bluuebunny/crossref_metadata_2025 huggingface dataset:
COE Final Report: Chiba University
Authors: ISHIGAKI Kazuko , MOCHIZUKI Yuki , MASAKI Harue , MIYAZAKI Misako
Published: November 2008

Background:  The Center of Excellence (COE) program for the Creation and Dissemination of a New Japanese Nursing Science at the Chiba University School of Nursing aims to develop nursing science that is appropriate for Japanese culture and to internationally disseminate the importance of culturally based care. The object of this culturally appropriate nursing is not only clients/families but also nurses themselves, because although the cultural aspect of a nurse is tacit, it has deep influence on nursing care.

Method:  We organized our research subprojects from the viewpoint of “Interpersonal Helping,” which is different from the former approach of nursing, and we conducted research study on these subprojects. We conducted our research studies to clarify culturally appropriate nursing by the qualitative meta‐synthesis method. We performed international comparative research study on culturally appropriate nursing and conducted international conferences to elaborate and disseminate our outcomes.

Results:  Fourteen outcomes of meta‐synthesis studies have already been published until now, and more than 200 primary research studies have been conducted. We developed mainly 2 education programs and adopted them practically. From the inductive analysis of all our primary researches, we derived 4 viewpoints that clarify cultural aspect in nursing. The Cultural Nursing Society was established in 2007.

Conclusions:  We finally named this culturally appropriate nursing which respected the difference of individual culture “Cultural Nursing”. The importance of Cultural Nursing will further increase in the near future. We plan to establish and systematize this Cultural Nursing Science, which is based on the outcome of our program, and enroll researchers and nurses who have the ability to study and practice Cultural Nursing from both interdisciplinary and international aspects.
Five years activities of St. Luke's College of Nursing 21st Century COE program: Creation of People‐Centered Care
Authors: KOMATSU Hiroko
Published: November 2008

Aim:  Through the St. Luke's College of Nursing 21st Century Center of Excellence (COE) Program, we also aim to develop and serve as a center for Nursing for People‐Centered Initiatives in Healthcare and Health Promotion, which creates innovative ways of health care chiefly using partnerships and collaboration with people.

Methods:  Under the direct supervision of the president of St. Luke's College on Nursing, the program leader and COE Committee work together to ensure systematic coordination and control over research projects.

Results:  People‐centered initiatives in healthcare and health promotion have given efficient feedback of tacit knowing, gained from people's innate experience encompassing birth, aging, illness, and death, following collaborative research with care consumers. By applying such knowledge to nursing care, the initiatives could be theorized and verified as the formation of a healthy community in which limited medical resources efficiently circulate. The development of this practical theory marked a milestone, producing a paradigm shift in medical care from the “product‐out” to “market‐in” approach, the results of which led to worldwide collaborative research. Collaboration through the global network of our WHO center was also enhanced, facilitating diverse international collaborative projects. As a result, research and education programs involving the exchange of novice researchers and graduate students have been encouraged.

Conclusions:  Through our five‐year research activities, people‐centered care has come to characterize itself as a combined, cooperative care that promotes systematic service in a comprehensive manner to meet the needs of consumers.
CRAFTING KINSHIP AT HOME AND WORK: WOMEN MINERS IN WYOMING
Authors: Smith Jessica M.
Published: November 2008

The article traces the institutional policies and social dynamics shaping women's participation in the northeastern Wyoming mining industry. Ethnographic research suggests that the women's successful integration into this nontraditional workplace is predicated on their ability to craft and maintain kin‐like social relationships in two spheres. First, women miners have addressed the challenges of managing their home and work responsibilities by cultivating networks of friends and family to care for their children while they are at work. This finding denaturalizes the masculinization of the mining industry, showing instead how institutional policies such as rotating shift schedules have systematically made it difficult, though not impossible, for women and especially single mothers to participate in this industry. Second, women miners craft close relationships with coworkers in what are called “crew families.” These relationships make their work more enjoyable, and the ways in which they create camaraderie prompt a reconsideration of conventional accounts of sexual harassment in the mining industry.
“TAKING ONE'S PART IN THE REVOLUTION”: A COMPARISON OF WOMEN'S LABOR AS TOOLS OF REVOLUTIONARY CHANGE IN FRANCE, VIET NAM, AND POLAND
Authors: Stewart Pamela
Published: November 2008

This article assesses three events that traditionally highlight the labors of men, but which demonstrate the integral roles played by women's labor: the 1871 Paris Commune, Viet Nam's American War during the 1960s and early 1970s, and the rise of Poland's Solidarity during the 1980s. Arguing for increased and consistent attention to the hows and whys of women's participation in regime change and related warfare, this analysis exposes and compares gendered omissions in the customary narratives of these major events, revealing women's collective involvement in political upheavals and the warfare that can accompany them. This article argues that despite their obscured visibility, women nonetheless “took their place without begging for it,” demonstrating that women's collective labor contributed substantially to the maintenance, and potentially the outcome, of large‐scale political, military, and national actions.
Role of GA3, GA4 and Uniconazole‐P in Controlling Gravitropism and Tension Wood Formation in Fraxinus mandshurica Rupr. var. japonica Maxim. Seedlings
Authors: Jiang Sha , Xu Ke , Wang Yong‐Zhou , Ren Yan‐Ping , Gu Song
Published: November 2008

GA3 and GA4 (gibberellins) play an important role in controlling gravitropism and tension wood formation in woody angiosperms. In order to improve our understanding of the role of GA3 and GA4 on xylem cell formation and the G‐layer, we studied the effect of GA3 and GA4 and uniconazole‐P, which is an inhibitor of GA biosynthesis, on tension wood formation by gravity in Fraxinus mandshurica Rupr. var. japonica Maxim. seedlings. Forty seedlings were divided into two groups; one group was placed upright and the other tilted. Each group was further divided into four sub‐groups subjected to the following treatments: 3.43 × 10−9 μmol acetone as control, 5.78 × 10−8 μmol gibberellic acid (GA3), 6.21 × 10−8 μmol GA4, and 6.86 × 10−8 μmol uniconazole‐P. During the experimental period, GAs‐treated seedlings exhibited negative gravitropism, whereas application of uniconazole‐P inhibited negative gravitropic stem bending. GA3 and GA4 promoted wood fibers that possessed a gelatinous layer on the upper side, whereas uniconazole‐P inhibited wood formation but did not inhibit the differentiation of the gelatinous layer in wood fibers on the upper side. These results suggest that: (i) both the formation of gelatinous fibers and the quantity of xylem production are important for the negative gravitropism in horizontally‐positioned seedlings; (ii) GA3 and GA4 affect wood production more than differentiation of the gelatinous layer in wood fibers; G‐layer development may be regulated by other hormones via the indirect‐role of GA3 and GA4 in horizontally‐positioned F. mandshurica seedlings rather than the direct effect of GAs; and (iii) the mechanism for upward wood stem bending is different to the newly developed shoot bending in reaction to gravity in this species.
Synergistic Action between Jasmonic Acid and Nitric Oxide in Inducing Matrine Accumulation of Sophora flavescens Suspension Cells
Authors: Xu Mao‐Jun , Dong Ju‐Fang
Published: November 2008

Secondary metabolites not only play important ecological roles in plants but also are important pharmaceutical and source compounds for derivative synthesis. Production of plant secondary metabolites is believed to be controlled by the endogenous signal network of plants. However, the molecular basis is still largely unknown. Here we show that matrine production of Sophora flavescens Ait. cells treated with low levels of jasmonic acid (JA) and nitric oxide (NO) is significantly increased although treatment with low concentrations of JA or NO alone has no effects on matrine production, showing that JA and NO may act synergistically in triggering matrine production. Moreover, treatment with NO triggers lipoxygenase (LOX) activity and enhances JA levels of the cells, showing that NO may activate the endogenous JA biosynthesis of S. flavescens cells. External application of JA induces nitric oxide synthase‐like activities and stimulates NO generation of S. flavescens cells, which suggests that JA may trigger NO generation of the cells. Thus, the results reveal a mutually amplifying reaction between JA and NO in S. flavescens cells. Furthermore, JA and NO inhibitors suppress not only the mutually amplifying reaction between JA and NO but also the synergistic effects of NO and JA on matrine production. Therefore, the data demonstrate that the synergistic action of JA and NO in inducing matrine production might be due to the mutually amplifying reaction between JA and NO in the cells.
Cloning and Expression Analysis of Rice Sucrose Transporter Genes OsSUT2M and OsSUT5Z
Authors: Sun Ai‐Jun , Xu Hong‐Lin , Gong Wan‐Kui , Zhai Hong‐Li , Meng Kun , Wang Yong‐Qin , Wei Xiao‐Li , Xiao Gui‐Fang , Zhu Zhen
Published: November 2008

Two sucrose transporter (SUT) cDNAs, OsSUT2M and OsSUT5Z, were isolated from rice (Oryza sativa L.) by reverse transcription polymerase chain reaction (RT‐PCR). Sequencing results indicate they are 1 531 bp and 1 635 bp in length including complete open reading frame 1 506 bp and 1 608 bp, which encode 502 amino acids and 536 amino acids, respectively. The TopPred program suggested that both sucrose transporter proteins, OsSUT2M and OsSUT5Z, consist of potentially 12 transmembrane domains. Semi‐quantitative RT‐PCR was carried out to investigate the gene expression patterns of OsSUT2M and OsSUT5Z. In vegetative organs, transcripts of OsSUT2M were higher in source leaf blades than in other organs at the same development stage, whereas transcripts of OsSUT5Z were less traceable in all organs investigated. In reproductive organs, both transcripts of these two genes were high in panicles from the booting stage to 7 days after flowering (DAF) and then sharply declined. The potential physiology functions of these two sucrose transporters are discussed.
Heat shock protein translocation and expression response is attenuated in response to repeated eccentric exercise
Authors: Vissing K. , Bayer M. L. , Overgaard K. , Schjerling P. , Raastad T.
Published: November 2008

Aim:  This study hypothesized that heat shock protein (HSP) translocation and upregulation is more probable to occur after eccentric exercise than after concentric exercise or repeated eccentric exercise.

Methods:  Fourteen young, healthy, untrained male subjects completed two bench‐stepping exercise bouts with 8 weeks between bouts, and were compared with a control group (n = 6). Muscle biopsies collected from m. vastus lateralis of both legs prior to and at 3 h, 24 h and 7 days after exercise were quantified for mRNA levels and/or for HSP27, αβ‐crystallin and inducible HSP70 content in cytosolic and cytoskeletal protein fractions.

Results:  The first bout of exercise reduced muscle strength and increased muscle soreness predominantly in the eccentric leg (P < 0.05). These responses were attenuated after the repeated eccentric exercise bout (P < 0.05), suggesting a repeated bout adaptation. Increases in inducible HSP70 and HSP27 protein content in cytoskeletal fractions were observed exclusively after eccentric exercise (P < 0.05). For HSP27, an approx. 10‐fold upregulation after first‐bout eccentric exercise was attenuated to a an approximately fourfold upregulation after the repeated eccentric exercise bout. mRNA levels for HSP70, HSP27 and αβ‐crystallin were upregulated within approximately two to fourfold ranges at time points 3 and 24 h post‐exercise (P < 0.05). This upregulation was induced exclusively by eccentric exercise but with a tendency to attenuated expression 3 h after the repeated eccentric exercise bout.

Conclusion:  Our results show that HSP translocation and expression responses are induced by muscle damaging exercise, and suggest that such HSP responses are closely related to the extent of muscle damage.
Prospects of the practical use of silk sericins
Authors: SEHNAL František
Published: November 2008

In Lepidoptera and Trichoptera, a blend of sericin proteins seals the pair of fibroin filaments into the silk fiber that is coated by additional layers of adhesive sericins. The structure and function, and even the number of sericin proteins, are poorly known. Most sericin applications to date employ mixtures of proteins extracted by hot alkaline water during the cocoon processing in the reeling mills. The extracts were shown to have antioxidant, moistening, UV‐shielding and also moderate antibiotic properties. They are used as additives to various cosmetic products and in some countries also as remedies in human medicine. Sericins were reported to suppress tumor promotion, provide protection against ulcers and exert other health supporting effects. They also support proliferation and can provide a basic matrix for the differentiation of the cells cultured in vitro. Commercial production of sericin hydrolyzates as components of the tissue culture media will probably expand with the use of stem cells for the tissue repair. Sericins can polymerize to fibers, films and 3‐D structures that provide scaffolds for complex tissue reconstructions. The use of recombinant sericin‐type proteins for these applications is in the phase of basic investigations.
Advances in insect biotechnology for human welfare
Authors: MILLER Thomas A.
Published: November 2008

Biotechnology is the latest scientific breakthrough in the history of agriculture. Yet despite the promise of developing new tools for pest and disease control, transgenic organisms have encountered a mixed reception by the lay and scientific public alike. Yields are unable to keep pace with rising costs resulting in a decline in traditional farming. Switching to a new organic growing paradigm is occurring in Korea and the United States today. These new approaches ignore traditional tools that were responsible for the increased yields that support the current affluence and allowed us to protect crops while buying time to find more ecologically‐friendly methods. The perception that we understand crop diseases and pests is false and those making this assumption risk destabilizing global food production. There are new pests and diseases that are very difficult to control without these traditional non‐organic methods. Invasive species continue to arrive at high rates adding to the burden of farming. Global climate change is already causing changes in the pest and disease complexes and is forcing the entomologist and plant pathologist to make drastic changes to adjust to them.
Bombiculture: A fascinating insect industry for crop pollination in Korea
Authors: KWON Yong Jung
Published: November 2008

The Food and Agriculture Organization of the United Nations has recently taken on the leading roles internationally in the conservation and sustainable use of insect pollinators, which initiated the artificial rearing project of a European bumblebee of Bombus terrestris in Korea since 1999 (project number FAO/TCP/ROK/8921). The main purpose of the present project has focused on unveiling the production technology of B. terrestris for environmentally‐friendly crop pollination. Currently, the new establishment of a mass rearing system can be facilitated with compatibility commercially, and is expected to supply the domestic demand with reduced costs for the crop pollination. Therefore, bombiculture is a new technology in the entomological industry, utilizing one of the wild insect resources previously overlooked. This technology shows how the wild insects can contribute to our welfare as one of the useful biological resources.
Production of therapeutic proteins with baculovirus expression system in insect cell
Authors: AHN Mi‐Hyun , SONG Mira , OH Eun‐Yi , JAMAL Arshad , KIM HyunSoon , KO Kinarm , CHOO Young‐Kug , KIM Byung‐Jin , KO Kisung
Published: November 2008

Recombinant DNA technology has a major advantage in that it is capable of producing specific therapeutic proteins on demand in a heterologous expression system. The extent of this notion can be understood when one considers how crucial such proteins are, and how problematic the economical and safe production of such proteins are. Therapeutic recombinant protein production is a fundamental aspect of 21st century biotechnology industries. The improved therapeutic recombinant protein expression systems that use prokaryotic and eukaryotic cells have enabled the development of a multi‐billion dollar industry. Among the variety of available heterologous expression systems, the baculovirus‐based insect cell expression system has been utilized frequently for the high‐level production of therapeutic recombinant proteins. Thus, the baculovirus expression system has been recognized as one of the most powerful expression technologies for production, by virtue of the achievable amount and purity, and the ease of the eukaryotic production process. The majority of therapeutic proteins are glycoproteins originating from humans. The insect‐based expression system harbors glycosylation processing pathways, which constitute an advantage over other prokaryotic systems that lack glycosylation. However, there are several drawbacks which must be circumvented in order to establish an efficient system for the production of recombinant proteins. This review presents a brief overview of the perspective, particularly the glycosylation aspect, of the production of therapeutic recombinant proteins via a baculovirus‐based insect cell expression system.
Enzymatic Hydrolysis of Recovered Protein from Frozen Small Croaker and Functional Properties of Its Hydrolysates
Authors: Choi Yeung Joon , Hur Sungik , Choi Byeong‐Dae , Konno Kunihiko , Park Jae W.
Published: November 2008

ABSTRACT:  Fish protein isolate were recovered from frozen small croaker using pH shift. The partial enzymatic hydrolysates were fractionated as soluble and insoluble parts. They were dried using the drum dryer and their functional properties were examined. The total nitrogen content of the enzymatic hydrolysates ranged from 12.9% to 13.7%. The degree of hydrolysis of precipitates was 18.2% and 12.2% for croaker hydrolysates treated with Protamex 1.5 MG (Bacilllus protease complex) and Flavourzyme 500 MG (endoproteases and exoproteases, Aspergillus oryzae), respectively. The TCA supernatant, after centrifugation of hydrolysates, contained numerous peptides ranging from 100 to 4000 daltons. The solubility of the supernatants was higher than that of the precipitates at 0% to 3% NaCl and pH 2 to 10. The precipitate of Flavourzyme‐ and Protamex‐treated hydrolysates showed a high emulsion activity index value compared to egg white and bovine plasma protein. In addition, the highest emulsion stability was observed for Protamex‐treated precipitate hydrolysates. Emulsion stability of Protamex‐treated precipitate hydrolysates was comparable to those of protein additives (egg white, bovine plasma protein, and soy protein concentrate). Water and fat binding capacity of precipitates were higher than those of supernatant. The results indicate that precipitate hydrolysate from undersized croaker can be used in processed muscle foods as a functional and nutritional ingredient.
New Results on the Photochemistry of Biopterin and Neopterin in Aqueous Solution
Authors: Vignoni Mariana , Cabrerizo Franco M. , Lorente Carolina , Thomas Andrés H.
Published: November 2008

New photochemical studies of the reactivity of biopterin (BPT) and neopterin (NPT) in acidic (pH = 5.5) and alkaline (pH = 10.5) aqueous solutions at 350 nm and room temperature were performed. The photochemical properties of BPT are of particular interest because the photolysis of this compound takes place in the white skin patches of patients affected by vitiligo. The photochemical reactions were followed by UV/VIS spectrophotometry, HPLC, electrochemical measurement of dissolved O2 and enzymatic methods for hydrogen peroxide (H2O2) and superoxide anion (O2•−) determinations. When BPT or NPT are exposed to UVA radiation, a red intermediate, very likely 6‐formyl‐5,8‐dihydropterin, is generated in an O2‐independent process. That product is rapidly oxidized on admission of O2 to yield 6‐formylpterin and H2O2. When the photolysis takes place in aerobic conditions, no additional pathways exist. On the other hand, in the absence of O2, the intermediate generated is not stable and leads to the formation of many products. O2•− is also generated during photo‐oxidation of BPT and NPT. The quantum yields of reactant consumption depends on the O2 concentration: the higher the O2 concentration, the lower the quantum yields. This behavior is discussed in connection with the excited state of the pterins.
Genetic variability of the soil‐feeding termite Labiotermes labralis (Termitidae, Nasutitermitinae) in the Amazonian primary forest and remnant patches
Authors: DUPONT LISE , ROY VIRGINIE , BAKKALI ASMAE , HARRY MYRIAM
Published: November 2008

Abstract. 

Tropical rainforest fragmentation may increase the risk of extinction of limited dispersers such as soil‐feeding termites which play a fundamental role in soil structure and fertility.

We tested the hypothesis that population genetic structure of Labiotermes labralis, one of the most abundant soil‐feeders in the Amazonian primary forest, may vary in response to local ecological conditions.

As a pre‐requisite, two factors that may have important consequences on population genetic structure were examined: colony social organisation and infection by Wolbachia bacterium. This cytoplasmic endosymbiont is able to manipulate arthropod reproduction and thus, to alter patterns of mtDNA variation.

Three sites in French Guiana showing variable level of forest disturbance were studied. Three hundred and thirty‐eight neuters and 14 primary reproductives from 17 colonies were genotyped using six microsatellites to analyse colony and population genetic structure. Moreover, one sequence of the COII mitochondrial gene was obtained for each nest.

We showed that all nests were monogamous. In a single site, all nests were infected by the same Wolbachia strain. This pattern of infection was not associated to a particular mitochondrial haplotype.

In the most disturbed site, a significant inbreeding coefficient associated with high relatedness between primary reproductives suggested that anthropogenic habitat fragmentation has induced genetic isolation of the population; a result reinforced by the mitochondrial data. Thus, habitat fragmentation might have serious consequences for the persistence of L. labralis populations in French Guiana.
Radiation Benchmarking in a Model Combustor
Authors: Jiang Lei-Yong , Campbell Ian
Published: November 2008

Radiation heat transfer in a model combustor with interior and exterior conjugate heat transfers has been numerically studied. The previous investigations on turbulence, combustion, and scalar transfer modeling (Reynolds analogy), and comparisons with a comprehensive experimental database provide a reliable base to evaluate the effect of radiation heat transfer on the flow field and NO emission in the combustor. Some of the numerical results with and without radiation are presented and compared with the experimental measurements. It is found that the total radiation heat flux through the combustor wall is about 4.2% of the total energy released from the input fuel. The effect of radiation on the flow field is minor, particularly to the velocity field. In contrast, it has significant effects on the NO field, where the predicted values without radiation are two times higher than those with radiation or the experimental data. A considerable effect of radiation on the combustor wall temperature is also observed. In summary, to provide valuable predictions of NO emission and combustor liner temperature, the radiation heat transfer should be properly taken into account in numerical simulations.
Design, Fabrication, and Performance of Foil Gas Thrust Bearings for Microturbomachinery Applications
Authors: Dykas Brian , Bruckner Robert , DellaCorte Christopher , Edmonds Brian , Prahl Joseph
Published: November 2008

A methodology for the design and construction of simple foil thrust bearings intended for parametric performance testing and low marginal costs is presented. Features drawn from a review of the open literature are discussed as they relate to bearing performance. The design of fixtures and tooling required to fabricate foil thrust bearings is presented, using conventional machining processes where possible. A prototype bearing with dimensions drawn from literature is constructed, with all fabrication steps described. A load-deflection curve for the bearing is presented to illustrate structural stiffness characteristics. Start-stop cycles are performed on the bearing at a temperature of 425°C to demonstrate early-life wear patterns. A test of bearing load capacity demonstrates useful performance when compared with data obtained from the open literature.
Design and Performance Evaluation of a Trigeneration System Incorporating Hydraulic Storage and an Inverted Brayton Cycle
Authors: Blieske Matthew , Gauthier J. E. D. , Huang X.
Published: November 2008

To bring the economic benefit of trigeneration to small-scale users without incorporating expensive components, an inverted Brayton cycle (IBC) is employed, which makes use of the expander section already present in a microturbine. An air accumulator provides pressurized air, which is passed through the expander section of the same microturbine used to charge the accumulator. The air passing through the IBC is cooled due to expansion, simultaneously providing power and cooling the flow. As the microturbine is indirectly fired, the flow passing through the engine or IBC can be directly vented into the household—eliminating the need for additional heat exchangers. The size of the cycle studied is on the order of 10 kW(e), suitable for a domestic household; however, the system is easily scaled for larger commercial applications. The majority of the components in the system being studied are “off the shelf” products. A feasibility study was conducted to ensure that the proposed system is economically competitive with systems currently used, such as individual generation provided by an air conditioner (A/C), a high efficiency natural gas (NG) furnace, and grid power. Simulations were run for a full year based on the actual external temperature and the electrical and thermal loads for a single family detached dwelling located in Winnipeg, Canada. Performance data were generated using MATLAB™ while the economic performance was determined with time-based simulations conducted using SIMULINK™. The system is designed to allow energy islanding by providing for all household energy needs throughout the year; however, integration with a power grid is optional. It was found that the operating costs for the proposed trigeneration system in an energy islanding mode of operation were equivalent to or less than individual generation (A/C unit, NG furnace, and grid power) during heating modes of operation and were more expensive for cooling modes of operation. The yearly energy cost for the trigeneration system exceeded the individual generation costs by 30–40%; however, there remains much room for improvement to the trigeneration concept. All economic data were based on fair market energy prices as found in central Canada.
Nonlinear Numerical Prediction of Gas Foil Bearing Stability and Unbalanced Response
Authors: Le Lez Sébastien , Arghir Mihaï , Frêne Jean
Published: November 2008

One of the main interests of gas foil bearings lies in their superior rotordynamic characteristics compared with conventional bearings. A numerical investigation on the stability limit and on the unbalanced response of foil bearings is presented in this paper. The main difficulty in modeling the dynamic behavior of such bearings comes from the dry friction that occurs within the foil structure. Indeed, dry friction is highly nonlinear and is strongly influenced by the dynamic amplitude of the pressure field. To deal with these nonlinearities, a structural dynamic model has been developed in a previous work. This model considers the entire corrugated foil and the interactions between the bumps by describing the foil bearing structure as a multiple degrees of freedom system. It allows the determination of the dynamic friction forces at the top and at the bottom of the bumps by simple integration of ordinary differential equations. The dynamic displacements of the entire corrugated sheet are then easily obtained at each time step. The coupling between this structural model and a gas bearing prediction code is presented in this paper and allows performing full nonlinear analyses of a complete foil bearing. The bearing stability is the first investigated problem. The results show that the structural deflection enhances the stability of compliant surface bearings compared with rigid ones. Moreover, when friction is introduced, a new level of stability is reached, revealing the importance of this dissipation mechanism. The second investigated problem is the unbalanced response of foil bearings. The shaft trajectories depict a nonlinear jump in the response of both rigid and foil bearings when the value of the unbalance increases. Again, it is evidenced that the foil bearing can support higher mass unbalance before this undesirable step occurs.
Damping Ratio Estimation Techniques for Rotordynamic Stability Measurements
Authors: Cloud C. Hunter , Maslen Eric H. , Barrett Lloyd E.
Published: November 2008

Rotor stability is most commonly estimated using methods derived from a simple single degree of freedom system. When the modes of more complex systems, such as rotors, are closely spaced, we demonstrate that such methods can yield very poor estimates of the modal stability (damping ratio). Multiple output backward autoregression (MOBAR) is proposed as an alternative approach and is demonstrated to yield reasonably accurate estimates of modal damping even when modes are closely spaced. The performance of the MOBAR approach is then examined on an experimental rotor in tilt-pad bearings, demonstrating good performance in a realistic measurement setting.
A Generalized Likelihood Ratio Test for Adaptive Gas Turbine Performance Monitoring
Authors: Borguet S. , Léonard O.
Published: November 2008

Kalman filters are widely used in the turbine engine community for health monitoring purposes. This algorithm has proven its capability to track gradual deterioration with good accuracy. On the other hand, its response to rapid deterioration is a long delay in recognizing the fault and/or a spread of the estimated fault on several components. The main reason for this deficiency lies in the transition model of the parameters that is blended in the Kalman filter and assumes a smooth evolution of the engine condition. This contribution reports the development of an adaptive diagnosis tool that combines a Kalman filter and a secondary system that monitors the residuals. This auxiliary component implements a generalized likelihood ratio test in order to detect and estimate an abrupt fault. The enhancement in terms of accuracy and reactivity brought by this adaptive Kalman filter is highlighted for a variety of simulated fault cases that may be encountered on a commercial aircraft engine.
High Temperature Radiation Heat Transfer Performance of Thermal Barrier Coatings With Multiple Layered Structures
Authors: Huang Xiao
Published: November 2008

Meeting the demands for ever increasing operating temperatures in gas turbines requires concurrent development in cooling technologies, new generations of superalloys, and thermal barrier coatings (TBCs) with increased insulation capability. In the case of the latter, considerable research continues to focus on new coating material compositions, the alloying/doping of existing yttria stabilized zirconia ceramics, and the development of improved coating microstructures. The advent of the electron beam physical vapor deposition coating process has made it possible to consider the creation of multiple layered coating structures to meet specific performance requirements. In this paper, the advantages of layered structures are first reviewed in terms of their functions in impeding thermal conduction (via phonons) and thermal radiation (via photons). Subsequently, the design and performance of new multiple layered coating structures based on multiple layered stacks will be detailed. Designed with the primary objective to reduce thermal radiation transport through TBC systems, the multiple layered structures consist of several highly reflective multiple layered stacks, with each stack used to reflect a targeted radiation wavelength range. Two ceramic materials with alternating high and low refractive indices are used in the stacks to provide multiple-beam interference. A broadband reflection of the required wavelength range is obtained using a sufficient number of stacks. In order to achieve an 80% reflectance to thermal radiation in the wavelength range 0.3–5.3μm, 12 stacks, each containing 12 layers, are needed, resulting in a total thickness of 44.9μm. Using a one dimensional heat transfer model, the steady state heat transfer through the multiple layered TBC system is computed. Various coating configurations combining multiple layered stacks along with a single layer are evaluated in terms of the temperature profile in the TBC system. When compared with a base line single layered coating structure of the same thickness, it is estimated that the temperature on the metal surface can be reduced by as much as 90°C due to the use of multiple layered coating configurations. This reduction in metal surface temperature, however, diminishes with increasing the scattering coefficient of the coating and the total coating thickness. It is also apparent that using a multiple layered structure throughout the coating thickness may not offer the best thermal insulation; rather, placing multiple layered stacks on top of a single layer can provide a more efficient approach to reducing the heat transport of the TBC system.
Nonlinear Stochastic Dynamics, Chaos, and Reliability Analysis for a Single Degree of Freedom Model of a Rotor Blade
Authors: Kumar Pankaj , Narayanan S.
Published: November 2008

In turbomachinery, the analysis of systems subjected to stochastic or periodic excitation becomes highly complex in the presence of nonlinearities. Nonlinear rotor systems exhibit a variety of dynamic behaviors that include periodic, quasiperiodic, chaotic motion, limit cycle, jump phenomena, etc. The transitional probability density function (PDF) for the random response of nonlinear systems under white or colored noise excitation (delta-correlated) is governed by both the forward Fokker–Planck (FP) and backward Kolmogorov equations. This paper presents efficient numerical solution of the stationary and transient form of the forward FP equation corresponding to two state nonlinear systems by standard sequential finite element (FE) method using C0 shape functions and Crank–Nicholson time integration scheme. For computing the reliability of system, the transient FP equation is solved on the safe domain defined by D barriers using the FE method. A new approach for numerical implementation of path integral (PI) method based on non-Gaussian transition PDF and Gauss–Legendre scheme is developed. In this study, PI solution procedure is employed to solve the FP equation numerically to examine some features of chaotic and stochastic responses of nonlinear rotor systems.
Relationship of Influence Coefficients Between Static-Couple and Multiplane Methods on Two-Plane Balancing
Authors: Yu John J.
Published: November 2008

This paper demonstrates analytical relationship of influence coefficients between static-couple and multiplane methods on two-plane balancing as well as its application. For the static-couple approach, cross-effects are defined between static weights and couple response as well as between couple weights and static response, thus making it possible to offset both static and couple vibration vectors effectively with appropriate combination of static and couple weights. Relationship of influence coefficients between static/couple and individual probe due to static/couple weights is also given. Static, couple, or individual probe influence coefficients due to static or couple weights can be obtained directly without having to place static or couple trial weights if influence coefficients used in the multiplane approach are known. From static and couple influence data as well as cross-effects, influence data for the multiplane approach can be obtained directly as well without having to place any trial weights at either plane. The above findings and conversion equations are obtained analytically and verified by experimental results. Conversion of influence coefficients from multiplane to static-couple format can determine whether static or couple weights are more effective as well as running vibration modes, while conversion from static-couple to multiplane format can determine which balance plane is more effective.
Cyclic Carbonation Calcination Studies of Limestone and Dolomite for CO2 Separation From Combustion Flue Gases
Authors: Senthoorselvan Sivalingam , Gleis Stephan , Hartmut Spliethoff , Yrjas Patrik , Hupa Mikko
Published: November 2008

Naturally occurring limestone and dolomite samples, originating from different geographical locations, were tested as potential sorbents for carbonation/calcination based CO2 capture from combustion flue gases. Samples have been studied in a thermogravimetric analyzer under simulated flue gas conditions at three calcination temperatures, viz., 750°C, 875°C, and 930°C for four carbonation calcination reaction (CCR) cycles. The dolomite sample exhibited the highest rate of carbonation than the tested limestones. At the third cycle, its CO2 capture capacity per kilogram of the sample was nearly equal to that of Gotland, the highest reacting limestone tested. At the fourth cycle it surpassed Gotland, despite the fact that the CaCO3 content of the Sibbo dolomite was only 2/3 of that of the Gotland. Decay coefficients were calculated by a curve fitting exercise and its value is lowest for the Sibbo dolomite. That means, most probably its capture capacity per kilogram of the sample would remain higher, well beyond the fourth cycle. There was a strong correlation between the calcination temperature, the specific surface area of the calcined samples, and the degree of carbonation. It was observed that the higher the calcination temperature, the lower the sorbent reactivity. The Brunauer–Emmett–Teller measurements and scanning electron microscope images provided quantitative and qualitative evidences to prove this. For a given limestone/dolomite sample, sorbent’s CO2 capture capacity depended on the number of CCR cycles and the calcination temperature. In a CCR loop, if the sorbent is utilized only for a certain small number of cycles (<20), the CO2 capture capacity could be increased by lowering the calcination temperature. According to the equilibrium thermodynamics, the CO2 partial pressure in the calciner should be lowered to lower the calcination temperature. This can be achieved by additional steam supply into the calciner. Steam could then be condensed in an external condenser to single out the CO2 stream from the exit gas mixture of the calciner. A calciner design based on this concept is illustrated.
Comparison of Unsteady Reynolds Averaged Navier–Stokes and Large Eddy Simulation Computational Fluid Dynamics Methodologies for Air Swirl Fuel Injectors
Authors: Dunham David , Spencer Adrian , McGuirk James J. , Dianat Mehriar
Published: November 2008

It is well documented that various large-scale quasiperiodic flow structures, such as a precessing vortex core (PVC) and multiple vortex helical instabilities, are present in the swirling flows typical of air swirl fuel injectors. Prediction of these phenomena requires time-resolved computational methods. The focus of the present work was to compare the performance and cost implications of two computational fluid dynamics (CFD) methodologies—unsteady Reynolds averaged Navier–Stokes (URANS) using a k-ε model and large eddy simulation (LES) for such flows. The test case was a single stream radial swirler geometry, which has been the subject of extensive experimental investigation. Both approaches captured the gross (time-mean) features of strongly swirling confined flows in reasonable agreement with experiment. The temporal dynamics of the quadruple vortex pattern emanating from within the swirler and observed experimentally were successfully predicted by LES, but not by URANS. Spectral analysis of two flow configurations (with and without a central jet) revealed various coherent frequencies embedded within the broadband turbulent frequency range. LES reproduced these characteristics, in excellent agreement with experimental data, whereas URANS predicted the presence of coherent motions but at incorrect amplitudes and frequencies. For the no-jet case, LES-predicted spectral data indicated the occurrence of a PVC, which was also observed experimentally for this flow condition; the URANS solution failed to reproduce this measured trend. On the evidence of this study, although k-ε based URANS offers considerable computational savings, its inability to capture the temporal characteristics of the flows studied here sufficiently accurately suggests that only LES-based CFD, which captures the stochastic nature of the turbulence much more faithfully, is to be recommended for fuel injector flows.
Thermal-Design Options for Pressure-Channel SCWRS With Cogeneration of Hydrogen
Authors: Naidin Maria , Mokry Sarah , Baig Farina , Gospodinov Yevgeniy , Zirn Udo , Pioro Igor , Naterer Greg
Published: November 2008

Currently there are a number of Generation IV supercritical water-cooled nuclear reactor (SCWR) concepts under development worldwide. The main objectives for developing and utilizing SCWRs are (1) to increase the gross thermal efficiency of current nuclear power plants (NPPs) from 33–35% to approximately 45–50% and (2) to decrease the capital and operational costs and, in doing so, decrease electrical-energy costs (approximately US$ 1000∕kW or even less). SCW NPPs will have much higher operating parameters compared to current NPPs (i.e., pressures of about 25MPa and outlet temperatures of up to 625°C). Additionally, SCWRs will have a simplified flow circuit in which steam generators, steam dryers, steam separators, etc. will be eliminated. Furthermore, SCWRs operating at higher temperatures can facilitate an economical cogeneration of hydrogen through thermochemical cycles (particularly, the copper-chlorine cycle) or direct high-temperature electrolysis. To decrease significantly the development costs of a SCW NPP and to increase its reliability, it should be determined whether SCW NPPs can be designed with a steam-cycle arrangement that closely matches that of mature supercritical (SC) fossil power plants (including their SC turbine technology). On this basis, several conceptual steam-cycle arrangements of pressure-channel SCWRs, their corresponding T‐s diagrams and steam-cycle thermal efficiencies are presented in this paper together with major parameters of the copper-chlorine cycle for the cogeneration of hydrogen. Also, bulk-fluid temperature and thermophysical properties profiles were calculated for a nonuniform cosine axial heat-flux distribution along a generic SCWR fuel channel, for reference purposes.
Effects of Surface Tension on Two-Phase Void Drift Between Triangle Tight Lattice Subchannels
Authors: Kawahara Akimaro , Sadatomi Michio , Higuchi Tatsuya
Published: November 2008

In this study, void drift phenomena, which are one of three components of the intersubchannel fluid transfer, have been investigated experimentally and analytically. In the experiments, data on flow and void redistributions were obtained for hydraulically nonequilibrium flows in a multiple channel consisting of two subchannels simplifying a triangle tight lattice rod bundle. In order to know the effects of the reduced surface tension on the void drift, water and water with a surfactant were used as test liquids. In addition, data on the void diffusion coefficient, D̃, needed in a void drift model, have been obtained from the redistribution data. In the analysis, the flow and the void redistributions were predicted by a subchannel analysis code based on a one-dimensional two-fluid model. From a comparison between the experiment and the code prediction, the present analysis code was found to be valid against the present data if newly developed constitutive equations of wall and interfacial friction were incorporated in to the model to account for the reduced surface tension effects.
On the Pressure Dependency of Physical Parameters in Case of Heat Transfer Problems of Supercritical Water
Authors: Hazi Gabor , Farkas Istvan
Published: November 2008

Studying heat transfer problems of supercritical water, the pressure dependency of thermophysical parameters (density, specific heat, viscosity, and thermal conductivity) and the work done by pressure are often neglected. Here we show that the variations of some physical parameters as functions of pressure have the same order of magnitude than their variations as functions of temperature in supercritical water. Therefore, pressure dependency of physical parameters should be taken into account in heat transfer calculations of supercritical water. It is also pointed out that the work done by pressure should not be neglected in supercritical water since the pressure work term has the same order of magnitude than the convective term near the pseudocritical temperature.
Computational Fluid Dynamics Assessment of the Local Hot Core Temperature in a Pebble-Bed Type Very High Temperature Reactor
Authors: Kim Min-Hwan , Lim Hong-Sik , Lee Won Jae
Published: November 2008

Assessment of the local hot core temperature during normal operation in a pebble-bed type very high temperature reactor has been carried out by using the computational fluid dynamic (CFD) method for which the boundary conditions were obtained from the results of a macroscopic analysis of the core using a system thermal analysis code, GAMMA. Three pebble arrangements are selected, which are simple cubic (SC), body-centered cubic, and face-centered cubic. The results showed that the SC arrangement having the lowest porosity gives the highest fuel temperature of 1237°C but still below the normal operational fuel limit of 1250°C. Comparison of the CFD results with an empirical correlation was made for the pressure drop and Nusselt number. Both results showed a similar tendency that the pressure drop and the Nusselt number increases as the porosity decreases but there were large differences in their absolute values. The benchmark calculation for the pressure drop of the packed particles in a square channel indicated that the correlation for the full core used in the system code is not appropriate for the prediction of a local thermal-fluid behavior in an ordered pebble arrangement.