bluuebunny/crossref_metadata_2025 huggingface dataset:
Research on Heavy Oil Thermal Recovery by CO2 Steam Flooding with Help of Combination of Borehole-Surface Electric Potential and Cross-Borehole Electric Potential
Authors: Su Benyu , Fujimitsu Yasuhiro
Published: February 2012

With an increasing tendency towards more demand for energy resources, the supply of energy as a focus of global strategy is attracting more and more attention from the world. However, on the one hand, conventional hydrocarbon resources are decreasing gradually, and therefore it is definitely an urgent task to search for renewable and replaceable resources at the present time. On the other hand, it has been proved that the total reserves of heavy oil are already up to 1105×108 tons around the world, which means that exploring heavy oil can be a beneficial supplement for alleviating the shortage of oil and gas. Moreover, it is noteworthy that because the heavy oil can be exploited by heated CO2, collecting and consuming CO2 during the production process will help to relieve global warming.

In this study, we take the feasibility of heavy oil recovery by CO2 steam into consideration only from the viewpoint of geophysics. In the process of research, with the help of borehole-surface electric potential and cross-borehole electric potential, the entire procedures from heating heavy oil reservoir and optimizing the location of well to deciding the layer of perforation are exhibited completely. In the course of calculation, potential distributions corresponding to a point source of current are acquired by solving the Poisson equation using a direct and explicit finite difference technique for a lower half-space with 3-D distribution of conductivity. As for computation of a large sparse matrix, the technique of nonzero bandwidth storage and the Incomplete Cholesky Conjugate Gradient method are adopted. The consequences prove that with the assistance of cross-borehole electric potential combining with borehole-surface electric potential, the project of heavy oil recovery by CO2 steam is feasible and effective.
In-House Developed Kr Estimator: Implemented to Analyze the Sensitivity of Relative Permeability Data to Variations in Wetting Phase Saturation
Authors: Zahoor Muhammad Khurram
Published: February 2012

Reservoir surveillance always requires fast, unproblematic access and solution to different relative permeability models which have been developed from time to time. In addition, complex models sometimes require in-depth knowledge of mathematics for solution prior to use them for data generation. For this purpose, in-house software has been designed to generate rigorous relative permeability curves, with a provision to include users own relative permeability models, a part from built-in various relative permeability correlations. The developed software with state-of-the-art algorithms has been used to analyze the effect of variations in residual and maximum wetting phase saturation on relative permeability curves for a porous medium having very high non-uniformity in pore size distribution. To further increase the spectrum of the study, two relative permeability models, i.e., Pirson's correlation and Brooks and Corey model has been used and the obtained results show that the later model is more sensitive to such variations.
Characteristics of Trace Elements of the No. 6 Coal in the Guanbanwusu Mine, Junger Coalfield, Inner Mongolia
Authors: Xu Jing , Sun Yuzhuang , Kalkreuth W.
Published: February 2012

Forty-four samples of the No. 6 Coal were taken from the Guanbanwusu Mine, Junger Coalfield, Inner Mongolia, in 2009 in order to study trace elements. Twenty-two trace elements of the samples were analysed by ICP-MASS method. The results show that Li, Se and Ag are significantly enriched in the No. 6 coal. Most trace elements are enriched near the roof and floor. The content ratios of Sr and Ba, V and Ni, V and Zn might indicate that the peat swamp of this area during this period is influenced by sea water or in a sea-land transition environment. The enrichment of Li, Se, Ag shows that it formed in a relatively oxidated environment, and ancient water salinity is slightly high. In harmful elements, only Se is significantly enriched. The contents of the other harmful element are low, and do not pose many hazards to the environment. They can be partially removed by physical coal washing.
Effect of Coal Mining on Karst Groundwater in the Fengfeng Coalfield
Authors: Qin Peng
Published: February 2012

Based on geological survey data and detailed geological analysis results, the current article reveals the characteristics effects and role of evolution on karst groundwater caused by coal mining in Fengfeng in Hebei, China. Results indicate that long-term and large-scale mine excretion and excessive groundwater exploitation are major factors that changed the karst groundwater flow field and caused the water level to fall, the water quality to deteriorate and the water resources to decay.
Numerical Assessment of Hybrid Mufflers on a Venting System within a Limited Back Pressure and Space Using Simulated Annealing
Authors: Chiu Min-Chie
Published: February 2012

Although research in finding optimal muffler shapes for low-frequencies noise using reactive mufflers has already been addressed, research into shape optimization of hybrid mufflers that reduce broadband noise within a constrained pressure-drop backpressure is lacking. Therefore, the shape optimization of four kinds of hybrid mufflers using simulated annealing ( SA) in conjunction with the generalized decoupling technique and plane wave theory are presented. Here, a numerical case in eliminating nitrogen venting noise is introduced. The reliability of the SA optimization is also verified using the optimization of muffler A for a pure tone. Moreover, the accuracy of the mathematical models is acceptable with minor deviations between the theoretical and experimental data. Results reveal that the higher backpressure limit will result in a higher acoustical performance. Consequently, the acoustical performance for a hybrid muffler equipped with multiple reactive chambers and one dissipative chamber is superior to that of reactive mufflers.
Influence of the Posture of the Trunk on the Spine Forces during Whole-Body Vibration
Authors: Fritz Martin , Schäfer Klaus
Published: February 2012

Typically drivers of container-bridge cranes are forced to sit with a forward bent upper trunk to control the position and motion of the container. Fork-lift truck drivers incline the upper trunk to the side to look forward or they twist to one side during reversing. Assuming that these inclined postures result in a higher health risk than vibration exposure in the upright sitting posture the forces transmitted in the lumbar spine were assessed by means of a biomechanical model. Under realistic vibration stress the bent postures result in an increase of the compressive and the shear forces. By the enhanced shear forces a displacement of the upper motion segments is prevented. The quantitative relationship between the mean values of the forces and the chest inclination can be sufficiently approximated by regression functions. The increase of the spine forces is the result of the increased muscle forces stabilizing the inclined trunk. On container bridge cranes or fork-lift trucks the typical postures of the drivers result in enhanced spinal forces compared with the upright sitting posture. This effect must be considered in the risk analysis of workplaces with whole-body vibration.
Influence of Driving Speed, Terrain, Seat Performance and Ride Control on Predicted Health Risk Based on ISO 263I-I and EU Directive 2002/44/EC
Authors: Eger Tammy R. , Contratto Michael S. , Dickey James P.
Published: February 2012

Operators of load-haul-dump (LHD) vehicles are commonly exposed to whole-body-vibration (WBV) levels above ISO 2631–1 and EU Directive 2002/44/EC guidelines. WBV was measured at the floor and seat while the same operator drove two LHDs on a controlled test track while driving speed, bucket load, ride control, terrain type, driving task, and seat optimization were varied. Frequency-weighted RMS acceleration was calculated and A(8) values were modeled for six driving scenarios. Vibration exposure was lowest when the LHD was driven at the lowest speed, forward, over smooth terrain, with ride control on and the bucket loaded (0.20 m/s2). The A(8) decreased from 0.84 m/s2 when driving with ride control off, over mixed terrain using all gears, to 0.53 m/s2 when driving with ride control on and an optimized seat. The estimated daily exposure decreased but remained just above the ISO 2631–1 and EU Directive 2002/44/EC guidelines.
Sound Absorption of Hybrid Passive-Active System Using Finite Flexible Micro-Perforated Panels
Authors: Zheng Weiguang , Huang Qibai , Li Shande , Guo Zhongyang
Published: February 2012

Although the vibration effect of micro-perforated panels (MPPs) in passive sound absorption systems has been considered in some studies, research into active systems remains to be accomplished. In this paper, theoretical and experimental studies of hybrid systems using finite flexible MPPs are presented. The impedance of the flexible MPP is derived using the modal analysis solution of the classical plate equation. Then absorption coefficients are predicted based on an electro-acoustic equivalent circuit model. A study of the absorption mechanism of the hybrid system shows that panel vibration can degrade the Helmholtz-resonance absorption performance and bring out panel-type absorption, especially increasing the cavity absorption in systems using impedance-matching conditions. Theoretical results show good agreement with the experiments. It can be seen that flexible the MPP has the potential to dissipate more energy and can be utilized to improve the absorption performance of the hybrid system by appropriately selecting parameters.
The Evaluation of Hand-Arm Vibration Levels in Hand-Held Pneumatic Tools (Rock Drill) by “Pneurop Cagi Test Code” Method
Authors: Forouharmajd Farhad , Nassiri Parvin
Published: February 2012

This paper focuses on measurement and prediction of hand-arm vibration generated when a rock drill is used in stone mines using a B & K vibration meter 2512. In order to evaluate them, we had to locate the hand-arm acceleration levels on the handles of pneumatic hammers while the operator was standing and processing his work. The method of “Pneurop Cagi Test Code” is designed to evaluate noise and vibration propagated by hand-held pneumatic tools. The evaluation of Hand-Arm vibration in hand – held pneumatic tools (Rock drills) used in the lashotor stone mines in Isfahan by the method of the “Pneurop Cagi Test Code” shows methods which are provided to use construction equipment in stone mines under work circumstances. The paper demonstrates measured vibration level values in three directions X, Y, Z for workers while working with equipment, compared to standard values, and a produced by a “Rock Drill” used in the above specifies test method, but reported in only two directions, y and z due to vibration being very low at the x-direction. The found conclusions have shown high values of rms acceleration especially in the Z direction for a wide range of exposure frequencies based on BS EN ISO 5349–1, 2: 2002 standards.
Adsorption on Heterogeneous Surfaces with Simple Topographies
Authors: Centres P.M. , Bulnes F. , Riccardo J.L. , Ramirez-Pastor A.J. , Perarnau M.A.
Published: February 2012

The localized monolayer adsorption of interacting particles onto heterogeneous surfaces has been studied through Monte Carlo simulation in the framework of the lattice–gas model. The substrate was modelled as a collection of finite homotatic patches, each one characterized by an adsorption energy arising from a discrete energy density function. Patches were distributed spatially, either in a deterministic alternate way (ordered topography) or in a non-overlapping random way (random topography). The adsorption process was analyzed by following the behaviour of surface coverage versus chemical potential (adsorption isotherm) and the differential heat of adsorption as a function of the coverage. These quantities depend on the size of the patch as well as on the topological distribution of the patches on the surface. The consequences of these findings are discussed for the determination of the energetic topography of the surface from adsorption measurements.
Trivalent Chromium Ion Removal from Aqueous Solutions Using Low-Cost Zeolitic Materials Obtained from Exhausted FCC Catalysts
Authors: González Maximiliano R. , Pereyra Andrea M. , Basaldella Elena I.
Published: February 2012

The hydrothermal treatment of exhausted FCC catalysts with zeolite was optimized by varying the chemical composition of the synthesis mixture. The zeolitic products obtained were used to evaluate their ability for the capture of Cr(III) cations from aqueous solutions. It was shown that the zeolitic product materials were capable of reducing the Cr(III) ion concentration to values lower than 1.2 ppm. The chromium ion-containing solids were afterwards solidified in cement mortars on which leaching studies of this cation were made. The results obtained showed that the synthesized solids acted as effective Cr(III) ion immobilizers and that their inclusion as additives in cement formulations could provide an environmental friendly disposal procedure.
Textural Characteristics and Energetic Parameters of Activated Carbon Monoliths: Experiments and Monte Carlo Simulations
Authors: Vargas Diana P. , de Oliveira J.C. Alexandre , Giraldo Liliana , Moreno-Piraján Juan Carlos , López R.H. , Zgrablich G.
Published: February 2012

Disc-type activated carbon monoliths were prepared through chemical activation of coconut shell and African palm pits with phosphoric acid at different concentrations, without using any binder. The structures thereby produced were studied experimentally by nitrogen adsorption at 77 K, carbon dioxide adsorption at 273 K and immersion calorimetry in benzene. The experimental data allowed the textural and energetic characterization of the microporous solids to be obtained, viz. BET areas between 752 and 1711 m2/g, micropore volumes between 0.32 and 0.61 cm3/g, ultramicropore volumes between 0.11 and 0.24 cm3/g and immersion enthalpy values between 95.85 and 147.7 J/g. Grand Canonical Monte Carlo (GCMC) simulations were used to analyze the experimental results, providing an interpretation of, as well as a more detailed characterization, of the textural properties, such as the determination of the pore-size distribution (PSD) of each material.
Is the Alexander–Orbach Conjecture Suitable for Treating Diffusion in Correlated Percolation Clusters?
Authors: Cruz Ommar , Hidalgo Ricardo , Alas Salomón , Cordero Salomón , Meraz Laura , Lopez Raúl , Dominguez Armando
Published: February 2012

How does a particle diffuse inside a percolation cluster? This question is of both scientific and practical importance, e.g. in drug-controlled release and vapour adsorption. Diffusion in fractal media is characterized by the fracton dimension, ds. The Alexander and Orbach conjecture indicates that ds = 4/3 for diffusion in classical percolation clusters and, after much research on the subject, it is still provides a very good approximation for ds in the case of uncorrelated percolation cluster structures. However, what happens to the value of ds when a particle is moving inside a correlated percolation cluster? In this work, this problem is studied via Monte Carlo computer simulation. Our results show that the Alexander and Orbach conjecture is not always fulfilled.
Systematic Simulation of Disordered Cylindrical Nanoporous Materials
Authors: Gil-Cruz Ubaldo , Cordero-Sánchez Salomón , Villegas-Cortez Juan , Villalobos-García Rafael
Published: February 2012

This paper describes a simple method, based on the Dual Site–Bond Model, for constructing disordered cylindrical porous substrata. Heterogeneity is accounted for by allowing the presence of variable cross-sectional areas along the length of the pore tubes forming the solid. The degree of heterogeneity is easily controlled with overlapping between the pore-size distributions of pore cavities and pore necks. Some simulated materials with different textural properties are presented. An analysis of the texture of the generated structures, together with their nitrogen adsorption characteristics, has been carried out and is discussed.
A Review of Woven Structures with Focus on Reciprocal Systems - Nexorades
Authors: Baverel O. , Larsen O. Popovic
Published: February 2012

The main aim of this paper is to present the different types of load-bearing woven systems that stand by friction or with the use of a locking device. A review of the different types of systems has been done and an attempt of classification has been proposed. The paper focuses on the different types of elements that can be used to create reciprocal systems or nexorades. Configurations with elongated, ring, tile and block elements are shown. The different parameters that define such structures are also presented. Although the description of the parameters is quite easy for simple construction, a broader approach is still needed to be done for more complex configurations.
Frames Designed by Leonardo with Short Pieces. An Analytical Approach
Authors: Sánchez José , Escrig Félix
Published: February 2012

This paper deals with the analysis with actual mathematical tools of some structural proposals done by Leonardo in his notebooks. At difference of other subjects such as the Fly of Birds or Treatise of Painting, he never made his sketches to establish a coherent treatise on structures although he consumed a lot of pages analyzing constructional patterns to build bridges, roofs and floors a well vas beams, strings and mechanisms. May be he never constructed his proposals, but them are designed as if it would necessary to define minimal details. A particular subject contained in his notebooks are concerning to great span structures built with short elements. We try to proof the validity of these proposals.
Analytical Investigations on Elementary Nexorades
Authors: Sénéchal B. , Douthe C. , Baverel O.
Published: February 2012

Nexorades or reciprocal frames can be seen as a practical way to reduce the complexity of connections in spatial structures by connecting reciprocally the members by pairs. This reduction of the technological complexity of the connections is however replaced by a geometrical complexity due to numerous compatibility constraints. The purpose of this article is to make explicit these constraints for elementary structures and to solve analytically the resulting system of equations. Applications to regular polyhedrons are presented and a practical realization (a 3 m high dodeca-icosahedron) is shown. In the brief conclusion, perspectives for complementary analytical developments for spatial structures are drawn forth.
Geometrical Description and Structural Analysis of a Modular Timber Structure
Authors: Nabaei Seyed Sina , Weinand Yves
Published: February 2012

The ambitious goal of the ongoing research at IBOIS, the Laboratory of timber constructions at the Ecole Polytechnique Fédérale de Lausanne (EPFL) is to develop a next generation of timber constructions made out of innovative timber-derived products, through applying textile principles on the building scale. The presented structure is a modular composition of timber folded panels, notably demonstrates an example of applying the geometric techniques used to produce modular patterns and lattices to timber construction context. Effectively, it is shown that complex space structures can be designed using simple connection technology between elements. Moreover, by taking advantage of advanced CAM process, complex planar timber elements are cut in large scale and assembled with high precision as for the prototype of the structure presented in this paper. Here, the basic module is consisted of two mutually supporting timber folded panels which are slipped in, consecutively, along their cuts, to build up an arch. The folding concept corresponds to a new family of reciprocal frame structures, where instead of traditional linear elements, mutually supported planar members are employed. The inter-module connection's stability is provided by contact boundary condition over the slide joints. The fundamental mechanical properties of the structure are examined using Finite Element Method and considering the nonlinear contact boundary condition. The static behavior is studied under the self-weight load case as well as the modal dynamic response. According to analysis results, and by aid of a CAD parametric model, structural and geometrical alternatives are proposed to improve the structural performance. A prototype based on this geometric principal has been fabricated and assembled to explore feasibility of the concept in the building scale.
Behavior of a Simple Nexorade or Reciprocal Frame System
Authors: Gelez Simon , Aubry Simon , Vaudeville Bernard
Published: February 2012

Among the family of space structures is a typology called nexorades or reciprocal frame structures. Nexorades can have various configurations and shapes. This article focuses on a simple configuration to obtain results that are easy to read and communicate. The aim is to get a better understanding of the structural behavior of nexorades to facilitate their design. Two analytical methods are proposed to calculate the bending resistance and the stiffness of a nexorade. The influence of the connections between members on the structural behavior and the robustness is studied. A comparison is made with flat grids.
Workshop « Ateliers Design » : « Nexorades, Facing an Emergency Situation »
Authors: Gelez Simon , Saby Victoire
Published: February 2012

Nexorades, or Reciprocal frame systems, work according to a simple concept and are easily constructible. It was a perfect topic for a one week workshop. The geometrical complexity of nexorades was undertaken thanks to 1:5 mochups that were used to achieve form-finding. It enabled students to build full-scale structures to face defined emergency situations with specific requirements.
Broadband Combustion Noise Simulation of Open Non-Premixed Turbulent Jet Flames
Authors: Mühlbauer Bernd , Ewert Roland , Kornow Oliver , Noll Berthold
Published: February 2012

Numerical broadband combustion noise simulations of open non-premixed turbulent jet flames applying the Random Particle-Mesh for Combustion Noise (RPM-CN) approach are presented. The RPM-CN approach is a hybrid Computational Fluid Dynamics/Computational Aeroacoustics (CFD/CAA) method for the numerical simulation of turbulent combustion noise, based on a stochastic source reconstruction in the time domain. The combustion noise sources are modeled on the basis of statistical turbulence quantities, for example achieved by a Reynolds averaged Navier-Stokes (RANS) simulation, using the Random Particle-Mesh (RPM) method. RPM generates a statistically stationary fluctuating sound source that satisfies prescribed one- and two-point statistics which implicitly specify the acoustic spectrum. Subsequently, the propagation of the combustion noise is computed by the numerical solution of the Linearized Euler Equations (LEE). The numerical approach is applied to the DLR-A, the DLR-B and the H3 flames. The open non-premixed turbulent jet flames differ in the mean jet exit velocity, therefore in their respective Reynolds number, and in the fuel composition. Computed radial profiles of the reacting flow field are compared to experimental data and discussed. Computed sound pressure level spectra of the DLR-A and DLR-B flames and acoustic intensity level spectra of the H3 flame at different microphone locations are presented and compared to measurements.
On Sound Generation by Moving Surfaces and Convected Sources in a Flow
Authors: Campos L.M.B.C. , Lau F.J.P.
Published: February 2012

The theory of sound generation by surfaces in arbitrary motion is presented, with two generalizations relative to the Ffowcs-William Hawkins (FWH) equation: (i) it allows for the presence of a steady, non-uniform potential flow of low Mach number; (ii) it includes the effects on the radiation field of reflections from solid surfaces, e.g. these which cause non-uniformity of the flow. The final result is a generalization of the Kirchhoff integral with: (i) a retarded time modified by sound convection by the mean flow; (ii) position coordinates of observer and source modified to account for the presence of the obstacles which reflect sound waves and cause the mean flow to be non-uniform. An alternative generalization of the Kirchhoff integral is presented for sources in arbitrary motion in an uniform mean flow with unrestricted Mach number. The two generalized forms of the Kirchhoff integral also apply to convected sources of sound, such as the turbulence noise associated with vorticity and the entropy noise due to convected fluid inhomegeneities. The two noise sources are shown to be dominant at low Mach number, relative to other noise sources present in an inhomogeneous potential flow with unrestricted Mach number. In the latter case applies the (i) inhomogeneous high-speed wave equation, that includes as particular cases the (ii) convected and (iii) classical wave equations. The latter two (ii–iii) are obtained from (α) the Laplace equation using the retarded time. All three (i–iii) are obtained by two more distinct methods: (β) elimination among the equations of fluid mechanics for the stagnation enthalpy as acoustic variable; (γ) an acoustic variational principle for the acoustic potential in a steady homentropic non-homogeneous potential mean flow with unrestricted Mach number.
Analysis of the Helishape Descent Database with Regards to Blade-Wake Interaction Noise
Authors: Vitsas Panagiotis A. , Menounou Penelope
Published: February 2012

Helicopter rotor Blade Wake Interaction (BWI) noise is known to be significant during take-off and level flight. Less attention has been given to descent flight conditions, where Blade Vortex Interaction (BVI) noise is dominant. The present study investigates BWI noise in descent flight conditions by analyzing the HELISHAPE descent case database. Through signal analysis of both acoustic waveforms and spectra, the rotor azimuthal region responsible for BWI noise is localized and the dominance of BVI noise in the BWI frequency region is shown. Coherence analysis of the blade pressure data indicate significant chordwise coherence in the 3 to 4 Strouhal number range and absence of acoustic dipoles in the BWI frequency range. Comparison with analysis of a swept-back blade-tip database showed that blade-tip shape does not affect BWI noise. The findings of this study support BWI prediction models based on Amiet's theory and suggest that BWI noise can be ignored for predictions of rotor noise in descent flight conditions.
Decoding Culture Parametrically: Digital Tea House Case Studies
Authors: Ko Kaon , Liotta Salvator-John
Published: February 2012

This paper reviews the Digital Tea House, a workshop held at the University of Tokyo with the aim to build three pavilions for hosting tea ceremony. As first attempts on cultivating formal innovations resulting from digital design process applied to construction of tea houses, the works convey that parametric design can be a mechanism through which architects are able to produce new images of a tea house and renew its conceptual meanings, and that it can be a tool to retain architecture convergent with cultural values. The authors analyze issues addressed in the workshop that range from applications of computational design, interpretations of tradition, structural stability, to solutions for quick physical materialization within limited time and budget. This paper clarifies the following: First, that parametric processes are not contradictory to traditional cultural principles; and second, how traditional elements of the tea house were decoded and formally reinterpreted through parametric designs.
Energy-Oriented Design Tools for Collaboration in the Cloud
Authors: Toth Bianca , Salim Flora , Burry Jane , Frazer John , Drogemuller Robin , Burry Mark
Published: February 2012

Emerging from the challenge to reduce energy consumption in buildings is the need for energy simulation to be used more effectively to support integrated decision making in early design. As a critical response to a Green Star case study, we present DEEPA, a parametric modeling framework that enables architects and engineers to work at the same semantic level to generate shared models for energy simulation. A cloud-based toolkit provides web and data services for parametric design software that automate the process of simulating and tracking design alternatives, by linking building geometry more directly to analysis inputs. Data, semantics, models and simulation results can be shared on the fly. This allows the complex relationships between architecture, building services and energy consumption to be explored in an integrated manner, and decisions to be made collaboratively.
Understanding Visual Scripts: Improving Collaboration through Modular Programming
Authors: Davis Daniel , Burry Jane , Burry Mark
Published: February 2012

Modularisation is a well-known method of reducing code complexity, yet architects are unlikely to modularise their visual scripts. In this paper the impact that modules used in visual scripts have on the architectural design process is investigated with regard to legibility, collaboration, reuse and design modification. Through a series of thinking-aloud interviews, and through the collaborative design and construction of the parametric Dermoid pavilion, modules are found to impact the culture of collaborative design in architecture through relatively minor alterations to how architects organise visual scripts.
Biofeedback and Virtual Environments
Authors: Champion Erik , Dekker Andrew
Published: February 2012

This paper explains potential benefits of indirect biofeedback used within interactive virtual environments, and reflects on an earlier study that allowed for the dynamic modification of a virtual environment's graphic shaders, music and artificial intelligence, based on the biofeedback of the player. The aim was to determine which augmented effects aided or discouraged engagement in the game. Conversely, biofeedback can help calm down rather than stress participants, and attune them to different ways of interacting within a virtual environment. Other advantages of indirect biofeedback might include increased personalization, thematic object creation, atmospheric augmentation, filtering of information, and tracking of participants' understanding and engagement. Such features may help designers create more intuitive virtual environments with more thematically appropriate interaction while reducing cognitive loading on the participants. Another benefit would be more engaged clients with a better understanding of the richness and complexity of a digital environment.
Designing Architectural Morphing Skins with Elastic Modular Systems
Authors: Khoo Chin Koi , Salim Flora , Burry Jane
Published: February 2012

This paper discusses the issues of designing architectural skins that can be physically morphed to adapt to changing needs. To achieve this architectural vision, designers have focused on developing mechanical joints, components, and systems for actuation and kinetic transformation. However, the unexplored approach of using lightweight elastic form-changing materials provides an opportunity for designing responsive architectural skins and skeletons with fewer mechanical operations. This research aims to develop elastic modular systems that can be applied as a second skin or brise-soleil to existing buildings. The use of the second skin has the potential to allow existing buildings to perform better in various climatic conditions and to provide a visually compelling skin. This approach is evaluated through three design experiments with prototypes, namely Tent, Curtain and Blind, to serve two fundamental purposes: Comfort and Communication. These experimental prototypes explore the use of digital and physical computation embedded in form-changing materials to design architectural morphing skins that manipulate sunlight and act as responsive shading devices.
Development of the Seed Scattering System for Computational Landscape Design
Authors: Takenaka Tsukasa , Okabe Aya
Published: February 2012

This paper proposes a computational landscape design method, called the Seeds Scattering system (SS system), that was developed by the AnS Studio to carry out the Sony forest project in Japan. This method enables us to manage various environmental conditions in design processes, to design ‘natural’ in urban areas, (i.e., people perceive a forest in an urbanized area as if it is natural although the forest is not genuinely natural). First, this paper discusses the limitations of the conventional method of landscape design. In Section 3 to 4, we describes the SS system together with the design process of the project. In Section 5, we present the system from a different perspective, that is, as a method for satisfying social requirements to gain human appreciation. The designer's role in this system is not to manipulate geometries or compositions of tree groupings but to design the fundamental rules that underlie them. As a result, the designer can create a landscape in an interactive manner, thereby producing one that inherently belongs to its site.
Selective Jamming: Digital Architectural Design in Foundation Courses
Authors: Roudavski Stanislav
Published: February 2012

This article considers how the concepts and practice of digital architectural design can influence early architectural education. The article approaches this topic through one example, the Virtual Environments course – a constituent of the Bachelor of Environments program at the University of Melbourne. The institutional remit of this course is to introduce first-year students to the roles of design representation. However, recently, the course developed to encompass these pragmatic educational aims and began to question canonical attitudes towards architectural education and practice. At the core of this course are the notions, methods and skills of digital architectural design, understood not as a stylistic option or as a novel paradigm, but as a catalyst for creativity, experimentation, critical thinking and the sustained growth of creative communities.
BIM's Seven Deadly Sins
Authors: Holzer Dominik
Published: February 2012

This paper aims at exposing seven prevailing problems that have emerged in the uptake of Building Information Modelling (BIM) in design practice. The paper provides a reality check between an idealistic view on BIM and the way it is currently applied in daily use. In order to reflect on the issues at hand, the author draws from three years of doctoral research in multidisciplinary design collaboration, followed by more than two years experience as Design Technology director in a large scale architecture practice. In addition to the above, his current role as the chair of the BIM and IPD Steering Group of the Australian Institute of Architects and Consult Australia exposes the author to a broad range of cultural implications of BIM. The findings presented here illustrate that, despite major advances in the development of BIM, there are predominantly cultural roadblocks to its implementation in practice.
Magnetism and electronic transport in (Ni, Cu)2 MnSn Heusler alloys under ambient and elevated pressures
Authors: Bose S. , Kudrnovský J. , Drchal V.
Published: February 2012

The electronic properties, exchange interactions, Curie temperatures and transport properties of random quaternary Heusler alloys (Ni, Cu)2MnSn are studied by means of density-functional calculations over the entire range of dopant concentration. Results agree qualitatively as well as quantitatively with the available experimental data. The residual resistivity is found to obey the Nordheim rule, indicating weak-scattering regime. The temperature-dependent spin-disorder resistivity is found to be described well via the disordered model of local moments. Effect of pressure on the Curie temperature and the resistivity is also explored.
Design optimization of bonded steel-concrete composite beams
Authors: Luo Yangjun , Li Alex
Published: February 2012

Bonded steel-concrete is one new type composite structure in civil engineering domain. Generally, for steel-concrete composite structures, the steel beam and the concrete are connected by means of shear connectors. This work consists in analyzing the design optimization of the steel-concrete composite beam connected by adhesives instead of metal connectors. The principal parameters, including elastic modulus of adhesive, the adhesive layer thickness, the bonding strength and the bonding area, which influence the mechanical behaviours of the bonded steel-concrete composite structures, have been investigated. Finally, an example of design optimization of a single span adhesive bonded steel-concrete composite beam is proposed.
Monte Carlo simulation of defects in hard-sphere crystal grown on a square pattern
Authors: Mori Atsushi , Suzuki Yoshihisa , Matsuo Shigeki
Published: February 2012

Monte Carlo simulations of hard-sphere (HS) crystal grown on a square patterned wall under gravity have been performed. While previous simulations were performed with step-wise controlled gravity, in the present simulations constant gravity has been applied from the first. In the case in which a flat wall is used as the bottom wall, if a large gravity is suddenly applied, the system does polycrystallize. On the other hand, in the present simulations, despite the sudden application of gravity, the system has not polycrystallize. Crystalline nucleation on the square pattern and successive crystal growth upward are suggested to overcome the homogeneous nucleation inside and result in. Defect disappearance, which has been essentially the same as that for the case with step-wise controlled gravity, has also observed for the present case. The characteristic of the square patterned bottom wall simulation with a large horizontal system size has been existence of triangular defects suggesting stacking tetrahedra.
Ball milling of jute fibre wastes to prepare nanocellulose
Authors: Baheti V. , Abbasi R. , Militky J.
Published: February 2012

The objective of this work was to use the spinning waste in form of short fibres for the preparation of nano size fillers in nanocomposite applications. The present paper concerns with the jute fibres as the source to produce nanocellulose by high energy planetary ball milling process and its potential applications as fillers in biodegradable nanocomposite plastics used in automotives, packaging and agriculture applications. Influence of various milling conditions like nature of milling (i.e. dry or wet), milling time and ball size are studied on the particle size distribution and morphology of jute nanoparticles obtained. Wet milling in the deionised water resulted into particle size refinement below 500 nm with narrow size distribution after 3 hours of milling at the cost of small amount of contaminations introduced from milling media.
Effect of internal hydrophobation, silica fume and w/c on compressive strength of hardened cement pastes
Authors: Baghban M. , Hovde P. , Jacobsen S.
Published: February 2012

Internal hydrophobation by adding hydrophobic agents during the mixing process is a method for reducing water permeability of cement based materials. It can be used as an alternative to other methods such as reducing water cement ratio (w/c) or using silica fume (SF). However, it may affect other properties of cement based materials such as compressive strength. In this paper the results of an experimental study on compressive strength of different hcps with main variables w/c, SF and hydrophobic agents are presented. Rapeseed oil and alkyl alkoxysilane were selected as hydrophobic agents. Although, a low dosage of hydrophobic agents can be more effective than lowering w/c or adding SF in reducing water permeability, an obvious reduction was observed in compressive strength by this way of internal hydrophobation compared to the other above mentioned methods. Different reasons such as lower hydration degree, chemical reactions of hydrophobic agents and non-uniform distribution of hydrophobic materials in the hcp could have resulted in lower compressive strength of hydrophobed samples. Using other types of hydrophobic agents or impregnation after the curing process can be other alternatives which would have less effect on compressive strength.
Influence of concrete shrinkage and creep on structural characteristics of precast and prestressed concrete shells
Authors: Sossou G.
Published: February 2012

The actual concern for structural engineers is the failure of the structural material to meet the design safety and the safe service life of large span and wide floor space buildings. The main idea in this present report reflects the combination of the economical use of construction materials with the long and durable safe service life to cover large floor spaces, using precast and prestreseed concrete shell structural members. This paper describes the present ongoing numerical and experimental analysis model used to determine the structural long duration flexural and nonlinear deformation characteristics of reinforced precast elliptical paraboloid concrete shell elements, prestressed in both directions. Horizontal precast and prestressed edge beams supported on prestressed columns are provided to support the longitudinal edges of the shells. This present study has been based on nonlinear differential equations of the concrete matrix creep theory which reflects the correlation between the matrix stress and strain by its modulus of elasticity and on the well-known geometrical preconditions of the theory of elasticity concerning thin plates with small flexural deformations. For structural and crack predictions, the well-known virtual work principles have been used to estimate (a) transient bi-directional strains due to the matrix creep and shrinkage, (b) the resulting time-dependent bi-directional stress redistribution, as well as (c) bi-directional displacement variations in the structural shell elements and finally (d) bi-directional pre-stressing losses in the pre-stressed high yield tendons. The concrete shear stresses have been evaluated by the well-known principle of Juravskiy. A series of original test experiments with once evaluated strength parameters has been planned to be successfully used to provide encouraging support for the numerical evaluations.
Integrating Sensor and Motion Models to Localize an Autonomous AR.Drone
Authors: Dijkshoorn Nick , Visser Arnoud
Published: February 2012

This article describes a method to develop a generic approach to acquire navigation capabilities for the standard platform of the IMAV indoor competition: the Parrot AR.Drone. Our development is partly based on simulation, which requires both a realistic sensor and motion model. The AR.Drone simulation model is described and validated. Furthermore, this article describes how a visual map of the indoor environment can be made, including the effect of sensor noise. This visual map consists of a texture map and a feature map. The texture map is used for human navigation and the feature map is used by the AR.Drone to localize itself. To do so, a localization method is presented. An experiment demonstrates how well the localization works for circumstances encountered during the IMAV competition.
Reliable Force Predictions for a Flapping-Wing Micro Air Vehicle: A “Vortex-Lift” Approach
Authors: Thielicke W. , Kesel A.B. , Stamhuis E.J.
Published: February 2012

Vertical and horizontal force of a flapping-wing micro air vehicle (MAV) has been measured in slow-speed forward flight using a force balance. Detailed information on kinematics was used to estimate forces using a blade-element analysis. Input variables for this analysis are lift and drag coefficients. These coefficients are usually derived from steady-state measurements of a wing in translational flow. Previous studies on insect flight have shown that this method underestimates forces in flapping flight, mainly because it cannot account for additional lift created by unsteady phenomena. We therefore derived lift and drag coefficients using a concept for delta-wings with stably attached leading-edge vortices. Resulting lift coefficients appeared to be a factor of 2.5 higher than steady-flow coefficients, and match the results from previous (numerical) studies on instantaneous lift coefficients in flapping flight. The present study confirms that a blade-element analysis using force coefficients derived from steady-state wind tunnel measurements underestimates vertical force by a factor of approximately two. The equivalent analysis, using “vortex-lift” enhanced coefficients from a delta-wing analogue, yields very good agreement with force balance measurements, and hence seems to be a good approximation for lift-enhancing flow phenomena when modelling flapping flight.
Wing Flexibility Effects in Clap-and-Fling
Authors: Percin M. , Hu Y. , van Oudheusden B. W. , Remes B. , Scarano F.
Published: February 2012

The work explores the use of time-resolved tomographic PIV measurements to study a flapping-wing model, the related vortex generation mechanisms and the effect of wing flexibility on the clap-and-fling movement in particular. An experimental setup is designed and realized in a water tank by use of a single wing model and a mirror plate to simulate the wing interaction that is involved in clap-and-fling motion. The wing model used in the experiments has the same planform with the DelFly II wings and consists of a rigid leading edge and an isotropic polyester film. The thickness of the polyester film was changed in order to investigate the influence of flexibility. A similarity analysis based on the two-dimensional dynamic beam equation was performed to compare aeroelastic characteristics of flapping-wing motion in-air and in-water conditions. Based on the experimental results, the evolution of vortical structures during the clap-and-peel motion is explained. The general effects of flexibility on vortex formations and interactions are discussed. It was observed that the flexibility affects the behavior and orientation of the vortices in relation to the deformation of the wing and interaction with the mirror plate.
Equilibrium Transition Study for a Hybrid MAV
Authors: Itasse Maxime , Moschetta Jean-Marc , Ameho Yann , Carr Ryan
Published: February 2012

Wind tunnel testing was performed on a VTOL aircraft in order to characterize longitudinal flight behavior during an equilibrium transition between vertical and horizontal flight modes. Trim values for airspeed, pitch, motor speed and elevator position were determined. Data was collected by independently varying the trim parameters, and stability and control derivatives were identified as functions of the trim pitch angle. A linear fractional representation model was then proposed, along with several methods to improve longitudinal control of the aircraft.
Application of Electro-Active Materials to a Coaxial-Rotor NAV
Authors: Thipyopas C. , Sun A. B. , Bernard E. , Moschetta J.-M.
Published: February 2012

A new Nano Air Vehicle (NAV) configuration based on a coaxial nano rotor has been studied by ISAE. The coaxial rotor provides the thrust necessary for hovering and low speed translation flight. The major design challenge for rotary-wing NAVs is related to the difficulty of miniaturizing complex mechanisms such as a rotor cyclic pitch swashplate commonly used for controlling helicopters. The use of actuators made of smart materials is believed to allow for controlling rotary-wing NAVs in a much simpler and lighter way. The multidisciplinary subject of this complete system is separated into few parts. The studies of each subject are individually conducted before integrated in the future in order to optimize the global system. Those studies which are being carried out are shortly described in this paper.