Cold-formed structure connections utilizing gusset plates are usually semi-rigid. This paper investigates the behaviours of rectangular gusset plates in cold-formed connections of elements whose columns and beams are made with lipped back-to-back C-sections. Methods of calculating strength and stiffness are necessary for such semi-rigid joints. The main task of this paper is to determine a method capable of calculating these characteristics. The proposed analytical method could then be easily adapted to the component method that is described in part 1993-1-8 of the Eurocode. This method allows us to calculate both the strength and stiffness of rectangular gusset plates, assuming that the joint deforms only in plane. This method of design moment resistance calculation was presented taking into account that an entire cross-section shall reach its yield stress. A technique of stiffness calculation was presented investigating the sum of deformations acquired at the bending moment and from shear forces which are transmitted from each beam bolt group. Calculation results according to the suggested method show good agreement of laboratory experimental results of specimens with numerical simulations. Two specimens of beam-to-column connections were tested in the laboratory. Lateral supports were used on the specimens to prevent lateral displacements in order to better investigate the behaviour of the rectangular gusset plate in plane. Experiments were simulated by modelling rectangular gusset plates using standard finite element software ANSYS Workbench 14.0. Three-dimensional solid elements were used for modelling and both geometric and material nonlinear analysis was performed.

The paper presents achievements in gluing technique in steel and aluminium structures. Adhesives currently in use and available on the market are characterized from the point of view of their mechanical properties. Design rules of adhesive connections and basic methods for their calculations are mentioned. The most significant examples of the applications of those joints in steel as well as aluminium structures are shown.

The justification for the document Study of the Conditions and Directions of the Spatial Management of a Commune created by Cracow’s Municipality Planning Office, reveals the numerous of intercommunal dysfunctions included in these documents for different communes and shows differences between Studies and Voivodeship Spatial Management Plan of Małopolska. The main purpose of the article is the discussion on the issue, showing the research methodology of intercommunal relationships analysis (conducted in the Justification) and inquiry for the solutions in Polish law system, which could resolve the problem.

Crossing borders: between literature and science – Italian culture of the twentieth and twenty-first centuries has offered significant examples of renewal through crossing boundaries between different disciplines. Several writers (Levi, Calvino, Gadda, Sinisgalli, Del Giudice, Giordano, Arpaia, Odifreddi) have overcome the dichotomy between the two cultures that was denounced by Charles Snow in 1959. Sixty years after the famous essay by Snow, the paper will show several examples of connections between literature and science, by using the concept of the “four frontier customs”: “the transit”, “the trespass”, “the alliance”, and “the conflict”.

The article discusses the problem with modifications of plans of water areas and the forms of their borders which have been inscribed into the history of all city structures related to water. It can be observed that the modifications made in recent decades very often concern the transformations of former industrial sites. Many such structural changes are taking place within signifi cant areas which have fragmented central parts of cities and created voids in the urban fabric. They are being applied to many former shipyards and ports. Research shows that the formation of new connections between land and water in these transformation processes is essential. More frequently, those conversions that are currently being realized change the constructions of wharves and lead to the development of plans drawing new borders between land and water. In these cases water is introduced into land areas and new land surfaces are being created over existing bodies of water. These operations can be considered extremely valuable in achieving the intended eff ects of transformations of post-industrial areas. They are perceived as an excellent possibility to strengthen the relationship between the city structure and water. At the same time they create an opportunity to achieve a high quality of architectural and landscape solutions and the quality of spaces in both social and economic terms.

The purpose of the paper was to design geometric models of the movable connection made of brass for three different attachment options and three different loads. The numerical analysis of the mechanical properties, stresses, strains and displacements using the finite element method was carried out in SolidWorks 2020 and their comparative analysis was performed. The computer simulations performed will allow the boundary conditions that directly affect the mechanical properties of the engineering materials to be optimised.

The article is devoted to the research of the motif of deception in the fairy‑tales of the Polish and Ukrainian writer S. Ostashevskyi. The work offers arguments for the topicality of the research as well as for the choice of the analysis methodology. It also emphasizes the significance of studying the author’s creative works with a view to revealing those connections between Ukrainian and Polish culture which indisputably prove their kinship. Four types of the deception motif have been distinguished based on the collections of fairy‑tales Half‑a‑Kopa Fairy‑Tales for the Little World and Half‑a‑Hundred Fairy‑Tales for Jolly People. These types are as follows: “a creature with superpowers deceives people by appearing in front of them in an anthropomorphous, intentionally inferior, everyday image”, “an infernal character takes people in without changing its image but promising material benefits and solutions to people’s life problems in exchange for their own souls or their children’s souls”, “a person (usually, a woman) deceives/tries to deceive an infernal character or some supreme forces in general”, and “a person deludes another person”. The comparison of this material with the corresponding folklore and literary heritage has defined the specificity of using and transforming the deception motif by S. Ostashevskyi: dependence on the expression of the religious idea, comical play such as appears in the 19th‑century burlesque and travesty art, and reflection on the harmonious combination of Ukrainian and Polish folklore traditions.

Overseas mining investment generally faces considerable risk due to a variety of complex risk factors. Therefore, indexes are often based on conditions of uncertainty and cannot be fully quantified. Guided by set pair analysis (SPA) theory, this study constructs a risk evaluation index system based on an analysis of the risk factors of overseas mining investment and determines the weights of factors using entropy weighting methods. In addition, this study constructs an identity-discrepancycontrary risk assessment model based on the 5-element connection number. Both the certainty and uncertainty of the various risks are treated uniformly in this model and it is possible to mathematically describe and quantitatively express complex system decisions to evaluate projects. Overseas mining investment risk and its changing trends are synthetically evaluated by calculating the adjacent connection number and analyzing the set pair potential. Using an actual overseas mining investment project as an example, the risk of overseas mining investment can be separated into five categories according to the risk field, and then the evaluation model is quantified and specific risk assessment results are obtained. Compared to the field investigation, the practicability and effectiveness of the evaluation method are illustrated. This new model combines static and dynamic factors and qualitative and quantitative information, which improves the reliability and accuracy of risk evaluation. Furthermore, this evaluation method can also be applied to other similar evaluations and has a certain scalability.

This paper proposes the development of a formation control algorithm of multiple acoustic underwater vehicles by employing the behaviour of autonomous mobile agents under a proposed pursuit. A robust pursuit is developed using the distributed consensus coordinated algorithm ensuring the transfer of information among the AUVs. The development of robust pursuit based on characteristics of multi-agent system is for solving the incomplete information capabilities in each agent such as asynchronous computation, decentralized data and no system global control. In unreliable and narrow banded underwater acoustic medium, the formation of AUVs based distributed coordinated consensus tracking can be accomplished under the constant or varying virtual leader’s velocity. Further, the study to achieve tracking based on virtual leader AUV’s velocity is extended to fixed and switching network topologies. Again for mild connectivity, an adjacency matrix is defined in such a way that an adaptive connectivity is ensured between the AUVs. The constant virtual leader vehicle velocity method based on consensus tracking is more robust to reduce inaccuracy because no accurate position and velocity measurements are required. Results were obtained using MATLAB and acquired outcomes are analysed for efficient formation control in presence of the underwater communication constraints.

‘Return to nature’ has become a buzzword in both scientific and public discourse. The growing interest in this phenomenon calls for the development of reliable tools for scientific research, for example the adaptation of various connectivity to nature (CN) scales developed by researchers from other cultural circles and other countries. The purpose of this study is to evaluate the psychometric properties of a Polish version of the AIMES scale for multidimensional assessment of CN as conceptualized by Ives et al. (2018). Validation studies were conducted using a survey administered on Prolific, an online platform, with a sample of 516 Poles (56% of them women) aged 18-66. The Polish version of AIMES showed high internal consistency (α = .92). Confirmatory factor analysis confirmed that the scale structure consists of a unified second-order factor with five first-order factors: attachment, identity, materialism, experiential, and spiritual. Relevance analysis showed significant positive associations of CN with perception of nature and silence, pro- environmental attitude and behaviour, psychological well-being, gratitude/awe, forgiveness, spirituality, extraversion, conscientiousness, and agreeableness, and a marginal positive association with openness to experience. The results strengthen the psychometric qualities of the AIMES scale, indicating its applicability to the study of CN in Polish contexts.

In Eurocode 5, the stiffness equation for bolted steel-wood-steel is stated as a function ofwood density and fastener diameter only. In this research, an experimental study on various configurations of tested bolted steel-wood-steel (SWS) connections has been undertaken to predict the initial stiffness of each connection. In order to validate the Eurocode 5 stiffness equation, tests on 50 timber specimens (40 glued laminated timbers and 10 laminated veneer lumbers (LVL)) with steel plates were undertaken. The number of bolts was kept similar and the connector diameter, timber thickness, and wood density were varied. The results obtained in the experimental tests are compared with those obtained from the Eurocode 5 stiffness equation. From the analysis, it is signified that the stiffness equation specified in Eurocode 5 for bolted SWS connections does not adequately predict the initial stiffness. The results from Eurocode 5 stiffness equation are very far from the experimental values. The ratio of stiffness equation to experimental results ranges from 3.48 to 4.20, with the average at 3.77, where the equation overpredicted the experimental stiffness value for the connection. There is a need to consider or incorporated other parameters such as geometric configurations in Eurocode 5 stiffness equation to improve the ratio with the experimental data.

The work concerns the influence of the method of numerical modelling of the connections of the roof truss and vaults with the walls of historic masonry objects structures on the local stress distribution in the walls. At the outset, the need to search for rational modelling was justified due to the large size of the calculation models and the erroneous results obtained with oversimplification of the model. Four methods of modelling the connections between the walls and roof truss and vaults were analysed. The first method was to describe the elements of walls and foundations as solid elements, the ribs of the vaults and the roof truss as beam elements, and the vaulting webs as shell elements. The remaining methods 2–4 describe the walls as shell elements. In places where the walls join with the roof truss and vaults, fictitious/fictional elements in the form of rigid horizontally-oriented shells were used in model No. 2. In model No. 3, fictitious rigid horizontally-oriented shell elements in addition to local rigid vertically-oriented shells were used, while in model No. 4, only fictitious rigid vertically-oriented shell elements with stepwise decreasing protrusions were introduced. The best solution in terms of local stress distribution turned out to be the description of connections with fictitious shell elements in the case of model No. 4. This approach slightly increases the number of unknowns, and makes the results of stresses in the connection areas realistic in relation to full modelling with solid finite elements.

The COVID-19 pandemic has exposed a specific paradox of contemporary urban planning. Cities that since the dawn of civilization have been considered the safest and most attractive human habitats turn into traps in a pandemic. For example New York, the most densely populated city in the United States, became the world’s epicentre of the pandemic in April 2020. Since 1992, successive teams governing the city stimulated pro-ecological planning strategies. From a neglected city, threatened with crime and plagued by terrorism, they turned it into a green metropolis, a symbol of a city of the 21st century. One of the most important planning and urban achievements was the successful revitalization of the post-industrial waterfront piers of Brooklyn and Queens. The rapid growth of bicycle transport stimulated by the planning authorities and supported by the construction of a network of bicycle routes along the main streets and coastal promenades should be noted as well. The aim of this study is to investigate the effects of the planning transformations in New York on the course of the COVID-19 pandemic, and to answer the question whether they made the city more resilient and safer.

Growing energy demands are expected to render existing energy resources insufficient. Solar energy faces challenges in terms of providing continuous and reliable power supply to consumers. However, it has become increasingly important to implement renewable energy (RE) and energy management (EM) systems to increase the supply of power, improve efficiency, and maintain the stability of energy systems. As such, this present study integrated energy storage (ES) devices; namely, batteries and direct current (DC) to DC converters; into energy systems that support battery operation and effectively manage power flow, especially during peak load demands. The proposed system also addresses low solar irradiation and sudden load change scenarios by enabling the battery to operate in a discharge state to supply power to the load. Conversely, when the demand matches or exceeds the available solar energy, the battery is charged using solar power. The proposed system highlights the significance of RE systems and EM strategies in meeting growing energy demands and ensuring a reliable supply of power during solar variability and fluctuating loads. A MATLAB® Simulink model was used to evaluate the integration of a 200 kW photovoltaic (PV) array with a 380 V grid and 150 kW battery. The loads, consisting of a 100 kW and a 150 kW unit, were parallel connected. The results indicated that boost and three-phase (3Ph) inverters can be used to successfully integrate PV systems to the power grid to supply alternating current (AC) power. The inclusion of a battery also addressed power shortages during periods of insufficient power generation and to store surplus power.

The aim of the article to assess the functioning of the NewConnect market over 10 years from the organizer’s and participants’ perspective. This helps to diagnose the most important organizational advantages and problems of the Polish MTF, determine further development prospects and propose potential changes to neutralize the negative factors. To illustrate the problem, a comprehensive analysis will be made of aggregated statistical data from 2007–2017, which show the changes and trends on this market, and additionally include the data comparing the current state of the NewConnect market with other alternative markets organized by European stock exchanges.

The conducted research does not allow to view the NewConnect market as an organizational success. The analysis identified a number of problems in the functioning of the Polish MTF, ranging from the inappropriate organization of the primary market, resulting in the admittance of too high a number of issuers of dubious credibility, to the consequences appearing on the secondary shares market. It does not give unambiguous grounds to expect positive prospects for the market development in the future. In order to stop unfavorable trends and to improve the issuers’ quality, a discussion on the regulations regarding issuers’ admission, i.e. the size of the minimum equity, IPO, capitalization and the issue price of the debuting company, should be initiated.

The grid integration of large-scale wind power will alter the dynamic characteristics of the original system and the power distribution among synchronous machines. Meanwhile, the interaction between wind turbines and synchronous machines will affect the damping oscillation characteristics of the system. The additional damping control of traditional synchronous generators provides an important means for wind turbines to enhance the damping characteristics of the system. To improve the low frequency oscillation characteristics of wind power grid-connected power systems, this paper adds a parallel virtual impedance link to the traditional damping controller and designs a DFIG-PSS-VI controller. In the designed controller, the turbine active power difference is chosen as the input signal based on residual analysis, and the output signal is fed back to the reactive power control loop to obtain the rotor voltage quadrature component. With DigSILENT/PowerFactory, the influence of the controller parameters is analyzed. In addition, based on different tie-line transmission powers, the impact of the controller on the low-frequency oscillation characteristics of the power system is examined through utilizing the characteristic root and time domain simulation analysis.

The disadvantages of the conventional model predictive current control method for the grid-connected converter (GCC) with an inductance-capacitance-inductance (LCL) filter are a large amount of calculation and poor parameter robustness. Once parameters of the model are mismatched, the control accuracy of model predictive control (MPC) will be reduced, which will seriously affect the power quality of the GCC. The article intuitively analyzes the sensitivity of parameter mismatch on the current predictive control of the conventional LCL-filtered GCC. In order to solve these issues, a model-free predictive current control (MFPCC) method for the LCL-filtered GCC is proposed in this paper. The contribution of this work is that a novel current predictive robust controller for the LCL-filtered GCC is designed based on the principle of the ultra-local model of a single input single output system. The proposed control method does not require using any model parameters in the controller, which can effectively suppress the disturbances of the uncertain parameter variations. Compared with conventional MPC, the proposed MFPCC has smaller current total harmonic distortion (THD). When the filter parameters are mismatched, the control error of the proposed method is smaller. Finally, a comparative experimental study is carried out on the platform of Typhoon and PE-Expert4 to verify the superiority and effectiveness of the proposed MFPCC method for the LCL-filtered GCC.

Grid-connected inverters are commonly used in systems of renewable energy to convert this energy source into AC power with parameters suitable for connection to the grid. In the normal operating conditions, the grid-connected inverters mainly generate active power to the grid. However, when a voltage sag or voltage imbalance occurs, the grid voltage imbalance in the conventional control methods causes negative sequence components and increases the output current magnitude of inverters. The increase of current can damage power semiconductor devices. This paper presents a strategy to limit the current magnitude of inverters under unbalanced grid voltage conditions. In this strategy, a multiple-complex-coefficient filter is used to eliminate the negative sequence voltage components. This method does not require any additional hardware. A three-phase gridconnected photovoltaic inverter system using a solar array of 20 kWp is also used for the survey. The effectiveness has been validated when comparing the simulation results on Matlab/Simulink of the proposed method with those of the conventional method.

While working on the oeuvre of P.F. Strawson (1919–2006), and especially on his metaphysics, I had a unique opportunity to exchange ideas with this eminent exponent of Oxford philosophy. Those exchanges, of which some have been reflected in private correspondence and in a published reply to one of my papers, were focussed on various interpretative questions. Three threads of those discussions seem especially pertinent for grasping the gist of Strawson’s philosophy and its general orientation. The first one concerned the nature of philosophical analysis, or to be more precise, the connective model of it, favoured by Strawson, and its relationship with the idea of concept presupposition. The second thread had to do with the position taken by the Oxford philosopher in the realism debate on three levels: semantic, epistemological, and metaphysical. Strawson made every effort to take a realist stand in this debate and avoid antirealism in any of its forms; however, his realism is in many respects very moderate and not so distant from antirealism. Similarly moderate was his stand in the traditional debate about universals, constituting the topic of the third thread of the exchanges with Strawson. He claimed that universals exist, but at the same time emphasized that they are objects of pure thought alone and as such do not form a part of the spatiotemporal world in which we live. One cannot also say much about the relation of exemplification in virtue of which universals manifest themselves in the world as particular instances. Presentation and elaboration of these three threads has led to the conclusion that although Strawson was a deeply systematic thinker, he avoided wide-ranging and ambitious statements and radical views. In characteristically minimalist way he dispelled some questions, and the ultimate resolution of many crucial and fundamental issues were for him choice and taking a particular attitude or stance.

To better extract feature maps from low-resolution (LR) images and recover high-frequency information in the high-resolution (HR) images in image super-resolution (SR), we propose in this paper a new SR algorithm based on a deep convolutional neural network (CNN). The network structure is composed of the feature extraction part and the reconstruction part. The extraction network extracts the feature maps of LR images and uses the sub-pixel convolutional neural network as the up-sampling operator. Skip connection, densely connected neural networks and feature map fusion are used to extract information from hierarchical feature maps at the end of the network, which can effectively reduce the dimension of the feature maps. In the reconstruction network, we add a 3×3 convolution layer based on the original sub-pixel convolution layer, which can allow the reconstruction network to have better nonlinear mapping ability. The experiments show that the algorithm results in a significant improvement in PSNR, SSIM, and human visual effects as compared with some state-of-the-art algorithms based on deep learning.

Experimental tests of steel unstiffened double side bolted end-plate joints have been presented. The main aim of the conducted tests was to check the behavior of joints in an accidental situation and possibility of creating secondary mechanism, i.e. catenary action in the scenario of column loss. Two types of end plate joints were tested: flush end-plate (FP) and extended end-plate (EP) with different thickness and different number of bolt rows in each. The tests were carried out on an isolated cross beam-column-beam type system until joint failure. During tests the available moment resistance and rotation capacity of bending joints and also values of tension forces in the beam were determined. The joints with extended end-plate have demonstrated higher bending and rotational capacity than flush end-plate. Significant deformation of column flanges, web and end plate were observed. The fracture of bolts was the failure mode of joints. Obtained results of axial force values in beam exceeded standard requirement what confirmed that the joints with unstiffened web column, flush or extended end-plate possess the ability of development the catenary action.

Soft-switching technologies can effectively solve the problem of switching losses caused by increasing switching frequency of grid-connected inverters. As a branch of soft-switching technologies, load-side resonant soft-switching is a hotspot for applications of high-frequency inverters, because it has the advantage of achieving soft-switching without using additional components. However, the traditional PI control strategy based on the linear model is prone to destabilization and non-robust dynamic performance when large signal perturbation occurs. In this paper, a novel Passivity-Based Control (PBC) method is proposed to improve the dynamic performance of load-side resonant soft-switching grid-connected inverter. Besides, the model based on the Port Controlled Hamiltonian (PCH) model of the soft switching inverter is carried out, and the passivity-based controller is designed based on the established model using the way of interconnection and damping assignmentpassivity based control (IDA-PBC). Both stable performance and dynamic performance of the load-side resonant soft-switching inverter can be improved over the whole operating range. Finally, a 750 W load-side resonant soft-switching inverter simulation model is built and the output performance is compared with the traditional PI control strategy under stable and dynamic conditions. The simulation results show that the proposed control strategy reduces the harmonic distortion rate and improves the quality of the output waveforms.

Block tearing is a failure mode of steel connections based on rupture of material. In this paper, a numerical model is developed to capture fracture initiation and progression until failure in steel angles connected by one leg using single row of bolts. It was realized using Gurson-Tvergaard-Needleman porous material model, which can accurately trace the behaviour of steel at plastic and ultimate range. Obtained results are validated on laboratory test results in global and local terms. Stress distribution along the failure paths in the gross and net area subjected to shear and tension was investigated for different geometrical arrangements of connections. Observation of rupture mechanisms allowed to compare the design procedures given in Eurocode 3 with connections behaviour. Results of analysis indicate that both plastic stress distribution in gross shear area and ultimate stress distribution in net shear area can limit block tearing resistance, which is consistent with the newest code provisions.