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Schematic diagram of the ultrasonic testing (UT) set-up, depicting the test screen and compression probe.
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The sugar mill roller shaft is one of the critical parts of the sugar industry. It requires careful manufacturing and testing in order to meet the stringent specification when it is used for applications under continuous fatigue and wear environments. For heavy industry, the manufacturing of such heavy parts (>600 mm diameter) is a challenge, owing...
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... relationship between velocity, frequency and wavelength is given by v = fλ. The UT inspection system incorporates a portable probe of transmitter/receiver, transducer, and a display screen (see details in Figure 5). A pulse is generated by imposing an alternating voltage that activates a piezoelectric probe crystal to produce signals by coupling the probe to it. ...
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Over the past few months, the world has witnessed how COVID-19 pandemic disrupted the supply chain of the textile, apparel and fashion manufacturing (TAFM) industry in various unprecedented ways. As the global textile market is interconnected, this outbreak has a global impact due to travel restrictions and raw materials shortages. This study highl...
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... All these actions lead to protecting the natural environment. The variety of technological environments found in food processing machinery and equipment means that components of moving nodes are subject to extremely rapid wear under the simultaneous effects of friction, thermal, and corrosive forcing [4][5][6][7][8][9]. Due to the variability in operating conditions, the wear of equipment components varies. ...
Providing high-quality machinery and equipment in technical terms is an activity aimed primarily at ensuring the high reliability of nodes. Reliability of machinery and equipment is mainly characterized by resistance to destructive processes. Mutual displacement of parts causes destructive friction phenomena, the intensity of which can be intensified by the interaction of specific technological environments. The article presents the results of research on ring-on-ring samples made of C45 steel in the non-heat-treated state, which were subjected to mechanical, corrosive, and abrasive wear and various combinations of them. The main purpose of the study was to determine the wear that results from the action of destructive friction and corrosive processes with the presence of abrasive material in the tribological node. The results supplement the knowledge of material wear under the simultaneous action of several destructive factors. Based on the study, it was noticed that the sum component of mechanical-abrasive-corrosive interactions is about 40-50% of the total wear. Mass loss resulting from simultaneous mechanical and abrasive interactions is equal about one-third of the total wear. In addition, it was observed that the effects of the interactions of friction (mechanical), corrosive and abrasive excitations are synergistic in nature, which lead to increases in the total wear of the tested samples made of steel. The results of the research are of practical importance and allow for wear-optimal selection of material in the friction node of modern machinery and equipment.
... Furthermore, the causes of birth defects have also been widely discussed, but have not yet been fully elucidated [11]. By identifying the source of the defect, the defect rate can also be reduced or eliminated [12]. ...
NKX2.5 is a transcription factor that plays a key role in cardiovascular growth and development. Several independent studies have been previously conducted to investigate the association between the single-nucleotide polymorphism (SNP) 606G >C (rs3729753) in the coding region of NKX2.5 and congenital heart disease (CHD). However, the results of these studies have been inconsistent. Therefore, the present study aimed to reveal the relationship between NKX2.5 SNP 606G >C and the risk of CHD as possible in the Chinese population through meta-analysis. After retrieving related articles in PubMed, MEDLINE, EMBASE, Web of science, Cochrane, China National Knowledge Infrastructure, Wanfang DATA, and VIP database until August 2021, a total of eight studies were included in the present meta-analysis. The qualified research data were then merged into allele, dominant, recessive, heterozygous, homozygous, and additive models. Overall results of the current meta-analysis showed that 606G >C was not associated with CHD of the Chinese population in any model. In addition, subgroup analysis based on CHD type gave the same negative result. Results of sensitivity analysis showed that there was no significant correlation after the deletion of each study. Furthermore, it was noted that the results were negative and the heterogeneity was not significant. In conclusion, it was evident that NKX2-5 SNP 606G >C may not lead to the risk of CHD in Chinese population.
... The idea of ultrasonic testing of material, adapted from[47]. ...
Fibre-reinforced polymer materials (FRP) are increasingly used to reinforce structural elements. Due to this, it is possible to increase the load-bearing capacity of polymer, wooden, concrete, and metal structures. In this article, the authors collected all the crucial aspects that influence the behaviour of concrete elements reinforced with FRP. The main types of FRP, their characterization, and their impact on the load-carrying capacity of a composite structure are discussed. The most significant aspects, such as type, number of FRP layers including fibre orientation, type of matrix, reinforcement of concrete columns, preparation of a concrete surface, fire-resistance aspects, recommended conditions for the lamination process, FRP laying methods, and design aspects were considered. Attention and special emphasis were focused on the description of the current research results related to various types of concrete reinforced with FRP composites. To understand which aspects should be taken into account when designing concrete reinforcement with composite materials, the main guidelines are presented in tabular form.
... Inclusions are undesirable metallic or nonmetallic chemical compounds of oxygen, sulphur, nitrogen, and other unavoidable nonmetallic impurities created during the manufacturing process and embedded in the cast components. They formed a separate phase [8,11,20]. Nonmetallic inclusions have different chemical origins and give the cast material other mechanical properties, such as corrosion resistance, machinability, toughness, and formability. Depending on their source, they can be classified into endogenous or exogenous inclusions. ...
... other hand, are the products that originated from the erosion of refractory materials, ladle lining, mould sand, slag particles, and inclusions derived from ferroalloys, flux materials as well as other starting materials that do not float to the surface of the liquid metal or dissolve in it [11,20]. A more common source of inclusions in cast iron comes from undissolved ferrosilicon alloy [20,21]. ...
... other hand, are the products that originated from the erosion of refractory materials, ladle lining, mould sand, slag particles, and inclusions derived from ferroalloys, flux materials as well as other starting materials that do not float to the surface of the liquid metal or dissolve in it [11,20]. A more common source of inclusions in cast iron comes from undissolved ferrosilicon alloy [20,21]. This ferroalloy is a common source of silicon and is added to cast iron melting to decrease the melting point of the metal and improve its fluidity. ...
A metallurgical failure analysis was conducted on a grey cast-iron (GCI) automotive brake disc to unravel the root cause of its premature failure. The brake rotor had been in service for about one year and three months and covered a total mileage of 17 173 km before the failure was reported. However, this investigation aims at identifying the causes of the failure and proffer solutions to forestall similar future occurrences. Chemical composition analysis on the disc suggested that its elemental composition is within the required standard for such a component. The disc swan-neck thickness, hardness and microstructure analysis conformed adequately with the material specifications. SEM-EDS study of the fracture surface showed the presence of admixture oxides of Al, Mg, Si, Na, Ca, Ti and Mn, suggesting nonmetallic (slag and sand) inclusions. A fractographic study of the broken surface indicated that the failure was caused by these oxide inclusions embedded in the swan neck region of the rotor during the casting process. Microcracks were observed to have been initiated within the inclusion particles and propagated through the graphite-pearlite interface, eventually leading to the disc failure. Recommendations are also provided to guide the operation of metal-casters to prevent the recurrence of nonmetallic inclusions, which can significantly diminish the service life of cast products.
... However, some obstacles remain: first, it needs to be checked whether the S-N curve of various weld details is suitable for new steel; secondly, making S-N curve requires previous load information to predict the fatigue life of the structure details, but the historic information is difficult to acquire, let alone determine the fatigue life; third, this method cannot assess the remaining life with the flange's test data, such as the distribution and size of the crack. In recent years, the method that combines fracture mechanics with finite elements has developed rapidly and become one of the main tools in the research of fatigue crack [2][3][4][5][6][7]. Atanasovska et al. carried out finite element analysis of corrosion fatigue crack and turbine shaft damage based on actual turbine shaft failure cases and proposed a new method to calculate the stress concentration coefficient [8]. ...
A fatigue test on the failure mode of flange shafts was conducted. The propagation characteristics of the initial crack at the junction between the shaft and the flange as well as its angle effect were studied. This study developed an analysis program of fatigue crack propagation, based on the APDL (ANSYS Parametric Design Language). It obtained the effective angle interval within which the initial crack is able to propagate. The fitting calculation formula was derived and the results showed that: (1) The initial crack at the junction between the shaft and the flange would propagate in the radial and axial directions; the unstable crack propagation would cause an abrupt fracture of the cross-section, failing connection; and the angle of initial crack was uncertain. (2) The crack followed the I-II-III mixed mode, which was dominated by mode I. An initial crack with a larger angle showed more noticeable II-III characteristics; KII and KIII affected the crack’s propagation angle in the radial and axial directions and they also affected the structure’s surface direction. (3) The deepest point A of the crack was located at the junction between the shaft and the flange. Its crack propagation can be divided into three stages: rapid growth (stage 1), steady decline (stage 2, buffer stage), and instability (stage 3). The initial crack angle not only affected the propagation rate at stage 1 but also influenced the fatigue life distribution of the structure during propagation. The larger the initial crack angle was, the smaller the proportion of buffer stage in the total fatigue life would be. Moreover, the propagation of crack with a larger initial angle reached instability faster after stage 1, which would cause an abrupt fracture of the cross-section. This was unfavorable for deciding the crack detection time or carrying out maintenance and reinforcement. (4) The crack propagation at the junction between the shaft and the flange was determined by the size relation between ΔKI and ΔKth, instead of the effective stress intensity factor. The effective stress intensity factor can partly reflect the law of crack propagation, but cannot serve as the only criterion for crack propagation; it must be combined with the effective angle interval, which was negatively correlated with the crack’s shape ratio, to determine whether the crack would propagate.
... Non-destructive testing (NDT) technology, e.g., ultrasonic testing (UT), magnetic particle inspection (MPI), radiographic testing (RT), etc., have been widely used in the industry [16]. MPI was utilized frequently among these methods owing to the demanding requirements of surface and near-surface quality in rollers More and more defects were considered as metallurgical defects, which were caused by inclusions created in deoxidation, reactions between molten steel, slag and refractory, or even slag entrapment [17][18][19][20][21][22][23][24]. Jamil et al. [24] found that alumina and oxide types non-metallic inclusions caused the failure of ultrasonic testing in the sugar mill shaft. ...
... MPI was utilized frequently among these methods owing to the demanding requirements of surface and near-surface quality in rollers More and more defects were considered as metallurgical defects, which were caused by inclusions created in deoxidation, reactions between molten steel, slag and refractory, or even slag entrapment [17][18][19][20][21][22][23][24]. Jamil et al. [24] found that alumina and oxide types non-metallic inclusions caused the failure of ultrasonic testing in the sugar mill shaft. Lu et al. [25] ...
... carbides, microstructure by heat treatment, etc. [27][28][29][30]. Meanwhile, few studies concerning the evolution and influence of inclusions in the large forged ingots were found [24]. Consequently, combined the appearance of ultrasonic defects on the post-forging rollers with the corresponding specimens during the plant steelmaking process, the origin, evolution, and improvement of defects have been analyzed and clarified. ...
Industrial tests and thermodynamic calculations were utilized to investigate the source and formation of magnetic particle inspection defects identified on the near-surface of the Cr5 back-up roll forged ingot, which was used in large cold rolling mills. The results showed that the linear aggregating SiO2-MnO-Al2O3 liquid inclusions up to 3 mm led to the flaw detection failure. SiO2-MnO-Al2O3 liquid inclusions were firstly formed in the inductive furnace. Due to its low contact angle, a huge amount of SiO2-MnO-Al2O3 liquid inclusions were inherited into the forged ingot. The formation of SiO2-MnO-Al2O3 liquid inclusions was attributed to the over-oxidation and relatively low aluminum content in the molten steel, as calculated by Factsage 8.1. Controlling the amount of aluminum in molten steel during the smelting process could modify the formation of SiO2-MnO-Al2O3 and CaO-SiO2-Al2O3 liquid oxide into solid Al2O3 type inclusions that were easily removed. Besides, the CaO-SiO2-Al2O3 liquid oxide could be transformed from CaO-Al2O3 type oxide by the significant loss of aluminum content during the VD process or slag entrapment. Certain content of aluminum in the molten steel could improve the flaw detection caused by the aggregating SiO2-MnO-Al2O3 inclusions effectively.
... Optical inspection may contribute to improving industrial production processes. For example, Jamil et al. [11] investigated the main causes for the rejection of sugar mill roller shafts after rough machining. Non-destructive (optical microscopy, SEM microscopy, X-ray spectroscopy, ultrasonic and magnetic particle testing) and destructive micro-and macrocrystallographic tests were carried out for this purpose. ...
The mechanical characterization of materials embraces many different aspects, such as, for example, (i) to assess materials’ constitutive behavior under static and dynamic conditions; (ii) to analyze material microstructure; (iii) to assess the level of damage developed in the material; (iv) to determine surface/interfacial properties; and (v) to optimize manufacturing processes in terms of process speed and reliability and obtain the highest quality of manufactured products [...]
... The new design shall guarantee a metal skin temperature below 750 K, to prevent copper infiltration into the steel plates [11]. Infiltration damages the base metal and may cause a catastrophic failure [12]. Figure 2 shows a micrograph of a S345J steel plate where the infiltration of copper can be appreciated. ...
Fire refining of blister copper is a singular process at very high temperatures (~1400 K),
which means the furnace is exposed to heavy thermal loads. The charge is directly heated by an
internal burner. The impurities in the charge oxidize with the flux of hot gases, creating a slag layer
on the top of the molten bath. This slag is periodically removed, which implies liquid metal flowing
through the furnace port. To address its malfunction, a re-design of the furnace port is presented in
this work. Due to the lack of previous technical information, the convective heat transfer coefficient
between the slag and the furnace port was characterized through a combination of an experimental
test and a three-dimensional transient model. Finally, the original design of the furnace port was
analyzed and modifications were proposed, resulting in a reduction of the average temperature of
the critical areas up to 300 K. This improvement prevents the anchoring of the accretion layer over
the port plates and the steel plate from being attacked by the copper.
... CHD is a multifactorial disease related to genetic and environmental factors [10]. The causes of birth defects have been widely discussed, but have not been fully elucidated [12]. By identifying the source of the defect, the defect rate could be reduced or eliminated [12]. ...
... The causes of birth defects have been widely discussed, but have not been fully elucidated [12]. By identifying the source of the defect, the defect rate could be reduced or eliminated [12]. ...
Background: NKX2.5 is a transcription factor that plays a key role in cardiovascular growth and development. Many independent studies have been conducted to investigate the association between the single nucleotide polymorphism 606G>C (rs3729753) in the coding region of NKX2.5 and congenital heart disease (CHD), although the results were inconsistent. This study aimed to reveal as much as possible the relationship between NKX2.5 single nucleotide polymorphism 606G>C and the risk of congenital heart disease in the Chinese population through meta-analysis.
Methods and Results: After retrieving related articles in PubMed, MEDLINE, EMBASE, Web of science, Coherane, China National Knowledge Infrastructure (CNKI), Wanfang DATA, VIP database until Aug 2021, a total of 8 studies were finally included. Then, we merged the qualified research data into allele model, dominant model, recessive model, heterozygous model, homozygous model, additive model respectively. Overall meta-analysis results showed that 606G>C was not associated with congenital heart disease of the Chinese population in any model. Also, subgroup analysis based on congenital heart disease type gave the same negative result. Sensitivity analysis showed that there was no significant correlation after the deletion of each study. The results were negative and the heterogeneity was not significant.
Conclusion: Our results show that NKX2-5 single nucleotide polymorphism 606G> C may not lead to the risk of congenital heart disease in Chinese.
... The chemical composition of the material before the carburizing and quenching treatment is reported in Table 1 which measured by a spectrometer (OBLF GS1000, Witten, Germany). The small differences in the case hardening process may cause large differences in heavy-duty industry performance [3,14], so the same case hardening process used for a real sun gear in a wind turbine gearbox has been adopted. The schematic diagram showing the methodology of this work was drawn in Figure 1. ...
In this work, the nanomechanical properties involving the indentation size effect (ISE) and yield strength of a surface-modified layer of 18CrNiMo7-6 steel after case hardening were investigated via nanoindentation experiments. The experimental results showed that the hardness increased with an increase in strain rate; the contact stiffness versus indentation depth curves take the form of upper convexity due to residual compressive stress relaxation. On the basis of the Ruiz-Moreno model, a modified model considering the cutoff parameter as a function of indentation depth was proposed. This model was able to better describe the ISE of the surface-modified layer. With the Hough transform error angle of 0.1° as the critical value (h0.1° is the corresponding depth), when h > h0.1°, the yield strength calculated by the Ma model started to disperse at the depth of h0.1°. These results provide useful insight into the local mechanical properties of 18CrNiMo7-6 steel after carburizing and quenching treatment.
