Importance of data acquisition in problem based learning

This research paper demonstrates untraditional learning and teaching method that is developed from combination of experimentation, usage of computer simulations and problem based learning. Taking all previously mentioned methods together there can be created very successful learning environment which provides students to master electromagnetism more effectively. Research focuses on proper use of data acquisition modules and computer simulations in PBL teaching method. Based on the results of the research experimental PBL in various cases provides better learning outcomes, but there are also a few occasions where the results aren’t so pleasing. Overall PBL provides results that are at least as promising as results of other teaching and learning methods. Therefore this method will be utilized in Liepaja University to teach physics, especially electromagnetism

ON A MATHEMATICAL MODEL DESCRIBING OPTIMAL PROCESSING MECHANISM OF DISPERSED GRANULAR MATERIALS IN GRAVITATIONAL FLOW WITH HORIZONTAL OR INCLINED VIBRATING SIEVE CLASSIFYING SCREENS

The investigation of motion and gravitational processing of disperse granular materials is very important for solution of a wide spectrum of technological processes, including the chemical technology of treatment (with or without the decoration-compression procedure) of granular mineral fertilizers and their drying and sorting/separation by means of vibrating sieve classifying screens, in particular. In this work, we have used the apparatus of the theory of continuous media for the mathematical modelling of dynamics of disperse granular materials, and by this we assume that a property of these materials is the distribution of a solid granular component inside of them. The elaborated mathematical model is based on the volume conservation law for granular components, on the momentum conservation law, as well as on the equations for stress tensor in the granular mineral fertilizers and equations for description of the Coulomb granular mineral fertilizers

On one Mathematical Model for Dynamics of Propagation and Retention of Heat over New Fibre Insulation Coating

In circumstances, when it is important to replace insulation materials with high content of emissions during production it is necessary to create new heat and sound insulation material, which eliminates CO2 emissions, develop its production techniques and technological machinery – raw material chopper, pulp mixer, termopress, dryer chamber, formatting knifes, determine technical control parameters and control equipment, develop mathematical model of the material and calculation methods for design works. It is necessary to design, manufacture and experimentally test the respective technological equipment for insulation production pilot plant. To get exact physical parameters it is necessary design, manufacture and test unique laboratory equipment for determining the properties of insulation material. The mathematical model describing the dynamics of propagation and retention of heat over fibre insulation coating by taking "inner" specificities (graininess and porosity of layered structure of the considered fibre insulation) of heat insulator into account is proposed in the present paper

MARBLED CRAYFISH (PROCAMBARUS VIRGINALIS) AS A PROMISING OBJECT FOR AQUACULTURE INDUSTRY

Marbled crayfish / marmorkrebs, parthenogenetically reproducing decapod crustacean of pet aquarium origin conventionally has been recognized as an undesirable species since it a) is an invasive pest dangerous for aquatic ecosystem resources because of its hardiness, omnivorousness, fast growth, self-cloning abilities; b) has little commercial value for food industry. However, recently an idea has been introduced about marmorkrebs as a promising cheap protein source, which can help to fight world hunger. Accordingly, research performed at Liepaja University (Latvia) was focused on marbled crayfish farming system design issues. Research paper presented discusses marmorkrebs survival capacities in small-volume microcosm tanks (made from recycled material), under harsh abiotic conditions. Pilot research results obtained will be used to develop experimental project on low-input microcosmic indoor aquaculture for marmorkrebs

Test Equipment for Axial Flux Electrical Machines

Research bench was developed for electrical machine tests basically in generator mode. It consists of two parts. First part holds drive DC motor, researched machine and DC motor drive module, second part holds measurement panel, voltage and current transformer block and load rheostats. While drive motor runs researchable machine, measurement panel displays amounts of four physical values: voltage, current, frequency and temperature. Main developments within this bench are: DC motor drive, which is single phase controlled rectifier; frequency counter and frequency counter based RMS voltmeter. The IC MC14553BCP is used as 3 decade counter/driver/multiplexer which is the simplification key in frequency counter circuits. As RMS detector in voltmeters is used IC LTC1966, which gives low cost and high precision performance. Measurement transformer block allows to measure voltage and current in three phases just by switching the phase selector

Approximate Calculation Algorithm for Single Phase Bridge Rectifier with Capacitor Filter

In the paper approximate calculation algorithm for single phase rectifier with C filter is described. The offered algorithm contains formulas which allow determining capacitor current, total power factor as well as capacitor rated ripple current and equivalent series resistance without referring to datasheet. Although the formulas used in this algorithm are based on simplified mathematical models, there are influential circuit parameters observed such as transformer leakage inductive reactance, diode slope resistance and diode commutation interval. The algorithm corresponds to the analyzer style. It means that there are completely given single phase transformer, diodes, capacitor battery parameters and load resistance, and the analyzer finds out voltages, currents and powers. The algorithm contains only evaluated formulas so there is no need for advanced mathematics operations. It is tested on MS Excel. Calculation in Excel is not fully automated: there are two manually operable cells for leading the iteration process to its convergenc

Research Bench for Electrical Machines

Research bench was developed for electrical machine tests basically in generator mode. It consists of two parts. The first part holds the drive DC motor, researched machine and DC motor drive module, the second part holds the measurement panel, voltage and current transformer block and load rheostats. While the drive motor runs the researchable machine, the measurement panel displays the amounts of four physical values: voltage, current, frequency and temperature. The main developments within this bench are: DC motor drive, which is single phase controlled rectifier; frequency counter and frequency counter based RMS voltmeter. The IC MC14553BCP is used as 3-decade counter/driver/multiplexer which is the simplification key in frequency counter circuits. As RMS detector in voltmeters IC LTC1966 is used, which gives low cost and high precision performance. The measurement transformer block allows measuring the voltage and current in three phases just by switching the phase selector

Digital Aids’ Using at Lectures of Programming in RTU Liepaja Branch

The paper describes and illustrates one of the today‘s methodologies of teaching, which was used at lectures of programming in Riga Technical University Liepaja Branch. The objective methodology is to improve quality of a teaching process. The method is based on the use of original presentations, which provide studies of programming process in dynamic. Efficiency of the method is mentioned