bluuebunny/crossref_metadata_2025 huggingface dataset:
‘Mission‐Shaped Presence’in Europe
Authors: Jackson Darrell
Published: March 2009

In describing ‘mission‐shaped presence’ and contrasting it with ecclesial forms of Christian presence, I suggest that mission‐shaped presence is essential to the theological renewal of current eccle‐siopraxis.

My treatment falls into three sections. Initially I attempt an impressionistic portrait of important distinctions between two forms of Christian presence; one is characterized as ecclesial, the other as missionaL Secondly, I offer several brief descriptions of what may be called forms ofmis‐sion‐shaped presence. Finally, I theorize sociogically about this dialectic using the work of Anthony Guldens on structuration, and the way in which this beau upon an understanding of the institutions of modernity.

This leads us to conclude that mission‐shaped forms of Christian presence, though vitally important, are transitional forms that stimulate and orient the journey towards a truly post‐modern expression of the church of Jesus Christ. From this perspective, the process of reflexive action within these forms of mission‐shaped presence is arguably more important than the particular forms themselves.
A New Confession of Faith With an Eco‐Theology and a Father‐Centred Trinitarianism: a Critical Study of the 2ist Century Confession of Faith of the Presbyterian Church of Korea
Authors: Hwang Jae‐Buhm
Published: March 2009

A mainstream Korean Protestant church has recently produced a noticeable confession of faith that includes two distinctive elements: eco‐theology and Father‐centred trinitarianism. The eco‐theoiogical position of the confession emphasizes the whole creation's participation in God's saving works, and declares humans'solidarity with all other creatures. However, this results in weakening the Reformed doctrine of God's free and covenantal dealing with humans. The confession also includes a thorough trinitarianism that turns out to be a Father‐centred trinitarianism. This significantly weakens the Christology and pneumatology of the confession, and may reflect a Confucian and patriarchal way of thinking by the Korean church.
Choosing Life or Second Life? Discipleship and Agency in A Mediated Culture
Authors: Halt Gary P.
Published: March 2009

Liberationist theologies gave rue to a re‐emphasis on Christian life as being primarily historical life, and Christian spirituality as rooted in faithful and honest attention to the immediacy of historical reality. However, for many people living in media‐saturated, overdeveloped societies, any distinction between actual reality and a mediated pseudo‐reality is blurred. Another facet of life in a media‐saturated context is that of being regularly confronted with impressions of destitution, violence and ecological degradation, whilst at the same time being further distanced from the realities represented through communications media and their ‘virtualizing’ tendency. This rapid change in our relation to reality has, I suggest, profound theological and missiological consequences. The ways in which electronic media have modified life, including religious life, are complex and varied. Consumption of electronic media does not seem to have replaced religion as such but it has tended to shape religious life in its own image. With particular reference to Slavoj Zizek's reading of “the Real” after “9/11”, I have attempted to sketch how some of these sweeping social and cultural changes may impact on the interpretation of Christian discipleship and mission. In the end, either the Christian life is vulnerable to potentially disruptive reality, or it is at risk of collapsing into a version of the pursuit of happiness mediated by and through late‐capitalist culture.
Getting Saved in El Salvador: The Preferential Option for the Poor
Authors: Wadkins Timothy
Published: March 2009

This essay it an ethnographic analysis of the Evangelical1and Pentecostal movement that, like elsewhere in Latin America, are sweeping across El Salvador and threatening to upset the historic dominance of the Roman Catholic Church in the region. Based on the latest information from country‐wide surveys, as well as extensive interviews with clerical leaders, church members, social scientists, politicians, converts and critics, the essay looks deeply into this revival from the standpoint of what most Salvadorian Catholics, liberal Protestants and Liberationists see as its greatest weaknesses, viz. its first‐world missionary antecedents and its passivity toward political and social engagement. The essay concluded by contending that despite the often warranted criticism, this revival it nevertheless producing important social capital, particularly among El Salvador's poor. There is evidence that it could, over time, have a dramatic impact on the political and economic structures of Salvadorian society, even in radical ways envisioned by liberation theologians.
A Postcolonial Theological Project: Creating Space for the Studies of World Christianity
Authors: Pang Samuel Yunsang
Published: March 2009

In this global and culturally pluralistic context we are in, what is being proposed here is that our theological focal point should be on humanity as a relation of beings in dialogue, who are attempting to be open toward the future and to overcome the limits of each other. In this sphere, what is important is the necessity of how to think and act truthfully and faithfully in the continuation and the development of dialogical relations. The partners in dialogue, or interlocutors in dialogue, should accept each other as those who have an inalienable right and an unconditional obligation, and learn from each other in developing “togetherness”. In a way, togetherness is the beginning and end of dialogical relation, even in ever changing situations, which means that the temporal togetherness is also to be open and dialogued in the future dialogue. This is a dialogical event in which the meaning of truth defines and confirms itself because the truth of being is actualized in the figure of dialogical relation.
Mission as Transformation: An Exploration of the Relationship Between Mission and Development
Authors: Si Oliver Byar Bowh
Published: March 2009

This article attempts to articulate a theology that explores the relationship between mission and development. It conceptually engages in theological themes, especially the concepts of love, justice and freedom. It also discusses the meaning of missio Dei and its relation to the church. Moreover, it examines the relation between mission as liberation and Sen's philosophy of development. It is hoped that Sen's revolutionary idea of development based on the concept of “freedom” will offer a significant contribution to the understanding of a contemporary theology of mission. The essay is written from an activist theological approach to mission as transformation.
A Dissonant Mission: Stephen Neill, Amy Carmichael, and Missionary Conflict in South India
Authors: Daughrity Dyron
Published: March 2009

In 1924, eminent church historian and missiolagist Stephen Neill began his career as a missionary to south India under the supervision of the celebrated Amy Carmichael. What seemed like a match made in heaven resulted in a bitter parting of ways. How could such a promising mission partnership go so wrong? This paper draws upon primary research in order to examine this intriguing case study of conflict in the mission field. The paper will also introduce questions and implications that arise from the study of this incident. The paper is comprised of two components. We will first unpack the incident, and then assess some of the larger historical and missiological implications that arise from the study, particularly within the context of world Christianity.
Contextuality and Community: Challenges for Theological Education and Ecumenical Formation
Authors: Ortega Ofelia
Published: March 2009

This article looks at some aspects of the history of ecumenical theological formation. It emphasizes the need to strive for quality theological education. This should always be ecumenical and pluralistic, link the global and the local and be founded on community‐based ecclesiastical theory. It points out the need to continue questioning the epistemological fundamentals of theology in order to ensure the continuous strengthening of the relationship between theory and practice. Another essential aspect is the relationship between mission and ecumenical theological formation and our understanding that education and ecumenical training is aimed at transforming people and communities. This means that changes to our educational institutions are indispensable. They should promote ecumenical, pluralist, inter‐disciplinary and holistic policies and practices and a commitment to a radical interpretation of the Bible that leads us to seek justice and well‐being for all people, communities and groups, and oppose any beliefs, practices and interpretation of the Bible that lead to oppression and injustice.
Contextuality and Catholicity: The Task of Orthodox Theology in Ecumenical Theological Education
Authors: Vassiliades Petros
Published: March 2009

The essay unfolds theological foundations for theological education in ecumenical perspective from Orthodox perspectives seeing it as a worldwide enterprise fundamental to the mission of the church, not in its institutional character, but in its eschatological awareness of being a foretaste of the Kingdom of God. The relation between early ecumenical optimism and enthusiasm towards the goal of the visible unity of the church and the wide application of contextuality, i.e. the recognition of the contextual character of theology as a method from the 1970s onwards is discussed. According to the Orthodox perspectives, the ecumenical movement has lost its momentum and coherence and its determination for the quest of visible unity with the predominant acceptance of contextuality as the guiding principle in ecumenical discussions and theological education. The author argues that Orthodox theology has to deepen the understanding of its own contextuality and soften the existing antithesis between contextuality and catholicity of theology and theological education. Orthodox perspectives should underline the relevance of a fundamental unity of divine revelation, as represented in the broad understanding of Christian tradition, which is for the entire created world, not only for believers and which is challenging both a potential distortion, wherein unity is identified with the maintenance of denominational loyalty, as well as all contextual expressions of Christian theology with regard to their relation to the overall goal of church unity. The paper concludes with a plea for all Orthodox theological education to be of some real service to the church in deciding to deal both with current issues (to be contextual) and not to lose sight of the past (to be oriented to catholicity and church unity), to both open up to ecumenical theological education while at the same time maintaining a strong commitment to the common church tradition.
The Future of Theological Education in Central and Eastern Europe: Challenges for Ecumenical Learning in the 21st Century1
Authors: Raiser Konrad
Published: March 2009

The article focuses on the context of Central and Eastern Europe. The introduction surveys earlier references to this context in the activities of the WCC programmes on theological education. It then characterizes the situation regarding theological education in this region, especially after the changes of 1989/90. The central section summarizes the earlier discussions on ecumenical learning, especially in the WCC, and applies the insights gained to the field of theological education. The concluding part spells out some of the consequences for the future of theological education in Central and Eastern Europe looking especially at the situation in the Orthodox churches, the Protestant minority churches and the evangelical communities.
Ethnic Studies: An Urgent Need in Theological Education in Africa
Authors: Nyende Peter
Published: March 2009

By virtue of its subject matter, theological education ought to infuse life with morals and values, thus moulding a just, moral and peaceful society such as is envisaged in God's telos for His world. And in line with its aims, theological education provides knowledge and skills to people to enable them to serve the church, together with the wider society where the church lives. A theological curriculum appropriate to its context ensures success in both these aspects of theological education. To their credit Africa's theological institutions seem to have curricula which are relevant to Africa's context. Success in sustaining the relevance of these curricula lies in continually revising the curriculum so that it does not become dated. One such urgent revision is in the offering of ethnic studies which is necessitated by the ethnic crisis in Africa. For this reason, ethnic studies in the curriculum of theological education in Africa are imperative. In the essay four ways are proposed in which ethnic studies could be included in the curriculum of theological education in Africa.
Travelling through Memory Lane: Theological Education in the World Council of Churches1
Authors: Pobee John S.
Published: March 2009

The paper highlights crucial stages in the development of the programme on Ecumenical Theological Education (ETE) in the World Council of Churches which in its earlier incarnations goes back to the Accra Conference of the International Missionary Council and the emergence of the Theological Education Fund (TEF). In referring to the Oslo world conference on theological education 1996 some key areas of the mandate of ETE and of its future perspectives are developed, including its relation to the WOCATI network and its strategic importance for the WCC.
Efficient Take‐Back Legislation
Authors: Atasu Atalay , Van Wassenhove Luk N. , Sarvary Miklos
Published: March 2009

Product and waste take‐back is becoming more regulated by countries to protect the environment. Such regulation puts an economic burden on firms, while creating fairness concerns and potentially even missing its primary target: environmental benefits. This research discusses the economic and environmental impacts of extended producer responsibility type of legislation and identifies efficiency conditions. It is shown that the right policy would (i) make producers responsible for their own waste to avoid fairness concerns and (ii) favor eco‐design producers to create stronger environmental benefits. Furthermore, the efficiency of take‐back systems is also driven by environmental classification of products, industry structure, and end‐user willingness to participate in take‐back programs.
Resource‐Constrained Project Scheduling for Timely Project Completion with Stochastic Activity Durations
Authors: Ballestín Francisco , Leus Roel
Published: March 2009

We investigate resource‐constrained project scheduling with stochastic activity durations. Various objective functions related to timely project completion are examined, as well as the correlation between these objectives. We develop a GRASP‐heuristic to produce high‐quality solutions, using so‐called descriptive sampling. The algorithm outperforms existing algorithms for expected‐makespan minimization. The distribution of the possible makespan realizations for a given scheduling policy is also studied.
Optimal Allocation of Effort to Software Maintenance: A Queuing Theory Approach
Authors: Kulkarni Vidyadhar G. , Kumar Subodha , Mookerjee Vijay S. , Sethi Suresh P.
Published: March 2009

We develop variations of the M| G|1 queue to model the process of software maintenance within organizations and use these models to compute the optimal allocation of resources to software maintenance. User requests are assumed to arrive following a Poisson process and a binomial distribution is used to model duplication of requests. We obtain expressions for expected queue lengths with an exponential server using an N‐policy for an integer N≥1. We also obtain the optimal batching size and mean service rate by minimizing the total cost consisting of the cost of the server, the cost of waiting, and the fixed cost of maintenance, if applicable.
Lack of Evidence of Pregnancy‐Induced Alloantibodies in Dogs
Authors: Blais M.‐C. , Rozanski E. A. , Hale A. S. , Shaw S. P. , Cotter S. M.
Published: March 2009

Background:It is controversial whether or not pregnant bitches become sensitized to red blood cell (RBC) antigens.

Hypothesis:Bitches do not develop alloantibodies to RBC antigens during gestation and can be used safely as blood donors.

Animals:The study group included 35 healthy female dogs with a prior history of 1 (n = 12), 2 (n = 14), or ≥ 3 (n = 9) pregnancies. The control group consisted of 15 healthy female dogs without any history of pregnancy.

Methods:All dogs were blood typed for dog erythrocyte antigens (DEA) 1.1, 1.2, 3, 4, 5, and 7 using ethylenediaminetetraacetic acid blood samples and polyclonal antisera. Antibody screening was performed with serum and canine RBC panels of known blood type. An autocontrol and direct antiglobulin test were performed to rule out the presence of autoantibodies.

Results:The only alloantibodies identified were those against DEA 7 and the prevalence of anti‐DEA 7 alloantibodies was similar in dogs with known history of pregnancy (11.4%) and in the control group (13.3%).

Conclusions and Clinical Importance:These results confirm previous studies and clinical transfusion medicine experience. Naturally occurring anti‐DEA 7 alloantibodies have been reported but their clinical relevance has not been shown. Pregnancy does not appear to sensitize dogs to RBC antigens. Consequently, dogs with prior history of pregnancy can be used safely as blood donors. Conversely, no additional pretransfusion compatibility studies would be required should these dogs themselves need to be transfused.
Effects of Aging on Inner Ear Morphology in Dogs in Relation to Brainstem Responses to Toneburst Auditory Stimuli
Authors: Ter Haar G. , De Groot J.C.M.J. , Venker‐van Haagen A.J. , Van Sluijs F.J. , Smoorenburg G.F.
Published: March 2009

Background: Age‐related hearing loss (ARHL) is the most common form of hearing loss in humans and is increasingly recognized in dogs.

Hypothesis: Cochlear lesions in dogs with ARHL are similar to those in humans and the severity of the histological changes is reflected in tone audiograms.

Animals: Ten geriatric dogs (mean age: 12.7 years) and three 9‐month‐old dogs serving as controls for histological analysis.

Methods: Observational study. Auditory thresholds were determined by recording brainstem responses (BERA) to toneburst auditory stimuli (1, 2, 4, 8, 12, 16, 24, and 32 kHz). After euthanasia and perfusion fixation, the temporal bones were harvested and processed for histological examination of the cochleas. The numbers of outer hair cells (OHCs) and inner hair cells (IHCs) were counted and the spiral ganglion cell (SGC) packing density and stria vascularis cross‐sectional area (SVCA) were determined.

Results: A combination of cochlear lesions was found in all geriatric dogs. There were significant reductions (P .001) in OHC (42%, 95% confidence interval [CI]; 24–64%) and IHC counts (21%, 95% CI; 62–90%) and SGC packing densities (323, 95% CI; 216–290) in the basal turn, SVCA was smaller in all turns. The greatest reduction in auditory sensitivity was at 8–32 kHz.

Conclusions and Clinical Importance: ARHL in this specific population of geriatric dogs was comparable histologically to the mixed type of ARHL in humans. The predominance of histological changes in the basal cochlear turn was consistent with the large threshold shifts observed in the middle‐ to high‐frequency region.
Mixed Inheritance of Equine Recurrent Airway Obstruction
Authors: Gerber V. , Baleri D. , Klukowska‐Rötzler J. , Swinburne J.E. , Dolf G.
Published: March 2009

Background:Mode of inheritance of equine recurrent airway obstruction (RAO) is unknown.

Hypothesis:Major genes are responsible for RAO.

Animals:Direct offspring of 2 RAO‐affected Warmblood stallions (n = 197; n = 163) and a representative sample of Swiss Warmbloods (n = 401).

Methods:One environmental and 4 genetic models (general, mixed inheritance, major gene, and polygene) were tested for Horse Owner Assessed Respiratory Signs Index (1–4, unaffected to severely affected) by segregation analyses of the 2 half‐sib sire families, both combined and separately, using prevalences estimated in a representative sample.

Results:In all data sets the mixed inheritance model was most likely to explain the pattern of inheritance. In all 3 datasets the mixed inheritance model did not differ significantly from the general model (P= .62,P= 1.00, andP= .27) but was always better than the major gene model (P< .01) and the polygene model (P< .01). The frequency of the deleterious allele differed considerably between the 2 sire families (P= .23 andP= .06). In both sire families the displacement was large (t= 17.52 andt= 12.24) and the heritability extremely large (h2= 1).

Conclusions and Clinical Relevance:Segregation analyses clearly reveal the presence of a major gene playing a role in RAO. In 1 family, the mode of inheritance was autosomal dominant, whereas in the other family it was autosomal recessive. Although the expression of RAO is influenced by exposure to hay, these findings suggest a strong, complex genetic background for RAO.
Plasma Atrial Natriuretic Peptide in Healthy Calves and Calves with Congenital Heart Disease
Authors: Hori Y. , Kikuchi M. , Nakagawa A. , Yonezawa T. , Miura H. , Ohnami Y.
Published: March 2009

Background: The basic and clinical implications of evaluating plasma atrial natriuretic peptide (ANP) concentration in calves are unknown.

Objective: To investigate the relationship between the plasma ANP concentration and left ventricular end‐diastolic pressure (LVEDP) in healthy calves subjected to volume overload (Study 1), and to compare the plasma ANP concentration in calves with or without heart disease (Study 2).

Animals: Six healthy calves were used in Study 1; disease calves and sick calves with (n = 9) and without congenital heart disease (CHD) (n = 9) were used in Study 2.

Methods: In Study 1, LVEDP in anesthetized calves was manipulated by IV administration of acetated Ringer's solution (rate of 100 mL/kg/h for 20 minutes) and furosemide. In Study 2, disease calves were identified by blood examination and echocardiography or pathological examination. The plasma ANP concentration was determined by a chemiluminescence enzyme immunoassay for human α‐ANP.

Results: In Study 1, preloading significantly increased the plasma ANP concentration (36 ± 20–185 ± 156, P < .01) and LVEDP (−11 ± 7–2 ± 12, P < .01) from the baseline. Furthermore, plasma ANP concentrations were strongly correlated with LVEDP (r= 0.61). In Study 2, the plasma ANP concentration was significantly higher in the calves with CHD than in the calves without heart disease (220 [67–970] versus 31 [10–86]; mean [range], P < .001).

Conclusions and Clinical Importance: Measurement of plasma ANP concentrations in calves can provide additional information useful for predicting hemodynamic abnormalities.
American Grand Strategy and the US–ROK Alliance*
Authors: Morgan Patrick M.
Published: March 2009

The US–ROK alliance is usually described and discussed in realist terms, when the proper basis for doing so for some time now has been liberalist. The alliance is lodged within a larger US–ROK community, in much the same way as other US alliances are arranged. It is also lodged within the community of democratic states that champion democratic peace theory, which essentially has come to constitute an informal but quite powerful alliance of all modern democratic states. The nature of modern liberalist alliances is such that they are very resilient, very durable, and this has helped sustain the alliance through roughly a decade of considerable strain in recent years. The alliance is now being refurbished with American global security management concerns in mind and this will require major adjustments by South Korea.
Moscow–Pyongyang Relations under Kim Jong‐il: High Hopes and Sober Reality*
Authors: Joo Seung‐Ho
Published: March 2009

With Putin's arrival in the Kremlin, a new era dawned in Moscow–Pyongyang relations. After a decade of estrangement, the two neighbors finally reached rapprochement in 2000. Political relations improved dramatically, but the momentum did not lead to noticeable expansion in military or economic cooperation. High hopes gave way to sober reality, and the two countries adjusted expectations and attitudes to one another. This article is intended to explicate the sudden rise of Moscow–Pyongyang relations shortly after Putin's inauguration and the rapid stagnation of the ties in subsequent years. Putin hoped to regain lost influence on Korean affairs by re‐establishing ties with Pyongyang. He also wanted to use joint economic projects to develop the Russian Far East and in doing so, assert Russia's position as a major power in Northeast Asia. He was not, however, willing to “pay the price.” Kim Jong‐il harbored unrealistic expectations of Russia as well. He was hopeful that Putin, as in the Soviet era, would readily grant his requests for military items, energy provision, and economic assistance, and provide them gratis. Repeated requests fell on deaf ears, and every time the same response was heard: “cash only!” Moscow and Pyongyang soon lowered their expectations toward each other. While trying to stay on Pyongyang's good side, Moscow seeks to project its image as an objective mediator and to promote multinational economic projects. Pyongyang, on the other hand, looks to Russia mostly as a counterbalance against the USA.
Quantum subgroups of a simple quantum group at roots of one
Authors: Andruskiewitsch Nicolás , Andrés García Gastón
Published: March 2009

LetGbe a connected, simply connected, simple complex algebraic group and let ϵ be a primitiveℓth root of one,ℓodd and 3∤ℓifGis of typeG2. We determine all Hopf algebra quotients of the quantized coordinate algebra 𝒪ϵ(G).
Visual Observation and Analysis of Hydrodynamic Structure of Water Jet in Application to Jet Grouting
Authors: Yoshida Hiroshi , Uemura Kennosuke , Yoshida Kenji , Kataoka Isao
Published: March 2009

Water jet is utilized in various industrial application such as cutting carious materials and soil. In particular, jet grouting for soil improvement is one of the most important application of water jet under high pressure and high liquid flow rate. Such technology is already in practical use in civil engineering. In order to improve the efficiency and performance of jet grouting, it is quite important to clarify the hydrodynamic structure of water jet under high pressure and high flow rate. However, basic researches on this subject are quite insufficient both experimentally and analytically. Water jet utilized in jet grouting is usually very high speed ( up to 500 m/s) two-phase dispersed flow. Therefore, it is quite difficult to make visual observation of such water jet using conventional optical methods. In the present work, the authors utilized high sensitive CCD camera with image intensifier of which gate speed is 10 ns. Using this optical device, the authors obtained still image of high speed water jet for the first time. Visual observation revealed that high speed water jet is composed of very fine droplets and has complicated structures such as swirl and cluster of droplets. Velocity of water jet was also measured using two consecutive images taken between 10 microsecond. Such direct measurement of jet velocity of high speed water jet has not been carried out so far. The result indicated that jet speed (droplet speed) is even very high even at the boundary of water jet. Measure water jet velocity was reasonably correlated with jet velocity at the exit of nozzle.
A Numerical Study on Fluid Force Reduction of a Square Cylinder by Flow Control
Authors: Cheng Minter , Chen B. K.
Published: March 2009

Fluid flow across a bluff body induces alternating lift and drag forces, which can produce adverse effects on many engineering applications. For a successful engineering design, it is essential to know how to suppress the fluid forces acting on the body and what is the effect of flow structure on the fluid forces. The subject of fluid forces reduction has been receiving a great deal of attention recently. A number of studies have shown that flow control is one of the effective means to suppress the forces acting on the body. However, due to numerous parameters involved, at present a detailed knowledge about how to use flow control method to suppress fluid forces is far from complete. The present study is to investigate the effects of a control cylinder on flow characteristics and fluid forces acting on the main cylinder in a two-dimensional time-dependent flow by using numerical technique. For the purpose of reducing the fluid forces acting on the main cylinder, a smaller-sized control cylinder is positioned centrally upstream. Both the main cylinder and the control cylinder are square cylinders. Steady and fluctuating fluid forces acting on the main cylinder, flow characteristics, and Strouhal numbers are investigated for different size-ratios and gap-ratios of the cylinders at a Reynolds number of 8000. Two size-ratios, 0.3 and 0.6, are used in this study. Gap-ratio is ranged from 0.5 to 3.5. It is observed that for small gap-ratios, there are two quasi-stationary vortices between the cylinders. The fluid forces acting on the main cylinder, not only the drag but also the fluctuating lift, are significantly reduced by the control cylinder. However, the fluid forces are suddenly increased when the Karman vortex street is formed between the two cylinders for larger gap-ratios. It can be concluded that in order to suppress the fluid forces acting on the main cylinder, the control cylinder must be placed at a position where the Karman vortex street would not be formed between the cylinders.
Numerical Calculation of Mass Transfer With Heterogeneous Chemical Reactions in Three-Phase Bubble Columns
Authors: Mewes Dieter , Wiemann Dierk
Published: March 2009

Bubble column reactors are used for several processes in the chemical industry, e.g. hydrogenation or oxidation reactions. At the bottom of the reactor a gaseous phase is dispersed into a continuous liquid phase with suspended particles. The resulting bubble swarm induces three-dimensional, time-dependent velocity and concentration fields, which are predicted numerically. All phases are described by an Eulerian approach. The numerical calculations of the local interfacial area density and the interphase transfer terms for mass and momentum are based on a population balance equation approach which enables an effective way to couple population balance and computational fluid dynamics. In three-phase gas-liquid-solid flow particles with diameters of 100 μm are considered as catalyst for a heterogeneous chemical reaction. The influence of particles on bubble coalescence has been investigated in order to extend an existing model for the kernel functions in the population balance equation describing bubble coalescence and dispersion. The resulting three-dimensional, time-dependent velocity and concentration fields are described and graphically presented for the hydrogenation of anthra-chinone.
Flow Characteristics of Dilute Polymer Solutions in Micro Tubes
Authors: Watanabe Keizo , Ogata Satoshi , Hirao Munehiko
Published: March 2009

Pressure drops and velocity profiles for micro tubes were investigated for the laminar flow of distilled water and dilute polymer solutions. The test micro tubes were fused silica capillaries with diameters in the range of 50.2–251.8 μm, and a value of l/d (length/diameter) of about 340. By performing pressure drop measurements, it is shown that the experimental data agree well with the Hagen-Poiseuille equation in the case of Newtonian fluids. On the other hand, the flow rate of dilute polymer solutions increases relative to that of distilled water in the low Reynolds number range. The increased flow rate ratio is a maximum of about 15% in the case of d = 251.8 μm. For the result of the micro PIV measurement, however, there are few differences between the velocity profile of distilled water and the Peo 5 ppm solution.
Hybrid Numerical-Experimental Technique of Transverse Vibration of Fluid in Tube
Authors: Ragulskis M. , Aleksa A. , Ostasevicius V. , Palevicius A.
Published: March 2009

The object of our paper is the formation of optical fringes in a time average hologram produced by vibrating fluid in axi-symmetric tube. Fluid vibrations in axi-symmetric geometry according to the first harmonics are analyzed. This problem has a practical application in the analysis of transverse vibrations of fluid in an axi-symmetric pipe. The numerical model is developed using finite element techniques in axi-symmetric geometry. Irrotational motions of ideal compressible fluid are analyzed. Finite element model of the system is based on the approximation of nodal displacements via the shape functions. Thus the field of the amplitudes of the harmonic variation of the volumetric strain is calculated exploiting conjugate approximation techniques. Obtained volumetric strains are used for the numerical construction of interference pattern of the vibrating fluid. For this purpose the Abel transform which is usually exploited in axi-symmetric problems is generalized for the problems with the periodic variation of displacements. The obtained interference patterns are used in hybrid experimental – numerical procedures and help to interpret experimental results.
Large Eddy Simulation of Turbulent Flow Laden With Binary Mixture of Particles
Authors: Chang Neng-Tsung , Hsu Chih-Hung , Chang Keh-Chin
Published: March 2009

Particle-laden turbulent channel flow at Reτ = 644, loaded with binary mixture of particles, is numerically studied using the Lagrangian particle tracking method coupled with large eddy simulation. Turbulence statistics of different particle groups are analyzed. Two particle-wall models are applied to this study with / without considering wall roughness. Taking into considerations of rough wall model, the effect of wall roughness in the computations strengthens the wall-normal particle velocity fluctuations. As a result, particles tend to move from the near-wall region to the central core region. It leads to decrement of particle accumulation in the near-wall region as compared to the case considering the smooth wall model. The wall-normal particle mixing capability is enhanced which results in the redistribution of particles in the channel. The behavior of particle motion in the turbulent channel flow should be, thus, dependent on not only the value of Stokes number but also the wall roughness level.
A Computational Study of Tomographic Reconstruction Accuracy and the Effects of Particle Blocking
Authors: Worth N. A. , Nickels T. B.
Published: March 2009

Tomographic Particle Image Velocimetry (PIV) is a promising new PIV technique which will be used to study the small scale structures of turbulence in a very large water mixing tank. To this end, an overview of the technique is presented, followed by a discussion of the technique’s fundamental principles and a number of other set-up issues. It is concluded that any residual effect resulting from the blocking of particles in the same line of sight will be small. Furthermore, during set-up, extra consideration should be given to particle selection, camera positioning, and also to the possible effects of multiple scattering.
Turbulent Drag Reduction by Hydrogen Microbubbles Made by Electrolysis
Authors: Endo Takahisa , Kato Hiroharu , Lu Xinlin
Published: March 2009

Turbulent drag reduction realized by hydrogen microbubbles was investigated experimentally. A method of generating microbubbles of 10–60μm diameter by water electrolysis was established. Experiments were performed using a water circulating tunnel. Microbubbles generated by electrolysis can achieve the same drag reduction as the injected air bubbles at a much lower void fraction. The present experimental results suggest that microbubbles produced by electrolysis are 10∼100 times more effective in terms of drag reduction than large bubbles generated by air injection. Thus, it is considered that the diameters of microbubbles play an important role in drag reduction.
A Disperse-Phase Dynamic SGS Coupling Model for Particle-Laden Turbulent Flows
Authors: Lei Kangbin , Kase Kiwamu , Oshima Nobuyuki , Kobayashi Toshio
Published: March 2009

In order to study the effects of turbulence sub-grid-scale (SGS) fluctuation on particle Lagrangian motion in turbulent flows, a dynamic random walk (DRW) SGS coupling model based on an Eulerian-Lagrangian approach was developed. The advantage of the new model is that the Gaussian statistical distribution and local isotropic properties of turbulence SGS fluctuation can be parameterized by Germano’s (1991) Eulerian dynamic procedure. Using the present model, large eddy simulation (LES) was performed for downward channel flow at a Reynolds number of 180, as in the direct numerical simulation (DNS) done by Rouson & Eaton in 1997. Through a comparing of the statistical properties of particle diffusion with DNS, the capabilities and limitations of the present DRW SGS model were verified. Moreover, it was found that turbulence SGS fluctuation was strongly associated with particle motion, because preferred particles were affected by the preferred length scale of the eddy structure around. It was also found that turbulence SGS fluctuations are indispensable in calculating particles’ Lagrangian trajectories in LES even when the particle Stokes number is high.
Velocity Profile Measurements of Two-Phase Flow in Rectangular Channel Using Ultrasonic Time-Domain Correlation Method
Authors: Hayashida Takuya , Murakawa Hideki , Kikura Hiroshige , Aritomi Masanori , Mori Michitsugu
Published: March 2009

Velocity measurement using ultrasound has attracted much attention in engineering fields and medical science field. Especially, Ultrasonic velocity profile monitor (UVP) has been in the spotlight in engineering fields, because of its many diagnostic advantages. The major advantage is that UVP can obtain instantaneous velocity distributions on beam line by measuring Doppler shift frequencies of echo signals. And UVP is applicable to existing pipes, because it is non-contact measurement technique. In recent years, various studies about UVP have been done, and UVP has already been put to practical use in engineering plants. The authors especially focused on two-phase flow measurement using ultrasound. Previously, we developed a way to measure bubbly flow using UVP. By this method, we are able to separate liquid information from bubbles information to some degrees. However, when the bubble number density is low, a problem occurs. Because the effect of liquid information is strong under that condition. From this fact, we applied the ultrasound time domain correlation method (UTDC) to two-phase flow measurement. This method is our original technique to measure the velocity distribution. It is based on the cross-correlation between two consecutive echoes of ultrasonic pulses. With this method, we can separate liquid information from bubble information even when the bubble number density is low, because reflected signals depend on the size of reflectors and frequency of ultrasound. In this study, the authors applied the UTDC to two-phase flow measurements in rectangular channel using a multi-wave ultrasonic transducer (TDX). The multi-wave TDX has two kinds of basic frequencies. One is 2MHz for the velocity of rising bubbles and the other is 8MHz for the liquid velocity. So it enables us to measure the velocity of the liquid and that of bubbles at the same point and time. The 2MHz ultrasonic element of TDX has 10mm diameter and the 8MHz ultrasonic element has 3mm diameter.
Dynamic Characteristics of Flow Separation From a Low Reynolds Number Airfoil
Authors: Morse Daniel R. , Liburdy James A.
Published: March 2009

This study examines the generation of large scale vortices caused by flow separation from a flat wing at various angles of attack. Time-resolved particle image velocimetry is used to determine the evolution and convective characteristics of the large scale structures. A rectangular airfoil with aspect ratio of 0.5 is used and data are collected at a Reynolds number of 23,500, for angles of attack from 0° to 20°. Data consists of two dimensional velocity fields obtained at 500 Hz located at the airfoil centerline. The region of interest is near the separation point but fields of view extend over approximately one half of the chord length from the leading edge to document the downstream progression of the large scale vortical flow elements. The velocity data were processed to identify the vorticity field dynamics in terms of the Kelvin-Helmholtz instability occurring near the leading edge. The vortical structures are identified using vortex detection based on local circulation. The convective nature of the vortex elements are shown to consist of merging, stalling and convecting, with convective velocities on the order of 20% of the freestream velocity with an associated Stouhal number based on chord length and freestream velocity of approximately 1.0.
Two-Dimensional Low Mach Number Heat Transfer Simulation of Turbine Blade Leading-Edge Model
Authors: Litzler Jeff , Mishra Suman , Ghia Urmila , Ghia Karman , Ou Shichuan
Published: March 2009

A subsonic, viscous, laminar flow and heat transfer is simulated in the present study over a two-dimensional, isothermal, bluff-body representing a turbine blade leading-edge. The purpose of this simulation is to predict local Frossling number; to determine the accuracy of the predictions as compared to experimental results, and to compare the results from two flow solvers, Fluent and Cobalt. The geometry consists of a half-cylinder of diameter 8.89 cm and a flat after-body, and represents to the model used in the corresponding experimental investigations. The simulations are performed on a multi-block, hybrid grid topology developed using GridGen as the grid generation software. Researchers have earlier investigated heat transfer over a similar model. Utilizing computational modeling techniques, a representative simulation of the physical flow mechanism enables further investigation into the characteristics of the flow. The boundary conditions for the problem are identified as no-slip and isothermal on the bluff body, and uniform velocity is assumed at the inlet. Results are presented in the form of the Frossling number, defined as the Nusselt number divided by the square root of Reynolds number. The results are compared with published experimental data for the experimental geometry described earlier, and the cross-flow-cylinder, to assess the validity of the numerical approaches.
CFD Validation of Gas Injection Into Stagnant Water
Authors: Ibrahim Ashraf , Felde David , Riemer Bernard , Wendel Mark
Published: March 2009

Investigations in the area of two-phase flow at the Oak Ridge National Laboratory’s (ORNL) Spallation Neutron Source (SNS) facility are progressing. It is expected that the target vessel lifetime could be extended by introducing gas into the liquid mercury target. As part of an effort to validate the two-phase computational fluid dynamics (CFD) model, simulations and experiments of gas injection in stagnant water have been completed. The volume of fluid (VOF) method as implemented in ANSYS-CFX was used to simulate the unsteady two-phase flow of gas injection into stagnant water. Flow visualization data were obtained with a high-speed camera for the comparison of predicted and measured bubble sizes and shapes at various stages of the bubble growth, detachment, and gravitational rise. The CFD model is validated with these experimental measurements at different gas flow rates. The acoustic waves emitted at the time of detachment and during subsequent oscillations of the bubble were recorded with a microphone. The acoustic signature aspect of this validation is particularly interesting since it has applicability to the injection of gas into liquid mercury, which is opaque.
Momentum and Heat Transport in a Finite-Length-Cylinder Wake
Authors: Wang Hanfeng , Zhou Yu
Published: March 2009

This paper reports an experimental study of the turbulent momentum and heat transport in the wake of a wall-mounted finite-length square cylinder, with the aspect ratio R (= H/d, where H and d are cylinder height and width) chosen to be 3, 5 and 7. All tested cylinder was slightly heated, the temperature difference is about 1°C, so that the temperature can be considered as passive scalar. A moveable three-wire probe (a combination of an X-wire and a clod wire) was used to measure the velocity and temperature fluctuation, at a Reynolds number of 7,300 (based on d and free-stream velocity, U∞). Measurements were performed at a downstream distance of 10d and different spanwise locations to investigate the effects of R on momentum and heat transport. Measurements were also conducted in a two-dimensional (2D) square cylinder wake to apply a benchmark. It is found that the distributions of time-averaged velocity and temperature are modified in different manners at various spanwise stations in a finite-length cylinder wake. Near the height of free end, time-averaged velocity is increased near the centerline by downwash flow, which entrains high speed fluid into the wake; whereas the mean temperature distribution is not changed significantly. At near the ground plate, the distribution of mean velocity is flattened; while the distribution of mean temperature is concentrated near the centerline. This suggests a more effective transport of momentum than heat near ground plate. Reynolds stresses, temperature variance and heat flux are impaired relative to those of 2D cylinder wake, especially for lateral normal stress. The effects of both downwash flow and boundary layer on the distributions of turbulent statistics become more obvious as R increases from 3 to 7.
Control of Natural Convection in a Differentially Heated Cavity With a Thermal Perturbation at the Hot Wall
Authors: Skurtys Olivier , Penot Francois
Published: March 2009

An experimental study of flows and heat transfer enhancements in an air-filled differentially heated cavity of vertical aspect ratio 4, is presented. The control mechanism employed in the present research consists in thermal disturbances produced by a thin tube located at the bottom of the hot wall. The effects of amplitude and of temperature frequency signals are investigated for two Rayleigh numbers. For the first value, just above the first bifurcation, the flow is periodical. For the second, the flow is turbulent. The results show details of flow structures, such as the spatial distribution of the local mean and fluctuating velocity, the evolution of the global and local Nusselt numbers. A more complex behaviour of the flow is observed than was anticipated.