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This paper deals with trajectory tracking control of a quadcopter in a horizontal plane. A full rigid body model of the flying vehicle that doesn’t assume smallness of the Euler angles is considered. For synthesis of the tracking control the nonlinear dynamics inversion approach is used. Three different control strategies with restrictions on the orientation of the quadrotor are studied.

An Autonomous Surface Vehicle (ASV) is a vehicle in the form of a ship on the surface of the water that can move without a crew on it or operate automatically. This study used the Touristant ASV with a length of 4 meters, a diameter of 1.5 meters, and a height of 1.3 meters. The contribution of this paper is the estimation of ASV position and ASV motion influenced by wind speed and wave height. The estimation method used is the Ensemble Kalman Filter (EnKF) method. EnkF is applied to the nonlinear ASV model to obtain a small position error. In our simulations, we conducted 3 scenarios based on the number of generated ensembles, that are 100, 200 and 300 ensembles. The position error generated from the simulation showed that the simulation with the lower position error has an accuracy more than 95%. The position error of x is 0.009 meters, the position error of y is 0.008 meters, and the position error of XY plane is 0.01 meters.

Increasing efficiency in raw material and energy usage is vital, even more in sectors, such as the hot forging industry, where material accounts for 50% of component price and energy costs are continuously rising. One of the methods to achieve this is to minimize material waste. Traditionally, high-quality gears for the automotive sector are machined to shape from forged preforms which is wasteful of both materials and energy. Attention has now turned to the forging of tooth gears by conventional forging. However, this could require high forging loads and therefore huge press sizes. Some gears may also be difficult to form due to the placement of their teeth. Forging of tooth gears is thus not a straightforward task. In this context, rotary forging is a powerful alternative. It uses incremental deformation locally with the material to achieve near net shape results, minimizing machining. Due to the reduction in contact, it also allows the forging load to be decreased substantially, resulting in smaller presses. This paper shows the development of the rotary forging process in combination with conventional forging to obtain crown gear teeth as a demonstration case. First, the hot conventional forging is shown, based on obtaining the rotary preform by a closed die forging operation. Then rotary forging is defined as a semi-finished operation to achieve the forged teeth. The objective is to reduce the initial billet weight, checking that folds and filling defects do not appear. A thermomechanical chained model has been developed based on FEM and experimental tests carried out in a pre-industrial environment. The prototypes result in increased yield from raw material (around 15% saving compared to machining) and they can be manufactured with less than 50% of the load required by conventional forging processes. Quality and metallographic requirements are also fulfilled. This work was supported by the Basque Government under the CORONAT project (Hazitek program: IG2015/00331, ZL-2016/00070, ZL-2017/00109). The authors wish to thank FORGE ® NxT for their assistance on simulation methodology and INDUSTRIAS PUIGJANER S.A for use of the forging tool system developed.

In this paper, we discuss a mathematical model of changes in smoking behavior, in which the population is classified into five classes as follow: potential smokers, light smokers, heavy smokers, smokers who temporarily quit smoking and smokers who permanently quit smoking. In this model, the crude death rate of each classes are set apart. The density-dependent death rates are also considered in this model. From this model, we find the smoking-free equilibrium point and analyze the stability by using reproduction number. Then, we analyze the sensitivity of reproduction numbers to determine the parameters that influence the dissemination of changes in smoking behavior. After that, we perform numerical simulations to illustrate the analytic conclusions and to know how far the influence of some parameters on the dissemination of changes in smoking behavior so that we can predict the ways to overcome the dissemination of smoking behavior.

Large-scale floating vertical axis wind turbines have great potential for offshore applications. This paper will review the recent developments for generating torque and controlling vertical-axis wind turbines (VAWTs) specifically for floating applications. The phenomena presented include dynamic stall and pitching of the blades, as well as design of airfoils for VAWT applications.

The selection of the appropriate learning model is very important because it can make more meaning in the process of teaching and learning activities. Teacher Professional Education Program expects the practitioner to be able to choose appropriate learning model to the class conditions. Even in schools that have implemented a zoning system, namely public junior high school 5 Surakarta. This paper aims to find out the description and comparison of the four learning models used by Teacher Professional Education Program at public junior high school 5 Surakarta towards understanding students’ mathematical concepts. The learning model used in the research were Number Head Together (NHT), Discovery Learning (DL) with recitation, Problem Based Learning (PBL) and Teams games Together (TGT). The methodology of this research uses descriptive and inferential statistics. Thus, inferential statistical analysis using one-way variance analysis. Data are understanding students’ mathematical concepts were obtained by the tests. From the results of the study, it can be found that the average understanding of mathematical concepts of students using DLwith recitation has a better effect on understanding students’ mathematical concept. In contrast, TGTs’ class produce the lowest understanding students’ mathematical concepts while the most varied understanding students’ mathematical concepts are in the NHTs’ class.

This paper presents the way of serialization RDF representation of Knowledge patterns by RDF/JSON syntax. Knowledge patterns are general patterns of knowledge which can be used many times. The use of pattern is realized by morphism, the process when symbols from a pattern are renamed by concrete symbols. RDF/JSON is a concrete syntax for RDF which is defined in the RDF Concepts and Abstract Syntax W3C Recommendation and uses JavaScript Object Notation (JSON).

Vibration Assisted Machining is an example of sustainable manufacturing concept application and as an alternative machining process, to improve machine performance and machined surface quality. Machine construction and system respond toward the applied active vibration, actuator selection with a function to generate vibration, the direction, and placement of vibration on to the machine, workpiece properties, and product complexity of the required product, are the main aspects to design Vibration Assisted Machining for machining process especially in microscale. VAM design had been introduced and investigated by many researchers for many types of machine and manufacturing process, thru the structural static and dynamic load on to machine structure due to the vibration additional at its resonant frequency toward the machined surface quality, by conducted simulation or experimental or comparison of both. Nevertheless, the research about VAM design development for the miniaturized machine for milling was still limited. Thus this paper would like to introduce VAM mechanism in which the workpiece would be positioned and customized for miniaturized milling machine, by implementing product development evaluation and finite element method to obtain the stress and displacement plot. Piezoelectric actuator and flexure combination was chosen as the most compatible design in comparison to the application of mechanical and vibration motor system. Finite element simulation showed VAM able to uphold the targeted machining forces and to vibrate workpiece with displacement within several micrometers.

The concept of a smart home has developed since the 90s. Where the initial goal of the emergence of the concept of a smart home is to create home automation that can increase the comfort of its residents. Smart home technology enables communication between household appliances and users and improves automation, monitoring and remote-control capabilities. Various studies have been conducted to develop smart home technology. The main purpose of developing a smart home is to meet human needs, namely, to increase user comfort and make everyday life easier. In its development, there are several aspects in a smart home that must be met, namely Security and Safety, Energy Management, and Comfort Control. In various countries have started implementing smart home simulators as learning media, various studies also show that the use of simulators can help in understanding a technology. But until now, in Indonesia, there is still no simulator/trainer who can facilitate learning about smart home technology. Therefore it is necessary to develop intelligent home prototypes that are integrated into one product to facilitate this learning. In this case, context-aware technology is a solution that can be used in the development of a smart green building. Technology context-aware is a term for a smart home that has the intelligence to automate home devices based on the context of the occupants. This paper aims to be a reference in developing smart home prototypes that fulfil the smart home aspects so that they can facilitate learning about smart home technology. This article was prepared by applying the method of critical analysis of literature published from 1992 to 2019 in journals and proceedings in Indonesian and English. As a follow up to future research, this article proposes the development of context-aware smart home simulator to facilitate learning about smart home technology.

In this paper, an experimental campaign is described. The high purity Nickel sheet with a thickness of 500 microns is tested at low triaxiality. Thanks to a novel geometry, the axial tensile force is converted to shear the material in a local region. Different series of tests are carried out in function of grain sizes. A strong influence on the global mechanical response can be observed due to different numbers of grains through the thickness of sample. The experimental curves are reproduced by finite element simulations with an isotropic macroscopic Hollomon constitutive law relying on different sets of parameters. Next, a small representative volume is considered. Using the identified parameters for each grain size, a sandwich approach is applied. The results of the single constitutive law approach and the sandwich approach are compared.

Numerical methods are an important requirement for the evaluation and analysis of sheet metal forming processes. In order that quality and development of the final component can be reproduced, it is important a higher accuracy of the obtained numerical results, which in turn needs the most correct material behavior characterization. This paper presents a study of the earing height profile, wall thickness distribution and punch force evolution for dual-phase steel sheets, using a deep drawing cylindrical cup test. Finite element simulations and experimental tests have been performed in order to evaluate and compare the obtained results for this kind of advanced high strength steels. The numerical simulation of the cylindrical cup test was carried out using a user subroutine in the FE code with different implemented anisotropic yield criteria, namely Hill48, Barlat 91 and CPB06. Concerning results for earing height profile and wall thickness distribution it is observed that Hill48 and CPB06 give similar predictions and close to experimental points. On the other hand, the predicted punch force evolution is not very sensitive to the selected yield criteria and their results are very closer to experimental data.

The aim of this paper is to provide evidence concerning the validity of the purchasing power parity (PPP) in the euro area. By applying unit root tests we find evidence of the PPP for the panel of the 12 euro area countries over the period 1970 – 2017, more concretely for the real exchange rates of Austria, the Belgium-Luxembourg Union and Ireland.

Improved stability of the node-to-node (NTN) algorithm gained by modification of the algorithm with regard to the explicit method is presented in this paper in order to enable fast and precise analysis of models containing NTN contacts in structural dynamics using Finite Element Method. The key issue is to fulfil contact conditions and prevent solution instability. The instability can be observed if the time step exceeds the critical time step, which is directly derived from the element stiffness and tends towards zero as connected nodes get closer to each other [1]. This is the main problem of NTN contacts in the explicit method.

The C++ Standard Template Library (STL) is the most well-known and widely used library that is based on the generic programming paradigm. STL takes advantage of C++ templates, so it is an extensible, effective and flexible system. Professional C++ programs cannot miss the usage of the STL because it increases quality, maintainability, understandability and efficacy of the code.However, the usage of C++ STL does not guarantee perfect, error-free code. Contrarily, incorrect application of the library may introduce new types of problems. Unfortunately, there is still a large number of properties that are tested neither at compilation- time nor at run-time. It is not surprising that in implementations of C++ programs so many STL-related bugs may occur.It is clearly seen that the compilation validation is not enough to exclude STL-related bugs. For instance, the mathematical properties of user-defined sorting parameters are not validated at compilation phase nor at run-time. Contravention of the strict weak ordering property results in weird behavior that is hard to debug. In this paper, we argue for a static analysis tool which finds erroneous implementation of functors regarding the mathematical properties. The primary goal is to support Continuous Integration pipelines, using this tool during development to overcome debugging efforts.

High Temperature Gas Cooled Reactors (HTGR) have many advantages such as inherent safety feature and high efficiency. National Nuclear Agency of Indonesia (BATAN) is developing a small size HTGR which called Experimental Power Reactor (RDE) to generate 10 MW thermal power. On the RDE design development, it is expected that a number of fuel elements are circulated pneumatically in to the reactor core by the fuel handling system every day. The fuel elements are transported vertically in a pneumatic pipe, with length 23 meters. Stability and reliability of the pneumatic transportation play important key factors in the fuel element transportation. In this paper, a theoretical approach to determine the operating pressure and velocity related to the compressed gas carrier in the pneumatic transportation is proposed. The analysis is made by considering several forces acting on the fuel element., such as drag force and force due to fuel mass. Analysis of carrier gas velocity and pressure is made under several stages: during the equilibrium stage and during the lifting stage. This research may provide an important basis in providing the operating parameters in the development of RDE. The principle of drag force and Bernoulli equation were used to determine the operating pressure and velocity to be applied in the development of experimental power reactor. From the calculation, it was obtained that in order to transport a fuel pebbel from the starting pneumatic system, which located in the lower part of pneumatic system, to the outlet pipe of pneumatic system facing the reactor, which located 23 meters above the former location, the velocity required was 1,063.95 m/s. The required pressure to produce such velocity was 39.25 Bar. Since the Fuel Handling System (FHS) equipments were operating at 30 Bar, then the penumatic system would be operating at 9.25 Bar.

In this paper, a relationship between the “money supply”, “average monthly wage”, “population accumulations” and volume of retail trade (“consumption”) is studied. A statistical econometric model is constructed. To understand the evolution of the model, the dynamic approach is used, with the help of which 36 variants of the model are constructed, which give an understanding of the changes in the influence of the regulators on “consumption”. The study is based on the data obtained from a Russian source in 2004-2016. The main results are: 1) the difference between influence of the indicators “money supply” and “average monthly wages” on consumption is revealed; 2) the character of links of the studied regulators with economic crises is established; 3) the nature of the relationship between “population accumulations” and “consumption” is defined.

The drilling of dissimilar materials in hybrid structures is one of the main machining operations in the aeronautical field. In order to reduce cycle-time, the aerospace industry is searching for the implementation of One-Shot (OS) strategies to drill CFRP/Ti6Al4V hybrid stacks with double-pointed angle cutting-tools, due to its good behavior when CFRP is drilled. However, there is a lack of information about its behavior when CFRP/Ti are drilled. For this reason, in this paper a study of the influence of the double tip geometry on the final quality of the bores has been carried out. Macro (diameter, burrs and delamination) and micro-geometric features (surface roughness) have been evaluated, and their deviations have been directly related with the main wear mechanism present in the process, adhesion and abrasion. Increasing in diameter can be related with the adhesion of Ti, while increase in delamination and burr heights are associated with a severe loss of cutting capacity due to abrasive wear. As was expected, double tip angle is not the best choice for drilling Ti alloys due to quick generation of burrs. In the opposite way, it offers good results in the machining of CFRP.

Bimatrices are an influential and an advanced tool which can be manipulate over one linear model at a time. In this paper, we introduce the concepts of conjugate secondary k-normal centro-hermitian bimatrix and also discuss some of its properties. We obtain the sum and the product of centro-hermitian matrix with the normal bimatrix. We interpret the concepts of s-symmetric, k-symmetric and s-k-symmetric for the centro-hermitian bimatrices. We provide the relationship between the interchange matrix (VB) and permutation matrix (KB).

In this paper, numerical analysis of laminar mixed convection of an isothermally heated vertical channel has been carried out using finite element method. Both of the side walls of the vertical channel are maintained at constant high temperature, whereas the inlet air follows Poiseuille’s velocity profile at cold temperature. To solve this problem, two dimensional Navier-Stokes and energy equations are considered as the governing equations. The variation of flow characteristics are obtained from fixed Grashof number (Gr = 100; Re = 10, 100, 500), fixed Reynolds number (Re = 100; Ri = 0.1, 1, 10) and fixed Richardson number (Ri = 1; Re = 10, 100, 500). The results are presented in terms of isotherms, streamlines, temperatures and velocity profiles across the channel. The results showed that the average Nusselt number on the hot walls increases with the increment of Re at constant Gr. Similar enhancement of heat transfer is observed with the decrement of Ri while Re is kept constant.

In this paper the problem of mutual interaction of incompressible viscous fluid flow with an elastic structure is considered. A model problem of aiflow induced vibratioon of a simplified human vocal folds model is studied. The main attention is paid to the problem of the periodical collisions of vocal folds. First, these collisions are taken into account in the flow model by the application of a suitable inlet boundary condition. Further, in the structure model the contact is resolved with the aid of application of Hertz forces. Numerical results are shown.

Isentropic flows of a one-dimensional gas dynamics equations in Lagrangian coordinates are studied in the paper. Equations describing these flows are reduced to the Euler-Lagrange equation. Using group classification and Noether’s theorem, con-servation laws are obtained. Their analogs in Eulerian coordinates are given.

Timisoara, the city with most numerous number of historical building from Romania has won the competition for European Cultural Capital in 2021. In this sense there is a complex and important program of rehabilitation of those buildings and also a large program of integrating the historical and geospatial information in webGIS platforms. This fact is in accordance with the European Commission recommendation regarding i2020 an informatics society. The aim of this paper is to present a model of creating 3D objects using laser scan technology (LiDAR) that is one of the most important techniques used to acquire spatial data. It scans quickly the architecture point by point; registers and joints point cloud to digitally simulate the object’s shape; finally, it reconstructs the 3D model accurately. It also produces construction drawing including ichnography, elevation, and cutaway. In addition, detailed structure and vignette can be acquired by close-range photogrammetry method, which produces orthoimages and linear drawings. This method is especially fit for surveying historical architecture that lacks construction records.

Let S ⊆ V(G). Then S is said to resolve the whole graph G if every vertex in V(G) is uniquely determined by its distance-vector to all vertices in the set S. The minimum cardinality of a resolving set is called as the metric dimension of G and is denoted as β(G). This paper aims to determine the metric dimension of a few families of graphs.

Boiler is one of power plant equipment that has function to produce steam. Thermal boiler efficiency is defined as the ratio of energy output to energy input to produce steam. There are two methods for evaluating boiler efficiency, namely direct method (input output method) and indirect method (heat loss). The experimental method carried out in this study was to conduct experiments and retrieve data on a 500 MW steam power plant boilers with variations in the ultimate low range coal (LRC) having calorific value of 4200 kcal/kg of coal. By using the experiment data, this paper is to analysis the effect of variations in the percentage of excess air to unburn carbon and the efficiency of the boilers. The results of the data were then analyzed. And giving that the most optimum value of excess air to produce the lowest unburn carbon value in the 500 MW power plant with 4200 calorific value coal is 10%.

The supercompression of matter caused by gravitational coupling, or self-gravitational forces, leads to density growth by several orders in magnitude. Keeping in mind the importance of self-gravitation in astrophysical processes like supernovae star evolution we consider it reasonable to develop a numerical technique based on the consistent approximation to the terms describing gravitational energy transfer into the kinetic energy of a matter in the star along its life cycle. In the paper, we propose an integrally-consistent difference scheme that utilizes the method of support difference operators thus providing a possibility to conform the balance between kinetic and gravitational energy increments or losses. According to this method, we use the result of the total gravitational energy varying and construct the symmetrized strain rate tensor as the base operator. The result of varying the gravitational energy of the system is a discrete convolution of the Newton gravitational tensor in the difference media under study, which exhaustively answers all the gravitational processes unfolding against the background of the hydrodynamic motion of matter. The symmetrized strain tensor governs the kinematic motion in a considered system. The conjugate operator related to the convolution of these tensors automatically gives the approximation to the gravitational forces acting in the interior of the balance volume of the difference model built via the support operator approach.

Nowadays every industrial company needs to decrease the materials waste and increase their recyclability, especially in the composite manufacturing field, where the environmental effects are a relevant aspect. In order to produce high quality composite pipes via autoclave with high flexibility in terms of producible shapes, an interesting solution is the use of gypsum as material for the patterns. In this case, the easiest and fastest procedure to remove the gypsum patterns would through its immersion in water involving large amount of wasted gypsum to dumps. Therefore, this paper aims to make more eco-friendly the production of GFRP air pipes by reducing the raw material and to make in the same time faster and more recyclable the removing process of the gypsum patterns. For this purpose, a vegetable protein with foaming power was added to the gypsum mixture in order to produce lighter gypsum and reduce the raw material. In addition, to remove the gypsum patterns also allowing their recyclability, an innovative vibration technique was proposed. In this technique, a vibration load was applied to the gypsum pattern in order to destroy it without damage the GFRP sample. The gypsum pieces are then available for the recycling, decreasing the amount of wasted gypsum to dumps. The feasibility of the process was investigated and the mechanical properties in terms of flexural and compression strength, before and after a recycle for both the conventional gypsum and the foamed ones, were studied.

At present, the fault location technology of distribution network mainly relies on FTU, which is divided into direct method and indirect method. The direct method is mainly matrix method, and the indirect method is mainly based on AI algorithm. The matrix method can not locate the fault correctly when the FTU is disturbed and other reasons cause the failure information to be missed. So there are some problems in fault location of distribution network using matrix method (direct method). To solve this problem, based on the traditional particle swarm optimization (PSO) algorithm, this paper constructs a binary particle swarm optimization (PSO) algorithm model to realize fault location of distribution network, and uses MATLAB to verify the simulation example. The results show that the algorithm has the advantages of good convergence, high stability and excellent fault tolerance.

Jute fibre reinforced polymer composite (JFRPC) is one of the natural fibre composites that have recently become attractive used in automobile, aerospace, buildings and other industrial applications due to their lightweight, less cost, biodegradability and easy to fabricate. It becomes necessary to know the material properties and dynamic characteristics of natural fibre reinforced composites to use them effectively for engineering applications. This paper presents numerical and experimental studies of dynamic characteristics of jute fibre reinforced polymer composites for the estimation the material properties. Finite element method (FEM) and impulse excitation technique (IET) were used to determine the natural frequency value of a plate JFRPC. The result shows that the natural frequency is significant and applicable for mechanical properties identification especially modulus of elasticity (E), modulus of rigidity (G) and Poisson ratio (µ) of a jute fibre reinforced polymer plate. This technique is expected to predict the mechanical properties of other materials and prospective as non-destructive evaluation approaches.

Remote satellite imaging provides vital information for observing number of applications such as, land region detection and urban area classification. This paper proposed a novel approach for Classification and extraction of texture features from high resolution satellite images dataset. Preprocessing is done for satellite sensing image using Hilbert matrix filter and Modified Hilbert matrix filter. Then the texture features are extracted from the Hilbert image and Modified Hilbert image using Gray Level Co-occurrence Matrix (GLCM). Finally, obtained features are classified using Decision tree and Random Forest and the accuracy, precision, recall and F-measure is analyzed for performance evaluation.

In this paper, we investigate the optimal conditons for reinsurance models by minimizing the risk exposure of an insurer under the criteria of value at risk (VaR) and ruin probability. We assume that the reinsurance premium is evaluated according to the expected value principle. We also consider two reinsurance models which are the quota-share and the stop-loss reinsurance models. Under the assumption that the loss is exponentially distributed, we develop conditions for optimality of such reinsurance designs.

In “Construction of some new families of Apostol-type numbers and polynomials via Dirichlet character and p-adic q-integrals Turk J Math (2018) 42: 557-577”, we defined some new families of numbers and polynomials related to the Dirichlet character of a finite abelian group. In this paper, we investigate some properties and relations for these numbers and polynomials with their series representations and generating functions. By using functional equations of generating functions with their differential equations and series representations of these numbers and polynomials, we derive some formulas including recurrence relations, combinatorial numbers, combinatorial sums and special numbers and polynomials. By using p-adic integral method, we also derive p-adic series representations of these series representations of these numbers and polynomials.

In this paper, a damage predicting form is developed using fuzzy logic techniques. An earthquake damages the building severely. In order to avoid and relieve devastation, it is essential to frame a disaster attentiveness plan according to the results of damage prediction. It is more coherent to deal with earthquake-related damage forecasting problems using fuzzy logic, as there be plenty of unclear and fuzzy concepts in damage predicting problem and relations involving concerning factors have confusing nature. The model is formulated by various parts “IF… THEN” approximate reasoning.

Blended learning combines face-to-face and online learning, this innovation gives students the opportunity for various levels of interactive learning so that it is far more varied and effective. Mixed learning approaches for environmental chemistry courses are presented. This paper tries to see how the patterns of students in implementing learning in blended learning, try to find out what kind of learning media they like and how they access it. There are twenty-nine students who participate in environmental chemistry courses. Mapping patterns using a qualitative approach. Traditional lectures were replaced by online learning packages, which were supported by formative on-line assessments and presented various learning content activities including, videos, e-books, sharing, and animation media to facilitate the learning process. This study collects participant behavior during a mixed learning course. in addition this article tries to identify interactions between the duration when participants enter the class, access content and final results. A significant pattern was found between the amount of content access and the results of the final test, where participants with low access did not have better results than participants who had high access. Media with too much text such as leaflets are not liked by participants, media with animations and illustrations such as animated videos are very popular and have high access. According to the test results and the number of access to online courses can prove that the level of access will affect the effectiveness of the course in blended learning.

The simulation of compressible multi-fluid flows receives increasing attention, thanks to extensive engineering applications, but there are still many bottleneck problems remain unresolved due to the presence of singularities (shocks, material interfaces, vortices and other discontinuities etc) in flows, which arises notorious diffculties in all aspects of theoretical justification, numerical analysis and scientific computation. In contrast with single-fluid problems, the treatment of material interfaces become an extremely controversial issue in terms of numerical modeling and numerical methods besides conventional shocks and rarefaction shocks. In this paper this topic is reaccessed and a family of temporal-spatial coupled high order accurate schemes are introduced. The temporal-spatial coupling distinguishes these schemes from the methods of line (e.g. RK-WENO, RK-DG) and implicitly includes many fundamental properties such as thermodynamical consistency, multi-dimensionality and symplecticity. The generalized Riemann solver is adopted to provide high order accurate numerical fluxes and reflect “true” dynamical processes.

In the paper, the problem to find statistics of the response of structures with unilateral constraints when the structural pattern is affected by some uncertainty, is approached. In particular, the case of the elastic beam supported by an underlying rigid soil is investigated, under the assumption that the surface of the soil is not perfectly known, but is described by a suitable random process. It is shown that if the beam is discretized into a number of finite beam-elements, and only the ordinates of the soil profile under the nodal points are significant, the problem can be solved by the evaluation of a multidimensional integral. In most cases a Monte-Carlo procedure with “importance sampling” proves to be very efficient for numerical calculation of the above integral.

Using the integrable deformations method for a three-dimensional system of differential equations, in this paper we give integrable deformations of a known nonlinear monetary system. We study some dynamic properties of the system that is obtained by considering particular deformation functions. Moreover, we point out a chaotic behavior of this particular system.

Within the Collaborative Research Centre 1153 “Tailored Forming“ a process chain for the manufacturing of hybrid high performance components is developed. Exemplary process steps consist of deposit welding of high performance steel on low-cost steel, pre-shaping by cross-wedge rolling and finishing by milling.Hard material coatings such as Stellite 6 or Delcrome 253 are used as wear or corrosion protection coatings in industrial applications. Scientists of the Institute of Material Science welded these hard material alloys onto a base material, in this case C22.8, to create a hybrid workpiece. Scientists of the Institut fur Integrierte Produktion Hannover have shown that these hybrid workpieces can be formed without defects (e.g. detachment of the coating) by cross-wedge rolling. After forming, the properties of the coatings are retained or in some cases even improved (e.g. the transition zone between base material and coating). By adjustments in the welding process, it was possible to apply the 100Cr6 rolling bearing steel, as of now declared as non-weldable, on the low-cost steel C22.8. 100Cr6 was formed afterwards in its hybrid bonding state with C22.8 by cross-wedge rolling, thus a component-integrated bearing seat was produced. Even after welding and forming, the rolling bearing steel coating could still be quench-hardened to a hardness of over 60 HRC. This paper shows the potential of forming hybrid billets to tailored parts. Since industrially available standard materials can be used for hard material coatings by this approach, even though they are not weldable by conventional methods, it is not necessary to use expensive, for welding designed materials to implement a hybrid component concept.

In this paper we prove the cube difference labeling of some special graphs such as arrow graphs (Ant), Double arrow graphs (DAnt), Pyramid Pyn, Hanging pyramid (HPyn), H-graph, Hn ⊙ Pm, Hn⊙K1,m¯ and Duplication of all edges of Hn are cube difference graphs.

Lightweight design, lower fuel consumption and easier recyclability are the current concerns of the automotive industry as a response to the increasing demand for energy saving and better environmental impact of the transportation section. This framework was the opportunity to develop multi-layer materials, as an alternative to the high-density homogeneous metal sheets, maintaining the structural properties of the component. The multi-layer materials, known as composite sandwich or hybrid materials, are composed of outer metal sheets with reduced thickness and a polymeric matrix core (low density), in which high specific strengths are achieved. However, the lack of studies and information about the behavior of these non-homogeneous materials posed new challenges, either with regard to their use in the sheet metal forming processes, but also when performing material mechanical characterization. This paper presents the problems faced with bending test and springback analysis of a sandwich metal polymer sheet, compared with a high strength low alloy steel (HSLA420). Experimental tests and corresponding numerical simulations were performed using the press brake air bending process and a Numisheet benchmark test, unconstrained bending test, at room temperature, using the same experimental conditions for both materials. The numerical simulations were performed using finite element modeling. The results show that the sandwich material have problems on the structural integrity for a lower punch radius, on the outer surface (tension side). Additionally, the comparison of springback behavior showed that there is no significant difference between the materials in the study, although the non-homogeneous sandwich material presented a lower springback.

In servo control system, the current loop as the inner loop directly affects the performance of the whole control system. In engineering practice, there are delays in forward and feedback channels of current loop due to arithmetic, power switch operation, sampling and so on. Those delays will reduce the bandwidth of current loop. This paper firstly analyses and demonstrates the effects of forward channel delay and feedback channel delay to suppress the bandwidth of current loop, and then analyses the current loop in actual situation. By using the typical elements approximate processing and the closed-loop dominant pole processing method, the current loop model is simplified based on the actual situation, and the analytical solution of bandwidth related to delays is obtained. Through the analytical solution, the capability of forward channel delay and feedback channel delay in current loop bandwidth inhibition can be directly expressed, which provides a theoretical basis for practical engineering to expand current loop bandwidth.

In this paper, a three-dimensional CFD simulation of the air flow in a 14.4 MVA hydrogenerator in service at EDF is performed. This machine was selected because it presents a large axial temperature gradient in the stator core that imposes some load limitations. The computational domain includes all the main components of the hydrogenerator (rotor, stator, frame and housing) except for the coolers since they would require a much higher meshing and computational effort. The numerical results show a significant axial flow maldistribution across the stator ducts with a flow blockage in the bottom duct that is most probably responsible for the overheating observed in the bottom region of the stator core. This finding has been validated through air flow measurements that were performed at the outlet of several stator ducts using a custom sensor developed at Hydro-Quebec’s Research Institute. Furthermore, the computed windage losses in the hydrogenerator were compared with the measured ones and a discrepancy lower than 1% was found. Consequently, this numerical investigation has successfully proven the capability of a CFD model to reproduce the ventilation anomalies present in an operating hydrogenerator, as long as the input parameters of the model are carefully fixed. Moreover, this approach can provide engineers with useful information that could help them solve cooling issues.

One of the key components in an electric vehicle is brushless direct current (BLDC) motor controller. At present, it is difficult to match a self-made motor controller with several different BLDC motors available in the global market. One of the reasons is that the Hall sensors’ configuration is not well informed. Another reason is the motor parameter’s values used in the controller are not well suited with the real physical conditions of the motor. This study aims to design an intelligent reconfigurable BLDC motor controller. In this paper, a method for automatic commutation configuration and automatic parameter values detection is presented. The Hall sensors and motor phases configurations are identified. The BLDC motor parameter values are detected automatically using mathematical models. Those parameters include internal resistance, inductance, coefficient of back electromotive force (BEMF), torque coefficient, friction coefficient, and moment of inertia. Experimental results of the automatic commutation configuration and parameter values detection are presented. Those results were used to develop a current controller. Further experimental results indicated that the method could be implemented in a BLDC motor current controller.

In this paper, a spectral-based numerical result is presented for the fully developed two-dimensional flow of viscous incompressible fluid through a rotating curved rectangular duct. The bottom wall of the duct is heated while cooling from the ceiling. A rotation of the duct about the centre of curvature is imposed in the positive direction for the constant Dean number Dn = 1000 over a wide range of the Taylor number 0≤Tr≤2000. First, solution structure of the steady solutions is obtained by the Newton-Raphson iteration method. Then, we investigated unsteady solutions by time evolution calculations justified by power spectrum of the solutions, and it is found that when there is no rotation, the flow is chaotic but as the rotational speed increases, the chaotic flow turns into steady-state flow through periodic or multi-periodic flows. This study shows that combined effects of the centrifugal and Coriolis forces counteract each other in a nonlinear manner which results in to turn the chaotic flow into steady-state flow. The present study demonstrates the role of secondary vortices on convective heat transfer which shows that secondary flow enhances heat transfer in the flow. Typical contours of secondary flow patterns and temperature distribution are also obtained at several values of Tr, and it is found that the unsteady flow consists of two- to eight-vortex solutions if the duct rotation is involved in the present case.

Ever since the process of industrialization started, social scientists have been consistently expressing fears that the world is moving towards joblessness for all low level manual skilled/unskilled workers. Recently, computerization and robotics have added to this fear like never before. Smart and innovative ways of using computers, robots and internets have threatened to displace even those humans who are engaged in the high-middle level management cadre. Teachers are feeling threatened as online courses have started flooding the internet. With promising research in the area of artificial intelligence and robotics being reported frequently, even high level cadres along with the middle-level management cadres are feeling unsecured about their jobs. Automation is widely understood to be targeting at displacing humans from their jobs. Are we moving towards a jobless world where there will be no jobs left for humans? This paper aims at finding an answer to such concerns first by finding a similarity between a thermodynamic system and a social/commercial establishment and then applying the laws of thermodynamics to such systems. It will be interesting to compare a social/business establishment with those of a thermodynamic system and identify isomorphism associated with both the systems. There is a possibility of application of laws of thermodynamics in a commercial system and open up a new field of study.

The elastic scattering process Λp → Λp offers insights on multiple problems in nuclear physics. SU(3)F symmetry implies a close agreement between the Λp and pp scattering cross sections. The Λp elastic scattering cross section can also illuminate the structure of neutron stars. A data-mining project was started using multiple CLAS data sets taken for other purposes with photon beams on a long liquid hydrogen target. A Λ produced in a process such as γp → K+ Λ can interact with a second proton inside the target before either decaying or leaving the target. The good angular acceptance and momentum resolution of CLAS make it well-suited for this type of analysis, even though it was not designed for such a measurement. The scattered Λ can be identified from the π− p invariant mass. The four-vector of the initial Λ is then reconstructed in the process Xp → Λp, which shows a strong peak at the Λ mass with roughly twice the number of events as the existing world data sample. This observation opens up the possibility of other measurements using secondary beams of short-lived particles. This paper will discuss the current status of the analysis, and our plans for future work on this project.The elastic scattering process Λp → Λp offers insights on multiple problems in nuclear physics. SU(3)F symmetry implies a close agreement between the Λp and pp scattering cross sections. The Λp elastic scattering cross section can also illuminate the structure of neutron stars. A data-mining project was started using multiple CLAS data sets taken for other purposes with photon beams on a long liquid hydrogen target. A Λ produced in a process such as γp → K+ Λ can interact with a second proton inside the target before either decaying or leaving the target. The good angular acceptance and momentum resolution of CLAS make it well-suited for this type of analysis, even though it was not designed for such a measurement. The scattered Λ can be identified from the π− p invariant mass. The four-vector of the initial Λ is then reconstructed in the process Xp → Λp, which shows a strong peak at the Λ mass with roughly twice the number of events as the existing world data sample. This observation opens up the possibi...

Collision welding is a promising material closed joining process for metals without any additional heat. Although the process is already industrially applied, the working mechanisms of bond formation have not yet been completely understood. Less process understanding results in lower process reliability. Therefore, the design of new component joints and welding processes has to be carried out mostly experimentally with a high effort in order to ensure a high reliability.In this paper, the formation of the weld interface is investigated for copper-copper-joints, which has interesting applications in the field of future electro mobility. Especially the full formation of the weld interface is critical in lower energy welding processes like electromagnetic pulse welding. For this purpose, welds with different collision angles and impact velocities were produced by a purely mechanical driven test rig and observed by a high speed camera. Subsequently, the welded areas were analyzed by an ultrasonic scanner. The results show a dependence of the size of the welded area on the collision angle and the impact velocity. It is shown, that the impact velocity correlates with the available energy for the bond formation. Moreover different types of weld interfaces can be identified from the measurements.

The main objectives of this paper is to verify, for the first time, the possibility to model a solar optimizer developed in laboratory and connected to an un-shaded photovoltaic (PV) module, where his behaviors have been simulated by a commercial software, the Proteus Design Suite of Labcenter Electronics. For two different PV modules (a roof PV module and a PV module dedicated to 12V battery recharge) software simulations of I-V characteristics are compared to experimental curves. The very small differences between simulation and experimental results lead us to consider that such modelling is realistic for simple configuration, namely a solar optimizer supplying a single load. In a second time an association of two solar optimizers by output parallel coupling is designed and simulated with Proteus software. Large data files produced by Proteus software simulations require to reduce duration of studied phenomena, or else errors like insufficient memory may appear. Simulated behaviors as current injection of small PV module may be encountered when the physical conditions are not gathered, which is very astonishing, while other behaviors comply perfectly with physical reality. So, to verify the real behavior of parallel coupling an experiment is designed to highlight variations of electrical variables like PV module voltage and current without forgetting load voltage. This last experiment confirms effectively how PV modules with different specifications influence each other. Partial mismatch between simulation and experiment implies future strengthening in modeling process with Proteus software, expecting to verify that reason is not the complexity of the parallel association when electronical circuit begins to be heavy to treat. As other tracks of investigation, DC-DC converter model has to be improved, particularly with a more precise characterization of the autotransformer which is the key component of high voltage step-up. Finally, additional experiments have to be also planned with various loads (pure resistors and electronical load) to confirm or deny phenomena encountered when using particular load as incandescent lamps.

In this paper, a distributed generation connected IEEE.9 node network is used as an example for harmonic analysis of power flow. Based on harmonic balance algorithm, the equivalent network of power system is established to calculate harmonic power flow in MATLAB environment. Then the harmonic parameters such as harmonic voltage of each node and its distortion rate are obtained. The distribution of harmonic components in power network is acquired, which provides theoretical basis for harmonic suppression.

This paper presents a case study in which a Ground penetrating radar (GPR) system consisting of two antennas was used to investigate the condition of a bridge deck in central Sicily. The acquired data were analyzed for identifying the asphalt overlay thickness, concrete cover depth and deck thickness and location of the rebar reinforcement. The GPR survey was complemented with site investigation on layer thicknesses for calibration/verification purpose and complemented with a Terrestrial Laser Scanning system (TLS) to verify the bridge design characteristics (i.e., bridge deck curvature) information. The study shows that this methodology has significant merits on accurately assessing such bridge deck components when bridge design records are non-existing, and by using non-invasive methods such as laser scanning and GPR. The great advantage provided by the TLS technique is the possibility to obtain a 3D output model of the scanned element with the accuracy of the best topographic instruments in order to improve and verify GPR data interpretation.

Geopolymers can be considered as competitive construction materials to cement-based materials. It is mainly due to their high strength, good chemical resistance, thermal stability and favorable development of hydration heat at early age. A reasonable amount of electrically conductive admixtures close to the percolation threshold enhances electrical properties of geopolymers which leads to their potential utilization in self-heating applications. In general, electrical and thermal conductivity is essential for an effective heat evolution and distribution through the material. Sufficiently high electrical conductivity ensures evolution of Joule’s heat initiated by acting of a power supply, whereas sufficiently high thermal conductivity ensures effective spreading of the generated heat. To assess the self-heating ability of such materials and effectiveness of their self-heating, it is necessary to experimentally determine electrical and thermal properties. In this paper, basic physical, electrical and thermal properties of geopolymers with different dosages of electrically conductive carbon black admixture are measured. Basic physical properties are determined by the gravimetric method, DC electrical properties by the 4-probes method and thermal properties by the pulse method. Addition of 10 wt.% of CB to the reference geopolymer is found to lead to a significant increase of electrical conductivity at the cost of a decrease of thermal conductivity. Nevertheless, geopolymer enhanced in such a way can be considered as a promising self-heating material.