This article describes a module and method for measuring the surface tension of liquid solders implemented on a measuring device as part of an integrated platform for automatic measurement of brazebility parameters at high temperatures. A concept for constructing a test stand is presented, with a description of the individual functional blocks. The developed stand allows for testing of the solder’s surface tension. The surface tension is one of the parameters that describe the thermodynamics of interfacial reactions and the structure of newly created joints. Determining the physicochemical interactions between liquid and solid substances is crucial for various industrial processes in fields such as metallurgy, electronics, and aviation, mainly where soldering and brazing technologies are employed. A series of bubble experiments in solder for a ceramic capillary is carried out to verify the proposed method using the developed system. One of these experiments is described in this article.

This paper proposes a simple mathematical model based on the variable fractional-order difference equation of a robot arm. The model of the described arm does not consider the impact of the movement of the mobile platform, it was assumed that all degrees of freedom would be taken away from it. The implementation of the task was divided into two stages. First, a mechanical model was developed. In order to estimate the torques of nodal propulsion motors, a description of the components of the Lagrange equation for the considered system, i.e., energy, power, and external interactions, and derivation of the equations of motion of the tested manipulator based on the Lagrange equation was made. An additional criterion was also considered in the selection of drives in the kinematic nodes of the links, which was to set the manipulator in a vertical position at a specific time. Processing the measured data of a robot arm, model parameters were selected, and the order function was chosen. The second stage was a simulation, whose results were compared with the collected data.

Determination of the physico-chemical interactions between liquid and solid substances is a key technological factor in many industrial processes in metallurgy, electronics or the aviation industry, where technological processes are based on soldering/brazing technologies. Understanding of the bonding process, reactions between materials and their dynamics enables to make research on new materials and joining technologies, as well as to optimise and compare the existing ones. The paper focuses on a wetting force measurement method and its practical implementation in industrial applications. Soldering simulation is a process in which simulation tools are used to model and simulate soldering processes. With simulation, different soldering methods and parameters can be tested to identify the best approach and minimize the risk of errors and failures in the real process. Soldering simulation can be used to optimize the soldering process and increase productivity, as well as to train personnel.

Online exams have become a common tool in the academic didactic process, as well as in most online courses in business. Taking exams in a remote location like home, using ICT tools, brings many challenges to both sides, the learner and the examiner. The aim of this article is to show the challenges in the context of ethical attitudes, trust, and respect for one another. Some results of a broader survey in the form of Computer Aided Web Interviews are presented to highlight students’ opinions and expectations, along with the results of personal interviews with academic teachers. In the final part of the article, recommendations are given. The importance of trust and systematic assessment of learners’ progress is emphasized.

This is a continuation (Part II) of our previous paper [19]. In this paper we present a simple method of the fractional-order value calculation of the fractional-order discrete integration element. We assume that the input and output signals are known. The linear time-invariant fractional-order difference equation is reduced to the polynomial in a variable ν with coefficients depending on the measured input and output signal values. One should solve linear algebraic equation or find roots of a polynomial. This simple mathematical problem complicates when the measured output signal contains a noise. Then, the polynomial roots are unsettled because they are very sensitive to coefficients variability. In the paper we show that the discrete integrator fractional-order is very stiff due to the degree of the polynomial. The minimal number of samples guaranteeing the correct order is evaluated. The investigations are supported by a numerical example.

This paper presents integer and linear time-invariant fractional order (FO) models of a closed-loop electric individual-wheel drive implemented on an autonomous platform. Two discrete-time FO models are tested: non-commensurate and commensurate. A classical model described by the second-order linear difference equation is used as the reference. According to the sum of the squared error criterion (SSE), we compare a two-parameter integer order model with four-parameter non-commensurate and three-parameter commensurate FO descriptions. The computer simulation results are compared with the measured velocity of a real autonomous platform powered by a closed-loop electric individual-wheel drive.

The growing number of operations in implementations of the non-local fractional differentiation operator is cumbersome for real applications with strict performance and memory storage requirements. This demands use of one of the available approximation methods. In this paper, the analysis of the classic integer- (IO) and fractional-order (FO) models of the brushless DC (BLDC) micromotor mounted on a steel rotating arms, and next, the discretization and efficient implementation of the models in a microcontroller (MCU) is performed. Two different methods for the FO model are examined, including the approximation of the fractional-order operator s ν ( ν ∈ R ) using the Oustaloup Recursive filter and the numerical evaluation of the fractional differintegral operator based on the Grünwald–Letnikov definition and Short Memory Principle. The models are verified against the results of several experiments conducted on an ARM Cortex-M7-based STM32F746ZG unit. Additionally, some software optimization techniques for the Cortex-M microcontroller family are discussed. The described steps are universal and can also be easily adapted to any other microcontroller. The values for integral absolute error (IAE) and integral square error (ISE) performance indices, calculated on the basis of simulations performed in MATLAB, are used to evaluate accuracy.

The aim of the article is to apply selected business processes modelling notation BPMN in e-learning design to enable the e-learning team to use ADDIE methodology decomposed as a process.In the first part of the article some basic issues of the educational and organizational context of the process are presented.The second part explains the ADDIE methodology.Next, BPMN implementation in designing the online course process is proposed.The article is an introductory part of research aiming to optimize e-learning creation processes in business.

STATEMENT OF PROBLEM:The wettability of the framework by liquid ceramics is important in ensuring a suitable bond between veneering ceramics and zirconia. PURPOSE:The purpose of this in vitro study was to examine the dependence of the wetting angle on temperature to determine the transition temperature from nonwettable to wettable states and to calculate the values of the relative wetting forces of the milled surfaces. MATERIAL AND METHODS:Fifty zirconia cylinders were divided into 5 groups (n=10) and subjected to the following treatments: milling, grinding, polishing, and airborne-particle abrasion with Al2O3 or SiC. After treatment, the specimens were rinsed, dried, and examined with respect to their wettability by liquid ceramics by using the automated Thermo-Wet test bench. The results were statistically analyzed by an ANOVA (α=.05). RESULTS:The most rapid wettability was obtained through airborne-particle abrasion with Al2O3 at 930 °C. Additionally, the highest relative bond strength (with respect to the machined surface) was obtained with Al2O3 abrasion. CONCLUSIONS:Because of variations in the wettability of the zirconia surface after different treatment methods, the firing temperature of the ceramic should also vary depending on the type of surface treatment applied. Thus, it is determined individually according to the chosen method.

In the paper we analyse a fractional-order linear state-space model with multiple delays. We show that the multiple delay in the fractional-order state-space model introduces higher integer-order discrete differentiation action. Two fractional order state-space models without delays are derived. The equivalent models may be useful in the system stability analysis. The investigations are supported by numerical examples.

In the paper we investigate the fractional-order evaluation of the fractional-order discrete integration element. We assume that the input and output signals are known. The main problem is to calculate fractional-order value. From a theoretical point of view there is no mathematical problem of the solution. One should solve linear algebraic equation or find roots of a polynomial in a variable v. The problem arises when the measured output signal contains a noise. Then, the solution is unsettled because the polynomial roots are very sensitive to coefficients variability. In the paper we propose a method of evaluating of the discrete integrator fractional-order. The investigations are supported by numerical example.

Ultrasonografia Dopplerowska jest jednym z najlepszych sposobów diagnozy zmian miażdżycowych oraz szczegółowej kontroli patologii zmian ścian naczyń krwionośnych. Wykonanie badania wymaga szeregu czynności wykonywanych współbieżnie, m.in. analizy obrazów USG oraz ręcznego sporządzania notatek na potrzeby podsumowania badania. Analiza problemu wykazała, że przebieg badań ultrasonograficznych może zostać częściowo zautomatyzowany przez dedykowane oprogramowanie, co przedstawia niniejszy artykuł.

Determination of the physico-chemical interactions between liquid and solid substances is a key technological factor in many industrial processes in metallurgy, electronics or the aviation industry, where technological processes are based on soldering/brazing technologies. Understanding of the bonding process, reactions between materials and their dynamics enables to make research on new materials and joining technologies, as well as to optimise and compare the existing ones. The paper focuses on a wetting force measurement method and its practical implementation in a laboratory stand – an integrated platform for automatic wetting force measurement at high temperatures. As an example of using the laboratory stand, an analysis of Ag addition to Cu-based brazes, including measurement of the wetting force and the wetting angle, is presented.

Niniejsza praca powstala w ramach realizacji projektu badawczego mającego na celu opracowanie i wdrozenie technologii recyklingu poprodukcyjnych odpadow taśmy stalowej. W ramach prowadzonych prac wykonano procesy oczyszczania blach metodami obrobki strumieniowo-ściernej, a nastepnie tak oczyszczone blachy poddawano procesowi walcowania. Po procesie walcowania nakladano, metodą zanurzeniową, powloke cynkową. W pracy przedstawiono wplyw gniotu podczas obrobki plastycznej na zwilzanie powierzchni blach stalowych cieklym cynkiem. Badaniom poddano blachy obrobione ścierniwem Al2O3, ktore zostaly potem poddane walcowaniu z roznymi gniotami (20, 40, 60 i 80%). Na tak przygotowanych probkach przeprowadzono badania na specjalnie zaprojektowanym stanowisku dynamiki zwilzania metodą meniskograficzną umozliwiającą wykonanie kompleksowych badan wlasności dynamicznych powierzchni – napiecia powierzchniowego oraz zwilzalności. Z przeprowadzonych badan wynika, ze najlepsza zwilzalnośc osiągana jest dla probek o gniocie 20%, dla ktorych graniczny kąt zwilzania wynosi ok. 60°. Im wiekszy gniot, tym gorsza zwilzalnośc blach stalowych cieklym cynkiem. Mozna zauwazyc, ze jeszcze tylko dla probki z gniotem 40% zarejestrowano kąt zwilzania ponizej 90° (wynosil on okolo 80°). Mozna powiedziec, ze tylko te probki byly zwilzane cieklym cynkiem. Dla pozostalych dwoch zarejestrowane wartości kąta zwilzania byly znacznie powyzej 90° przyjetych, jako granica przejścia z braku zwilzania do zwilzania. Reasumując uzyskane wyniki badan, mozna stwierdzic, ze zwiekszenie stopnia zgniotu podczas procesu walcowania zmniejsza zwilzalnośc obrobionej powierzchni cieklym cynkiem.

The use of ICT enables enterprises to increase their overall efficiency and makes them more competitive. Bailiff office can be an example of a firm not from ICT branch, but widely using new information technologies. The idea of this paper is to show some modifications of existing algorithms of an information system for a bailiffs office to enhance its efficiency. This concerns selected processes essential for efficient work of the office. In the first part of the paper the needs and the opportunities of information technologies for the bailiffs are shown. The necessity of EDI use especially in a bailiffs office has been pointed. Some work areas of the application Komornik SQL where efficiency problems appear have also been presented. These caused lower work of the whole team. Then solutions tending to eliminate human error and manual data introducing as well as its verification have also been described. Four algorithms improving the mentioned system are presented.

Abstract The good quality of several manufactured components frequently depends on solidliquid interactions existing during processing. Nowadays, the research in material engineering focuses also on modern, automatic measurement methods of joining process properties, i.a. wetting force and surface tension, which allows for quantitative determination of above mentioned parameters. In the paper, the brazes’ dynamic properties in high-temperatures’ measurement methodology and the stand for automatic determination of braze’s properties, constructed and implmented within the research grant nr KBN N N519 441 839 - An integrated platform for automatic measurement of wettability and surface tension of solders at high temperatures, are widely described

Abstract The article presents the construction of a new device that has been formed within the frames of a grant nr KBN N N519 441 839 - An integrated platform for automatic measurement of wettability and surface tension of solders at high temperatures. The authors have presented methodology and analytical concept of surface tension measurement using maximum pressure in gas bubble method. The results of examplary experiments are presented.