scholarly journals Thermal Stresses in the Wall Connections of Cast Grate Structures

2016 ◽  
Vol 16 (4) ◽  
pp. 11-16 ◽  
Author(s):  
A. Bajwoluk ◽  
P. Gutowski
Keyword(s):  
Heat Treatment ◽  
Cross Section ◽  
Hot Spots ◽  
Thermal Stresses ◽  
Cooling Process ◽  
Temperature Variations ◽  
Temperature Changes ◽  
Different Types ◽  
The Difference ◽  
The Impact

Abstract The purpose of this study was to establish a relationship between the type of wall connection used in the cast grates, which are part of the equipment operating in furnaces for heat treatment and thermal-chemical treatment, and stresses generated in these grates during the process of rapid cooling. The places where the grate walls are connected to each other are usually characterized by the thickness larger than the remaining parts of walls. Temperature variations in those places are responsible for the formation of hot spots, and in the hot spots temperature changes much more slowly. The type of wall connection shapes the temperature gradient in the joint cross-section, and hence also the value of thermal stresses generated during cooling. In this study, five different designs of the grates were compared; the difference in them was the type of the designed wall connection. The following design variants were adopted in the studies: X connections with and without holes, T connections with and without technological recesses, and R (ring) connection. Numerical analysis was performed to examine how the distribution of temperature changes in the initial phases of the cooling process. The obtained results served next as a tool in studies of the stress distribution in individual structures. The analysis were carried out by FEM in Midas NFX 2014 software. Based on the results obtained, the conclusions were drawn about the impact of different types of wall connections on the formation of thermal stresses in cast grates.

Heat Treatment Behavior of Tungsten Heavy Alloy

2006 ◽  
Vol 118 ◽  
pp. 35-40 ◽  
Author(s):  
Woon Hyung Baek ◽  
Moon Hee Hong ◽  
Eun Pyo Kim ◽  
Joon Woong Noh ◽  
Seong Lee ◽  
...  
Keyword(s):  
Heat Treatment ◽  
Dynamic Properties ◽  
Weight Percent ◽  
Matrix Phase ◽  
Heavy Alloy ◽  
Tungsten Heavy Alloy ◽  
Cyclic Heat Treatment ◽  
Cyclic Heat ◽  
The Difference ◽  
The Impact

This paper focuses on the variations of static and dynamic properties of tungsten heavy alloy with heat treatment. The matrix phase of 93W-4.9Ni-2.1Fe (weight percent) has been penetrated into W/W grain boundaries during a cyclic heat treatment which consists of repeated isothermal holdings at 1150 °C and water quenching between them. By applying the cyclic heat treatment, the impact energy of tungsten heavy alloy is increased about three times from 57 to 170 J. When the tungsten heavy alloy is cyclically heat treated at 1150 °C and then re-sintered at 1485 °C, W/matrix interface is changed from round to undulated shape. The irregularity of the interface is increased with increasing the number of heat treatment cycles. From the measurement of the residual stress of W grains by X-ray diffraction, it is found that the irregularity of the interface is closely related with strain energy stemmed from the difference of thermal expansion coefficient between W particles and matrix phase. From dynamic ballistic test, it is found that the tungsten heavy alloy with undulated W grains forms many narrow fracture bands which are preferential for the self sharpening effect, thus, for the improvement of the penetration performance.

scholarly journals An Analysis of Differences in the Role of Friendships and the School Class in Children’s Perceptions of Bullying in England and Ijime in Japan: A Translation and Expansion of Kanetsuna (2009)

2021 ◽  
Vol 18 (15) ◽  
pp. 8234
Author(s):  
Tomoyuki Kanetsuna ◽  
Peter K. Smith
Keyword(s):  
Secondary School ◽  
Comparative Study ◽  
English Translation ◽  
School Class ◽  
Friendship Formation ◽  
Different Types ◽  
The Difference ◽  
Perceptions Of Bullying ◽  
The Impact

This is an English translation with some expansion of the article originally published in Japanese as a university bulletin in 2009. Previous research has found both differences and similarities between ijime in Japan and bullying in England. Bullying is often by pupils in different classes or higher year groups whom the victim does not know very well; ijime is often by victims’ classmates whom the victim knows very well. However, it has not been shown whether these differences are found for all types of bullying, or how they relate to friendships generally and the impact of differing school systems. We aimed to see whether previously found differences between ijime and bullying could be replicated, and, if so, whether they held for six different types of victimization, and whether friendship characteristics were consistent with explaining why they occur. To investigate the role of friendships and their location, 1036 Japanese and 931 English secondary school pupils participated in a comparative study of perceptions of bullying and ijime. The previous differences were confirmed and found to hold irrespective of type of bullying. Japanese pupils mainly formed friendships on a class basis, English pupils on a broader basis including pupils in different years. In school, English pupils spent much time in the playground with their friends and saw this as a likely venue for bullying, whereas Japanese pupils spent more time in the classroom and saw this as a likely venue for ijime. The difference in friendship formation, together with differences in the organization of class-based teaching in the two countries, are hypothesized to play a significant role in explaining some differences between bullying and ijime.

scholarly journals Nitric oxide and superoxide transport in a cross section of the rat outer medulla. I. Effects of low medullary oxygen tension

2010 ◽  
Vol 299 (3) ◽  
pp. F616-F633 ◽  
Author(s):  
Aurélie Edwards ◽  
Anita T. Layton
Keyword(s):  
Nitric Oxide ◽  
Cross Section ◽  
Vascular Bundle ◽  
Fluid Model ◽  
Vascular Bundles ◽  
Concentration Gradients ◽  
Outer Medulla ◽  
Vasa Recta ◽  
The Difference ◽  
The Impact

To examine the impact of the complex radial organization of the rat outer medulla (OM) on the distribution of nitric oxide (NO), superoxide (O2−) and total peroxynitrite (ONOO), we developed a mathematical model that simulates the transport of those species in a cross section of the rat OM. To simulate the preferential interactions among tubules and vessels that arise from their relative radial positions in the OM, we adopted the region-based approach developed by Layton and Layton ( Am J Physiol Renal Physiol 289: F1346–F1366, 2005). In that approach, the structural organization of the OM is represented by means of four concentric regions centered on a vascular bundle. The model predicts the concentrations of NO, O2−, and ONOO in the tubular and vascular lumen, epithelial and endothelial cells, red blood cells (RBCs), and interstitial fluid. Model results suggest that the large gradients in Po2 from the core of the vascular bundle toward its periphery, which stem from the segregation of O2-supplying descending vasa recta (DVR) within the vascular bundles, in turn generate steep radial NO and O2− concentration gradients, since the synthesis of both solutes is O2 dependent. Without the rate-limiting effects of O2, NO concentration would be lowest in the vascular bundle core, that is, the region with the highest density of RBCs, which act as a sink for NO. Our results also suggest that, under basal conditions, the difference in NO concentrations between DVR that reach into the inner medulla and those that turn within the OM should lead to differences in vasodilation and preferentially increase blood flow to the inner medulla.

A Note on the Determination of the Thermal Stresses in Multi-Metal Beams Subjected to Temperature Variations

1991 ◽  
Vol 113 (4) ◽  
pp. 425-427 ◽  
Author(s):  
A. O. Cifuentes
Keyword(s):  
Linear System ◽  
Thermal Stresses ◽  
Closed Form Solution ◽  
Technical Note ◽  
Form Solution ◽  
System Of Equations ◽  
Temperature Variations ◽  
Temperature Changes ◽  
Linear System Of Equations

This technical note shows that the determination of the stresses induced in multi-metal beams by temperature changes reduces to solving a linear system of equations. This system of equations has a very particular structure that allows one to obtain a closed form solution easily.

scholarly journals The Effect of Pallet Component Geometry on Temperature Gradient During Cooling

2015 ◽  
Vol 15 (1) ◽  
pp. 5-8 ◽  
Author(s):  
A. Bajwoluk ◽  
P. Gutowski
Keyword(s):  
Heat Treatment ◽  
Temperature Distribution ◽  
Temperature Gradient ◽  
Thermal Stresses ◽  
Rapid Cooling ◽  
The Impact

Abstract The paper discusses the impact of the geometry of foundry pallet components on the value of temperature gradient on the wall crosssection during heat treatment. The gradient is one of the most important factors determining the distribution of thermal stresses in these items. Analysis of quantitative simulation was carried out to detect possible effect of the type of connection between pallet walls and thickness of these walls (ribs) on the interior temperature distribution during rapid cooling. The analysis was performed for five basic designs of wall connections used in pallets. Basing on the results obtained, the conclusions were drawn on the best connection between the ribs in foundry pallets.

scholarly journals G. E. LESSING'S LAOCOON: THE POTENTIAL OF THE SEMANTIC APPROACH

2020 ◽  
pp. 23-27
Author(s):  
H. D. Mylenka
Keyword(s):  
Large Array ◽  
Semantic Approach ◽  
Key Concepts ◽  
Different Types ◽  
The Difference ◽  
Organic Combination ◽  
The Impact ◽  
Semantic Aspect ◽  
Theoretical Developments

Despite the large array of studies of the theoretical heritage of the German enlightener, this aspect has been most fully developed in the works of I.G. Gerder (article "Critical forests"), R. Ingarden (monograph "Research in aesthetics") and E. Basin (monograph "Art and communication"). In updating the potential of the semantic problematic of Laocoon, considerable assistance is provided by the recourse to studies in which the fruitfulness and relevance of this aspect of the Lessing tract is emphasized to one degree or another. There is an attempt to analyze, in one theoretical space, works on Lessing theory of signs. In order to identify the essence of the disagreement between I.G. Gerder and G.E. Lessing in the field of establishing boundaries between the kinds of art, special attention is paid to the consideration of Gerder concept of comparative analysis of painting, music and poetry, which is based on the difference of their ways of influence on the recipient – "in space", "in time "and" by force". In the process of analyzing Gerder's reflections, not only his critical attitude to the theory of signs developed by Lessing was considered, but also an attempt by the opponent of "Laokoon" author to justify the use of key concepts of metaphysics to compare the impact of different kinds of art. When comparing the views of E. Basin and R. Ingarden on the semantic aspect of "Laocoon", the debatable nature of their judgments about the characterization of the characters used in poetry by Lessing is identified. In addition, the article analyzes Lessing's thinking about the possibility of connecting different types of art, the organic combination of which depends on the specifics of the signs used by one or the other art, as well as emphasizes the productivity of the German thinker's idea. This aspect is revealed not only through the analysis of "Laokoon" in the works of E. Basin and R. Ingarden, but also by turning to the theoretical developments of E. Cassirer, B. Balash, A. Vartanova. Thus, the study of the semantic issues of Laokoon has shown the prominence of its conceptual landmarks for theoretical search, both in the field of aesthetics and art.

scholarly journals Impact of Improved Chickpea Cultivation on Profitability and Livelihood of Farmers in Drought-Prone Areas of Bangladesh

2020 ◽  
Vol 18 (1) ◽  
pp. 129-142
Author(s):  
SC Sharna ◽  
M Kamruzzaman ◽  
ST Siddique
Keyword(s):  
Social Capital ◽  
International Development ◽  
Cost Ratio ◽  
Sustainable Livelihood ◽  
Local Varieties ◽  
Benefit Cost Ratio ◽  
Different Types ◽  
The Difference ◽  
Benefit Cost ◽  
The Impact

The cultivation of improved chickpea varieties has been increasing over time that kicks off the local varieties from the farmer’s field. Up-to-date socio-economic information regarding this issue is scanty in Bangladesh. That is why we analyze the profitability of improved chickpea variety and assess the impact of its cultivation on the livelihood of chickpea farmers in the high Barind region of Bangladesh. The values of benefit-cost ratio depict that the improved variety is more profitable in comparison to local chickpea variety; specifically, the benefit-cost ratio (BCR) of improved chickpea production is 1.87, while it is only 1.66 for local chickpea. To understand the wellbeing of chickpea farmers, the multidimensional livelihood index (MLI) following sustainable livelihood framework of the Department for International Development (DFID) is used, which constitutes the asset pentagon of five capitals namely human, physical, natural, financial and social capital. The MLI of improved and local chickpea growers are 0.51 and 0.39 respectively which belong in the middle livelihood category. Meanwhile, the MLI reflects that the improved variety cultivars are in a better livelihood condition than the local variety growers. Among all the five capitals of the MLI, the difference between these two groups is the largest in the case of social capital followed by financial capital. Since both groups have achieved far less MLI values than 1, the recommendation is therefore to ensure different types of facilities for the development of people of high Barind tract as well as increasing the production of improved chickpea. SAARC J. Agri., 18(1): 129-142 (2020)

scholarly journals Retention of Approximal Guiding Plane Surfaces in Removable Partial Skeletal Prosthesis

2018 ◽  
Vol 6 (6) ◽  
pp. 1120-1125 ◽  
Author(s):  
Blagoja Dastevski ◽  
Aneta Mijoska ◽  
Biljana Kapusevska ◽  
Nikola Gigovski ◽  
Oliver Dimitrovski ◽  
...  
Keyword(s):  
Zero Point ◽  
Retention Force ◽  
Zero Position ◽  
Different Types ◽  
Kolmogorov Smirnov ◽  
Natural Teeth ◽  
The Difference ◽  
Composite Inlays ◽  
The Impact ◽  
Approximal Surfaces

BACKGROUND: The morphology of the retention tooth often does not correspond with the required design; hence there is often an indication for enamel recontouring or other restorative procedures.AIM: The study aimed to determine the impact of changing the path of insertion of the prosthesis by reshaping the anatomical and morphological structures of the natural teeth predetermined for the retention of the prosthesis.MATERIAL AND METHODS: The group of 40 patients with Class II, Subclass 1 according to Kennedy was formed, and 120 approximal surfaces of retention teeth were obtained. Two different types of prostheses were made on the models: one group in the zero point position of the model, and another group in the zero position of the model, with changing of the direction of input at an angle of 2˚.RESULTS: The difference between the established and theoretical normal distribution of frequencies was tested with the Kolmogorov-Smirnov and Lilliefors tests (r < 0.10; r < 0.01). The first group showed a retention force of 0.08 N. In the second group the retention force was 0.94 N.CONCLUSION: It could be concluded that the change in the path of insertion of the dental prosthesis with conservative restorations as composite inlays, as well as the accurate extension of the prosthesis onto guiding plane surfaces, will undoubtedly increase the retention force of the prosthesis.

scholarly journals Study on the Impact of Thermal Agitation on Doppler Coefficient in Epithermal Range for Gd-Bearing Fuel

2016 ◽  
Vol 2016 ◽  
pp. 1-7
Author(s):  
Satoshi Takeda ◽  
Satoshi Ino ◽  
Kazuhiro Wada ◽  
Michitaka Ono ◽  
Takanori Kitada
Keyword(s):  
Cross Section ◽  
Capture Cross Section ◽  
Sensitivity Coefficient ◽  
Capture Cross ◽  
Multiplication Factor ◽  
Fuel System ◽  
Thermal Agitation ◽  
Similar Tendency ◽  
The Difference ◽  
The Impact

The impact of thermal agitation on Doppler coefficient for Gd-bearing fuel was analyzed. It was found through the analysis that the impact increases when a small amount of Gd2O3is added to pure UO2fuel although the impact decreases for a large amount of Gd2O3. This tendency was discussed with the usage of simplified expression for the difference of Doppler coefficient. The simplified expression was used to consider the tendency, and it was revealed that the tendency mainly comes from the rapid decrement of multiplication factor and the relatively slow decrement of the magnitude of sensitivity coefficient of U-238 capture cross section at low Gd2O3concentration. Similar tendency which shows a maximum impact on Doppler coefficient at interior concentration is expected for other UO2fuel with a slight content of strong absorber. This indicates that Doppler coefficient of UO2fuel system with low content of strong absorber should be analyzed carefully by considering thermal agitation in epithermal range.

scholarly journals Analysis of Thermal Stresses and Strains Developing during the Heat Treatment of Windmill Shaft

2017 ◽  
Vol 62 (2) ◽  
pp. 459-471 ◽  
Author(s):  
A. Cebo-Rudnicka ◽  
Z. Malinowski ◽  
T. Telejko
Keyword(s):  
Heat Treatment ◽  
Stress Field ◽  
Thermal Stresses ◽  
Stress Fields ◽  
Axially Symmetric ◽  
The Finite Element Method ◽  
Temperature Changes ◽  
Incremental Method ◽  
Heating And Cooling ◽  
The Mathematical Model

AbstractIn the paper the results of evaluation of the temperature and stress fields during four cycles of the heat treatment process of the windmill shaft has been presented. The temperature field has been calculated from the solution to the heat conduction equation over the whole heat treatment cycles of the windmill shaft. To calculate the stress field an incremental method has been used. The relations between stresses and strains have been described by Prandtl-Reuss equation for the elastic-plastic body. In order to determine the changes in the temperature and stress fields during heat treatment of the windmill shaft self-developed software utilizing the Finite Element Method has been used. This software can also be used to calculate temperature changes and stress field in ingots and other axially symmetric products. In the mathematical model of heating and cooling of the shaft maximum values of the strains have been determined, which allowed to avoid the crack formation. The critical values of strains have been determined by using modified Rice and Tracy criterion.

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