bluuebunny/crossref_metadata_2025 huggingface dataset:
A general paradigm for routine design—theory and implementation
Authors: Esterline Albert , Kota Sridhar
Published: March 2010

The concept of discretization of a design space is used to make initial selection of prior designs using specification matching, and to direct redesign with evaluation and iteration. A general paradigm for routine design has been developed and implemented in a system called IDS (Initial Design Selection.) For a given design domain, certain characteristics are identified that allow all specifications and models (which represent prior designs) in that design domain to be described in terms of their values or intervals that these values may lie in. These characteristics are seen as dimensions of a design space discretized into a finite number of partitions. Each partition is represented by a model, thought of as occupying its center. Each such model is associated with a deep model, which contains sufficient information for the modeled device, process, or system to be realized. Despite the fact that the models inhabiting the space are shallow, the paradigm comprises a relatively rich mathematical structure. This paper describes in detail a computational methodology to implement this domain-independent paradigm. The IDS paradigm presents a convenient and structured framework for acquiring and representing domain knowledge. This paper also briefly discusses an enhanced version of the system, which attempts iterative redesign directed by the particular mismatch between a specification and an otherwise promising model. To date, this methodology has been applied in a variety of design domains, including mechanism design, hydraulic component selection, assembly methods, and non-destructive testing methods.
Integration of qualitative and quantitative reasoning in iterative parametric mechanical design
Authors: Soo Von-Wun , Wang Tse-Ching
Published: March 2010

A framework IPD (Iterative Parametric Design) is proposed to assist the iterative parametric mechanical design process. To effectively find a set of satisfiable values for the design parameters the key is to find good heuristics to adjust or tune the parametric values resulting from previous design iterations. We propose that heuristics can come from two aspects by both qualitative and quantitative reasoning. Qualitative reasoning, based on confluences, provides global control over the feasible directions of variable adjustments, while quantitative reasoning, based on the dependency network and perturbation analysis, can be used to propose actual quantity of local variable adjustments. We used the design of a helical compression spring as an example to illustrate the performance of IPD system. We show that IPD can often find a solution faster than those without guidance of qualitative and quantitative reasoning.
Deriving a construct from site specific data: a knowledge level analysis
Authors: Dimitropoulos Anastasios
Published: March 2010

In wood engineering design, an important task is the derivation of a construct from site specific data. Human experts perform the task in two phases, first qualitatively and then quantitatively in a hierarchical fashion. COWEN (Computer Wood ENgineer) is a fully implemented research prototype expert system that performs the qualitative phase and makes two contributions to the technology of expert systems. The first contribution is a Knowledge Level specification of the task prior to considering Symbol Level implementation. This is important because expert systems have been defined as mostly symbolic processors in the literature. The second contribution is that this Knowledge Level specification has led to the conclusion that additional qualitative sciences, besides physics and geometry, are needed for an engineering task. This is an interesting discovery because qualitative reasoning research in Artificial Intelligence (AI) has approached engineering design from the viewpoints of physics and geometry only.
Intelligent gradient-based search of incompletely defined design spaces
Authors: Schwabacher Mark , Gelsey Andrew
Published: March 2010

Gradient-based numerical optimization of complex engineering designs offers the promise of rapidly producing better designs. However, such methods generally assume that the objective function and constraint functions are continuous, smooth, and defined everywhere. Unfortunately, realistic simulators tend to violate these assumptions. We present a rule-based technique for intelligently computing gradients in the presence of such pathologies in the simulators, and show how this gradient computation method can be used as part of a gradient-based numerical optimization system. We tested the resulting system in the domain of conceptual design of supersonic transport aircraft, and found that using rule-based gradients can decrease the cost of design space search by one or more orders of magnitude.
Modelling concept design evaluation
Authors: Green Graham
Published: March 2010

This paper describes the development of models to simulate the process of Concept Design Evaluation. The models are an amalgam of a number of statistically based methods and approaches taken from the probability, reliability, and quality domains. They assume that designers use decomposition of design to undertake evaluation at design characteristic level with the total design evaluation being achieved, in some way, via recomposition. The models described in this paper attempt to describe how designers may perform recomposition and hence total design evaluation. It is argued that the ability to model this human activity is important for the future development of knowledge-based design tools.
Spatial synthesis by disjunctive constraint satisfaction
Authors: Baykan Can A. , Fox Mark S.
Published: March 2010

The spatial synthesis problem addressed in this paper is the configuration of rectangles in 2D space, where the sides of the rectangles are parallel to an orthogonal coordinate system. Variables are the locations of the edges of the rectangles and their orientations. Algebraic constraints on these variables define a layout and constitute a constraint satisfaction problem. We give a new O(n2) algorithm for incremental path-consistency, which is applied after adding each algebraic constraint. Problem requirements are formulated as spatial relations between the rectangles, for example, adjacency, minimum distance, and nonoverlap. Spatial relations are expressed by Boolean combinations of the algebraic constraints; called disjunctive constraints. Solutions are generated by backtracking search, which selects a disjunctive constraint and instantiates its disjuncts. The selected disjuncts describe an equivalence class of configurations that is a significantly different solution. This method generates the set of significantly different solutions that satisfy all the requirements. The order of instantiating disjunctive constraints is critical for search efficiency. It is determined dynamically at each search state, using functions of heuristic measures called textures. Textures implement fail-first and prune-early strategies. Extensions to the model, that is, 3D configurations, configurations of nonrectangular shapes, constraint relaxation, optimization, and adding new rectangles during search are discussed.
Modelling spatial reasoning systems with shape algebras and formal logic
Authors: Chase Scott C.
Published: March 2010

The combination of the paradigms of shape algebras and predicate logic representations, used in a new method for describing designs, is presented. First-order predicate logic provides a natural, intuitive way of representing shapes and spatial relations in the development of complete computer systems for reasoning about designs. Shape algebraic formalisms have advantages over more traditional representations of geometric objects. Here we illustrate the definition of a large set of high-level design relations from a small set of simple structures and spatial relations, with examples from the domains of geographic information systems and architecture.
Qualitative sketch optimization
Authors: Mukerjee Amitabha , Agrawal Ram Bhushan , Tiwari Nivedan , Hasan Nusrat
Published: March 2010

The “sketch” drawn by a human designer represents a shape class of wider variability than can be captured by traditional CAD models; these typically work with parametrizations based on a nearly finished shape. Traditional Qualitative Reasoning is also unable to model this degree of ambiguity in shape. Cognitively, shapes are often represented in terms of an axial model. In defining 2D contours, such an axial representation is called the Medial Axis Transform or MAT. By perturbing the parameters of the MAT—length, link angle, and the node radius—one can define a shape class. Unlike the contour-to-MAT transform, which is well-known to be unstable, the MAT-to-contour process is an integrative process and is very stable. The variation in these parameters can be controlled by defining a suitable discretization over the parameter space. This leads to a broad class of similar shapes from which an optimized shape can be obtained for a given set of criteria. The optimizing criteria may involve the boundary description for each shape; the axial model is only used for generating the shape class. This Qualitative MAT model has been tested in several design optimization contexts, using Genetic Algorithms, and we show results for Automobile contours, IC engine parts, building profiles, etc.
Causality in constraint propagation
Authors: Habib Walid E. , Ward Allen C.
Published: March 2010

This paper defines, for use in design, rules for propagating “distribution constraints” through relationships such as algebraic or vector equations. Distribution constraints are predicate logic statements about the values that physical system parameters may assume. The propagation rules take into account “variation source causality”: information about when and how the values are assigned during the design, manufacturing, and operation of the system.
Dietary diversity score is related to obesity and abdominal adiposity among Iranian female youth
Authors: Azadbakht Leila , Esmaillzadeh Ahmad
Published: March 2010

Objective

To assess the relationship between diet and disease, consideration of whole-diet indices may be more informative than single-nutrient intake. The present study was conducted to report the relationship among dietary diversity score (DDS), obesity and abdominal adiposity among female university students.

Design

Cross-sectional study.

Setting

Isfahan, Iran.

Subjects

A representative sample of 289 healthy female students aged 18–28 years was selected randomly from Isfahan University of Medical Sciences, Iran. Usual dietary intake was assessed using a validated semi-quantitative FFQ. DDS was calculated according to the scoring of the five food groups based on the US Department of Agriculture Food Guide Pyramid. This is a score of diet variety, and shows the diversity of the consumed diet. Participants were categorised on the basis of quartile cut-off points of DDS. Potential confounders such as age, total energy intake and physical activity were considered in all the analyses.

Results

The means (sd) of BMI and waist circumference were 25·9 (sd5·1) kg/m2and 85·5 (sd14) cm, respectively. The probability of obesity decreased with quartiles of DDS (OR among quartiles: 1·00, 0·41, 0·31 and 0·21,P= 0·03; this was the same for abdominal adiposity: 1·00, 0·55, 0·36 and 0·21,P= 0·02). Those in the lowest quartile of the DDS had the highest risk for being overweight.

Conclusions

There were inverse associations among DDS, obesity and abdominal adiposity among the female students of Isfahan University. Further prospective investigations are needed to confirm this finding.
Food shopping transition: socio-economic characteristics and motivations associated with use of supermarkets in a North African urban environment
Authors: Tessier Sophie , Traissac Pierre , Bricas Nicolas , Maire Bernard , Eymard-Duvernay Sabrina , El Ati Jalila , Delpeuch Francis
Published: March 2010

Objective

In the context of the nutrition transition and associated changes in the food retail sector, to examine the socio-economic characteristics and motivations of shoppers using different retail formats (large supermarkets (LSM), medium-sized supermarkets (MSM) or traditional outlets) in Tunisia.

Design

Cross-sectional survey (2006). Socio-economic status, type of food retailer and motivations data were collected during house visits. Associations between socio-economic factors and type of retailer were assessed by multinomial regression; correspondence analysis was used to analyse declared motivations.

Setting

Peri-urban area around Tunis, Tunisia, North Africa.

Subjects

Clustered random sample of 724 households.

Results

One-third of the households used LSM, two-thirds used either type of supermarket, but less than 5 % used supermarkets only. Those who shopped for food at supermarkets were of higher socio-economic status; those who used LSM were much wealthier, more often had a steady income or owned a credit card, while MSM users were more urban and had a higher level of education. Most households still frequently used traditional outlets, mostly their neighbourhood grocer. Reasons given for shopping at the different retailers were most markedly leisure for LSM, while for the neighbourhood grocer the reasons were fidelity, proximity and availability of credit (the latter even more for lower-income customers).

Conclusions

The results pertain to the transition in food shopping practices in a south Mediterranean country; they should be considered in the context of growing inequalities in health linked to the nutritional transition, as they differentiate use and motivations for the choice of supermarkets v. traditional food retailers according to socio-economic status.
Study on the opinion of university students about the themes of the origin of Universe and evolution of life
Authors: de Souza Rogério F. , de Carvalho Marcelo , Matsuo Tiemi , Zaia Dimas A.M.
Published: March 2010

This paper reports the results of a questionnaire administered to university students, about several questions involving the origin of the Universe and life and biological evolution, as well as questions related to more common scientific themes. As few as between 2.4% (philosophy students) and 14% (geography students) did not accept the theory of evolution, because they believed in creation as described in the Bible. However, between 41.5% (philosophy students) and 71.3% (biology students) did not see any conflict between religion and evolution. About 80% of the students believed that the relationship between lung cancer and smoking is well established by science, but this number falls to 65% for biological evolution and 28.9% for the big bang theory. It should be pointed out that for 24.5% and 7.4% of the students the big bang theory and biological evolution, respectively, are poorly established by science. The students who self-reported being Christian but not Roman Catholic are more conservative in the acceptance of biological evolution and the old age of Earth and the Universe than are other groups of students. Other factors, such as family income and the level of education of parents, appear to influence the students' acceptance of themes related to the origin of the Universe and biological evolution.
Pathogenese der funktionellen Erkrankungen des Verdauungstrakts aus interdisziplinärer Sicht
Authors: Egloff  , Beer  , Gschossmann  , Sendensky  , Känel von
Published: March 2010

Funktionelle Störungen des Verdauungstrakts kommen weltweit vor und sind sehr häufig. Die Forschung der letzten Jahre vermittelt zunehmend exakteres Wissen über die Pathogenese dieser Störungen: Es ergibt sich das Bild einer komplexen Dysregulation mit enteralen, neuroenteralen, vegetativ-autonomen wie auch zentral­nervösen Aspekten. Die psychische Verfassung der Betroffenen spielt v.a. hinsichtlich stressphysiologischer und körperperzeptiver Aspekte eine Rolle. Ziel dieses Artikels ist aus interdisziplinärer Sicht einen Überblick zu vermitteln über den aktuellen Stand der Erkenntnisse zur Pathogenese dieser Störungen. Ein sachliches Verständnis dieser Störungen ist die Grundlage für einen adäquaten Umgang mit den von diesen Störungen betroffenen Patienten und Basis für rationale Therapieansätze.
Un diagnostic de maladie coeliaque peut en cacher un autre
Authors: Yersin  , Dewarrat Maillard
Published: March 2010

Die Common Variable Immunodeficiency (CVID) ist nach dem selektiven IgA-Mangel der häufigste primäre Immundefekt. Aufgrund der unterschiedlichen Symptomatik und des variablen Manifestationsalters kann die CVID verschiedene andere Pathologien imitieren und wird deshalb häufig erst im späteren Krankheitsverlauf diagnostiziert. Eine zu späte Diagnose kann irreversible Organschäden zur Folge haben, wovon die meisten durch eine frühe Behandlung vermieden werden können. Deshalb ist eine frühe Diagnose durch den Hausarzt bei Patienten mit rezidivierenden Infekten oder anderen typischen klinischen Manifestationen von grosser Wichtigkeit.
„Lebenskunst” als neoliberale Selbstregierungstechnik?
Authors: Hafke Christel
Published: March 2010

Zusammenfassung. Foucaults Wiederbelebung der Lebenskunstthematik nährt sich aus einer alten Hoffnung, die Trennung von Kunst und Leben überwinden und sich dadurch aus habitualisierten Identitätsvorgaben lösen zu können. Das Leben als ein Kunstwerk zu gestalten korrespondiert dabei mit seinem Wunsch, „nicht so regiert zu werden”. Dies bedeutet immer auch Widerstand gegen die in Disziplinierungs- und Normalisierungsprozessen vorgegebenen Subjektformen und erfordert eine bestimmte Haltung der nicht teleologischen Übung. Die Autorin geht auf zentrale Begriffe Foucaults wie Macht, Subjektivierung, Regierung und Widerständigkeit ein, ohne welche die Besonderheit seiner Lebenskunstvorstellung nicht hinreichend verstanden werden kann. Es wird deutlich gemacht, dass die Lebenskunstprojekte der kulturellen Bildung, obwohl sie sich auf Foucault berufen, in einem anderen Verständnis von Gesellschaft verortet sind und sehr anderen Intentionen folgen, die mit Foucaults Ansatz nicht zusammenpassen. Eine Orientierung an Kompetenzen und Wettbewerb steht seinem Ansatz diametral entgegen.
Tanzend in den Herbst des Lebens
Authors: Pürschel Renate
Published: March 2010

Zusammenfassung. Die tanztherapeutische Arbeit mit alten und pflegebedürftigen Menschen zeigt wie stark die Bewohner auf Kontakte und Zuwendungen reagieren und unterstreicht, dass die nonverbale Therapieform besonders geeignet ist für kognitiv, sprachlich und im Sozialverhalten beeinträchtigte Menschen. Im Folgenden wird die Alterspflege, die typischen Alterskrankheiten, die allgemeine Lebenssituation und vier exemplarische tanztherapeutische Settings erläutert. Als Fazit sind die verbesserte Kommunikation untereinander, die aufgehellte Stimmung, seelische Ausgeglichenheit sowie eine verbesserte physische Beweglichkeit und Steigerung der kognitiven Fähigkeiten herauszustellen. Die künstlerische Tanztherapie setzt an den Ressourcen der Bewohner an und stärkt das Selbstbewusstsein und Selbstwertgefühl: sie fühlen sich kreativ, erfahren sich als Teil einer Gemeinschaft, fühlen sich bestätigt, angenommen und genussfähig.
Relative rates of sea‐air heat transfer and frictional drag in very high winds
Authors: Haus Brian K. , Jeong Dahai , Donelan Mark A. , Zhang Jun A. , Savelyev Ivan
Published: March 2010

Hurricanes are fueled by evaporation and convection from the ocean and they lose energy through the frictional drag of the atmosphere on the ocean surface. The relative rates of these processes have been thought to provide a limit on the maximum potential hurricane intensity. Here we report laboratory observations of these transfers for scaled winds equivalent to a strong Category 1 hurricane (38 ms−1). We show that the transfer coefficient ratio holds closely to a level of ∼0.5 even in the highest observed winds, where previous studies have suggested there is a distinct regime change at the air‐sea interface. This value is well below the expected threshold value for intense hurricanes of 0.75. Recent three‐dimensional model studies also find that the coefficient ratio can be much lower than 0.75, which suggests that other factors such as eyewall and/or vortex dynamics are responsible for the formation of very strong hurricanes.
Exploring sources of magnetospheric plasma using multispecies MHD
Authors: Welling D. T. , Ridley A. J.
Published: March 2010

A persistent, unresolved problem in terrestrial magnetospheric physics is determining the dominant source and associated entry mechanism for plasma in the Earth's magnetosphere. This study uses the multispecies MHD code, Block Adaptive Tree Solar Wind Roe‐Type Upwind Scheme (BATS‐R‐US), to investigate this issue. Two proton species, ionospheric origin and solar wind origin, are defined in the system and the evolution of each population is followed under different idealized solar wind conditions. It is found that during southward oriented interplanetary magnetic field (IMF), the dominant source is ionospheric plasma entering deep down tail through reconnecting field lines. During northward IMF, the dominant source is solar wind plasma entering through the flanks of the magnetosphere. This two‐mode behavior is tested through data‐model comparisons of real world simulations. Comparisons of model results against Los Alamos National Laboratory Magnetospheric Plasma Analyzer density, pressure, and inferred oxygen content support the conclusions of the idealized results.
Wave normal angles of magnetospheric chorus emissions observed on the Polar spacecraft
Authors: Haque N. , Spasojevic M. , Santolík O. , Inan U. S.
Published: March 2010

Using data from the High Frequency Waveform Receiver on board the Polar spacecraft, 1,765 and 993 wave normal angles have been analyzed for 13 orbits containing upper band magnetospheric chorus emissions and 15 orbits containing lower band emissions, respectively. The purpose of this study is to characterize the distribution of the polar wave normal angle, θ, for chorus emissions as a function of magnetic latitude, λ. Understanding wave normal angles is an important step in evaluating resonant wave‐particle interactions. For upper band chorus, wave normal angles tend to remain at or rise toward the resonance cone angle for low latitudes and midlatitudes but move away from the resonance cone angle at higher latitudes. For lower band chorus, wave normal angles with values θ < 20° have the highest probability of occurrence in the latitude range of 10°–50°. Just off the equator, 10° ≤ λ < 25°, there exists a secondary occurrence peak in the range of 50° ≤ θ < 70°. The probability of observing these higher wave normal angles decreases with increasing latitude. The time‐averaged Poynting flux, S, is much larger for lower band chorus waves, which have a mean value of 8.5 × 10−8 W/m2, than for upper band chorus waves, which have a mean value of 1.4 × 10−9 W/m2. S is fairly evenly distributed about its median value, 3.1 × 10−10 W/m2, for all wave normal angles for upper band chorus but deceases as θ increases for lower band chorus.
Longitudinal development of low‐latitude ionospheric irregularities during the geomagnetic storms of July 2004
Authors: Li Guozhu , Ning Baiqi , Hu Lianhuan , Liu Libo , Yue Xinan , Wan Weixing , Zhao Biqiang , Igarashi K. , Kubota Minoru , Otsuka Yuichi , Xu J. S. , Liu J. Y.
Published: March 2010

During the period 22–28 July 2004, three geomagnetic storms occurred due to a sequence of coronal mass ejections. In this paper we present and discuss the ionospheric observations from a set of in situ satellites and ground‐based GPS total electron content and scintillation receivers, a VHF radar, and two chains of ionosondes (∼300°E and ∼120°E, respectively) that provide the evolutionary characteristics of equatorial and low‐latitude ionospheric irregularities versus longitude during these storm periods. It is found that the irregularities occurred over a wide longitudinal range, extending from around 300°E to 120°E on storm days 25 and 27 July 2004. On 25 July plasma bubbles (PBs) began premidnight in America and postmidnight in Southeast Asia. On 27 July the occurrence of irregularities followed the sunset terminator and was observed sequentially after sunset from American to Southeast Asian longitudes. Past studies have reported that storm‐time low‐latitude ionospheric irregularities are mostly confined to a narrower longitude range, <90°, after sunset hours and are associated with the prompt penetration of eastward electric fields (PPEFs) into low latitudes. In June solstice months the occurrence of range‐type spread F or PBs is very low in Southeast Asian and South American sectors. In contrast, the present results indicate that geomagnetic storms triggered the wide longitudinal development of PBs. In the American sector this was probably due to the effects of PPEFs on both storm days. However, in the Southeast Asian sector the PBs on the 2 days probably arose from disturbance dynamo electric field (DDEF), PPEF, and gravity wave seeding effects. This study further shows that under complex storm conditions, besides the long duration or multiple penetrations, the combined effects of PPEFs and DDEFs could result in a wide longitude extent of ionospheric irregularities at times.
Large‐scale traveling ionospheric disturbances impacting equatorial ionization anomaly development in the local morning hours of the Halloween Superstorms on 29–30 October 2003
Authors: Horvath Ildiko , Lovell Brian C.
Published: March 2010

This study investigates the development of EIA‐like features during the Halloween Superstorms. These features are similar to a well‐developed equatorial ionospheric anomaly (EIA) and therefore suggest superfountain effects. We tracked EIA‐like features in the early‐morning sector of 29–30 October 2003 and at around midday on 30 October. Their plasma environment was studied with field‐aligned plasma density, vertical plasma drift, electron temperature, and vertical plasma flow profiles. Coupled thermosphere‐ionosphere plasmasphere (CTIP) simulations reproduced storm‐generated equatorward wind surges. When these EIA‐like features appeared early morning on 29–30 October, there was no forward fountain circulation; only large‐scale traveling ionospheric disturbances (TIDs) and strong equatorward winds were present. These provide observational evidence that large‐scale TIDs created large plasma depletions over the dip equator and with the aid of equatorward winds some large enhancements at ∼±30°N (geomagnetic), resulting in the development of early‐morning EIA‐like features. We identified TID signatures in the equatorial and midlatitude ionosonde and magnetometer data, and studied EIA‐like features at around midday on 30 October utilizing non‐field‐aligned TOPEX TEC (2000 UT) and published CHAMP TEC (2030 UT; 2200 UT) line plots. According to our analysis, the EIA‐like features seen in the TEC data were created by large‐scale TIDs at 2000 and 2030 UT and by the combined effects of large‐scale TIDs and forward superfountain at 2200 UT. CTIP simulations demonstrate the crucial role of the neutral winds' mechanical or direct effects in the development of high plasma densities at low midlatitudes.
CO2 fluxes across the air‐sea interface in the southeastern Beaufort Sea: Ice‐free period
Authors: Mucci Alfonso , Lansard Bruno , Miller Lisa A. , Papakyriakou Timothy N.
Published: March 2010

Surface mixed layer CO2 fugacities (fCO2‐sw) calculated from carbonate system parameters in the southeastern Beaufort Sea during the ice‐free period ranged from 240 to 350 μatm in fall 2003 and from 175 to 515 μatm in summer 2004. The surface mixed layer remains mostly undersaturated with respect to atmospheric CO2 (378 μatm) and, therefore, acts as a potential CO2 sink throughout this period. Air‐sea CO2 fluxes (FCO2) were first computed assuming ice‐free conditions and ranged from −32.4 to +8.6 mmol m−2 d−1 in fall 2003 and summer 2004, respectively. Then we included a reduction factor to account for ice cover (ic) and we computed the resulting fluxes (FCO2‐ic). In fall 2003, FCO2‐ic ranged from −4.7 mmol m−2 d−1 in the relatively open water of the Cape Bathurst Polynya to −0.1 mmol m−2 d−1 in the southeastern Beaufort Sea, limited by the presence of the multiyear sea ice. In summer 2004, FCO2‐ic ranged from −13.1 mmol m−2 d−1 on the western Mackenzie Shelf to +8.6 mmol m−2 d−1 at Cape Bathurst; the variability being ascribed to competing effects of vertical mixing, temperature variations, and possibly biological production. On average, a net sink of −2.3 ± 3.5 mmol m−2 d−1 was estimated for the ice‐free period over the study area. Nevertheless, the FCO2 displays strong variability due to ice coverage, freshwater input, and upwelling events. The potential responses (direction and intensity of potential feedbacks) of the carbon cycle in the study area to a changing Arctic climate are discussed.
Silica coatings in the Ka'u Desert, Hawaii, a Mars analog terrain: A micromorphological, spectral, chemical, and isotopic study
Authors: Chemtob Steven M. , Jolliff Bradley L. , Rossman George R. , Eiler John M. , Arvidson Raymond E.
Published: March 2010

High‐silica materials have been observed on Mars, both from orbit by the CRISM spectrometer and in situ by the Spirit rover at Gusev Crater. These observations potentially imply a wet, geologically active Martian surface. To understand silica formation on Mars, it is useful to study analogous terrestrial silica deposits. We studied silica coatings that occur on the 1974 Kilauea flow in the Ka'u Desert, Hawaii. These coatings are typically composed of two layers: a ∼10 μm layer of amorphous silica, capped by a ∼1 μm layer of Fe‐Ti oxide. The oxide coating is composed of ∼100 nm spherules, suggesting formation by chemical deposition. Raman spectroscopy indicates altered silica glass as the dominant phase in the silica coating and anatase and rutile as dominant phases in the Fe‐Ti coating; jarosite also occurs within the coatings. Oxygen isotopic contents of the coatings were determined by secondary ion mass spectrometry (Cameca 7f and NanoSIMS). The measured values, δ18OFe‐Ti = 14.6 ± 2.1‰, and δ18Osilica = 12.1 ± 2.2‰ (relative to SMOW), are enriched in 18O relative to the basalt substrate. The observations presented are consistent with a residual formation mechanism for the silica coating. Acid‐sulfate solutions leached away divalent and trivalent cations, leaving a silica‐enriched layer behind. Micrometer‐scale dissolution and reprecipitation may have also occurred within the coatings. Chemical similarities between the Hawaiian samples and the high‐silica deposits at Gusev suggest that the Martian deposits are the product of extended periods of similar acid‐sulfate leaching.
A Community Approach to Earth Systems Modeling
Authors: Voinov Alexey A. , DeLuca Cecelia , Hood Raleigh R. , Peckham Scott , Sherwood Christopher R. , Syvitski James P. M.
Published: March 2010

Earth science often deals with complex systems spanning multiple disciplines. These systems are best described by integrated models built with contributions from specialists of many backgrounds. But building integrated models can be difficult; modular and hierarchical approaches help to manage the increasing complexity of these modeling systems, but there is a need for framework and integration methods and standards to support modularity. Complex models require many data and generate lots of output, so software and standards are required for data handling, model output, data distribution services, and user interfaces. Complex modeling systems must be efficient to be useful, so they require contributions by software engineers to ensure efficient architectures, accurate numerics, and implementation on fast computers. Further, integrated model systems can be difficult to learn and use unless adequate documentation, training, and support are provided.
Observing and Understanding Tropospheric Ozone Changes: Tropospheric Ozone Changes Workshop; Boulder, Colorado, 14–16 October 2009
Authors: Logan Jennifer , Schultz Martin , Oltmanz Samuel
Published: March 2010

Prompted by the lack of consensus on, and the need to assess current understanding of, long‐term changes in tropospheric ozone, a workshop was held in Colorado to (1) evaluate the consistency of data records; (2) assess robust long‐term changes; (3) determine how to combine observations and model studies; and (4) define research and observation needs for the future.

At the workshop, long‐term ozone records from regionally representative surface and mountain sites, ozonesondes, and aircraft were reviewed by region. In western Europe there are several time series of ∼15–40 years from all platforms. Overall, they show a rise in ozone into the middle to late 1990s and a leveling off, or in some cases declines, in the 2000s, in general agreement with precursor emission changes. However, significant differences in detail in the time series from nearby locations provide less confidence in changes before the late 1990s.
Dual reservoir structure at Soufrière Hills Volcano inferred from continuous GPS observations and heterogeneous elastic modeling
Authors: Foroozan Roozbeh , Elsworth Derek , Voight Barry , Mattioli Glen S.
Published: March 2010

Most inversions of geodetic data for volcanic systems assume homogeneous media. Here we examine the effect of inhomogeneous media using axisymmetric finite element models of Soufrière Hills Volcano (SHV), to show that homogeneous elastic crustal models underestimate both the depth and excess pressure of the deformation source. Continuous GPS data from 1999 to 2009 are then used to infer that the SHV system has multiple crustal pressure sources. For a dual reservoir volcanic model, a deep reservoir located within the mid crust undergoes volume changes approximately an order of magnitude larger than those of the shallow reservoir.
Observation of artificial spread‐F and large region ionization enhancement in an HF heating experiment at HAARP
Authors: Kuo Spencer , Snyder Arnold
Published: March 2010

A large‐scale ionospheric modification by HF heaters was explored via HAARP digisonde operated in a fast mode. The results show that the ionogram virtual heights and the height spread of the ordinary‐wave sounding echoes were changed significantly by the O‐mode heater; the X‐mode heater imposed no noticeable effect on the ionograms. The enhanced virtual height spread exceeds 40 km, more than 15% of sounding echo's average virtual height. The heater downshifted/upshifted the virtual height in the low/high frequency region around the heater frequency by as much as 15 and 7.5 km. The modifications were developing to last more than 10 seconds after the heater was turned off. The perturbed ionosphere took more than 60 seconds to recover. The modified electron density distribution indicates that the electron density and temperature increases exceed 10% and 25% over a large altitude region (>30 Km) from below to above the HF reflection height.
Nez et personnalité
Authors: Lejoyeux Joseph
Published: March 2010

Le nez, situé au centre de l'étage moyen de la face, joue un rôle prépondérant dans la communication de l'être humain avec le monde extérieur, visible et invisible. Sa morphologie est modelée par le jeu des muscles de la mimique qui l'animent de manière incessante et spécifique, en fonction du caractère et du tempérament. Leurs rôles respectifs seront donc rappelés, avant de décrire les différentes approches typologiques qui permettent, au delà de la forme, d'appréhender la nature profonde de la personnalité.
Exploration radiologique du nez, des fosses nasales et des sinus
Authors: Pasquet G. , Cavezian R.
Published: March 2010

Hormis l'appendice nasal, dont l'exploration radiologique isolée est fréquente dans les traumatismes, toutes les autres structures anatomiques de cette région faciale moyenne nécessitent une exploration radiologique globale.

Les méthodes radiologiques standard et tomographiques sont dans la grande majorité des cas suffisantes. Encore faut-il que l'exploration soit complète, nécessitant la multiplication raisonnée des incidences...

Parfois, l'examen tomodensitométrique facilite le diagnostic, permettant en particulier le bilan d'extension des tumeurs de cette région.

De grands espoirs radio-anatomiques semblent pouvoir être fondés sur l'apport des méthodes de reconstruction tridimensionnelle de surface, réalisée grâce aux nouveaux scanographes.

Enfin, la technique d'imagerie par résonance magnétique constitue le dernier élément de l'arsenal d'imagerie moderne.
Naissance du nez
Authors: Nazat Dominique
Published: March 2010

Le nez occupe une place de choix dans les grands bouleversements qui marquent le modelage embryologique de la face. En s'appuyant sur quelques schémas “clés”, l'auteur dresse un résumé des grands événements autour desquels s'articule l'édification de la future pyramide nasale.
Obstruction nasale et ventilation orale. Le point de vue de l'oto-rhino-laryngologiste
Authors: Récamier Max
Published: March 2010

Chez l'enfant, la principale cause d'obstruction nasale entraînant une ventilation orale avec ses incidences possibles sur la morphologie maxillo-faciale, est l'hypertrophie des végétations adénoïdes, éléments du cercle lymphatique de WALDEYER, situées à la partie supérieure du rhino-pharynx. Leur rôle physiologique est encore imparfaitement connu, et les indications de leur ablation chirurgicale doivent faire l'objet d'une attitude nuancée selon les cas.
Méthode numérique informatisée pour la conversion en âge dentaire des stades de maturation
Authors: Proy Elisabeth , Proy Gérard P. , Spillone Jean-Paul , Gautier Nicole
Published: March 2010

La méthode présentée permet un calcul rapide et plus précis que manuellement de l'âge dentaire-maturation de nos enfants. Les principes généraux sont exposés et l'application à la programmation sur ordinateur APPLE IIe est fournie. L'application à tout autre population est aisée par simple détermination des nouveaux paramètres nécessaires et spécifiques d'un échantillon donné quant à sa maturation dentaire.
Les transpositions de canines : traitements interceptifs
Authors: Attia Yves , Favot Pierre
Published: March 2010

La transposition des canines est une anomalie particulière. Ses principales caractéristiques cliniques sont tout d'abord rappelées, ainsi que les éléments de son diagnostic.

Les différentes possibilités thérapeutiques interceptives qui s'offrent au praticien sont ensuite envisagées.

Une classification originale des transpositions en quatre groupes permettra d'en faciliter le pronostic et le choix thérapeutique.
Interception des malocclusions dans les cas
de Classe I d'Angle
Authors: Martinez Marguerite , Sampéré Jeanne
Published: March 2010

Tout en distinguant, grâce à la classification d'Anderson, les différentes malocclusions regroupées habituellement au sein de la Classe I d'Angle, les auteurs précisent les indications et les types de traitements interceptifs réalisables dans ces cas. Un exemple d'interception est montré pour chacune des malocclusions envisagées.
Examen critique de la technique de l'arc plan
Authors: Philippe Julien
Published: March 2010

Parce qu'elle repose sur l'utilisation d'un arc continu, la technique de l'arc droit semble critiquable, du point de vue de l'analyse mécanique, lors de la phase initiale des traitements (celle des grands déplacements).

Par contre, lorsqu'il s'agit de donner aux dents l'orientation et la position voulue, les attaches propres à la technique ne présentent que des avantages. Il en est de même pour la phase de finition, encore qu'une finition parfaite ne puisse être obtenue sans recours aux pinces, ou à des appareils amovibles ("tooth positioner").
Le Targ et son évolution
Authors: Altounian Gérard , Fillion Didier
Published: March 2010

Les auteurs rappellent brièvement les origines de l'orthodontie linguale. Les pionniers de cette technique purent exprimer leur talent grâce à un protocole prothétique spécifique articulé autour du Targ. Après avoir décrit ce matériel, les auteurs montrent l'évolution de cette nouvelle machine, qui bénéficie de nombreuses améliorations françaises dont la plus importante est l'adjonction d'un appareil de mesure des épaisseurs. Pour faciliter le travail du clinicien dans la confection des arcs, les informations fournies par le Targ de la seconde génération sont intégrées dans des programmes informatiques D.A.L.I. 1, puis D.A.L.I. 2.
L'inclinaison vestibulo-linguale naturelle des dents
Authors: Demange Christian
Published: March 2010

L'inclinaison vestibulo-linguale naturelle des dents, ou torque, est recherchée à travers les résultats de diverses études statistiques. Ces résultats sont discutés et comparés. Les moyennes de torque de chaque dent sont aussi analysées en fonction de mesures squelettiques dans les trois sens de l'espace pour essayer d'individualiser les prescriptions de torque dans les techniques d'arc plan.
Heat Capacity of Liquids: Critical Review and Recommended Values. Supplement II
Authors: Zábranský Milan , Kolská Zdenka , Růžička Vlastimil , Domalski Eugene S.
Published: March 2010

A study was carried out in which new experimental data on heat capacities of pure liquid organic and some inorganic compounds were compiled and critically evaluated and recommended values provided. The bulk of the compiled data covers data published in the primary literature between 2000 and 2006 and includes some data published in 2007. However, some data from older sources are also included. The list of compound families covered was extended to include ionic liquids. Parameters of correlating equations for the temperature dependence of heat capacities of liquids were developed. This paper is an update of a two volume monograph entitled Heat Capacity of Liquids: Critical Review and Recommended Values by Zábranský et al. [J. Phys. Chem. Ref. Data 30, 1199 (2001)], which was published in 1996 in the Journal of Physical and Chemical Reference Data as Monograph No. 6, and of Supplement I.
Pulse shape influence on the atmospheric barrier discharge
Authors: Martens T. , Bogaerts A. , van Dijk J.
Published: March 2010

In this letter we compare the effect of a radio-frequency sine, a low frequency sine, a rectangular and a pulsed dc voltage profile on the calculated electron production and power consumption in the dielectric barrier discharge. We also demonstrate using calculated potential distribution profiles of high time and space resolution how the pulsed dc discharge generates a secondary discharge pulse by deactivating the power supply.
Effect of hot phonon lifetime on electron velocity in InAlN/AlN/GaN heterostructure field effect transistors on bulk GaN substrates
Authors: Leach J. H. , Zhu C. Y. , Wu M. , Ni X. , Li X. , Xie J. , Özgür Ü. , Morkoç H. , Liberis J. , Šermukšnis E. , Matulionis A. , Paskova T. , Preble E. , Evans K. R.
Published: March 2010

We report on electron velocities deduced from current gain cutoff frequency measurements on GaN heterostructure field effect transistors (HFETs) with InAlN barriers on Fe-doped semi-insulating bulk GaN substrates. The intrinsic transit time is a strong function of the applied gate bias, and a minimum intrinsic transit time occurs for gate biases corresponding to two-dimensional electron gas densities near 9.3×1012 cm−2. This value correlates with the independently observed density giving the minimum longitudinal optical phonon lifetime. We expect the velocity, which is inversely proportional to the intrinsic transit time, to be limited by scattering with non equilibrium (hot) phonons at the high fields present in the HFET channel, and thus, we interpret the minimum intrinsic transit time in terms of the hot phonon decay. At the gate bias associated with the minimum transit time, we determined the average electron velocity for a 1.1 μm gate length device to be 1.75±0.1×107 cm/sec.
Model of tunneling transistors based on graphene on SiC
Authors: Michetti Paolo , Cheli Martina , Iannaccone Giuseppe
Published: March 2010

Recent experiments shown that graphene epitaxially grown on Silicon carbide (SiC) can exhibit a energy gap of 0.26 eV, making it a promising material for electronics. With an accurate model, we explore the design parameter space for a fully ballistic graphene-on-SiC tunnel field-effect transistors, and assess the dc and high frequency figures of merit. The steep subthreshold behavior can enable ION/IOFF ratios exceeding 104 even with a low supply voltage of 0.15 V, for devices with gatelength down to 30 nm. Intrinsic transistor delays smaller than 1 ps are obtained. These factors make the device an interesting candidate for low-power nanoelectronics beyond CMOS.
Surface acoustic wave mediated dielectrophoretic alignment of rolled-up microtubes in microfluidic systems
Authors: Kong X. H. , Deneke Ch. , Schmidt H. , Thurmer D. J. , Ji H. X. , Bauer M. , Schmidt O. G.
Published: March 2010

The alignment behavior of solution dispersed rolled-up microtubes by surface acoustic waves (SAW) is demonstrated. In contrast to the random alignment of rolled-up insulated silicon oxide tubes, metallic chromium tubes can be effectively aligned and assembled into “tube-chains” parallel to the SAW propagation direction. The experiments suggest that the tube orientation is mainly determined by the dielectrophoresis (DEP) forces acting on the tubes. The DEP forces arise from the induced dipole moment of the tubes in the SAW generated piezoelectric field on the LiNbO3 substrate.
Temporal and spectral control of single-photon frequency upconversion for pulsed radiation
Authors: Gu Xiaorong , Huang Kun , Li Yao , Pan Haifeng , Wu E , Zeng Heping
Published: March 2010

We demonstrate efficient single-photon detection at 1.04 μm with quite low background counts by using the frequency upconversion detection technique with pulsed single-photon source and strong pump field prepared from two synchronized fiber lasers. Temporal and spectral control of the pump and signal lasers enabled an upconversion efficiency of 81.1%. As the system was pumped at a wavelength longer than that of the signal, the corresponding background counts were reduced down to 1.5×103 s−1 due to efficient suppression of parametric fluorescence in the periodic poled lithium niobate crystal.
Enhanced exciton migration in electrospun poly[2-methoxy-5- (2′-ethylhexyloxy)-1,4- phenylenevinylene]/poly(vinyl pyrrolidone) nanofibers
Authors: Zhou Rongtang , Chen Wei , Jiang Xingyu , Wang Shufeng , Gong Qihuang
Published: March 2010

We present the studies on static and transient optical characteristics of electrospun poly[2-methoxy-5-(2′-ethylhexyloxy)-1,4- phenylenevinylene]/poly(vinyl pyrrolidone) (MEH-PPV/PVP) nanofibers. [6,6]-phenyl-C61 butyric acid methyl ester is mixed into the polymer matrix, working as quenchers to optical excitons. Comparing with the spin-coated films, the nanofibers exhibit enhanced exciton migration in speed and amplitude. The results are explained together with photoluminescent spectra blueshifting and longer exciton lifetime. Reduced aggregation and long-range order simultaneously induced by electric field are regarded as the mechanism for the phenomena.
Use of fluorine-doped tin oxide instead of indium tin oxide in highly efficient air-fabricated inverted polymer solar cells
Authors: Baek Woon-Hyuk , Choi Mijung , Yoon Tae-Sik , Lee Hyun Ho , Kim Yong-Sang
Published: March 2010

The stability and efficiency of organic solar cells (OSCs) were improved using thermally stable fluorine-doped tin oxide (FTO) as the bottom electrode and poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) and TiO2 as the buffer layers. The TiO2 layer between FTO and the P3HT:PCBM active layer improved the interface characteristics for a better charge transfer. The PEDOT:PSS layer retarded the oxygen diffusion to the active layer. A maximum power conversion efficiency of 4.3% was obtained for the inverted structure of FTO/TiO2/P3HT:PCBM/PEDOT:PSS/Ag with a stable performance, and the cell retained over 65% of its initial efficiency after 500 h. Additionally, the OSCs were fabricated using all-solution based vacuum-free processes with screen printing for the Ag electrode and the results were comparable to the device that used an evaporated Ag electrode.