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As is known to all, the cable corridor is one of the most important projects in China. In this paper, the fire temperature field distribution of L-type corridor under the condition of different fire source location height is studied through numerical simulation. When the heat release rate of the ignition source is 250 kW and longitudinal wind speed is fixed 0.5 meters per second, the temperature changing rule of the inflection point of L-type corridor is discussed. Furthermore, the temperature prediction formula is established based on the height of the ignition source at different stages according to the fire situation. Combined with the results of these studies, the paper shows that there is obvious "smoke accumulation effect" in L-type cable corridor. [ABSTRACT FROM AUTHOR]

Incremental bulk deformation processes have traditionally been difficult to simulate. This paper will argue that, despite advances in computation and software, they remain difficult to model. The main reason for this is the shortage of ideas on what is the real objective of FE modelling for such processes. Even a very detailed model and data obtained in simulation does not give answers to the main question - how to optimise the process parameters? High computational time and volume of information only aggravate the situation. All modern mathematical techniques of dimensionality reduction (such as POD/PGD) lose their power when the priorities and acceptable compromises of modelling are not clear. This paper tries to use a large volume of available experimental and modelling experience to illustrate this problem and look for possible break-through directions. [ABSTRACT FROM AUTHOR]

The paper considers the questions of experimental research of deformation of elastic elements regarding the foil gas dynamic bearings. This research is required to check the adequacy of developed theoretical basics and the applicability to the real operation of a high-speed rotor. The paper presents the description of a test rig, the choice of the controlled and measured parameters, the experimental set up of the systems of control and measurement; and identifies the range of controlled parameters deviation. The paper also features schemes and photos of original measurement system, which include a mechanical part and the data acquisition system. The data acquisition system is based on an ADC by National Instruments and inductive proximity sensors. The software developed in LabVIEW is used as an instrument of experimental data registration. The test results have been compared to the numerical results of the mathematical modeling. [ABSTRACT FROM AUTHOR]

In industrial applications, most of fluids have non-Newtonian fluid characteristics. It is of great significance to the economic development and energy consumption reduction to study the heat transfer of non-Newtonian power law fluid. In this paper, the heat transfer of non-Newtonian power law fluid in pipes with different cross sections are studied. The mathematical model and physical model of the non-Newtonian fluid are briefly introduced first, and the physical model is divided by the structured mesh. Then the numerical simulation of the laminar heat transfer of non-Newtonian fluid in different cross sections is carried out. On the basis of discussing the distribution of temperature field, many parameters which have influenced on the temperature field and the heat transfer is analyzed in this paper, such as tube shape, the power-law index ( n ) the Peclet number ( Pe ) and so on. The results show that the heat transfer characteristics of non-Newtonian fluid are related to the parameters we mentioned. [ABSTRACT FROM AUTHOR]

This paper designs and discusses a Micro-Plate Loop Heat Pipe which is suitable for the heat dissipation of various electronic chips, discusses and explains details of the loop heat pipe components. This paper also discovers the reliable sintering temperature and thermal insulation time for a sintering porous capillary wick which is made up of nickel powder using the method of cold pressure forming and sintering with vacuum protection. It can lay a solid foundation for the development of efficient Micro-Plate Loop Heat Pipe equipment. It is also important for circular heat pipe further research and development. [ABSTRACT FROM AUTHOR]

It is a hot topic whether the choice of heating supply is necessary and what is the most suitable form of heating system for hot summer and cold winter regions. Apparently, the difference of climate and building envelope makes it a complex problem, which cannot rely on the northern heating measures directly. At the same time, the form of building envelope is closely related to energy consumption and indoor thermal environment. Thus, this paper looked at the importance of different thickness of building external insulation for residential building in Chongqing. This paper discussed the thickness of building external insulation in Chongqing based on the intermittent heating system, which used Dest to draw the conclusion. Economic and technical analyses were also carried out in order to find the balance point between the growth of cost and the amount of energy saving, due to the different form of building envelopes. [ABSTRACT FROM AUTHOR]

One of the simplest ways of digital image forgery is a copy-move attack. The copy-move process consists of three stages: copy selected image fragment from one place, transform it using some image processing algorithm and paste it to another place of the same image. Two main approaches to copy-move detection exist nowadays: feature-based and hash-based. Most of the algorithms are developed according to the feature-based approach, whereas the hash-based approach is used only for plain copy-move detection (when the copied image fragment is not transformed). However, the main advantage of hash-based algorithms is low computational complexity. In this paper, we propose a new hash-based copy-move detection algorithm that can be applied to transformed duplicates detection due to a special preprocessing procedure. This procedure implements initial image transformation to incorporate the changes (affine transforms are not considered in this paper), produced by a transform algorithm on the second stage. Several preprocessing procedures are compared during experiments: image intensity range reduction, gradient calculation, expansion in orthonormal basis, adaptive linear contrast enhancement and local binary pattern. [ABSTRACT FROM AUTHOR]

The aim of this paper is to extend canard constructing method given by J. Ginoux, J. Llibre, and L. Chua [1,2]. In this paper, we consider a black swan construction for three-dimensional autocatalator model using modified flow curvature method. [ABSTRACT FROM AUTHOR]

This paper presents information on the content and resources of the internationally certified Master’s program “Mathematical Modeling and Information Technologies in Photonics” in the field of Applied Mathematics and Physics. The paper investigates scientific achievements of the academic staff, peculiarities of courses currently held, opportunities of available facilities and resources, and prospects for the Master’s worldwide research activities. [ABSTRACT FROM AUTHOR]

This paper presents a framework for nonlinear system identification of civil structures using sparsely measured dynamic output response of the structure. Using a sequential maximum likelihood estimation (MLE) approach, the unknown FE model parameters, the measurement noise variances, and the input ground acceleration time histories are estimated jointly. This approach requires the computation of FE response sensitivities with respect to the unknown FE model parameters (i.e., FE parameter sensitivities) as well as the FE response sensitivities with respect to the values of the input ground acceleration at every time step (i.e., FE input sensitivities). The FE parameter and input sensitivities are computed using the direct differentiation method (DDM). The presented output-only nonlinear FE model updating method is validated using the numerically simulated seismic response of a realistic three-dimensional five-story reinforced concrete building structure. The simulated building responses to a horizontal bi-directional seismic excitation is contaminated with artificial measurement noise and used to estimate the unknown FE model parameters characterizing the nonlinear material constitutive laws of the reinforced concrete, as well as the root mean square of the measurement noise at each measurement channel, and the full time history of the seismic base acceleration. The method presented in this paper provides a powerful framework for structural system and damage identification of civil structures, when the input excitations are not measured, are partially measured, or the measured input excitations are erroneous. [ABSTRACT FROM AUTHOR]

Thermal output of the piping system is investigated. The system was formed from a tube of circular section, made of multilayer polyethylene - aluminum. It was subsequently wound into a planar spiral. The paper contains the calculation of the thermal output by a mathematical model, which replace the real model. The experimental measurements were measured with a variable distance winding. The paper compare heat output results with experimental measurements. [ABSTRACT FROM AUTHOR]

The paper introduces the neural model for assessing the value of social capital. Algorithms proposed in the literature for such estimations were discussed and their fundamental constraints were indicated. The main purpose of the research was to develop the most efficient model for such estimations. It involved defining and verifying such factors as: number of neurons, activation functions, learning algorithms, error function, etc. The empirical studies allowed also identifying variables most significantly affecting the value of social capital. The paper concludes with discussion about potential users of proposed method and proposals for further research. [ABSTRACT FROM AUTHOR]

The paper takes design of the tenth China (Wuhan) International Garden EXPO as an example, concludes the development direction of low-carbon parks in China, and highlights the use of sponge city and green architecture design. Firstly, the paper introduces overview and design cases of the EXPO. Then, the paper elaborates the goals of low-carbon design. It describes the low-carbon technical application of the EXPO park, i.e. comprehensive design based on overall coordination and avoidance of conflicts, intelligent city planning, processing technology of existing landfill, conducting onsite balance work for earthwork, water recycling system planning, building ecological low-carbon architecture, building and repairing of ecological darning bridge, etc. Besides, the park also adopts design principle of sponge city. As an urban oasis, Wuhan International Garden EXPO darns the divided city; as a public space, it provides an ecological space for more citizens to visit and enjoy. Its example is a reference for design of low-carbon parks in China in the future. [ABSTRACT FROM AUTHOR]

Selecting materials that are energy efficient over their life cycle at the early stage of a design is dependent upon numerous parameters that make determination of all their impacts on the environment difficult. Choice of thermal insulation options for a building's external walls significantly affects its life cycle energy demands. However, the accurate impact analysis of different insulation options from a life cycle energy assessment (LCEA) viewpoint is influenced by numerous interrelated parameters and is generally too complex for designers to determine in the early material selection stage of design. The aim of this paper is to highlight this complexity by using the example of an evaluation of the LCEA of 18 different forms of thermal insulations that vary in type and thickness for a multi-storey residential building in Sydney, Australia. The sensitivity of the results to the Window to Wall Ratio (WWR), as an another effective variable on the building's operational energy demands, is then analysed. The study indicates that different thermal insulation options of external walls have a marginal impact on the building cooling energy demands in Sydney's climatic zone, whereas they significantly affect the heating energy demands. In addition, changing of insulation options produce significant increases in the embodied energy. The impact of various WWRs on the building's operational energy changes the result of the optimum and the least efficient choices among the 18 insulation options. Overall, the example highlights that it is not possible to quantify all the effective parameters in selecting materials in terms of designing an energy efficient building through its life cycle. This paper is part of a larger research project attempting to simplify the LCEA and enable designers to identify the most effective variables on a building's life cycle energy demand when selecting materials at the early design stage. [ABSTRACT FROM AUTHOR]

In the paper we consider the problem of identification of large-scale interconnected systems. Accurate models of complex nets are needed especially for optimal control in production and transportation systems. The specifics lay in the fact that individual elements cannot be disconnected and excited by arbitrary input processes for identification purposes. Moreover, structural interactions cause correlations between interaction signals. In particular, any output random disturbances can be transferred into the other inputs. It leads to cross-correlation problems, very difficult from the effective modelling point of view. First attempts made in 1980's were limited to static linear blocks, and in practice the results were rather devoted to linear dynamic systems working in steady state. In this paper we generalize the approach for components, which are both dynamic and nonlinear. All blocks are represented by two-channel Hammerstein systems (used e.g. in modelling of real heating processes). The least squares estimate is applied to identify unknown parameters of a system. The parameters of particular elements are obtained in singular value decomposition procedure. The algorithm as a whole is illustrated in simple simulation example. [ABSTRACT FROM AUTHOR]

This paper is the part of research aimed at creating robotic manipulator controlled by means of Brain-Computer Interface for improving household self-reliance of persons with disabilities and expanding the scope of their activity. The robotic manipulator gives possibility of self-fulfillment in basic household functions, s.a. drinking, eating, facial hygiene. The paper presents a mathematical model of the kinematics of the robotic manipulator. The solution of the forward and inverse kinematics problems based on the geometric method are given and obtained in MATLAB for the 5DOF manipulator. [ABSTRACT FROM AUTHOR]

Bridges represent a key part of infrastructure, playing a critical role in emergency response and post-event reconstruction. In this context, it is important for bridges to be able to survive both ground shaking and the effects of tsunamis. This paper focuses on numerically modeling bridge loading due to tsunamis. Although several studies have addressed the effect tsunami loads on bridges, few have examined the influence of debris carried by the tsunami. These problems involve complex contact interactions between solids and fluids that are not easily accommodated using typical fluid-oriented or solids-oriented numerical frameworks. In this paper the material point method (MPM) is used to address fluid and solid (moving and stationary) interactions with emphasis in evaluating demands on bridge superstructures by tsunami-driven debris. Two parametric studies have been conducted in this study. The first is aimed at understanding the influence of the contact area and the eccentricity of impact on the impact forces. The results show that the effect of these two factors are reduced with an increase in longitudinal length of the solid object. The second part of the study tries to evaluate the difference between tsunami driven debris impact loads and in-air debris impact loads. The results indicate that tsunami driven debris impacts tend to be larger by upto 35% compared to only in-air impact forces calculated using empirical equations. [ABSTRACT FROM AUTHOR]

In this paper a new viscosity model is proposed in order to predict the viscosity of the nanofluids in order to bridge the gap on this issue. The effective viscosity expression proposed in this paper is based on the regression analysis of a number of carefully selected published papers which covers theoretical, experimental and numerical results. Compared with the other theoretical models that are available in literature, the presented model has a good accuracy and reliability. The proposed model has been tested in 3D horizontal pipe and the results with Nusselt number show good agreement with available data. The model was tested for a wide range of volume concentration and temperature and shows wider applicability. [ABSTRACT FROM AUTHOR]

The paper gives a brief review of works describing bending torsion analysis of beams with corrugated web. The authors put forward a solution specifying V. Vlasov's famous thin-walled bars theory which is generally used to calculate stress-strain behaviour of beams with corrugated web bending torsion. The specification lies in the following: the researchers measure flexure-torsion characteristics of the cross-section while increasing pure torsion moment of the cross section by means of introducing equivalent flange thickness into calculations. To check the efficiency of the introduced method the authors calculated five beams with sinusoidal corrugation for two concentrated forces action. The paper introduces the results of these five methods of beam calculation including the one developed by the authors. The obtained results showed that the tension value in each case is almost the same (with maximum 7% difference in rates). The research also determines the scope limitations of the authors’ specified theory. [ABSTRACT FROM AUTHOR]

Ice slurry heat transfer characteristics in a straight horizontal tube were numerically studied in this paper. By using of CFD software, the VOF model in FLUENT 6.3, the simulation of ice slurry was performed to cover laminar and turbulent flow regimes with C is varying from 0% to 20%. The obtained results were firstly validated by the published experimental values. It is found that the discrepancy between the measured and calculated Nu is number is mainly in the range of ±15%. Then the model was applied to analyze the impact of initial conditions on ice slurry heat transfer. The present work shows that, ice slurry heat transfer performance are strongly dependent on the flow velocity and ice mass fraction, and heat flux density only has a small influence on the value of Nu is when ice slurry flows in turbulence. This paper aimed to use this model as a design tool to analyze ice slurry flow in different operating conditions. [ABSTRACT FROM AUTHOR]

In this paper, a mathematical model of connection method between ring-shaped heat-supply systems with multi-heat sources was established based on the requirement of limited-heating in accident conditions. The limited-heating coefficient, pressure bearing capacity of pipeline, heating capacity of heat source, operating parameters of circulating pumps were used as boundary conditions, and the minimum consumption of transmission energy of heat sources was considered to be the objective function. A case was analysed to illustrate the solving process and the calculation method of the model. Using the mathematical model proposed in this paper, the feasibility of the connection method between the heat-supply systems on accident conditions can be analyzed under steady state and system completely be controlled condition. The optimal connecting case was obtained. The results have important significance for urban planning and the reconstruction design of heat-supply system. [ABSTRACT FROM AUTHOR]

Sustainable development could have a significant impact on conventional construction, reducing or replacing steel and concrete as primary materials in structures. Bamboo, a natural resource, has been used as a general building material for decades in some regions of the world. Countries in Asia and South America have found many uses for bamboo because it grows rapidly and has excellent mechanical properties. The purpose of this paper is to test the designs of different configurations of bolted connections in order to create a composite bamboo I-shaped beam for further applications. Three different configurations of connections for a bamboo composite I-shaped beam were analyzed, with the purpose of identifying an optimal configuration that results in a stiffer, safer beam. A three-dimensional Finite Element Model (FEM) computational model was developed to identify areas of high stress concentration and maximum deflection for the various connection configurations. The findings of this paper are a first step in the process of considering and validating composite bamboo I-shaped beams as a primary construction material in structures such as bridges and buildings. [ABSTRACT FROM AUTHOR]

In modern ages, universities have shaped the civilized society and contributed to its knowledge base by educating the workforce, and providing consultation to government and businesses. In the wake of globalization, it is necessary to establish mutual beneficial relationships between universities and their urban areas; hence, the university - city complex model. In the context of Vietnam, most universities are located in urban areas; none of which, however, has fully engaged in the local community in meaningful ways. With the core idea of “Building an intelligent and ecologically friendly city”, this paper proposes the design of a university - city complex in Hung Yen province, Vietnam. This design will stimulate sustainable development of the local community through green architecture, spatial planning of university complex, and careful design of education programs and services. This paper will also present the conceptual knowledge of the subject, potential factors driving the development, and successful case studies of university - city complexes. [ABSTRACT FROM AUTHOR]

The paper deals with the basic requirements on structural properties combined with material properties for computational modeling of train brake shoes. It is a construction element consisting of base material made of graphitic cast iron and reinforcing steel insertion of simple geometric shape. The structural unit of a “brake shoe” must be functional during train wheels braking. Therefore, it is necessary to design a computational model allowing to simulate operation load and to predict future failure. Because of that, this paper focuses on structural properties with an impact on the construction unit material properties required for computational modeling. Manufacturing technology affects the quality of the final structure whose character may be the cause of the failure initiation. In the presented paper, authors aim to investigate in detail the structure and its imperfections lowering the required properties. These are the factors necessary to take into account in computational modeling of the simulated operating load of the given construction element. [ABSTRACT FROM AUTHOR]

This paper proposes a new modelling framework aimed at overcoming the current limitations of existing techniques for the representation of products and processes within a Technology Forecasting study. Starting from the review of the available modelling approaches, the authors define system requirements as the key elements to represent both drivers and barriers for the evolution of technical systems, analysed in the context of a business process. The new proposal allows such requirements to be mapped in an integrated and scalable model connecting finished goods with the related business processes, so as to collect the knowledge from different experts and stakeholders in a unified and manageable description, thus reducing the risks due to uncertain and partial representation. The paper presents also an example of application in the field of pharmaceutical tablet manufacturing, focusing on the industrial processes requiring the granulation of pharmaceutical powders. An in-depth discussion about the emerged criticalities supports the definition of further developments to make this approach more repeatable and suitable for Technology Forecasting methodologies. [ABSTRACT FROM AUTHOR]

This paper describes the first outcomes of a joined research project between Politecnico di Milano and Whirlpool Europe aimed at establishing a systematic industrial approach to anticipate technological demands and solutions to manufacture future household appliances, by taking into account emergence, performances and drawbacks of manufacturing technologies. This work adds new elements of analysis to the forecasting approach proposed by the authors in previous publications and updates its metric for classifying Evaluation Parameters with a detailed set of criteria to characterize the outcomes, the drawbacks and the main resources consumption of a generic industrial process. Such set allows a preliminary extraction of information from technical experts, with no specific TRIZ know- how, in order to ease the process of identifying the main barriers (in TRIZ terms, contradictions) limiting the development of current technologies and/or their substitution with new industrial processes. The original content of the paper is clarified by means of a case study related to an application of the methodology concerning the foaming process of domestic refrigerators. [ABSTRACT FROM AUTHOR]

This paper presents the first results of a Ph.D. program aimed at investigating the domain interface between TRIZ and Biomimetics within the scope of inventive design. Indeed, a few authors have already proposed as a relevant direction of research the identification of integration opportunities between TRIZ and Biomimetics towards a more effective and efficient inventive design methodology. The paper presents a comparison between the tools based on functional modeling used during the process of problem solving within TRIZ and Biomimetics. This comparison intends to elicit overlaps, complementarities and incongruences of these techniques. The indications about how to improve the process of describing natural solutions in an engineering way and how to describe technical problems in order to use natural information as source of inspiration are given by analyzing few examples. The results are discussed in terms of necessary modifications in the engineering problem description in order to use a database of biological functions (i.e. the Biomimicry Taxonomy) as a source of natural knowledge in the process of inventive design. [ABSTRACT FROM AUTHOR]

Among the open research issues in the field of inventive design, a careful attention should be dedicated to the definition of means to measure and improve the efficiency of educational and training processes as well as to assess the benefits of the introduction of TRIZ expertise into R&D and engineering teams. In fact, while TRIZ methods and tools have gained a certain acknowledgment as a means to improve problem solving and inventive design skills, a dominant model about its introduction in an industrial organization is still missing. The paper presents a study aimed at measuring the impact of TRIZ learning (tools and logic) with respect to individuals’ talent. The paper proposes an original methodology to investigate human approaches to inventive design tasks: definition of the test (Sample group and control group, Inventive problems); evaluation criteria (Aptitude to follow a logical problem analysis path; Aptitude to explore various perspectives of the problem; Aptitude to generalization; Overall correctness of the problem analysis task; Completeness of the analysis); comparison and correlation criteria (Pearson correlation). The proposed investigation methodology is clarified through the description of an exemplary application in design courses at Politecnico di Milano and at the Università di Firenze. [ABSTRACT FROM AUTHOR]

Precedence Diagram Method (PDM) has been the prevailing scheduling technique for decades. This popularity is due to its modeling flexibility over other techniques and the easy-to-understand mathematical model behind the technique. However, even this technique has its own limitations; modelling overlapped activities in a proper way seems to be a never-ending debate. The reason of this can be found in the fundamentals of PDM technique; the four precedence relationships, and the activities that are assumed to be continuous with constant production speed. These fundamentals of PDM have their own consequences to scheduling practice and it is more and more apparent among professional planners that activity overlapping cannot be modeled adequately. Different solutions were proposed for solving this problem from the application of negative lag, through the combination of SS and FF relations to activity fragmentation. All these solutions have their shortcomings. Probably the fragmentation technique has led to the development of point-to-point type of relation that can connect any arbitrary points of the dependent activities. The objective of this paper is to analyze the pros and cons of different solutions are in use for modeling overlapped activities. The main finding of the paper is that newly developed point-to-point relations are better from theoretical and practical point of view than the solutions based on traditional precedence relationships, but they still cannot provide theoretically perfect solution. [ABSTRACT FROM AUTHOR]

Recently developed point-to-point relations have greatly extended the modeling capability of the Precedence Diagram Method. These relations can connect any inner (and extreme) points of the related activities. Furthermore, the definition of multiple relations is allowed between the same two activities. These features make point-to-point relations suitable for modeling overlapping activities more easily and with greater precision than it was possible before. However, there is a lot of work ahead. Although both proper mathematical modeling, and the algorithm that handles both minimal and maximal relations are available, re-investigation of well-known definitions for float, critical path, critical path metrics, classification of critical activities etc. are still missing. This paper deals with the investigation of the critical path. It describes the ways in which an activity can be part of the critical path. Collecting the possible cases provides the opportunity for classifying critical activities. The main result of the paper is that it provides a method for determining the type of the critical activity based on the relationships going in and out of the activity. [ABSTRACT FROM AUTHOR]

4D modeling has been an applied research area for around two decades since the first seminal works in the nineties. In the last years, a number of case studies have been published both for demonstrating the various applications of 4D and for assessing technological propositions. However, in most papers only little place is given to the particular content of 4D models. In parallel, following the growing implementation of Building Information Modeling, 4D modeling process is usually recognized as a “BIM use”. In BIM implementations and protocols, the Level Of Development of datasets is a fundamental issue. This paper describes the application of two distinct “4D uses” conducted on a single pilot project. They aim to assess the levels of graphical and temporal details required for the implemented uses. The authors finally discuss the diversity of 4D uses with 4D models, both planned or ad-hoc, as well as the logical understanding related to 4D LOD. [ABSTRACT FROM AUTHOR]

This paper presents a simple membrane fouling model intended for use in conjunction with an activated sludge model to form an integrated model of a membrane bioreactor (MBR). It is based on an earlier development of Liang et al.[1] who divided fouling into short-term reversible fouling tantamount with cake deposition and long-term irreversible fouling representing th effects of irreversible particle deposition inside membrane pores. The original model was extended to account for cake detachment, back- flushing, and dependency of soluble microbial products (SMP) deposition on permeate flux. The model was identified on two sets of data from two experiments: a short-term flux stepping experiment under fluxes higher from the ‘threshold flux’ and a long-term filtration experiment under fluxes not exceeding the ‘threshold flux’. Additionally, the paper proposes a simple ‘pen and ruler’ identification method for unique estimation of model parameters based on the information obtained from flux stepping experiments. [ABSTRACT FROM AUTHOR]

This paper addresses the problem of locating leaks in water distribution networks. The approach presented here is based on steady-state modelling, supported by monitoring tank flow and pressure at strategic nodes. The selection of the pressure monitoring nodes is done applying graph theory concepts adapted to water distribution networks. Pressure monitoring data is then used to build an optimization problem: the objective function is the minimization of the differences between estimated and measured pressures at the monitoring points, the constraints are the common energy and mass conservation laws and the decision variables are the leak locations and flows. This optimization problem is solved by a simulated annealing algorithm presented in a previous work. The application of this approach in a set of case studies produced some encouraging results and this paper describes the complete procedure and draws some conclusions. [ABSTRACT FROM AUTHOR]

No one can deny the role of synthetic polymers as engineering materials - they are all around us in our everyday life. Also due to the constant progress in material engineering, polymers, and among them elastomers, find increasing usage in civil engineering. Computer modelling of elastomers requires special description of material and use of non-linear finite element method. Available, free and commercial software use many different approaches in elastomers modelling, thus comparison of results may display discrepancies. Even if used method is the same, its computer implementation may vary, therefore using various software, one can obtain differing output. The paper presents comparison of results obtained from four computational packages devoted to FEA: Abaqus, GetFEM++, Tochnog, FEBio. It can be seen as an overview of the software that can be used in modelling rubber-like components. It highlights differences in material description (for instance in names of hyperelastic laws and employed formulas) and used multi-field variational principles in modelling material's incompressibility. Examples included in the paper can be treated as benchmarks, that can be helpful in verifying third party software or the one developed by readers. [ABSTRACT FROM AUTHOR]

This paper describes simulation model of real network with various neutral earthing methods when a single pole earth fault occurs. Model was made using Matlab. The aim of the paper is to analyse values of the currents and of the temporary overvoltages with power frequency in case of a single pole earth fault. The currents of single phase to ground faults depend (along with the neutral earthing method) mostly on the earth capacitances of the overhead lines or cables connected to the network. A comparison of the network with a large number of long cables and network with mostly overhead lines was made with the purpose to determine their influence. With the intention to control results given by simulation models the mathematical model was created as well. The comparison of the simulation model results and calculated values show match. Simulation models are powerfull analysis tools used to validate different solutions of neutral point earthing. [ABSTRACT FROM AUTHOR]

Because of its good aerodynamic performance and excellent controllability, the PADS which using the parachute like a wing has been widely used. To reach the accurate delivery target, the flight dynamic performance of PADS is very important. It is the foundation of the aerial delivery system's controllability and stability analysis. In this paper, we analyse the PADS’ flight dynamic performance by simplifiedthe system at9-DOFand numerical modeling based on it. The system flight dynamic performance at the station of one side edge deflection and both side edge deflection have been compared. The results indicate that this paper's modeling and dynamic analysis way is viable. [ABSTRACT FROM AUTHOR]

Existing and widely used scheduling techniques suffer from many shortcomings and drawbacks. These are mainly due to the oversimplifications made in the late 50s, early 60s to adjust these scheduling models to the available mathematical and IT tools. In this paper, these shortcomings of network techniques are collected and classified. Following this, a new general model can be defined using a new representation system that allows, for example: • the use of loops for determining recurring activities, • precedence relations with arrows at both ends for modeling the sequencing problem in construction, • precedence relations that can be used to describe minimal and maximal spatial distances, • decision nodes with or without probability, etc. The third point of the above list is discussed in detail; an algorithm is presented in order to define the start of the succeeding activities, when the intensity of the activities change and both spatial and time distances can be defined. The algorithm is presented with the help of a practical example; generalization can easily be done based on this. Resources are assumed to be unlimited throughout the paper unless explicitly stated otherwise. The main result of this research is a more general scheduling model that better fits the needs of project planners than the existing methods. [ABSTRACT FROM AUTHOR]

Existing and widely used scheduling techniques suffer from many shortcomings and drawbacks. These are mainly due to the oversimplifications made in the late 50s, early 60s to adjust these scheduling models to the available mathematical and IT tools. In this paper, these shortcomings of network techniques are collected and classified. Following this, a new general model can be defined using a new representation system that allows, for example: • the use of loops for determining recurring activities, • precedence relations with arrows at both ends for modeling the sequencing problem in construction, • precedence relations that can be used to describe minimal and maximal spatial distances, • decision nodes with or without probability, etc. The third point of the above list is discussed in detail; an algorithm is presented in order to define the start of the succeeding activities, when the intensity of the activities change and both spatial and time distances can be defined. The algorithm is presented with the help of a practical example; generalization can easily be done based on this. Resources are assumed to be unlimited throughout the paper unless explicitly stated otherwise. The main result of this research is a more general scheduling model that better fits the needs of project planners than the existing methods. [ABSTRACT FROM AUTHOR]

Abstract: This paper focuses on modeling and calibration of a small and poorly documented (portion of the) water distribution network (WDN) that shows pressure problems. Field campaigns are conducted to reduce the inaccuracies found in the inventory's drawings and to aid building a first WDN model. A trial and error procedure was then used to produce successive refinements for the desirable WDN's model fit. The paper describes the path followed through the first model to the final calibrated model, including WDN's instrumentation, the definition of network zones and the measures taken to deal with the pressure problems. [Copyright &y& Elsevier]

Abstract: Today, more and more scientists agree with the hypothesis concerning the raising of the planetary ocean level due to global climate warming and consequently due to glaciers melting. Therefore, as a consequence of climate change phenomenon, the Black Sea level is raising as well, which led to the loss of significant areas of land due to marine erosion, but also the production of some cracks and penetration of salt water into the Razelm - Sinoe freshwater ecosystem in Romania. This paper uses a mathematical tool, which addresses the maintenance of the ecological balance of freshwater ecosystem, the transit of freshwater through the Razelm - Sinoe hydrotechnical complex, and from here into the Black Sea, required to ensure the hydraulic gradient from freshwater to saltwater. This would help maintaining vegetation as natural means for protection against the sea erosion, as well as to attenuate the coastal energy of waves, so as to ensure the shielding role together with the other coastal engineering construction. Besides, the strong reed vegetation represents a natural element of protection of levees already made or those in process of development, and also a retention element of fine particles brought by waves at times when sea level is high. The mathematical algorithm used in this paper take into account the principle of fluid flows in porous media. The vegetation of littoral from Razelm - Sinoe ecosystem was considered a porous media. The research results show the capacity of the vegetation to attenuate the waves’ energy in the study area. The mathematical model was especially conceived for a unique littoral area, which separates the Black Sea from Razelm - Sinoe ecosystem. The solution of protection exploits the natural environment; it is not expensive and falls into the natural-ecological aspect of the coastal zone. [Copyright &y& Elsevier]

Abstract: This paper presents some results of theoretical and experimental analysis of composite steel-concrete (SC) columns, which are completely or partially concrete-encased steel members. In practice, most composite SC columns are relatively slender. In design the second - order effects will usually need to be included. The main topic of the paper is a theoretical analysis of the second - order theory at composite (SC) columns. According to the results of the experiments, which were made in the Department of Concrete Structures and Bridges, Slovak Technical University of Technology in Bratislava (total of 18 columns were tested in two series), the effects of the second - order theory were analyzed. The experimental results were compared with theoretical from the model developed in the non-linear software Atena 3D. The evaluation of the results is also shown in comparison with the general design method according to Eurocode 4, Design of composite steel and concrete structures - Part 1.1: General rules and rules for buildings (EN 1994-1-1). [Copyright &y& Elsevier]

Abstract: The advances in robotics, in the last ten years, have enabled robot technology to solve many practical problems that humans encounter in day-to-day activities. But, even today manual scavenging of the sewage is practiced in urban areas of India, wherein man enter the manholes and clean the scales and clogs in the sewage pipelines manually with virtually no technical equipment. This practice might jeopardize the lives of humans; therefore, a sewage cleaning robot is essential to replace the human intervention. The conventional sewage cleaning robots available are not capable and effective in cleaning a variable diameter pipelines. In order to overcome this issue, an attempt has been is made to design and develop a reconfigurable type sewage cleaning mobile manipulator, which can efficiently clean the scales and clogs formed in the variable diameter sewage pipeline. A conceptual model of the manipulator has been created in solid model using solid works. It will give a clear understanding of the manipulator and its subsystem interactions. A prototype model of the manipulator has been developed based on the design concept and its working environment i. e, various goals that robot has to do after entering the sewage pipe and hence the functional requirements are finalized. It consists of various links and joints. The joints are drive through the various motors which are discussed in the paper. Preliminary investigations are carried out on the developed prototype model and some of the results are discussed in the paper. [Copyright &y& Elsevier]

Abstract: In this paper, we consider the stabilization and trajectory tracking of magnetic levitation system using PID controller whose controller gains are determined via Linear Quadratic Regulator (LQR) approach. Firstly, the nonlinear mathematical model of the system is obtained from the first principles. Then by applying Taylor's series, the non linear equation of motion is linearized around the equilibrium point to implement the stabilizing controller. Finally, the gains of the PID controller to achieve the desired response are determined using the LQR theory. Based on the natural frequency and damping ratio of the closed loop system, a new criterion for selecting the weighting matrices of LQR is proposed in this paper. Experiments are conducted on a Quanser magnetic levitation system to evaluate the performance of the proposed methodology and the experimental results prove that the proposed control strategy is effective not only in stabilizing the ball but also in rejecting the disturbance present in the system. [Copyright &y& Elsevier]

In this paper, a series of experiments was conducted by using a gas burner to characterize the flame geometry under the inclined surface condition and trench configuration. The inclination angle was systematically varied from 0° to 26°. The centerline temperature distribution of the inclined surface was measured and the flame geometry parameters were obtained by the post-processing of the side-view images. Results show that the flame tilt angle appears a linear decrease with the increase of the inclination angle for both the inclined surface and trench configuration experiments, and decreases faster for the trench configuration. The flame length shows a non-monotonic variation with the inclination angle and a transformation process of flame from the plume-type to attachment type is observed. There is no significant effect of the aspect ratio on the flame geometry parameters. The flame attachment length fluctuated with time was obtained. A variable-interval time-average (VITA) method was used to determine the level-crossing rate and the peak frequency location. The peak frequency location has a linear relationship with the horizontal flame length. The flame attachment length and the centerline temperature increase sharply from 15° to 20° under the inclined surface condition, indicating the occurrence of flame attachment. [ABSTRACT FROM AUTHOR]

Physical modelling has a long established history for the investigation of metal forming and other manufacturing processes. In recent times however its place and importance has diminished somewhat as a direct consequence of advances made in numerical modelling techniques. This paper re-examines the place of physical modelling and by means of selected examples demonstrates the benefits of the approach. Physical modelling often provides an indirect representation of the physics under consideration and may often involve scaling and the use of cheaper substitute materials. A question posed that has in some respects contributed to the diminution of physical modelling is whether the physical model is representative of the physics involved. Related to this question is a new approach to scaled experimentation that has appeared in the recent literature. The new approach is founded on the scaling of space itself and although the idea that space expands and distorts is not new to physics (e.g. cosmology and general relativity) its application to physical modelling is considered completely novel. The scaling concept enables the physics of processes to be projected into a scaled space and vice versa, thus providing quantification of the validity of any physical model. This aspect fortifies a particular weakness in the physical modelling approach making its reappraisal particularly timely. Selected numerical and experimental trials are being designed to showcase and reveal the benefits, validity and renewed importance of physical modelling. [ABSTRACT FROM AUTHOR]

Ductile fracture prediction is often considered as a challenging task in complex stress state applications, such as metal joining process. A systematic method for predicting the joint strength in the hot shear joining process is presented in this paper by considering two different ductile damage models, namely Johnson-Cook and modified Lemaitre damage models. Since the crack formation in metalworking is considered to be a combination of both load conditions and metallurgical properties, the microstructure evolution is taken into account by characterizing the considered material, AISI-1045, at different temperatures and for different strain rates and by testing different specimen shapes, namely round bar, joint bar, flat and notched specimens. The derived material properties have been inversely calibrated in order to be used in the developed numerical model. A shear joining process simulation has been implemented in DEFORM and have been validate with shear joining experiments carried out at 950°C, allowing to validate the accuracy of the proposed model in simulating the hot shear joining, both in terms of joining strength and identification of the damage locations. Thanks to a precise material characterization, and by utilizing the proposed numerical model, both the joining tool design and the process condition can be studied and improved. [ABSTRACT FROM AUTHOR]

In this paper, the new single crystal yield criterion developed by Cazacu et al. [1] is used to study the effect of the initial texture on the anisotropy in plastic properties of metal sheets. The directional dependence of the yield stresses and Lankford coefficients in uniaxial tension is calculated for polycrystalline sheets with textures described in terms of a Gaussian distribution of misorientations with scatter width increasing from zero (single crystal) to 45º. It is shown that the same fidelity in predictions is obtained for an ideal texture and for textures with misorientation scatter width up to 25º. Furthermore, irrespective of the number of grains in the sample, Lankford coefficients have finite values for all loading orientations. Therefore, using this new single crystal yield criterion for the description of the plastic behavior of the constituent grains, the polycrystalline behavior can be predicted with accuracy, and at a very low computational cost. Most importantly, once the single crystal behavior is known, no additional calibration or macroscopic mechanical tests are needed in order to predict the effect of different texture components on the polycrystalline behavior. [ABSTRACT FROM AUTHOR]

Micro forming is a promising technology with the trend towards miniaturisation in industry, and micro deep drawing (MMD) process is a fundamental micro forming method with potential applications in forming of cups, hollows and boxes and has great advantages comparing to other micro manufacturing methods. As the preferred material for electrical conductors, aluminium (Al)-copper (Cu) composite material processes advantages of the low density and cost of aluminium and good conductivity of copper. In this paper, MMD has been studied experimentally and numerically with a purpose of understanding the deformation behaviour of a two-layer Al-Cu composite in microscale. Al-Cu composite material was rolled to 50 µm in thickness and then annealed at 400 ºC. The drawability of the annealed composite was investigated by MDD experiments. FE models with Voronoi tessellations were established to simulate the Al-Cu composite material during MDD process. Considering the grain heterogeneity, each Voronoi tessellation has been assigned with different mechanical properties based on experimental data. The simulation results are in good agreement with the experiment ones. [ABSTRACT FROM AUTHOR]

The paper objective is to decrease a share of tool costs in the cost price of production manufactured at the expense of the composite and solid mills use control. In the course of research the authors used computer simulation with the finite elements. The studies proved that the composite cutters can compete with the monolithic cutters in terms of their efficiency while ensuring the required precision accuracy. Their cost is lower due to hard alloy savings. The outcomes of evaluation of the groove wall runout as a result of bending for cutters of different designs are given, and it is shown that the deviation is acceptable for engineering products. The effective application of both mills is shown. It is demonstrated that the smaller is the length of the required mill, the increasingly competitive composite mills become due to insignificant differences in their deformation compared to the deformation of the monolithic milling cutters and due to the considerable hard alloy saving. Thus, the greater length is required by the mill, the greater are the hard alloy saving, but also the greater is cutter deformation which reduces accuracy and processing performance. [ABSTRACT FROM AUTHOR]

This paper explores the process of positioning of the hydraulic drive with the original hydromechanical control subsystem. Using direct numerical simulation in Matlab Simulink software environment, the effect of parameters of the hydraulic control circuit is investigated: the control pressure and the conduction of hydro-mechanical valve-positioner on positional cycle accuracy and the speed of operation. The modeling is done taking into account the nonstationary processes in the flowing part of the control device, preset by experiment. The analysis and comparison of the dependencies obtained as the result of multifactorial computing and full-scale experiments confirm the adequacy of the developed mathematical model of the hydraulic drive and are necessary for further optimization of its control devices parameters. The research results allowed for the recommendations to be made that increase the efficiency of hydraulic control circuit for realization of the rational motion control position cycle of technical objects. [ABSTRACT FROM AUTHOR]