Papers by Madalina Calbureanu
In this paper we present the analysis of convective heat transfer in the walls of a house insulat... more In this paper we present the analysis of convective heat transfer in the walls of a house insulated with polystyrene. In the first part we make an evaluation of the insulation that is currently used in the houses. We start the simulation using a real model of a house and than we make the model in Solidworks 2009. We run the model in Solidworks Thermal study after we insert the initial conditions. We notice that the obtained results indicate a problem which occurs inside the brick, the dew-point appearance. Further investigations must be made to solve this problem. Keywords— convective heat transfer, dew-point, finite element, polystyrene insulation, thermal bridges.
International Review of Civil Engineering, 2013
This scientific paper reveals the main characteristics of Oltenia Region in order to evaluate the... more This scientific paper reveals the main characteristics of Oltenia Region in order to evaluate the seismicity of this important zone from Romania South West Region. There are presented the geomorphological map and also the vulnerability map of this region and the damages after the strongest earthquake from Vrancea source (Romania) on the 4th of March 1977 (MW=7.4). These damages are presented in dynamic conditions of that massive seismic event. The results interpretation and conclusions are done in the context of the real response of the buildings from the territory of Oltenia Region
IOP Conference Series: Materials Science and Engineering
In this study the physico-chemistry characterization and the thermal behaviour of biodiesel and d... more In this study the physico-chemistry characterization and the thermal behaviour of biodiesel and diesel fuel were carried out. Biodiesel is currently the most suitable fuel as alternative for diesel engines due to the environmental and technical advantages. In Romania the use of blends of biodiesel/diesel as fuels is growing every year mainly to the implementation of Kyoto protocol and to the similar properties to diesel fuel. The tests were realized under atmospheric conditions of pure air flow at various heating rates. The thermogravimetric profile indicates that diesel has three mass losses events and biodiesel of sunflower oil has five mass loss events.
E3S Web of Conferences
Biofuels are considered to be attractive alternative fuels due to rising oil prices and the deple... more Biofuels are considered to be attractive alternative fuels due to rising oil prices and the depletion of fossil sources. It is produced by a process of transesterification of vegetable oils and animal fats with an alcohol in the presence of a catalyst. At present, biodiesel and bioethanol are considered solutions, and almost all EU countries have prepared a policy on the production and use of biodiesel in the transport and heating sectors. Biodiesel has certain advantages, such as a higher number of cetan, biodegradability, low sulfur content and aromatic content, and lower carbon monoxide emissions, unburned hydrocarbons and particulate matter. One of the main issues related to biodiesel and biodiesel blends is the high viscosity of the fuel. Among the biodiesel properties, density, viscosity and heating value affect engine performance and emission characteristics. The presented paper highlights the differences that occur in comparison to the classical fuels and the performances ob...
In this paper one presents an algorithm for project of a reduced order observer (ALGLOOR) with ap... more In this paper one presents an algorithm for project of a reduced order observer (ALGLOOR) with applications to flying objects' move. The command law is an optimal one in rapport with state vector of the observer. Numeric calculus examples are also presented: for longitudinal and lateral move and vertical move of a rocket in vertical plane in rapport with equal
This monograph used in experimental investigations a crank and connecting rod mechanism with one ... more This monograph used in experimental investigations a crank and connecting rod mechanism with one of the kinematic links made of different materials. The longest link was made of linear viscoelastic material in the first part of the study and the stress and strains were highlighted; the influence of the behavior of this particular type of material above the vibrations of the kinematic element was studied. The second part of the study used a deformable elastic material for the longest link. Moreover this link was subjected to the pressure of the oil from a rectilinear pair during the motion of the mechanism. There were used in experimental investigations different types of oils as lubricants of the rectilinear pair and the vibrations of the elastic kinematic element were studied.
This paper presents the modal analysis for different kinds of buildings having symmetry around Y-... more This paper presents the modal analysis for different kinds of buildings having symmetry around Y-axis. This study includes the dynamic behavior of buildings considered as elastic constrained rigid subjected to seismic actions. The results are interpreted for two different kinds of buildings-one with symmetry around X-axis and another one non-symmetric.
Advanced Engineering Forum, 2018
Active House is a vision on some buildings that create a healthy and comfortable life for their o... more Active House is a vision on some buildings that create a healthy and comfortable life for their occupants without influencing in a negative way the climate and environment - leading to a cleaner, healthier and safer world. Active House proposes a target framework for changing the way we build and renovate buildings in order to contribute positively to our health, safety and well-being, focusing on indoor and outdoor environment and on the effective use of energy.
Abstract:- The paper presents a new algorithm for optimal control law’s synthesis in rapport with... more Abstract:- The paper presents a new algorithm for optimal control law’s synthesis in rapport with state vector of the aircraft’s move. Starting from state equation of the movement, the system is brought to Jordan canonic form and Riccati algebraic matricidal equation (whose solution is the gain matrix of the control law) is brought to an equivalent form with transformation relation. The new gain matrix is partitioned conform to equations (35) ÷ (40). Using ALGLX algorithm, one studies elastic no deformed (no dimensional description) longitudinal and lateral move of an aircraft and dimensional elastic deformed move. One obtained Matlab/Simulink models and numerical programs and with them time characteristics expressing state variables’ dynamic are obtained. Key-Words:- algorithm, optimal, control law, longitudinal and lateral move, synthesis. 1
IOP Conference Series: Earth and Environmental Science
The paper presents the analysis of water and heat transfer through walls being thermally insulate... more The paper presents the analysis of water and heat transfer through walls being thermally insulated with vegetal materials. The analysis identifies the risk for condense accumulation in the outer layers of external walls of a common residential building located in the coldest climatic regions of Romania. Different wall structures and insulation thicknesses are systematically considered with statistical extreme temperature and humidity outdoor values. Results are useful in designing nZEB individual houses with green and sustainable technologies that also provide energy savings and indoor conditions for good comfort and health in these desired building concept.
The exhaust pollution has become one of the important problems of environment pollution with appl... more The exhaust pollution has become one of the important problems of environment pollution with applications in automobile industry, and the exhausted muffler has been paid attention to improve the performance of engines. Computational Fluid Dynamics (CFD) method was used to explore the aerodynamic performance of the muffler. The dimensions of muffler design should be limited in the demand of assembly with simple structure. Resistance muffler research relates with the fields of acoustics, fluid dynamics, heat transfer and mechanism design. The author simulated the field by numerical method with Cosmos Flow and analyzed the effect which the internal flow field has on the performance of the muffler, which may be a credible guidance of the muffler structural design. With this method the pressure distribution in the muffler is simulated and the pressure loss is predicted for the structure modification. The experiment results verify that the assembly performance of the muffler modified is better than the original muffler.
In this paper we achieved a nonlinear analysis of a piston head from a spark ignition engine in d... more In this paper we achieved a nonlinear analysis of a piston head from a spark ignition engine in different working condition. The heat transfer in the combustion chamber of an internal gasoline engine was determined mainly as a function of the parts temperature and combustion temperature. As initial condition we considered a temperature on the head piston of 330 0 C and a total pressure of 5 MPa. The simulation gave us information about the heat transfer in the piston head and the piston material loading. Key-Words: piston head, heat transfer, model, engine, temperature field, pressure.
The paper presents a method for dynamic analysis of mechanisms where the kinematic elements were ... more The paper presents a method for dynamic analysis of mechanisms where the kinematic elements were considered deformable solids. The method was tested on a four-bar mechanism. The elastodinamic analysis was possible by coupling the motion as solid rigid body and the motion as deformable solid considering the links as finite elements. The equations of motion are decoupled by taking into account static and dynamic components for nodal forces matrix, stiffness matrix and damping matrix. The motion equations solving was possible by taking proper kinematic and geometric constraints imposed by the connections between the kinematic elements. The dynamic modeling is accomplished by developing a finite element formulation. The results of a numerical processing of mathematical models developed for a four-bar mechanism are presented in the second part of the paper. Understanding and controlling structural elastodynamic response are of great importance, due to their practical applications, especi...
For long linear elastic links of mechanisms subjected to vibration, the determination of displace... more For long linear elastic links of mechanisms subjected to vibration, the determination of displacements fields depending on the motion kinematic parameters makes possible the calculus of additional strains tensor components and then the calculus of the additional stress tensor components. The paper presents the calculus of the components of these two additional tensors that occur due to vibration for a specific mechanism, a crank and connecting rod assembly, in precise work conditions. The data are very significant in mechanisms links rigorous designing and dimensioning.
mechanism, elastic displacement Abstract—This paper has as main purpose to identify the dynamic c... more mechanism, elastic displacement Abstract—This paper has as main purpose to identify the dynamic components of the matrices in the motion equation, combining the motion of rigid body with the one of elastic body. The finite element modeling requires the identification of a proper procedure in order to establish accurate boundary conditions which assure continuous motion in the nodes. Finally, an application on a plane mechanism, a four-bar linkage, with theoretical results for the mathematical models validation is presented. These models are useful for the optimization of robot design and to implement active vibration control for real-time applications.
In this paper one presents on virtual models of bones the cinematic and dynamic analysis of the h... more In this paper one presents on virtual models of bones the cinematic and dynamic analysis of the human elbow with the analysis of finite elements. The model is made in Solidworks then is imported in Visual Nastran for the analysis. Then we study the cinematic and dynamic simulation of the bio-system elbow articulation for the movement of deflection-extension with the presentation of different graphics of the ulna. It is studied also for the humerus bone the tension and stress between intervals of 0.1 0, 2 seconds. The results showed that the virtual bone has a great capability to predict the moments of fracture apparition with application to future researches. Keywords— Bio-system fracture, flexion-extension, human elbow, tension. I. THE METHOD DESCRIPTION To obtain the bone cross sections were used a PHILIPS AURA CT tomography installed in the Emergency Hospital from Craiova (Figure 1). Fig.1 The PHILIPS AURA CT tomography Manuscript received April 10, 2010. R. Lungu is with the Uni...
Computer aided engineering (CAE) tools allow engineers to design product and to simulate these de... more Computer aided engineering (CAE) tools allow engineers to design product and to simulate these designs for residual stress, structural response, thermal effects, pre-processing and post processing fatigue on the automotive component. The main purpose of the preliminary analyses presented in the paper was to compare the behavior of the combustion engine piston made of aluminum alloys. The paper describes the mesh optimization with using finite element analysis technique to predict the higher stress and critical region on the component. As initial condition we considered a temperature on the head piston of 330°C and a total pressure of 5 MPa. There were studied two cases, a piston head and a piston, pin and connecting rod.
WSEAS Transactions on …, 2008
The paper presents a new algorithm for optimal control law's synthesis in rapport with state vect... more The paper presents a new algorithm for optimal control law's synthesis in rapport with state vector of the aircraft's move. Starting from state equation of the movement, the system is brought to Jordan canonic form and Riccati algebraic matricidal equation (whose solution is the gain matrix of the control law) is brought to an equivalent form with transformation relation. The new gain matrix is partitioned conform to equations (35) ÷ (40). Using ALGLX algorithm, one studies elastic no deformed (no dimensional description) longitudinal and lateral move of an aircraft and dimensional elastic deformed move. One obtained Matlab/Simulink models and numerical programs and with them time characteristics expressing state variables' dynamic are obtained.
This paper presents an algorithm for identification of the longitudinal and lateral movements of ... more This paper presents an algorithm for identification of the longitudinal and lateral movements of an aircraft. For identification a reduced order observer has been projected. With the obtained reduced order observer a stabilization compensator has been made. To perform the identification, the authors use the Matlab program from Appendix and an algorithm for the feedback gain matrix obtaining (ALGLX algorithm). The obtained results show that the algorithm may be used with good results to any system's identification.
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Papers by Madalina Calbureanu