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Damping of Dry Sand in Resonant Column-Torsional Simple Shear Device

Majd Ahmad R. P. Ray

Publication Name: Sustainability Switzerland

Publication Date: 2023-07-01

Volume: 15

Issue: 14

Page Range: Unknown

Description:

The damping ratio values of three different Danube sands were measured in the Resonant Column-Torsional Simple Shear device (RC-TOSS). The distinctive configuration of the RC-TOSS device employed in this investigation enabled the performance of both tests using a single sample. This research estimates and compares the damping ratio values measured with three distinct methods (two of which are in the RC test): The Free Vibration Decay (FVD), the Steady-State Vibration (SSV) methods, and the method of calculating the damping ratio from the hysteretic loops generated in the TOSS test. Both dense and loose samples were tested up to a peak-to-peak amplitude shear strain of 1%. The device provides measurements over a wide range of shear strain amplitudes. The results support the employment of the SSV methods at low strains (below 0.005%), while the FVD method gives a better estimate at higher strains (above 0.03%). The two methods and the TOSS results are in agreement with each other between 0.005% and 0.03%. The effect of the number of cycles on the damping ratio was investigated where a significant decrease was observed in the damping ratio with an increasing number of cycles. A parameter is introduced to describe the rate of this decrease, which should be considered during the structural design to reduce maintenance and life-cycle costs and enhance sustainability.

Open Access: Yes

DOI: 10.3390/su151411060

Lack of Collaboration on the CEP Market and the Underlying Reasons—A Systematic Literature Review

Edit Süle László Buics Csilla Bartucz

Publication Name: Sustainability Switzerland

Publication Date: 2023-07-01

Volume: 15

Issue: 13

Page Range: Unknown

Description:

The scientific community has been addressing the topic of last-mile delivery for years. To improve parcel delivery efficiency, a variety of different technologies have been created. Over the past 15 years, the focus has shifted from the operational efficiency of the individual organization to restoring sustainability and making cities more livable. As a result of the increased environmental burden, governments are enacting a growing number of restrictive measures, which will intensify economic challenges. To remain competitive, more cost-effective solutions are required. The goal of this article is to examine the significance of collaboration between CEP partners based on scientific interest, with the help of a systematic literature review. This examination is important since, despite the fact that working together with other service providers and competitors could be a favorable option for last mile suppliers looking to improve their efficiency, results show little interest in this approach. Although this strategy appears straightforward due to the potential financial and environmental benefits, there are only a few examples of collaboration in the field of last mile parcel delivery according to the results of the review. Since cooperation seems to be an inevitable operating model of the CEP market in the future, it is of utmost importance for scientific research to investigate the factors hindering the development of cooperation.

Open Access: Yes

DOI: 10.3390/su151310361

Synthesis of multiperiod heat exchanger networks: n-best networks with variable approach temperature

Ákos Orosz Rozália Lakner Bing Shen How Ferenc Friedler

Publication Name: Thermal Science and Engineering Progress

Publication Date: 2023-07-01

Volume: 42

Issue: Unknown

Page Range: Unknown

Description:

In industrial processes, the stream parameters of the heat exchanger network (HEN) synthesis problem can vary during different periods. As a result of the change in inlet and outlet temperatures and the flow rates of the streams, the optimal HEN and the optimal heat transfer areas of the heat exchangers can be different in each period. In our previous work, the standard HEN synthesis for minimum utility consumption was extended to consider varying stream parameters, where bypasses at the heat exchangers are used to ensure the exit streams meet the expected outlet temperatures. This requires optimization of the total annualized cost based on the maximal heat transfer areas of the heat exchangers for each period. Minimum approach temperature is applied to ensure that the areas of the heat exchangers stay within reasonable limits in the solution network. Since minimum approach temperature affects both the structure of the HEN and the total annualized cost, its value needs to be determined during the optimization procedure. The current work proposes a procedure for HEN synthesis which determines the best, n-best, or all feasible HENs for all periods considering variable approach temperature. The proposed method extends the P-graph-based HEN synthesis method for determining all feasible networks in all periods. Three case studies are used to demonstrate the application of the proposed method. The case studies show that while the commonly applied minimum approach temperature of 10 °C does indeed gives near-optimal results, some problems need different values, such as 25 °C or 30 °C.

Open Access: Yes

DOI: 10.1016/j.tsep.2023.101912

Case Study: Optimizing Grading Ring Design for High Voltage Polymeric Insulators in Power Transmission Systems for Enhanced Electric Field and Voltage Distribution by Using a Finite Element Method

Fatiha Aouabed Adrienn Dineva Esraa Aziz Hossam Abdellah

Publication Name: Energies

Publication Date: 2023-07-01

Volume: 16

Issue: 13

Page Range: Unknown

Description:

This research paper aims to investigate the optimal design of grading rings for high-voltage polymeric insulators in an actual power transmission system, with a focus on improving the electrical representation of the insulator strings. One such subsidiary accessory commonly used with porcelain and polymer insulator strings is the grading ring, which is employed to improve the electric field and voltage distribution surrounding the insulator string. The efficiency of insulator strings can be enhanced by grading rings, as they facilitate a more linear potential division along the strings. The design parameters of grading rings significantly influence their performance on insulator strings. In this study, we examine the optimal design of the grading rings of high-voltage polymer insulators, since no uniform design methodology has been developed for high-voltage polymer insulators, and their optimization is currently the subject of many research studies. The electric field on an outdoor polymeric insulator is examined using finite element method (FEM) software and COMSOL Multi-Physics program. A 2D model is utilized to simulate a 220 kV polymeric insulator. The effectiveness of high-voltage polymeric insulators greatly depends on the dimensions and locations of the grading rings. Therefore, the impacts of the radius of the grading ring and that of its tube and the tube’s vertical position are thoroughly investigated, under dry and humid conditions. To achieve this objective, a search algorithm is employed to adjust the dimensions and locations of the grading ring. The optimization approach in this study is based on determining the maximum electric field across the insulator surface, while ensuring that it remains below the corona initiation level.

Open Access: Yes

DOI: 10.3390/en16135235

Simplified Routing Mechanism for Capsule Networks

Claudiu Radu Pozna Áron Ballagi János Hollósi

Publication Name: Algorithms

Publication Date: 2023-07-01

Volume: 16

Issue: 7

Page Range: Unknown

Description:

Classifying digital images using neural networks is one of the most fundamental tasks within the field of artificial intelligence. For a long time, convolutional neural networks have proven to be the most efficient solution for processing visual data, such as classification, detection, or segmentation. The efficient operation of convolutional neural networks requires the use of data augmentation and a high number of feature maps to embed object transformations. Especially for large datasets, this approach is not very efficient. In 2017, Geoffrey Hinton and his research team introduced the theory of capsule networks. Capsule networks offer a solution to the problems of convolutional neural networks. In this approach, sufficient efficiency can be achieved without large-scale data augmentation. However, the training time for Hinton’s capsule network is much longer than for convolutional neural networks. We have examined the capsule networks and propose a modification in the routing mechanism to speed up the algorithm. This could reduce the training time of capsule networks by almost half in some cases. Moreover, our solution achieves performance improvements in the field of image classification.

Open Access: Yes

DOI: 10.3390/a16070336

Stability focused evaluation and tuning of special ground vehicle tracking algorithms

Antal Hiba Ádám Kisari Mihály Nagy Istvan Drotar Erno Simonyi Péter Bauer Gergely Istvan Kuna

Publication Name: IFAC Papersonline

Publication Date: 2023-07-01

Volume: 56

Issue: 2

Page Range: 9282-9287

Description:

This paper deals with a special tracking problem when a ground vehicle should be tracked by a multicopter flying ahead of the vehicle. Pre-designed vehicle route is assumed and the UAV stops or slows down at every intersection to react to route changes. After introducing the problem, the methods applied in a real flight demonstration in the Smart City module of ZalaZONE proving ground are presented. Then new methods are introduced to possibly improve performance. The main focus of the article is the evaluation of the stability of the methods and the provision of tuning guidelines. All of the introduced methods is tuned based-on the guidelines considering real ground vehicle test data and the high fidelity simulation of the applied multicopter. The two best methods are compared in detail and guidelines of their applicability are provided.

Open Access: Yes

DOI: 10.1016/j.ifacol.2023.10.212

Mechanical and morphological properties of PP/XNBR blends produced with rubber latex

László Lendvai

Publication Name: Journal of Polymer Research

Publication Date: 2023-07-01

Volume: 30

Issue: 7

Page Range: Unknown

Description:

In this work, polypropylene (PP)/carboxylated acrylonitrile butadiene rubber (XNBR) binary blends were prepared with the elastomer component dosed in its suspension (latex) form into the polymer matrix during melt compounding. For this purpose, samples containing 0-20 wt.% rubber were prepared using two different PP grades as matrices with lower and higher viscosity. Analogous reference samples with the same composition were also fabricated using traditional melt mixing by introducing the rubber in its dry, bulk form in order to analyze the efficiency of the latex route. Mechanical, thermomechanical and morphological analyses were used to investigate the structure-property relationships of the blends. Based on the SEM images the average domain size of the dispersed XNBR domains became markedly smaller when the rubber was introduced in its suspension form into the PP. Based on the Charpy impact tests and the tensile test results, the decreased rubber domain size led to improved ductility and toughness. The improvement was more prominent when the difference between the viscosity of the PP matrix and the XNBR rubber was higher.

Open Access: Yes

DOI: 10.1007/s10965-023-03660-3

The Impact of Social Media Relationships on e-WOM in Syria and Hungary

Anikó Tompos Jawad Abo Khair

Publication Name: Review of Applied Socio Economic Research

Publication Date: 2023-06-29

Volume: 25

Issue: 1

Page Range: 52-65

Description:

Cultural values play a crucial role in the formation of individuals’ behaviour. With the emergence of social networking sites, which have formed a parallel world to the real world, the behaviour of individuals and their motives to engage in electronic word of mouth (eWOM) on social media platforms has become extremely important for brands. Due to a relative lack in studies focusing on the cultural differencebased impact of social relationships on eWOM in social media, the present study seeks to address this gap as its broad objective is to investigate the effect of social relationship variables on eWOM in social media by comparing two different cultures, namely Syria and Hungary in order to explore whether social relationships exert a more significant impact on eWOM in a collectivistic society than in an individualistic one. An explanatory research design was adopted and the data was collected by means of a questionnaire survey. The final sample included 113 Syrian and 90 Hungarian respondents, all of them aged 35 or below. It was found that tie strength among young adults has a more positive impact on eWOM in Syria than in Hungary, while no homophily impact was found on eWOM in either. Regarding the other social relationship variables examined in the study (trust, normative and informational influences), the results showed that they do not have a more positive impact on eWOM in Syria than in Hungary. The research is believed to have contributed to previous investigations on the impact of social relationships on eWOM via social media by providing insights into the role of a cultural value dimension in determining the extent to which individuals are affected by their cultural background, whether collectivistic or individualistic, when they interact in social media platforms. At the same time, it is acknowledged that the study has limitations thus future examinations are necessary.

Open Access: Yes

DOI: 10.54609/reaser.v25i1.335

The Concept of Financial Stability in Theory and Law

János Kálmán

Publication Name: Financial and Economic Review

Publication Date: 2023-06-28

Volume: 22

Issue: 2

Page Range: 54-76

Description:

State intervention in the functioning of the economy is necessarily based on some public interests, which may serve as a reason for restrictive state action against the individual, or their freedoms and rights. In legislation, financial stability can be identified as a form of public interest, whereby the need to define the substance of the concept is expressed as an expectation towards the legislator, all the more so because it forms the basis of significant administrative intervention of the public authority type. The study analyses how the concept of financial stability appears in the literature, in legislation and in legal enforcement. Although the concept of financial stability is strongly reflected in the theoretical literature and even in legislation and legal enforcement, its substance is difficult to capture and has evolved constantly. In view of the above, the author offers a definition for the general legal concept of financial stability.

Open Access: Yes

DOI: 10.33893/FER.22.2.54