bluuebunny/crossref_metadata_2025_split huggingface dataset:
Experimental Study of Solar Still With Energy Storage Materials
Authors: Reddy K. Vijaya Kumar , Somanchi Naga Sarada , Banoth Hima Bindu , Gugulothu Ravi 
Published: October 2014

In recent years with the exacerbation of energy shortage around the world and the continuous increase in the level of greenhouse gas emissions, the use of various sources of renewable energy is increasingly becoming important for sustainable development.
Solar energy is considered to be one of the most promising sources of energy, owing to its clean and renewable characteristics. Thermal energy storage (TES) is used to assist in the effective utilization of thermal energy in wide number of industrial and domestic applications. Thermal energy is stored as sensible heat (SHS) or latent heat (LHS). Sensible heat storage (SHS) materials are combination of materials (both solids and liquids) which undergo no phase change in the defined temperature range of the storage process. Example concrete, cast steel, cast iron etc.
The use of a latent heat storage system (LHS) using phase change materials (PCMs) is an effective way of storing thermal energy and has the advantages of high energy storage density, narrow operating temperature range and the isothermal nature of the storage process. The phase change materials are more energy dense than sensible energy storage when the temperature difference between heat source and sink are low. Phase change material can store or release energy through its morphology change mechanism. These advantages lead to small volume and less heat loss, which attract attention of researchers in different fields. Ex: Sodium acetate trihydrate, NaNO3.
There are large numbers of PCMs that melt and solidify at a wide range of temperatures, making them attractive in a number of applications. PCMs have been widely used in latent heat thermal storage systems for heat pumps, solar engineering and spacecraft thermal control applications. The uses of PCMs for heating and cooling applications for buildings have been investigated within the past decade.
The experimental results computed in the field of water distillation process using solar energy in the presence of energy storage materials are discussed in this paper.
Modelling and Simulation of Regenerators With Complex Flow Arrangements for Active Magnetocaloric Refrigeration
Authors: Lei Tian , Nielsen Kaspar K. , Engelbrecht Kurt 
Published: October 2014

Compared to a conventional vapor compression refrigeration system, a magnetocaloric refrigerator has many advantages, such as potentially high efficiency, low vibration and avoidance of refrigerants that deplete the ozone layer and cause the greenhouse effect. As a main component of the active magnetic regenerative refrigerator, the regenerator plays an important role in the cooling performance and efficiency of the whole system. However, the regenerator design is constrained by several external factors, such as the geometry of the magnetic field source and flow resistance.
In this work, novel regenerators with complex flow arrangements, providing high performance at lower pressure drop, are investigated. Correspondingly a one dimensional model is presented and comparative studies between novel and conventional regenerators are carried out by simulation. The effect of regenerator geometries and different flow arrangements on the cooling performance, pressure drop and efficiency are investigated. In particular, the effect of so-called dead volume on the performance of a regenerator is researched.
Drive System Sizing of a 6-DOF Parallel Robotic Platform
Authors: Giberti Hermes , Ferrari Davide 
Published: October 2014

In this work, it is considered a 6-DoF robotic device intended to be applied for hardware-in-the-loop (HIL) motion simulation with wind tunnel models. The requirements have led to a 6-PUS parallel robot whose linkages consist of six closed-loop kinematic chains, connecting the fixed base to the mobile platform with the same sequence of joints: actuated Prism (P), Universal (U), and Spherical (S).
As is common for parallel kinematic manipulators (PKMs), the actual performances of the robot depend greatly on its dimensions. Therefore, a kinematic synthesis has been performed and several Pareto-optimal solutions have been obtained through a multi-objective optimization of the machine geometric parameters, using a genetic algorithm.
In this paper, the inverse dynamic analysis of the robot is presented. Then, the results are used for the mechanical sizing of the drive system, comparing belt- to screw-driven units and selecting the motor-reducer groups. Finally, the best compromise Pareto-optimal solution is definitely chosen.
Vibration Analysis of a Vertical Roller Mill: Modeling and Validation
Authors: Çopur Engin H. , Salamci Metin U. , Gülbeyaz Selahattin 
Published: October 2014

In this paper, vibration characteristics of a Vertical Roller Mill (VRM) are studied by using physical parameters of an operating VRM. The mathematical model is derived and simulated for a set of working parameters. Mechanical properties of the grinding material and the physical properties of the mechanical construction are used in the vibration model in order to obtain more realistic results. Simulation results are presented which give critical frequencies of the VRM. The effects of the hydraulic compressive force to the vibration characteristics are investigated. The effects of the material feeding rate (which affects the mineral thickness to be grinded) to the vibration characteristics are also simulated.
In order to validate the mathematical model, a set of experimental vibration tests are performed on the VRM. Vibrations are measured during the run-down procedure of the VRM in order to determine natural frequencies of the mill as well as excitation frequencies of the system. The measurements showed the validity of the proposed mathematical model for the vibration analysis of the VRM.
Thermo-Economic Analysis of a Solar Heating and Cooling System With Desiccant-Based Air Handling Unit by Means of Dynamic Simulations
Authors: Angrisani Giovanni , Roselli Carlo , Sasso Maurizio , Tariello Francesco 
Published: October 2014

Solar Heating and Cooling systems are a virtuous alternative to conventional air conditioning plants, as a renewable energy source (solar energy) is exploited.
In this paper the coupling of low temperature solar devices with an innovative desiccant-based air handling unit, which meets the sensible and latent loads of a simulated lecture room, is analyzed through TRNSYS dynamic simulation software. The components have been characterized by means of experimental tests carried out at the test facility of Università degli Studi del Sannio. The desiccant-based air handling unit current set-up allows summer operation only. However, heating operation is also simulated, as comfort conditions can be maintained in the conditioned space exploiting solar thermal energy also in winter, with some modifications to the air handling unit. A parametric analysis is performed to compare different technical solutions (collector types, surface, tilt angle) and to identify the optimal one, taking into account energy, economic and environmental performance with respect to a reference system.
The best case in terms of energy and environmental performance is represented by evacuated collectors, achieving a primary energy saving of 64% and a CO2 emissions reduction of 61%; flat-plate collectors are instead the best solution in terms of pay-back period (6 years).
Configuration Design and Energy Balancing of Compact-Hybrid Powertrains
Authors: Walker Paul D. , Roser Holger M. 
Published: October 2014

The development of compact and efficient hybrid electric vehicle powertrains for low initial and on-going costs requires consideration of numerous, often competing factors. Appropriately designing and sizing these powertrains requires the consideration of requirements for vehicle range and performance, considered directly through the sizing of motors and engines, and indirectly through minimization of vehicle mass whilst being constrained by total stored energy in the vehicle, against the impact on vehicle emissions and on purchase and ongoing operational costs. In addition to these considerations the actual driver use will strongly influence the energy consumed and vehicle emissions. It therefore becomes beneficial to provide flexibility in hybrid vehicle configuration design to enable the minimization of vehicle emissions and ongoing vehicle costs.
The purpose of this paper is to study the various alternative vehicle powertrain configurations for application to small scale hybridization demands, such as scooters or motorcycles. Powertrain configurations studied in this paper include plug-in hybrid electric (PHEV), battery hybrid electric (BHEV), and a pure electric vehicle (PEV). To design and size each of the configurations a statistical approach is taken, power and load demands are studied and utilized to size powertrain components. Results are extended to size vehicle energy storage for electric only range of 25, 50 and 100 km, and total vehicle range of 100 km for the BHEV and 200 km for the PHEV. Based on the results developed from the analysis mathematical models of each of the powertrain configurations are then developed in Matlab/Simulink and numerical studies of vehicle energy consumption in comparison to range are conducted. Outcomes of these simulations are compared to an operating cost based analysis of the suggested powertrains; the benefits and limitations of each design are considered in detail.
Mechanical Property and Microstructural Characterization of AISI 304L: Application Spot Welding
Authors: Sidhoum Zehra , Ferhoum Rabah , Almansba Madjid 
Published: October 2014

In recent years, the development of high-strength steels such as multi-phase TRIP (transformation-induced plasticity)-aided steels have shown great promise due to their excellent combination of high strength and ductility. In this paper, the effect of strain-induced martensitic transformation on mechanical properties is studied. Uniaxiale tension tests at different strain rate (10, 15 and 20 mm / min) are conducted at 25° C in order to characterize the mechanical behavior of AISI 304L. The microstructure, particularly retained austenite, is analyzed using optical microscopy, Vickers hardness measurements. The results showed that all properties measured are increased from (Re=390.96MPa to Re=425.96MPa and Hv=300.94Hv to 343.51HV).
Secondly, the influence of the annealing treatment on microstructure and mechanical properties of the joint formed by the spot welding are characterized using tensile test, metallographic analysis and Vickers hardness measurements.
Numerical Simulation of Convective-Radiative Heat Transfer in a Solar Chimney
Authors: Buonomo Bernardo , Manca Oronzio , Nardini Sergio , Tartaglione Gianluca 
Published: October 2014

Solar chimney is a new method to produce electrical power. It employs solar radiation to raise the temperature of the air and the buoyancy of warm air to accelerate the air stream flowing through the system. By converting thermal energy into the kinetic energy of air movement, solar chimneys have a number of different applications such as ventilation, passive solar heating and cooling of buildings, solar-energy drying, and power generation. Moreover, it can be employed as an energy conversion system from solar to mechanical. A component, such as a turbine or piezoelectric component, set in the path of the air current, converts the kinetic energy of the flowing air into electricity.
In this paper, a numerical investigation on a prototypal solar chimney system integrated in a south facade of a building is presented. The chimney is 4.0 m high, 1.5 m wide whereas the thickness is 0.20 m for the vertical parallel walls configuration and at the inlet 0.34 m and at the outlet 0.20 m for convergent configuration. The chimney consists of a converging channel with one vertical wall and one inclined of 2°. The analysis is carried out on a three-dimensional model in airflow and the governing equations are given in terms of k-ε turbulence model. The problem is solved by means of the commercial code Ansys-Fluent. The numerical analysis was intended to examine the effect of the solar chimney’s height and spacing. Further, comparison between radiative and non-radiative model is examined and discussed. Results are given in terms of wall temperature distributions, air velocity and temperature fields and transversal profiles for a uniform wall heat flux on the vertical wall equal to 300 W/m2. Thermal and fluid dynamics behaviors are evaluated in order to have some indications to improve the energy efficiency of the system.
Assessment of Turbocharger Turbine Unsteady Flow Modelling Methodology on Engine Performance
Authors: Mustafa Ammar , Martinez-Botas Ricardo F. , Pesiridis Apostolos , Chiong Meng Soon , Rajoo Srithar 
Published: October 2014

Although it is well known that the flow entering a turbine of a turbocharger engine is highly unsteady, engine manufacturers prefer to use turbine performance predictions that are based on steady-state performance maps, which inherently lead to inaccuracies in the turbine’s behavior and mismatches between turbocharger turbines and engines. The reason for this preference is due to the turbocharger turbine design software that are generally available to engine manufacturers being based on and compatible with steady-state performance maps and this fact led researchers to investigate how the inaccuracies of this steady-state treatment of the turbine can be alleviated.
To this effect, this paper investigates how modelling techniques on Ricardo Wave, a 1D gas dynamics engine simulation software, gives rise to more accurate turbine swallowing curve predictions using steady-state maps. In particular, the turbine being investigated is that of Szymko [1], which is a twin nozzleless mixed-flow turbine that is being powered by a 10 litre, 6 cylinder 4 stroke diesel engine with an operating range from 800–2000 RPM for which 800, 1200 and 1600 engine RPM relate to 40, 60 and 80Hz exhaust gas pulse frequencies at the turbine.
The main investigation in this paper is to demonstrate the capability of the engine simulation software to deal with unsteady flows and specifically to show the significant effect of accounting for the volute design in the single turbine wheel entry model. The data obtained in this investigation were compared with those of Szymko [1], which offered a validated set of data to compare against.
Influence of Real Car Longitudinal Acceleration Regime on the Vertical Vibrations of a Dynamic Car Simulator
Authors: Dumitriu Dan N. , Brişan Cornel , Munteanu Ligia 
Published: October 2014

For dynamic car simulators, it is obvious that the longitudinal motion cannot be fully reproduced, the possibility to simulate longitudinal motions being generally reduced to less than 1m. In our case, a four post shaker is intended to be built as dynamic car simulator. Each post shaker, one under each car wheel, is aimed to generate mainly vertical vibrations and lateral motion. Since the displacements/motion in the longitudinal direction can only be partially reproduced, our problem was how to compensate the impossibility of fully reproducing the longitudinal motion by at least taking into account the influence of the longitudinal motion on the vertical vibrations.
In this paper a simplified 4 DOF “bicycle” model is used for vertical dynamics, instead of a 7 DOF full car vertical dynamics model, which will be considered in a further study.
On the other hand, the vertical vibrations are different for the same car riding on the same road, but for different acceleration regimes: 1) null acceleration (e.g., 60km/h constant speed); 2) uniform acceleration from 10 to 110 km/h (during 8 seconds), followed by uniform deceleration from 110 to 10 km/h (during another 8 sec), then uniform acceleration from 10 to 60 km/h (during the last 4 sec of the simulation).
In order to reproduce in the dynamic car simulator the vertical vibrations of the above-mentioned longitudinal motion regimes (involving displacements of tens of meters), the following steps are proposed: a) direct dynamics CARSIM computer simulations of the car motion and its interaction with the road; b) inverse dynamics of car vertical model (4 degrees of freedom), using as input the following parameters computed in step a): the vertical displacements and velocities of the sprung mass and of the front and rear wheel centers as well as the pitch angle of the sprung mass and its rate. These inverse dynamics computer simulations are performed using an in-house Matlab software programming only the 4-DOF vertical car/road interaction (2D “bicycle” model in the pitch plane, no roll motion considered), without considering any longitudinal motion.
The output of these inverse dynamics computer simulations, using the in-house Matlab software, is the “modified/distorted road profile”. Thus, the modifications brought to the real road profile are aimed to compensate the lack of the longitudinal degree of freedom in the dynamic car simulator, in order to reproduce the vertical vibrations of the above-mentioned longitudinal motion regimes (so that to encounter the same car vertical displacements and accelerations for the in-house Matlab simulation, as for the CARSIM simulation).
Results are presented in order to show how the real road profile is modified/distorted in order to cope with this impossibility to simulate the road profile in dynamic car simulators, without huge costs.
Numerical Algorithm for Non-Stationary Covariance Analysis of Nonlinear Mechanical System Using Equivalent Stochastic Linearization
Authors: Marano Giuseppe Carlo , Acciani Giuseppe , Abrescia Angelamaria 
Published: October 2014

A quite important topic of structural dynamics is deterministic mechanical systems subjected to stochastic dynamic actions, such as for wind or earthquake. IN such cases structural response have to be properly evaluated by a stochastic approach. Unfortunately for nonlinear mechanical systems only in a very few cases exact solutions are available, and usually simply approximate solutions should be used. A well known one is stochastic equivalent linearization, easy and simple from the conceptual point of view. Moreover it needs of specific numerical techniques to be properly implemented, whose complexity increases in case of non stationary conditions.
In this paper a procedure to solve covariance analysis of stochastic linearized systems in case of non stationary excitation is proposed. The no stationary Lyapunov differential matrix covariance equation for the linearized system is solved by using a numerical algorithm that updates linearized system matrix coefficients step by step. This by a predictor-corrector procedure applied to a Euler-implicit integration scheme for the matrix covariance analysis.
It is described in details to be simpler implemented by other researchers, and then applied to a typical and important applicative case, that is seismic response of a Bouc Wen Single Degree of Freedom (SDoF) system. Seismic input processes is modeled as linear filtered white noise non stationary separable process. Accuracy and computational costs are analyzed showing the efficiency of the proposed integrating procedure.
Experimental Analysis of the Transition Between Veering and Crossing on a Two-Beam System
Authors: Giannini Oliviero , Sestieri Aldo 
Published: October 2014

When there is a parameter varying in a system, so that one natural frequency approaches another one, the phenomenon of veering is generally found and highly coupled modes are the emerging characteristic of this dynamic behavior. It is far more difficult to find systems that instead of a veering present crossing between modes, and the crossing phenomenon is almost unreported in the scientific literature, unless the case of uncoupled modes is considered.
In this paper, the two-modes interaction is presented. In particular, mode veering and mode crossing are introduced and investigated through a simple analytic 2-dof model that allows for closed-form solution. Then, an experimental setup, appropriately designed to study the two-modes veering and crossing is presented and experimental evidences of both phenomena are measured showing the main characteristics of such modal interaction..
Applying Actual Development Progress Into Education
Authors: Albrecht Katharina , Anderl Reiner 
Published: October 2014

Todays’ product development process is characterized by an increasing use of embedded software solutions integrated into mechatronic products. The development is more and more translocated into a virtual environment. New software methods and tools have to be developed.
Industry 4.0 is an approach to highlight the tendency of modern development. Communication between smart products, communication via internet technologies, cyber-physical systems and the Internet of Things are the basis of Industry 4.0. Owing this development, used project management methodologies have to be adjusted. In special the well-known V-Model is now extended to the W-Model to cope with the new requirements like communications between different disciplines. New approaches in virtual development have to be adapted to modern teaching techniques. Therefore a course for first semester mechanical engineering students is conducted by the department of Computer Integrated Design at the Technische Universität Darmstadt. Industry 4.0 fundamentals are taught as well as the development process underlying the so called W-Model. The students will apply this knowledge while they participate in exercises. A web-based tutorial is provided every week with different learning packages. With these learning packages, the students learn to use the project management techniques as well as software development techniques to solve different tasks. Later complex data structures and algorithms can be coded and are applied. The software development techniques, established in development of information technologies, gets more important in mechanical engineering. Therefore the students learn these aspects. Over three months length the students work in groups and use all their skills to realize a bigger software-project — a digital factory. They use a virtual testing environment (ViTMeS 3.0) to develop their solution. The presented ViTMeS 3.0 is a further development of a virtual testing environment used in last year’s team work. Later they can test their code with a real life example. This example, the digital factory, built with LEGO Mindstorms, is an important part of teaching students the foundations of communication and information techniques as well as software development and programming skills. The last step of the team work is the coding of a graphical user interface for appropriate visualization.