Verification of a Model as a Scientific Tool of Operations Research : a Methodological Approach

The aim of the research presented in this paper was to solve one of the fundamental problems of modelling and simulation, i.e., verification of a model as a scientific tool of operations research. To attack this problem, certain crucial issues in the philosophy of science (the demarcation problem, the principle of verifiability) must be redefined. In discussing the question of verification, a procedure (the so called RAD-VER procedure) for verifying a model of a microeconomic system, in our case - a firm, is formulated. It is assumed that verification is a ceaseless process of evaluating a model's scientificity from the standpoints of deductive reasoning, coherency and empiricism. Verification has been divided into two stages: the verification of the assumptions underlying the model of a firm and the verification of the simulator. (original abstract

Construction of a flexible simulation model of a corporation

The instability of the real structure of a firm is one of the fundamental problems in simulating microeconomic systems. This paper proposes a method, called ACV (abstraction – gradual concretization – verification) for constructing a flexible simulation model of a corporation. This method is based on the assumption that an effective approach to simulating a microeconomic system should take into account the structural instability of the modelled object. Practical implementation of the ACV method is illustrated using the EK_AN simulator of a firm. The purpose of the simulator as a scientific tool of operations research is to analyse the relations of given inputs (decisions) with the short- and mediumterm forecasts of a firm’s economic performance

Comparative Study on Enzyme Immobilization Using Natural Hydrogel Matrices—Experimental Studies Supported by Molecular Models Analysis

Currently, great attention is focused on conducting manufacture processes using clean and eco-friendly technologies. This research trend also relates to the production of immobilized biocatalysts of industrial importance using matrices and methods that fulfill specified operational and environmental requirements. For that reason, hydrogels of natural origin and the entrapment method become increasingly popular in terms of enzyme immobilization. The presented work is the comparative research on invertase immobilization using two natural hydrogel matrices—alginate and gelatin. During the study, we provided the molecular insight into the structural characteristics of both materials regarding their applicability as effective enzyme carriers. In order to confirm our predictions of using these hydrogels for invertase immobilization, we performed the typical experimental studies. In this case, the appropriate conditions of enzyme entrapment were selected for both types of carrier. Next, the characterization of received invertase preparations was made. As a final experimental result, the gelatin-based hydrogel was selected as an effective carrier for invertase immobilization. Hereby, using mild conditions and a pro-ecological, biodegradable matrix, it was possible to obtain very stable and reactive biocatalyst. The choice of gelatin-immobilized invertase preparation was compatible with our predictions based on the molecular models of hydrogel matrices and enzyme used

Understanding continuous wave laser-induced chemical reactions at micro- and nano-diamond-glass interface under infrared excitation

This work addresses the issue of laser-induced white light generation by nano- and micro-diamond powder and the accompanying redox processes occurring at the surface of the particles. The broadband white light is generated by near infra-red continuous wave laser (975 nm) on micro and nano-diamond powders sealed in lightbulb-like devices. It is shown that the emission from diamond samples is a highly nonlinear process with apparent saturation close to 1 W of the optical excitation power. Multiband mechanism and mixed hybridization at particle surface are further discussed as a possible origin of the white light emission. Changes in the sp ^2 /sp ^3 ratio upon the laser excitation are here discussed in terms of molecular dynamics simulations. Observed surface changes related to diamond graphitization are considered further as possible pathways for chemical reactions at the interface of the glass and diamond samples. Obtained results bring relevant physical premises according to the possible mechanism responsible for the white emission from diamond-like carbon materials, its mechanisms, and an essential figure of merit considering the diverse applicability of this phenomenon in various electronic devices