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Strength study of the load-bearing wall of a frame building.
No full textThe growing problem of climate change and stricter environmental requirements are driving the construction sector to think and look for sustainable, environmentally friendly, renewable and low-waste solutions. One such option is timber frame buildings. The aim of this master thesis is to investigate the strength of the load-bearing walls of a timber frame building. The first part of the thesis deals with the interpretations of Lithuanian and foreign scientists concerning the concept of frame buildings and the essential structural solutions. It looks at environmentally friendly options for the insulation of framed building structures using rapidly renewable alternative building materials, agricultural production and recycling by-products. It describes the key stages of the construction of a framed building and identifies the key technologies and optimization of the construction process for framed buildings. Research carried out by scientists on the strength properties and functions of load-bearing walls of buildings is examined. The second part of the thesis presents the design methodology of the framed panel, describing the loads acting on the wall of the framed panel, presenting the eccentrically compressible elements and their compliance with the technical building regulations in Lithuania. The third part presents the research model, the Wall Element Strength Study, which is developed using SolidWorks software. In order to assess the strength, stiffness and durability of the framed building, an analysis of the strength of the load-bearing wall elements of the framed building analysis is carried out and special calculations of the eccentrically tensile and compressive elements are performed. The study starts with an assessment of the loads acting on the load-bearing wall panel, the selection of the specific physical and mechanical properties of the framing panel elements, and the modelling of the load-bearing wall frame elements in SolidWorks software package. The strength analysis of the framed building wall is based on the evaluation of the obtained calculation results for a set of selected and modifiable parameters. The parameters to be varied and evaluated are these: the dependence of the strength and stiffness of the wall on the position of the panel joints, the thickness of the panels, the height of the panel thickness, the spacing of the struts and the height of the strut cross-section
Factors of the work efficiency of digital nomads.
No full textIn a changing world, with increasing mobility and digitalisation, employees’ perception of the traditional working model is changing and organisations are under pressure to become more dynamic and flexible. The COVID-19 pandemic has also has significantly impacted employees’ perceptions of an attractive working model. It has contributed to the effect that companies in the post-pandemic period have started to offer more freedom and flexibility to employees in order to adapt to emerging trends. When people hear “flexible working”, they often associate it with teleworking, but this is only one of the possible options. Another form of flexible working that is rapidly gaining popularity in today’s labour market is the digital nomad lifestyle. Digital nomads are individuals who are not tied to a specific location and use technology to perform their work remotely, choosing locations based on personal preferences. As the digital nomad model of working becomes more and more popular in society, the issue of efficiency is becoming increasingly important. Efficiency is typically a key aspiration, as it contributes to successful outcomes, cost reduction, and higher-quality work. The literature relates the determinants of employee effectiveness to the motives for choosing a work pattern and to the personal needs of the individual. It also focuses on factors such as mobility, the impact of technology, time management and planning skills, self-discipline, and a sense of community belonging. The aim of this Thesis was to explore the determinants of digital nomad performance through semi-structured interviews. The participants were current and former digital nomads who agreed to share their personal experiences. The findings of the study reveal that digital nomads face disruptions that affect their performance. To ensure their efficiency, they make use of some of the opportunities offered by the digital nomad working model, such as mobility or time planning and management. Some digital nomads use specific technologies, develop self-management skills and stay in touch with peers. The study revealed that the factors that make digital nomads effective, as well as the individual needs of digital nomads, may vary depending on the individual, his/her value system and the surrounding environment. This Thesis discusses and analyses the key factors of work effectiveness that are relevant to most digital nomads
Factors determining the retention of generation Z employees in the logistics.
No full textThe analysis of the literature helped to understand that the problem of employee retention is still relevant and will be relevant among employees in the logistics sector. Various studies have shown that it is more profitable to retain an employee rather than to replace him, since the cost of training and recruiting can vary from half to double the salary of the former employee. Despite the financial losses that organizations may experience, they also face the loss of important knowledge. The outgoing employee takes with him the acquired knowledge, which he can apply in another company, thereby helping competitors. Generation Z employees by 2030 will occupy an increasing share of the labor market, and older workers in the logistics sector will leave organizations. Such a situation will encourage employers to look for measures to help attract and retain Generation Z employees. This generation will soon be the one to make up the majority of the organization's workforce and lead it forward. The aim of the project. To identify the retention factors of generation Z employees in the logistics sector. Project objectives: 1. To reveal the issue of retaining generation Z employees in the logistics sector. 2. To prepare a theoretical model of the retention factors of generation Z employees. 3. To investigate the retention factors of generation Z employees in the logistics sector. 4. Based on the empirical research results, prepare recommendations for the retention of employees of the Z generation in the logistics sector. The main results of the project. After analyzing the scientific literature, an initial theoretical model of retention factors of Generation Z employees was prepared. It consists of seven groups of theoretically analyzed retention factors - nature of work, culture and company policies, communication and relations with managers, colleagues, career, work organizational factors, compensation, technology - and employee retention based on variables such as performance rates and assessment of intention to leave the job. The results of the empirical study revealed that there is a statistically significant relationship between groups of retention and employee retention factors, such as culture and company policy, communication and relations with managers/colleagues, career, work organization factors, compensation and technology. After checking the theoretical model of the retention factors of generation Z employees, it is confirmed that all the retention factors discussed in the literature can influence the desire of generation Z employees to leave the organization, with the exception of job nature factors. The results obtained during the analysis of the empirical study showed that the nature of work factor has no relationship with retention, although the literature has widely discussed the basis of work factors influencing employee retention
Improved defect sizing in adhesive joints through feature-based data fusion /
No full textThe current study focuses on the examination of adhesive-bonded materials, comprising different type of flaws like brass inclusions and delamination, through the application of ultrasound and X-ray non-destructive testing (NDT) techniques. The findings from both ultrasound and X-ray inspection were used to extract unique features, contributing to a more comprehensive understanding of the distinct characteristics demonstrated by each method. Several distinct features like absolute time of flight difference, peak-to-peak amplitude, variation coefficient in time and frequency domain, mean value of amplitude in frequency domain, and absolute energy were extracted from ultrasound testing results. Similarly, features like maximum amplitude, features from accelerated segment test, dilation, watershed segmentation, wiener deconvolution, and morphological gradient extracted from X-ray data underwent fusion. Different fusion techniques were applied to combine these features into a unified data set. A quantitative evaluation was performed for the individual features and their corresponding fused features from the ultrasound and X-ray results. A systematic analysis was conducted to quantify the improvement in defect sizing within the individual features and fused features from both the X-ray and ultrasonic investigations. The minimum absolute error of 0.02 mm was achieved with average fusion of absolute energy at 2nd interface and X-ray dilate features. This research not only delves into the diverse capabilities of ultrasonic and X-ray NDT methods in identifying flaws but also emphasizes the synergistic advantages arising from the integration of their distinct features. The qualitative study of defect estimation using the proposed fusion methods demonstrate that the distinctive fusion approaches significantly highlight the complimentary benefits of ultrasound and X-ray non-destructive testing methods, resulting in a quantifiable improvement in probability of defect detection
Assessment of the impact of external environmental factors on the development of the wind energy sector.
No full textThe Master's thesis titled "Assessment of the Impact of External Environmental Factors on the Development of the Wind Energy Sector" analyzes economic, technological, political-legal, socio-cultural, and natural factors influencing the development of the wind energy sector. The first part of the thesis discusses the evolution of the wind energy sector, from traditional windmills to modern wind farms, examines technological advancements, and considers geopolitical factors such as energy security and the reduction of dependence on fossil fuels. The second part presents the concept of external environmental factors, their classification, and analysis methods, including PEST analysis, correlation analysis, and the Granger causality test. The third part introduces empirical research results and provides conclusions. The aim of the thesis is to evaluate the impact of external environmental factors on the development of the wind energy sector. The objectives are: 1.To review the trends and challenges of wind energy sector development in European countries and substantiate the relevance of assessing the impact of external environmental factors on the wind energy sector. 2.To theoretically substantiate the relationship between external environmental factors and the development of the wind energy sector and to identify external environmental assessment methods from a theoretical perspective. 3.To develop a research methodology for assessing the impact of external environmental factors on the development of the wind energy sector. 4.To conduct research on the impact of external environmental factors on the development of the Lithuanian wind energy sector
Assessing the competitiveness of Lithuanian inbound yourism in the context of economic shocks.
No full textThis paper analyses scientific sources in order to provide an overview of the competitiveness of Lithuania's inbound tourism sector in the context of economic shocks, highlighting key challenges and opportunities. It examines the concepts of economic shocks, their impact on the tourism sector, methods of assessing the sector's competitiveness and factors determining the sector's resilience to crises. Statistical analysis, data systematisation, application of competitiveness models and econometric methods are applied to achieve the objective of the paper. The results of the study revealed that the Lithuanian inbound tourism sector is vulnerable to economic shocks, but has certain strengths, such as cultural and natural potential. The main problems relate to limited infrastructure, lack of international visibility and use of technology. However, the analysis shows that well implemented strategies such as promoting digitisation, targeted marketing campaigns and improving infrastructure can make a significant contribution to the competitiveness of the sector. The study makes recommendations aimed at strengthening the competitiveness of Lithuania's inbound tourism sector. It suggests increasing investment in infrastructure, promoting digitisation and technology, targeted marketing campaigns and public-private cooperation. The implementation of the recommendations would contribute to increasing the sector's resilience to crises and strengthening its competitiveness in the global market
Fusing LiDAR and photogrammetry for accurate 3D data: a hybrid approach /
No full textThe fusion of LiDAR and photogrammetry point clouds is a necessary advancement in 3D-modeling, enabling more comprehensive and accurate representations of physical environments. The main contribution of this paper is the development of an innovative fusion system that combines classical algorithms, such as Structure from Motion (SfM), with advanced machine learning techniques, like Coherent Point Drift (CPD) and Feature-Metric Registration (FMR), to improve point cloud alignment and fusion. Experimental results, using a custom dataset of real-world scenes, demonstrate that the hybrid fusion method achieves an average error of less than 5% in the measurements of small reconstructed objects, with large objects showing less than 2% deviation from real sizes. The fusion process significantly improved structural continuity, reducing artifacts like edge misalignments. The k-nearest neighbors (kNN) analysis showed high reconstruction accuracy for the hybrid approach, demonstrating that the hybrid fusion system, particularly when combining machine learning-based refinement with traditional alignment methods, provides a notable advancement in both geometric accuracy and computational efficiency for real-time 3D-modeling applications
Alkali-activated binder of municipal solid waste incineration bottom ash at lower pH levels /
No full textThis paper focuses on the alkaline activation of municipal waste incineration (MSWI) bottom ash to create a dense, non-porous composite structure. Normally, high pH solutions are used to activate MSWI bottom ash, but this has the side effect of creating residual effects in the bottom ash. Due to the uniqueness of the incineration process, the bottom ash retains metallic aluminum, which reacts with the alkali to produce hydrogen gas, which forms a porous structure in the sample during the hardening of the composite. This study demonstrates a method of eliminating this effect by lowering the pH of the alkaline activator below 12.5. An alkali-activated binder was prepared from ground MSWI bottom ash as a precursor and a triple alkali activator: NaOH solution, soluble glass (SG) and silica gel waste (SW). The highest compressive strengths of about 20 MPa were achieved for alkali-activated MSWI bottom ash with triple alkali activators such as sodium hydroxide, soluble glass and silica gel waste
Evaluation of conditions for self-healing of additively manufactured polymer composites with continuous carbon fiber reinforcement /
No full textAdditive manufacturing (AM) is one of the most frequently used technologies to produce complex configuration products. Moreover, AM is very well known as a technology which is characterized by a low amount of generated waste and the potential to be called zero-waste technology. As is known, there are seven main groups of technologies described in the ISO/ASTM 52900 standard that allow the use of very different materials from polymers to metals, ceramics, and composites. However, the increased utilization of additively manufactured composites for different applications requires a deeper analysis of production processes and materials’ characteristics. Various AM technologies can be used to produce complex composite structures reinforced with short fibers; however, only material extrusion (MEX)-based technology is used for the production of composites reinforced with continuous fibers (CFs). At this time, five different methods exist to produce CF-reinforced composite structures. This study focuses on co-extrusion with the towpreg method. Because of the complexity and layer-by-layer nature of the process, defects can occur during production, such as poor interlayer adhesion, increased porosity, insufficient impregnation, and others. To eliminate or minimize defects’ influence on mechanical properties and structural integrity of additively manufactured structures, a hypothesis was proposed involving heat treatment. Carbon fiber’s conductive properties can be used to heal the composite structures, by heating them up through the application of electric current. In this research article, an experimental evaluation of conditions for additively manufactured composites with continuous carbon fiber reinforcement for self-healing processes is presented. Mechanical testing was conducted to check the influence of heat treatment on the flexural properties of the composite samples
Evaporation and ignition of isolated fuel drops in an oxidizing environment: analytical study based on Varshavskii’s ‘Diffusion theory’ /
No full textVarshavskii’s ‘Diffusion Theory’, less investigated due to its limited international visibility, can offer one of the simplest and, on the other hand, high-accuracy methods for evaluating the ignition delay of fossil fuel and biofuel droplets, including their blend. In this study, experimental pre-tests were conducted to determine pre-existing subject knowledge on stationary droplet combustion at ambient pressure and temperatures varying from 935 to 1010 K followed by simulation of droplet ignition times. The test fuels were mineral diesel (DF), RME and a 20% RME blend with DF. Simulations were performed for isobaric conditions. Using the detailed transport model and detailed chemical kinetics, the necessary rearrangements were made for the governing equations to meet the criteria for modern fuels (biodiesel, diesel, and blend). The influence of different physical parameters, such as droplet radius, or initial conditions, on the ignition delay time was investigated. The high sensitivity of the proposed methodology to experimental results was substantiated