bluuebunny/crossref_metadata_2025_split huggingface dataset:
Instrument for selecting and evaluating suppliers in small and medium-sized metalworking enterprises in Cartagena, Colombia
Authors: L Álvarez V , C Gualdrón G , R Padrón C , L Sampayo C 
Published: March 2020

Abstract
The objective of this investigation is the definition of a practical tool that helps to improve the selection process and evaluation of suppliers in small and medium-sized metalworking enterprises in Cartagena city. For this purpose, a mixed approach methodology was used where data from 30 projects in the sector were mixed, together with related literature, to identify the most relevant factors. Once the information was reviewed, the multicriteria decision method known as the analytic hierarchy process was applied, where the experience, organizational structure, project resources, technical capacity, and previous performance were used as decision-making elements for the processes related to the selection and supplier’s evaluation.
Classification of pluviometric networks located in the region of Bogotá, Colombia using artificial neural networks
Authors: Garrido-Arévalo A R , Agudelo L M , Obregon N , Garrido V M 
Published: March 2020

Abstract
This work presents a methodology for the classification of pluviometric networks using artificial neural networks. For this, the network of stations registered in the Corporación Autónoma Regional de Cundinamarca, Colombia, was analyzed. The network studied consists of 182 stations for the measurement of precipitation and it has a historical series that goes, in some cases, from 1931 to the present. For the classification, three scenarios called types were proposed, in which the number of neurons in the output layer was varied. It was significant that when comparing the results of the different types, the permanence of certain features in the classification was found, indicating the validity of the classification.
Control of a charging station for electric vehicles
Authors: Martín Fernández L , Serra F , Angelo C De , Montoya O 
Published: March 2020

Abstract
A weighted average current control applied to a three-phase inductor-capacitor-inductor grid-connected battery charger for electric vehicles is presented in this paper. The proposed controller is based on a combination of the partial currents of the system (inverter and grid currents), which are feedback into the control loop. Therefore, by using this approach a reduction of the system order is achieved. The proposed controller allows a bidirectional control of the converter currents, thus allowing both, a controlled charge of the battery and the injection of the current with low distortion in the grid. Further, the implemented controller does not needs to measure the inverter currents. The control strategy is validated with simulation results.
Increasing driving range for electric vehicles at sub-zero temperatures by optimizing a hybrid storage configuration using supercapacitors
Authors: Dominguez-Jimenez J A , Campillo J 
Published: March 2020

Abstract
One of the main challenges electric vehicles manufacturers face is the perceived limited operational range of cars, commonly referred to as “range anxiety”. Furthermore, effective range in these vehicles is affected by multiple factors, including driving behavior, battery size, operating temperature, among others. Particularly, Lithium-based batteries the most used in the industry today, experience significant electrochemical changes when operating at sub-zero temperatures, which reduces their overall energy capacity. Furthermore, cycling operation under these conditions, could also severely reduce the batteries’ expected lifetime. This work uses a model-based approach to simulate a reduced current rate from lithium-based batteries, operating at sub-zero temperatures, during high-acceleration modes by including super-capacitors. By adding super-capacitors, the power supplied to the motors from the battery pack during short-time acceleration periods, can be reduced. This approach suggests that the effective range in Electric Vehicles increases by using an optimal hybrid energy storage system. Simulations were carried out to estimate the impact of subzero temperatures on the range of the vehicle. Results showed that the overall range increases with the addition of the the storage system. Furthermore, reduced current rates at sub-zero temperatures would also increase the battery pack’s expected lifetime. These results offer great insights for designing more efficient energy storage systems for electric vehicles.
Power flow solution in direct current grids using the linear conjugate gradient approach
Authors: Montoya O D , Escobar A F , Garrido V M 
Published: March 2020

Abstract
The Colombian power system is being modified by the large-scale integration of renewable energy resources and energy storage systems, in conjunction with the microgrid concept that originates the possibility of alternating and direct current grids or hybrid between them. Here, we propose a classical gradient conjugate method to solve linear algebraic equations without matrix inversions, to address the power flow problem in electrical direct current networks with constant power loads, to contribute with the paradigm of microgrids operated in direct current. This methodology can be applied to the power flow equations since the admittance matrix is positive definite and diagonal dominant which guarantees convergence of the power flow problems. Numerical simulations evidence the applicability of the gradient conjugate method to solve power flow problems in direct current networks with radial and mesh topologies. All the simulations are conducted in MATLAB software version 2017a licensed by the Universidad Tecnológica de Bolivar, Colombia.
Electrical transport through two-dimensional DNA nanostructure
Authors: Paez C J , Ospina R , Garcia-Castro A C 
Published: March 2020

Abstract
In this work, we numerically investigate the transport properties of a square lattice built from disordered deoxyribonucleic acid sequence. To do so, we used an effective tight-binding model to describe the electronic structure, while the current is obtained within a Green’s function framework. We show that the self-assembled DNA structures based-on the disordered sequences display currents, which, by increasing the size of the systems, quickly go to undetectable experimental current values.
Genetic algorithms for mathematical optimization
Authors: García J M , Acosta C A , Mesa M J 
Published: March 2020

Abstract
The inability to find the solution in engineering problems has led to a large part of the scientific community developing indirect and alternative techniques to find optimization problem-solving. Genetic algorithms are looking for models based on the natural and genetic selection process, which optimizes a population or set of possible solutions to deliver one that is optimal or at least very close to it in the sense of a fitting function. In this work, we derive and evaluate a method based on genetic algorithms to find the relative maximum of differentiable functions that are difficult to find by analytical methods. We build a library in Python that includes different components from genetic algorithms. The test problems include finding the maximum or minimum of functions in one and two dimensions.
Aerodynamics and flow pattern performance evaluation of off road vehicle for various velocity range and angle of incidence
Authors: Muruga Lal Jeyan JV , Nair Kavya S , Nair Krishna S 
Published: March 2020

Abstract
It is complex to amplify the significance of flow visualization. This is factual whether the methodology is strictly theoretical, primarily experimental, primarily computational or some combination as is always the most effective. The ability to see flow patterns on and around the device under investigation often gives insight into a solution to an aerodynamic problem. The reasonable mental image of a flow about a body is almost necessary for a researcher to have a useful understanding of an aerodynamic or hydrodynamic problem. We researcher and aerodynamicist believe possibilities of some significant difference in results obtained by computation and mental image and the experimental evidences resolve the uncertainty. In our research primitive variables that describe the flow and qualities are found to be use full in flow visualization phenomena. We resolve this with the concept of path line, stream line, streak line and time line approaches. A selective off road vehicle scaled model is tested by considering all the parameters. A low speed wind tunnel test facility with a calibrated test section size of 200 X200mm, low flow angularity providing acceptable laminar level and smoke tunnel facility is used for experimentations. The scale downed model is rationed with an allowable blockage factor not more than 10% is tested to a velocity range of 10m/s–50 m/s. Entire study and experiments on this Off-Road vehicle aerodynamics bounces adequate results. This experimental results and solutions will be useful for future young researchers in the field of off road vehicle design Aerodynamic analysis, more over this results gave a conceptual study for the person who drives the vehicle about the maximum occurrences, maximum possible drag and side slips over the vehicle.
Effects of secondary injection on the performance of over-expanded single expansion ramp nozzle
Authors: Shanmugaraj Gopinath , Muruga Lal Jeyan J V , Singh Vijay Kumar 
Published: March 2020

Abstract
Scramjets with Single expansion ramp nozzle (SERN) is one of the most promising candidates for an airframe integrated hypersonic vehicle propulsion system. So, studying the performance of the SERN at various flight conditions is very important to improve the overall performance of the propulsion system. The main problem with a SERN is, it tends to exhibit poor performance characteristics at the over-expanded or off-design operating conditions. So, to improve the performance of the SERN at off-design conditions, the present numerical study focuses on using various secondary injection techniques on the cowl and ramp surfaces. The freestream Mach number considered for the current study is 3, and the corresponding nozzle pressure ratio (NPR) for the SERN is 20. The effects of injection pressure, location, and angle on the axial thrust force and normal force are parametrically studied. It is found that the introduction of secondary injection significantly affects the pressure distribution over the cowl and ramp surface. This change in pressure distribution directly reflects on the magnitude of the normal force and axial thrust force generated by the SERN. The secondary injection also influences the shock pattern of the main nozzle flow.
A review on Aerodynamic performance of NACA Airfoil for various Reynolds number
Authors: Mathew Bilji C , Thakan Amit , Muruga Lal Jeyan J V 
Published: March 2020

Abstract
Morphing and shape shifting technologies offer a wide range of applications in airplane design and are complicated to operate effectively with current existing methods. Variable camber wings is a innovative control surface technology designed as aero elastic wing shaping control device which minimizes drag throughout its flight envelope and increases performance in different flight conditions which leads to corresponding increase in airplane flight efficiency. In order to achieve these results one has to rely on different flight actuator configurations and techniques to achieve variable camber mechanism. Variable camber can be achieved span vice or chord wise on an aerofoil where a slight variation in thickness changes lift coefficient. Variable camber wing is a flexible structure that changes its shape profile at different aerodynamic load these types of wings are tested under different load conditions and Reynolds number in wind tunnel facility to have a detailed study on the performance. In this paper an attempt has been made to cover all the shape shifting and morphing wing technologies and compare the results and discuss the possibility of adaption of such technology in aerospace industry.
Review on influence of radiating and aerodynamic shock at hypersonic vehicle
Authors: Balaji R , Muruga Lal Jeyan J V , Singh Vijay Kumar 
Published: March 2020

Abstract
Hypersonic vehicles are going to play a huge role in the upcoming years. As the vehicle has to attain the hypervelocity flow front at the leading edge of the vehicle, need to be strong enough to withstand the effect of the shock wave and radiating waves. Aerodynamic design and the velocity range decide the aerodynamic heating rate of the vehicles. It is known whenever the flow field and the radiation are coupling one another that make the shock layer region complex to analyse. In general inside the developed shock layer, heat flux variation is maximum that enhance the heat transfer. Technically in practice the ability to alter the heat transfer rate of the outer skull depends on the aerodynamically design. To achieve and maintain the hypervelocity region minimizing and or sustaining the aerodynamic heating is necessary. To achieve that regression study on those mentioned three parameter is mandatory. In this review, design and cooling method of different types of hypersonic vehicles taken, and the possible ways to reduce the intensity of shock waves are discussed.
A Critical Review on the Application of Computational Fluid Dynamics in Centrifugal Turbomachines
Authors: Nilugal Manjunath L , Vasudeva Karanth K , Madhwesh N 
Published: March 2020

Abstract
Centrifugal turbomachines are the popular type of power absorbing machines especially used in many industrial applications. In these devices the energy from the rotating impeller is transferred to the fluid to increase its pressure energy. The flow phenomena in these machines is very complex because of the presence of adverse pressure gradients in the flow passages. The level of complexity of turbomachinery flow fields is directly influenced by flow-path geometry and component blade geometry. Hence there is a dire need of advanced flow modelling techniques to understand and capture the fluid characteristics in these flow devices. To design such flow domains, advanced Computational Fluid Dynamics (CFD) tools are required that are capable of accurately modelling the complex flows encountered in turbomachinery applications. These models reflect the full three-dimensional, turbulent, transonic, and often unsteady nature of the actual flows. In addition, they must allow analyses to be performed in reasonable amounts of time that can be accommodated within a typical design cycle. With the development of fast and validated numerical methods, and the continuous improvement in clock speed of computer processors, highly complex problems are now being solved using CFD methods even more economically and quickly. This article focusses the efficacy of CFD tools in turbomachinery applications and various parametric methodologies pertaining to efficiency improvement of turbomachines in detail.
Numerical analysis of micro-channel heat sink using ethylene glycol based nanofluid in case of electronics cooling
Authors: Bhuvad Sushant S , Patel A K , Rajput S P S 
Published: March 2020

Abstract
As size of Integrated circuit is goes on decreasing and number of elements per chip increases, the heat dissipation per unit area of IC increases. Therefore, nanofluid forced convection cooling using an micro-channel heat sink is introduced as new research topic for efficient cooling of IC devices. In this manuscript, ethylene glycol base nanofluid has been studied by using five different oxide nanoparticles including Al2O3, TiO2, CuO, SiO2 and ZnO and varying their concentration from 0 to 10% volume fraction. Single phase model has been considered in simulation analysis using ANSYS Fluent 13.0 software and the results obtained from simulation have been validated with previous experimental and simulation work. Furthermore, several aspects of parameters such as local thermal resistance, pumping power and local heat transfer coefficient are presented in below manuscript. From the result it is analysed that ethylene glycol base nanofluid increases the heat transfer parameters very effectively. Further, as concentration of nanoparticle sis increases the convective heat transfer coefficient and pumping power increases. Also, CuO-EG nanofluid cooled electronics devices more efficiently compared to other nanofluid which are considered in this study.
CFD analysis on the effect of radiation and inlet gas temperature on porous media solar heater
Authors: Warghat Ketan V , Sathish Kumar D , Jayavel S 
Published: March 2020

Abstract
The effect of porosity on flow and thermal characteristics is significant. Fluid flow through porous media has many practical relevance such as agriculture, engineering, bio-medical, etc. applications. In the present study, flow of gas and through solar heater is simulated and the heat transfer characteristics are studied. Two-dimensional numerical simulations are carried using ANSYS-Fluent. Velocity of gas at the inlet is varied from 0.005 to 0.5 m/s and passed through the porous media with porosity value of 0.7. Results are presented in the form of pressure variation, velocity variation and temperature variation.
Energy Management with Bi-Directional Converters in DC Microgrids
Authors: Sreeramulu Mahesh G , Puskar Aman , Murali Krishna P. , Rajashekhar S. 
Published: March 2020

Abstract
The application of Bi-Directional converter has been well notified in Electric Vehicles and the energy flow between the Grid-2-Vehicle and Vehicle-2-Grid are flexible, reliable, efficient and with reduced number of hardware components as compared with conventional DC-DC converters. Using these benefits, the Bi-Directional Converters are used in the DC Microgrids to charge the storage elements in the grid connection mode and to discharge the storage elements in the islanded mode of operation. In this paper, the balanced energy flow between the Storage Elements (Charging Mode) and DC loads (Discharging Mode) using Bi-Directional Converters with Fuzzy control technique is proposed. With this system, the Demand Response objectives like minimization of energy cost and awareness to the social welfare are achieved. The proposed Bi-Directional Converters system is developed using MATLAB-Simulink software and the energy flow between the battery and utility grid or DC load waveforms are shown.
Comparative fatigue life estimations of Marine Propeller by using FSI
Authors: Vijayanandh R , Venkatesan K , Senthil Kumar M , Raj Kumar G , Jagadeeshwaran P. , Raj Kumar R 
Published: March 2020

Abstract
Generally, inward and outward effects are huge and prime in the rotating components. Based on the working environments of a rotor, the complexity is increased furthermore. In this work also deals the same problem, which is fatigue life estimation of marine propeller for different materials under given Ocean environments by using Ansys Fluent 16.2. The conceptual design of the Marine propeller is modelled with the help of CATIA. Fatigue life estimation on the rotor is key and complex output of this work, advanced methodology is mandatory for computation therefore Fluid-Solid Interaction (FSI) technique is used as advanced numerical simulation. Fluid properties such as density and operating pressure are used to define the Ocean environment in the Ansys Fluent 16.2. In the case of structural simulation, the existing materials such as Aluminium alloy and Stainless Steel are used for fatigue life estimation. Finally, the fatigue life estimation of marine propeller is extended for Composite material to compare the life of a rotor.
Circuitry parameter analysis of piezoelectric materials for micro energy harvesting
Authors: Manoj R M , Sudheer Reddy J 
Published: March 2020

Abstract
Energy scavenging using piezoelectric materials is conventional and reliable method of energy harvesting in case of wireless sensor application. The mechanical stress or strain caused on the piezoelectric material leads to generation of voltage which in turn can be used for storage in batteries. This article deals with simulation of circular piezoelectric transducer using COMSOL software and the comparison of various parameters with respect to the structure is studied, also the experiment is conducted to compare the voltage values generated by piezoelectric transducers in different circuitry connections. This data signifies the efficiency and adaptability of piezoelectric transducers for various applications.
Enhancement of Heat Transfer in Perforated Circular Finned-Tube Heat Exchangers: A Numerical Investigation
Authors: Rai Ankur , Bhuvad Sushant S , Sarviya R M 
Published: March 2020

Abstract
The effects of employing perforations of circular shape in circular finned-tube heat exchangers (CFTHEs) are numerically investigated in the present study using Computational Fluid Dynamics (CFD) software. Simulations performed on the validated CFD model shows considerable increase in the Average Nusselt Number for perforated circular finned-tube heat exchangers (PCFTHEs) as compared to their solid counterpart, with only a slight increase in Euler Number for 10,000 ≤ Re ≤ 50,000. Diameter of perforations (dp
) is kept equal to 6mm and optimum range of number of perforations per fin (np
) by analysis is found to be 16 to 20. For this range, the performance of PCFTHEs improves with the increase in number of perforations per fin. The maximum increase in Average Nusselt Number is 24% for dp
= 6mm and np
= 20 at Re = 10,000. The minimum increase in Average Nusselt Number is 3% for dp
= 6mm and np
= 14 at Re = 40,000. This increase in Average Nusselt Number on introducing perforations is due to (i) flow of localized air jets through the perforations, and (ii) reduction in recirculation region caused by the separation of flow. This improvement in the performance of CFTHEs on introducing perforations is achieved with the maximum and minimum reduction in weight of 41% and 29% respectively.
Study of circulation ratio for natural circulation in water-tube boiler at different operating conditions.
Authors: Elgandelwar Atul M , Jha R S , Lele Mandar M 
Published: March 2020

Abstract
The basic objective of the paper is to identify the desired circulation ratio for the natural circulation of water tube boilers in different operating conditions. This requires the basic study of heat flux and the mode of the boiling heat transfer, and the phenomenon like departure from nucleate boiling and tube overheating. The parameters, which need to be studied are heat flux, pressure, dryness fraction, void fraction, liquid velocity and their impact on the required circulation ratio. For a natural circulation boiler, the circulation ratio is one of the most important design parameters as the other design parameter like critical heat flux and skin temperature are mainly derived from the circulation ratio. The required circulation ratio can vary with the boiler pressure, liquid velocity and maximum heat flux. This study is intended to provide input for the safe and optimum design of a natural circulation boiler.
Heat transfer studies for infrared radiation assisted curing in polymer composites
Authors: Uday M , KiranKumar P 
Published: March 2020

Abstract
Conventional materials are replaced by polymer composites in every field due to its wide applications and its ease to custom make the required properties for the purpose it is designated for. Structural applications require higher strength, and this is achieved only by better curing of polymer composites during its processing. Elevated temperature curing helps to improve cross linking of polymers. In this regard infrared radiation curing is one of the methods adopted in the recent days for elevated temperature curing of polymer composites. It is one of the efficient ways of curing polymer matrix composites. In this paper Infrared radiation heat transfer studies of polymer composite is reviewed and compared its efficiency with the hot air or conventional curing method. Further modelling is carried out to prove the efficacy of the same.