rss_2.0Engineering FeedSciendo RSS Feed for Engineeringhttps://www.sciendo.com/subject/ENhttps://www.sciendo.comEngineering Feedhttps://www.sciendo.com/subjectImages/Engineering.jpg700700Adoption of big data technologies in smart cities of the European Union: Analysis of the importance and performance of technological factorshttps://sciendo.com/article/10.2478/crdj-2021-0005<abstract> <title style='display:none'>Abstract</title> <p>The cities of the European Union are adopting big data technologies in their development towards a smart city. Given that big data technologies are complex and disruptive technologies, it is necessary to determine the importance of factors and their aspects for the adoption of big data technologies in cities. The aim of this paper is to identify the most important aspects of technological factors in the adoption of big data technologies in the cities of the European Union. In order to achieve the goal of the paper a survey was conducted on a sample of European Union cities, and on the collected data, an analysis of the map of importance and performance of factors for the adoption of big data technologies was conducted. The results of the research show that the aspects of absorption capacity and technological readiness of EU cities are of relatively high importance, but with low levels of performance in relation to organizational and environmental factors. The contribution of the paper consists of general guidelines for increasing the level of technological readiness and absorption capacity of cities in order to increase the success of the adoption of big data technologies in the cities of the European Union.</p> </abstract>ARTICLE2021-09-13T00:00:00.000+00:00Frost resistance of cement-sand and concrete beams during unilateral freezinghttps://sciendo.com/article/10.2478/crdj-2021-0009<abstract> <title style='display:none'>Abstract</title> <p>The work investigates changes in the beam structure under the action of local freezing, which leads to a change of the mechanical properties of the material and, consequently, of the beam structure. Two types of beam samples were used: from cement-sand mortar and from concrete. The work investigates the change in the development of deformations depending on the conditions of freezing of samples. The second accelerated method for assessing frost resistance was chosen according to DSTU B В.2.7-47-96. An accelerated method was chosen for assessing frost resistance at the temperature of -20 ±2 C°. After every five freeze-thaw cycles, the following changes were monitored: mass, water absorption, ultrasound transmission rate, damage coefficient, tensile bending strength, splitting strength, compressive strength, carbonization depth. The results showed that both in concrete and in mortar samples, the compressive strength after freezing was lower by 8% and 15% accordingly. The experimental results obtained confirm the assumptions made that the frost resistance of the material depends on the conditions of exposure of negative temperatures on products and structures and it can be used in a wider range of construction which will push regional development.</p> </abstract>ARTICLE2021-09-13T00:00:00.000+00:00Fine-grained Fiber Concrete on Mechanoactivated Portlandcementhttps://sciendo.com/article/10.2478/crdj-2021-0007<abstract> <title style='display:none'>Abstract</title> <p>This article is devoted to the study of the mechanical properties of fine-grained concrete used for flooring in industrial and civil buildings. Characterized by the well-known advantages (unlimited raw material base, manufacturability, high homogeneity), fine-grained concrete requires an increased consumption of cement to achieve the necessary mechanical characteristics - compressive strength, abrasion, impact resistance. An alternative to the known technological method is proposed an intensive separate technology (IST) for preparing fine-grained concrete mixtures using a high-speed mixer-activator in the presence of hydrophobized basalt fiber and a polycarboxylate superplasticizer Relaxol-Super PC. The use of IST leads to an increase in the strength of fine-grained concrete in compression by 1.9 times, impact resistance by a factor of 2, and a decrease in abrasion by 40... 50% in comparison with the control. The relevance of using the technology of monolithic floors for industrial and civil construction is due to a wide range of varieties of Portland cement, the grain composition of aggregates, as well as the simplicity of the technology for preparing a fine-grained concrete mixture.</p> </abstract>ARTICLE2021-09-13T00:00:00.000+00:00European Cohesion Policy and Evaluating the Impact of Evidence-Based Policyhttps://sciendo.com/article/10.2478/crdj-2021-0008<abstract> <title style='display:none'>Abstract</title> <p>In the 2014–2020 programming period, the cohesion policy focuses more on results and evaluation of programs based on facts. Due to the Commission policies, an expansion of cohesion policy counterfactual impact evaluation of programmes with new approaches can be expected in the future. In this paper, the focus is on the calculation of the impact of received European cohesion funds on the revenue of companies in Slovenian municipalities one/two years after the receipt of cohesion funds for the 2007–2013 period. Two development priorities that affect company revenue – Enterprise competitiveness and research excellence and Promoting entrepreneurship and adaptability are considered. The effect of the use of the European cohesion funds on company revenue in Slovenian municipalities is positive for 2009 and 2010 and negative for all other years examined. The results of the research can serve to policy-makers to reduce the economic, social and territorial disparities in less developed European countries and regions therefore reaching balanced regional development.</p> </abstract>ARTICLE2021-09-13T00:00:00.000+00:00Rethinking niche tourism: The example of backpackinghttps://sciendo.com/article/10.2478/crdj-2021-0004<abstract> <title style='display:none'>Abstract</title> <p>This conceptual paper re-evaluates the concept of niches in tourism markets. As many regions are now attempting to address niche markets in tourism as a development strategy, understanding of the dynamics of niche markets is crucial. Current approaches are often limited to seeing niche markets as simple subsectors of larger consumer markets. We argue for a broader view of market niches as forms of social rituals involving both consumers and producers with a mutual focus of attention. Based on the work of Randall Collins we examine how interaction rituals are produced and maintained, and how these are also reflected in niche markets, such as backpacking. We illustrate the how backpacking produces a mutual focus of attention and boundaries to outsiders, helping to sustain the niche over the longer term. This analysis has implications for producers hoping to tap into niche markets, as they too need to become part of the niche community.</p> </abstract>ARTICLE2021-09-13T00:00:00.000+00:00Durability of Modified Fiber Concrete for Rigid Pavementshttps://sciendo.com/article/10.2478/crdj-2021-0006<abstract> <title style='display:none'>Abstract</title> <p>Modified concretes and fiber concretes for rigid pavements have been investigated. Four-factor experiment was conducted. The amount of Portland cement, polypropylene fiber, metakaolin and polycarboxylate superplasticizer varied in the experiment. All mixtures had the same mobility S2.</p> <p>The active mineral additive metakaolin increases the compressive strength of concrete and its tensile strength in bending. The amount of metakaolin at the level of 15.20 kg/m<sup>3</sup> is rational. Due to a decrease in W/C with an increase in the amount of superplasticizer Coral ExpertSuid-5 to 0.9.1%, the compressive strength of concrete increases by 5.7 MPa, the tensile strength in bending increases by 0.5.0.6 MPa. Due to the introduction of polypropylene fiber, the tensile strength of concrete in bending increases by 0.6.0.9 MPa, the frost resistance of concrete increases by 50 cycles. Due to the use of a rational amount of superplasticizer and metakaolin, the frost resistance of concretes and fiber concretes concrete increases by 50-100 cycles. The use of a rational amount of modifiers and fiber reduces the abrasion of concretes by 40.45%.</p> <p>The developed modified fiber concretes of rigid pavements, depending on the amount of Portland cement, have compressive strength from 55 MPa to 70 MPa, tensile strength in bending from 8 MPa to 9.5 MPa, frost resistance from F350 to F450, abrasion from 0.30 to 0.40 g/cm<sup>2</sup>. Such strength, frost resistance and abrasion resistance allow the use of fiber concretes in pavements with the greatest load and ensures high durability of the material and corresponds to the directions and tasks of the state scientific and technical program “National Transport Strategy of Ukraine for the period up to 2030”</p> </abstract>ARTICLE2021-09-13T00:00:00.000+00:00Improvement of the Hammer Drill Performance (Algerian Quarries Conditions)https://sciendo.com/article/10.2478/auseme-2020-0006<abstract><title style='display:none'>Abstract</title><p>The factors which influence the performance characteristics of a hammer drill are examined; drilling data are analyzed to determine these factors. Methods for selecting the appropriate drilling are also highlighted. Two models are used in order to compare optimal drilling parameters. The main one is the machine output.</p></abstract>ARTICLE2020-12-31T00:00:00.000+00:00Thermosolutal Convection in a Porous Medium Cavity Subjected to Heat and Mass Flux: A Discrete Fracture Effecthttps://sciendo.com/article/10.2478/auseme-2020-0007<abstract><title style='display:none'>Abstract</title><p>Species separation in heterogeneous porous media is a field of interest of many industrial activities. In our investigation, the effect of a single discrete fracture on the thermosolutal convection coupled with the Soret effect have been analyzed. The main results show that the fracture can greatly affect the behavior of the thermogravitational flow and might play a positive role to the separation caused by the Soret effect. Furthermore, the fracture tilted to the cold wall causes a large separation compared to the one tilted to the hot wall with the same angle. Therefore, the separation process could be greatly improved.</p></abstract>ARTICLE2020-12-31T00:00:00.000+00:00The Impact of Integrated Maintenance Actions Optimization on Strategic Machines Lifetimehttps://sciendo.com/article/10.2478/auseme-2020-0004<abstract><title style='display:none'>Abstract</title><p>This article is based on the quantitative study of reliability, maintainability, availability (<italic>RMA</italic>), on the Pareto diagram (<italic>ABC</italic>) and on the analysis of the failure modes and their impact on criticality (<italic>FMECA</italic>). The developed approach aims, at first, implementing two optimization procedures (code development, Simulink modelling in MATLAB) and using two methods (graphical, analytic) of the Weibull parameters. The results obtained via code (which is based on the Weibull graph method of two parameters) are a bit divergent. The evaluation criteria are rather far from that of the model (which is based on the maximum likelihood of three-parameter Weibull distribution). This will allow to locate the critical elements, and to determine the systematic preventive time of replacements. An application case validates the proposed study objective.</p></abstract>ARTICLE2020-12-31T00:00:00.000+00:00Corrosion Resistance of Coatings Produced by Spraying Powders Under a Laser Beam in a Saline Environment NaCl 3% by the Electrochemical Methodhttps://sciendo.com/article/10.2478/auseme-2020-0008<abstract><title style='display:none'>Abstract</title><p>The manuscript focuses on the study of corrosion resistance in NaCl medium of a 304L type stainless steel after application of protective nickel-based and cobalt-based coatings produced by powder spraying under a continuous CO<sub>2</sub> laser (10.6 µm wavelength) beam. Using polarization and electrochemical impedance spectroscopy methods, the results found confirm that metallic coatings produced under high energy beams offer excellent protection up to an efficiency of <italic>E</italic> = 98.12% in aggressive environments with salinity to 3%.</p></abstract>ARTICLE2020-12-31T00:00:00.000+00:00Study of Reliability in a Repairable System by Markov Chainshttps://sciendo.com/article/10.2478/auseme-2020-0005<abstract><title style='display:none'>Abstract</title><p>In the industrial sector, maintenance of production facilities plays an important role to carry out production by increasing the reliability and availability of the production process. Predictive maintenance strategy seems adequate to anticipate the failure and degradation of the state of such equipment. A reliability study is needed to quantify indicators to describe the functioning of any system over time. In this paper, we present the results of a stochastic modeling conducted on the analysis of the availability of motor-pump system, installed in a cooling circuit in an industrial complex. The equipment considered in this study is composed of four subsystems. The proposed model is a dynamic Markovian approach, for the purpose of a comparison with the analytical calculation in terms of the indicators’ evaluation of the dependability of the studied system, including instant availability. The different states of the system components and the transition functions between these states have also been characterized. The results of availability obtained by the model are well correlated with those calculated analytically, confirming that the proposed model is very powerful, it will help predict the future states of the system, in order to predict any necessary preventive maintenance actions.</p></abstract>ARTICLE2020-12-31T00:00:00.000+00:00Generation of PWM Based on Simple Relay Feedback Systemshttps://sciendo.com/article/10.2478/auseme-2020-0002<abstract><title style='display:none'>Abstract</title><p>This paper is concerned with the analysis of the tracking capability of Relay Feedback Control Systems (RFCS). The envisioned application is the generation of Pulse-Width-Modulation (PWM) with variable duty-cycle and frequency known also as Duty-Cycle Modulation. In general, two main issues have to be solved with RFCS when used for regulation and tracking. The first issue concerns the determination of autonomous self-oscillations which are generated by the closed loop. The second issue concerns the determination of the relationship between the reference and the output signals. However, if the first issue has beneficiated from different approaches and has been solved particularly in case of zero reference signal, the second issue has got insufficient theoretical results because of mathematical difficulties for obtaining analytical expressions. Considering these reasons, a deep analysis of RFCS constituted of a hysteretic relay and linear systems of first order is presented. Analytical expressions relating self-oscillations and output mean values with respect to the reference signals are obtained. The analysis of these relationships led to infer some conditions under which the relay feedback control can generate commands for regulating and tracking reference signals. It highlights also the key role played by the hysteresis band width for applications based on RFCS. Our analysis, exploiting the analytical expressions, can be used to achieve a complete design for power converters. Moreover, simulation and experiments have confirmed our results.</p></abstract>ARTICLE2020-12-31T00:00:00.000+00:00A New Model of Dynamic Logic Circuit with NMOS based Keeperhttps://sciendo.com/article/10.2478/auseme-2020-0001<abstract><title style='display:none'>Abstract</title><p>Dynamic logic circuits are widely popular due to a smaller number of transistors and consume less area. But the time to switch between logics is higher due to higher contention value. A new model of the logic using nMOS based keeper circuit is proposed and the performance is evaluated using Cadence tools. Comparative results demonstrate the suitability and competency of the proposed circuit.</p></abstract>ARTICLE2020-12-31T00:00:00.000+00:00Model-Based Control Strategy for Autonomous Vehicle Path Tracking Taskhttps://sciendo.com/article/10.2478/auseme-2020-0003<abstract><title style='display:none'>Abstract</title><p>Despite the advanced technologies used in recent years, the lack of robust systems still exists. The automated steering system is a critical and complex task in the domain of the autonomous vehicle’s applications. This paper is a part of project that deals with model-based control strategy as one of the most common control strategies. The main objective is to present the implementations of Model Predictive Control (MPC) for an autonomous vehicle steering system in regards to trajectory tracking application. The obtained results are analysed and the efficiency of the use of MPC controller were discussed based on its behaviour and performance.</p></abstract>ARTICLE2020-12-31T00:00:00.000+00:00Network analysis of interconnections between theoretical concepts associated with principal–agent theory concerning construction projectshttps://sciendo.com/article/10.2478/otmcj-2021-0025<abstract> <title style='display:none'>Abstract</title> <p>Communication risks and asymmetric information among project participants are often associated with poor performance in construction projects. Communication and coordination are prominent issues in recent research on construction management, with little actual theoretical foundation. The purpose of this study is to investigate the extent to which principal–agent (P–A) theory and its implications are used in construction management research. In the archives of the top seven construction management journals, 148 scientific papers mentioning P–A theory were found. The keywords were analysed to determine the connections between them. Network analysis (NA) of the interconnected keywords was used to illustrate the most common relations between P–A theory and construction management. The findings of this study indicate that the most important elements associated with P–A theory in construction management are contracts, governance, partnership, transaction costs, information systems, incentives, risk management, and trust. However, some keywords are often used without considering related theoretical concepts. This study introduces a new perspective on P–A theory research in the field of construction management.</p> </abstract>ARTICLE2021-08-24T00:00:00.000+00:00Leadership skills, stakeholder management and execution of fibre-optic infrastructure: intervening influence of government policyhttps://sciendo.com/article/10.2478/otmcj-2020-0014<abstract> <title style='display:none'>Abstract</title> <p>Communication technology has drastically evolved in the last 10 years across the globe. With increased demand for data and voice traffic, fibre-optic network is preferred to transmit high-speed broadband. Nonetheless, fibre-optic infrastructure involves huge construction challenges and continues to fail because of ineffective leadership, stakeholder management and government policies. The main purpose of this study was to investigate how government policy intervenes on the joint influence of leadership skills and stakeholder management on execution of fibre-optic infrastructure in Nairobi County, Kenya. This study adopted the pragmatism paradigm approach, with a cross-sectional survey design. Census was used to select 187 respondents from a target population of 187 functional staff in fibre-optic infrastructure departments. A questionnaire was used to collect quantitative data while an interview guide was used to collect qualitative data. Statistical analysis techniques were used to analyse the data. It was demonstrated that government policy has a significant intervening influence on the joint influence of leadership skills and stakeholder management on execution of fibre-optic infrastructure. Therefore, governments should come up with policies to guide and regulate execution of fibre-optic infrastructure, review building code to allow for fibre-optic services in new buildings, develop right of way conduits and establish a centrally coordinated authority to facilitate time-bound issuance of permits and related services. It was suggested that similar studies should be carried out in other countries and target vendors and contractors engaged in supply of equipment and construction of fibre-optic infrastructure.</p> </abstract>ARTICLE2021-07-31T00:00:00.000+00:00Providing a framework for optimizing a mixing design of reactive powder concrete (RPC)https://sciendo.com/article/10.2478/otmcj-2020-0024<abstract> <title style='display:none'>Abstract</title> <p>Suitable distribution of particles and the presence of hydration lead to the improved compressive performance and optimum (even reduced) cost in the production of reactive powder concrete (RPC). This study was conducted to obtain a better understanding of RPC and analyze the behavior of modified RPC (MRPC) using the properties of surface resistivity, water penetration, compressive strength, and modulus of elasticity, apart from the cost. The present study was carried out to investigate how to optimize the size and diversity of the aggregate in order to increase the applications and reduce the costs. The options were selected from among the 12 alternatives classified during the construction stages. According to the six weighting parameters used for comparing with the sample, the derived framework can be described as a mixing design for RPC. Five weighting criteria were considered with values of one of the five criteria missing, and in one case, all criteria were taken with equal weights. For the final analysis, the Expert Choice software was used to create a framework for the optimal mix design of RPC and MRPC. The MRPC mixing designs showed good results, with very slight differences compared to RPC. In many cases, MRPC can be used instead of RPC.</p> </abstract>ARTICLE2021-07-31T00:00:00.000+00:00Impact of management practices on construction productivity in Indian building construction projects: an empirical studyhttps://sciendo.com/article/10.2478/otmcj-2021-0007<abstract> <title style='display:none'>Abstract</title> <p>The objective of this study is to analyse the impact of management practices on the productivity of building construction projects in India. The methodology adopted for this study is to identify and analyse the management practice attributes from the literature review and expert focus group interviews. The identified attributes were analysed and priorities using relative weight were given by the respondents. The collected data were further analysed using SPSS 21 software. The quantitative research methodology was adopted to analyse the collected data and the following tools and techniques were applied to the data: reliability analysis to check the consistency of data collected for this study and relative importance index (RII) to prioritise and rank the attributes based on the weighted average score given by the respondents. The findings of this study concluded that coordination between all stakeholders, ability to handle the crisis by the project managers, social skills of key team managers, timely payment of completed works and design capability and frequent design changes are the most significant attributes of management practice, affecting construction productivity and having a rating on the RII of 0.91, 0.90, 0.88, 0.87 and 0.87.</p> </abstract>ARTICLE2021-07-25T00:00:00.000+00:00On-site factories to support lean principles and industrialized constructionhttps://sciendo.com/article/10.2478/otmcj-2021-0004<abstract> <title style='display:none'>Abstract</title> <sec><title style='display:none'>Purpose</title> <p>The purpose of this study is to investigate the use of on-site factories that combine the strengths of both prefabrication techniques and a traditional work environment to support lean principles and promote industrialized construction for on-site operations.</p> </sec> <sec><title style='display:none'>Design/methodology/approach</title> <p>Based on the principles of lean construction and design for manufacturing and assembly (DfMA), discrete-event simulation is used to evaluate different arrangements and configurations of an on-site factory for the prefabrication of structural insulated panels (SIPs).</p> </sec> <sec><title style='display:none'>Findings</title> <p>The proposed on-site factory provided a feasible way to promote lean and industrialized construction principles. Also, these types of factories are particularly relevant for projects in remote areas that do not have sufficient infrastructure. Further, it is also a good solution for strengthening the local economy by using local labor and suppliers, hence assisting in the creation of a socially responsible framework.</p> </sec> <sec><title style='display:none'>Originality/value</title> <p>This study presents the design of an on-site factory for the prefabrication of SIPs. This type of on-site assembly supports not only lean principles but also promotes social responsibility by capitalizing on local labor. This approach could be particularly interesting for construction companies in developing countries or working in a project with limited infrastructure.</p> </sec> </abstract>ARTICLE2021-03-21T00:00:00.000+00:00A study of project managers’ choice on key methods, tools and techniques in managing engineering projectshttps://sciendo.com/article/10.2478/otmcj-2021-0002<abstract> <title style='display:none'>Abstract</title> <p>There is no doubt that each project manager uses different methodologies, methods, tools and techniques (MMTTs) while dealing with constant pressure to deliver results in a complex and changing environment, where complexity and stakeholders’ expectations are continually growing. This article presents results from the study about project managers’ choice on artefacts that they frequently use in their regular work. This study was conducted within the context of selected environment (one country and one sector of engineering projects), but designed methodology and results might also be significant for a wider audience. The results were based on the feedback that were received from 31 project management (PM) professionals gathered in the form of a structured questionnaire, followed by an interview with three PM experts for validation. The results confirmed a variety of PM artefacts in use and provided their ranking by perceived usefulness. The additional results indicated correlation between PM success and usage of MMTTs, as perceived by project managers. This study also resulted in several interesting findings, such as popularity and usefulness of artefacts, rigidity of PM processes, and maturity of PM organizations, about the topic. Despite of rather small sample taken from one country's environment, the results could serve as a solid information for moving ahead, while considering the significance of PM artefacts, as well as for their further development. The key findings are also messages to PM professionals to consider whether they use available and appropriate PM artefacts and is there a room for more efficient and effective usage.</p> </abstract>ARTICLE2021-03-21T00:00:00.000+00:00en-us-1