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Gdańsk University of Technology

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Publications from the year 2021

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  • A MEASUREMENT SYSTEM FOR MONITORING CARDIOVASCULAR EVENTS IN SYNCOPE PATIENTS
    • Michał Pietrewicz
    • Katarzyna Mazur
    • Ewa Wagner-Wysiecka
    2021

    Syncope phenomena is an abrupt and transient loss of consciousness leading to interruption of awareness of one’s surroundings and falls with risk of injury. Syncope is often followed by complete and usually rapid spontaneous recovery. It is said that half of all individuals experience syncopal event at least once during their life. The condition can occur at any age and happens in people with and without other medical problems. The underlying mechanism is global hypoperfusion of both the cerebral cortices or focal hypoperfusion of the reticular activating system. Decreased cerebral perfusion is common to most causes of syncope. Cessation of a cerebral perfusion for even a short time, as 3-5 seconds, could result in syncope. Decreased cerebral perfusion may occur as a result of decreased both cardiac output or systemic vascular resistance. There are several different types of syncope which derive from different etiologies such as the neurally-mediated (reflex) syncope, orthostatic hypotension which may be caused by dehydration or due to medication and the cardiovascular derived syncopal events which are most dangerous ones. The most common syncope event is called vasovagal syncope. Such commonfaint may be experienced by normal persons with no evidence of any heart disease. Vasovagal syncope is the most common cause of such phenomena in young adults. As in other forms of neurally-mediated reflex syncope, it is due to systemic hypotension resulting in a transient period of inadequate cerebral blood flow. Vasovagal syncope can be preceded by such symptoms as pallor, nausea, sweating or heart palpitations. It often occurs when person is exposed to the prolonged standing, heat, emotional stress, trauma or pain etc. During and after the syncopal event the headache, confusion, discomfort and chest pain may occur, but there are many events that end up with no side effects at all. Overall, even if the syncopal event may have no side effects, it impacts patient quality of life and often may lead to dramatic consequences of self-injury or risk of danger for surrounding people (e.g. syncopal event occurring while driving a car). Monitoring cardiovascular events in syncope patients is tough and challenging issue.

  • A Method for Underwater Wireless Data Transmission in a Hydroacoustic Channel under NLOS Conditions
    • Jerzy Mizeraczyk
    • Ryszard Studanski,
    • Andrzej Zak
    • Agnieszka Czapiewska
    2021 Full text SENSORS

    Wireless data transmission in the hydroacoustic channel under non-line-of-sight (NLOS) propagation conditions, for example, during a wreck penetration, is difficult to implement reliably. This is mostly due to the multipath propagation, which causes a reduction in the quality of data reception. Therefore, in this work an attempt has been made to develop a reliable method of wireless underwater communication test it under the NLOS conditions. In our method, we used multiple frequency-shift keying (MFSK) modulation, sending a single bit on two carriers, and diversity combining. The method was tested in laboratory conditions which simulated underwater signal propagation during the penetration of the wreck. The propagation conditions were investigated by determining the impulse responses at selected measurement points using the correlation method. Additionally, for comparison, the data transmission quality was determined by the bit error rate (BER) under the same conditions using direct sequence spread spectrum (DSSS) and binary phase shift keying (BPSK) modulation. The obtained results confirmed the usefulness of the application of the developed method for wireless data transmission in a hydroacoustic channel under NLOS conditions.

  • A method of predicting the best conditions for large-size workpiece clamping to reduce vibration in the face milling process
    • Krzysztof Kaliński
    • Natalia Stawicka-Morawska
    • Marek Galewski
    • Michał Mazur
    2021 Full text Scientific Reports

    The paper presents an innovative method of solving the problem of vibration suppression during milling of large-size details. It consists in searching for the best conditions for clamping the workpiece based on a rapid modal identification of the dominant natural frequencies only and requires repetitive changes in the tightening torque of the clamping screws. Then, by estimating the minimum work of the cutting forces acting in the direction of the width of the cutting layer, it is possible to predict the best fixing of the workpiece. Application of the method does not require the creation and identification of a computational model of the process or preliminary numerical simulations. The effectiveness of this method was confirmed by the evaluation of the Root Mean Square (RMS) of the vibration level in the time domain observed during the actual face milling process. The worst results were obtained for the configuration of supports tightened with a torque of 90–110 Nm, and the best—with a torque of 50 Nm.

  • A Microwave Sensor with Operating Band Selection to Detect Rotation and Proximity in the Rapid Prototyping Industry
    • Abhishek Jha
    • Adam Lamęcki
    • Michał Mrozowski
    • Bozzi Maurizio
    2021 Full text IEEE TRANSACTIONS ON INDUSTRIAL ELECTRONICS

    This paper presents a novel sensor for detecting and measuring angular rotation and proximity, intended for rapid prototyping machines. The sensor is based on a complementary split-ring resonator (CSRR) driven by a conductor-backed coplanar waveguide. The sensor has a planar topology, which makes it simple and cost-effective to produce and accurate in measuring both physical quantities. The sensor has two components, a rotor, and a stator: the first of these can rotate around its axis and translate along the plane normal to the ground. A detailed theoretical and numerical analysis, along with a circuit model, of the unique sensor design is presented. The proposed sensor exhibits linear response for measuring angular rotation and proximity in the range of 30×60 degrees and 0-200 μm. Another distinctive feature of the rotation and proximity sensor is the wide frequency band of applicability, which is an integral part of its novel design and is implemented through various dielectric material loadings on the CSRR. The stator was fabricated on RF-35 substrate, while the CSRR-based rotor was fabricated on TLY-5 and RF-35 substrates. The angular rotation, the proximity, the operating band selection, and the sensitivity were measured using a vector network analyzer and were found to be good matches to the simulated and theoretical result

  • A Model-Order Reduction Approach for Electromagnetic Problems With Nonaffine Frequency Dependence
    • Grzegorz Fotyga
    2021 Full text IEEE Access

    The aim of this paper is to present a novel model-order reduction (MOR) technique for the efcient frequency-domain nite-element method (FEM) simulation of microwave components. It is based on the standard reduced-basis method, but the subsequent expansion frequency points are selected following the so-called sparsied greedy strategy. This feature makes it especially useful to perform a fast-frequency sweep of problems that lead to systems of equations exhibiting a nonafne frequency dependence. This property appears, for example, when the excitation of the problem is characterized by a frequency-dependent waveguide mode pattern, or when the computational domain includes materials with frequency-dependent permittivity or permeability tensors. Moreover, the new MOR scheme can be also used to accelerate the frequency sweep of problems with many excitations, for which the standard reduction algorithms tend to be time-consuming. Its effectiveness and accuracy is veried through analysis of three microwave structures: planar microstrip branch-line coupler, three-port waveguide junction with ferrite post, and an eighth-order dual-mode waveguide lter.

  • A multi-criteria decision model for the introduction of electric storage multiple units on the partially electrified Gdynia-Hel railway
    • Natalia Karkosińska-Brzozowska
    • Paweł Stromski
    • Dariusz Karkosiński
    2021 Full text Pojazdy Szynowe

    : In this article a multi-criteria study of the use of independently powered electric multiple units on the partially electrified Gdynia Główna - Hel line was carried out. The use of (currently used) diesel and, as an alternative, electric and electric multiple units with an electric energy storage was considered. The analysis was carried out on the basis of three criteria for assessing the route service options, i.e. environmental, economic, operational and economic investment criteria. A multi-criteria decision model was developed for the analysis and a comparative analysis of the considered options for servicing the Gdynia Główna - Hel route was carried out. As part of the environmental criterion, it was found that the most environmentally friendly use of storage units. As part of the operational economic criterion, it was shown that the storage units have the lowest operating costs. The analysis as part of the investment cost criterion showed that the lowest investment costs are characteristic of route operation with the use of combustion units. The highest investment costs are related to the route operation by classic electric units, which is associated with the complete electrification of the line.

  • A new 1-nitro-9-aminoacridine derivative targeting yeast topoisomerase II able to overcome fluconazole-resistance
    • Kamila Rząd
    • Ewa Paluszkiewicz
    • Iwona Gabriel
    2021 BIOORGANIC & MEDICINAL CHEMISTRY LETTERS

    Fungal resistance remains a significant threat and a leading cause of death worldwide. Thus, overcoming microbial infections have again become a serious clinical problem. Although acridine derivatives are widely analyzed as anticancer agents, only a few reports have demonstrated their antifungal activity. In an effort to develop biologically active antifungals, twelve novel C-857 (9-(2′ -hydroxyethylamino)-1-nitroacridine) and C-1748 (9-(2′ -hydroxyethylamino)-4-methyl-1-nitroacridine) derivatives were synthesized. The evaluation of biological properties suggests that starting compounds: C-1748, C-857 and IE3 (2-[(4-methyl-1-nitroacridin-9- yl)amino]ethyl lysinate), IE4 (2-[(1-nitroacridin-9-yl)amino]ethyl lysinate) antifungal mode of action differ from that determined for IE5 (N′ -{3-[(4-methyl-1-nitroacridin-9-yl)amino]propyl}lysinamide), IE6 (N′ -{3-[(1-nitroacridin-9-yl)amino]propyl}lysinamide) and IE10 (3,3′ -Bis-(1-nitroacridin-9-ylamino) aminoethylaminoethylaminoethylamine). Although MIC values determined for the latter were higher, in contrast to C-857 and C-1748, newly synthesized IE5, IE6 and IE10 reduced C. albicans hyphal growth in different inducing media. Those compounds also exhibited antibiofilm activity, whereas IE10 was the most effective. Moreover, only IE6 exhibited antifungal activity against fluconazole resistant C. albicans strains with MICs values in the range of 16–64 μg mL- 1. Our results also indicate that, in contrast to other analyzed derivatives, novel synthetized compounds IE6 and IE10 with antifungal activity target yeast topoisomerase II activity.

  • A New Adaptive Method for the Extraction of Steel Design Structures from an Integrated Point Cloud
    • Paweł Burdziakowski
    • Angelika Zakrzewska
    2021 Full text SENSORS

    The continuous and intensive development of measurement technologies for reality modelling with appropriate data processing algorithms is currently being observed. The most popular methods include remote sensing techniques based on reflected-light digital cameras, and on active methods in which the device emits a beam. This research paper presents the process of data integration from terrestrial laser scanning (TLS) and image data from an unmanned aerial vehicle (UAV) that was aimed at the spatial mapping of a complicated steel structure, and a new automatic structure extraction method. We proposed an innovative method to minimize the data size and automatically extract a set of points (in the form of structural elements) that is vital from the perspective of engineering and comparative analyses. The outcome of the research was a complete technology for the acquisition of precise information with regard to complex and high steel structures. The developed technology includes such elements as a data integration method, a redundant data elimination method, integrated photogrammetric data filtration and a new adaptive method of structure edge extraction. In order to extract significant geometric structures, a new automatic and adaptive algorithm for edge extraction from a random point cloud was developed and presented herein. The proposed algorithm was tested using real measurement data. The developed algorithm is able to realistically reduce the amount of redundant data and correctly extract stable edges representing the geometric structures of a studied object without losing important data and information. The new algorithm automatically self-adapts to the received data. It does not require any pre-setting or initial parameters. The detection threshold is also adaptively selected based on the acquired data.

  • A New Approach to the PWM Modulation for the Multiphase Matrix Converters Supplying Loads with Open-End Winding.
    • Paweł Szczepankowski
    • Natalia Strzelecka
    • Enrique Romero-Cadaval
    2021 Full text ENERGIES

    This article presents three variants of the Pulse Width Modulation (PWM) for the Double Square Multiphase type Conventional Matrix Converters (DSM-CMC) supplying loads with the open-end winding. The first variant of PWM offers the ability to obtain zero value of the common-mode voltage at the load's terminals and applies only six switches within the modulation period. The second proposal archives for less Total Harmonic Distortion (THD) of the generated load voltage. The third variant of modulation concerns maximizing the voltage transfer ratio, minimizing the number of switching, and the common-mode voltage cancellation. The discussed modulations are based on the concept of sinusoidal voltage quadrature signals, which can be an effective alternative to the classic space-vector approach. In the proposed approach, the geometrical arrangement of basic vectors needed to synthesize output voltages is built from the less number of vectors, which is equal to the number of the matrix converter's terminals. The PWM duty cycle computation is performed using only a second-order determinant of the voltages coordinate matrix without using trigonometric functions. A new approach to the PWM duty cycles computing and the load voltage synthesis by 5x5 and 12x12 topologies has been verified using the PSIM simulation software.

  • A new concept of contemporary marketing
    • Anna Drapińska
    2021

    Purpose: This conceptual paper aims to propose a new concept of marketing that responds well to the needs of a changing world, taking into account the continuous development of the service economy and the revolution in the development of the Internet and related tools. Methodology/Approach: The proposed concept is based on well-researched theories: service marketing, experience marketing, relationship marketing and digital marketing (4.0). An in-depth review of marketing literature has been conducted. The proposed concept uses such terms as interactions, relationships, experiences, and digital marketing. Findings: The main achievement is a new concept of contemporary marketing. Its essence is the creation by organizations of long-term relationships with customers, through interactions and consistent customer experiences both in the offline and online world. Originality/value: The paper proposes a new look at contemporary marketing, indicates its elements and essence and contributes both to the development of the theory and research in marketing.

  • A New Direct-Sequence Spread Spectrum Signal Detection Method for Underwater Acoustic Communications in Shallow-Water Channel
    • Iwona Kochańska
    2021 Full text Vibrations in Physical Systems

    Direct-Sequence Spread Spectrum (DSSS) is one of the modulation and coding techniques used in Underwater Acoustic Communication (UAC) systems for reliable data transmision even at low signal levels. However, in a shallow water channel, there is a strong multipath propagation which causes a phase fluctuation of the received signal, affecting the performance of the spread-spectrum system. The article presents a differential method for DSSS signal detection. It is based on the calculation of the correlation coefficient of adjacent segments of signal at the output of filter matched to the spreading sequence used in the transmitter. A positive value of the correlation coefficient means that a given modulation symbol carries the same information bit as the previous one; a negative value means that the opposite bit has been transmitted. The reliability of the proposed method has been compared to classical method of DSSS signal detection, which consists in detecting the information directly from the signal at the output of the matched filter. Simulation and measurement tests of underwater acoustic communications in strong multipath propagation conditions have shown that the proposed method allows obtaining lower values of the DSSS transmission Bit Error Rate (BER) than the classical detection technique while maintaining the same data transmission rate.

  • A new multi-process collaborative architecture for time series classification
    • Zhiwen Xiao
    • Xingtao Xu
    • Haoxi Zhang
    • Edward Szczerbicki
    2021 Full text KNOWLEDGE-BASED SYSTEMS

    Time series classification (TSC) is the problem of categorizing time series data by using machine learning techniques. Its applications vary from cybersecurity and health care to remote sensing and human activity recognition. In this paper, we propose a novel multi-process collaborative architecture for TSC. The propositioned method amalgamates multi-head convolutional neural networks and capsule mechanism. In addition to the discovery of the temporal relationship within time series data, our approach derives better feature extraction with different scaled capsule routings and enhances representation learning. Unlike the original CapsNet, our proposed approach does not need to reconstruct to increase the accuracy of the model. We examine our proposed method through a set of experiments running on the domain-agnostic TSC benchmark datasets from the UCR Time Series Archive. The results show that, compared to a number of recently developed and currently used algorithms, we achieve 36 best accuracies out of 128 datasets. The accuracy analysis of the proposed approach demonstrates its significance in TSC by offering very high classification confidence with the potential of making inroads into plentiful future applications.

  • A note on the applications of artificial intelligence in the hospitality industry: preliminary results of a survey
    • Joanna Citak
    • Mieczysław Owoc
    • Paweł Weichbroth
    2021 Full text

    Intelligent technologies are widely implemented in different areas of modern society but specific approaches should be applied in services. Basic relationships refer to supporting customers and people responsible for services offering for these customers. The aim of the paper is to analyze and evaluate the state-of-the art of artificial intelligence (AI) applications in the hospitality industry. Our findings show that the major deployments concern in-person customer services, chatbots and messaging tools, business intelligence tools powered by machine learning, and virtual reality & augmented reality. Moreover, we performed a survey (n = 178), asking respondents about their perceptions and attitudes toward AI, including its implementation within a hotel space. The paper attempts to discuss how the hotel industry can be motivated by potential customers to apply selected AI solutions. In our opinion, these results provide useful insights for understanding the phenomenon under investigation. Nevertheless, since the results are not conclusive, more research is still needed on this topic. Future studies may concern both qualitative and quantitative methods, devoted to developing models that: a) quantify the potential benefits and risks of AI implementations, b) determine and evaluate the factors affecting the AI adoption by the customers, and c) measure the user (guest) experience of the hotel services, fueled by AI-based technologies.

  • A Novel Versatile Decoupling Structure and Expedited Inverse-Model-Based Re-Design Procedure for Compact Single-and Dual-Band MIMO Antennas
    • Muhammad Abdullah
    • Sławomir Kozieł
    2021 Full text IEEE Access

    Multiple-input multiple-output (MIMO) antennas are considered to be the key components of fifth generation (5G) mobile communications. One of the challenges pertinent to the design of highly integrated MIMO structures is to minimize the mutual coupling among the antenna elements. The latter arises from two sources, the coupling in the free space and the coupling currents propagating on a ground plane. In this paper, an array of H-shaped parasitic patches is proposed as a decoupling structure for compact MIMO antennas to reduce propagation of the coupling currents on a shared ground plane. The proposed decoupling structure is generic, and it can be applied to different antenna configurations as demonstrated in the work. Furthermore, it is employed to develop a new high-performance compact dual-band MIMO structure featuring acceptable level of element coupling at both operating frequencies. The design is validated both numerically and experimentally. The mutual coupling levels are less than -17 dB and -20 dB, with the total efficiency of 89% and 90%, and the realized gain of 6.6 dB and 7 dB at the two resonant frequencies of 5 GHz and 6 GHz, respectively. Topological complexity of the compact MIMO systems featuring elaborated decoupling structures, a large number of geometry parameters, as well as the necessity of handling multiple performance figures, constitute the major challenges of antenna design, in particular, its re-design for various specifications. To alleviate these difficulties, the paper also provides a procedure for rapid geometry scaling of the dual-band MIMO antennas. Our approach is based on inverse surrogate modeling methods, and results in numerically-derived expressions that enable a precise control over the operating antenna bands within broad ranges thereof (from 4 GHz to 8 GHz for the lower band, and from 1.1 to 1.3 ratio of the upper to lower operating frequency). The aforementioned procedure is accompanied by an optimization-based design refinement scheme. A practical utility of the procedure is corroborated using multiple verification case studies as well as physical measurements of the antenna designed for the exemplary set of performance specifications.

  • A Panel Analysis of the Impact of Green Transformation and Globalization on the Labor Share in the National Income
    • Małgorzata Gawrycka
    • Anna Szymczak
    2021 Full text ENERGIES

    This study aims to examine the impact of green transition and globalization processes on changes in the labour share. The study covers 76 national economies diversified in development, global production share and energy transition stage from 2000 to 2018. Based on the Total Economy Database data, panel models of the relationship between green transition, globalization and the labour share in the national income were estimated. The conducted Breusch–Pagan and Hausman tests proved the validity of using fixed-effects models. We confirmed the research hypothesis that the openness of the economy contributes to a decline in the labour share. The openness of the economy resulting from globalization reduces the labour share in the national income. We do not confirm hypotheses that suggest energy transition contributes to a reduction in the labour share and that the labour share will decline in the post-crisis period due to the lower bargaining power of workers. Changes in the labour share should be of interest to government representatives who influence the shape and implementation of economic policy, especially in employment policy, education, and investment policy, mainly aimed at the green transformation.

  • A Pilot Study on Machining Difficult-to-Cut Materials with the Use of Tools Fabricated by SLS Technology
    • Mariusz Deja
    • Dawid Zieliński
    2021 Full text Materials

    The growing use of contemporary materials in various industrial sectors, such as aerospace, automotive, as well as the oil and gas industry, requires appropriate machining methods and tools. Currently, apart from the necessity to obtain high-dimensional and shape accuracy, the efficiency and economic aspects of the selected manufacturing process are equally important, especially when difficult-to-cut materials, such as hard and brittle ceramics, have to be machined. In the research presented in this paper, a prototype tool fabricated from polyamide powder by the SLS method was used in flat-lapping of Al2O3 ceramics, showing the promising potential and efficacy of rapid tooling and manufacturing in the area of abrasive machining. The influence of the selected input process factors, such as machining time, the type of abrasive suspension, kinematic parameters, and unit pressure, on technological effects, was analyzed. The microscopic observations of the active surface of the prototype tool showed its reinforcement with loose diamond abrasive particles (size D107), resulting in the effective material removal and improved surface finish of Al2O3 ceramic samples. The directions for further development of tools fabricated by the SLS method for applications in abrasive machining were also envisaged by the authors.

  • A pilot study to assess manufacturing processes using selected point measures of vibroacoustic signals generated on a multitasking machine
    • Mariusz Deja
    • Roksana Licow
    2021 Full text INTERNATIONAL JOURNAL OF ADVANCED MANUFACTURING TECHNOLOGY

    The article presents the method for the evaluation of selected manufacturing processes using the analysis of vibration and sound signals. This method is based on the use of sensors installed outside the machining zone, allowing to be used quickly and reliably in real production conditions. The article contains a developed measurement methodology based on the specific location of microphones and vibration transducers mounted on the tested object, in this case on a four-axis CNC ST20Y Haas lathe. A mobile phone was integrated into the measuring system and used to control the measurement process. The results from the analysis of vibration and sound signals recorded during different machining operations are presented. They refer to selected working conditions of a machine tool depending on switching the coolant supply on or off and different machine loads caused by various technological processing as well as the various speed of the positioning movements. The analysis was carried out using selected point measures describing the vibroacoustic signals. The synthesis conducted on the basis of results from the experiments indicates the validity of using vibration and acoustic signals, recorded outside the machining area, to evaluate material removal processes that are diverse in terms of kinematics and processing conditions. It indicates the possibility of using proposed point measures of vibroacoustic signals in the diagnostic aspects of the machine tools to achieve high dimension and shape accuracy and to evaluate the condition of the technological devices in terms of their optimal efficiency. Presented methodology can be used as a supporting tool in the CAD/CAM software for a better selection of appropriate cutting parameters and for a wireless control of manufacturing systems consisting of several machine tools.

  • A Qualitative Study on Non-functional Requirements in Agile Software Development
    • Aleksander Jarzębowicz
    • Paweł Weichbroth
    2021 Full text IEEE Access

    Widespread use of agile software development (ASD) methods can be observed nowadays. Non-functional requirements (NFRs) are often reported to be a problematic issue for agile projects, since ASD methods tend to neglect NFRs while focusing on incremental delivery of functional features. Despite that, only very few studies have explored the requirements engineering practices used in ASD and dedicated particularly to NFRs. Objective: We aimed to identify and investigate the practices used in industrial ASD projects to identify, elicit and document NFRs. Method: We conducted a systematic literature review (SLR) and used its findings to prepare an interview guide. We then conducted a series of semi-structured interviews with 10 experienced practitioners. Results: The SLR revealed a number of strategies related to the timing of NFR identification as well as 13 elicitation practices and 20 documentation techniques. At least some of these findings show discrepancies between ASD theory and practice. The interviews provided a more in-depth understanding of the practices used, and their context. The main findings from the interviews include: practitioners' attempts to start identifying NFRs early in the project, a lack of elicitation techniques aimed at NFRs only, and different choices about documentation techniques, including the additional techniques introduced to cope specifically with NFRs. Conclusions: It was not confirmed that requirements engineering activities related to NFRs are perceived by ASD practitioners as a problem, as they developed effective practices to deal with this issue. Moreover, our findings show that different approaches to NFRs can be used and give satisfactory results.

  • A review of recent advances in the single- and multi-degree-of-freedom ultrasonic piezoelectric motors
    • Roland Ryndzionek
    • Łukasz Sienkiewicz
    2021 Full text ULTRASONICS

    In this paper a comprehensive review of recent studies on the ultrasonic piezoelectric motors is presented. The analytical, numerical and experimental analysis. In further sections, classification methods of piezoelectric motors, survey criteria and three main groups of ultrasonic piezoelectric motors with examples have been presented and described. Finally, the conclusions and future research perspectives have been proposed.

  • A Review of Reduction Methods of Impact of Common-Mode Voltage on Electric Drives.
    • Marek Turzyński
    • Piotr Musznicki
    2021 Full text ENERGIES

    In this survey paper, typical solutions that focus on the reduction in negative effects resulting from the common-mode voltage influence in AC motor drive applications are re-examined. The critical effectiveness evaluation of the considered methods is based on experimental results of tests performed in a laboratory setup with an induction machine fed by an inverter. The capacity of a common-mode voltage level reduction and voltage gradient du/dt limitation is discussed to extend motor bearings’ lifetime and increase motor windings’ safety. The characteristic features of the described solutions are compared and demonstrated using laboratory results.