been established. This study, by examining the relationship between instrumental measurements and human perception of sensory characteristics of Crimson Seedless table grapes, will provide a simple but reliable instrumental method to predict the optimum harvest stage of Crimson Seedless table grapes. This will help in providing a quality product to the consumers while helping growers to get better return out of their produce.
EFFECT OF REPLACEMENT OF SUGAR WITH SUCRALOSE AND MALTODEXTRIN ON RHEOLOGICAL CHARACTERISTICS OF WHEAT FLOUR DOUGH AND QUALITY OF SOFT DOUGH BISCUITS
Authors: SAVITHA Y.S. , INDRANI D. , PRAKASH JAMUNA
Published: November 2008

The effect of replacement of 30% sugar with 0.05% sucralose and of different levels of maltodextrin (MD) on dough rheology and quality of biscuits was studied. The results showed that replacement of sugar with increasing amount of MD from 10 to 40% along with 0.05% sucralose influenced dough rheology. The farinograph water absorption increased up to 20% addition of MD and thereafter decreased. Objective evaluation of biscuits showed that the spread ratio of biscuits with 10% MD was 7.1, 20% MD was 7.8, 30% MD was 9.4 and 40% MD was 10.5, in comparison to control biscuits (9.9) with 30% sugar. The best overall quality score was reported for the control biscuits with 30% sugar, 69 out of the maximum score of 80, followed by 30% MD (65), 40% MD (60.5), 20% MD (54) and 10% MD (49.5). The results showed the possibility of replacing sugar in biscuit with sucralose and MD.

PRACTICAL APPLICATIONS

This article discusses the changes as a result of replacement of sugar with sucralose and maltodextrin (MD) in the rheological characteristics of wheat flour dough. The level of sucralose and MD required to replace sugar from control recipe in order to produce rheological characteristics of wheat flour dough comparable with that of the control has been highlighted in the article. This information will have a practical application in the production of sugar‐free soft dough biscuits.
RHEOLOGY AND TEXTURE OF SET YOGURT AS AFFECTED BY INULIN ADDITION
Authors: PASEEPHOL TATDAO , SMALL DARRYL M. , SHERKAT FRANK
Published: November 2008

The effect of inulin addition on rheology and texture of nonfat yogurt (NFY) was studied by the large (texture analyzer) and small (dynamic oscillatory rheometry) deformation tests. Skim milks (12% solids) were supplemented with three commercial chicory inulins with different chain lengths at 4% level and inoculated with mixed cultures of Lactobacillus delbrueckii ssp. bulgaricus and Streptococcus thermophilus. Textural and rheological tests were conducted after an overnight storage at 4C and during a shelf life of 28 days. A good correlation was observed between the two tests. During storage, all inulin‐containing yogurts in comparison with the control NFY were characterized by lower values of firmness, apparent viscosity, yield stress, complex viscosity, storage modulus and loss modulus. NFYs supplemented with long‐chain inulin demonstrated a rheological behavior closer to that of control full‐fat yogurt.

PRACTICAL APPLICATIONS

The use of inulin and oligofructose in the food industry has grown recently because of their interesting nutritional and technological properties. In the work presented here, three commercial inulin products with different chemical composition and functions were added to yogurt milk, and changes in rheological properties of yogurt were investigated in comparison with nonsupplemented control yogurts. According to the manufacturer's specifications, Raftiline HP and Raftiline GR are suitable for fat replacement because of the presence of long‐chain inulins, while Raftilose P95, being rich in mono‐ and disaccharides, is highly recommended for sugar replacement. The knowledge obtained from this study may be applied for the development of nonfat yogurts to satisfy the nutritional expectations of ever‐increasing health conscious consumers and at the same time to match the sensory and textural characteristics of full‐fat yogurt.
DEVELOPMENT OF A SOY‐BASED CREAM CHEESE
Authors: ZULKURNAIN MUSFIRAH , GOH MEI‐HUANG , KARIM ABDUL ALIAS , LIONG MIN‐TZE
Published: November 2008

Various amounts of blended tofu, oil, salt, carrageenan, pectin and maltodextrin were used to develop soy cream cheese products that were trans fat free, with texture properties similar to those of commercial dairy cream cheese. Response surface methodology predicted three formulations with similar spreadability value of that obtained from commercial cheese. Carrageenan and salt were useful to impart the desired firmness, while maltodextrin provided body to the product. Pectin introduced viscous behavior to the final texture but was proven useful in preventing syneresis. Rheological study at 25 and 4C manifested that, although the developed products mimicked the texture of the commercial sample, they had less elasticity. Chemical analysis revealed that the soy cream cheeses had lower fat and higher protein and fiber contents than the commercial sample. They were also stable against syneresis and oil separation over storage of 20 days.

PRACTICAL APPLICATIONS

The production of soy‐based products as alternatives to dairy products has attracted much attention recently. In addition to their lactose‐free and reduced fat content, soy‐based products are also a good source of protein. There has yet to be any published data on the development of a soy‐derivative cream cheese. This paper emphasizes the rheological development of soy cream cheeses in the presence of food hydrocolloids. Their main and interaction effects on texture properties were assessed to mimic those of dairy cream cheese. A comprehensive and systematic approach of formulating the soy cream cheeses was applied by using response surface methodology. In addition, the chemical and nutritional properties of the products were also evaluated and compared with those of the commercial dairy counterpart.
Apical transportation: Two assessment methods
Authors: López Fernanda Ullmann , Travessas Juliana Andréa Corrêa , Fachin Elaine , Fontanella Vania , Grecca Fabiana
Published: November 2008

Root canal transportation can lead to treatment failure. A large number of methodologies for assessing root canal preparation have been tried in the past. This study compared two methods for apical transportation measurement: digitised images of longitudinal root sections and radiographs. Sixty upper molar mesiobuccal root canals prepared for endodontic treatment were assessed. The results did not demonstrate statistically significant differences between the two imaging methods used to evaluate root canal transportation. The two methods were proven to be equally reliable.
Modelled female sale options demonstrate improved profitability in northern beef herds
Authors: Niethe GE , Holmes WE
Published: November 2008

Objective  To examine the impact of improving the average value of cows sold, the risk of decreasing the number weaned, and total sales on the profitability of northern Australian cattle breeding properties.

Design  Gather, model and interpret breeder herd performances and production parameters on properties from six beef‐producing regions in northern Australia.

Procedure  Production parameters, prices, costs and herd structure were entered into a herd simulation model for six northern Australian breeding properties that spay females to enhance their marketing options. After the data were validated by management, alternative management strategies were modelled using current market prices and most likely herd outcomes.

Results  The model predicted a close relationship between the average sale value of cows, the total herd sales and the gross margin/adult equivalent. Keeping breeders out of the herd to fatten generally improves their sale value, and this can be cost‐effective, despite the lower number of progeny produced and the subsequent reduction in total herd sales. Furthermore, if the price of culled cows exceeds the price of culled heifers, provided there are sufficient replacement pregnant heifers available to maintain the breeder herd nucleus, substantial gains in profitability can be obtained by decreasing the age at which cows are culled from the herd.

Conclusion  Generalised recommendations on improving reproductive performance are not necessarily the most cost‐effective strategy to improve breeder herd profitability. Judicious use of simulation models is essential to help develop the best turnoff strategies for females and to improve station profitability.
Persistent isolated hypocortisolism following brief treatment with trilostane
Authors: Ramsey IK , Richardson J , Lenard Z , Tebb AJ , Irwin PJ
Published: November 2008

A 12‐year‐old male neutered Miniature Poodle with confirmed pituitary‐dependent hyperadrenocorticism was treated with trilostane. After three doses, it developed clinical and laboratory changes suggestive of isolated hypocortisolism (‘atypical hypoadrenocorticism’), which persisted and progressed for more than 3 months despite immediate withdrawal of the trilostane. The clinical signs of hyperadrenocorticism resolved without further trilostane. After 3 months, prednisolone treatment was started and the clinical signs of hypocortisolism resolved. Prednisolone therapy was required for more than 1 year. Ultrasonography initially demonstrated large hypoechoic adrenal cortices, typical of dogs with hyperadrenocorticism, which then became small and heteroechoic, consistent with the development of adrenal necrosis. Persistent isolated hypocortisolism has not been reported previously as a complication of trilostane therapy. The case is also remarkable for the very short duration of trilostane therapy that elicited this complication. Clinicians should be aware that trilostane therapy may result in adrenal necrosis, even in the very earliest stages of therapy, but prompt action can prevent a life‐threatening situation.
Histopathological findings after ultraselective transcatheter arterial chemoembolization for hepatocellular carcinoma
Authors: Miyayama Shiro , Mitsui Takeshi , Zen Yoh , Sudo Yoshiko , Yamashiro Masashi , Okuda Miho , Yoshie Yuichi , Sanada Taku , Notsumata Kazuo , Tanaka Nobuyoshi , Matsui Osamu
Published: November 2008

Aim:  To evaluate the histopathologic findings in the surgical specimen of hepatocelluar carcinoma after transcatheter arterial chemoembolization (TACE) at the most distal portion of the sub‐subsegmental artery of the liver (ultraselective TACE).

Methods:  Histolopathologic findings from nine tumors with a mean diameter of 3.1 cm ± 1.7 from patients who underwent hepatectomy after ultraselective TACE were evaluated, especially with regard to the relationship between peritumoral liver parenchymal necrosis and portal vein visualization during TACE. Portal vein visualization was classified into three grades by a spot digital radiograph obtained just after TACE: 0, no obvious portal vein visualization; 1, visualization of the portal vein adjacent to the tumor; and 2, visualization in the whole embolized area or extending into the surrounding non‐embolized areas. Unenhanced computed tomography (CT) was obtained 1 week later and surgical resection was performed 37 ± 6.3 days after ultraselective TACE.

Results:  Portal vein visualization during TACE was classed as grade 1 in 5 tumors and grade 2 in 4. Histopathologically, complete tumor necrosis was observed in 7 tumors (77.8%). In 2 tumors (1 of grade 1, the other grade 2), a small viable portion or viable daughter nodule was seen. Macroscopic parenchymal necrosis adjacent to the tumor was observed in all 4 grade 2 tumors including gas‐containing areas on CT obtained 1 week after TACE.

Conclusions:  Ultraselective TACE induces not only complete tumor necrosis but also peritumoral parenchymal necrosis, similar to that after radiofrequency ablation, when the portal veins are markedly visualized during the TACE procedure.
Efficacy of platinum analogue for advanced hepatocellular carcinoma unresponsive to transcatheter arterial chemoembolization with epirubicin
Authors: Kawamura Yusuke , Ikeda Kenji , Hirakawa Miharu , Hosaka Tetsuya , Kobayashi Masahiro , Saitoh Satoshi , Yatsuji Hiromi , Sezaki Hitomi , Akuta Norio , Suzuki Fumitaka , Suzuki Yoshiyuki , Arase Yasuji , Kumada Hiromitsu
Published: November 2008

Aim:  Hepatocellular carcinoma (HCC) often shows resistance to transcatheter arterial chemoembolization (TACE). Such patients often have a poor prognosis and are unresponsive to other forms of therapy. The aim of this retrospective study was to determine the response to TACE using platinum analogues in patients deemed resistant to TACE using epirubicin.

Methods:  We studied 152 consecutive patients with advanced HCC resistant to TACE using epirubicin. All cases were treated with platinum analogue using transcatheter arterial chemotherapy with or without embolization.

Results:  Computed tomography at 3 months after therapy showed complete response (CR) in 6 patients (4.0%), partial response (PR) in 28 (18%), stable disease (SD) in 35 (23%), and progressive disease (PD) in 83 (55%). The cumulative survival rates for PR/CR patients who received platinum analogue‐transcatheter arterial chemotherapy with or without embolization (81.8% at first year, 53.9% at second year, and 33.1% at third year) were significantly higher than those of SD/PD patients (36.6%, 17.5% and 7.4%, respectively) (P < 0.001). The 50% survival period was extended almost 1.4 year in PR/CR patients who received platinum analogue‐transcatheter arterial chemotherapy with or without embolization.

Conclusion:  Our retrospective study is the first to report the efficacy of platinum analogues for advanced HCC unresponsive to TACE using epirubicin.
Exploiting the 1953 Agrarian Reform: Landlord Persistence in Northern Potosí, Bolivia
Authors: Goudsmit Into A.
Published: November 2008

La Reforma Agraria de 1953 también afectó el valle de Toracari en el norte de Potosí, Bolivia. No obstante, las cuantiosas propiedades que aun conservan los patrones en el valle muestran que ellos fueron más hábiles que los campesinos para aprovechar las oportunidades que brindó ese cambio político y económico. A partir de una investigación etnográfica e histórica, se indaga las particularidades de la tenencia de la tierra en Toracari y la compleja relación entre los patrones y los ayllus campesinos antes y después de la reforma agraria. Se propone que la interdependencia histórica entre los patrones y los campesinos y, paradójicamente, la nacionalización de las minas en 1952, llevada a cabo por el mismo gobierno que hizo la reforma, son factores explicativos de la persistencia del poder de los patrones en el valle. Los hallazgos presentados en este trabajo, motivan a reconsiderar la lectura convencional de la reforma agraria boliviana la cual pone énfasis en las transformaciones “estructurales” del campo boliviano.

The Bolivian Agrarian Reform of 1953, which had the aim of giving peasants title to land previously held by landlords, affected the valley of Toracari in Northern Potosí. The present scale of land owned by landlords in the valley shows, however, that they have been more successful than peasants in exploiting the changing political and economic environment. On the basis of ethnographic and archival research this study presents the details of landlord landholding and its complex relationship with peasantayllucommunities before and after the Reform. It argues that the mutual dependence between landlords and peasant households and, paradoxically, the nationalization of the mines in 1952 were key factors in explaining the persistence of landlords in the valley. This article puts into perspective the literature that highlights the “structural” changes brought about by the 1953 Agrarian Reform in the Bolivian countryside.
Film-Cooling Effectiveness on a Rotating Blade Platform
Authors: Suryanarayanan A. , Mhetras S. P. , Schobeiri M. T. , Han J. C.
Published: November 2008

Film cooling effectiveness measurements under rotation were performed on the rotor blade platform using a pressure sensitive paint (PSP) technique. The present study examines, in particular, the film cooling effectiveness due to purging of coolant from the wheel-space cavity through the circumferential clearance gap provided between the stationary and rotating components of the turbine. The experimental investigation is carried out in a new three-stage turbine facility, recently designed and taken into operation at the Turbomachinery Performance and Flow Research Laboratory (TPFL) of Texas A&M University. This new turbine rotor has been used to facilitate coolant injection through this stator-rotor gap upstream of the first stage rotor blade. The gap was inclined at 25deg to mainstream flow to allow the injected coolant to form a film along the passage platform. The effects of turbine rotating conditions on the blade platform film cooling effectiveness were investigated at three speeds of 2550rpm, 2000rpm, and 1500rpm with corresponding incidence angles of 23.2deg, 43.4deg, and 54.8deg, respectively. Four different coolant-to-mainstream mass flow ratios varying from 0.5% to 2.0% were tested at each rotational speed. Aerodynamic measurements were performed at the first stage stator exit using a radially traversed five-hole probe to quantify the mainstream flow at this station. Results indicate that film cooling effectiveness increases with an increase in the coolant-to-mainstream mass flow ratios for all turbine speeds. Higher turbine rotation speeds show more local film cooling effectiveness spread on the platform with increasing magnitudes.
Identification of the Stability Margin Between Safe Operation and the Onset of Blade Flutter
Authors: Rice Tim , Bell David , Singh Gurnam
Published: November 2008

The introduction of longer last stage blading in steam turbine power plant offers significant economic and environmental benefits. The modern trend, adopted by most leading steam turbine manufacturers, is to develop long last stage moving blades (LSMBs) that feature a tip shroud. This brings benefits of improved performance due to better leakage control and increased mechanical stiffness. However, the benefits associated with the introduction of a tip shroud are accompanied by an increased risk of blade flutter at high mass flows. The shroud is interlocked during vibration, causing the first axial bending mode to carry an increased, out of phase, torsional component. It is shown that this change in mode shape, compared to an unshrouded LSMB, can lead to destabilizing aerodynamic forces during vibration. At a sufficiently high mass flow, the destabilizing unsteady aerodynamic work will exceed the damping provided by the mechanical bladed-disk system, and blade flutter will occur. Addressing the potential for flutter during design and development is difficult. Simple tests prove inadequate as they fail to reveal the proximity of flutter unless the catastrophic condition is encountered. A comprehensive product validation program is presented, with the purpose of identifying the margin for safe operation with respect to blade flutter. Unsteady computational fluid dynamics predictions are utilized to identify the mechanisms responsible for the unstable aerodynamic condition and the particular modes of vibration that are most at risk. Using this information, a directed experimental technique is applied to measure the combined aerodynamic and mechanical damping under operating conditions. Results that demonstrate the identification of the aeroelastic stability margin for a new LSMB are presented. The stability margin predicted from the measurements demonstrates a significant margin of safety.
Gill Slot Trailing Edge Aerodynamics: Effects of Blowing Rate, Reynolds Number, and External Turbulence on Aerodynamic Losses and Pressure Distribution
Authors: Johnson J. D. , Fiala N. J. , Ames F. E.
Published: November 2008

Gill slots (also called cutbacks) are a common method to cool the trailing edge of vanes and blades and to eject spent cooling air. Exit surveys detailing total pressure loss, turning angle, and secondary velocities have been acquired for a gill slot vane in a large-scale, low speed cascade facility. These measurements are compared with exit surveys of the base (solid) vane configuration. Exit surveys have been taken over a four to one range in chord Reynolds numbers (500,000, 1,000,000, and 2,000,000) based on exit conditions and for low (0.7%), grid (8.5%), and aerocombustor (13.5%) turbulence conditions with varying blowing rate (50%, 100%, 150%, and 200% design flows). Exit loss, angle, and secondary velocity measurements were acquired in the facility using a five-hole cone probe at two stations representing axial chord spacings of 0.25 and 0.50. Differences between losses with and without the gill slot for a given turbulence condition and Reynolds number are compared providing evidence of coolant ejection losses and losses due to the separation off the gill slot lip. Additionally, differences in the level of losses, distribution of losses, and secondary flow vectors are presented for the different turbulence conditions and at the different Reynolds numbers. The turbulence condition has been found to have only a small effect on the increase in losses due to the gill slot. However, decreasing Reynolds number has been found to produce an increasing increment in losses. The present paper, together with a companion paper (2007, “Gill Slot Trailing Edge Heat Transfer—Effects of Blowing Rate, Reynolds Number, and External Turbulence on Heat Transfer and Film Cooling Effectiveness,” ASME Paper No. GT2007-27397), which documents gill slot heat transfer, is intended to provide designers with the heat transfer and aerodynamic loss information needed to compare competing trailing edge designs.
Time Resolved Experimental Investigations of an Axial Compressor With Casing Treatment
Authors: Emmrich R. , Hönen H. , Niehuis R.
Published: November 2008

A casing treatment with axial and radial skewed slots ending in a plenum chamber has experimentally been investigated at a highly subsonic axial compressor stage. The aim was to investigate the physical phenomenon of this treatment family that is responsible for the stabilization of the blade passage flow and the drop in efficiency mostly observed. The experimentally gained performance results of this configuration showed an extension of the operating range by approximately 50%, while the efficiency for design conditions is reduced by 1.4%. Apart from this, operating points at part load conditions have been observed nearly without any loss in efficiency. The detailed flow analysis is performed by means of results from a 3D pneumatic probe with temperature sensor and a dynamic total pressure probe. The focus of the investigations is on the incidence flow to the compressor rotor, the tip clearance vortex flow in combination with the wall stall separation region and the blade stall due to suction side separation. The casing treatment configuration is investigated with a special interest in detecting those effects which have an impact on the stability and the compressor overall efficiency, including the interaction of the rotor and the stator flow fields.
Effect of the Leakage Flows and the Upstream Platform Geometry on the Endwall Flows of a Turbine Cascade
Authors: de la Rosa Blanco E. , Hodson H. P. , Vazquez R.
Published: November 2008

This work describes the effect that the injection of leakage flow from a cavity into the mainstream has on the endwall flows and their interaction with a large pressure surface separation bubble in a low-pressure turbine. The effect of a step in hub diameter ahead of the blade row is also simulated. The blade profile under consideration is a typical design of modern low-pressure turbines. The tests are conducted in a low speed linear cascade. These are complemented by numerical simulations. Two different step geometries are investigated, i.e., a backward-facing step and a forward-facing step. The leakage tangential velocity and the leakage mass flow rate are also modified. It was found that the injection of leakage mass flow gives rise to a strengthening of the endwall flows independently of the leakage mass flow rate and the leakage tangential velocity. The experimental results have shown that below a critical value of the leakage tangential velocity, the net mixed-out endwall losses are not significantly altered by a change in the leakage tangential velocity. For these cases, the effect of the leakage mass flow is confined to the wall, as the inlet endwall boundary layer is pushed further away from the wall by the leakage flow. However, for values of the leakage tangential velocity around 100% of the wheel speed, there is a large increase in losses due to a stronger interaction between the endwall flows and the leakage mass flow. This gives rise to a change in the endwall flows’ structure. In all cases, the presence of a forward-facing step produces a strengthening of the endwall flows and an increase of the net mixed-out endwall losses when compared with a backward-facing step. This is because of a strong interaction with the pressure surface separation bubble.
Aerothermal Investigations of Tip Leakage Flow in Axial Flow Turbines—Part III: TIP Cooling
Authors: Newton P. J. , Lock G. D. , Krishnababu S. K. , Hodson H. P. , Dawes W. N. , Hannis J. , Whitney C.
Published: November 2008

Contours of heat transfer coefficient and effectiveness have been measured on the tip of a generic cooled turbine blade, using the transient liquid crystal technique. The experiments were conducted at an exit Reynolds number of 2.3×105 in a five-blade linear cascade with tip clearances of 1.6% and 2.8% chord and featuring engine-representative cooling geometries. These experiments were supported by oil-flow visualization and pressure measurements on the tip and casing and by flow visualization calculated using CFX, all of which provided insight into the fluid dynamics within the gap. The data were compared with measurements taken from the uncooled tip gap, where the fluid dynamics is dominated by flow separation at the pressure-side edge. Here, the highest levels of heat transfer are located where the flow reattaches on the tip surface downstream of the separation bubble. A quantitative assessment using the net heat flux reduction (NHFR) revealed a significant benefit of ejecting coolant inside this separation bubble. Engine-representative blowing rates of approximately 0.6–0.8 resulted in good film-cooling coverage and a reduction in heat flux to the tip when compared to both the flat tip profile and the squealer and cavity tip geometries discussed in Part 1 of this paper. Of the two novel coolant-hole configurations studied, injecting the coolant inside the separation bubble resulted in an improved NHFR when compared to injecting coolant at the location of reattachment.
Development of a Detailed Planar Solid Oxide Fuel Cell Computational
Fluid Dynamics Model for Analyzing Cell Performance Degradation
Authors: Verda Vittorio , von Spakovsky Michael R.
Published: November 2008

Solid oxide fuel cells (SOFC) are a promising technology for distributed electricity generation and cogeneration. Numerous papers have been published in the past several years proposing mathematical/computational fluid dynamics (CFD) models for predicting the transient and steady-state performance of such cells. In this paper, a detailed steady-state CFD model of a planar anode supported SOFC is proposed, which accounts for mass, thermal, and charge transport as well as electrochemistry and the chemistry of internal fuel reforming. Its main characteristics include the use of a continuous model for the electrochemistry, allowing one to examine different three-phase boundary geometries. This is an improvement over the typical model reported in literature, which utilizes an equivalent resistive circuit approach or a homogeneous distribution of three-phase boundaries. The model proposed here is used to simulate the degradation of anode, cathode, and electrolyte due to instabilities (e.g., anode oxidation due to fuel depletion) or to the delamination of the electrodes from the electrolyte. Such degradations result in a drop in cell performance but are difficult to predict without the use of models that can be helpful for diagnosis. The model is applied to experimental data available in literature both for the nondegraded and degraded cases.
Performance Improvement of a Proton Exchange Membrane Fuel Cell Through the Electrode Structure Change
Authors: Lee Ming-San , Chen Long-Jeng , Chen Ting-Huai
Published: November 2008

A new hydrophobic micropillared structure for the electrode of a proton exchange membrane fuel cell (PEMFC) is proposed in this study. Its performance has a 40% increase over the conventional structured electrode. The new design changes the gas-diffusion layer (also called microporous layer (MPL)) of the cathode of a PEMFC to a gas-abundant-layer (GAL) by mixing a high percentage of polytetrafluoroethylene (PTFE) into the carbon powder. Unlike the generally flat MPL, the surface of the GAL in contact with the catalyst layer has tens of thousands of micropillars on top of it so that its area can be increased significantly. The interfacial region between the GAL and the catalyst layer will become the main reaction sites because the heavily PTFE treated GAL will be filled with oxygen passageways while most of the catalyst layer of the cathode will eventually be filled with the water produced in the operation. The experimental results with different pillar sizes have shown that the area of the interfacial surface between the GAL and the catalyst layer is the key factor in determining the cell performance and should be made as large as possible.
Dynamic Analysis of Planar Solid Oxide Fuel Cell Models With Different Assumptions of Temperature Layers
Authors: Xi Handa , Sun Jing
Published: November 2008

As solid oxide fuel cell (SOFC) technology is rapidly evolving, high-fidelity mathematical models based on physical principles have become essential tools for SOFC system design and analysis. While several SOFC models have been developed by different groups using different modeling assumptions, little analysis of the effects of these assumptions on model performance can be found in literature. Meanwhile, to support system optimization and control design activities, a trade-off often has to be made between high fidelity and low complexity. This trade-off can be influenced by the number of temperature layers assumed in the energy balance to represent the SOFC structure. In this paper, we investigate the impact of the temperature layer assumption on the performance of the dynamic planar SOFC model. Four models of co-flow planar SOFCs are derived using the finite volume discretization approach along with different assumptions in the number of temperature layers. The model with four temperature layers is used as the baseline model, and the other models aimed at reducing the complexity of the baseline model are developed and compared through simulations as well as linear analysis. We show that the model with as few as two temperature layers—the solid structure and air bulk flow—is able to capture the dynamics of SOFCs, while assuming only one temperature layer results in significantly large modeling error.
The Cathode Airflow Effect on the Direct Methanol Fuel Cell From Single Cell to a Planar Module
Authors: Kuan Yean-Der , Lee Shi-Min , Sung Min-Feng
Published: November 2008

A series of experiments was conducted to examine the cathode airflow effect on a direct methanol fuel cell (DMFC) via the views of both airflow rate and airflow velocity from a single cell into a three-cell printed circuit board-based DMFC module. The objective of this paper is to discuss the relationship or difference between a single cell and a planar module. All experiments conducted were under constant anode fuel flow rate and operating temperature. The results show that the airflow supplied to a planar DMFC module does not just multiply the number of membrane electrode assemblies (MEAs) to a suitable airflow rate obtained from a single cell DMFC test. The results also show that the cathode airflow velocity effect is more significant than the airflow rate effect.
A Methodology for Building Up an Infrastructure of Haptically Enhanced Computer-Aided Design Systems
Authors: Zhu Weihang
Published: November 2008

This paper presents an infrastructure that integrates a haptic interface into a mainstream computer-aided design (CAD) system. A haptic interface, by providing force feedback in human-computer interaction, can improve the working efficiency of CAD/computer-aided manufacturing (CAM) systems in a unique way. The full potential of the haptic technology is best realized when it is integrated effectively into the product development environment and process. For large manufacturing companies this means integration into a commercial CAD system (Stewart, et al., 1997, “Direct Integration of Haptic User Interface in CAD Systems,” ASME Dyn. Syst. Control Div., 61, pp. 93–99). Mainstream CAD systems typically use constructive solid geometry (CSG) and boundary representation (B-Rep) format as their native format, while internally they automatically maintain triangulated meshes for graphics display and for numerical evaluation tasks such as surface-surface intersection. In this paper, we propose to render a point-based haptic force feedback by leveraging built-in functions of the CAD systems. The burden of collision detection and haptic rendering computation is alleviated by using bounding spheres and an OpenGL feedback buffer. The major contribution of this paper is that we developed a sound structure and methodology for haptic interaction with native CAD models inside mainstream CAD systems. We did so by analyzing CAD application models and by examining haptic rendering algorithms. The technique enables the user to directly touch and manipulate native 3D CAD models in mainstream CAD systems with force/touch feedback. It lays the foundation for future tasks such as direct CAD model modification, dynamic simulation, and virtual assembly with the aid of a haptic interface. Hence, by integrating a haptic interface directly with mainstream CAD systems, the powerful built-in functions of CAD systems can be leveraged and enhanced to realize more agile 3D CAD design and evaluation.
The Role of Haptic Technology in the Development of Aesthetic Driven Products
Authors: Bordegoni Monica , Cugini Umberto
Published: November 2008

This paper presents a haptic system the authors have developed for shape exploration in the field of industrial design. The system consists of a novel haptic-based digital technology, allowing designers to add the tactile experience to the visual one. The haptic interface developed allows designers to see and haptically feel through free hand motions an object surface during its creation and evolution. The system closes the loop of shape modification and its subsequent evaluation: It is possible to evaluate the “what if” related to a new product shape, applying the modification and comparing the solutions more and more times, and generate and maintain different versions. That improves the level of interaction of designers with the digital models, exploits their skills, and shortens the product development life cycle.