bluuebunny/crossref_metadata_2025 huggingface dataset:
Chronology and Geochemistry of Mesozoic Volcanic Rocks in the Linjiang Area, Jilin Province and their Tectonic Implications
Authors: YU Yang , XU Wenliang , PEI Fuping , YANG Debin , ZHAO Quanguo
Published: April 2009

Zircon U‐Pb ages and geochemical analytical results are presented for the volcanic rocks of the Naozhigou, Ergulazi, and Sidaogou Formations in the Linjiang area, southeastern Jilin Province to constrain the nature of magma source and their tectonic settings. The Naozhigou Formation is composed mainly of andesite and rhyolite and its weighted mean 206Pb/238U age for 13 zircon grains is 222±1 Ma. The Ergulazi Formation consists of basaltic andesite, basaltic trachyandesite, and andesite, and six grains give a weighted mean 206Pb/Z38U age of 131±4 Ma. The Sidaogou Formation consists mainly of trachyandesite and rhyolite, and six zircon grains yield a weighted mean 206Pb/238U age of 113±4 Ma. The volcanic rocks have SiO2= 60.24%–77.46%, MgO = 0.36%–1.29% (Mg#= 0.32–0.40) for the Naozhigou Formation, SiO2= 51.60%–59.32%, MgO = 3.70%–5.54% (Mg#= 0.50–0.60) for the Ergulazi Formation, and SiO2= 58.28%–76.32%, MgO = 0.07%–1.20% (Mg#= 0.14–0.46) for the Sidaogou Formation. The trace element analytical results indicate that these volcanic rocks are characterized by enrichment in light rare earth elements (LREEs) and large ion lithophile elements (LILEs), relative depletion in heavy rare earth elements (HREEs) and high field strength elements (HFSEs, Nb, Ta, and Ti), and negative Eu anomalies. Compared with the primitive mantle, the Mesozoic volcanic rocks in the Linjiang area have relatively high initial 87Sr/86Sr ratios (0.7053–0.7083) and low ɛNd(t) values (−8.38 to –2.43), and display an EMU trend. The late Triassic magma for the Naozhigou Formation could be derived from partial melting of a newly accretional crust with the minor involvement of the North China Craton basement and formed under an extensional environment after the collision of the Yangtze Craton and the North China Craton. The Early Cretaceous volcanic rocks for the Ergulazi and Sidaogou Formations could be formed under the tectonic setting of an active continental margin related to the westward subduction of the Izanagi plate.
A New Non‐Pterodactyloid Pterosaur from Qinglong County, Hebei Province of China
Authors: LÜ Junchang
Published: April 2009

A new basal non‐pterodactyloid pterosaur,Changchengopterus panigen. et sp. nov., is erected, on the basis of a nearly complete postcranial skeleton. The new taxon is distinguished by relatively short extensions of the prezygapophyses, postzygapophyses and haemal arches of the caudal vertebrae; a humerus that has a subtriangular deltopectoral crest; limb elements that decrease in length in the following order: ulna> wing‐phalange 2 > wing‐phalange 3 = wing‐phalange 1>humerus >tibia>femur>wing‐metacarpal. Phylogenetic analysis suggests thatChangchengopterusis a basal member of rhamphorhynchoids, and more closely related toDorygnathusthan to other rhamphorhychoids. The geological age of theChangchengopterus‐bearing sediments is no latter than the end of the Late Jurassic and it is possible Middle Jurassic.
Special Xenoliths in an Aegirine‐Augite Syenite Porphyry in Liuhe, Yunnan, China: Discovery and Implications
Authors: LIU Xianfan , SONG Xiangfeng , LU Qiuxia , TAO Zhuan , LONG Xunrong , ZHAO Fufeng
Published: April 2009

Three special types of xenoliths have recently been found in an aegirine‐augite syenite porphyry in Liuhe, Yunnan, China. Petrographical, petrochemical, electron microprobe, and scanning electron microscopy studies indicate that pure calcite xenocrysts and quartz‐bearing topaz pegmatite xenoliths result from the degassing of mantle fluids during their migration, and that black microcrystalline iron‐rich silicate‐melt xenoliths are the product of the extraction of mantle fluids accompanying degassing and are composed dominantly of quartz, chlorite, and iron‐rich columnar and sheet silicate minerals with characteristic minerals, such as native iron, apatite, and zircon. According to the bulk‐rock chemical and mineral compositions and crystallization states, the microcrystalline melt xenoliths are not the product of conventional magmatism, and especially the existence of native iron further proves that the xenoliths were mantle fluid materials under reduction or anoxic conditions. The study of the special xenoliths furnishes an important deep‐process geochemical background of polymetallic mineralization in different rocks and strata in the study area.
Red Bucket for the Red Cordial, Green Bucket for the Green Cordial: On the Logic and Logistics of Warlpiri Birthday Parties1
Authors: Musharbash Yasmine
Published: April 2009

Birthday parties are a relatively new occurrence at Yuendumu, a Warlpiri settlement in central Australia. By focusing on the food prepared and consumed at these parties, I examine the ritualised Warlpiri and non‐Warlpiri elements of these events, with a particular view to Warlpiri women's creativity in shaping and re‐shaping them. I contrast birthday party food from everyday staple foods and so‐called ‘bush tucker’, and analyse these different food types in regard to generational differentiation. Lastly, the role of the anthropologist in shaping birthday parties as well as in writing about them is scrutinised.
The Reliable Beauty of Aroma: Staples of Food and Cultural Production among Italian‐Australians1
Authors: James Roberta
Published: April 2009

This paper takes an ethnographic journey into Italian‐Australian cultural production through an examination of the Italian term for both the flavour and taste of herbs, aroma. Here, I explore the ways in which staple foods and their commensalities engender staple cultural production without necessarily overdetermining the culture produced. Taking the material indeterminacy of culture as a theoretical starting point, I argue that this is the reliable beauty of aroma as well as is its capacity to capture the realities of culture as lived experience. When culture is approached from this direction, stature is returned to ethnographic subjects as people living lives rather than as automatons of cultural form. From this vantage, a theoretical preoccupation with order and structure may be seen to hinder rather than enhance an apprehension of ethnographic fact.
Transitions in Taste in Vietnam and the Diaspora
Authors: Thomas Mandy
Published: April 2009

This paper argues that food and styles of eating have become the predominant markers of social change for the Vietnamese in both Vietnam and in the diaspora. In post‐socialist Vietnam the transition to a market economy has allowed for a huge growth in the number of restaurants and cafés, and in the north, a return to an earlier style of cooking. The intense interest and emphasis on food as embodied pleasure has meant that it has come to stand for the transition away from a heavily state‐controlled economy. The new configurations of family and friendship are being framed by newly available ways of ‘eating out’, which are both a means of social display and distinction as well as an indicator of the tensions between reform and festivity within an authoritarian nation‐state struggling to define itself in a globalising world.

At the same time as food in Vietnam is undergoing rapid transformation so too has the Vietnamese diaspora generationally changed its eating patterns. Although there has been a focus in the literature on food in the diaspora that emphasises the nostalgic and recuperative elements of ‘migrant food’, I argue that food is the prime mechanism of intercultural engagement for each diasporic generation. For older Vietnamese, Vietnamese restaurants and barbecues have been the sites of interplay between cultural ‘tradition’ and innovation, and between Australianness and Vietnameseness, and these interstitial places continue to be important for younger Vietnamese. Within this established framework of cross‐cultural interaction, for Vietnamese youth, the social settings of ‘ethnic food’, eaten at home and shared with family, have been grafted onto a sociality of eating fast food. This melding together of both invention and convention, of transgression and ordinariness provides the background against which young people from migrant backgrounds are reinvigorating the social spaces of food consumption and in the process both re‐enchanting and destabilising the notion of migrant food.
Love Food: Exchange and Sustenance in the Cook Islands Diaspora
Authors: Alexeyeff Kalissa
Published: April 2009

This paper analyses the dynamics of food exchange among Cook Islanders. The majority of Cook Islanders live abroad (primarily in New Zealand and Australia), familial and community relationships are maintained by frequent visits to and from the Cook Islands. For many Cook Islanders, the difference between home and abroad is signified through food. Its lack in New Zealand is contrasted with the bounty of home, bounty of food, and the bounty of sustaining caring relationships. As a result, when Cook Islanders from home visit family abroad, they take large quantities of local food with them. This paper explores the affective materiality of food that travels between Cook Islands
Risk Reduction of Jet Engine Product Development Using Technology Readiness Metrics
Authors: Niemeyer Jonathan K. , Whitney Daniel E.
Published: April 2009

This paper looks at the product development process as an exercise in risk reduction and performs a critical analysis of how gas turbine engine manufacturers weigh the competing risks associated with on-time delivery, product quality, and development costs. Three frameworks are used to focus the analysis: • Iteration by using multiple attempts to converge to an acceptable solution. • Maintaining options in development, and delaying convergence to a single design. • Improving the organization’s predictive capability prior to committing to a particular set of performance goals, designs, or technologies for a product. This is explored from the perspective of “technology readiness”. For six gas turbine engine development programs, case studies were performed to assess the effectiveness of the product development process by measuring how well the engine met its guaranteed level of fuel consumption. For each development program, performance against guarantees was compared against technology readiness levels (TRL) at program launch when performance was guaranteed by contract to customers, and against the degree of flexibility provided to designers to react once performance shortfalls were known. Decomposition of the engine system into sub-systems was necessary to specifically define TRL, parallel efforts, and iteration. Risk strategies were compared in light of the time sensitivity of the quality of information, the cost of engineering changes, contractual penalties, and lead times associated with implementing improvements.
A Computational Approach to Conceptual Design
Authors: Strawbridge Zeke , McAdams Daniel A. , Stone Robert B.
Published: April 2009

Design research has generated many computational tools to aid the designer over the years. Most of these tools are focused on either the preliminary steps of customer need gathering or the concluding steps of embodiment or detail design. The conceptual design phase has seen fewer computational tools even though well known methods are available such as brainstorming, intrinsic and extrinsic searches and morphological analysis. In this paper a generalized computational conceptual design tool is presented to aid designers at the conceptual design stage. It relies on storing and reusing existing design knowledge to create new concept variants. Concept variants are computed using matrix manipulations, essentially creating a mathematical morphological matrix. The concept generator produces quick concepts that can be used for concept selection or as a basis for generating additional concept variants through non-computational, creative techniques.
New Advances in the Functional Modeling of Electro-Mechanical Components
Authors: Campbell Matthew I. , Limaye Advait
Published: April 2009

This paper presents some key extensions to a representation for electromechanical components that is sufficiently detailed enough to provide for the automated construction of new design configurations. The extensions, shown here, build upon a representation that is both formal and implemented, and can handle the interactions between components even if such interactions represent only partial configurations. The results of these new additions elucidate the power and flexibility of this functional representation for electromechanical components. The method can be used as an interactive tool to allow an engineering designer to explore new design concepts or can be combined with additional software tools to achieve a computational design synthesis approach to topological design problems. The inclusion of function sharing, component layout, and qualitative dynamics achieve a closer approach to how the human mind represents components.
Planning and Scheduling Based on an Explicit Representation of the State of the Design
Authors: Melo Andre´s Felipe , Clarkson P. John
Published: April 2009

This paper describes a computational model that provides planning information useful for scheduling the design process. The model aims to reduce uncertainty in the design process and with it the risk of rework. The view is taken that planning is concerned with choosing between alternative actions and action sequences, but not with resource allocation. The planning model is based on an explicit representation of the state of the design process, the definition of the design capabilities as a pool of tasks, and on the generation and selection of plans by evaluating their reliability. Classical decision theory is used for evaluating the plans: a state-action net is built and analyzed as a Markov decision process. The model produces plans based on qualified task dependencies. These plans can be used as a basis for manual and automated scheduling. In an example industrial case study, a reduction of over 30% in the expected rework was predicted.
Modelling Design Interpretation as Interaction of Problem Framing and Problem Solving
Authors: Dzbor Martin , Zdrahal Zdenek
Published: April 2009

Design is usually considered a reflective and ill-structured process. This paper presents a new, sequential model of such a process. Design is modelled as an interplay of two conceptually distinct activities — an explicit specification of a problem and a solution to it. The approach is novel in defining an operation of framing, i.e. interpretation of a given problem using certain conceptual commitments. So far, the interpretation of design problems enjoyed less rigorous investigation as the aspect of problem solving in both design theory and methodology. In this paper we model three reasoning patterns for (re-)interpreting design problems. These patterns are complemented by an operational framework based on abstracted similarity, and illustrated by extracts from experimental studies.
An Evaluation Method for Inconsistency of the AHP Judgment Matrix
Authors: Huang Yuan Mao , Ho Hsin-Ni
Published: April 2009

Applications of the analytic hierarchy process have been widespread in the field of decision-making for decades. In this process, decision-makers perform pairwise comparisons to form a judgment matrix, and its principal eigenvector is used to represent the priorities. Thus it is important to evaluate the degree of inconsistency in a judgment matrix to ensure the principal eigenvector reflects the true priorities among the alternatives. This study proposes the I3 circuit method, which is based on the graph theory, with a critical inconsistent index value of 3.75 to judge and evaluate consistency or the degree of inconsistency for judgment matrices. In addition, it can also spot the matrix entries that create the most inconsistency. With these advantages of the proposed method, decision-makers can easily evaluate the pairwise comparisons of a matrix and revise some entries of the matrix toward consistency if needed.
A Method of Form Selection for Large Scale Structures
Authors: Pasini Damiano , Burgess S. C. , Smith D. J.
Published: April 2009

This paper presents a new method for modelling the efficiency of large-scale structural forms. Parametric equations, which include all design parameters and also the effect of buckling, are developed. Shape transformers, envelope efficiency parameter and scaling factor are introduced to describe the geometrical properties of cross-sections and to allow interaction between form and cross-sectional shape selection. Design charts provide insight and understanding and assist the selection of different structural concepts at the preliminary stage of design.
A New Functional Representation Scheme for Conceptual Modeling of Mechatronic Systems
Authors: Chen Li , Jayaram Murali , Xi Jeff F.
Published: April 2009

Traditional mechatronic system designs focus on generation of design parameters, simulation of performance and behavior, but overlook functional design. Obtaining the best possible design parameters requires the representation and analysis of the functional space. In particular, representing a mechatronic system needs to account for various functions, flows, semantics and relationships that exist in each discipline. To this end, a new functional representation scheme for conceptual modeling of mechatronic systems is presented. The functional representation scheme standardizes and characterizes functional design in view of functional requirements generation. The proposed scheme incorporates the essential features of the disciplines of a mechatronic system through its functions, flows and relationships. This scheme is illustrated through the example of a parallel robot.
Methods and Tools for Requirements Engineering of Made-to-Order Mechanical Products
Authors: Effendi Iwan , Henson Brian , Agouridas Vassilis , de Pennington Alan
Published: April 2009

This paper reviews tools and methods for requirements engineering and assesses their applicability to requirements management of a made-to-order mechanical product. One method, the use of a formal specification modeling language, is used to model the evolving specification of a mechanical system during embodiment and detail design. The model of the product specification is then evaluated against the following criteria: verifiability; correctness; understandability; consistency; ability to represent different levels of detail; modifiability; traceability; ambiguity; and annotability. The suitability of using specification languages to represent mechanical product specifications is discussed.
Modularization of Design Knowledge as a Basis for a High Quality Competence Pool in Product Development
Authors: Berger Benjamin , Birkhofer Herbert
Published: April 2009

Contents of product development knowledge have to be available in a broad range and rank high in quality for teaching, learning and application. Individuality in presenting and high flexibility in use and arrangement are requested. Furthermore, the collaboration of different authors with different background is aimed to create a common competence pool in the range of product development. Therefore an approach to modularization, filing and accessing of various contents of product development knowledge will be applied. Contents of product development knowledge are modularized based on three levels — elements, modules and containers — and they are linked and integrated into the competence pool. Considering the requirements of different users, individual and specific documents can be created out of the modularized contents, e.g., material for a specific lecture. Appropriate modularization is considered as a basis for higher quality and improvement of communication and collaboration.
Quantifying Certainty in Design Decisions: Examining AHP
Authors: Scott Michael J.
Published: April 2009

Quantification of stochastic uncertainty through confidence intervals when probability distributions are known is well-understood. There is considerable uncertainty in design decision support, however, for which probability distributions are unknown. The confidence interval formulation does not apply to these situations. The Analytic Hierarchy Process, or AHP, is an example of a tool with wide-spread industry application but questionable mathematical foundations. It is recognized by responsible practitioners that AHP should not be used as an optimization tool, but as a means of clarifying group attitudes. This raises the question, how differently must two alternatives be ranked by AHP to instill confidence that one is truly better than the other? In practice, this question is always answered using intuition. This paper examines and proposes the quantification of sources of uncertainty in the Analytic Hierarchy Process, and offers an answer to the question posed above. This study is the first step of a larger effort to quantify uncertainties in decision support in engineering design.
Utilization of Dependency Structure Matrix Analysis to Assess Complex Project Designs
Authors: Brady Timothy K.
Published: April 2009

This paper describes a framework for evaluating the long-term effect of early project implementation decisions. Early decisions, such as establishing the system architecture and selecting technology of particular maturity, can have lasting impact throughout the project development process and during the project’s operations phase. A systems engineering analysis framework using two different extensions of dependency structure matrix (DSM) analysis was developed to provide a comprehensive system view of the project architecture and the technology choices. An “interface DSM” mapped the dependence of components on one another and identified the impact of component criticality on the project’s operations. A “technology risk DSM” included a component technology risk factor to help identify the patterns of system level risk. This analytical framework can be used to expand the design and management teams’ holistic view of the project, which can be used to enhance project implementation decision-making. The analytical framework described in this paper was applied to two spacecraft projects, which served as case studies. Analytical observations were compared to post-project lessons learned to develop a general understanding of the relationship between the critical elements of each project’s structure and the successful implementation approach for each case.
Flexible Multistage Bayesian Models for Use in Conceptual Design
Authors: Pacheco Jorge E. , Amon Cristina H. , Finger Susan
Published: April 2009

During conceptual design, designers need tools to help improve design decisions and reduce design times. We are working to develop techniques to create Bayesian surrogate models that respond to designers’ needs during conceptual stages of the design process. Bayesian surrogate models give analytical form to the overall performance of a system and can evolve along with the design. Bayesian surrogate models provide a mathematically rigorous framework in which computational models can be updated based on previous outcomes. In this paper, we present techniques that allow the addition or suppression of parameters without discarding previously obtained information. We also present a case study that illustrates how a surrogate model is constructed in stages when parameters are added or suppressed during the design process. Visualization tools, such as plots of the main effects of parameters, can be derived from surrogate models. These tools can be used to provide knowledge about the parameters that influence the design. Finally, a design problem is used to illustrate how Bayesian surrogate models can inform the designer about tradeoffs that would not be apparent from simulation data alone.
Creative Stimulation in Conceptual Design
Authors: Benami Oren , Jin Yan
Published: April 2009

Conceptual design is a process of creating functions, forms and behaviors. Although cognitive processes are utilized in the development of new ideas, conventional methodologies do not take human cognition into account. However, it is conceivable that if one could determine how cognitive processes are stimulated, then more effective conceptual design methods could be developed. In this paper, we develop a Cognitive Model of Creative Conceptual Design to capture the relationship between the properties that stimulate cognitive processes and the design operations that facilitate cognitive processes. Through cognitive modeling, protocol analysis, and cognitive experiments, this research showed that designers exhibit patterns of creative design behavior, and that these patterns can be captured and instilled into the design process, to promote creativity.
Characterising Modular Architectures
Authors: Sharman David M. , Yassine Ali A. , Carlile Paul
Published: April 2009

In this paper, we introduce the basic syntax and semantics for scrutinising DSMs in order to characterise the architecture of a complex system. Using this language, we then describe the process issues faced by clustering algorithms and use them to arrive at quantifiable signature measures for describing architectural types spanning the modular-integrated continuum. This language is demonstrated using a sequence of illustrative cartoons that are woven between the analysis of a more complex architecture of an industrial gas turbine.
Converging in Problem Formulation: A Different Path in Design
Authors: Cavallucci Denis , Lutz Philippe , Kucharavy Dmitry
Published: April 2009

The efficiency of the design process in companies today is largely dependent on the skills of individual members of project teams, the capacity of the software available on the market and any assistance provided by the tools and methods found scattered around the industrial world. Within this context, there have been myriad attempts to optimize the different stages in the design process by using computerization, but a growing proportion of current research work on design tends to agree that the crucial point in the act of designing lies in the phase where inventive ideas are sought and that without such ideas being generated, there is no successful future for the product. In the framework of a large number of research activities it has been proven that the TRIZ (the Russian acronym of Theory of Inventive Problem Solving) contribution to the science of design has a promising potential [1–2–3–4]. On the other hand, the added value and spectrum of problem typology where TRIZ could help remains unclear for most researchers for various reasons. Originally, since the theory has penetrated the so-called occidental world, every individual took from TRIZ what he thought was right according to his own knowledge about design, problem solving process, creativity or needs forgetting that 95% of scientific literature about TRIZ’s fundamentals was written either in Cyrillic or in unpublished manuscripts. In most cases, theses multitudes of uses did not see that the original idea of TRIZ was to formulate a theory as strong basement for building methods and tools to satisfy designers expectations. This fact led nowadays TRIZ’s image to fuzziness since available literature on the subject only presents case studies and uses of tools (mostly the matrix) although TRIZ’s scope is much wider. To avoid further aggravation of this fact, this paper aims at presenting the first axiom describing TRIZ’s objectives as a basement for our research activities. Two methodological approaches are then presented : the “trial and error” type approach, which is still very much in use everywhere in industry and which aims to explore an area of solution-seeking, following a structural approach or not, through a series of attempts, which often end up in failure. The second approach is the “convergent” approach proposed by the TRIZ body of knowledge and developed as a contribution to design activity’s efficiency in our research center. This approach aims at limiting the sphere of research during a larger and longer problem statement stage to converge towards a small number of solutions in opposition to traditional approaches which consists in generating a large amount of ideas and select the best suitable ones to be implemented. A case study on the internal ventilation of a car will also be presented to illustrate the quality of the results that could be obtained when applying this convergent approach.
A Clock Grammar: The Use of a Parallel Grammar in Performance-Based Mechanical Synthesis
Authors: Starling Alex C. , Shea Kristina
Published: April 2009

Effective methods of computational synthesis for mechanical systems must represent both function and structure in order to generate physical designs with desired behaviors. To this aim, a parallel grammar for mechanical synthesis was developed based on a Function-Behavior-Structure design model. This parallel grammar was implemented for the domain of mechanical clocks and watches in order to demonstrate the flexibility and strengths of the approach. Designs were produced using a fully parametric parts library. Incorporating performance considerations, generate-and-test methods were then used to produce clock designs that satisfy different sets of spatial constraints to demonstrate the potential of the method for general mechanical synthesis problems.
A Model of Learning in Design
Authors: Sim Siang Kok , Duffy Alex H. B.
Published: April 2009

Learning in design is a phenomenon observed in design practice. Yet there is no comprehensive model or theory that explains the phenomenon and serves as a basis upon which design support systems are developed. This paper describes the development of a novel model of learning in design, LinD, that seeks to formalise the nature of learning in design. The model features formalisms for describing the cognitive activities of design and learning and three links that explain the interactions between these activities; these links being the epistemic, teleological and temporal links.
Designers in Organisations
Authors: Wognum P. M.
Published: April 2009

Design processes in current industrial contexts require integration between different disciplines and functions, not only within an organisation but also across organisational and even national borders. Many barriers to integration can be observed, however, in multi-disciplinary and multifunctional design projects. One of these barriers is the lack of organisational, management, and social knowledge and skills, on the level of team members as well as on the level of project management. To achieve a sufficient level of integration technical knowledge and skills are necessary but not sufficient. Organisational, management, and social skills are necessary too. In our research on organisation and management of business processes we have found that this last category of knowledge needs improvement for the largest part of design team members and managers. As designers are professionals who have been employed because of their knowledge and skills, gained through prior academic or professional education, the question can be asked to what extent organisational, management, and social knowledge is included in this education. One way to answer this question is by studying the knowledge and skills deemed important for performing design tasks. An important source of this knowledge can be found in journal articles in the area of engineering design. The authors of these articles are in most cases also the ones transferring this knowledge to future designers. In this paper, a study of 94 recently published journals articles is described, which reveals, that organisational, management, and social skills are not yet a major focus of attention. In particular the number of empirical studies on the organisational, social, and managerial behaviour of designers in practical contexts is scarce in the engineering research community. These results will be confronted with results from management and social sciences research. We argue that the gap between these two fields of research needs to be bridged to better prepare designers for their task in current industrial contexts.
Comparing Function and Affordance as Bases for Design
Authors: Maier Jonathan R. A. , Fadel Georges M.
Published: April 2009

A major objective of engineering design research has been the establishment of design science. Toward this end, there is a need to establish the fundamental concepts that should underlie the basic theories comprising a science of design. The purpose of this paper is to compare two concepts that have been proposed as bases for design—the concept of function and the concept of affordance. After exploring the history-to-date and current application of these concepts of design, they are then compared. In many respects, affordance and function complement each other, such as in describing artifacts and combining existing design methods. However, in other respects, these two concepts differ greatly, as in their theoretical underpinnings, degree of complexity, and acceptance. The issue of the degree of complexity entailed in the two concepts of affordance and function is given particular attention as it of special importance in understanding the differences between affordance and function. It is concluded that the concept of function, because it describes a simple input / output relationship, is appropriate to use in the context of the transformative type aspects of the design of artifacts. However, when the larger complex context of design is considered, including not only the artifact, but the designer and user, and all the interactions in between, the concept of affordance is appropriate because it describe complex relationships. Hence function is an appropriate basis for the design of the transformative technical character of an artifact. However affordance is an appropriate basis for the design activity in general.
A Visualistic Approach in Aerodynamics
Authors: Marineau Eric , Reggio Marcelo , Tre´panier J.-Y. , Ozell Benoit
Published: April 2009

This study stresses the power of the visual communication language in engineering education and design. The work explores the potential of virtual learning tools aimed to create a new dimension for the study and the understanding of aerodynamics in higher education. For an aerodynamic wing, an hyperspace is defined by selecting geometric and flow variables. It is proposed to study the relation among these variables and their impact on the aerodynamic performance by defining various set and assemblies of three-dimensional subspaces. These spaces are then visualized in the 3D CAVE immersive room opening thus novel paths for the undestanding of the performance of wing aerodynamics with flow and geometric variation. The particular case of airplane wings is presented.
Evaluation of Ring Gear Tooth Stress
Authors: Duong Loc , McCune Michael , Kazerounian Kazem
Published: April 2009

To optimize the operating speeds of the low spool of a gas turbine engine together with the overall transmitted horsepower to weight ratio, an epicyclic gear train is used to transmit power from the turbine section to the propeller shaft (as in PWC PT6 engine) or to the fan shaft (as in Honeywell TFE-731 engine). In order to achieve an optimum design in view of structural integrity, the stress characteristics of each component of the epicyclic gear train needs to be optimized. In general, the external gear mesh (as in the sun and planet mesh), needs a back up rim to tooth thickness ratio of not less than 1.2. However, this is not always the case for internal gear mesh such as the ring gear. The objective of this paper is to present analytical results on the stress behavior of the ring gear under different loading conditions. Three dimensional finite element method is employed to study the internal tooth fillet stress under the effects of fillet radius, gear rim thickness, pressure angle and helix angle. This study is the first part of a work aiming to determine the failure mode of the ring gear and leading to design optimization of epicyclic systems.
Collaborative Engineering in Integrated Aircraft Power System Design
Authors: Bayt Robert L. , Sahm Michael K. , Lents Charles E.
Published: April 2009

Integrated aircraft power system design can provide for performance increases, weight reductions, and cost reductions by exploiting synergies and opportunities for functional integration between systems. A method for bringing together discipline expertise into a common environment for defining system specifications and interfaces that exploit these synergies is presented here. The goal is to create the broadest possible use of the trade-space for aircraft applications. An integrated process and tool environment are described. This process has been applied in the areas of airframe-propulsion integration, thermal management and environmental control systems, control system integration and in the evaluation of more electric aircraft architectures.
A Conceptual Design Methodology for Variety Using TRIZ and QFD
Authors: Tan Runhua , Kraft Dieter
Published: April 2009

A method to select a key HOQ of QFD from the existed HOQs for variety of design is introduced first. Evolution of technique (ET) is used to find exciting requirements for the product to be designed and VOC driven by ET is formed. A new conceptual design model is illustrated, which integrate VOC driven by ET, QFD, inventive principles and separation principles of TRIZ. A design example is carried out using the model.
Atlantic Forcing of Persistent Drought in West Africa
Authors: Shanahan T. M. , Overpeck J. T. , Anchukaitis K. J. , Beck J. W. , Cole J. E. , Dettman D. L. , Peck J. A. , Scholz C. A. , King J. W.
Published: April 2009

Although persistent drought in West Africa is well documented from the instrumental record and has been primarily attributed to changing Atlantic sea surface temperatures, little is known about the length, severity, and origin of drought before the 20th century. We combined geomorphic, isotopic, and geochemical evidence from the sediments of Lake Bosumtwi, Ghana, to reconstruct natural variability in the African monsoon over the past three millennia. We find that intervals of severe drought lasting for periods ranging from decades to centuries are characteristic of the monsoon and are linked to natural variations in Atlantic temperatures. Thus the severe drought of recent decades is not anomalous in the context of the past three millennia, indicating that the monsoon is capable of longer and more severe future droughts.
Comment on "Atmospheric Hydroxyl Radical Production from Electronically Excited NO
2
and H
2
O"
Authors: Carr Scott , Heard Dwayne E. , Blitz Mark A.
Published: April 2009

Li
et al
. (Reports, 21 March 2008, p. 1657) suggested that the reaction between electronically excited nitrogen dioxide and water vapor is an important atmospheric source of the hydroxyl radical. However, under conditions that better approximate the solar flux, we find no evidence for OH production from this reaction.
Mirror Neurons Differentially Encode the Peripersonal and Extrapersonal Space of Monkeys
Authors: Caggiano Vittorio , Fogassi Leonardo , Rizzolatti Giacomo , Thier Peter , Casile Antonino
Published: April 2009

Actions performed by others may have different relevance for the observer, and thus lead to different behavioral responses, depending on the regions of space in which they are executed. We found that in rhesus monkeys, the premotor cortex neurons activated by both the execution and the observation of motor acts (mirror neurons) are differentially modulated by the location in space of the observed motor acts relative to the monkey, with about half of them preferring either the monkey's peripersonal or extrapersonal space. A portion of these spatially selective mirror neurons encode space according to a metric representation, whereas other neurons encode space in operational terms, changing their properties according to the possibility that the monkey will interact with the object. These results suggest that a set of mirror neurons encodes the observed motor acts not only for action understanding, but also to analyze such acts in terms of features that are relevant to generating appropriate behaviors.
Response to Comment on "Atmospheric Hydroxyl Radical Production from Electronically Excited NO
2
and H
2
O"
Authors: Li Shuping , Matthews Jamie , Sinha Amitabha
Published: April 2009

Carr
et al
. failed to detect hydroxyl radical formation from the reaction of excited state nitrogen dioxide with water, contrary to our findings. We present several reasons, based on energetic and spectroscopic considerations, why the OH radicals we observed from this reaction are not likely to be due to multiphoton excitation as they suggest.
A Contemporary Microbially Maintained Subglacial Ferrous "Ocean"
Authors: Mikucki Jill A. , Pearson Ann , Johnston David T. , Turchyn Alexandra V. , Farquhar James , Schrag Daniel P. , Anbar Ariel D. , Priscu John C. , Lee Peter A.
Published: April 2009

An active microbial assemblage cycles sulfur in a sulfate-rich, ancient marine brine beneath Taylor Glacier, an outlet glacier of the East Antarctic Ice Sheet, with Fe(III) serving as the terminal electron acceptor. Isotopic measurements of sulfate, water, carbonate, and ferrous iron and functional gene analyses of adenosine 5′-phosphosulfate reductase imply that a microbial consortium facilitates a catalytic sulfur cycle. These metabolic pathways result from a limited organic carbon supply because of the absence of contemporary photosynthesis, yielding a subglacial ferrous brine that is anoxic but not sulfidic. Coupled biogeochemical processes below the glacier enable subglacial microbes to grow in extended isolation, demonstrating how analogous organic-starved systems, such as Neoproterozoic oceans, accumulated Fe(II) despite the presence of an active sulfur cycle.
Contrasting Developmental Trajectories in the Earliest Known Tetrapod Forelimbs
Authors: Callier Viviane , Clack Jennifer A. , Ahlberg Per E.
Published: April 2009

Ichthyostega
and
Acanthostega
are the earliest tetrapods known from multiple near-complete skeletons, with
Acanthostega
generally considered the more primitive. New material indicates differing ontogenetic trajectories for their forelimbs: In
Ichthyostega
, the pattern of muscle attachment processes on small humeri (upper arm bones) resembles that in “fish” members of the tetrapod stem group such as
Tiktaalik
, whereas large humeri approach (but fail to attain) the tetrapod crown-group condition; in
Acanthostega
, both small and large humeri exhibit the crown-group pattern. We infer that
Ichthyostega
underwent greater locomotory terrestrialization during ontogeny. The newly recognized primitive characteristics also suggest that
Ichthyostega
could be phylogenetically more basal than
Acanthostega
.
Origin of Nucleosynthetic Isotope Heterogeneity in the Solar Protoplanetary Disk
Authors: Trinquier Anne , Elliott Tim , Ulfbeck David , Coath Christopher , Krot Alexander N. , Bizzarro Martin
Published: April 2009

Stable-isotope variations exist among inner solar system solids, planets, and asteroids, but their importance is not understood. We report correlated, mass-independent variations of titanium-46 and titanium-50 in bulk analyses of these materials. Because titanium-46 and titanium-50 have different nucleosynthetic origins, this correlation suggests that the presolar dust inherited from the protosolar molecular cloud was well mixed when the oldest solar system solids formed, but requires a subsequent process imparting isotopic variability at the planetary scale. We infer that thermal processing of molecular cloud material, probably associated with volatile-element depletions in the inner solar system, resulted in selective destruction of thermally unstable, isotopically anomalous presolar components, producing residual isotopic heterogeneity. This implies that terrestrial planets accreted from thermally processed solids with nonsolar isotopic compositions.
Anomalous Fractionations of Sulfur Isotopes During Thermochemical Sulfate Reduction
Authors: Watanabe Yumiko , Farquhar James , Ohmoto Hiroshi
Published: April 2009

Anomalously fractionated sulfur isotopes in many sedimentary rocks older than 2.4 billion years have been widely believed to be the products of ultraviolet photolysis of volcanic sulfur dioxide in an anoxic atmosphere. Our laboratory experiments have revealed that reduced-sulfur species produced by reactions between powders of amino acids and sulfate at 150° to 200°C possess anomalously fractionated sulfur isotopes: Δ
33
S = +0.1 to +2.1 per mil and Δ
36
S = –1.1 to +1.1 per mil. These results suggest that reactions between organic matter in sediments and sulfate-rich hydrothermal solutions may have produced anomalous sulfur isotope signatures in some sedimentary rocks. If so, the sulfur isotope record of sedimentary rocks may be linked to the biological and thermal evolution of Earth in ways different than previously thought.
A Ferroelectric Oxide Made Directly on Silicon
Authors: Warusawithana Maitri P. , Cen Cheng , Sleasman Charles R. , Woicik Joseph C. , Li Yulan , Kourkoutis Lena Fitting , Klug Jeffrey A. , Li Hao , Ryan Philip , Wang Li-Peng , Bedzyk Michael , Muller David A. , Chen Long-Qing , Levy Jeremy , Schlom Darrell G.
Published: April 2009

Metal oxide semiconductor field-effect transistors, formed using silicon dioxide and silicon, have undergone four decades of staggering technological advancement. With fundamental limits to this technology close at hand, alternatives to silicon dioxide are being pursued to enable new functionality and device architectures. We achieved ferroelectric functionality in intimate contact with silicon by growing coherently strained strontium titanate (SrTiO
3
) films via oxide molecular beam epitaxy in direct contact with silicon, with no interfacial silicon dioxide. We observed ferroelectricity in these ultrathin SrTiO
3
layers by means of piezoresponse force microscopy. Stable ferroelectric nanodomains created in SrTiO
3
were observed at temperatures as high as 400 kelvin.
Probing Interactions Between Ultracold Fermions
Authors: Campbell G. K. , Boyd M. M. , Thomsen J. W. , Martin M. J. , Blatt S. , Swallows M. D. , Nicholson T. L. , Fortier T. , Oates C. W. , Diddams S. A. , Lemke N. D. , Naidon P. , Julienne P. , Ye Jun , Ludlow A. D.
Published: April 2009

At ultracold temperatures, the Pauli exclusion principle suppresses collisions between identical fermions. This has motivated the development of atomic clocks with fermionic isotopes. However, by probing an optical clock transition with thousands of lattice-confined, ultracold fermionic strontium atoms, we observed density-dependent collisional frequency shifts. These collision effects were measured systematically and are supported by a theoretical description attributing them to inhomogeneities in the probe excitation process that render the atoms distinguishable. This work also yields insights for zeroing the clock density shift.
Recursive Processes in Self-Affirmation: Intervening to Close the Minority Achievement Gap
Authors: Cohen Geoffrey L. , Garcia Julio , Purdie-Vaughns Valerie , Apfel Nancy , Brzustoski Patricia
Published: April 2009

A 2-year follow-up of a randomized field experiment previously reported in
Science
is presented. A subtle intervention to lessen minority students' psychological threat related to being negatively stereotyped in school was tested in an experiment conducted three times with three independent cohorts (
N
= 133, 149, and 134). The intervention, a series of brief but structured writing assignments focusing students on a self-affirming value, reduced the racial achievement gap. Over 2 years, the grade point average (GPA) of African Americans was, on average, raised by 0.24 grade points. Low-achieving African Americans were particularly benefited. Their GPA improved, on average, 0.41 points, and their rate of remediation or grade repetition was less (5% versus 18%). Additionally, treated students' self-perceptions showed long-term benefits. Findings suggest that because initial psychological states and performance determine later outcomes by providing a baseline and initial trajectory for a recursive process, apparently small but early alterations in trajectory can have long-term effects. Implications for psychological theory and educational practice are discussed.