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Showing papers in "Applied Mechanics and Materials in 2014"


Journal ArticleDOI
TL;DR: The methodology and application of the very popular nonparametric test which is a rank based test named as Kruskal-Wallis is described, which is useful as a general non parametric test for comparing more than two independent samples.
Abstract: This paper describes the methodology and application of the very popular nonparametric test which is a rank based test named as Kruskal-Wallis. This test is useful as a general nonparametric test for comparing more than two independent samples. It can be used to test whether such samples come from the same distribution. This test is powerful alternative to the one-way analysis of variance. Nonparametric ANOVA has no assumption of normality of random error but the independence of random error is required. If the Kruskal-Wallis statistic is significant, the nonparametric multiple comparison tests are useful methods for further analysis. The statistical analysis of the application data in this paper was performed with software MATLAB.

267 citations


Journal ArticleDOI
TL;DR: In this article, the synergistic effect of combining multi-walled carbon nanotubes (MWNTs) and Fe2O3 nanoparticles on thermal conductivity of nanofluid was investigated.
Abstract: This study investigates the synergistic effect of combining multi-walled carbon nanotubes (MWNTs) and Fe2O3 nanoparticles on thermal conductivity of nanofluid. Results show that low percentage hybrid fillers loading improve thermal conductivity of water based nanofluid, due to the good dispersion and interfacial adhesion, which is confirmed by scanning electron microscope. Furthermore, the hybrid fillers provide synergistic effect on heat conductive networks. The thermal conductivity enhancement of water based nanofluid containing 0.05 wt % MWNTs and 0.02 wt % Fe2O3 nanoparticles is 27.75%, which is higher than that of nanofluid containing 0.2 wt % single MWNTs or Fe2O3 nanoparticles.

76 citations


Journal ArticleDOI
TL;DR: The SMA attributes that make them ideally suited as actuators in automotive applications are described and to address their limitations, feasibilities and prospects.
Abstract: Shape memory alloy (SMA) actuators have drawn much attention and interest due to their unique and superior properties, and are expected to be equipped in many modern vehicles at competitive market prices. The key advantage is that SMA actuators do not require bulky and complicated mechanical design to function, where the active element (e.g. SMA wire or spring) can be deformed by applying minimal external force and will retain to their previous form when subjected to certain stimuli such as thermomechanical or magnetic changes. This paper describes the SMA attributes that make them ideally suited as actuators in automotive applications and to address their limitations, feasibilities and prospects.

61 citations


Journal ArticleDOI
TL;DR: In this paper, the authors present the concept of operations, architecture and trajectory optimisation algorithms of a Next Generation Flight Management System (NG-FMS) for four dimensional (4D) intent-based operations (IBO) in the next generation Communications, Navigation, Surveillance and Air Traffic Management system (CNS+A) context.
Abstract: This paper presents the concept of operations, architecture and trajectory optimisation algorithms of a Next Generation Flight Management System (NG-FMS). The NG-FMS is developed for Four Dimensional (4D) Intent Based Operations (IBO) in the next generation Communications, Navigation, Surveillance and Air Traffic Management system (CNS+A) context. The NG-FMS, primarily responsible for the aircraft navigation and guidance task, acts as a key enabler for achieving higher level of operational efficiency and mitigating environmental impacts both in manned and unmanned aircraft applications. The NG-FMS is interoperable with the future ground based 4DT Planning, Negotiation and Validation (4-PNV) systems, enabling automated Trajectory/Intent Based Operations (TBO/IBO). After the NG-FMS architecture is presented, the key mathematical models describing the trajectory generation and optimisation modes are introduced. A detailed error analysis is performed and the uncertainties affecting the nominal trajectories are studied to obtain the total NG-FMS error budgets. These are compared with the Required Navigation Performance (RNP) values for the various operational flight tasks considered.

58 citations


Journal ArticleDOI
TL;DR: In this article, the authors identify machining difficulties of nickel-titanium based shape memory alloys and propose to change the cutting parameters such as feed rate, cutting speed and cutting depth.
Abstract: The purpose of this study is to identify machining difficulties of nickel-titanium based shape memory alloys. Nickel-titanium (Nitinol) is one the widely used shape memory material which is applied in many products in the aerospace, medical, and biomedical fields. NiTi alloy cannot be machined easily because of high tool wear, high cutting force, huge hardness and surface defects are made many problems into their machining. Investigation in micron precision shows plenty surface defects in machining process, something like debris of microchips, feed marks, tearing surface, deformed grains, material cracking and chip layer formation which consists the main problem in the machining of shape memory alloys. Moreover, these defects can be reduced or eliminated by changing the cutting parameters such as: feed rate, cutting speed and cutting depth so that, machining of nickel-titanium alloys would be improved.

58 citations


Journal ArticleDOI
TL;DR: In this article, an alternative technique of increase in oil recovery is offered by creating of a shock wave small intensity in the bottom fluid, with a high frequency of repeatability set of blows increases quantity of micro cracks in collector rock, increasing coefficient of permeability of layer without breaking its connectivity.
Abstract: In this research the alternative method is presented increases of oil recovery of an oil collector. Shock wave impact on layer. The technology is developed, advantage of this method is shown in comparison with layer hydraulic fracturing. For increase oil recovery and restoration of wells the traditional is widely applied technology of hydraulic fracturing of layer (flyuding), allowing on the short period to recover a well. Sense of a flyuding that hydrostatic pressure is created is considerable exceeding mountain and bringing to a rupture of a collector on one or several cracks. In this work the alternative technique of increase in oil recovery is offered by creation of a shock wave small intensity in the bottom fluid. With a high frequency of repeatability set of blows increases quantity of micro cracks in collector rock, increasing coefficient of permeability of layer without breaking its connectivity.

58 citations


Journal ArticleDOI
TL;DR: In this paper, a model of how to ensure power supply for a kindergarten of the city of Nish is presented on the basis of the calculations analysis, and the cases with regard to completed projects designed to use renewable energy sources in order to supply pre-school facilities with energy in other weather conditions are given.
Abstract: Pre-school facilities are considered to be specific buildings in the matter of construction and renovation. Space-planning features in design for pre-school facilities create special conditions for solar power use to ensure heat and power supply. The article deals with estimation of incoming solar power in reference to the surfaces oriented in different cardinal directions under the weather conditions of the city of Saint-Petersburg (Russia) and the city of Nish (Serbia). A model of how to ensure power supply for a kindergarten of the city of Nish is presented on the basis of the calculations analysis. The cases with regard to completed projects designed to use renewable energy sources in order to supply pre-school facilities with energy in other weather conditions are given herein.

54 citations


Journal ArticleDOI
TL;DR: The urban and architectural development of Cetinje from the XV century until World War II is described in this paper, where the authors describe the development of the city during this period depending on the development social forces, which led internal and foreign policy of the state.
Abstract: Built on the urban principles, Cetinje, as the royal capital of Montenegro untill 1914, for forty years of intensive develop ment and construction has achieved the urban functional content, which has made it closer to the developed European capitals. Its town-construction has been developing during this period depending on the development of social forces, which led internal and foreign policy of the state and sought that the stability and reputation of the state affect through the development and image of Cetinje, as its capital. This work includes urban and architectural development of Cetinje from XV century until World War II.

53 citations


Journal ArticleDOI
TL;DR: In this article, the authors deal with the methods and calculations made to obtain the data on solar radiation effects on sloping surfaces oriented in different cardinal directions in regard to Saint-Petersburg weather-related conditions.
Abstract: With the purpose to ensure extra solar power for buildings and improve quality of urban environment solar power has appeared to be sought-after in the majority of southern countries. In the case of the Northwest Region of Russia estimation of existing regional power reserves for construction sector is the fundamental factor when an issue of achieving possible ways to supply buildings with solar-based power is considered. The article deals with the methods and calculations made to obtain the data on solar radiation effects on sloping surfaces oriented in different cardinal directions in regard to Saint-Petersburg weather-related conditions. Electric power generation using solar photovoltaic modules (PV modules) has been defined under actual operating conditions.

52 citations


Journal ArticleDOI
TL;DR: In this paper, the authors present models and algorithms for real-time 4Dimensional Flight Trajectory (4DT) operations in next generation Communications, Navigation, Surveillance/Air Traffic Management (CNS/ATM) systems.
Abstract: This paper presents models and algorithms for real-time 4-Dimensional Flight Trajectory (4DT) operations in next generation Communications, Navigation, Surveillance/Air Traffic Management (CNS/ATM) systems. In particular, the models are employed for multi-objective optimisation of 4DT intents in ground-based 4DT Planning, Negotiation and Validation (4-PNV) systems and in airborne Next Generation Flight Management Systems (NG-FMS). The assumed timeframe convention for offline and online air traffic operations is introduced and discussed. The adopted formulation of the multi-objective 4DT optimisation problem includes a number of environmental objectives and operational constraints. In particular, the paper describes a real-time multi-objective optimisation algorithm and the generalised expression of the cost function adopted for penalties associated with specific airspace volumes, accounting for weather models, condensation trails models and noise models.

52 citations


Journal ArticleDOI
TL;DR: In this paper, a 3D dynamic explicit method for burnishing rolling process with taking into account surface after turning (as previous treatment) under ANSYS/LS-DYNA environment was established.
Abstract: In this study the process of burnishing rolling is considered as a geometrical and physical boundary and initial value problem, with unknown boundary conditions in the contact area. 3D dynamic explicit method for burnishing rolling process with taking into account surface after turning (as previous treatment) under ANSYS/LS-DYNA environment was established. The analysis covered surfaces characterized by vertical angles of the asperities in range: 60°÷150°. The simulation results (i.e. surface deformation, states of strain and stresses, depth of stress deposition) were evaluated. The influence of vertical angle of the asperities after turning process on the states of stress and strain and the depth of its deposition are presented.

Journal ArticleDOI
TL;DR: In this paper, a single-and multi-layered graphite growth phase is presented, and the results of a single and multi-layer graphene growth phase are used to optimize the industrial-scale production of low-cost poly crystalline graphene.
Abstract: The preparation of poly crystalline graphene from the liquid phase has been discussed.The mechanism of graphene growth from the liquid phaseon the Cu-Ni alloy and the type of atmosphere, used inthe graphene fabrication-acetylene, ethylene, hydrogen has been presented. Stages of nucleation and poly crystalline growth of graphene were identified. The paper presents theresults of a single-and multi-layered graphene growth phase.It is assumed the final result will mean the optimization of the industrial-scale production of low-cost poly crystalline graphene.

Journal ArticleDOI
Gang Lu1, Wenhua Zeng1
TL;DR: The paper synthetically introduces cloud computing techniques, including the currently non-uniform definition and the characteristics of cloud computing, and the core techniques of cloud Computing, such as data management techniques, data storage techniques, programming model and virtualization techniques.
Abstract: Conference Name:2014 International Conference on Sensors Instrument and Information Technology, ICSIIT 2014. Conference Address: Guangzhou, China. Time:January 18, 2014 - January 19, 2014.

Journal ArticleDOI
TL;DR: In this article, an estimation method assigned to define impact of partial shadowing on the surfaces of photovoltaic modules with respect to an amount of electric power a solar power system generates is presented.
Abstract: Use of renewable energy sources is an integral part of the concept developed for improving energy efficiency of buildings. This study is dedicated to the problem of solar power supply for the buildings under the conditions of high-density urban development. The article deals with an estimation method assigned to define impact of partial shadowing on the surfaces of photovoltaic modules with respect to an amount of electric power a solar power system generates.

Journal ArticleDOI
TL;DR: In this article, an incremental modeling and numerical solution of the contact problem between movable elastic or rigid tools and elastic/visco-plastic bodies developed in [ is adopted to the numerical simulation of thread rolling process for the case of rigid tool (threading head) and elastic or viscoplastic body (pipe or bar).
Abstract: This work describes the thread rolling as a real object and its physical and mathematical modelling. An incremental modelling and numerical solution of the contact problem between movable elastic or rigid tool and elastic/visco-plastic bodies developed in [ is adopted to the numerical simulation of thread rolling process for the case of rigid tool (threading head) and elastic/visco-plastic body (pipe or bar). An update Lagrangian formulation was used to describe nonlinear phenomena on a typical incremental step. For solution of discrete equations of motions and deformations of the object the explicit integration method was applied. The algorithm and application of 3D numerical analysis in ANSYS program were elaborated. This algorithm let for determination of influence of friction coefficient, initial yield stress and plastic hardening modulus. This factors influence will be carried out with 5 levels rotary experiment plan, which let for elaboration of regression equation to describe this relationship. Exemplary results of 3D numerical analysis of displacement and strain in thread for different conditions of rolling process are presented.

Journal ArticleDOI
TL;DR: Mobile robot vision system based on image information on environment is constructed which combined by the frame difference method and background subtraction for target detection and the main idea of three frame difference image method is combined to complement each other to overcome each other's weaknesses and improve the effect of target detection.
Abstract: Mobile robot vision system based on image information on environment, to make it automatic separation from obstacles and achieve precise mathematical description of obstacles, we construct detection model which combined by the frame difference method and background subtraction for target detection, comprehensive utilization of the main idea of three frame difference image method, the background subtraction and frame difference method combined to complement each other, thereby overcoming each other's weaknesses and improving the effect of target detection, experiment results show that this method can effectively improve the efficiency of target detection.

Journal ArticleDOI
TL;DR: In this paper, the authors present the key development measures for boosting economic growth in Montenegro in the future with a focus on the main goals of the construction and housing sector and proposed measures for their implementation.
Abstract: This paper presents the key development measures for boosting economic growth in Montenegro in the future with a focus on the main goals of the construction and housing sector and proposed measures for their implementation - in order to improve the competitiveness of the construction sector.

Journal ArticleDOI
TL;DR: In this article, reinforced soil beds are used as an efficient method to build artificial foundations based on weak soils, where the dimensions of compacted beds quite often appear to be overestimated, and this results in increase in costs and working hours needed to construct artificial foundations.
Abstract: Changing a layer of weak soil in deformed foundation with a compacted soil bed consisted of various strong materials (sand, gravel, pebble-gravel, production waste materials). Existing calculation methods and techniques to build compacted soil beds based on weak highly compressive soils do not meet up-to-date requirements. Calculation methods used the dimensions of compacted beds quite often appear to be overestimated, and this results in increase in costs and working hours needed to build artificial foundation. The paper presents the possibility of using reinforced soil beds as an efficient method to build artificial foundation based on weak soils.

Journal ArticleDOI
TL;DR: From the development of BIM, it can be concluded that BIM is a new methodology that involves the use of technologies in order to improve collaboration and communication of construction players as well as the management of documentation.
Abstract: Conventional practice on managing information in construction has sometimes created a miscommunication and errors among construction players. Therefore, Information Communication Technology (ICT) has introduced Building Information Modeling (BIM) for managing construction projects effectively and efficiently. Different terms on definition of BIM have been used and expanded widely with different perspectives. The aim of this paper is to explore the notion of BIM development from the year of 1975 to 2013. The methodology of this paper is based on literature review on BIM definitions. The findings reveal that there are six perspectives in BIM development which are design, estimation, construction process, building life cycle, performance and technology. From the development of BIM, it can be concluded that BIM is a new methodology that involves the use of technologies in order to improve collaboration and communication of construction players as well as the management of documentation.

Journal ArticleDOI
TL;DR: In this article, the authors used the concept of the artificial neural networks and the results of the performed numerical analyses as input parameters, the prediction model for defining the fire resistance of RC columns incorporated in walls and exposed to standard fire from one side, has been made.
Abstract: Using the concept of the artificial neural networks and the results of the performed numerical analyses as input parameters, the prediction model for defining the fire resistance of RC columns incorporated in walls and exposed to standard fire from one side, has been made. A short description of the numerical analyses of columns exposed to standard fire ISO 834, conducted by the computer software FIRE are presented in this paper. The software is capable of predicting the nonlinear response of reinforced concrete elements and plane frame structures subjected to fire loading, carrying out the nonlinear transient heat flow analysis and nonlinear stress-strain response associated with fire.

Journal ArticleDOI
TL;DR: In this paper, the authors discuss one of the ranking criteria QS - the proportion of foreign students - on the basis of activities of the Program "5-100-2020" and activities Civil Engineering Institute of Polytechnical University on attracting foreign students.
Abstract: St. Petersburg State Polytechnical University - Russian and world leader in higher engineering education. In 2010 he received the status of a national research university. In 2013, the Polytechnical University among the 15 universities of Russia, who won the competitive selection for the right to obtain a grant of the Ministry of Education and Science of Russia in order to increase their competitiveness among the world's leading research and education centers. Thanks to the activities of the Program “5-100-2020” St. Petersburg State Polytechnical University in 2020 should enter the top 100 QS World University Rankings.The article discusses one of the ranking criteria QS - the proportion of foreign students - on the basis of activities of the Program “5-100-2020” and activities Civil Engineering Institute of Polytechnical University on attracting foreign students. Considered activities such as increasing the number of international educational programs in English, participation Civil Engineering Institute in international educational exhibitions, partnerships with universities and abroad, primarily belonging to the rating of universities QS 500.

Journal ArticleDOI
TL;DR: In this paper, the capacity of rear ventilated facades is defined and theoretical dependences of the main characteristics of the flow, helping to pick up an optimum design in thermogravitational convection conditions are offered.
Abstract: In this article the capacity of systems of rear ventilated facades is defined In work theoretical dependences of the main characteristics of the flow, helping to pick up an optimum design in thermogravitational convection conditions are offered

Journal ArticleDOI
TL;DR: In this article, the authors focused on the identification and prioritization the factors challenging the implementation of BIM in Malaysian construction industry and the prioritization of such factors is expected to help the major stake holders to address the issues according to their priority which will save lot of previous time and financial with smooth implementation of bIM in Architecture, Engineering and Construction (AEC) industry in future project.
Abstract: The construction industry of Malaysia is very dynamic in nature and the adoption of new technological advancements and construction methods has been a prime concerns for its key players and stakeholders. However, the adoption of BIM in such a dynamic industry is observed to be limited and its implementation has not been as successful as it should have been. The study focuses on the identification and prioritization the factors challenging the implementation of BIM in Malaysian construction industry. The data has been administrated through designed questionnaire by identifying the factors / barriers, by literature review, for implementation of BIM in construction industry. The prioritization of such factors is expected to help the major stake holders to address the issues according to their priority which will save lot of previous time and financial with smooth implementation of BIM in Architecture, Engineering and Construction (AEC) industry in future project.

Journal ArticleDOI
TL;DR: The overall aim is to create a comfortable and highly effective interface suitable both for exploration and manipulation tasks in mobile robotics, with main focus on visualization of stereoscopic images from robot cameras.
Abstract: This paper mentions some problems related to utilization of a head-mounted display (HMD) for remote control of mobile robots by a human operator and also presents a possible solution. Considered is specifically the new HMD device called Oculus Rift, which is a very interesting device because of its great parameters and low price. The device is described in the beginning, together with some of the specific principles of the Oculus 3D display. Then follows the design of a new graphical user interface for teleoperation, with main focus on visualization of stereoscopic images from robot cameras. Demonstrated is also a way how to display additional data and information to the operator. The overall aim is to create a comfortable and highly effective interface suitable both for exploration and manipulation tasks in mobile robotics.

Journal ArticleDOI
TL;DR: In this article, the relevance and options for education in the field of security in the construction are discussed and a useful experience of foreign construction companies and training centers in construction safety area.
Abstract: Construction refers to a number of industrial processes with increased risk. Every year on the construction objects there are many accidents. Big amount of accidents have some reasons, including the organizational and related to the lack of knowledge in the field of safety. The article discusses the relevance and options for education in the field of security in the construction. Would be particularly useful experience of foreign construction companies and training centers in construction safety area.

Journal ArticleDOI
TL;DR: In this article, the first development cycle of a numerical method creating is considered, creating of the stiffness matrixes of thin-walled finite elements of various types using the semisheared theory (by V.I.Slivker).
Abstract: Recent years there have been observed a wide application of a metalware in industrial and civil engineering. Special place in the building industry is belonged to light steel thin-walled constructions having a lot of technological advantages. In the article the first development cycle of a numerical method creating is considered – creating of the stiffness matrixes of thin-walled finite elements of various types using the semisheared theory (by V.I.Slivker) – depending on a way of approximation of functions of deformations (torsion and warping): 1. Linear approximation of torsional functions with a 2-central finite element having 4 transitions; 2. Quadratic approximation of torsional functions and linear approximation of warping function with a 3-central finite element having 5 transitions; 3. Cubical approximation of functions of torsional and warping functions with a 3-central finite element having 6 transitions. Thus deformation functions (torsional angle and warping) are approximated as mutually independent functions.

Journal ArticleDOI
TL;DR: In this paper, a 3D finite element analysis of the ductile fracture, strain distribution and stress in blanking process with the assumption geometrical and physical nonlinearities is presented.
Abstract: The shearing process such as the blanking of sheet metals has been used often to prepare workpieces for subsequent forming operations. The use of FEM simulation is increasing for investigation and optimizing the blanking process. In the current literature a blanking FEM simulations for the limited capability and large computational cost of the three dimensional (3D) analysis has been largely limited to two dimensional (2D) plane axis-symmetry problems. However, a significant progress in modelling which takes into account the influence of real material (e.g. microstructure of the material), physical and technological conditions can be obtained by using 3D numerical analysis methods in this area. The objective of this paper is to present 3D finite element analysis of the ductile fracture, strain distribution and stress in blanking process with the assumption geometrical and physical nonlinearities. The physical, mathematical and computer model of the process are elaborated. Dynamic effects, mechanical coupling, constitutive damage law and contact friction are taken into account. The application in ANSYS/LS-DYNA program is elaborated. The effect of the main process parameter a blanking clearance on the deformation of 1018 steel and quality of the blanks sheared edge is analyzed. The results of computer simulations can be used to forecasting quality of the final parts optimization.

Journal ArticleDOI
TL;DR: Local damage detection in bearing/gearboxes is one of the most intensively explored problems in condition monitoring literature as mentioned in this paper, however, specific factors related to the mining industry, require adaptation of existing methods or even developing new approaches.
Abstract: Local damage detection in bearings/gearboxes is one of the most intensively explored problems in condition monitoring literature. Also for mechanical systems used in mining industry this issue might be critical due to short time local overloading of surfaces in contact in gear-pair or bearings that often happens during operation. In general, the problem of local damage detection is well defined in literature, however, specific factors related to the mining industry, require adaptation of existing methods or even developing new approaches. In the paper, some of the most promising techniques with mining machinery context are briefly re-called. The key problems identified for mining machines are: operation under time-varying load/speed conditions, presence of time varying signal to noise ratio and non-Gaussian noise (impulses that appear incidentally, randomly, not with expected cycle or cyclically, however with different cycle related to another damage). All these situations motivated us to find novel solution. The paper might be considered as brief review of recent achievements in the field rather that comprehensive, holistic description of the problem.

Journal ArticleDOI
TL;DR: The main focus is made on collaborative model development, including model decomposition issues and implementation of generic frameworks for polyvariant model use, as well as ideas for improvement of modeling infrastructure suitable to perform multi-factor computer experiments with existing crop simulation models.
Abstract: Some problems of decision support systems in computer aided agriculture are discussed. The main focus is made on collaborative model development, including model decomposition issues and implementation of generic frameworks for polyvariant model use. A current state and prospective ideas for improvement of modeling infrastructure suitable to perform multi-factor computer experiments with existing crop simulation models are presented.

Journal ArticleDOI
TL;DR: In this paper, a new method for machining low-rigidity shafts is developed to control the elastic-deformable state of these shafts in a technological system and to produce parts with the required accuracy during turning.
Abstract: The study determines the most suitable pattern of alignment and fixing of low-rigidity shafts; it also presents factors that determine such choice. The part is fixed both by force closing and kinematic closing. A new method for machining low rigidity shafts is developed to control the elastic-deformable state of these shafts in a technological system and to produce parts with the required accuracy during turning. To implement this new developed method for low rigidity shafts, an apparatus is designed. The apparatus allows to increase the rigidity of shafts during machining by the application of axial tensile force to the workpiece. Rational prime costs of preparing technological alignment centers at the stage of production preparation are determined; knowing these costs, it is possible to select a suitable machining technology for low rigidity shafts, to produce a technology-oriented design, and to reduce the costs of machining these shafts.