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Found 6319 publications

Surrogate Model-based Optimization of Electrical Machines in Ārtap Framework

Miklós Kuczmann Tamas Orosz Attila Nyitrai

Publication Name: Proceedings 2021 IEEE 19th International Power Electronics and Motion Control Conference Pemc 2021

Publication Date: 2021-04-25

Volume: Unknown

Issue: Unknown

Page Range: 514-518

Description:

For accurate modeling of electrical machines the solution multiple physical fields simultaneously in 3D is necessary. Therefore, the optimization of these machines is an computationally expensive optimization problem. The novel artificial intelligence methods and surrogate modeling techniques based on hp-adaptive FEM techniques can significantly reduce the computational cost. In case of a cogging torque or a torque ripple calculation, many simulations should be performed to make an accurate estimation of a single quantity. The number of calculations can be reduced by using surrogate modeling techniques. However, the surrogate model-based model's extrema can differ from the original task's optima. This paper presents a surrogate-model based cogging torque minimization of an axial flux permanent magnet synchronous machine. The objective function of this optimization is the cogging torque, the full solution space is explored to examine and show the robustness of the different kind of solutions.

Open Access: Yes

DOI: 10.1109/PEMC48073.2021.9432546

Feedback linearization with integrator of DCDC buck converter taking into account parasitic elements

Miklós Kuczmann Miklos CSIZMADIA

Publication Name: Proceedings 2021 IEEE 19th International Power Electronics and Motion Control Conference Pemc 2021

Publication Date: 2021-04-25

Volume: Unknown

Issue: Unknown

Page Range: 97-101

Description:

This paper presents the feedback linearization based control of DC/DC buck converter, the output voltage controlled. Also, the presence of parasitic elements are not studied in detail in a previous article, therefore the applied state space model are taking into account of those. The high slew rate of the controller cause inrush current during start-up, which have been examined and reduced. The linearized system has been investigated with linear quadratic regulator (LQR) through an example and simulated via Matlab.

Open Access: Yes

DOI: 10.1109/PEMC48073.2021.9432632

Models for predicting the suction of heaving compacted soils using geotechnical properties

Elizabeth Theron Armand Augustin Fondjo R. P. Ray

Publication Name: Iop Conference Series Earth and Environmental Science

Publication Date: 2021-04-20

Volume: 727

Issue: 1

Page Range: Unknown

Description:

Soil suction is the major property that controls the behaviour of unsaturated soils. Suction estimation is challenging both in the lab and the field. Various instruments to measure the suction have been developed with the recent technological advancements. Nonetheless, there are still limitations in regards to the reliability, cost, suction range, accessibility, scope of activity, and appropriateness for use either within the field or lab settings. The filter paper method is probably the simplest procedure to measure the suction for the entire range both in the field and the lab. Nevertheless, the procedure takes time. To alleviate the requirement for conducting this test, it becomes imperative to develop mathematical predictive models for soil suction. In this study, a detailed survey was carried out across the Free State province, South Africa, and sampling points identified. Samples were tested for their geotechnical properties. The influence of the geotechnical properties on soil suction was studied. Multivariate regression analysis was carried out utilizing MINITAB 18 program to develop the mathematical predictive models.

Open Access: Yes

DOI: 10.1088/1755-1315/727/1/012016

A new efficient tour construction heuristic for the Traveling Salesman Problem

Boldizsar Tuu-Szabo Ali Jawad Ibada Ĺaszĺo T. Ḱoczy

Publication Name: ACM International Conference Proceeding Series

Publication Date: 2021-04-10

Volume: Unknown

Issue: Unknown

Page Range: 71-76

Description:

The creation of the initial population is an essential part of the population based evolutionary algorithms. An appropriate initial population could lead to much faster convergence speed; in contrast, an inappropriate initial population could even cause getting stuck in a local optimum. In this paper, we will propose a new efficient heuristic method to create initial individuals for the Traveling Salesman Problem (TSP), which we will call Circle Group Heuristic (CGH). The results show that CGH creates better tours compared with other well-known heuristic tour construction methods.

Open Access: Yes

DOI: 10.1145/3461598.3461610

Chinese foreign direct investments in hungary from the perspective of BRI, international capacity cooperation, and made in China 2025

Eszter Lukács Katalin Völgyi

Publication Name: Contemporary Chinese Political Economy and Strategic Relations

Publication Date: 2021-04-01

Volume: 7

Issue: 1

Page Range: 413-446

Description:

This study analyses Chinese investments in Hungary from the perspective of three initiatives (Belt and Road Initiative, International Cooperation in Industrial Capacity and Equipment, and Made in China 2025) which are in line with China's "Go global" strategy and among other things aimed at promoting the spread of Chinese companies and products abroad. The findings show a vivid cooperation between China and Hungary in automotive, ICT, renewable energy, chemical, transportation/logistics and banking sector through the three abovementioned initiatives.

Open Access: Yes

DOI: DOI not available

Experimental comparison of field and accelerated random vertical vibration levels of stacked packages for small parcel delivery shipments

Péter Böröcz Bence Molnar

Publication Name: Applied Sciences Switzerland

Publication Date: 2021-04-01

Volume: 11

Issue: 7

Page Range: Unknown

Description:

In the last decade, there has been a significant increase in parcel delivery shipments all over the world due to online stores and consumer demand to receive the products in a shorter period of time. It is especially true when situations like COVID-19 limits personal purchases in shopping malls as well as grocery and pharmaceutical stores. This often means that courier operators try to deliver packages utilizing vehicles with racks or shelves, which during the COVID-19 epidemic are not there anymore. This study measured the vertical vibration levels that occur in stacked parcels during express delivery versus the simulation technique in the laboratory. The goal of this paper was to measure and compare the vibration levels between laboratory practice and field transportation. For the measurement a three-layer stacked unit was built to observe the vibration levels on different road conditions in a parcel delivery vehicle and ASTM vibration profile (ASTM International). Then the measured acceleration-time data were analyzed in terms of power spectral densities (PSD) and the presented statistical data provided an understanding of the variability of intensity in different levels in stacked unit. The results showed that the vibration level increases in the stacked load upwards and with worse road conditions, but even in the worst case it did not reach those vibration levels that the laboratory test showed. Moreover, the layers of the stacked unit are in out-of-phase motion in the field, while the stacked unit in the vibration simulation usually is in-phase motion. Results indicate that the proposed vibration simulation does not correlate well with typical field vibration. This is fundamentally true as during a forced vibration created by a single-axis shaker, do not account for additional inputs occurring simultaneously creating an off-balance to the loads and as a result are less severe than simulated conditions. These findings are limited to single axis vibration simulation and unsecured loads.

Open Access: Yes

DOI: 10.3390/app11072927

Review on the occurrence of the mcr-1 gene causing colistin resistance in cow's milk and dairy products

E. Lakatos Ágnes Nagy V. Kapcsándi Székelyhidi Rita

Publication Name: Heliyon

Publication Date: 2021-04-01

Volume: 7

Issue: 4

Page Range: Unknown

Description:

Both livestock farmers and the clinic use significant amount of antibiotics worldwide, in many cases the same kind. Antibiotic resistance is not a new phenomenon, however, it is a matter of concern that resistance genes (mcr - Mobilized Colistin Resistance - genes) that render last-resort drugs (Colistin) ineffective, have already evolved. Nowadays, there is a significant consumption of milk and dairy products, which, if not treated properly, can contain bacteria (mainly Gram-negative bacteria). We collected articles and reviews in which Gram-negative bacteria carrying the mcr-1 gene have been detected in milk, dairy products, or cattle. Reports have shown that although the incidence is still low, unfortunately the gene has been detected in some dairy products on almost every continent. In the interest of our health, the use of colistin in livestock farming must be banned as soon as possible, and new treatments should be applied so that we can continue to have a chance in fighting multidrug-resistant bacteria in human medicine.

Open Access: Yes

DOI: 10.1016/j.heliyon.2021.e06800

Measurement and analysis of industrial forklifts vibration levels for unit load testing purposes

Laszlo Horvath Péter Böröcz Yu Yang Huang

Publication Name: Applied Sciences Switzerland

Publication Date: 2021-04-01

Volume: 11

Issue: 7

Page Range: Unknown

Description:

Forklifts are one of the most common types of material handling equipment used in warehouses and distribution centers. Vibration generated by forklifts may have an effect on the performance of unit loads and product damage rates. Historical research projects have focused predominantly on the measurement of vibration for over-the-road transportation. Thus, there is still a lack of understanding of the level of vibration caused by forklifts. The goal of this study was to understand how the vibration that is experienced by unit loads while being transported by forklifts is affected by factors such as speed, road condition, unit load weight, type of forklift, and sensor location. For this study, power spectral density (PSD) measurements were collected using a Lansmont Saver 9X30 data logger. Vibration levels were measured for three different industrial forklifts on two different surface types. The forklifts were driven at two different speeds while carrying two different unit load weights. For all of these conditions, the vibration levels were measured at the forklift carriage, at the back of the fork tine heel, and at the fork tine tips. The results obtained show that the highest vibrational intensity occurred at 3–4 Hz, while the highest overall Grms value observed was 0.145 G2/Hz (between 1–200 Hz). An increase in the forklift speed caused an increase in vibration intensity. In contrast, an increase in the unit load weight carried by the forklift caused a decrease in vibration intensity. Among the three forklifts studied, the gas-powered forklift had the highest vibration intensity, and all forklifts, when driven on asphalt, experienced more vibration.

Open Access: Yes

DOI: 10.3390/app11072901

Linseed oil supplementation affects fatty acid desaturase 2, peroxisome proliferator activated receptor gamma, and insulin-like growth factor 1 gene expression in turkeys (Meleagris gallopavo)

Eszter Zsédely E. Lakatos Károly Tempfli Klaudia Szalai András Gáspárdy Ágnes Bali Papp

Publication Name: Animal Bioscience

Publication Date: 2021-04-01

Volume: 34

Issue: 4

Page Range: 662-669

Description:

Objective: Effects of linseed oil (LO) supplementation on the fat content and fatty acid profile of breast meat, and the expression of three genes in the liver, breast muscle and fat tissues of commercial 154-day-old hybrid male turkeys were investigated. Methods: The animals in the control group were fed a commercially available feed and received no LO supplementation (n = 70), whereas animals in the LO group (n = 70) were fed the same basic diet supplemented with LO (day 15 to 21, 0.5%; day 22 to 112, 1%). The effect of dietary LO supplementation on fatty acid composition of breast muscle was examined by gas chromatography, and the expression of fatty acid desaturase 2 (FADS2), peroxisome proliferator activated receptor gamma (PPARγ), and insulin-like growth factor 1 (IGF1) genes was analysed by means of quantitative reverse transcription polymerase chain reaction. Results: The LO supplementation affected the fatty acid composition of breast muscle. Hepatic FADS2 levels were considerably lower (p<0.001), while adipose tissue expression was higher (p<0.05) in the control compared to the LO group. The PPARγ expression was lower (p<0.05), whereas IGF1 was higher (p<0.05) in the fat of control animals. There were no significant (p>0.05) differences in FADS2, PPARγ, and IGF1 gene expressions of breast muscle; however, omega-6/omega-3 ratio of breast muscle substantially decreased (p<0.001) in the LO group compared to control. Conclusion: Fatty acid composition of breast meat was positively influenced by LO supplementation without deterioration of fattening parameters. Remarkably, increased FADS2 expression in the liver of LO supplemented animals was associated with a significantly decreased omega-6/omega-3 ratio, providing a potentially healthier meat product for human consumption. Increased PPARγ expression in fat tissue of the LO group was not associated with fat content of muscle, whereas a decreased IGF1 expression in fat tissue was associated with a trend of decreasing fat content in muscle of the experimental LO group.

Open Access: Yes

DOI: 10.5713/ajas.20.0030