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Search Results: 1 - 10 of 118019 matches for " T. Haga "
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Development of a twin roll caster for light metals
T. Haga
Journal of Achievements in Materials and Manufacturing Engineering , 2010,
Abstract: Purpose: Purpose of this paper is to show the development of a twin roll caster for aluminium alloy. One of the developments was the increase of the roll speed. The increase of the roll speed was essential to improve the low productivity of the twin roll caster. Limitation of the alloys, which can be cast into the strip, could be enlarged by the method to increase the roll speed. The method to increase the roll speed was useful to increase the cooling rate of the cast strip. The devices to increase the roll speed were shown in this paper. Other development was invention of the twin roll caster to cast clad strip. The twin roll casters to cast two layers clad strip, three layers clad strip and five layers clad strip were invented.Design/methodology/approach: Increase of roll speed was attained by the use of a copper roll and a nozzle, operation of the low temperature casting and non-use of parting material. A scraper was adopted to the twin roll caster for clad strip to prevent the mixture of the molten metals and to control the surface condition. The devices to increase the roll speed were useful for the roll caster to cast clad strip.Findings: The aluminium alloy strip could be cast at the speeds up to 90 m/min. The aluminium alloy which has wide freezing zone like Al-25%Si could be cast into the strip. Two layers, three layers and five layers of clad strips could be cast.Research limitations/implications: The roll casters were laboratory size. Therefore, it was not clear of the ability of the casting of the long size and wide size strips.Practical implications: The productivity of aluminium alloy strip is increased. The property of the aluminium alloy strip is improved. The aluminium alloy, which was too brittle to be formed into the plate, will be cast into strip directly from melt. The process and energy to make the brazing sheet will be saved by the roll caster of the present study.Originality/value: The invented roll casters, devices for casting and properties of the cast strips are original.
High speed roll casting of Mg alloy strip by a vertical type twin roll caster
T. Haga,H. Watari,S. Kumai
Journal of Achievements in Materials and Manufacturing Engineering , 2006,
Abstract: Purpose: The possibility of high speed roll casting of AZ31, AM60 and AZ91 was investigated. Warm deep drawing of roll cast magnesium alloy was operated. and formability of roll cast magnesium strip was cleared.Design/methodology/approach: A vertical type high speed twin roll caster was used. The roll casting was operated in the air atmosphere. The casting speed was from 60 m/min up to 180 m/min. Low temperature casting was adopted to realize high speed casting.Findings: Strip thinner 3 mm with 100 width could be cast continuously. The casting ability became better with increasing content of Al. Roll cast Mg alloy strips could be hot-rolled down to 0.5 mm. AZ31 as-cast strip could be thinner down to 0.5 mm only by three times of hot rolling. Deep drawing was operated with three kinds of Mg alloy at 250°C, and LDR value was larger than 2.0. It was shown that deep drawing of AZ91 alloy for casting was possible.Research limitations/implications: There was tendency that cracks occurred at the center in the thickness direction as Al content increased.Practical implications: Sheet metal forming of magnesium alloy with high content Al can be realized.Originality/value: It was shown that possibility of high speed roll casting of magnesium alloy, and warm deep drawing of roll cast AZ91 strip.
Micro-forming of Al-Si foil
T. Haga,K. Inoue,H.Watari
Journal of Achievements in Materials and Manufacturing Engineering , 2010,
Abstract: Purpose: of this paper is as below. The investigation of the ability of the cold micro-forming of non-metallic glass was purpose. The grain of the rapidly solidified aluminium alloy became fine. The aluminium alloy foil with fine grain was used, and the investigation of the micro-formability of this alloy was investigated. Moreover, increase of the forming speed was investigated. The increase of the forming speed was purpose of this study, too.Design/methodology/approach: The nozzle pressing melt spinning method was used to attain the rapid solidification of the non-metallic grass. The Al-14mass%Si, which is hyper eutectic but is close to eutectic, was used. The roll contact surface was formed by V-groove. The cold rolling was adopted for forming. The V-groove was machined at the roll surface. The micro-forming was operated at the cold work. Findings: Micro-forming of the crystal aluminium alloy was able by the cold work. The forming speed was 0.04S to form 10 μm height. The forming speed could be drastically increased. Research limitations/implications: The angle of the V-groove, which was used in the present study, was only 60 degrees. The effect of the groove angle on the protrusion-height was not clear. The used material was only the Al-14mass%Si. Relationship between the material and protrusion-height was not clear.Practical implications: The die for the micro-forming of the resin could be made from economy material by the conventional cold rolling process at short time. Therefore, the mass production of the economy die for resin may be obtained.Originality/value: The micro-forming of the rapidly solidified non-metallic glass by cold work was original.
Roll caster for the three-layer clad-strip
R. Nakamura,T. Yamabayashi,T. Haga,S. Kumai
Archives of Materials Science and Engineering , 2010,
Abstract: Purpose: of this paper is to show the characteristics of two kinds of roll casters for three-layer clad strip of aluminium alloys. Moreover, the characteristics of these twin roll casters were compeered with the early type of roll casters for clad strip.Design/methodology/approach: Design was tried to attain the fabrication of the roll casters to cast the three-layers-clad-strip. One caster was an unequal diameter roll caster equipped with a scraper. The scraper was adopted to prevent the mixture of different kinds of melts of the alloys. The scraper was used to cast the clad strip with clear interfaces between each strip. The other caster was a tandem type roll caster assembled from two vertical type twin roll casters. A vertical type of twin roll was mounted on the other vertical type of a twin roll caster.Findings: Three layers of clad strips could be cast by two kinds of the roll casters developed in the present study. The casting speed was 20 m/min. This speed was much higher at the conventional twin roll caster for the aluminium alloys. Each strip of three layers clad strip was connected strictly. The element of clad strip did not peel at the interface by continuous bending. The as-cast clad strip could be cold-rolled. The element of alloys did not mix at the connecting interface of the strips. The casting conditions which affected the connecting of the strips and condition of interface were investigated and shown in this paper.Research limitations/implications: The width of the strip was from 30 mm to 50 mm. The casting of the wide strip was not investigated. The alloy used in the present study was only aluminium alloys. The length of the cast strip was 3 m. The thickness of element strip was from 0.8 mm to 1.5 mm. The difference of the melting temperature of the alloys was within 50°C. The number of the layers was less than three layers.Practical implications: The roll caster invented in the present study can be used for the fabrication of the clad strip. The clad strip is, for example, used for the brazing sheet of the radiator for the automotive industry.Originality/value: There was not a report concerning the roll caster for three layers clad strip. The roll casters for clad strips shown in this paper were of an original process. Especially, the use of the scraper in the roll casting was original.
Vocabulary Game Using Augmented Reality—Expressing Elements in Virtual World with Objects in Real World  [PDF]
Kong Yang, Haga Hirohide
Open Journal of Social Sciences (JSS) , 2015, DOI: 10.4236/jss.2015.32005
Abstract:

The purpose of this study is to express elements in virtual world with logical constraints using objects in real world with physical constraints. As an example to achieve this purpose, this paper presents an English vocabulary game utilizing game engine Unity and programming language C# along with ARTool Kit, a software library for building Augmented Reality (AR) applications.This game, designed for the purpose of education by aiming at helping students memorize English vocabulary, can be classified as a serious game. Watching the question provided by the game program on the screen, which designates alphabets player can use to assemble into a word, the player arranges the cardboard boxes with alphabets on it in the real world. Through the camera, the AR program detects the arrangement and position of the markers which are the alphabets on the boxes. Then, the game program judges whether the arrangement is the correct English word. This game expresses the game objects in the game program using cardboard boxes in the real world.

Code Clone Detection Method Based on the Combination of Tree-Based and Token-Based Methods  [PDF]
Ryota Ami, Hirohide Haga
Journal of Software Engineering and Applications (JSEA) , 2017, DOI: 10.4236/jsea.2017.1013051
Abstract: This article proposes the high-speed and high-accuracy code clone detection method based on the combination of tree-based and token-based methods. Existence of duplicated program codes, called code clone, is one of the main factors that reduces the quality and maintainability of software. If one code fragment contains faults (bugs) and they are copied and modified to other locations, it is necessary to correct all of them. But it is not easy to find all code clones in large and complex software. Much research efforts have been done for code clone detection. There are mainly two methods for code clone detection. One is token-based and the other is tree-based method. Token-based method is fast and requires less resources. However it cannot detect all kinds of code clones. Tree-based method can detect all kinds of code clones, but it is slow and requires much computing resources. In this paper combination of these two methods was proposed to improve the efficiency and accuracy of detecting code clones. Firstly some candidates of code clones will be extracted by token-based method that is fast and lightweight. Then selected candidates will be checked more precisely by using tree-based method that can find all kinds of code clones. The prototype system was developed. This system accepts source code and tokenizes it in the first step. Then token-based method is applied to this token sequence to find candidates of code clones. After extracting several candidates, selected source codes will be converted into abstract syntax tree (AST) for applying tree-based method. Some sample source codes were used to evaluate the proposed method. This evaluation proved the improvement of efficiency and precision of code clones detecting.
Past, Present and Future of Process Control at Xstrata Nikkelverk
T.A. Hauge,R. L?kling,S. Haga
Modeling, Identification and Control , 2009, DOI: 10.4173/mic.2009.3.6
Abstract: MIC celebrates its 30th anniversary in 2009 and Xstrata Nikkelverk celebrates its 100th anniversary in 2010. Both anniversaries are certainly worth celebrating and with this article Xstrata Nikkelverk salutes MIC at this special occasion.
Casting of aluminum alloy strip using an unequal diameter twin roll caster
T. Haga,H. Inui,H. Watari,S. Kumai
Archives of Materials Science and Engineering , 2008,
Abstract: Purpose: of this paper is to clear the property and ability of an unequal diameter twin roll caster to castcommercial size strip. Therefore, 400mm-width strip was cast as first step. Surface-condition, microstructure andmechanical property of the strip was investigated.Design/methodology/approach: Method used in the present study was an unequal diameter twin roll caster.This method was devised to realize easy operation of the twin roll casting and increase of casting speed.Findings: are that 400-width-strip of 3084, 5182 and 6022 could be cast at speed of 20 m/min. This strip wasabout 4 mm-thick. There were some defects on the surface. As cast strip could be cold-rolled down to sheetof 1 mm-thick. 180 degrees bending test was operated on the 6022 sheet after T4 heat treatment. Crack did notoccurred at the outer surface when strip was bent at width-direction.Research limitations/implications: is that the quantity of the melt was 21kg and investigation of theproperties was not enough for practical use. The larger weight of melt must be cast for production.Practical implications: are as below. The 400mm-width strip can be cast easily by the unequal diameter twinroll caster. This caster can be adapted to 3083, 5182 and 6022.Originality/value: as below. The economy sheet with 400mm width can be produced by the unequal diameter twinroll caster. 3083, 5182 and 6022 can be cast at the speed of 20m/min. The thickness of the strip was about 4mm.
Clad strip casting by a twin roll caster
T. Haga,R. Nakamura,S. Kumai,H. Watari
Archives of Materials Science and Engineering , 2009,
Abstract: Purpose: Of this paper is to realize the casting of the clad strip by only one process. Therefore, the investigation of the ability of the casting of the clad strip by a vertical type twin roll caster was operated. The aim of the use of the twin roll caster to make clad strip was in the reduction of the production-energy of the clad strip.Design/methodology/approach: Used in the present study was a vertical type twin roll caster with the scriber. The scriber was used to prevent the mixture of the two kinds of the melts. The scriber was set at roll-bite, and the scriber contacted to the one of solidification layer. The melt was stopped by the scriber and the only the solidification layer was dragged by the roll.Findings: The clad strip with the clear interface could be by the vertical type twin roll caster with the scriber. The scriber was useful to drag only the solid and semisolid layer. The two kinds of strips were connected strictly at the interface of the clad strip. The clad strip was not broken at the interface by the continuous bending.Research limitations/implications: Are that 100 mm width-strip was cast in the present study. Ability of the clad strip that is wider than 100 mm was not clear. The control of the clad ratio was not investigated.Practical implications: The twin roll caster devised and investigated in this report is useful to cast clad strip like the brazing sheet for the radiator of the automobile.Originality/value: The vertical type twin roll cater to cast clad strip is original process. The scriber was used to prevent the mixture of the two kinds of melts. The scriber was not used in the previous research to cast clad strip at the twin roll caster, and use of the scriber was the first try.
Grooved roll for a high speed twin roll caster
T. Haga,K. Hirooka,H. Watari,S. Kumai
Archives of Materials Science and Engineering , 2008,
Abstract: Purpose: Purpose of this paper is investigation of the effect of roll-surface on the strip-surface. Improvement ofsmall cracks on the strip-surface was tried and effect of groove at the roll surface on the strip surface was shown.Design/methodology/approach: Method used in the present study was high speed twin roll caster withgrooved roll. Two kinds of grooves were used: one was parallel groove and the other was cross groove machinedby knurling and bite attached to a lathe.Findings: Findings of this research are that grooved roll was effective to eliminate the small cracks on the stripsurface. The contact condition between the roll and the melt became uniform by the small groove on the rollsurface. Contact area became small, and heat transfer between the melt and roll became small, too. As the result,chill structure did not become columnar, and crack did not occur. Groove pattern on the strip surface could beerased by the cold rolling.Research limitations/implications: Research limitation is that groove life could not be investigated.Practical implications: Practical implications are as below. The roll load was small and strip was not hot-rolledin a high speed twin roll caster. The grooved roll made strip-surface sound. Grooved 600mm width roll was tested,and usefulness of the grooved roll was shown.Originality/value: In the present study effect of the grooved roll on a high speed twin roll caster was investigated.
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