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Number of results: 8
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Abstract

Casing treatment in the form of circumferential grooves over a rotor blade tips is used for improvement of an axial compressor performance. Usually, these grooves extend compressor’s stall range (stable operational range) but decrease its efficiency. In the paper, there are presented main results of investigations on grooves that influence positively efficiency of compressor. There were investigated traditional (typical) and newly developed groove configurations. Certain grooves combine increase in efficiency with extension in stall range.

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Authors and Affiliations

Vitaliy Nezym
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Abstract

The proper functioning of the perinatal sucking reflex in calves is essential for the prevention of milk leakage into the rumen. The complex process behind its regulation is mediated at the gut level via multiple excitatory and inhibitory neurotransmitters, of which acetylcholine and nitric oxide are of fundamental importance. The aim of our study was to depict age-related alterations in the cholinergic and nitrergic innervation of the esophageal groove (EG) using immunohistochemistry and Real-Time PCR methods. We found out that the highest number of cholinergic nerve cells was present in the second trimester fetuses. From this developmental stage onward, their amount was gradually decreasing and reached the lowest value in 4-year-old cows. The same developmental pattern was observed for nitrergic nerve structures with the highest percentage of nitrergic neurons in the third trimester fetuses. Our observations prove that both neuronal populations are crucial for a proper closure of EG in calves. Therefore, their contribution to a general neuronal activity in the ENS diminishes with age as the high motility of a gastric groove is not necessarily required in older cattle.
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Bibliography

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Authors and Affiliations

M. Marszałek
1
T. Serzysko
1
W. Sienkiewicz
1

  1. Department of Animal Anatomy, Faculty of Veterinary Medicine, University of Warmia and Mazury, Oczapowskiego 13, 10-719 Olsztyn, Poland
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Abstract

In this paper, a conventional mushroom-type EBG unit cell is made compact by etching a C-slot at its conducting surface. Further, the C-slotted mushroom-type EBG unit cell is coupled with a microstrip line using a novel groove-coupling technique to design a notch filter. The arrangement has achieved in the reduction of the electrical size of the mushroom type EBG unit cell by 46:15% and create a stop band suppression of -12 dB. The proposed EBG is applied to notch a narrow band centered at 5:2 GHz along with an ultra-wideband antenna. The far field gain of the antenna is suppressed by -5:8 dBi along the direction of its major lobe at 5:2 GHz. The overall size of the antenna system is 19x27x1:6mm3 which is compact. The performance of the antenna is validated from the simulation and measured results.

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Authors and Affiliations

Kumaresh Sarmah
Sivaranjan Goswami
Angana Sarma
Sunandan Baruah
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Abstract

The surface temperature of steel billets during hot rolling can reach up to 1200 °C. High temperature promotes rapid oxidation of the surface of steel billets, forming a dense oxide layer similar to fish scales. If not removed in a timely manner, it will damage the surface of the steel billets and exacerbate the wear of the rolls during the descaling process. There are many methods for descaling, but high-pressure water jet has become the main method for descaling due to its excellent descaling performance, low cost, and ease of use. The tip of the descaling nozzle serves as the main component, and its structural parameters affect the final descaling effect. This research changes the shape factor of the nozzle groove curve and the diameter of the nozzle throat, and performs computational fluid dynamics (CFD) simulations on the simplified nozzle external flow field. The axial velocity at the center of the jet generates a velocity peak at 0.5-1 Dc. The peak velocity increases with the increase of shape factor and throat diameter, and the influence of shape factor on the peak velocity is greater. For a constant target distance, the length of the velocity stable section along the jet impact line increases with the increase of the shape factor. The maximum value of dynamic pressure increases, and the smaller the target distance, the greater the dynamic pressure difference. The trend of water volume is roughly the same as that of dynamic pressure.
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Bibliography

[1] Ma, F., Li, Y. & Song, Z. M. (2011). Jet performance testing of high-pressure waterjet descaling nozzles. Advanced Materials Research. 314, 2408-2413. https://doi.org/10.4028/www.scientific.net/AMR.314-316.2408.
[2] Baofu Kou, Pengliang Huo, Xiaohua Hou, (2020). Research on the influence of external parameters of fan-type nozzle on water jet performance. Shock and Vibration. 2020, 4386259, 1-16. https://doi.org/10.1155/2020/4386259.
[3] Jiang, T., Huang, Z., Li, J., Zhou, Y. & Xiong, C. (2022). Effect of nozzle geometry on the flow dynamics and resistance inside and outside the cone-straight nozzle. ACS omega. 7(11), 9652-9665. https://doi.org/10.1021/acsomega.1c07050.
[4] Sushma, L., Deepik, A. U., Sunnam, S. K. & Madhavi, M. (2017). CFD investigation for different nozzle jets. Materials Today: Proceedings. 4(8), 9087-9094. https://doi.org/10.1016/j.matpr.2017.07.263.
[5] Gu, B., Hu, R., Wang, L., & Xu, G. (2022). Study on the influence rule of high-pressure water jet nozzle parameters on the effect of hydraulic slotting. Geofluids. 2022, 4510194. https://doi.org/10.1155/2022/4510194.
[6] Frick, J.W. (2009). Optimisation of technologies for hydro-mechanical descaling of steel. Metallurgical Research & Technology. 106(2), 60-68. https://doi.org/10.1051/ metal/2009015.
[7] Zhang, D., Wang, H., Liu, J., Wang, C., Ge, J., Zhu, Y., Chen, X. & Hu, B. (2022). Flow characteristics of oblique submerged impinging jet at various impinging heights. Journal of Marine Science and Engineering. 10(3), 399. https://doi.org/10.3390/jmse10030399.
[8] Song, X., Lyu, Z., Li, G. & Hu, X. (2017). Numerical analysis of the impact flow field of multi-orifice nozzle hydrothermal jet combined with cooling water. International Journal of Heat and Mass Transfer. 114, 578-589. https://doi.org/10.1016/j.ijheatmasstransfer.2017.06.106.
[9] Gongye, F., Zhou, J., Peng, J., Zhang, H., Peng, S., Li, S. & Deng, H. (2023). Study on the removal of oxide scale formed on 300 M steel special-shaped hot forging surfaces during heating at elevated temperature by a high-pressure water descaling process. Materials. 16, 1745, 1-14. https://doi.org/10.3390/ma16041745.
[10] Wen, J., Qi, Z., Behbahani, S. S., Pei, X. & Iseley, T. (2019). Research on the structures and hydraulic performances of the typical direct jet nozzles for water jet technology. Journal of the Brazilian Society of Mechanical Sciences and Engineering. 41, 1-12. https://doi.org/10.1007/s40430-019-2075-2.
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[12] Huang, F., Mi, J., Li, D. & Wang, R. (2020). Impinging performance of high-pressure water jets emitting from different nozzle orifice shapes. Geofluids. 2020, 8831544. https://doi.org/10.1155/2020/8831544.
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Authors and Affiliations

Bowen Yang
1
Guangqiang Liu
2
Chengcheng Xu
3
Kun Liu
1
ORCID: ORCID
Peng Han
1

  1. School of Materials and Metallurgy, University of Science and Technology Liaoning, China
  2. School of Civil Engineering, University of Science and Technology Liaoning, China
  3. Cold Rolling Mill Plant, ANGANG Steel Company Limited, China
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Abstract

The article presents the results of the last stage of work on the impact of changes in the roll pass design on the state of residual stresses in railway rails. The discussed stage includes the summary of industrial experiments of rolling 60E1 rails with a length of 120 meters using a modified pass design of roll grooves. The rolling technology has been deeply modified, ranging from the finishing stand, through the pre-finishing stand, to the semi-finishing stand. The rails in this experiment were cooled using standard cooling technology and then straightened using innovative vertical straightener shaped rollers. Residual stresses were tested using the strain gauge method and the hole-drilling strain gauge method by drilling a hole in the rail axis and at a distance of 14 millimetres from its axis. The resulting tensile stresses in the rail foot were reduced to an average level of less than 43% in relation to the requirements of the EN13674-1 standard.
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Authors and Affiliations

S. Żak
1
ORCID: ORCID
D. Woźniak
2
ORCID: ORCID

  1. ArcelorMittal Poland S.A., 92 Józefa Piłsudskiego 9 Av. 41-308 Dąbrowa Górnicza, Poland
  2. Łukasiewicz Research Network – Institute for Ferrous Metallurgy, 12 Karola Miarki Str., 44-100 Gliwice, Poland
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Abstract

7N01-T4 aluminum alloy was welded by metal inert gas welding and the influence of V-groove angle on joint fatigue properties was investigated. The results indicate that the volume of fusion zone (FZ) and the grains in FZ become small when the groove angle decreases to 50° from 70°. Most pores distribute at the FZ edge and fewer pores are formed in the small angle joint. The fatigue crack mainly initiates at the transition region between the weld passes due to the pore concentration. The small angle contributes to increasing joint fatigue properties, especially at the low stress level. The fatigue strength of 50° joint is 103.06 MPa which is 15.3% higher than that of 70°joint.

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Authors and Affiliations

Zhongwei Ma
Qinghua Li
Lin Ma
ORCID: ORCID
Zhaokun He
Zhimin Liang
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Abstract

The flow-induced noise mechanism of a 5000 rpm high-speed gear pump is explored. On the basis of the CFD technology and the Lighthill acoustic analogy theory, a numerical model of the flow-induced noise of a high-speed gear pump is constructed, and the effect of oil suction pressure (0.1–0.2 MPa) on the internal flow field and flow-induced noise characteristics of the high-speed gear pump is investigated. To evaluate the accuracy of the numerical simulation, a noise testing platform for high-speed gear pumps was developed. Adding an oil replenishment groove to the high-speed gear pump suppresses its flow-induced noise. The results indicate that the discrete noise at the fundamental frequency and its harmonic frequency is the primary component of the flow-induced noise of the pump and that the oil-trapped area is the principal source of vibration. The overall sound pressure level of flow-induced noise in the inlet and outlet areas decreases with distance from the oil-trapped area, and the sound pressure level in the outlet area is greater than that in the inlet area. The oil replenishment groove may considerably minimize cavitation noise, enhance the oil absorption capacity, and reduce the outer field’s overall sound pressure level by 4–5 dB.
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Authors and Affiliations

Peng Zhan
1
Yan Qiang
1
Zhiyuan Jiang
1
Runxue Yang
1
Liejiang Wie
1

  1. Energy and Power Engineering College, Lanzhou University of Technology Qilihe District, Lanzhou, Gansu Province, P.R. China
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Abstract

Wood plastic composite (WPC) is a lightweight material, resistant against corrosion and damage, with recyclability of consuming materials. These materials usually used in marine structures frequently due to their unique features. In order to strengthen beams made by this material, usually Fibre-reinforced plastic (FRP) sheets are used, and one of the fracture modes in these beams is debonding of FRP sheet from the surface of the beams. To deal with this problem some grooves are used in the surface of the beam to improve the contact surface. The grooves include longitudinal, transverse and diagonal grooves. The main goal of this study is to assess different grooving methods in WPC-FRP beams. In this regard, primarily criteria (improving resistance, performance speed, performance complexity, performance costs, displacement and absorbing energy) were determined through interviews with experts in this field in order to assess the beams. Then, SWARA method employed to evaluate criteria with a policy based perspective and finally EDAS method applied for evaluating related alternatives. Based on obtained results, the longitudinal groove method is the best way of strengthening WPC beams to prevent debonding.

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Authors and Affiliations

Mahdi Chini
Shahid Arefi Lale
Sarfaraz Zolfani Hashemkhani
Leonas Ustinovicius

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