18 Articles Published

1. FIVE UPCOMING TECHNOLOGY TRENDS IN ENTREPRENEURSHIP

Authors: MLADEN RAJKO

Abstract: Each new era brings new trends in entrepreneurship, and those who manage to recognize them and adjust for their benefit become successful entrepreneurs. Over the last 100 years, the society has gone through an industrial and technological revolution, and new inventions and the appearance of new trends in biology, chemistry, IT, technology, engineering, processes, communication, management and economy are getting faster and faster and people have to adapt themselves ever faster. Business is evolving online at breakneck speed. Enterprising and forward-thinking entrepreneurs will follow the hottest trends and find ways to capitalize on them. Every great tech company in existence today is there because someone saw an opportunity and capitalized on it, and the future promises to bring many more great companies to fruition. Whether you are interested in building an online empire yourself, or in investing in progressive companies, here are five trends that offer unlimited potential.

Keywords: biology, chemistry, IT, technology, engineering, processes, communication, management and economy

Pages: 80 - 81 | DOI: 10.15224/978-1-63248-023-1-99

2. DRILLING SIMULATIONS USING A 3D CAD SYSTEM

Authors: PANAGIOTIS STRATAKIS , KONSTANTINOS KOKKINOS

Abstract: Drilling is considered to be one of the mostly used processes for holemaking. Researchers have followed different approaches for the drilling simulation. Different mathematical tools offer a great deal of help in describing difficult 3D equations in space. Due to the continuous onward usage of CAD systems in all industries, new applications based on the Application Programming Interface (API) that each one offers, are under development. The present paper uses a general purpose CAD system and its API in order to create a kinematic model that parametrically controls the twist drill tool geometry. Introducing different tool parameters and cutting conditions, a series of 3D solid models for the tool, the workpieces and the undeformed chips are created and the resulted thrust forces can be predicted in both the main edges and the chisel edge. The proposed methodology is experimentally verified and provides the basis for a series of new applications in manufacturing

Keywords: drilling process, CAD, simulation

Pages: 1 - 5 | DOI: 10.15224/978-1-63248-022-4-40

3. MATLAB/STATEFLOW BASED MODELING OF MPPT ALGORITHMS

Authors: ALI DURUSU , ISMAIL NAKIR , MUGDESEM TANRIOVEN

Abstract: Maximum power point tracker (MPPT) is an important part of photovoltaic system for extracting maximum power from photovoltaic array. MPPT is basically a dc-dc converter. MPPTs are controlled by MPPT algorithms and a number of MPPT algorithms are proposed in literature. Some of the proposed MPPT algorithm is commonly used in applications. In this paper, four commonly used MPPT algorithms (Perturbation and Observe, Incremental Conductance, Only Current Photovoltaic and Short Circuit Current) are modelled with Matlab/Stateflow. These algorithms are tested with Matlab/Simulink model and results are presented.

Keywords: matlab/stateflow model, mppt algorithm, pv system

Pages: 6 - 9 | DOI: 10.15224/978-1-63248-022-4-41

4. ESTIMATION OF QUANTITIES OF WASTE MATERIALS FOR PHOTOVOLTAIC INSTALLATIONS IN CRETE ISLAND

Authors: ALEXANDRA CHATZIKOKOLAKI , ANASTASIA KATSAMAKI , MELETIOS RENTOUMIS , NIKOLAOS BILALIS

Abstract: This paper aims to estimate the amount of waste materials for photovoltaic (PV) installations in Crete Island. Crete is the largest Greek island and constitutes the largest autonomous power system in Greece. The analysis includes the impact of the basic components of a PV system: PV panels, PV mounting system, cables, and inverters. The results show that significant amounts of waste materials will be produced in the period 2030-2038. Moreover, this study generalizes the results for the entire Greek territory.

Keywords: crystalline silicon photovoltaics, recycling, waste electrical and electronic equipment (WEEE), Crete

Pages: 10 - 14 | DOI: 10.15224/978-1-63248-022-4-42

5. TOPOLOGY BASED AUTOMATIC TAPN MODEL GENERATION FOR RAILWAY SYSTEMS

Authors: GALIP CANSEVER , IBRAHIM SENER , ILKER USTOGLU , MUHAMMED ALI NUR OZ , OZGUR TURAY KAYMAKCI

Abstract: The use of formal methods in modeling and designing of railway transportation system is strongly recommended by CENELEC EN 50128 standart. Nowadays, the development of formal models of railway systems is completely performed manually. In this study, a software tool was developed by using C# programming language for automatic generation of the formal models of railway stations. The specially developed software tool generates the Timed-Arc Petri Net models, which is a formal method and highly recommended by the relevant standart, of the station components separately from the station topology.

Keywords: formal methods; railway; automatic generation; station topolog

Pages: 15 - 19 | DOI: 10.15224/978-1-63248-022-4-43

6. EFFECT OF TAPERED HOUSING ON THE AXIAL STRESS DISTRIBUTION IN A STUFFING BOX PACKING

Authors: ABDEL-HAKIM BOUZID , MEHDI KAZEMINIA

Abstract: The sealing performance of a packed stuffing-box used in pumps and valves is strongly dependent on the distributions of the axial stress and the contact pressure between the packing rings and the side walls. In particular the stress state of the bottom packing ring that is in contact with the internal fluid which is at its minimum is the leak controlling parameter. This minimum axial stress and its resultant radial stress control the pore size and therefore dictate the quantity of leak that passes through the packing rings. This paper presents a new design feature that improves the stress distributions. The introduction of a variable gap between the packing and the side walls helps producing a more uniform distribution of the stresses in the packing rings while increasing the minimum stress. An analytical model that takes into account the effect a tapered housing on the distribution of the axial stress in a stuffed packing box is also developed. The analytical model is validated by com

Keywords: Packed stuffing-box, analytical modelling, sealing peformance, axial stress, tappered housing

Pages: 20 - 25 | DOI: 10.15224/978-1-63248-022-4-44

7. INVESTIGATE THE POSSIBILITY OF USING CARBON ONION NANOLUBRICATION WITH DLC CUTTING TOOL TO REDUCE THE MACHINING POWER CONSUMPTION

Authors: AHMED. A. D. SARHAN , M. E. OOI , M. HAMDI , M. SAYUTI

Abstract: Due to rapid consumption of world's fossil fuel resources and impracticality of large-scale application and production of renewable energy, the significance of energy efficiency improvement of current available energy modes has been widely realized by both industry and academia. In the CNC machining field, the key solution for this issue is by increasing the effectiveness of the existing lubrication systems as it could reduce the power required to overcome the friction component in machining process. For more improvement, introducing the nanolubrication could produce much less power consumption as the rolling action of billions units of nanoparticle in the tool chip interface could reduce the cutting forces significantly. In this research work, the possibility of using carbon onion nanolubrication with DLC cutting tool is investigated to reduce the machining power consumption. Carbon onion nanolubrication has been successfully developed with high tribology performance and mixed with or

Keywords: carbon onion nanolubrication, machining power consumption, DLC cutting tool

Pages: 26 - 31 | DOI: 10.15224/978-1-63248-022-4-45

8. COMPUTATIONAL AND PARAMETRIC STUDY OF AERODYNAMIC COEFFICIENTS OF FIXED-WING MICRO AERIAL VEHICLES

Authors: JEEVA J , K SUDHAKAR , SMRITI NANDAN PAUL

Abstract: The work carried out in this paper is aimed towards CFD study and empirical determination of parameters that effect the lift and drag coefficients of fixed wing micro aerial vehicles. Empirical formulae are devised for calculating these aerodynamic coefficients in order to alleviate the computational cost incurred by conventional high fidelity software tools. Two of the most widely used planform shapes for fixed wing micro aerial vehicles i.e. rectangular and Zimmerman shapes are chosen for study with cambered low Reynolds number airfoil E61. The results obtained using the empirical formulae are compared with that of ANSYS FLUENT[1] software. Moreover, flat plate results from wind tunnel experimentations by Thomas Mueller et al.[2] have been compared with corresponding FLUENT[1] CFD results as well as with the empirical formulation.

Keywords: Micro Aerial Vehicles (MAV), CFD Fluent[1] , Wind Tunnel Test, Lift Coefficient, Drag Coefficient, Advance Ratio, Wetted Area Ratio Introduction

Pages: 32 - 36 | DOI: 10.15224/978-1-63248-022-4-46

9. CAD-BASED SIMULATION AND SURFACE TOPOMORPHY PREDICTION IN BALL-END MILLING

Authors: ARISTOMENIS ANTONIADIS , ARISTOMENIS ANTONIADIS , CHARA EFSTATHIOU , DIMITRIOS VAKONDIOS

Abstract: Optimization of ball end milling processes has been an area of great interest, on the grounds that such processes are extensively used for precision and high-efficiency machining of freeform and complex surfaces. The selection of optimal cutting conditions, involved in such processes, can be accomplished by utilizing models that simulate the kinematics of the milling process, therefore allow the analytical prediction of the produced surface topomorphy and quality. The present study introduces a model developed for the simulation of milling processes, integrated in a commercial CAD software. Furthermore, several ball-end milling of Al7075-T6 experiments were carried out under various cutting conditions, so as to verify the completeness and accuracy of the above mentioned model, through the comparison of the predicted and the machined surface. According to the validation outcomes, the developed model demonstrates high computational efficiency.

Keywords: ball-end milling, cad-based simulation, surface topomorphy

Pages: 37 - 41 | DOI: 10.15224/978-1-63248-022-4-47

10. OPTIMAL CUTTING CONDITIONS IN BALL-END MILLING OF COMPLEX SURFACES TAKING INTO ACCOUNT THE DESIRED SURFACE ROUGHNESS

Authors: ALEXANDRA CHATZIKOKOLAKI , ANASTASIA KATSAMAKI , CHARA EFSTATHIOU

Abstract: Ball-end milling is widely used as a surface finishing process. The selection of the proper cutting conditions, that is the spindle speed as well as the feed rate, is crucial for the optimization of the process. This selection is made according to the cutting speed, which is specified by the cutting tool and workpiece materials. In the case of ball-end milling of complex surfaces, the cutting speed varies depending on the changing effective diameter at the point of contact between the cutting tool and the workpiece. Therefore the cutting speed does not remain stable during the process, which directly influences the quality of the finished surface. One way to overcome this problem would be to continuously change the rotational speed of the cutting tool according to the variable effective diameter so as to keep the cutting speed constant, yet this solution is not technically feasible. In the present study, an experimental method for the specification of the optimum cutting conditions bas

Keywords: ball-end milling, cutting conditions, surface roughness

Pages: 42 - 46 | DOI: 10.15224/978-1-63248-022-4-48

11. AUTOFRETTAGE OF FUEL INJECTION PIPE

Authors: SEUNGKEE KOH

Abstract: In order to investigate the optimum conditions of the autofrettage process for the fuel injection pipe in diesel engine, different levels of autofrettage pressure, pressure rising time, pressure holding time, and repetition of autofrettage were applied. The autofrettage residual stresses in the fuel injection pipe were experimentally measured by using X-ray diffractometer. As the overstrain level increased, the magnitude of compressive tangential residual stress at the bore increased. It was found that the rising time to the autofrettage pressure, holding time at the autofrettage pressure, and repeated application of the autofrettage pressure had no significant influence on the residual stress distributions in the pipe.

Keywords: Fuel injection pipe, Autofrettage, Residual stress

Pages: 47 - 50 | DOI: 10.15224/978-1-63248-022-4-49

12. COMPARISON OF CHARGE CONTROLLERS ON PV PANEL PERFORMANCE: AN EXPERIMENTAL STUDY

Authors: A. BOZKURT , A. DURUSU , A. ERDUMAN , B. KEKEZOGLU , E. ISEN , O. ARIKAN

Abstract: Nowadays, photovoltaic (PV) systems are widely used because of environmental concerns, electrical energy demand, cost of electricity generation, minimum service cost and support of governments on renewable energy conversion systems. The main drawback of PV systems is energy conversion efficiency. The two parameters that PV system output power depends on are solar radiation and temperature. Therefore, charge controllers are utilized to increase system efficiency. In this study, performance of 320 W solar panel groups which are controlled by two different charge controllers are investigated. The influence of charge controllers on system performance is presented with the analysis of obtained data. Experimental study is realized on a stand-alone energy system that is located in Davutpasa Campus of Yildiz Technical University.

Keywords: Charge controller, photovoltaic panels, PV performance, stand-alone system

Pages: 51 - 55 | DOI: 10.15224/978-1-63248-022-4-50

13. DEVELOPMENT OF A CONTACT BASED HUMAN ARM MOTION ADAPTATION SYSTEM

Authors: P.V.MANIVANNAN , VARUN NALAM

Abstract: This paper presents the development of a device which can analyze and replicate Human motion on different robotic devices. The system uses contact based sensors which gather data related to position, velocity and acceleration of different joints of human arm and transmit it to a central processor which adapts the data to perform necessary motion on the robot. The system can be used in daily activities and industry for training robots without much knowledge.

Keywords: Motion Adaptation, Control of Robotic Arms, Wearable Control Devices

Pages: 56 - 60 | DOI: 10.15224/978-1-63248-022-4-51

14. THE ROLL DYNAMICS FOR HIGH SPEED PAPER MANUFACTURING

Authors: R. WHALLEY

Abstract: The transverse, dynamic deflection of high speed, wide faced, composite tubular rolls is investigated. General procedures are proposed enabling the analysis of inter-connected units comprising both distributed parameter and rigid, point-wise models. Modelling methods, eliminating intermediate variables are employed facilitating the realization of an overall system, input – output representation. An illustrative study, detailing the analysis and evaluation process is presented. A high speed, MG paper making machine, table roll application is considered. Whirling conditions and the effect of this problem on sheet quality and manufacturing output is commented upon.

Keywords: wide, tubular, rolls, whirling, speed

Pages: 61 - 65 | DOI: 10.15224/978-1-63248-022-4-52

15. THE ROLL DYNAMICS FOR HIGH SPEED PAPER MANUFACTURING

Authors: R. WHALLEY

Abstract: The transverse, dynamic deflection of high speed, wide faced, composite tubular rolls is investigated. General procedures are proposed enabling the analysis of inter-connected units comprising both distributed parameter and rigid, point-wise models. Modelling methods, eliminating intermediate variables are employed facilitating the realization of an overall system, input – output representation. An illustrative study, detailing the analysis and evaluation process is presented. A high speed, MG paper making machine, table roll application is considered. Whirling conditions and the effect of this problem on sheet quality and manufacturing output is commented upon.

Keywords: wide, tubular, rolls, whirling, speed

Pages: 61 - 65 | DOI: 10.15224/978-1-63248-022-4-52

16. MACHINERY DRIVES AND DYNAMIC STRESSES

Authors: A. ABDUL-AMEER

Abstract: Distributed-lumped parameter modelling methods are employed in the analysis of manufacturing machine drives comprising rotors, bearings and shaft arrangements for variable speed process systems. Analysis procedures enabling the computation of the torsional shear stress and velocity response of these systems are outlined and block diagram representations are formulated. The dynamic stresses for machine drive arrangements following deterministic input changes are computed. Typical rotor-shaft assemblies are investigated illustrating the peak stress levels encountered.

Keywords: distributed, lumped, modelling, dynamic, stress

Pages: 66 - 70 | DOI: 10.15224/978-1-63248-022-4-53

17. FLUID DYNAMICS OF BRITTLE COLLAPSE

Authors: DOMENICO M. DORONZO

Abstract: When a skyscraper collapses to the ground, the coarsest fragments are rapidly deposited close to the impact zone, whereas the finest counterpart is loaded in a fast and unsteady turbulent flow. Similarly in nature, collapses of volcanic columns, and entire sectors of explosive volcanoes generate thick deposits of coarse material at impact with the ground, instead the fine material is suspended from there on over the landscape to be re-deposited far away in thin deposits. The videos of the spectacular controlled demolitions of hotels and casinos performed at Las Vegas (Nevada, USA) in the recent past definitely reveal the collapse fluid physics of fragmented material. The fragmentation, which is necessary for such a collapse, can make a solid or granular column to powder particles of the size of natural clay or volcanic ash. These particles are mainly transported in suspension by the turbulent flow that is triggered after collapse. The phenomenon of fragmentation is characteristic of ar

Keywords: collapses, volcanic columns, nature, sectors, explosive volcanoes

Pages: 71 - 71 | DOI: 10.15224/978-1-63248-022-4-98

18. OVERVIEW ON SINGLE-PHASE NATURAL CIRCULATION LOOPS

Authors: MARIO MISALE

Abstract: Analytical and experimental studies on singlephase natural circulation loops (thermosyphons - NCL ) have been performed in the past years by several authors,. However the problem of the stability of the loops, that is of interest in many industrial applications, cannot be considered solved. The present paper is focused on the experimental aspects that could be interesting in the study of these thermal systems. In particular, the following NCLs aspects will be discussed: applications, models, thermo-hydraulic behaviour, and influence of loop size. Finally a broad reference list is cited

Keywords: natural circulation, single-phase, instabilities, nanofluids)

Pages: 72 - 83 | DOI: 10.15224/978-1-63248-022-4-101