Repair Welding of Crane Wheels in Steelworks Smederevo

2016 ◽  
Vol 1138 ◽  
pp. 180-185 ◽  
Author(s):  
Drakče Tanasković ◽  
Branislav Đorđević ◽  
Mihajlo Aranđelović ◽  
Simon Sedmak ◽  
Aleksandar Sedmak ◽  
...  

Comparative analysis of a repaired and a new crane wheel, was performed in Steelworks Smederevo, including an economic analysis and technological procedures. The repair procedure for a crane wheel is presented, along with the selection of filler materials, as well as testing of mechanical properties performed on samples taken from hard faced welds. The advantages of repair techniques compared to the manufacturing of a new wheel are shown, but also the flaws that may affect the worklife and integrity of wear-damaged elements and components.

2010 ◽  
Vol 72 ◽  
pp. 46-52 ◽  
Author(s):  
Laurent Royer ◽  
Stéphane Mathieu ◽  
Christophe Liebaut ◽  
Pierre Steinmetz

For energy production and also for the glass industry, finding new refractory alloys which could permit to increase the process temperatures to 1200°C or more is a permanent challenge. Chromium base alloys can be good candidates, considering the melting point of Cr itself, and also its low corrosion rate in molten glass. Two families of alloys have been studied for this purpose, Cr-Mo-W and Cr-Ta-X alloys (X= Mo, Si..). A finer selection of compositions has been done, to optimize their chemical and mechanical properties. Kinetics of HT oxidation by air, of corrosion by molten glass and also creep properties of several alloys have been measured up to 1250°C. The results obtained with the best alloys (Cr-Ta base) give positive indications as regards the possibility of their industrial use.


2021 ◽  
Vol 13 (15) ◽  
pp. 8164
Author(s):  
Brian E. Bautista ◽  
Lessandro E. O. Garciano ◽  
Luis F. Lopez

There are limited published studies related to the mechanical properties of bamboo species in the Philippines. In this study, the shear strength properties of some economically viable bamboo species in the Philippines were properly characterized based on 220 shear test results. The rationales of selecting this mechanical property are the following: (1) Shear strength, parallel to the fiber, has the highest variability among the mechanical properties; and (2) Shear is one of the governing forces on joint connections, and such connections are the points of failure on bamboo structures when subjected to extreme loading conditions. ISO 22157-1 (2017) test protocol for shear was used for all tests. The results showed that Bambusa blumeana has the highest average shear strength, followed by Gigantochloa apus, Dendrocalamus asper, Bambusa philippinensis, and Bambusa vulgaris. However, comparative analysis, using One-way ANOVA, showed that shear strength values among these bamboo species have significant differences statistically. A linear regression model is also established to estimate the shear strength of bamboo from the physical properties. Characteristic shear strength is also determined using ISO 12122-1 (2014) for future design reference.


Helia ◽  
2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Kateryna Vasylkovska ◽  
Olha Andriienko ◽  
Oleksii Vasylkovskyi ◽  
Andrii Andriienko ◽  
Popov Volodymyr ◽  
...  

Abstract The analysis of the production and yield of sunflower seeds in Ukraine for the period from 2000 to 2019 was conducted in the article. The comparative analysis of the gross harvest of sunflower seeds and the export of sunflower oil for the years under research was carried out. The dependence of exports on gross harvest was revealed and its share was calculated. It was determined that the export of sunflower oil has increased over the years under research, which indicates a significant Ukraine’s export potential. It was found that the increase in the share of exports by 15.9% was made possible by a qualitative change in yield, that was ensured by the changes in the cultivation technology and by the selection of sunflower hybrids that are better adapted to climate changes. The recommendations for further improvement of cultivation technology in connection with climate change in order to further increase yields and the export potential of Ukraine were given.


2021 ◽  
Vol 12 (2) ◽  
pp. 26
Author(s):  
Sebastian Wilk ◽  
Aleksandra Benko

Biopolymers formed into a fibrous morphology through electrospinning are of increasing interest in the field of biomedicine due to their intrinsic biocompatibility and biodegradability and their ability to be biomimetic to various fibrous structures present in animal tissues. However, their mechanical properties are often unsatisfactory and their processing may be troublesome. Thus, extensive research interest is focused on improving these qualities. This review article presents the selection of the recent advances in techniques aimed to improve the electrospinnability of various biopolymers (polysaccharides, polynucleotides, peptides, and phospholipids). The electrospinning of single materials, and the variety of co-polymers, with and without additives, is covered. Additionally, various crosslinking strategies are presented. Examples of cytocompatibility, biocompatibility, and antimicrobial properties are analyzed. Special attention is given to whey protein isolate as an example of a novel, promising, green material with good potential in the field of biomedicine. This review ends with a brief summary and outlook for the biomedical applicability of electrospinnable biopolymers.


Polymers ◽  
2021 ◽  
Vol 13 (13) ◽  
pp. 2220
Author(s):  
Zaida Ortega ◽  
Francisco Romero ◽  
Rubén Paz ◽  
Luis Suárez ◽  
Antonio Nizardo Benítez ◽  
...  

This paper compares the mechanical properties of different natural fiber composites produced by rotational molding as a way of waste valorization from campaigns to control invasive plant species in Macaronesia. Rotomolded parts produced with polymeric matrices (polyethylene) and filled with up to 20% by weight of cellulosic fibers obtained from Arundo donax L., Pennisetum setaceum, and Ricinus communis plants were characterized in terms of tensile, flexural, and impact strength. It was found that the sieving of natural fibers allowed for their introduction in higher loadings, from 10 (for un-sieved material) to 20%; fiber size greatly affected the mechanical properties of the final parts, although some combinations were proven not to reduce the mechanical properties of the neat resin. This study is a first approach to the valorization of residues obtained from periodic campaigns of the control of invasive species performed by public authorities, usually at the local level. It is important to highlight that the main objective of this research did not focus on economically profitable activity; instead, it was focused on the reduction of wastes to be disposed from ecosystem maintenance actions and the investment of potential income into preservation policies.


2010 ◽  
Vol 123-125 ◽  
pp. 1031-1034 ◽  
Author(s):  
Sandhyarani Biswas ◽  
Alok Satapathy ◽  
Amar Patnaik

In order to obtain the favoured material properties for a particular application, it is important to know how the material performance changes with the filler content under given loading conditions. In this study, a series of bamboo fiber reinforced epoxy composites are fabricated using conventional filler (aluminium oxide (Al2O3) and silicon carbide (SiC) and industrial wastes (red mud and copper slag) particles as filler materials. By incorporating the chosen particulate fillers into the bamboo-fiber reinforced epoxy, synergistic effects, as expected are achieved in the form of modified mechanical properties. Inclusion of fiber in neat epoxy improved the load bearing capacity (tensile strength) and the ability to withstand bending (flexural strength) of the composites. But with the incorporation of particulate fillers, the tensile strengths of the composites are found to be decreasing in most of the cases. Among the particulate filled bamboo-epoxy composites, least value of void content are recorded for composites with silicon carbide filling and for the composites with glass fiber reinforcement minimum void fraction is noted for red mud filling. The effects of these four different ceramics on the mechanical properties of bamboo- epoxy composites are investigated and the conclusions drawn from the above investigation are discussed.


2015 ◽  
Vol 40 (3) ◽  
pp. 234-238 ◽  
Author(s):  
R. Haddad ◽  
T. Peltz ◽  
N. Bertollo ◽  
W. R. Walsh ◽  
S. Nicklin

Multiple-strand repair techniques are commonly used to repair cut flexor tendons to achieve initial biomechanical strength. Looped sutures achieve multiple strands with fewer passes and less technical complexity. Their biomechanical performance in comparison with an equivalent repair using a single-stranded suture is uncertain. This study examined the mechanical properties of double-stranded loops of 3-0 and 4-0 braided polyester (Ticron) and polypropylene monofilament (Prolene). Double loops were generally less than twice the strength of a single loop. Ticron and Prolene had the same strengths, but Ticron was stiffer. The 4-0 double loops had significantly higher stiffness than 3-0 single loops. Increasing the size of sutures had a larger relative effect on strength than using a double-stranded suture. However, a double-strand loop had a larger effect on increasing stiffness than using a single suture of a larger equivalent size. Looped suture repairs should be compared with standard techniques using a thicker single suture.


2003 ◽  
Vol 11 (3) ◽  
pp. 162-167 ◽  
Author(s):  
Linda Wang ◽  
Paulo Henrique Perlatti D'Alpino ◽  
Lawrence Gonzaga Lopes ◽  
José Carlos Pereira

A wide variety of dental products that are launched on the market becomes the correct selection of these materials a difficult task. Although the mechanical properties do not necessarily represent their actual clinical performance, they are used to guide the effects of changes in their composition or processing on these properties. Also, these tests might help somehow the clinician to choose once comparisons between former formulations and new ones, as well as, with the leading brand, are highlighted by manufactures. This paper presents a review of the most important laboratory tests. In this manner, the knowledge of these tests will provide a critical opinion related to the properties of different dental materials.


2015 ◽  
Vol 57 (4) ◽  
pp. 224-232
Author(s):  
Jarosław Siwiński ◽  
Katarzyna Kubiak ◽  
Miłosz Tkaczyk ◽  
Anna Mazur ◽  
Ryszard Rekucki

Abstract The study was conducted to perform a comparative analysis of the mechanical properties of wood samples derived from oaks in the Krotoszyn Plateau, which depend on the health state of the trees. Strength parameters of oak wood were calculated for selected diseased and healthy trees (according to the Roloff classification). The study was conducted by a modified method described in the standard Polish Norm PN EN 408+ A1: 2012. For testing, prior selection of wood samples showed that more wood samples of diseased trees compared with those of healthy oaks did not fulfil the Polish standard requirements. According to the method used, the average results of strength tests of timber structures from healthy oaks exhibited higher strength parameters than those of the diseased trees.


2016 ◽  
Vol 61 (1) ◽  
pp. 353-360 ◽  
Author(s):  
B. Dybowski ◽  
J. Szymszal ◽  
Ł. Poloczek ◽  
A. Kiełbus

Due to low density and good mechanical properties, aluminium alloys are widely applied in transportation industry. Moreover, they are characterized by the specific physical properties, such as high electrical conductivity. This led to application of the hypoeutectic Al-Si-Mg alloys in the power generation industry. Proper selection of the alloys chemical composition is an important stage in achievement of the demanded properties. The following paper presents results of the research on the influence of alloys chemical composition on their properties. It has been revealed that Si and Ti addition decreases electrical conductivity of the Al-Si-Mg alloys, while Na addition increases it. The mechanical properties of the investigated alloys are decreased by both silicon and iron presence. Sodium addition increases ductility of the Al-Si-Mg alloys.


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