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This paper proposes and solves a mathematical model to predict the behavior of precipitation in the city of Tunja. For this, pluviometric information was subjected to fitting tests to probability distribution functions, finding the Gumbel function as the optimal one. Then, by means of mathematical treatments that use this distribution and applying the multiple linear regression method, the relationship between intensity, duration and frequency of precipitation (IDF) was determined. With the established model, the IDF curves were plotted for different return periods, depending on the duration of the precipitation event. The previous procedure was applied to the data of four stations that affect the basin that crosses the city of Tunja, generating fundamental information for the decision making in the design of engineering works and in the prevention of disasters. [ABSTRACT FROM AUTHOR]

In this paper we show an extended model that describes the dynamic interaction between the immune response of a mammal and Tripanosoma cruzi parasite during the acute phase of a Chagas Disease. The model considers the immune and cellular response, plus the different stages (intracellular and extracellular) of T. cruzi inside of a mammal host. The analysis of the time evolution of populations is made obtaining phase diagrams to determine the stability of the steady states in terms of its parameters. The system gives two steady states, which are associated with the Healing and Chronic state of the disease. The dead case obtained before when only the humoral immune response is considered it gets disappeared. The fundamental implication of this result is the benefit that the cellular immune response produces for the host as for the parasite, since it allows to extend the life of the host, while extending the critical state of the disease without destroying the habitat of the parasite. [ABSTRACT FROM AUTHOR]

Previous scientific research has not focused on downdraught beehive kilns, which are the most used in the Colombian brick (ceramic) industry. Hence, in the present paper, an analytical mathematical model is developed in order to simulate the exhaust gas behavior. To do so, gas combustion and heat and mass transfer to the products and the walls are modelled within the kiln. The obtained model is validated by experimental data. Finally, with the experimental data acquired in the discharge duct and chimney, a heat recovery system is proposed to make use of the residual energy. [ABSTRACT FROM AUTHOR]

The objective of this paper is to model the supply, demand and stock variables of the Colombian green coffee market commercialized as a commodity. Based on these variables, a model of dynamic systems is formulated using ordinary differential equations, which allow observing the behavior of the Colombian coffee market. The analysis takes into account some parameters, such as export and import rates, estimated from historical data on the coffee market reported by official entities. The document shows the formulation of the model, followed by the calculation of the equilibrium points and their stability. Finally, simulation of state variables is presented. [ABSTRACT FROM AUTHOR]

In the present paper necessary elements to obtain a model in order to achieve criticality and complexity for equipment and technological systems in electric power plants are proposed. This kind of model allows the possibility of establish priority orders to care the assets over real basis. Nowadays the classification of assets made in power plants is far away from the required because it is not in correspondence with specific conditions in each place and also is a fact that there is not an effective tool to make it possible. As a result of the work field done, a personalized model for criticality and complexity in electric power plants was obtained. The application of this tool allows obtaining, through a list or a matrix, the calculated and weighted criticality and complexity values. With these values the organization will be able to set maintenance priorities adequately and improve maintenance management significantly. [ABSTRACT FROM AUTHOR]

Nowadays, the basic element to be used in the industry is the PLC, whose main function is to control the systems and processes in the industry. The use of virtual labs in preliminary stages in the complete assembly of the production lines helps to save money and time. It gives the advantage of having controllers and sequential logic mostly working, before having the system completely ready. This paper presents the development and implementation of a virtual environment of a conveyor belt in a brewery. Through the OSC protocol, the virtual laboratory and the PLC can communicate and achieve emulation of the real system in a virtual environment, where the PLC has been programmed as it would be done for an industry. [ABSTRACT FROM AUTHOR]

This paper deals with the mathematical modeling of an all glass evacuated solar collector. It was obtained an equation to evaluate the flow produced by the effect of the solar radiation on the tube.The equation takes into a count the flow area occupied by the hot fluid and the cool fluid besides the tilt angle and ratio length/diameter of the tube of solar collector. [ABSTRACT FROM AUTHOR]

This paper presents a result of research financed with own resources; It presents a state-space model of a three-phase controlled Active Front End rectifier. Using this model, we design a control law oriented voltage (VOC), directed to behavior as resistive load, unity power factor, which is tested by simulation using SimPowerSystem Toolbox in Matlab - Simulink ®. [ABSTRACT FROM AUTHOR]

In this paper, the mathematical modeling and simulation of the automatic control of the quintuple effect of evaporation of a sugar mill "El Palmar" in Venezuela is made. The multiple effect consist of 5 evaporators Robert type, with equal characteristics, connected in series. Starting from the desired operating conditions and control requirements: level in each evaporator vessel, cane syrup concentration and pressure in the fifth evaporator vessel using mass balances, balance on solids for each evaporator and energy to the barometric condenser is present at the output of the fifth vessel, the nonlinear model of the process is obtained, resulting in a system of multiple inputs and multiple outputs, with strong interactions between variables. In the design of the system of the automatic process control, we are interested in maintaining the variables that characterize the performance of it and they are regulated in an operating point; we proceed to linearize the model around an equilibrium point, resulting in a new model in terms of the variables variations around an environment from that point. Then, it is processed the model obtained in terms of input and output relations, based on the characterization of it in terms of variables and transfer relationships in the complex frequency domain. Finally, the evaporation process is simulated, establishing the adequacy of the model to the real process. [ABSTRACT FROM AUTHOR]

This paper presents a new multiobjetive mathematical model for optimization of facility layout problem with unequal areas called UA-FLP with fixed dimensions. One of the objectives is the minimization of the material handling cost and the other one is the minimization of the closeness relationships according to factors that are independents of the flows and costs. The validation of the mathematical model was made with problems found in the literature. The result was that the proposed model represents the unequal area facility layout problem with fixed dimensions optimizing the material handling cost and the closeness relationships for small problems and finding good solutions for bigger problems in 10,000 seconds of computer time. [ABSTRACT FROM AUTHOR]

In this paper the basic structure and design of a torque controller for an electric vehicle driven by induction motor is presented. The basic structure of the electric vehicle in question and its mathematical model is presented first. After that, the operation principle of the conventional direct torque control is analyzed and from this a new controller with fixed constant switching frequency is designed. To generate the switching pulses sine PWM is used instead of the hysteresis comparator and switching table commonly used in direct torque control. Finally, simulation comparison was performed. This shows that better performance was achieved with the proposed controller with lower torque and flux errors, and lower torque and stator current ripple. [ABSTRACT FROM AUTHOR]

In this paper, we study a numerical approximation Free Boundary Problem (FBP) of a system of differential equations of nonlinear one-dimensional parabolic type, associated with the evolution of the interface, which describes the regional partition of two groups of individuals in a same species interacting in a spatial limit to obtain their own habitat and that is a priori completely unknown. Taking into account the local dynamic of the system, the implicit finite difference scheme is used, obtaining a nonlinear algebraic system of equations in each time step. Finally, some simulations of the distribution of population density and the evolution of the free boundary are displayed according to the time in different scenarios, based on an algorithm proposed and implemented in MATLAB, this validates the mathematical model FBP. [ABSTRACT FROM AUTHOR]

This paper presents the model of a virtual drive system of an underwater mobile platform inspired by biomimicry, selecting the subcarangiform mode of fishes as locomotion system which is based on body and caudal fins (BCF). This model uses two-thirds of the body for thrust and one of the most important features is the high maneuverability. The development of the model is based on simulation by designing the 3D model of the prototype using a computer aided design software (CAD), an analysis by considering the direct and inverse kinematics and a navigation control system by implementing the fuzzy logic. The algorithm implemented to solve the inverse kinematics is based on geometric methods considering the workspace and dividing it into subareas in order to analyze position, velocity, acceleration and torque for every joint of the robot fish. Also, a navigation control algorithm was developed using the fuzzy logic as non-linear control method. The results represent an approximation of subacarangiform mode offish behaviours for future physical implementation of an underwater platform inspired by biomimicry. [ABSTRACT FROM AUTHOR]