VGTU Journals (Vilnius Gediminas Technical University - Vilnius Tech)
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Aircraft hydraulic drive energy losses and operation delay associated with the pipeline and fitting connections
No full textTheoretical research on hydraulic processes occurring in aircraft hydraulic drives is presented in the studies. Installation of angular fitting connections in aircraft pipeline systems influences hydrodynamic processes and fluid flow characteristics analysed in the research. The provided analysis is based on a validated numerical model utilizing Navier–Stokes equations and the k-epsilon turbulence model. Fluid flow inside the aircraft hydraulic drive pipeline system was investigated with flow rates up to 100 l/min. A mesh independence study was conducted for numerical simulation of the fluid flow. The obtained results include fluid pressure drops, energy losses, and operational delays associated with fluid flow vortex formations at 45° and 90° angular fitting connections. Additionally, compared results from standard methods of calculation for angular fitting connections, including the equivalent length and equivalent length same shape methods
The significance of airport certification in the recovery process security of civil aviation of Ukraine
No full textThe main goal of this study is the need to solve the problems of safe and effective development of airport infrastructure, since the implementation of effective international and European standards, transformation and modernization of airport infrastructure is one of the directions of Ukraine’s work in the process of implementing international and European standards, as well as in the development of the UN Sustainable Development Goals. The authors used the method of analysis of the global reporting format to find out the requirements of the acts of international and European civil aviation organizations in the conditions of restoring the safety of civil aviation of Ukraine, compliance with standards and recommended practices regarding the certification of airport activities. Paths are defined recovery infrastructure of Ukrainian airports after the cessation of Russian military aggression, which caused horrible destruction, in particular, in the airport industry, the requirements for accreditation of airports, existing facilities on the territory of the airport were analyzed. The scientific novelty of the research lies in the fact that the authors carried out a thorough analysis of the requirements of international and European civil aviation organizations for airport activity, directions for certification of airports after the end of the war, which would contribute to the economic development of the state. The experience of Ukraine’s cooperation with international and European civil aviation organizations in the field of airport certification should contribute to the restoration of state’s capabilities for the safety of civil aviation flights
A comparative analysis of the aerodynamic performance of supersonic missiles with conical and ogive nose shapes
No full textThis paper presents a numerical study conducted to analyze the aerodynamic performance of supersonic missiles consisting of a cylindrical body and four flat-plate rear fins arranged uniformly, equipped with conical and ogive heads. Computational Fluid Dynamics (CFD) simulations were performed using the ANSYS Fluent 17.1 solver, along with the Gambit grid generation software. The objective was to compare the aerodynamic characteristics of these two head designs in terms of drag, lift, and stability at supersonic speeds. Various flow parameters, including Mach number and angle of attack, were investigated to comprehensively assess the performance of the missile configurations. The results indicate clear differences in the aerodynamic behavior of conical and ogive heads. Specifically, there was a 2–11 percent increase in the lift coefficient of the conical heads compared to the ogive heads, and an increase in the drag coefficient of both conical and ogive heads
Enabling technologies challenges of green Internet of Things (IoT) towards sustainable development in the era of Industry 4.0
No full textThe extensive adoption of the Internet of Things (IoT) has increased the carbon footprint on a large scale across the globe. To handle this challenge, scholars and policymakers are making efforts to propose novel energy-efficient solutions to provide a desirable environment for green-IoT (G-IoT). Additionally, further research is required to analyze the G-IoT-related challenges to elucidate the difficulties of its implementation for researchers. Moreover, the GIoT requirements have been considered in different network levels, namely software, hardware, architecture, communication. To present a comprehensive framework to identify the challenges of G-IoT, a survey using literature review and expert’s opinion is carried. Total 23 challenges are taken to evaluate and implement G-IoT technologies towards sustainable development achievements (SDA). Consequently, this article aims to rank and evaluate the challenges to implement the G-IoT towards the SDA. An integrated approach is proposed with stepwise weight assessment ratio analysis (SWARA) and additive ratio assessment (ARAS) under Pythagorean fuzzy sets. As a result, an machine-to-machine (M2M) standardization protocol with a weight value of 0.0508 has the first rank, followed by adaptation to natural energy sources with a weight value of 0.0479, information security and privacy protection with a weight value of 0.0469, and internet protocol version-6 (IPv6) for low-end devices with weight 0.0467. To validate the proposed method, sensitivity analysis and comparison using existing methods have been conducted.
First published online 30 March 202
Investigating the Internet-of-Things (IoT) risks for supply chain management using q-rung orthopair fuzzy-SWARA-ARAS framework
No full textModern “Supply Chains (SCs)” have recently been introduced as value networks of high complexity, and firms have focused on its efficiency as an important support for staying competitive in the market. Firms are currently capable of observing, tracking, and monitoring their products, activities, and processes throughout their value chain networks using new technologies, namely the “Internet of Things (IoT)”. Though, the influencing factors of IoT are highly complex and diverse, which result in the information-intensiveness of the SCs processes. This, in turn, leads to lots of barriers to SCs. In this paper, we evaluate and rank the IoT risks for “Supply Chain Management (SCM)” by utilizing “Stepwise Weight Assessment Ratio Analysis (SWARA)” and “Additive Ratio Assessment (ARAS)” under “q-Rung Orthopair Fuzzy Sets (q-ROFSs)”. A case study is presented for investigating the IoT risks for SCM in the q-ROFSs setting. Moreover, the obtained results were compared to those of some methods currently used in the literature. The outcomes of the study show that the security and privacy risks with a weight value of 0.0572 is the main IoT risk factor for the SCM and the organization-I with the utility degree 0.8208 is the best option with diverse IoT risks for SCM.
First published online 25 April 202
Internet of things-enabled tourism economic data analysis and supply chain modeling
No full textThe purpose is to cut the costs of Supply Chain enterprises in Ice-Snow Tourism (IST) and improve the intelligence and automation of Supply Chain Management (SCM). First, the spatial-temporal characteristics of economic data of the IST Supply Chain are analyzed based on the Internet of Things (IoT). Second, the annual Online Public Attention (OPA) data to IST in domestic cities and regions are collected. The quarterly concentration index and Gini coefficient are used to analyze their spatial and temporal characteristics. Then, the weighted fusion algorithm used for the Supply Chain scenario modeling is improved to solve data redundancy and improve information accuracy. Finally, the framework of the IST-oriented Supply Chain scenario ontology model is proposed. The experimental results show that Internet users give much attention to IST from 2011 to 2021. OPA to IST increased first and decreased and peaked in 2016. The final fusion value of the proposed data fusion algorithm is 20.0221, and that of the adaptive Weighted Average Method (WAM) is 20.0724. Thus, the proposed algorithm outperforms the adaptive WAM. The traditional scenario-based ontology model takes people as the center. In contrast, the Supply Chain scenario-based ontology model centers around product state and scenario. Therefore, the proposed Supply Chain scenario-based ontology model is entirely new. The proposed scenariobased ontology model using polymorphic IoT lays the foundation for developing an intelligent and automatic SCM. It has great practical significance in realizing efficient tourism industry management and SCM.
First published online 10 August 202
The impact of epidemics on green innovation: global analysis
No full textEpidemics and their resulting pandemics have become essential factors influencing economic development, financial stability, poverty, and ultimately a country’s innovation level, including green technology innovation. This research thus investigates epidemic events’ correlation to green innovation by operating with skewed panel data involving 134 countries from 1971 to 2018 and provides compelling proof that Epidemics have a detrimental effect on green innovation, not only for the current year but also for the next six years. We also show that the quality of institutions and financial development levels weaken epidemics’ detrimental effects on green innovation. Overall, the findings would draw particular attention from policymakers.
First published online 17 April 202
Green investment, energy efficiency, and economic growth: does economic freedom matter? Evidence from BRICS countries
No full textSustainable development goals, particularly number 7, clearly urges economies over the globe to multiple their efforts in order to improve efficiency. Although witnesses stressed out the importance of energy efficiency and claimed that when it is improved drastically, it triggers economic growth, however, the reported evidences to support the claim are mixed. In BRICS scenario, economies are experiencing the change from high-speed growth to high quality growth, due to which it is equally important to look into green investment as it is an essential tool to build high quality economic growth. Although green investment targets energy conservation as well as ecological deficit as it main goal. However, limited literature claims that it affects economic growth as well. Thus, the present study aims to assess green investment, energy efficiency, and economic growth (EG) and their impact on economic freedom index of the BRICS countries. Methods of Moments-Quantile-Regression (MMQR) approach is applied to explore the association between the understudy constructs in the time span of 2001–2020. Interestingly, it is revealed that green investment, energy efficiency and renewable energy are positively related with economic freedom index of the BRICS countries. With the evidences, the study proposes a conclusive remark to spur development across the countries
Indicators of non-performing loan: does efficiency matter?
No full textThe purpose of this study is to examine the impact of various factors on the level of non-performing loans (NPL) and, to determine the moderating role of efficiency on the relationship between different factors and NPL in China. The current study addressed four important factors to examine the role in relation to the NPL. These factors include; return on assets (ROA), return on equity (ROE), economic sustainability and political instability index. Furthermore, the moderating role of efficiency is addressed between these factors and NPL. Secondary data is used in this study to consider the empirical results. Secondary data related to ROA, ROE, economic sustainability and political instability index is collected from different sources. Consistent with the literature, we found significant effect of ROA, ROE, economic sustainability and political instability index on NPL. Banking sector of China is majorly influenced by these factors due to the effect on NPLs. Furthermore, the efficiency has contribution to the NPLs as moderating variable. Results of this study are helpful for the management of banking industry to resolve various issues related to NPLs
The role of organizational resilience in social, economic, environmental and human sustainability: evidence form Chinese FMCG sector
No full textDespite the extensive research on sustainability dimensions, the researcher has not completely addressed all the dimensions of sustainability. Most of the times, sustainability is considered as a whole variable, however, the work on separate dimensions is lacking in the literature. Particularly, human sustainability is rarely addressed by the previous studies. Additionally, various dimensions of sustainability such as social, economic, environmental and human is rarely tested in relation to the organizational resilience. Therefore, to fill this gap, this study considered to examine the role of organizational resilience in social sustainability, economic sustainability, environmental sustainability and human sustainability in a sample of FMCG employees. The study used non-probability snowball sampling to collect data from managerial level employees. Data analysis is carried out by using SPSS. Findings identified that; organizational resilience has influential role in various dimensions of sustainability. The focus of the policymakers on organizational resilience can increase the socio-economic and environmental sustainability. The operational efficiency can strengthen the relationship between organizational resilience and sustainability.
First published online 15 March 202