Diana Monica Sas

Optimizing the casting length of single diameter steel billets based on minimum cost

The hot rolling process uses, as raw material, round bars casted using continuous casting at the steel making plant. From here a limited number of casted billets, in terms of length, can be delivered. The supply order for the rolling process is unpredictable and imprecise, thus in this scenario the current paper intends to offer a solution to the industrial partner as to optimize the casting lengths of billets, considering the restrictions of the casting process, and to achieve minimum production cost. An order is converted into a number of billets that should be casted at an ideal length. Two different methods are proposed, an analytical one, designed by the authors, and the linear programming method, in order to generate an optimal solution to the stated problem based on minimizing a cost function. The analytical methods result is the optimal number of steel blocks that need to be casted at a single length, from the limited set. The linear programming methods result is the optimal number of blocks that need to be casted from each available length. The results obtained from both methods are compared based on a set of casting orders via successive simulations.

Optimization of the Casting Length of Billets and Computation of Minimum Number of Steel Batches

This paper deals with the optimization of the casted billet’s lengths, in the context of diverse received orders. Linear programming is used in order to solve the optimization problem, such that minimum cost for the optimal lengths results. A technological constraint is that the number of resulted billets for each casted length must be an integer one. The authors also propose an algorithm for determining the number of batches of liquid steel needed to cover all pieces at optimal lengths for the diverse orders, and also the scheduling order of the casting process.

Preliminaries in (Mpdx) method associated with Cohen equations

In this paper is presented a distributed parameter process represented by an isotope separation column for 15N. The method of Matrix of Partial Derivatives of the State Vector Mpdx associated with Taylor Series is presented by including a process modeled by Cohens nonlinear partial differential equations of first order in relation to time t and second order in relation with two independent variables, time and space.

Mathematical model for 18 O isotope separation column operated by product extraction regime

The mathematical modeling of 18O separation column by isotopic exchange between nitric oxides-nitric acid system is presented while extraction is performed from the column. Such a production regime leads to major changes in the equilibrium equations in comparison with the case with total reflux (no extraction). The presented model is useful both to predict the expected production rate and to predict the isotope concentration in the final product.

Mathematical model for 18 O separation column based on chemical exchange between nitric oxides and nitric acid solution operated at total reflux

Isotope separation columns are complex plants, with numerous input and output variables. Accurate but still simple mathematical models are necessary both in analysis and synthesis. The present paper deals with the mathematical model of the 18O separation column based on isotopic exchange between nitric oxides-nitric acid, operated at total reflux. The simulation results proves good accuracy.

Mathematical formalisms used in the orthodontic dynamics

This paper presents an orientation towards the medical engineering of the orthodontic dynamics. Mathematical formalisms, considered most representative, have selected. They are used in the actual detailed study of rather simple orthodontic processes. It is a enumeration of mathematical relations, limited in content and form, with the purpose of highlighting only the representative aspects of the calculation technique. A compromise has been used, for the simplest presentation of both medical phenomena and mathematical details associated to these phenomena. A unitary, synthetic and simple enumeration of the “medical phenomena - calculus technique binomial” was also wanted, as it gradually becomes a highly interest aspect in medicine, in general, and in the orthodontic dynamics, in particular.

Time and space constants in the orthodontic dynamics

Exponential signal categories, usual in the orthodontic dynamics, are considered, damped aperiodic in relation to time and space. They are expressed through time and space constants. For predetermined conditions, expressed in final durations, final lengths and inflexion points, respectively, this paper presents a digital method for determining the structure parameters, by the resolution of two categories of transcendent equations.

Optimization of the Number of Steel Billets that Need to Be Casted in a Charge Using Simplex Method

During the metallurgical process, per each charge, the raw material is continuous casted in order to obtain billets. The main goal of this article is to optimize the number of casted billets per charge using Linear Programming’s algorithm called Simplex. The maximisation of the number of casted billets regard to available lengths and weights has been implemented in Matlab enviroment. Using Simplex Method, the maximum number of casted pieces per charge and the number of billets for each length were achieved in order to obtain good performances, and minimum liquid steel waste.

Preliminaries in numerical simulation of isotope separation closed-loop processes

This paper presents a distributed parameter process, which represents the controlled plant, that is numerically simulated using the method of Matrix of Partial Derivatives of the State Vector Mpdx associated with Taylor Series. The plant is represented by an isotope separation process. Mpdx method with approximate solutions is presented by including a process which is modeled by a partial differential equation of second order with two independent variables. Also, the approximating solutions are needed not only for ensuring the start of the calculations but also for checking the results.

Modeling and Simulation of the Sulfur Dioxide Adsorption Process in Natural Zeolites

The paper presents a solution for modeling and simulation of the adsorption process of the sulfur dioxide in natural zeolites. The adsorption process is modeled as a distributed parameter process, its dynamics depending on three independent variables: time and two spatial variables. In order to simulate the adsorption process, an original form of the approximating analytical solution which describes the process work in dynamical regime is proposed and used. The coefficients of the approximating analytical solution are determined using experimental data obtained from the real plant. A direct practical application, resulted through the simulation of the obtained mathematical model, is the approximation of the time period in which the saturation of the zeolites of different dimensions occurs. Having the mentioned time period, the operators from the industrial field can decide with precision the moment when a zeolite block has to be replaced in order to avoid the environment pollution.