WorldWideScience

Sample records for cast in place structures

  1. 29 CFR 1926.703 - Requirements for cast-in-place concrete.

    Science.gov (United States)

    2010-07-01

    ... 29 Labor 8 2010-07-01 2010-07-01 false Requirements for cast-in-place concrete. 1926.703 Section..., DEPARTMENT OF LABOR (CONTINUED) SAFETY AND HEALTH REGULATIONS FOR CONSTRUCTION Concrete and Masonry Construction § 1926.703 Requirements for cast-in-place concrete. (a) General requirements for formwork....

  2. Refreezing of cast-in-place piles under various engineering conditions

    Institute of Scientific and Technical Information of China (English)

    Lei Guo; QiHao Yu; XiaoNing Li; XinBin Wang; YongYu Yue

    2015-01-01

    In the construction of the Qinghai-Tibet Power Transmission Line (QTPTL), cast-in-place piles (CIPPs) are widely applied in areas with unfavorable geological conditions. The thermal regime around piles in permafrost regions greatly affects the stability of the towers as well as the operation of the QTPTL. The casting of piles will markedly affect the thermal regime of the surrounding permafrost because of the casting temperature and the hydration heat of cement. Based on the typical geological and engineering conditions along the QTPTL, thermal disturbance of a CIPP to surrounding permafrost under different casting seasons, pile depths, and casting temperatures were simulated. The results show that the casting season (summer versus winter) can influence the refreezing process of CIPPs, within the first 6 m of pile depth. Sixty days after being cast, CIPPs greater than 6 m in depth can be frozen regardless of which season they were cast, and the foundation could be refrozen after a cold season. Comparing the refreezing characteristics of CIPPs cast in different seasons also showed that, without considering the ground surface conditions, warm seasons are more suitable for casting piles. With the increase of pile depth, the thermal effect of a CIPP on the surrounding soil mainly expands vertically, while the lateral heat disturbance changes little. Deeper, longer CIPPs have better stability. The casting temperature clearly affects the thermal disturbance, and the radius of the melting circle increases with rising casting temperature. The optimal casting temperature is between 2 °C and 9 °C.

  3. Cast-in-place concrete thin-wall pipe pile as barrier for vibration isolation

    Institute of Scientific and Technical Information of China (English)

    张富有; 陈灿寿; 魏良甲; 张霆

    2008-01-01

    Three dimensional analysis was performed by regarding vibration isolation performance cast-in-place concrete thin-wall pipe pile (PCC) and using the finite element analysis software ANSYS. The ground vertical amplitude was analyzed behind the single row cast-in-place concrete thin-wall pipe pile after the source vibration, and the influencing factors were also studied. The results indicate that in the one time of wavelength before the barrier, the oscillation amplitude is weakened; meanwhile the range which covers 4 times wavelength behind the barrier has a good vibration isolation effect, when the distance is larger than the barrier latter 4 times wavelength vibration isolation expiration.

  4. GBF竹芯内模现浇空心楼盖结构施工技术%The construction technique of cast-in-place hollow floor structure of GBF internal model with bamboo core

    Institute of Scientific and Technical Information of China (English)

    江益珍

    2016-01-01

    GBF竹芯内模现浇空心楼盖技术是现浇混凝土楼盖体系一种新的形式,可以很好地满足开间跨度大及空间需求大的建筑工程。本文结合具体工程实例,对该施工技术在实际施工及应用过程中的控制要点进行分析探讨,为今后类似工程施工提供参考。%The construction technique of cast- in- place hollow floor structure of GBF internal model with bamboo core is a new form of cast-in-place concrete floor system,which can well meet the demand of large span construction projects. In this article,which combines with specific engineering example,the control points in the actual construction were analyzed and a reference for future similar projects was provided.

  5. Experimental Research on Large Diameter Cast-in-Place Piles Embedded in Rock

    Institute of Scientific and Technical Information of China (English)

    衡朝阳; 何满潮; 姚爱军

    2001-01-01

    This paper expatiated the field test of large diameter cast-in-place piles embedded in soft rock, including static loading test, high or low strain dynamic test, measurement of stresses and strains of pile body, and pressure measurements between pile tip and soft rock. The relative in-situ test problems are discussed. Based on the limit equilibrium theory and the load transfer equation, a synthesis method of analyzing the ultimate carrying capacity of single large diameter pile is put forward. The research results show that the key to determining the ultimate carrying capacity of single pile with a large diameter is the analysis of the intensity of soft rock.

  6. 浅谈现浇混凝土空心楼盖的设计%Discussion on the design of cast-in-place hollow section shaped floor

    Institute of Scientific and Technical Information of China (English)

    孙洪波

    2009-01-01

    介绍了现浇混凝土空心楼盖结构的优点,对现浇混凝土空心楼盖结构的主要技术内容及特点进行了分析,强调了构造设计在现浇混凝土空心楼盖设计中的重要性,以完善此结构的设计,从而推广该结构的应用.%The advantages of cast-in-place hollow section shaped floor were introduced, and the principal technical contents and charaetexistics of cast-in-place hollow section shaped floor structure were analyzed. The importance of structural design in cast-in-place hollow section ahapad floor was strengthened, so as to complete structural design and popularize the structure application.

  7. Field study of plastic tube cast-in-place concrete pile

    Institute of Scientific and Technical Information of China (English)

    陈永辉; 曹德洪; 王新泉; 杜海伟; 张霆

    2008-01-01

    The compositions, technical principles and construction equipments of a new piling method used for ground improvement plastic tube cast-in-place concrete pile were introduced. The results from static load tests on single piles with different forms of pile shoes and on their composite foundations were analyzed. The distribution patterns of axial force, shaft friction and toe resistance were studied based on the measurements taken from buried strain gauges. From the point of engineering application, the pile has merits in convenient quality control, high bearing capacity and reliable quality, showing higher reasonability, advancement and suitability than other ground improvement methods. The pile can be adopted properly to take place of ordinary ground improvement method, achieving greater economical and social benefits.

  8. 梁钢筋部分移置梁侧楼板的现浇混凝土框架抗震性能研究%Improvement of seismic performance of cast-in-place reinforced concrete frame structures with some of the beam reinforcements placed into the adjacent slabs

    Institute of Scientific and Technical Information of China (English)

    王依群; 韩鹏; 韩昀珈

    2012-01-01

    汶川地震中损坏的楼板与梁整体现浇的钢筋混凝土框架结构几乎全部是“强梁弱柱”型破坏,这是由于多年来建筑设计中,框架梁的钢筋配置过多和抗震设计规范中规定的框架柱相对于框架梁的受弯强度放大系数偏小。2010年颁布实施的《建筑抗震设计规范》(GB50011—2010)适当提高了该放大系数,但仍不能根本解决地震时柱先于梁破坏的问题。分析混凝土结构设计的全过程,发现“强梁弱柱”型破坏的主要原因,即该种结构的梁上部配置钢筋过多。对罕遇地震作用下减少梁上部钢筋的两个实际工程进行弹塑性时程计算,结果表明:减少梁上部钢筋可改善楼板与梁整体现浇混凝土框架结构的抗震性能,同时降低了造价,且方便施工。%Almost all of the damaged cast-in-place reinforced concrete frame structures in the Wenchan earthquake are in the form of strong-beam and weak-column mechanism damage Too much top-reinforcement than required at beam ends and too small moment amplification factor of the columns have caused “strong-beam and weak-column” damages. Code for seismic design of buildings GB 50011-2010 increased the moment amplification factor for columns, it is still not enough to stop the fact that columns are more prone to damage than beams. Elasto-plastic time-history analyses are conducted for two structures with reduced reinforcements in the upper part of the beams, subjected to rare earthquakes. The results show that the seismic performance of the cast-in-place reinforced concrete frame structures has been greatly improved and the construction costs reduced.

  9. Development of NZP ceramic based {open_quotes}cast-in-place{close_quotes} diesel engine port liners

    Energy Technology Data Exchange (ETDEWEB)

    Nagaswaran, R.; Limaye, S.Y.

    1996-02-01

    BSX (Ba{sub 1+x}Zr{sub 4}P{sub 6-2x}Si{sub 2x}O{sub 24}) and CSX (Ca{sub l-x}Sr{sub x}Zr{sub 4}P{sub 6}O{sub 24}) type NZP ceramics were fabricated and characterized for: (i) thermal properties viz., thermal conductivity, thermal expansion, thermal stability and thermal shock resistance; (ii) mechanical properties viz., flexure strength and elastic modulus; and (iii) microstructures. Results of these tests and analysis indicated that the BS-25 (x=0.25 in BSX) and CS-50 (x=0.50 in CSX) ceramics had the most desirable properties for casting metal with ceramic in place. Finite element analysis (FEA) of metal casting (with ceramic in place) was conducted to analyze thermomechanical stresses generated and determine material property requirements. Actual metal casting trials were also conducted to verify the results of finite element analysis. In initial trials, the ceramic cracked because of the large thermal expansion mismatch (hoop) stresses (predicted by FEA also). A process for introduction of a compliant layer between the metal and ceramic to alleviate such destructive stresses was developed. The compliant layer was successful in preventing cracking of either the ceramic or the metal. In addition to these achievements, pressure slip casting and gel-casting processes for fabrication of NZP components; and acoustic emission and ultrasonics-based NDE techniques for detection of microcracks and internal flaws, respectively, were successfully developed.

  10. Structure fields in the solidifying cast iron roll

    Directory of Open Access Journals (Sweden)

    W.S. Wołczyński

    2010-01-01

    Full Text Available Some properties of the rolls depend on the ratio of columnar structure area to equiaxed structure area created during roll solidification. The transition is fundamental phenomenon that can be apply to characterize massive cast iron rolls produced by the casting house. As the first step of simulation, a temperature field for solidifying cast iron roll was created. The convection in the liquid is not comprised since in the first approximation, the convection does not influence the studied occurrence of the (columnar to equiaxed grains transition in the roll. The obtained temperature field allows to study the dynamics of its behavior observed in the middle of the mould thickness. This midpoint of the mould thickness was treated as an operating point for the transition. A full accumulation of the heat in the mould was postulated for the transition. Thus, a plateau at the curve was observed at the midpoint. The range of the plateau existence corresponded to the incubation period , that appeared before fully equiaxed grains formation. At the second step of simulation, behavior of the thermal gradients field was studied. Three ranges within the filed were visible: EC→EC→EC→EC→(tTECtt↔RERCtt↔a/ for the formation of columnar structure (the C – zone: ( and 0>>T&0>>=−>−=REREttGttG.The columnar structure formation was significantly slowed down during incubation period. It resulted from a competition between columnar growth and equiaxed growth expected at that period of time. The 0≈=−=RERCttGttG relationship was postulated to correspond well with the critical thermal gradient, known in the Hunt’s theory. A simulation was performed for the cast iron rolls solidifying as if in industrial condition. Since the incubation divides the roll into two zones: C and E; (the first with columnar structure and the second with fully equiaxed structure some experiments dealing with solidification were made on semi-industrial scale.

  11. 现浇泡沫混凝土围护结构自保温体系在寒冷地区应用研究%Application of self-insulation system for cast-in-place foam concrete envelope structure in the cold region

    Institute of Scientific and Technical Information of China (English)

    丁来彬; 袁伟; 刘涛; 张善德

    2016-01-01

    In this paper, according to the design requirements, the dry density rating of cast-in-place foam con⁃crete is calculated and determined to meet the envelope structure thermal performance parameter limits in the cold region A, and conducts test verifies of cast-in-place wall in lab according to the standard of“Thermal insulation, Determination of steady-state thermal transmission properties, Calibrated and guard hot box”(GB/T13475). Final⁃ly, the engineering application practice is taken place in Hotan, Xinjiang, thermal performance of the practical engi⁃neering envelope structure is tested by heat flow meter method and infrared thermal imaging technology, and the re⁃sults are in line with the national standards.%根据设计要求,计算确定满足寒冷A区围护结构热工性能参数限值的现浇泡沫混凝土干密度等级,并在实验室根据《绝热稳态传热性质的测定标定和防护热箱法》(GB/T13475)标准进行现浇墙体检测验证。最终在新疆和田地区进行工程应用实践。通过热流计法及红外热成像技术对实际工程围护结构进行热工性能检测,其热工性能检测结果均符合国家标准要求。

  12. Structure and mechanical properties of vermicular cast iron in cylinder head casting

    Directory of Open Access Journals (Sweden)

    E. Guzik

    2009-01-01

    Full Text Available The paper discusses the problem of grain density and ferrite content in microstructure of vermicular graphite iron cast in bars of different section diameters and cylinder head casting. The experimental results regarding the section effect demonstrate that the nodule count, grain density and ferrite content are all function of the cast bar diameter in this particular case ranging from 0.6 to 8.0 cm and microstructure and mechanical properties in the cylinder head. The nodule count (or grain density has been reported to increase, while ferrite content was decreasing with decreasing casting diameter. The density number of the grains Nv has been related (by regression analysis to the undercooling degree

  13. Cast in place temperature 5 influence on fresh concrete made with limestone filler and blended cement

    Directory of Open Access Journals (Sweden)

    Soria, E. A.

    2003-12-01

    Full Text Available Properties of fresh concrete play a relevant role on placing and consolidation; and its design strength and durability depends on them. It is well known too that the concrete temperature during placing affects all its properties in different ways and extent. This paper presents the influence of placing temperature of concretes made with portland cement, limestone filer cement and blended cement, commercially available, on slump, slump loss, setting time and bleeding. The results show that generally when concrete temperature rises, the bleeding and slump fall down and the slump loss and setting time are accelerated. However, regardless of the strength class the type of cement affects the value of these variations

    Las propiedades de los hormigones en estado fresco desempeñan un papel fundamental durante las operaciones de colocación y compactación de los mismos y de ellas depende, en gran medida, que se alcance en el estado endurecido la resistencia y la durabilidad de diseño. Es sabido, además, que la temperatura que alcanza un hormigón durante dichas operaciones, afecta en mayor o menor grado a todas sus propiedades, de manera diferente. En el presente trabajo se analizó la influencia de la temperatura de colocación sobre el asentamiento, la pérdida del asentamiento en el tiempo, los tiempos de fraguado y la exudación, en hormigones elaborados con cemento portland normal, fillerizado y compuesto, de procedencia comercial. Los resultados han mostrado, en general, que con el aumento de la temperatura de colocación disminuyen la exudación y el asentamiento; mientras que la pérdida de asentamiento y los tiempos de fraguado se aceleran. Sin embargo, las magnitudes de dichas variaciones resultan a su vez muy influenciadas por el tipo de cemento utilizado, aun siendo de la misma clase resistente.

  14. Seismic performance analysis and design suggestion for frame buildings with cast-in-place staircases

    Science.gov (United States)

    Feng, Yuan; Wu, Xiaobin; Xiong, Yaoqing; Li, Congchun; Yang, Wen

    2013-06-01

    Many staircases in reinforced concrete (RC) frame structures suffered severe damage during the Wenchuan earthquake. Elastic analyses for 18 RC structure models with and without staircases are conducted and compared to study the influence of the staircase on the stiffness, displacements and internal forces of the structures. To capture the yielding development and damage mechanism of frame structures, elasto-plastic analysis is carried out for one of the 18 models. Based on the features observed in the analyses, a new type of staircase design i.e., isolating them from the master structure to eliminate the effect of K-type struts, is proposed and discussed. It is concluded that the proposed method of staircase isolation is effective and feasible for engineering design, and does not significantly increase the construction cost.

  15. Static and cyclic pullout behavior of cast-in-place headed and bonded anchors with large embedment depths in cracked concrete

    Energy Technology Data Exchange (ETDEWEB)

    Delhomme, F., E-mail: fabien.delhomme@insa-lyon.fr [University of Lyon, INSA-Lyon, LGCIE, F-69621 Villeurbanne (France); Roure, T.; Arrieta, B. [EDF SEPTEN Compagny, Civil Engineering, Villeurbanne (France); Limam, A. [University of Lyon, INSA-Lyon, LGCIE, F-69621 Villeurbanne (France)

    2015-06-15

    Highlights: • Optimizing the design and identifying margin of the headed fasteners used in French nuclear power plants. • Static and cyclic pullout tests on cast in place anchorage composed of an anchor plate welded to four headed or bonded rods. • Experimental data base on tests on anchor plates. • Anchor with large embedment depths in cracked concrete. • Edge effects. - Abstract: The equipment of French nuclear power plants is fixed on reinforced concrete structures with base plate with headed fasteners. EDF decided to carry out an experimental research program in partnership with LGCIE in order to optimize the design of the headed fasteners and identify margin. This article introduces the results of pullout tests on anchors with large embedment cast in place in a reinforced concrete block. The anchorage are composed of an anchor plate welded to four ribbed bars or headed smooth studs. The studied parameters are: the type of loading (static or cyclic), the edge distance, the state of cracking of the concrete block. The anchors with headed rods or ribbed bars have a steel rod failure mode in agreement with their initial design. However, an optimization of the size on the headed anchors seems to be expected in order to improve their installation. This experimental campaign will provide a data base enabling the development of numerical models in order to improve the design.

  16. Marketing: its place in organisational structure.

    Science.gov (United States)

    Bourne, H; Miles, C

    1993-06-01

    As a result of the reforms, provider units have to compete for contracts from HAs and GPFHs; the function of marketing has an outside focus in understanding, communicating with and providing for customers, and the internal role of ensuring services meet customers' needs. Humphrey Bourne and Christine Miles examine the marketing role in the NHS.

  17. The construction technology of cast-in-place hollow floor slab two casting instant-formation%现浇空心楼板二次浇筑一次成型施工技术

    Institute of Scientific and Technical Information of China (English)

    王志宏

    2012-01-01

    Combined with the subsidiary comprehensive building project of ICBC Shanxi branch,mainly described the features,technological process,construction method,quality control,safety measures of cast-in-place hollow floor slab,the floor slab structure of above ground fifteen floors used cast-in-place hollow beamless floor structure system,had good construction quality,gained the praise of construction units and related departments.%结合中国工商银行山西省分行附属综合楼工程,主要叙述了现浇空心楼板特点,工艺流程,施工方法,质量控制,安全措施,地上15层部分楼板结构采用现浇空心无梁楼盖结构体系,施工质量好,得到了建设单位和有关部门的好评。

  18. Design of reinforced concrete walls casted in place for the maximum normal stress of compression

    Directory of Open Access Journals (Sweden)

    T. C. Braguim

    Full Text Available It is important to evaluate which designing models are safe and appropriate to structural analysis of buildings constructed in Concrete Wall system. In this work it is evaluated, through comparison of maximum normal stress of compression, a simple numerical model, which represents the walls with frame elements, with another much more robust and refined, which represents the walls with shells elements. The designing of the normal stress of compression it is done for both cases, based on NBR 16055, to conclude if the wall thickness initially adopted, it is enough or not.

  19. Cast-in-place concrete walls: thermal comfort evaluation of one-storey housing in São Paulo State

    Directory of Open Access Journals (Sweden)

    H. M. Sacht

    Full Text Available This paper presents a proposal of thermal performance evaluation of a one-storey housing typology (TI24A executed by CDHU - Companhia de Desenvolvimento Habitacional e Urbano do Estado de São Paulo, considering the use of cast-in-place monolithic panels of concrete, with different thicknesses panels (8, 10 and 12 cm and density between 1600 and 2400 kg/m³. In this study, the specific purpose was discussing the influence of the characteristic of concrete walls on the housing thermal performance without slab. Was defined of first parameters of study (definition of the one-storey housing typology, survey about housing users behavior and cities choose and executed computational simulation (winter and summer, for four São Paulo State cities (São Paulo, São Carlos, Santos e Presidente Prudente, with the software Arquitrop 3.0 in a one-storey housing. Was observed that in winter and summer the typologies analyzed, the panels thickness variation had more influence about results than different concrete densities. The minimum level of thermal performance (M in winter has been granted for some cities, with exception of Santos. In summer one of São Paulo city’s typology was attended the minimum level of thermal performance in agreement with standard “NBR 15575 Residential buildings up to five storied - Performance, Part 1: General requirements”.

  20. [Casting faults and structural studies on bonded alloys comparing centrifugal castings and vacuum pressure castings].

    Science.gov (United States)

    Fuchs, P; Küfmann, W

    1978-07-01

    The casting processes in use today such as centrifugal casting and vacuum pressure casting were compared with one another. An effort was made to answer the question whether the occurrence of shrink cavities and the mean diameter of the grain of the alloy is dependent on the method of casting. 80 crowns were made by both processes from the baked alloys Degudent Universal, Degudent N and the trial alloy 4437 of the firm Degusa. Slice sections were examined for macro and micro-porosity and the structural appearance was evaluated by linear analysis. Statistical analysis showed that casting faults and casting structure is independent of the method used and their causes must be found in the conditions of casting and the composition of the alloy.

  1. Integrated Modeling of Process, Structures and Performance in Cast Parts

    DEFF Research Database (Denmark)

    Kotas, Petr

    the importance of a good gating system design. Hence, it is common to see, especially in gravity sand casting, “traditional gating systems” which are known for a straight tapered down runner a well base and 90º bends in the runner system. There are theories supported by experimental results claiming that flow...... patterns induced by non-optimal gating systems can cause a variety of defects which are generally not considered to be filling related, such as hot tears and channel segregates. By improving the gating technology in traditional gating systems it is possible to achieve much higher casting integrity.......g. chill design, riser design, gating system design, etc., which would satisfy these objectives the most. The first step in the numerical casting process simulation is to analyze mould filling where the emphasis is put on the gating system design. There are still a lot of foundry specialists who ignore...

  2. Structure and properties of gray iron casted in the electromagnetic field

    Directory of Open Access Journals (Sweden)

    J. Szajnar

    2009-07-01

    Full Text Available In the national [1] and foreign [2] literature the methods of improving the homogeneity of the structure of castings using forced convection of the solidifying metal in the casting mould or the crystallizer are presented. This article presents the influence of chosen parameters of the rotating electromagnetic filed that is forcing the movement of melted metal in the mould on the morphology of graphite and the abrasive wear of the grey cast iron. The effect of this examination is the obtained modification of the flake graphite divisions morphology and a alteration of the abrasive wear resistance of the castings manufactured this way.

  3. Discuss the Full Framing Construction of Cast-in-place Box Girder%浅谈现浇箱粱满堂支架搭设施工

    Institute of Scientific and Technical Information of China (English)

    黄亮

    2013-01-01

    在进行桥梁上部结构的箱梁现浇施工时,满堂支架法的应用已经非常普遍。但是在进行满堂支架法施工时,其施工事故发生的频率也比较高。如何有效提高满堂支架法的施工安全,是值得去深入探究的问题。%During conduct the box girder cast-in-place const-ruction of upper structure in bridge, the application of ful fra-ming method has become so common. But when making ful framing construction method, its construction has a high acide-nt frequency. It is worth to delve into the problem of how to i-mprove the method of ful framing construction safety.

  4. A Banding Structure in a Ni-Cu-Si Cast Alloy

    Institute of Scientific and Technical Information of China (English)

    Qi ZHENG; Yufeng ZHENG; Hongyu ZHANG; Xiaofeng SUN; Hengrong GUAN; Zhuangqi HU

    2008-01-01

    The solidified microstructure of a Ni-Cu-Si cast alloy has been investigated, and a kind of banding structure was observed. The results showed that, the banding structure was composed of coarser particles which were Ni3Si type of precipitates and similar to the fine particles precipitate uniformly distributed within matrix of Ni solid solution, in both crystal structure and composition. The formation of bandings was resulted from cast thermal stress and dislocation walls. It was found that the cracks propagated along these bandings in tensile test. The banding structure can be depressed by reducing the cast thermal stress, which can improve the Qtensile ductility.

  5. Structural causes of defects in a cast iron mill roll

    Directory of Open Access Journals (Sweden)

    J. Krawczyk

    2008-07-01

    Full Text Available This paper describes an analysis of a defective microstructure of a mill roll. For this purpose, a piece of a broken roll was collected. That roll was made of mottled cast iron. Its microstructure consisted of modular graphite, transformed ledeburite and a matrix composed of bainite and martensite. Metallographic investigations were performed nearby the fracture in the roll. Observations were conducted on polished sections, first not etched, and then etched, which allowed us to trace carefully the propagation of the fracture. There was found a strict correlation between the microstructure of the roll and the progress occurring in the crack. It was ascertained that the basic reason for the damage to the roll was banded precipitations of ledeburitic cementite. In addition, cementite formed a continuous network. Another microstructure defects of that roll are also precipitations of secondary carbides on the boundaries of former grain of austenite as well as the occurrence of upper bainite in its matrix. The results obtained hereunder allow broadening the data base relative to the genesis of damages to mill rolls, which in future will permit one to design a proper microstructure of cast iron mill rolls. Proper microstructure of cast iron mill roll should be shaped at the stage of designing the chemical composition, conditions of crystallization or heat treatment if any.

  6. Structure of ductile iron in thin walled castings

    Directory of Open Access Journals (Sweden)

    M. Górny

    2007-12-01

    Full Text Available It this work it has been shown that it is possible to produce thin wall ductile iron (TWDI castings with considerably length using Archimedes spiral with wall thickness of 1, 2 and 3 mm. Inmould technique was used to produce TWDI. It has been estimated castability and metallographic investigations were made using different moulding materials. From castability measurements result that it is possible to obtain thin wall ductile iron castings with wall thickness down to 1 mm with castability of 200 mm. Using mould with small ability to absorb heat castability increases twice. At wall thickness equal 3 mm castability reaches 1000 mm and using LDASC sand its value increases to over 1500 mm. Structure parameters for different wall thickness and moulding materials (graphite nodule count, ferrite and cementite fraction are plotted versus distance from the beginning of spiral. It is shown strong influence of LDASC sand (material with small ability to absorb heat on structure parameters (NF, Vf i VC revealing gradient character of TWDI.

  7. Influence of cast-in-place floor slab on damage style of frame structures under earthquake%现浇楼板对钢筋混凝土框架结构在地震作用下破坏形式的影响

    Institute of Scientific and Technical Information of China (English)

    阎红霞; 杨庆出; 李吉涛

    2011-01-01

    Many reinforced concrete (RC) frame structures were severely damaged or even collapsed during the May 12, 2008 great Wenchuan earthquake. Based on survey data collected in Dujiangyan, it was found that plastic hinges appeared at column end, instead of beam end, in many frame structures. This did not coincide with "strong column-weak beam" seismic design criterion. It was believed that one of the main reasons was insufficiently understanding the cast-in-place floor slab effect on frame structures. Applying finite element software ABAQUS, 3D elastic-plastic time history simulation of a "strong beam -weak column" RC frame structure in Dujiangyan was analyzed to probe the influence of cast-in-slab on frame seismic performance from structural view. Results showed that RC frame designed according to current codes usually can not achieve "strong column-weak beam" yield mechanism. The numerical results suggested that the rebar in the width of six times of the plate thickness may take part in calculating the bearing capacity of negative moment at the beam end; the model of a frame structure with floor slab is suitable for analyzing the elastic-plastic deflection of frame structures under rare big earthquakes.%“5.12”汶川地震造成一些钢筋混凝土框架结构损坏甚至倒塌.灾后调查发现,框架结构震害特点也一是柱端而非梁端出现塑性铰的“强梁弱柱”破坏形式,这与结构抗震设计概念中的“强柱弱梁”不符.国内外研究表明现浇楼板增大了梁端抗负弯承载力,但其对整个框架结构屈服机制的影响研究依然不足.针对这种现象,应用有限元软件ABAQUS对汶川地震中都江堰市某典型“强梁弱柱”框架进行三维动力弹塑性时程数值模拟,着重从结构角度上分析了现浇楼板对框架结构抗震性能的影响、探讨了负弯矩作用下梁端有效翼缘的取值.经分析,发现按照目前我国规范设计的框架在遭遇大震时较难实观“

  8. 钢筋混凝土现浇楼板裂缝原因分析与治理%On analysis of reasons for cracks on reinforced concrete cast-in-place floors and treatment

    Institute of Scientific and Technical Information of China (English)

    吕海亭

    2016-01-01

    结合工作经验,分析了钢筋混凝土现浇楼板裂缝发生的原因,从设计、材料、施工等方面,阐述了治理钢筋混凝土现浇楼板裂缝的对策,旨在提高现浇楼板的施工质量,保证建筑结构的安全性。%Combining with work experience,the paper analyzes the reasons for the cracks on reinforced concrete cast-in-place floors,and illus-trates the strategies for the treatment of the cracks on the floors from the design,materials,and construction,so as to improve the construction quality of the cast-in-place floors and ensure the safety of the architectural structure.

  9. Balance fatigue design of cast steel nodes in tubular steel structures.

    Science.gov (United States)

    Wang, Libin; Jin, Hui; Dong, Haiwei; Li, Jing

    2013-01-01

    Cast steel nodes are being increasingly popular in steel structure joint application as their advanced mechanical performances and flexible forms. This kind of joints improves the structural antifatigue capability observably and is expected to be widely used in the structures with fatigue loadings. Cast steel node joint consists of two parts: casting itself and the welds between the node and the steel member. The fatigue resistances of these two parts are very different; the experiment results showed very clearly that the fatigue behavior was governed by the welds in all tested configurations. This paper focuses on the balance fatigue design of these two parts in a cast steel node joint using fracture mechanics and FEM. The defects in castings are simulated by cracks conservatively. The final crack size is decided by the minimum of 90% of the wall thickness and the value deduced by fracture toughness. The allowable initial crack size could be obtained through the integral of Paris equation when the crack propagation life is considered equal to the weld fatigue life; therefore, the two parts in a cast steel node joint will have a balance fatigue life.

  10. Solidifei d Structure Si mulation of the Cylinder Sleeves Castings in Vertical Centrifugal Casting%汽缸套立式离心铸造工艺仿真

    Institute of Scientific and Technical Information of China (English)

    凌有临; 夏乐春; 唐文献; 张宗政; 时学生

    2014-01-01

    运用ProCAST数值模拟软件对汽缸套立式离心铸造过程进行了数值模拟,确定了汽缸套铸件数值模拟的相关工艺参数:浇注速度2kg/s、浇注温度1300℃、铸型转速5000r/min。对汽缸套的立式离心铸造过程进行数值模拟分析,可以有效地预测缺陷,提高铸件质量,为生产提供了依据。%Taking ProCAST software to simulate the cylinder sleeves in complicated vertical centrifugal casting process, it determines the parameters for microstructure simulation , analyzes the cylinder liners in vertical cen-trifugal casting process , obtains the parameters required for the simulation of solidification structure for the cylin-der sleeve castings .It presents the related process simulation parameters such as casting rate:2kg/s, casting temperature:1300℃and mould speed:5000 r/min.The simulation analysis for vertical centrifugal casting cyl-inder liners process can effectively predict defects , improve the quality of castings and provide the basis for the production .

  11. Model Test Research on the End Bearing Behavior of the Large-Diameter Cast-in-Place Concrete Pile for Jointed Rock Mass

    Directory of Open Access Journals (Sweden)

    Jingwei Cai

    2016-01-01

    Full Text Available For large-diameter, cast-in-place concrete piles, the end bearing capacity of a single pile is affected by discontinuous surfaces that exist in natural rock masses when the bearing layer of the pile end is located in the rock layer. In order to study the influence of the jointed dip angle on the bearing characteristics of the pile end, the discrete element models are adopted to simulate the mechanical characteristics of the jointed rock masses, and the model tests of the failure mode of the jointed rock masses were also designed. The results of the numerical calculations and modeling tests show that the joints, which have a filtering effect on the internal stress of the bedrock located at the pile end, change the load transferring paths. And the failure mode of the jointed rock foundation also changes as jointed dip angle changes. The rock located at the pile end generally presents a wedge failure mode. In addition, the Q-S curves obtained by model tests show that the ultimate end bearing capacity of a single pile is influenced by the jointed dip angle. The above results provide an important theoretical basis for how to correctly calculate end resistance for a cast-in-place concrete pile.

  12. On prevention of cast-in-place concrete floor cracks%现浇混凝土楼板裂缝的防治

    Institute of Scientific and Technical Information of China (English)

    吕学刚

    2009-01-01

    分析了现浇混凝土楼板裂缝产生的原因,探讨了楼板裂缝产生的危害,并提出了现浇楼板裂缝的控制措施和弥补处理措施,以有效遏制楼板裂缝,从而提高建筑物的工程质量.%The paper analyzes reasons for cracks on floor of east-in-place concrete, explores the damage of the cracks on the floor, and points out some control measures and repairing treatment of the cast-in-place concrete floor, so as to check the floor cracks effectivdy and to improve the project quality of building.

  13. Structure-property-processing correlations in freeze-cast composite scaffolds.

    Science.gov (United States)

    Hunger, Philipp M; Donius, Amalie E; Wegst, Ulrike G K

    2013-05-01

    Surprisingly few reports have been published, to date, on the structure-property-processing correlations observed in freeze-cast materials directionally solidified from polymer solutions, or ceramic or metal slurries. The studies that exist focus on properties of sintered ceramics, that is materials whose structure was altered by further processing. In this contribution, we report first results on correlations observed in alumina-chitosan-gelatin composites, which were chosen as a model system to test and compare the effect of particle size and processing parameters on their mechanical properties at a specific composition. Our study reveals that highly porous (>90%) hybrid materials can be manufactured by freeze casting, through the self-assembly of a polymer and a ceramic phase that occurs during directional solidification, without the need of additional processing steps such as sintering or infiltration. It further illustrates that the properties of freeze-cast hybrid materials can independently be tailored at two levels of their structural hierarchy, allowing for the simultaneous optimization of both mechanical and structural requirements. An increase in freezing rate resulted in decreases in lamellar spacing, cell wall thickness, pore aspect ratio and cross-sectional area, as well as increases in both Young's modulus and compressive yield strength. The mechanical properties of the composite scaffolds increased with an increasing particle size. The results show that both structure and mechanical properties of the freeze-cast composites can be custom-designed and that they are thus ideally suited for a large variety of applications that require high porosity at low or medium load-bearing capacity.

  14. Fracture Mechanisms in Steel Castings

    Directory of Open Access Journals (Sweden)

    Z. Stradomski

    2013-07-01

    Full Text Available The investigations were inspired with the problem of cracking of steel castings during the production process. A single mechanism of decohesion - the intergranular one - occurs in the case of hot cracking, while a variety of structural factors is decisive for hot cracking initiation, depending on chemical composition of the cast steel. The low-carbon and low-alloyed steel castings crack due to the presence of the type II sulphides, the cause of cracking of the high-carbon tool cast steels is the net of secondary cementite and/or ledeburite precipitated along the boundaries of solidified grains. Also the brittle phosphor and carbide eutectics precipitated in the final stage solidification are responsible for cracking of castings made of Hadfield steel. The examination of mechanical properties at 1050°C revealed low or very low strength of high-carbon cast steels.

  15. A method for the realization of complex concrete gridshell structures in pre-cast concrete

    DEFF Research Database (Denmark)

    Larsen, Niels Martin; Egholm Pedersen, Ole; Pigram, Dave

    2012-01-01

    This paper describes a method for the design and fabrication of complex funicular structures from discrete precast concrete elements. The research proposes that through the integration of digital form finding techniques, computational file-to-fabrication workflows and innovative sustainable...... concrete casting techniques, complex funicular structures can be constructed using prefabricated elements in a practical, affordable and materially efficient manner. A recent case study is examined, in which the methodology has been used to construct a pavilion. Custom written dynamic relaxation software...... in collaboration between the Aarhus School of Architecture and the University of Technology, Sydney (UTS). Basic research in casting techniques defined the framework for the design process, and a custom written dynamic relaxation software application became the primary form-generating tool in the design process...

  16. [The cast structure after vacuum-pressure casting and centrifugal casting].

    Science.gov (United States)

    Finger, W; Jung, T; Quast, U

    1975-02-01

    Evaluation of polished sections revealed the following: 1. Grain size in marginal areas of the crown is, in general, smaller than it is in the occlusal region. 2. Grain size varies depending on the casting method applied. Differences in hardness were found only to a limited extent. They were not always in line with the grain structure. This phenomenon deviating from the rule cannot satisfactorily be explained. The piping distribution was in accordance with observations made so far.

  17. Genetic structure of Rajaka caste and affinities with other caste populations of Andhra Pradesh, India.

    Science.gov (United States)

    Parvatheesam, C; Babu, B V; Babu, M C

    1997-01-01

    The present study gives an account of the genetic structure in terms of distribution of a few genetic markers, viz., A1A2B0, Rh(D), G6PD deficiency and haemoglobin among the Rajaka caste population of Andhra Pradesh, India. The genetic relationships of the Rajaka caste with other Andhra caste populations were investigated in terms of genetic distance, i.e., Sq B (mn) of Balakrishnan and Sanghvi. Relatively lesser distance was established between the Rajaka and two Panchama castes. Also, the pattern of genetic distance corroborates the hierarchical order of the Hindu varna system.

  18. Research progress on squeeze casting in China

    Institute of Scientific and Technical Information of China (English)

    Li Yuanyuan; Zhang Weiwen; Zhao Haidong; You Dongdong; Zhang Datong; Shao Ming; Zhang Wen

    2014-01-01

    Squeeze casting is a technology with short route, high efficiency and precise forming, possessing features of casting and plastic processing. It is widely used to produce high performance metallic structural parts. As energy conservation and environmental protection concerns have risen, lightweight and high performance metal parts are urgently needed, which accelerated the development of squeeze casting technology over the past two decades in China. In this paper, research progress on squeeze casting aloys, typical parts manufacturing and development of squeeze casting equipment in China are introduced. The future trend and development priorities of squeeze casting are discussed.

  19. 混凝土灌注桩裂缝处理应用技术研究%Research on the application technology of cracking treatment for concrete driven cast-in-place pile

    Institute of Scientific and Technical Information of China (English)

    郁孟龙

    2011-01-01

    介绍温州市城区防洪堤工程混凝土灌注桩裂缝产生经过.混凝土灌注桩为防洪堤基础结构,对出现裂缝的灌注桩进行全面的裂缝特性以及桩身完整性检测.裂缝处理采用注射法以低黏度、高强度的YZJ-5裂缝修补胶液进行修补,并在裂缝处用4层高强度的Ⅱ级碳纤维布进行包覆处理,外层再用4层玻璃纤维布包覆进行防护,能有效封闭裂缝、防止海水侵蚀钢筋,又能对桩身进行补强,取得了较好的工程处理效果.%The occurrence process of crack in concrete driven cast-in-situ pile in anti-flood dike engineering of Wenzhou City is introduced. The concrete driven cast-in-situ pile is the foundation structure of anti-flood dike,an overall check of crack characteristic and pile integrity to those driven cast-in-place piles with cracks are carried out. Crack-repairing glue with low viscosity and high strength is used to inject into cracks,on which 4 layers of grade Ⅱ carbon fibre and 4 layers of glass fibre are applied successively,with effective closure of cracks,preventing erosion from sea water into reinforcement,and strengthening of pile, better treatment results are obtained from above.

  20. Structure-Property-Processing Correlations in Freeze-Cast Hybrid Scaffolds

    Science.gov (United States)

    Hunger, Philipp Malte

    Porous materials are highly sought after for applications ranging from catalyst carriers to tissue scaffolds. Most applications require clearly defined structural features and a specific mechanical performance. Therefore, it is essential to establish systematic structure-property-processing correlations to be able to tailor both structure and mechanical properties for a particular application. Because the introduction of porosity is detrimental to the mechanical performance of highly porous structures, it is necessary to generate a structure that allows for the mechanical properties to be maximized. One example for such a structure are honeycombs. In addition to the porosity and pore morphology, the scaffold's performance depends on the properties inherent to the material from which it is made. Polymeric foams possess high toughness but low stiffness, whereas ceramic foams possess high stiffness but low toughness. Natural composites like bone, antler and nacre have both high stiffness and high toughness. This unusual set of mechanical properties is thought to be intricately linked to the multi-level hierarchical composite structure present in these materials. Great potential for the fabrication of stiff, strong and tough porous scaffolds is thus seen in nacre-like composite materials with a hierarchical, honeycomb-like structure. Freeze casting is a method with which such hybrid materials can be made, adding the third dimension to nacre by forming a highly porous, hierarchical bulk material, with dense, nacre-like cell walls. The nacre-like cell walls self-assemble during the directional freezing of a water-based ceramic-polymer slurry. Reported here are structure-property-processing correlations observed in these materials. They are unusual, because they are, like nacre, solely glued by a polymeric phase and not processed further by sintering. The results illustrate several pathways to control both structure and mechanical properties in freeze-cast composites and

  1. The Effect of Structural Quality on Fatigue Life in 319 Aluminum Alloy Castings

    Science.gov (United States)

    Özdeş, Hüseyin; Tiryakioğlu, Murat

    2016-12-01

    Tensile and fatigue life data for 319 aluminum alloy from seventeen datasets reported in four independent studies from the literature have been reanalyzed. Analysis of fatigue life data involved mean stress correction for different R ratios used in fatigue testing, inclusion of survival (runout) data along with failure data, as well as volumetric correction for Weibull distributions for different specimen sizes used in these studies. Tensile data have been transformed into the structural quality index, Q T, which is used as a measure of the structural quality of castings. A distinct relationship has been observed between the expected fatigue life and mean quality index. Moreover, fatigue strengths at 104 and 106 cycles have been found increase with quality index, providing further evidence about the relationship observed between structural quality and fatigue performance. Empirical equations between Basquin parameters and structural quality index have been developed. The use of the comprehensive methodology to estimate fatigue life is demonstrated with an example.

  2. The Effect of Structural Quality on Fatigue Life in 319 Aluminum Alloy Castings

    Science.gov (United States)

    Özdeş, Hüseyin; Tiryakioğlu, Murat

    2017-02-01

    Tensile and fatigue life data for 319 aluminum alloy from seventeen datasets reported in four independent studies from the literature have been reanalyzed. Analysis of fatigue life data involved mean stress correction for different R ratios used in fatigue testing, inclusion of survival (runout) data along with failure data, as well as volumetric correction for Weibull distributions for different specimen sizes used in these studies. Tensile data have been transformed into the structural quality index, Q T, which is used as a measure of the structural quality of castings. A distinct relationship has been observed between the expected fatigue life and mean quality index. Moreover, fatigue strengths at 104 and 106 cycles have been found increase with quality index, providing further evidence about the relationship observed between structural quality and fatigue performance. Empirical equations between Basquin parameters and structural quality index have been developed. The use of the comprehensive methodology to estimate fatigue life is demonstrated with an example.

  3. Analysis of the structure of castings made from chromium white cast iron resistant to abrasive wear

    Directory of Open Access Journals (Sweden)

    D. Kopyciński

    2009-10-01

    Full Text Available It has been proved that an addition of boron carbide and disintegrated steel scrap introduced as an inoculant to the chromium white cast iron changes the structure of castings. The said operation increases the number of crystallization nuclei for dendrites of the primary austenite. In this case, the iron particles act as substrates for the nucleation of primary austenite due to a similar crystallographic lattice. The more numerous are the dendrites of primary austenite and the structure more refined and the mechanical properties higher. Castings after B4C inoculation revealed a different structure of fine grained fracture. Primary precipitates of chromium carbide also appeared, reducing the mechanical properties of as-cast parts. Properly established heat treatment regime makes chromium iron castings regain their, originally high, mechanical properties.

  4. Cast Stainless Steel Ferrite and Grain Structure

    Energy Technology Data Exchange (ETDEWEB)

    Ruud, Clayton O.; Ramuhalli, Pradeep; Meyer, Ryan M.; Mathews, Royce; Diaz, Aaron A.; Anderson, Michael T.

    2012-09-01

    In-service inspection requirements dictate that piping welds in the primary pressure boundary of light-water reactors be subject to a volumetric examination based on the rules contained within the American Society of Mechanical Engineers Boiler and Pressure Vessel Code, Section XI. The purpose of the inspection is the reliable detection and accurate sizing of service-induced degradation and/or material flaws introduced during fabrication. The volumetric inspection is usually carried out using ultrasonic testing (UT) methods. However, the varied metallurgical macrostructures and microstructures of cast austenitic stainless steel piping and fittings, including statically cast stainless steel and centrifugally cast stainless steel (CCSS), introduce significant variations in the propagation and attenuation of ultrasonic energy. These variations complicate interpretation of the UT responses and may compromise the reliability of UT inspection. A review of the literature indicated that a correlation may exist between the microstructure and the delta ferrite content of the casting alloy. This paper discusses the results of a recent study where the goal was to determine if a correlation existed between measured and/or calculated ferrite content and grain structure in CCSS pipe.

  5. Caste in Itself, Caste and Class, or Caste in Class

    OpenAIRE

    Ramkrishna Mukherjee

    2015-01-01

    After the British conquered Bengal and eventually the whole of India,they set out to administer the colony. In this context they encountered two phenomena with which they were not familiar: (1) the relation of people to land for production (and not for revenue receiving, household living, etc.), and (2) the caste system of India, viz. the jati strati?cation of society.

  6. 现浇磷石膏墙体研究及性能试验分析%RESEARCH AND PERFORMANCE TEST ANALYSIS OF CAST-IN-PLACE PHOSPHOGYPSUM WALL

    Institute of Scientific and Technical Information of China (English)

    卢亚琴; 张华刚; 罗玚; 梁凡凡; 马克俭

    2014-01-01

    基于现浇磷石膏在住宅结构应用的研究现状及施工工艺,将磷石膏与磷渣粉、熟石灰和水泥混合成干物料,并掺入减水剂和缓凝剂加水搅拌,制作试件研究其抗压强度、放射性、凝结时间和含水率等基本性能。材料配合比9组,共制作27个立方体试件。抗压强度试验表明:现浇磷石膏墙体的抗压强度标准值在2.5~11.0 MPa之间,强度设计值可按0.478的标准值采用,完全可作框架填充墙及低层小开间住宅承重墙使用;另外,缓凝剂掺量对现浇磷石膏墙体抗压强度影响显著。基于推荐配合比的磷石膏试件的检测表明,现浇磷石膏墙体的初凝时间为45 min,终凝时间为55 min,能满足现场浇筑工艺要求;放射性检测结果符合国家标准对建筑主材放射性的要求;墙体5d的含水率为2.6%,基本能达到干燥状态。%It is described the research on cast-in-place phosphogypsum for residential structure and the summary of construction technology according to the engineering practice .Phosphogypsum , phosphorus slag power , slaked lime and cement are mixed into dry material , and then water reducing agent , retarder and water are added to stir , and 27 cube specimens considering 9 kinds of mixture ratio are made to test the compressive strength and radioactive and setting time and moisture content etc .The compressive strength tests show that the standard values of compressive strength of cast-in-place phosphogypsum wall are between 2.5~11.0 MPa, the strength design values can be 0.478 times of the standard values , and the phosphogypsum can be used for the filled walls of frame structure and the load -bearing walls of lower small bay residential houses .The volume of the retarder has an obvious effect on the compressive strength of cast-in-place phosphogypsum wall .The detection of the specimens show that the initial setting time and final setting time of cast-in-place

  7. EFFECT OF La-RICH RE ON THE STRUCTURE AND PROPERTIES OF B319 ALLOY IN LOST FOAM CASTING

    Institute of Scientific and Technical Information of China (English)

    吴国华; 谢敏; 王叶双; 马春江; 朱燕萍; 丁文江

    2002-01-01

    By use of ICP spectroscopy, energy spectrum analysis, hydrogen tester, image analyzer, the differential scanning calorimetric (DSC) and microscope analysis, the effects of RE on the Porosity, structure and properties of B319 aluminum alloy were studied. The results show that under the 0. 3 C/s slow cooling rate in lost foam casting, the effect of RE on modification and grain size of B319 aluminum alloy is little. With the increase of RE master alloy, the tensile strength and elongation increase. When RE>0. 15%, block-like La2Si2Al3 phase appear, and the tensile strength and elongation decrease. The results also show that the melt hydrogen content and casting porosity can be decreased greatly by adding 0.15% RE to aluminum melt. This is the important reason why RE improves the mechanical properties of casting under lost foam casting condition.

  8. On construction of cast-in-place concrete hollow plate of newly-built wards of some hospital%谈某医院新建病房现浇混凝土空心板的施工

    Institute of Scientific and Technical Information of China (English)

    宋白平

    2015-01-01

    The paper introduces the main construction craft of the cast-in-place concrete hollow plate of newly-built ward at some hospital,illus-trates the construction precautions and quality control measures in the pipeline allocation,thin-wall hollow plate positioning,and concrete grou-ting,and points out the cast-in-place concrete hollow plate is economical,environment-friendly and energy-saving.%介绍了某医院新建病房现浇混凝土空心板的主要施工工艺,阐述了管线布置、薄壁空心板定位、混凝土浇筑等施工注意事项及质量控制措施,指出现浇混凝土空心板具有经济、环保、节能等优势。

  9. Caste in Itself, Caste and Class, or Caste in Class

    Directory of Open Access Journals (Sweden)

    Ramkrishna Mukherjee

    2015-08-01

    Full Text Available After the British conquered Bengal and eventually the whole of India,they set out to administer the colony. In this context they encountered two phenomena with which they were not familiar: (1 the relation of people to land for production (and not for revenue receiving, household living, etc., and (2 the caste system of India, viz. the jati strati?cation of society.

  10. A Study the relationship between composition, structure and properties of ductile iron in continuous casting

    OpenAIRE

    2011-01-01

    The developed empirical relationships have practical significance and used for determine the structural composition of iron on known data of express-analysis and for optimization technical process of obtaining castings of ductile iron at Public corporation «Gomel foundry «TSENTROLIT».

  11. 3D structures of liquid-phase GaIn alloy embedded in PDMS with freeze casting.

    Science.gov (United States)

    Fassler, Andrew; Majidi, Carmel

    2013-11-21

    Liquid phase electronic circuits are created by freeze casting gallium-indium (GaIn) alloys, such as eutectic gallium-indium (EGaIn), and encapsulating these frozen components within an elastomer. These metal alloys are liquid at room temperature, and can be cast using either injection or a vacuum to fill a PDMS mold and placing the mold in a freezer. Once solidified, a GaIn alloy segment can be manipulated, altered, or bonded to other circuit elements. A stretchable circuit can be fabricated by placing frozen components onto an elastomer substrate, which can be either patterned or flat, and sealing with an additional layer of elastomer. Circuits produced in this fashion are soft, stretchable, and can have complex 3D channel geometries. In contrast, current fabrication techniques, including needle injection, mask deposition, and microcontact printing, are limited to 2D planar designs. Additionally, freeze casting fabrication can create closed loops, multi-terminal circuits with branching features, and large area geometries.

  12. Stability of Spatial Structure of Urban Agglomeration in China Based on Central Place Theory

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    This paper brings forward the concept of stability of the spatial structure of urban agglomeration (UA) based on Central Place Theory by introducing centrality index and fractal theory. Before assessment, K=4 is selected as parameter to calculate centrality index and fractal dimension (K represents the quantitive relationship between city and the counties in Central Place Theory), and then found the number of nodes, the type of spatial structure, the spatial allocation of nodes with different hierarchy affecting the stability of spatial structure. According to spatial contact direction and the level of stability, UAs in China are classified into five types. Finally, it is posed as a further question that how to use hierarchical relation K=6 and K=7 in central place system to coordinate with the assessment of stability of spatial structure is brought forward.

  13. Bainite obtaining in cast iron with carbides castings

    Directory of Open Access Journals (Sweden)

    S. Pietrowski

    2010-01-01

    Full Text Available In these paper the possibility of upper and lower bainite obtaining in cast iron with carbides castings are presented. Conditions, when in cast iron with carbides castings during continuous free air cooling austenite transformation to upper bainite or its mixture with lower bainte proceeds, have been given. A mechanism of this transformation has been given, Si, Ni, Mn and Mo distribution in the eutectic cell has been tested and hardness of tested castings has been determined.

  14. 现浇钢筋混凝土楼板裂缝处理分析%The Cast-in-place Reinforced Concrete Floor Crack Analysis

    Institute of Scientific and Technical Information of China (English)

    林海滨

    2013-01-01

    This paper combined with the specific engineering examples, analyzes the reasons caused the cracks on cast-in-p-lace reinforced concrete floor search, and puts forward the me-thod of crack treatment, which to offer a reference for similar engineering treatment.%文章结合具体工程实例,对现浇钢筋混凝土楼板裂缝产生原因的查找进行了分析,并提出了裂缝处理方法,可为类似工程处理提供参考。

  15. 现浇混凝土楼板裂缝的质量控制%On quality control 0f construction crack in cast-in-place concrete floor

    Institute of Scientific and Technical Information of China (English)

    汪志勇

    2011-01-01

    Cracks occurred on the floor through the understanding and analysis of the site,as well as to introduce cracks in the floor structure of the impact of construction for cast-in-place concrete floor construction of the causes of cracks are analyzed,from the%本文通过对楼板裂缝发生部位分析以及楼板裂缝对建筑结构造成的影响入手,针对现浇混凝土楼板施工裂缝产生的原因进行了分析,从优化混凝土配合比、改善养护工艺、规范施工操作规程、控制温度梯度变化等方面探讨了裂缝控制措施,最后介绍了裂缝的处理方法,以解决好裂缝问题,提高工程质量。

  16. The temperature gradient on section of casting in process of primary crystallization of chromium cast iron

    Directory of Open Access Journals (Sweden)

    A. Studnicki

    2008-08-01

    Full Text Available The methodology of defining in article was introduced the temperature gradient in process of primary crystallization during cooling the casting from chromium cast iron on basis of measurements of thermal field in test DTA-K3. Insert also the preliminary results of investigations of influence temperature gradient on structure of studied wear resistance chromium cast iron.

  17. The temperature gradient on section of casting in process of primary crystallization of chromium cast iron

    OpenAIRE

    2008-01-01

    The methodology of defining in article was introduced the temperature gradient in process of primary crystallization during cooling the casting from chromium cast iron on basis of measurements of thermal field in test DTA-K3. Insert also the preliminary results of investigations of influence temperature gradient on structure of studied wear resistance chromium cast iron.

  18. Structure and properties of stir-cast zinc alloys

    Energy Technology Data Exchange (ETDEWEB)

    LeHuy, H.; Blain J.; Masounave, J.; Bata, G.L. (Industrial Materials Research Institute, Boucherville, P.Q. (Canada))

    Stir casting (or rheocasting) of ZA-27 zinc alloys was investigated experimentally. By vigorously agitating the alloys during cooling, the dendrites that were forming were fragmented giving a unique structure composed of spherical and rosette shaped particles suspended in the remaining liquid. Under high shear rates ({center dot}{gamma} = 300s{sup {minus}1} or more) the slurries with primary particle concentrations as high as 60% displayed viscosities as low as 20 poises and could easily be casted. The effects of processing variables such as shearing and cooling rates and casting temperatures were studied. Their relative importance on the rheological and microstructural behavior of the stir cast alloys are discussed. Results from viscosity measurements on slurries show that non-dendritical ZA-27 alloys obey a power law fluid model. Finally, results from mechanical and compressive studies carried out on solidified slurries are discussed and compared to conventional casted and wrought alloy properties.

  19. Solidification and casting

    CERN Document Server

    Cantor, Brian

    2002-01-01

    INDUSTRIAL PERSPECTIVEDirect chillcasting of aluminium alloysContinuous casting of aluminium alloysContinuous casting of steelsCastings in the automotive industryCast aluminium-silicon piston alloysMODELLING AND SIMULATIONModelling direct chill castingMold filling simulation of die castingThe ten casting rulesGrain selection in single crystal superalloy castingsDefects in aluminium shape castingPattern formation during solidificationPeritectic solidificationSTRUCTURE AND DEFECTSHetergeneous nucleation in aluminium alloysCo

  20. Design and Analysis of Cast-in-place Concrete Hollow Floor%现浇混凝土空心楼盖的设计与分析

    Institute of Scientific and Technical Information of China (English)

    卢宇航

    2014-01-01

    经济的不断发展,使得我国的建筑行业得到了更好的发展。本文通过工程实例,分析比较了采用现浇混凝土空心楼盖和实心楼盖的工程量和造价,阐述了空心楼盖特点及优势,并对空心楼盖的设计要点进行了分析。%The unceasing development of economy, makes our country's construction industry has a bet er development. This paper through the engineering examples, analyzes the project volume and cost of cast-in-situ concrete hol ow floor and solid floor, expounds the characteristics and advantages of hol ow floor, and analyzes the key design points of hol ow floor.

  1. Effect of electromagnetic stirring on solidification structure of austenitic stainless steel in horizontal continuous casting

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    An investigation on the influence of low frequency rotary electromagnetic stirring on solidification structure of austenitic stainless steel in horizontal continuous casting was experimentally conducted and carried out on an industrial trial basis. The results show that application of appropriate electromagnetic stirring parameters can obviously improve the macrostructure of austenitic stainless steel, in which both columnar and equiaxed grains can be greatly refined and shrinkage porosity or cavity zone along centerline can be remarkably decreased due to eliminating intracrystalline and enlarging equiaxed grains zone. The industrial trials verify that the electromagnetic stirring intensity of austenitic stainless steel should be higher than that of plain carbon steel. Electromagnetic stirring has somewhat affected the macrostructure of austenitic stainless steel even if the magnetic flux density of the electromagnetic stirring reaches 90 mT (amplitude reaches 141 mT ) in average at frequency f=3-4Hz, which provides a reference for the optimization of design and process parameters when applying the rotary electromagnetic stirrer

  2. Effect of electromagnetic stirring on solidification structure of austenitic stainless steel in horizontal continuous casting

    Directory of Open Access Journals (Sweden)

    ZHOU Shu-cai

    2007-08-01

    Full Text Available An investigation on the influence of low frequency rotary electromagnetic stirring on solidification structure of austenitic stainless steel in horizontal continuous casting was experimentally conducted and carried out on an industrial trial basis. The results show that application of appropriate electromagnetic stirring parameters can obviously improve the macrostructure of austenitic stainless steel, in which both columnar and equiaxed grains can be greatly refined and shrinkage porosity or cavity zone along centerline can be remarkably decreased due to eliminating intracrystalline and enlarging equiaxed grains zone. The industrial trials verify that the electromagnetic stirring intensity of austenitic stainless steel should be higher than that of plain carbon steel. Electromagnetic stirring has somewhat affected the macrostructure of austenitic stainless steel even if the magnetic flux density of the electromagnetic stirring reaches 90 mT (amplitude reaches 141 mT in average at frequency f=3-4Hz, which provides a reference for the optimization of design and process parameters when applying the rotary electromagnetic stirrer.

  3. Strip Casting of High Performance Structural Alloys

    Institute of Scientific and Technical Information of China (English)

    S S Park; J G Lee; Nack J Kim

    2004-01-01

    There exists a great need for the development of high performance alloys due to increasing demands for energy conservation and environmental protection. Application of strip casting shows a strong potential for the improvement of properties of existing alloys and also for the development of novel alloy systems with superior properties. The present paper reviews our Center's activities in the development of high performance alloys by strip casting. Examples include (1) Al alloys, (2) wrought Mg alloys, and (3) bulk metallic glass (BMG) alloys.

  4. 论泵送混凝土现浇板裂缝产生机理及预防措施%Study on the mechanism caused the cracks in cast-in-place floor of pump concrete and preventive measures

    Institute of Scientific and Technical Information of China (English)

    许洪祥

    2009-01-01

    针对泵送混凝土现浇板产生的各种裂缝,从混凝土组成、搅拌、运输、泵送、浇筑、养护、支模等方面出发,通过对各生产环节的观察和试验,对裂缝产生的机理进行了深入、全面地分析,并针对不同问题提出了相应的预防措施,以减少或避免出现混凝土裂缝.%According to various cracks produced in cast-in-place floor of pump concrete, from the composition, mixing, transportation, pumping, pouring, curing and other aspects the mechanism caused the production of those cracks in cast-in-place floor of pump concrete are comprehensively analyzed based upon observation and experiments, at the same time corresponding preventive measures are proposed, in order to reduce and eliminate the production of those cracks in pump concrete.

  5. Graphite Formation in Cast Iron

    Science.gov (United States)

    Stefanescu, D. M.

    1985-01-01

    In the first phase of the project it was proven that by changing the ratio between the thermal gradient and the growth rate for commercial cast iron samples solidifying in a Bridgman type furnace, it is possible to produce all types of graphite structures, from flake to spheroidal, and all types of matrices, from ferritic to white at a certain given level of cerium. KC-135 flight experiments have shown that in a low-gravity environment, no flotation occurs even in spheroidal graphite cast irons with carbon equivalent as high as 5%, while extensive graphite flotation occurred in both flake and spheroidal graphite cast irons, in high carbon samples solidified in a high gravity environment. This opens the way for production of iron-carbon composite materials, with high carbon content (e.g., 10%) in a low gravity environment. By using KC-135 flights, the influence of some basic elements on the solidification of cast iron will be studied. The mechanism of flake to spheroidal graphite transition will be studied, by using quenching experiments at both low and one gravity for different G/R ratios.

  6. 现浇轻质保温复合墙体施工技术%Construction of Cast-in-place Lightweight Thermal Insulation Composite Wall

    Institute of Scientific and Technical Information of China (English)

    黄旭腾; 杨庆泽

    2014-01-01

    Cast-in-situ lightweight composite insulation wall is erected with light steel keel and ce-ment pressure plate, pouring molding with the new lightweight rigid insulation materials. The new lightweight rigid insulation materials consist of a large amount of tailings, fly ash, boron mud and other in-dustrial waste as the main raw material for recycling. The wall technology with light steel keel in construc-tion industry, horizontal transfer and infiltration of the technical content are researched for determining the construction of cast-in-situ light composite insulation wall, enhancing technology of green environmental protection and energy saving, reducing waste emissions, solving environmental pollution, saving the land resources with good economic benefit and social benefit.%现浇轻质保温复合墙体是利用轻钢龙骨和水泥压力板支模后,现场浇入新型轻质刚性保温材料而制成的一次成型复合墙体,其中新型轻质刚性保温材料是以大量尾矿粉、粉煤灰、硼泥等工业废弃物作为主要原材料,通过可回收再利用,实现变废为宝。通过建筑行业轻钢龙骨墙体施工工艺,横向转移和渗透其技术内容,研究确定现浇轻质保温复合墙体的施工技术,推广应用绿色环保节能技术,减少废弃物排放,解决环境污染问题,节约土地资源,具有良好的经济效益和社会效益。

  7. Analysis and Prevention about the Causes of Cracks on the Reinforced Concrete Cast-in-Place Floor Slab%混凝土现浇楼板裂缝的分析与防控

    Institute of Scientific and Technical Information of China (English)

    王振平

    2015-01-01

    In high-rise residential buildings,reinforced concrete frame cast-in-place reinforced concrete floor slab was widely used. But it was found that cracks often appeared in use of cast-in-place floor slab, cracks had brought many adverse effects to the unit and the owners. Aiming at the phenomenon,this paper analyzed the crack causes and proposed prevention and control measures.%在高层住宅建筑中,钢筋混凝土框架及钢筋混凝土现浇楼板被广泛采用。但在使用中发现,现浇楼板常出现裂缝,裂缝的产生给使用单位和业主带来了诸多不利影响。针对该现象,分析现浇楼板裂缝成因,并提出防控措施。

  8. Effect of Structure Parameters on Power and Magnetic Field in Electromagnetic Soft-Contact Continuous Casting System

    Institute of Scientific and Technical Information of China (English)

    DENG An-yuan; WANG En-gang; HE Ji-cheng

    2008-01-01

    To design a power source system and mold for electromagnetic soft-contact continuous casting process and to theoretically estimate the heat losses from the charges and the system power, the effect of structure parameters on system power and magnetic flux density distribution was calculated using finite element method. The results show that as for electromagnetic soft-contact continuous casting system with partial-segment type mold, the power consumption is much more than that with a full-segment type mold; about 62% of electric power is dissipated in the mold, and the effective acting range of magnetic field is relatively narrow. Optimizing mold structure is a crucial measure of remarkably reducing mold power consumption and saving electric energy. Increasing slit number, width, and length can remarkably increase the magnetic flux density in the mold and can reduce the electric energy consumption. Among structure parameters, slit number and slit width are relatively more effective to reduce energy consumption. For a round billet electromagnetic continuous casting system with diameter of 178 mm, the reasonable slit number, width, and length are about 24-32, 0.5-1.0 mm, and 160 mm, respectively.

  9. On analysis of cracks of cast-in-place concrete buildings' floors and its prevention measures%现浇混凝土楼板裂缝的原因分析和防治措施

    Institute of Scientific and Technical Information of China (English)

    魏英歌

    2012-01-01

    According to the cracks on the cast-in-place concrete buildings floors the common phenomenon,the paper analyzes the factors,including the construction,the design and materials by combining with the many-year experience and lessons from the construction practice,locates the comprehensive reasons for the floor cracks,and points out some factual prevention measures,so as to improve the construction quality of the cast-in-place floors.%针对现浇楼板裂缝这一十分普遍的现象,本文结合多年来在施工实践中的经验和教训,重点分析以施工为主、兼顾设计和材料等几方面的因素,找出楼面裂缝的综合性原因,并提出一些具体防治措施,以提高现浇楼板施工质量。

  10. INVESTIGATION OF ROTARY SPEED INFLUENCE ON STRUCTURE AND CHARACTERISTICS OF ZINC ALLOY ZnAl4Cu3 AT SPIN CASTING IN SILICONE MOULDS

    Directory of Open Access Journals (Sweden)

    M. Bajchichak

    2010-01-01

    Full Text Available Influence of the mould rotary speed on the structure and characteristics of zinc alloy ZnAl4Cu3 at centrifugal casting in silicone moulds using technology TEKCAST is investigated. 

  11. 信息动态%Origin of delamination/adhesion in co-casting and the open structure

    Institute of Scientific and Technical Information of China (English)

    2011-01-01

    PEI and PSf polymer solutions were used for co-casting. Mechanisms for delamination/adhesion were investigated. It was found that the contribution of the coagulation values of membrane solutions is insignificant to the adhesion of two layers. Instead, membrane shrinkage appears to play a significant role because composite membranes were obtained by minimising their shrinkage difference at the thickness direction by the increase of the coagulant temperature. In addition, the PVP in PSf solution also improves the adhesion between PEI and PSf layer. The open structure formation mechanism of PSf membrane was ascribed to a solvent enriched environment caused by the presence of PEI coating layer, which was confirmed by addition of a large amount of solvent into water coagulant. Finally, the concave defects formation on PSf surface was proposed as the impact of the growth of finger-like macrovoids in PEI layer. The results provides a solid theoretical basis for the expanding the application of co-casting technique.

  12. The quality of the joint between alloy steel and unalloyed cast steel in bimetallic layered castings

    Directory of Open Access Journals (Sweden)

    T. Wróbel

    2012-01-01

    Full Text Available In paper is presented technology of bimetallic layered castings based on founding method of layer coating directly in cast process so-called method of mould cavity preparation. Prepared castings consist two fundamental parts i.e. bearing part and working part (layer. The bearing part of bimetallic layered casting is typical foundry material i.e. ferritic-pearlitic unalloyed cast steel, whereas working part (layer is plate of austenitic alloy steel sort X2CrNi 18-9. The ratio of thickness between bearing and working part is 8:1. The aim of paper was assessed the quality of the joint between bearing and working part in dependence of pouring temperature and carbon concentration in cast steel. The quality of the joint in bimetallic layered castings was evaluated on the basis of ultrasonic non-destructive testing, structure and microhardness researches.

  13. Risk Identification and Countermeasure for Construction of Cast-in Place Pile in Large Bridge%大型桥梁钻孔灌注桩施工风险识别与应对策略

    Institute of Scientific and Technical Information of China (English)

    李军; 张帆

    2011-01-01

    Combined with the construction characteristics of cast-in place pile in large bridge,the article discusses the importance of risk identification and also identify the risk factors existing through decomposition method.Corresponding countermeasures and meth-ods are proposed in the end.%文章结合大型桥梁钻孔灌注桩的施工特点,阐述了风险识别的重要性,并采用分解分析法对钻孔灌注桩施工过程中的风险因素进行分析识别,提出了相应的风险应对策略及措施。

  14. Influence of tungsten and titanium on the structure of chromium cast iron

    Directory of Open Access Journals (Sweden)

    D. Kopyciński

    2012-01-01

    Full Text Available The paper analyses the as-cast state structure of chromium cast iron designed for operation under harsh impact-abrasive conditions. In the process of chromium iron castings manufacture, very strong influence on the structure of this material have the parameters of the technological process. Among others, adding to the Fe-Cr-C alloy the alloying elements like tungsten and titanium leads to the formation of additional carbides in the structure of this cast iron, which may favourably affect the casting properties, including the resistance to abrasive wear.

  15. Changes of structure in nickel-based cast materials IN 100 and IN 713C after creep load

    Energy Technology Data Exchange (ETDEWEB)

    Pillhoefer, H.; Track, W.; Wege, R.

    1987-01-01

    Creep values of the nickel-based cast alloys IN 100 and IN 713C were determined at the Institute for Materials of the Darmstadt Technical College on behalf of the FVV Working Party on 'Long Term Creep' and these were evaluated with the aim of: Producing documentation of structural changes, documentation of changes of the ..gamma.. separation phase depending on temperature, stress and time. Clearing up the stress to which ..gamma.. separation particles remain stable; from this one can judge how sensible it is to produce a defined hardened structure in IN 100 by heat treatment. Formulating subjects and tasks for an FVV Research Project 'Creep equations'. (orig./IHOE).

  16. Social structure is where the hearth is: a "woman's place" in Beti society.

    Science.gov (United States)

    Houseman, M

    1988-01-01

    the matrimonial ties to the mother's husband's group or (in the absence of bridewealth) to her father's group. Alignment is founded on ritual food distribution and operates through co-affinal links between women. On the level of lineage organization a woman's place is determined by a succession of mother-in-law/daughter-in-law ties. The woman's place in Beti society is thus defined by both the static domestic structure and by the dynamic supra-domestic lineage syste.

  17. Evaluation of porosity in Al alloy die castings

    Directory of Open Access Journals (Sweden)

    M. Říhová

    2012-01-01

    Full Text Available Mechanical properties of an Al-alloy die casting depend significantly on its structural properties. Porosity in Al-alloy castings is one of the most frequent causes of waste castings. Gas pores are responsible for impaired mechanical-technological properties of cast materials. On the basis of a complex evaluation of experiments conducted on AlSi9Cu3 alloy samples taken from the upper engine block which was die- cast with and without local squeeze casting it can be said that castings manufactured without squeeze casting exhibit maximum porosity in the longitudinal section. The area without local squeeze casting exhibits a certain reduction in mechanical properties and porosity increased to as much as 5%. However, this still meets the norms set by SKODA AUTO a.s.

  18. Comparison of environmental impacts of building structures with in situ cast floors and with precast concrete floors

    Energy Technology Data Exchange (ETDEWEB)

    Lopez-Mesa, Belinda; Pitarch, Angel; Tomas, Ana; Gallego, Teresa [Department of Mechanical Engineering and Construction (ESTCE), Universitat Jaume I, Av. Sos Baynat s/n, Castellon 12071 (Spain)

    2009-04-15

    In this paper, the environmental impacts of two types of slab systems are studied. The first type, a concrete-based one-way spanning slab, is the most common solution in residential buildings in Spain. The second type, a hollow core slab floor, is increasingly becoming more used in buildings, but is not being broadly used in residential buildings as yet. The study is undertaken through the Life Cycle Analysis methodology, applying the EPS 2000 method. The assessment shows that the environmental impact of a building structure with precast concrete floors is 12.2% lower than that with in situ cast floors for the defined functional unit. (author)

  19. PLACE AND ROLE OF THE STRUCTURAL FUNDS IN THE LOCAL BUDGET REVENUES

    Directory of Open Access Journals (Sweden)

    CRISTINEL ICHIM

    2016-06-01

    Full Text Available In this study we aim to analyse the place and role manifested within local budgets of Romania by a new category of revenues available to local authorities namely those from the Structural and Cohesion Funds of the EU. At the beginning of our scientific approach we have outlined the scope of local government revenues highlighting that in the section development of local budgets are also set off funds from the European Union. The research continues with a characterization of the structural funds in which, on the one hand, we have emphasized their importance to the development of territorial administrative units in Romania and on the other hand we showed some difficulties arising in the process of absorption of European funds. The analysis of financial resources from the EU funds within the local budgets from Romania is the last part of the article and is based on the quantitative analysis of the budget indicator, "amounts of the EU in the payments made and pre-financing" from existing data in the Statistical Yearbook of Romania, and highlights the place occupied by such income within local public revenues. This analysis shows that local public authorities from Romania have made significant progress in terms of accessing European funds, their share in total revenues of local budgets increased during 2008-2014.

  20. U 型现浇配筋混凝土薄壁空心装饰柱施工技术%On construction technique of U-shaped cast-in-place reinforced concrete thin-wall hollow decoration columns

    Institute of Scientific and Technical Information of China (English)

    姚国荣

    2015-01-01

    The paper describes the craft features for the U-shaped cast-in-place reinforced concrete thin-wall hollow decoration columns,illus-trates the construction craft procedure and material requirements by combining with its construction craft principle,and researches the construc-tion quality,safety and environment protection control measures,so as to achieve better economic and social benefits.%描述了 U 型现浇配筋混凝土薄壁空心装饰柱施工的工艺特点,结合其施工工艺原理,阐述了施工工艺流程及材料要求,并对施工质量、安全、环保控制措施进行了研究,以取得良好的经济、社会效益。

  1. Effect of liquid volume on the evolution of solidified structure in horizontal centrifugal casting

    Science.gov (United States)

    Esaka, H.; Kataoka, Y.; Shinozuka, K.

    2015-06-01

    Horizontal centrifugal casting process is widely applied for long products. However, it often has macro-segregation problems, such as band segregation. In order to understand solidification process in this process, in-situ observation using transparent substances has been performed. Here, the effect of liquid volume in the mold was investigated. Succinonitrile-water alloy was introduced in the glass cell and filling ratio of organic alloy was varied from 70 to 100 vol. % and the rotation rate was set to be 250 rpm. Equiaxed grains formed in case of low filling ratio. On the other hand, no equiaxed grain formed when the filling ratio was 100 vol. %. Strong fluid flow may be induced by the fluctuation of free surface and this may form equiaxed grains. However, when the area of free surface decreased with increasing filling ratio, the influence of free surface diminished and fluid flow was stabilized. Therefore, well-developed columnar zone grew and no equiaxed grains formed.

  2. Segregation in cast products

    Indian Academy of Sciences (India)

    A Ghosh

    2001-02-01

    Microsegregation gets eliminated significantly if subsequent hot working and/or annealing are done on cast products. Macrosegregation however persists, causing problems in quality, and hence, has to be attended to. Microsegregation is a consequence of rejection of solutes by the solid into the interdendritic liquid. Scheil’s equation is mostly employed. However, other equations have been proposed, which take into account diffusion in solid phase and/or incomplete mixing in liquid. Macrosegregation results from movements of microsegregated regions over macroscopic distances due to motion of liquid and free crystals. Motion of impure interdendritic liquid causes regions of positive macrosegregation, whereas purer solid crystals yield negative macrosegregation. Flow of interdendritic liquid is primarily natural convection due to thermal and solutal buoyancy, and partly forced convection due to suction by shrinkage cavity formation etc. The present paper briefly deals with fundamentals of the above and contains some recent studies as well. Experimental investigations in molten alloys do not allow visualization of the complex flow pattern as well as other phenomena, such as dendrite-tip detachment. Experiments with room temperature analogues, and mathematical modelling have supplemented these efforts. However, the complexity of the phenomena demands simplifying assumptions. The agreement with experimental data is mostly qualitative. The paper also briefly discusses centreline macrosegregation during continuous casting of steel, methods to avoid it, and the, importance of early columnar-to-equiaxed transition (CET) as well as the fundamentals of CET.

  3. Education and Caste in India

    Science.gov (United States)

    Chauhan, Chandra Pal Singh

    2008-01-01

    This paper analyses the policy of reservation for lower castes in India. This policy is similar to that of affirmative action in the United States. The paper provides a brief overview of the caste system and discusses the types of groups that are eligible for reservation, based on data from government reports. The stance of this paper is that…

  4. Place in Transition

    DEFF Research Database (Denmark)

    Mikkelsen, Jacob Bjerre; Lange, Ida Sofie Gøtzsche

    to be decommissioned, in the context of the North Sea no less than 600 oil rig structures are to be decommissioned within the next 30 years (Schmidt 2004), creating potentially transformable 'drosscapes' (Berger 2006). These structures are weaved into an enclosed network, an 'Oil World', inaccessible and disconnected......The oil industry has created economic growth and technological advances during the last 150 years, with inherent consequences. By the oil peak in 2006 this development is turning into a decline in the industry (Birol 2011). This leaves a large amount of disused facilities and structures...... from the 'Everyday World'. Within mobilities studies, research has focused on different aspects and consequences of the post-oil society (see Dennis & Urry 2009, Urry 2013). This paper discusses the conception of place within the enclosed 'Oil World' with point of departure in relocation...

  5. THE IMPACT OF STRUCTURAL, PETROGRAPHIC AND CLIMATIC FACTORS ON THE SLOPE STABILITY IN THE OPEN CAST MINE OF GRADNA

    Directory of Open Access Journals (Sweden)

    Ivan Tomašić

    1992-12-01

    Full Text Available This paper presents an analysis of a complexity of interrelated structural, petrologic and climatic factors that considerably affect the instabilities in the open cast mine of Gradna, near Samobor. The instabilities provoke the slope failures such as slides and slumps of rock material. During the protracted periodical investigations, the relationship among the factors of regional geology, tectonics, structural geology, petrography, engineering geology, rock mechanics and the rock mining technology was observed in the area. The local control of hydrogeologic properties, as well as climatic fluctuations of temperature and precipitation on the slope stability, was also recognized. It turned out that the structural relationships, characteristic of the manifold cataclased dolomite, stimulated the development of local instabilities, particularly during the period of low temperatures affecting the process of ground-water accumulation. When the temperatures are worm, the ground-water circulation is slow, exerting only the small-scale influence on the local instabilities (the paper is published in Croatian.

  6. Lost Foam Casting in China

    Institute of Scientific and Technical Information of China (English)

    YE Sheng-ping; WU Zhi-chao

    2006-01-01

    @@ 1. Lost Foam Casting Committee of Foundry Institution of Chinese Mechanical Engineering Society (FICMES) From the beginning of the 1990s, China entered a research and expansion climax in lost foam casting technology realm after the United States, Germany, and Japan etc.

  7. Place Branding in Systems of Place

    DEFF Research Database (Denmark)

    2015-01-01

    – like a city, region or nation brand – is per definition attached to a system of geographical abstractions in quasi-cartographic form in which each city, region or nation is understood in relation and contrast to other geographical entities. For those who seek to alter perceptions about a place......The pervasive managerial logic of branding has established a stable foothold in the context of place management. Yet the question of whether places, such as cities, regions and nations, can be effectively managed using marketing techniques remains elusive, as place brands and company brands have...... been observed to differ in various ways. A key characteristic of this difference is the possibility of a company brand of being created from scratch and having its associations and characteristics carefully tailored to suit the needs of its authors. While the control of a company brand can easily...

  8. Moving to place: childhood cancer treatment decision making in single-parent and repartnered family structures.

    Science.gov (United States)

    Kelly, Katherine Patterson; Ganong, Lawrence

    2011-03-01

    Few researchers have studied how parents from diverse family structures cope with childhood chronic illness. We designed this study to discern the childhood cancer treatment decision-making (TDM) process in these families. Using grounded theory, we interviewed 15 custodial parents, nonresidential parents, and stepparents who had previously made a major treatment decision for their children with cancer. "Moving to place" was the central psychosocial process by which parents negotiated involvement in TDM. Parents moved toward or were moved away from involvement based on parent position in the family (custodial, nonresidential, and stepparent), prediagnosis family dynamics, and time since diagnosis. Parents used the actions of stepping up, stepping back, being pushed, and stepping away to respond to the need for TDM. Parents faced additional stressors because of their family situations, which affected the TDM process. Findings from this study provide important insight into diverse families and their unique parental TDM experiences.

  9. Changes in Structural Characteristics of Hypoeutectic Al-Si Cast Alloy after Age Hardening

    Directory of Open Access Journals (Sweden)

    Lenka HURTALOVÁ

    2012-09-01

    Full Text Available The contribution describes influence of the age-hardening consist of solution treatment at 515 °C with holding time 4 hours, water quenching at 40 °C and artificial aging at different temperature 150 °C, 170 °C and 190 °C with different holding time 2, 4, 8, 16 and 32 hours on mechanical properties (tensile strength and Brinell hardness and changes in morphology of eutectic Si, Fe-rich and Cu-rich intermetallic phases in secondary (recycled AlSi9Cu3 cast alloy. A combination of different analytical techniques (light microscopy upon black-white and colour etching, scanning electron microscopy (SEM upon deep etching and energy dispersive X-ray analysis (EDX were therefore been used for the identification of the various phases. Quantitative study of changes in morphology of eutectic Si, Cu-rich and Fe-rich phases was carried out using Image Analyzer software NIS-Elements. Mechanical properties were measured in line with EN ISO. Age-hardening led to changes in microstructure include the spheroidization and coarsening of eutectic silicon, gradual disintegration, shortening and thinning of Fe- rich intermetallic phases, the dissolution of precipitates and the precipitation of finer hardening phase (Al2Cu further increase in the hardness and tensile strength in the alloy.DOI: http://dx.doi.org/10.5755/j01.ms.18.3.2430

  10. Where is 'place' in Aging in place?

    DEFF Research Database (Denmark)

    Blaakilde, Anne Leonora

    2015-01-01

    The aim of this article is to contribute a transnational perspective to the field of environmental gerontology and the concept of aging in place. Seniors from the northern hemisphere, among them Danish citizens, are increasingly adapting to transnational lives as they move to warmer climates...... in-home help. It is argued that we should consider public solutions to the problems faced by frail Danish citizens in transnational settings, enhancing their opportunities to live abroad....

  11. Rare Earth Additions in Continuously Cast Steel

    Science.gov (United States)

    Wilson, William G.; Heaslip, L. J.; Sommerville, I. D.

    1985-09-01

    Rare earth (lanthanide metals) addiiions to continuously cast steel are particularly advantageous because of their ability to refine as-cast structures, reduce segregation and increase hot ductility at temperatures just below that of solidification. The complete shape control of sulfides in steels containing Rare Earth Metals (REM), whether continuously cast or ingot cast, is primarily responsible for improvements in ductility related mechanical properties, weldability, fatigue resistance and resistance to hydrogen damage. Complete sulfide shape control can be obtained with REM additions at sulfur levels as high as.020%. The greatest improvements, however, are obtained with REM additions to low sulfur steels. However, to achieve full operational advantages afforded by REM, nozzle blockage problems must be circumvented. Water model studies indicate a possible solution.

  12. Effect of Injection Velocity on Structure Part Characteristic in AZ50 Die Casting Process with High Vacuum System

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    When diecasting large and thin Mg alloy parts, material defects occur, which include porosity, nonuniform mechanical properties, irregular surfaces, and incomplete filling. To resolve these problems, it is necessary to have uniform injection velocities and temperatures as well as control the melt. This study investigated the feasibility of producing large and thin components using a die caster by attaching a high vacuum system. In particular, the effects of injection velocity on surface quality and the mechanical properties of the products were investigated. Hence, an injection velocity scheme and a die structure capable of casting in a vacuum were proposed. As a result, it was found that the critical low injection velocity was 0.2 m/s to produce large thin Mg alloy structures having good mechanical properties.

  13. As-cast structure of DC casting 7075 aluminum alloy obtained under dual-frequency electromagnetic field

    Institute of Scientific and Technical Information of China (English)

    Zhi-hao Zhao; Zhen Xu; Gao-song Wang; Qing-feng Zhu; Jian-zhong Cui

    2014-01-01

    We have experimentally determined the as-cast structures of semi-continuous casting 7075 aluminum alloy obtained in the pres-ence of dual-frequency electromagnetic field. Results suggest that the use of dual-frequency electromagnetic field during the semi-continuous casting process of 7075 aluminum alloy ingots reduces the thickness of the surface segregation layer, increases the height of the melt menis-cus, enhances the surface quality of the ingot, and changes the surface morphology of the melt pool. Moreover, low-frequency electromag-netic field was found to show the most obvious influence on improving the as-cast structure because of its high permeability in conductors.

  14. The influence of the forced movement of components on the structure in fabricated AlSi/CrxCy composite castings

    Directory of Open Access Journals (Sweden)

    A. Dulęba

    2012-01-01

    Full Text Available Fabrication and microstructure of the AlSi11 matrix composite containing 10 % volume fraction of CrFe30C8 particles were presented in this paper. Composite suspension was manufactured by using mechanical stirring. During stirring process the temperature of liquid metal, time of mixing and rotational speed of mixer were fixed. After stirring process composite suspension was gravity cast into shell mould. The composites were cast, applying simultaneously an electromagnetic field. The aim of the present study was to determine the effect of changes in the frequency of the current power inductor on the morphology of the reinforcing phase in the aluminum matrix. The concept is based on the assumption that a chromium-iron matrix of CrFe30C8 particles dissolves and residual carbide phases will substantially strengthen the composite. The microstructure and interface structure of the AlSi11/CrFe30C8 composite has been studied by optical microscopy, scanning microscopy and X-ray diffraction.

  15. 铸造铝合金叶轮嵌铸铸铁轮芯结构设计及工艺要点%Structural Design and Process Essentials of Inlay Casting Iron Core in Cast Aluminum Impeller

    Institute of Scientific and Technical Information of China (English)

    洪美琴; 尹社新

    2011-01-01

    Inlay casting iron core sometimes looses in axial direction from the running cast aluminum impeller, then the fan will cause fault such as vibration and abnormal voice etc. The effects of the two different configurations of the cast aluminum iron core on the quality of the impeller were analyzed in this paper. Structural design of inlay core and casting technology of impeller were briefly explained.%采用嵌铸铸铁轮芯的铸造铝合金叶轮在运行中有时出现轴向松动的现象,使运转中的风机产生振动、异音等故障.文中对铸造铝合金叶轮中嵌铸铸铁轮芯的两种不同结构对叶轮质量的影响进行了分析,阐述了铸造铝合金叶轮中嵌铸铸铁轮芯的结构设计和工艺要点.

  16. Simulation of Heat Flow in Computational Method and Its Verification on the Structure and Property of Gray Cast Iron

    Directory of Open Access Journals (Sweden)

    S. K. Shaha

    2010-01-01

    Full Text Available Problem statement: The solidification of materials depends on the cooling rate of the materials which is governed by heat flow in the mould and alloy composition. Solidification rate also affects the structure and properties of the materials. Approach: In the present study, the heat flow of cold set resin bonded sand mould was simulated using JL Analyzer FEM analysis software. To verify the model, the gray cast iron was melted at 1350°C temperature and poured into a resin bonded sand mould at 1300°C. Results: It showed that most of the heat-reserve at the junction of the mould which was nearer to the source of liquid metal and the lowest heat-reserve at the end of the mould. So, the solidification rate was very high at the end of the mould wall whereas it was comparatively low near the sprue of the mould. Conclusion: Finally, depending on the heat-flow through the mould, the solidification rate changed the microstructure from chill, mottled and gray cast iron and hardness changed from 95.1 HRB-78.78 HRB.

  17. 三岔双向挤扩灌注桩在桥梁设计中的应用%Application of Cast-in-place Pile with Expanded Branches and Bells by 3-way Extruding Arms in Bridge Design

    Institute of Scientific and Technical Information of China (English)

    张睿

    2016-01-01

    Through the design analysis of a bridge project pile,the cast-in-place piles with expanded branches and bells by 3-way extruding arms in the basic principle and design method are described in this paper and their vertical bearing capacity are calculated.The economic advantage and vertical bear-ing capacity advantage are verified,and the problems of its application in bridge engineering design are presented.%通过对某桥梁项目灌注桩的设计分析,阐述了三岔双向挤扩灌注桩的基本原理和设计方法,分别计算了三岔双向挤扩灌注桩与普通钻孔灌注桩的单桩竖向承载力,验证了三岔双向挤扩灌注桩在经济性及桩基竖向承载力等方面的优势,并提出了该桩基在桥梁工程设计中需要注意的问题。

  18. Prediction of useful casting structure applying Cellular Automaton method

    Directory of Open Access Journals (Sweden)

    Z. Ignaszak

    2009-07-01

    Full Text Available The results of simulation investigations of primary casting’s structure made of hypoeutectic Al-Si alloy using the Calcosoft system with CAFE 3D (Cellular Automaton Finite Element module are presented. CAFE 3-D module let to predict the structure formation of complete castings indicating the spatial distribution of columnar and equiaxed grains. That simplified model concerns only hypoeutectic phase. Simulation investigations of structure concern the useful casting of camshaft which solidified in high-insulation mould with properly chills distribution. These conditions let to apply the expedient locally different simplified the grains blocs geometry which are called by the authors as pseudo-crystals. The mechanical properties in selected cross-sections of casing are estimated.

  19. 外加剂对脱硫石膏制备现浇墙体材料性能影响%Effect of Additive on Desulfurization Gypsum Cast-in-place Wall Material

    Institute of Scientific and Technical Information of China (English)

    武丽霞; 李冬; 任彦茹

    2015-01-01

    In order to broaden the usage of desulfurization gypsum, and fulfill the directly use of it, Monosodium glutamate was selected as retarder, poly carboxylic acid was selected as reducing agent, effects of which on desulfurization gypsum cast-in-place wall material were studied. Desul-furization gypsum was prebaked for 2 hours at 55℃, and then burned for 3 hours at 160℃, the standard consistency water demand was determined according to GB/T 17669.4-1999. The experi-ment results were as follows:with adding 3%Monosodium glutamate as retarder, 0.5%Poly carbo-xylic acid as reducing agent, and initial setting time of desulfurization gypsum cast-in-place wall material is about 54 min and final setting time extends to 96 min, which meet the requirements of construction. Dry flexural strength of the wall material is 3.31 MPa, dry compressive strength is 12.27 MPa.%为了拓宽我国脱硫石膏的利用途径,实现对脱硫石膏直接利用,本研究选取谷氨酸钠作为缓凝剂,聚羧酸作为减水剂,对脱硫石膏现浇墙体材料进行改性研究。试验结果表明:电厂的脱硫石膏经过55℃预烘干2 h,160℃烘干3 h,按照GB/T 17669.4-1999确定标稠需水量,添加3%谷氨酸钠作为缓凝剂,0.5%聚羧酸作为减水剂时,现浇墙体材料的初凝时间约54 min,终凝时间延长至96 min,复配后初终凝时间满足施工要求;墙体材料的绝干抗折强度为3.31 MPa,绝干抗压强度为12.27 MPa。

  20. Undercooling and nodule count in thin walled ductile iron castings

    DEFF Research Database (Denmark)

    Pedersen, Karl Martin; Tiedje, Niels Skat

    2007-01-01

    Casting experiments have been performed with eutectic and hypereutectic castings with plate thick¬nesses from 2 to 8 mm involving both temperature measurements during solidification and micro¬structural examination afterwards. The nodule count was the same for the eutectic and hypereutectic...... castings in the thin plates ( 4.3 mm) while in the 8 mm plate the nodule count was higher in the hypereutectic than in the eutectic castings. The minimum temperature prior to the eutectic recalescence (Tmin) was 15 to 20C lower for the eutectic than the hypereutectic castings. This is due to nucleation...... of graphite nodules which begins at a lover temperature in the eutectic than in the hypereutectic castings The recalescence (Trec) was however also larger for the eutectic casting and in the thin plates the maximum temperature after recalescence (Tmax) was the same in the eutectic and hypereutectic plates...

  1. 论现浇钢筋混凝土空心楼盖施工工艺%Construction Techniques of Hollow Cast-in-place Reinforced Concrete Floors

    Institute of Scientific and Technical Information of China (English)

    杨振山

    2012-01-01

    The project,the transformation of the underground garage in an urban village,covering 50,000 square meters,adopts the hollow cast-in-place reinforced concrete floor promoted by the Ministry of Construction as chief scientific and technological achievements for its floor and the national green material,high-strength light mandrel,which saves lots of concrete and reduces the weight of the floor with a cost reduction by 13 percent.%本工程为某城中村改造地下车库项目,建筑面积为5万m2,地下车库楼板采用建设部科技成果重点推广的现浇钢筋混凝土空心楼盖技术,采用国家推行的绿色建筑材料———高强度轻质芯模。为工程节省了大量的混凝土,减轻了楼板的重量,工程造价节约13%。

  2. Formation of microstructures in the spheroidal graphite cast iron

    Science.gov (United States)

    Wang, S.; Daloz, D.; Bruneseaux, F.; Lesoult, G.

    2012-01-01

    Pipeline systems for hydraulic networks are obtained via centrifugal casting of spheroidal graphite cast iron. The very high cooling rate that is achieved in the skin of the product can sometimes lead to carbide instead of graphite in cast iron. An experimental device has been built in the laboratory that allows reproducing the extreme thermal conditions encountered during formation of skin of centrifugally cast pipes. Liquid metal droplets fall on a cold substrate. Rapid directional solidification occurs. The temperature evolution of the lower surface of the droplet is recorded during the very first moment of the solidification (t cast state and the heat-treated state. They are compared to the centrifugally cast ones. A model of directional solidification of cast iron under a very large temperature gradient has been built. It allows explaining the transition from stable to metastable micro structure that was observed in the products and reproduced in the laboratory samples.

  3. THE RESULTS OF USING OF INDICATORS OF THE HIGH-TEST CAST IRON OF TYPE ICH STRUCTURE IN CONDITIONS OF PRODUCT

    Directory of Open Access Journals (Sweden)

    A. L. Majorov

    2006-01-01

    Full Text Available The results of development of the indicator of highstrength pig-iron are submitted in the report. The indicator using allows to carry out the testing of the pig-iron structure in conditions of manufacture without additional preparation of the casting surface.

  4. Discussion on improving cast-in-place concrete ribbed beam hollow floor with GBF honeycomb core construction technology%提高 GBF 蜂巢芯现浇混凝土密肋梁空心楼盖施工技术的探讨

    Institute of Scientific and Technical Information of China (English)

    张世明

    2015-01-01

    GBF蜂巢芯现浇混凝土密肋梁空心楼盖是一种新型的楼盖结构。本文从一个工程实例出发,介绍了蜂巢芯安装及相应的技术措施,详细介绍了提高其施工质量的模板、钢筋、混凝土技术措施。%Cast-in-place concrete ribbed beams hollow floor with GBF honeycomb core is a new type of floor structure.Based on an en-gineering example, this paper introduces the installation of honeycomb core and corresponding technical measures ,and the template, steel bar and concrete technical measures was introduced in detail to improve the quality of its construction.

  5. Structure and properties of polypropylene cast films: Polymer type and processing effects

    Science.gov (United States)

    Mileva, Daniela; Gahleitner, Markus; Gloger, Dietrich

    2016-05-01

    The influence of processing parameters in a cast film extrusion process of thin films of isotactic polypropylene homopolymer and random propylene-ethylene copolymer was analyzed. Variation of the chill roll temperature allowed changing the supercooling of the melt and thus the generation of different crystal polymorphs of iPP. Additional focus was placed on the effect of flow induced crystallization via changing the output rate of the line. The crystal structure and morphology of the materials were evaluated and correlated to selected optical and mechanical properties.

  6. Squeezing effect in the high-frequency vibratory penetration process of the cast-in-place pile sleeve%灌注桩套管高频振动贯入过程中挤土效应研究

    Institute of Scientific and Technical Information of China (English)

    肖勇杰; 陈福全; 林良庆

    2015-01-01

    With the development of the technique for constructing the cast-in-place piles with high frequency vibratory hammers, the cast-in-place piles have been widely used in construction engineering. The penetration mechanism of the pile sleeve driven by high frequency vibratory hammers remains unclear, and particularly the squeezing effect in the sleeve penetration has yet to be investigated. In this paper, a finite elements and infinite elements coupling model is developed for simulating the sleeve penetration process driven by high frequency vibratory hammers, and used to study the squeezing effects such as ground heaves, lateral soil displacement and excess pore pressure generation. The results indicate that the horizontal displacement induced by soil compaction increases with the increase of sleeve penetration depth, and for the vertical compaction displacement, the heave increases in shallow soil layers and the settlement increases in deep soil layers as the sleeve penetration depth increases. The maximum compaction displacement lags behind the sleeve penetration depth. The reason for heave in shallow soil layers is that the horizontal stress increment causes an increase in the vertical stress, and the depth of heave interface increases with the increase of dynamical load amplitude, while decreases with the increase of vibration frequency. The excess pore pressure increases with the increase of sleeve penetration depth, and exhibits an exponential attenuation trend as the radial distances increases.%随着全套管振动取土灌注桩施工工艺的发展,灌注桩在工程中的应用越来越广泛,但关于灌注桩套管高频振动贯入机制,特别是套管贯入引起的挤土效应研究还不全面。全面介绍了套管高频振动贯入全过程的有限元-无限元耦合模型的建立过程后,对地表隆起、土体侧移及超孔隙水压力等挤土效应的变化规律进行了详细研究。研究结果表明:水平向的挤土

  7. Comparison of marginal accuracy of castings fabricated by conventional casting technique and accelerated casting technique: An in vitro study

    Directory of Open Access Journals (Sweden)

    S Srikanth Reddy

    2013-01-01

    Full Text Available Background: Conventional casting technique is time consuming when compared to accelerated casting technique. In this study, marginal accuracy of castings fabricated using accelerated and conventional casting technique was compared. Materials and Methods: 20 wax patterns were fabricated and the marginal discrepancy between the die and patterns were measured using Optical stereomicroscope. Ten wax patterns were used for Conventional casting and the rest for Accelerated casting. A Nickel-Chromium alloy was used for the casting. The castings were measured for marginal discrepancies and compared. Results: Castings fabricated using Conventional casting technique showed less vertical marginal discrepancy than the castings fabricated by Accelerated casting technique. The values were statistically highly significant. Conclusion: Conventional casting technique produced better marginal accuracy when compared to Accelerated casting. The vertical marginal discrepancy produced by the Accelerated casting technique was well within the maximum clinical tolerance limits. Clinical Implication: Accelerated casting technique can be used to save lab time to fabricate clinical crowns with acceptable vertical marginal discrepancy.

  8. Synthesis and structural evaluation of freeze-cast porous alumina

    Energy Technology Data Exchange (ETDEWEB)

    Souza, Douglas F., E-mail: souzadf@outlook.com [Department of Metallurgical and Materials Engineering, Federal University of Minas Gerais — UFMG, Avenida Presidente Antônio Carlos, 6627, Campus UFMG, Belo Horizonte, MG CEP: 31270-901, Escola de Engenharia, bloco 2, sala 2230 (Brazil); Nunes, Eduardo H.M., E-mail: eduardohmn@gmail.com [Department of Metallurgical and Materials Engineering, Federal University of Minas Gerais — UFMG, Avenida Presidente Antônio Carlos, 6627, Campus UFMG, Belo Horizonte, MG CEP: 31270-901, Escola de Engenharia, bloco 2, sala 2230 (Brazil); Pimenta, Daiana S.; Vasconcelos, Daniela C.L. [Department of Metallurgical and Materials Engineering, Federal University of Minas Gerais — UFMG, Avenida Presidente Antônio Carlos, 6627, Campus UFMG, Belo Horizonte, MG CEP: 31270-901, Escola de Engenharia, bloco 2, sala 2230 (Brazil); Nascimento, Jailton F.; Grava, Wilson [Petrobras/CENPES, Avenida Horácio Macedo 950, Cidade Universitária, Ilha do Fundão, Rio de Janeiro, RJ CEP:21941-915 (Brazil); Houmard, Manuel [Department of Materials Engineering and Civil Construction, Federal University of Minas Gerais — UFMG, Avenida Presidente Antônio Carlos, 6627, Campus UFMG, Belo Horizonte, MG CEP: 31270-901, Escola de Engenharia, bloco 1, sala 3304 (Brazil); Vasconcelos, Wander L., E-mail: wlv@demet.ufmg.br [Department of Metallurgical and Materials Engineering, Federal University of Minas Gerais — UFMG, Avenida Presidente Antônio Carlos, 6627, Campus UFMG, Belo Horizonte, MG CEP: 31270-901, Escola de Engenharia, bloco 2, sala 2230 (Brazil)

    2014-10-15

    In this work we fabricated alumina samples by the freeze-casting technique using tert-butanol as the solvent. The prepared materials were examined by scanning electron microscopy and X-ray microtomography. Next, they were coated with sol–gel silica films by dip-coating. Permeability tests were carried out in order to assess the permeation behavior of the materials processed in this study. We observed that the sintering time and alumina loading showed a remarkable effect on both the structural properties and flexural strength of the freeze-cast samples. Nitrogen adsorption tests revealed that the silica prepared in this study exhibited a microporous structure. It was observed that the presence of silica coatings on the alumina surface decreased the CO{sub 2} permeance by about one order of magnitude. Because of the similar kinetic diameters of nitrogen and carbon dioxide, the CO{sub 2}/N{sub 2} system showed a separation efficiency that was lower than that observed for the He/CO{sub 2} and He/N{sub 2} systems. We noticed that increasing the feed pressure improved the separation capacity of the obtained materials. - Highlights: • Porous alumina samples obtained by the freeze-casting technique • Microporous silica coating prepared by a simple sol–gel dip-coating methodology • Samples examined by SEM, μ-CT, and nitrogen sorption tests • Mechanical tests were carried out in the freeze-cast samples. • The presence of silica coatings on the alumina surface decreased the CO{sub 2} permeance.

  9. Do attitudes toward societal structure predict beliefs about free will and achievement? Evidence from the Indian caste system.

    Science.gov (United States)

    Srinivasan, Mahesh; Dunham, Yarrow; Hicks, Catherine M; Barner, David

    2016-01-01

    Intuitive theories about the malleability of intellectual ability affect our motivation and achievement in life. But how are such theories shaped by the culture in which an individual is raised? We addressed this question by exploring how Indian children's and adults' attitudes toward the Hindu caste system--and its deterministic worldview--are related to differences in their intuitive theories. Strikingly, we found that, beginning at least in middle school and continuing into adulthood, individuals who placed more importance on caste were more likely to adopt deterministic intuitive theories. We also found a developmental change in the scope of this relationship, such that in children, caste attitudes were linked only to abstract beliefs about personal freedom, but that by adulthood, caste attitudes were also linked to beliefs about the potential achievement of members of different castes, personal intellectual ability, and personality attributes. These results are the first to directly relate the societal structure in which a person is raised to the specific intuitive theories they adopt.

  10. Solidification Structure of Low Carbon Steel Strips with Different Phosphorus Contents Produced by Strip Casting

    Institute of Scientific and Technical Information of China (English)

    Na LI; Zhenyu LIU; Yiqing QIU; Zhaosen LIN; Xianghua LIU; Guodong WANG

    2006-01-01

    In the present paper, low carbon steel strips with different phosphorus contents were produced using a twin roll strip casting process. The solidification structure was studied and its features were analyzed in detail. It was found that the strips possessed a fine microstructure compared with the mould cast steels. With increasing phosphorus content more ferrite has been formed with finer grains.

  11. Ageing in Communal Place

    DEFF Research Database (Denmark)

    Aarhus, Rikke; Ballegaard, Stinne Aaløkke; Grönvall, Erik;

    2009-01-01

    In this paper we adopt the position that design of social media for the elderly and virtual senior communities may be informed by studying ‘real’ senior communities. Since current research efforts target the role of social media and virtual communities for supporting seniors ageing in place, i...... these findings apply to designers of social media technologies. .......e. in their homes, housing communities seem a natural place to begin this enquiry. We conducted observations and informal interviews in six different senior dwellings. In this paper we present the key findings from these visits related to social interaction and the formation of communities and explicate how...

  12. Ageing in communal place

    DEFF Research Database (Denmark)

    Aarhus, Rikke; Ballegaard, Stinne Aaløkke; Grönvall, Erik;

    2009-01-01

    In this paper we adopt the position that design of social media for the elderly and virtual senior communities may be informed by studying `real´senior communities. Since current research efforts target the role of social media and virtual communities for supporting seniors ageing in place, i...... these findings apply to designers of social media technologies........e. in their homes, housing communities seems a natural place to begin this enquiry. We conducted observations and informal interviews in six different senior dwellings. In this paper we present the key findings from these visits related to social interaction and the formation of communities and explicate how...

  13. Displaying structural property and inheritance of cast iron surfacing on steel base

    Science.gov (United States)

    Shveev, I. A.

    2016-06-01

    Graphite inclusions heredity in deposited layer from remelted special cast iron billets was established. The possibility of controlling the structural state and the quality of the deposited layer due to technological parameters of welding and heat treatment of parts is shown. Ways of improving cast iron wear resistance durability are proposed.

  14. EXPERIMENTAL STUDIES ON ASEISMIC PERFORMANCE OF T-SHAPE FABRICATED CONCRETE JOINTS WITH PRECAST EXTERNAL SHELL AND CAST-IN-PLACE CORE CONCRETE%外壳预制核心现浇装配式T型钢筋混凝土节点抗震性能试验研究

    Institute of Scientific and Technical Information of China (English)

    张大长; 郭雁; 李布辉

    2013-01-01

    In order to investigate the aseismic performance of fabricated concrete T-shape exterior RC joint with precast external shells and cast-in-place core, one new-type assembled exterior joint and one parallel joint were fabricated, and cyclic loading tests of the T-shape joints were carried out. The aseismic performances were investigated, including failure modes, hysteretic property, ductility, energy dissipation, stiffness degradation. The studies showed that the new-type assembled T-joint had excellent integrity and aseismic performance, similar to those of the cast-in-place RC T-joint, and could meet the aseismic-design requirement of RC frame structure.%该文以研究外壳核心现浇预制装配式钢筋混凝土T型边节点的抗震性能为目的,制作一个新型装配式边节点和一个现浇边节点,开展两个T型节点抗震性能的低周反复试验,考察并分析比较采用两种不同施工方法的T型边节点的破坏形态、滞回特性、位移延性、能量耗散、刚度退化等抗震性能,研究表明新型装配式T型节点与RC现浇T型节点相似,具有良好的整体性和抗震性能,可以满足RC框架结构的抗震设计要求.

  15. Numerical Simulation System for Casting Process in Concurrent Engineering

    Institute of Scientific and Technical Information of China (English)

    1999-01-01

    According to the implementing principle and application background of the Concurrent Engineering (CE) project, studies on the integration of numerical simulation system for casting process with CE, simulation of turbulent phenomena in filling process of casting by Algebraic Stress Model (ASM), computation efficiency of filling process and quantitative prediction of shrinkage cavity and porosity under feeding condition of several risers are discussed. After the simulation of casting process of typical magnesium-based alloy casting with complicated structure, remarkable success in assuring the quality is also presented.

  16. Examples of material solutions in bimetallic layered castings

    Directory of Open Access Journals (Sweden)

    S. Tenerowicz

    2011-07-01

    Full Text Available In paper is presented technology of bimetallic layered castings based on founding method of layer coating directly in cast process so-called method of mould cavity preparation. Prepared castings consist two fundamental parts i.e. bearing part and working part (layer. The bearing part of bimetallic layered casting is typical foundry material i.e. pearlitic grey cast iron, whereas working part (layer is depending on accepted variant plates of alloy steels sort X6Cr13, X12Cr13, X10CrNi18-8 and X2CrNiMoN22-5-3. The ratio of thickness between bearing and working part is 8:1. The verification of the bimetallic layered castings was evaluated on the basis of ultrasonic NDT (non-destructive testing, structure and macro- and microhardness researches.

  17. Effect of Nb on Structure and Mechanical Properties of Chilled Cast Iron at Room and Elevated Temperatures

    Institute of Scientific and Technical Information of China (English)

    Qijie ZHAI; Li FU; Huaying ZHAI

    2004-01-01

    Effect of Nb on microstructure and mechanical properties of chilled cast iron at room and elevated temperatures is studied in this research. The results demonstrate that the cast structure and mechanical properties of chilled cast iron at room and elevated temperatures are improved with the addition of trace amount of Nb. However, if Nb was added too much, the cast structure and mechanical properties of chilled cast iron would deteriorate. The suitable content of Nb in chilled cast iron is about 0.05% (mass fraction). Except the dissolution in the matrix of cast iron the excessive Nb will form Nb-rich phases in three morphologies. Those are lumpy NbC, complicated strip-like phase and compound with pearlite structure.

  18. Construction Quality Control of Cast-in-place Concrete Hollow Floor with GBF Pipe%GBF管现浇混凝土空心楼板施工质量控制探讨

    Institute of Scientific and Technical Information of China (English)

    黄绍斌

    2014-01-01

    This paper according to the author's practices, co-mbined with an example of a GBF cast-in-situ hol ow floor engineering, with reference to the correlation datas, carries on the discussion to the cast-in-situ concrete hol ow floor with GBF pipe from the key point, technical construction measures, quality control, quality standards and so on.%本文主要根据笔者多年的工作实践,结合某 GBF现浇空心楼盖工程实例,并参考了相关资料,对现浇 GBF管混凝土空心楼板在技术关键点、构造措施、质量控制、质量标准等方面进行探讨。

  19. Structuring virtual spaces as television places

    DEFF Research Database (Denmark)

    Reinhard, CarrieLynn D.

    world.  Attaching such interactivity to their online distribution creates cyberspaces of consumption that become places for virtual audiences to congregate as they view the program.  To illustrate how the virtual environments and worlds are constructed to become places for virtual audiences, four case...... studies of virtual places are analyzed in terms of how interactivity is being managed.  Two types of interactivity are used to compare these case studies: social interaction and narrative interaction.  Broadcast networks CBS and NBC separately created virtual places to imitate “living room” conditions...... of social interaction.  Cable network SciFi Channel produced “live events” to allow limited narrative interaction.  Independent producer Metanomics created a virtual “talk show” to encourage both social interaction and narrative interaction.  The analysis is set into a larger theoretical framework...

  20. Prediction of Microporosity in Shrouded Impeller Castings

    Energy Technology Data Exchange (ETDEWEB)

    Viswanathan, S. Nelson, C.D.

    1998-09-01

    The purpose of this Cooperative Research and Development Agreement (CRADA) between the Oak Ridge National Laboratory (ORNL) and Morris Bean and Company was to link computer models of heat and fluid flow with previously developed quality criteria for the prediction of microporosity in a Al-4.5% Cu alloy shrouded impeller casting. The results may be used to analyze the casting process design for the commercial production of 206 o alloy shrouded impeller castings. Test impeller castings were poured in the laboratory for the purpose of obtaining thermal data and porosity distributions. Also, a simulation of the test impeller casting was conducted and the results validated with porosity measurements on the test castings. A comparison of the predicted and measured microporosity distributions indicated an excellent correlation between experiments and prediction. The results of the experimental and modeling studies undertaken in this project indicate that the quality criteria developed for the prediction of microporosity in Al-4.5% Cu alloy castings can accurately predict regions of elevated microporosity even in complex castings such as the shrouded impeller casting. Accordingly, it should be possible to use quality criteria for porosity prediction in conjunction with computer models of heat and fluid flow to optimize the casting process for the production of shrouded impeller castings. Since high levels of microporosity may be expected to result in poor fatigue properties, casting designs that are optimized for low levels of microporosity should exhibit superior fatigue life.

  1. Pressure distribution in centrifugal dental casting.

    Science.gov (United States)

    Nielsen, J P

    1978-02-01

    Equations are developed for liquid metal pressure in centrifugal dental casting, given the instantaneous rotational velocity, density, and certain dimensions of the casting machine and casting pattern. A "reference parabola" is introduced making the fluid pressure concept more understandable. A specially designed specimen demonstrates experimentally the reference parabola at freezing.

  2. Solidification Structure of Continuous Casting Large Round Billets under Mold Electromagnetic Stirring

    Institute of Scientific and Technical Information of China (English)

    Tao SUN; Feng YUE; Hua-jie WU; Chun GUO; Ying LI; Zhong-cun MA

    2016-01-01

    The solidification structure of a continuous casting large round billet was analyzed by a cellular-automaton-finite-element coupling model using the ProCAST software.The actual and simulated solidification structures were compared under mold electromagnetic stirring (MEMS)conditions (current of 300 A and frequency of 3 Hz).There-after,the solidification structures of the large round billet were investigated under different superheats,casting speeds,and secondary cooling intensities.Finally,the effect of the MEMS current on the solidification structures was obtained under fixed superheat,casting speed,secondary cooling intensity,and MEMS frequency.The model accurately simulated the actual solidification structures of any steel,regardless of its size and the parameters used in the continuous casting process.The ratio of the central equiaxed grain zone was found to increase with decreasing su-perheat,increasing casting speed,decreasing secondary cooling intensity,and increasing MEMS current.The grain size obviously decreased with decreasing superheat and increasing MEMS current but was less sensitive to the casting speed and secondary cooling intensity.

  3. Acoustic contributions of a sound absorbing blanket placed in a double panel structure: Absorption Versus Transmission

    CERN Document Server

    Doutres, Olivier; 10.1121/1.3458845

    2010-01-01

    The objective of this paper is to propose a simple tool to estimate the absorption vs. transmission loss contributions of a multilayered blanket unbounded in a double panel structure and thus guide its optimization. The normal incidence airborne sound transmission loss of the double panel structure, without structure-borne connections, is written in terms of three main contributions; (i) sound transmission loss of the panels, (ii) sound transmission loss of the blanket and (iii) sound absorption due to multiple reflections inside the cavity. The method is applied to four different blankets frequently used in automotive and aeronautic applications: a non-symmetric multilayer made of a screen in sandwich between two porous layers and three symmetric porous layers having different pore geometries. It is shown that the absorption behavior of the blanket controls the acoustic behavior of the treatment at low and medium frequencies and its transmission loss at high frequencies. Acoustic treatment having poor sound ...

  4. Casting behavior of titanium alloys in a centrifugal casting machine.

    Science.gov (United States)

    Watanabe, K; Miyakawa, O; Takada, Y; Okuno, O; Okabe, T

    2003-05-01

    Since dental casting requires replication of complex shapes with great accuracy, this study examined how well some commercial titanium alloys and experimental titanium-copper alloys filled a mold cavity. The metals examined were three types of commercial dental titanium [commercially pure titanium (hereinafter noted as CP-Ti), Ti-6Al-4V (T64) and Ti-6Al-7Nb (T67)], and experimental titanium-copper alloys [3%, 5% and 10% Cu (mass %)]. The volume percentage filling the cavity was evaluated in castings prepared in a very thin perforated sheet pattern and cast in a centrifugal casting machine. The flow behavior of the molten metal was also examined using a so-called "tracer element technique." The amounts of CP-Ti and all the Ti-Cu alloys filling the cavity were similar; less T64 and T67 filled the cavity. However, the Ti-Cu alloys failed to reach the end of the cavities due to a lower fluidity compared to the other metals. A mold prepared with specially designed perforated sheets was effective at differentiating the flow behavior of the metals tested. The present technique also revealed that the more viscous Ti-Cu alloys with a wide freezing range failed to sequentially flow to the end of the cavity.

  5. Signs in Place

    DEFF Research Database (Denmark)

    Hamid, Salmiah Binti Abdul; Jensen, Ole B.; Silva, Victor

    Travelling in unfamiliar areas is usually very interesting, however it can also be stressful. People travel or move around in an urban space according to their needs, and the environment can also influence the way people move about from one place to another. If a person gets lost, a map or GPS can...... and geosemiotic studies with regards to the road traffic signs used in urban spaces. The paper ends with a discussion on how people choreograph their movement in their everyday life from two different perspectives: above vs. below....

  6. Signs In Place

    DEFF Research Database (Denmark)

    Hamid, Salmiah Binti Abdul; Jensen, Ole B.; Silva, Victor

    2012-01-01

    Travelling in unfamiliar areas is usually very interesting; however, it can also be stressful. People travel or move around in an urban space according to their needs, and the environment can influence the way people move about from one place to another. If a person gets lost, a map or GPS can...... and geosemiotic studies with regards to the road traffic signs used in urban spaces. The paper ends with a discussion on how people choreograph their movement in their everyday life from two different perspectives: above vs. below...

  7. Context in place

    DEFF Research Database (Denmark)

    Nordentoft, Helle Merete; Thomsen, Rie

    The purpose of this paper is to provide a theoretical framework - i.e. a vocabulary - for understanding the importance of integrating context in analyses of guidance practices. The paper delineates a conceptual landscape of context based on social practice and interactional theories on context. We...... specifically argue for a more grounded approach to the conception of context - a topographic approach - in which the physical setting - i.e. 'the place' becomes an inevitable part of analyses of guidance practices in order to understand participants' sense-making processes. In the paper we draw on two case...

  8. Acoustic contributions of a sound absorbing blanket placed in a double panel structure: absorption versus transmission.

    Science.gov (United States)

    Doutres, Olivier; Atalla, Noureddine

    2010-08-01

    The objective of this paper is to propose a simple tool to estimate the absorption vs. transmission loss contributions of a multilayered blanket unbounded in a double panel structure and thus guide its optimization. The normal incidence airborne sound transmission loss of the double panel structure, without structure-borne connections, is written in terms of three main contributions; (i) sound transmission loss of the panels, (ii) sound transmission loss of the blanket and (iii) sound absorption due to multiple reflections inside the cavity. The method is applied to four different blankets frequently used in automotive and aeronautic applications: a non-symmetric multilayer made of a screen in sandwich between two porous layers and three symmetric porous layers having different pore geometries. It is shown that the absorption behavior of the blanket controls the acoustic behavior of the treatment at low and medium frequencies and its transmission loss at high frequencies. Acoustic treatment having poor sound absorption behavior can affect the performance of the double panel structure.

  9. Classification of Structure Defects of Metal Matrix Castings with Saturated Reinforcement

    Directory of Open Access Journals (Sweden)

    K. Gawdzińska

    2012-09-01

    Full Text Available Definition of a composite [1] describes an ideal composite material with perfect structure. In real composite materials, structure isusually imperfect – composites contain various types of defects [2, 3–5], especially as the casted composites are of concern. The reason for this is a specific structure of castings, related to course of the manufacturing process. In case of metal matrix composite castings, especially regarding these manufactured by saturation, there is no classification of these defects [2, 4]. Classification of defects in castings of classic materials (cast iron, cast steel, non-ferrous alloys is insufficient and requires completion of specific defects of mentioned materials. This problem (noted during manufacturing metal matrix composite castings with saturated reinforcement in Institute of Basic Technical Sciences of Maritime University Szczecin has become a reason of starting work aimed at creating such classification. As a result, this paper was prepared. It can contribute to improvement of quality of studied materials and, as a consequence, improve the environment protection level.

  10. Prediction of Part Distortion in Die Casting

    Energy Technology Data Exchange (ETDEWEB)

    R. Allen Miller

    2005-03-30

    The die casting process is one of the net shape manufacturing techniques and is widely used to produce high production castings with tight tolerances for many industries. An understanding of the stress distribution and the deformation pattern of parts produced by die casting will result in less deviation from the part design specification, a better die design and eventually more productivity and cost savings. This report presents methods that can be used to simulate the die casting process in order to predict the deformation and stresses in the produced part and assesses the degree to which distortion modeling is practical for die casting at the current time. A coupled thermal-mechanical finite elements model was used to simulate the die casting process. The simulation models the effect of thermal and mechanical interaction between the casting and the die. It also includes the temperature dependant material properties of the casting. Based on a designed experiment, a sensitivity analysis was conducted on the model to investigate the effect of key factors. These factors include the casting material model, material properties and thermal interaction between casting and dies. To verify the casting distortion predictions, it was compared against the measured dimensions of produced parts. The comparison included dimensions along and across the parting plane and the flatness of one surface.

  11. The mechanism of changes in the surface layer of grey cast iron automotive brake disc

    Directory of Open Access Journals (Sweden)

    Adam Polak

    2005-12-01

    Full Text Available The aim of the study was to create a model, describing the run of tribological processes in the surface layer of grey cast iron automotive brake discs. Grey cast iron discs mating with non-asbestos organic brake pads were chosen for the investigations, as the most widely used materials in car brakes. Samples for surface analysis were prepared from disc operating in stand and road conditions. Stand tests were pin-on-disc kind. Operating parameters for the stand tests were chosen on the basis of results of our earlier research. Topography of brake disc surface was evaluated by surface roughness measurements. The surface layer was examined with use of metallography and scanning electron microscopy. In order to differentiate structures of grey cast iron brake discs SE and BSE modes were used in scanning electron microscopy. Chemical investigations of samples were done by X-ray analysis linked with SEM. Studies showed influence of grey cast iron structures on tribological processes taking place in a brake friction pair. The surface layer of grey cast iron discs was described and features and functions of separated structures were presented. On the basis of the obtained results a physical model of friction mechanism was created. Special attention was paid to the influence of graphite on the run of tribological processes and mechanism of compaction and removal of wear debris.

  12. Strangers in Familiar Places

    DEFF Research Database (Denmark)

    Muhr, Sara Louise

    2012-01-01

    Employees working across multiple cultures are exposed to a vast number of different norms and values, and consequentially work is often a struggle to retain a coherent sense of self. However, when international workers travel, they also encounter more bland spaces where familiarity and similarity...... are important. These spaces appear culturally generic to the Western traveler, but are highly Westernized to bring comfort to Western employees traveling in foreign cultures. This paper argues that these spaces are important in cross-cultural identity work in the sense that international workers – professional...... strangers – need these places to belong and relate to familiarity and to regain a sense of identity. Drawing on an illustrative empirical vignette of an international consultant, I demonstrate how culturally generic spaces can be used in identity work of an international relations consultant....

  13. The place of human values in the language of science: Kuhn, Saussure, and structuralism.

    Science.gov (United States)

    Psaty, B M; Inui, T S

    1991-12-01

    The current paradigm in medicine generally distinguishes between genetic and environmental causes of disease. Although the word "paradigm" has become a commonplace, the theories of Thomas Kuhn have not received much attention in the journals of medicine. Kuhn's structuralist method differs radically from the daily activities of the scientific method itself. Using linguistic theory, this essay offers a structuralist reading of Thomas Kuhn's The Structure of Scientific Revolutions. Our purpose is to highlight the similarities between these structuralist models of science and language. In part, we focus on the logic that enables Kuhn to assert the priority of perception over interpretation in the history of science. To illustrate some of these issues, we refer to the distinction between environmental and genetic causes of disease. While the activity of scientific research results in the revision of concepts in science, the production of significant differences that shape our knowledge is in part a social and linguistic process.

  14. Discussion on the Design of Cast-in-situ Concrete Hollow Floor Structure%现浇混凝土空心楼盖结构设计探讨

    Institute of Scientific and Technical Information of China (English)

    2013-01-01

    In recent years, with the construction technology mature of cast-in-place concrete hol ow floor, this technique is widely used. This article explains the current development sit-uation of floor technology, makes an analysis of the force cha-racteristics of floor structure, expounds the calculation method of floor structure and scope, and briefly introduces the design points, structure and construction key of cast-in-situ concrete hol ow floor.%  近年来,随着现浇混凝土空心楼盖技术的成熟,建筑工程广泛地运用了这个技术。本篇文章详细解释了楼盖技术的发展现状,分析了楼盖结构的受力特性,重点阐述了楼盖结构的计算方法及适应范围,并对现浇混凝土空心楼盖结构的设计要点、构造及施工重点等进行简述。

  15. FEATURES OF STRUCTURE FORMATION AND CHANGES IN THE MECHANICAL PROPERTIES OF CAST Al-Mg-Si-Mn ALLOY WITH THE ADDITION OF (Ti+Zr

    Directory of Open Access Journals (Sweden)

    Oleksandr Trudonoshyn

    2015-08-01

    Full Text Available The as-cast and heat-treated structure of permanent mould castings of AlMg5Si2Mn alloys with different contents of Ti has been investigated by differential scanning calorimetry, hardness and microhardness measurements, tensile tests and fractography analyses, scanning electron microscopy, transmission electron microscopy, and energy dispersive X-ray analysis. We have established that α-Al dendrites can be nucleated on an Al-Ti substrate, and also that primary Mg2Si crystals can be nucleated on oxides, including oxides of Al and Ti compounds. The dependence of the change in mechanical properties on ageing time, and on the amount of Ti in the alloys, is shown.

  16. Prediction of the solidification structure of casting and heterogeneous nucleation

    Institute of Scientific and Technical Information of China (English)

    K. Ohsasa; H. Shirosawa; T. Narita

    2003-01-01

    The frequency of heterogeneous nucleation during the solidification of Al-Si binary alloy was estimated by comparing ex-perimentally obtained macrostructures of castings with numerically simulated ones. A molten alloy was unidirectionally solidifiedfrom a water-cooled copper chill in an adiabatic mold. The location of colunmar to equiaxed transition (CET) in the solidified alloyingot was measured. A numerical simulation for grain structure formation based on the Monte Carlo method was carried out, and thefrequency of heterogeneous nucleation in the alloy was evaluated by producing similar structure with the experimental one. The fre-quency of heterogeneous nucleation was expressed as a probabilistic function with an exponential form of undercooling that deter-mines the probability of nucleation event in the simulation. The value of the exponent is regarded as the nucleation parameter. Thenucleation parameter of Al-Si binary alloy varied with initial Sicontent.

  17. Thin wall ductile iron casting as a substitute for aluminum alloy casting in automotive industry

    Directory of Open Access Journals (Sweden)

    M. Górny

    2009-01-01

    Full Text Available In paper it is presented thin wall ductile iron casting (TWDI as a substitute of aluminium alloy casting. Upper control arm made of ductile iron with wall thickness ranging from 2 – 3.7 mm was produced by inmold process. Structure, mechanical properties and computer simulations were investigated. Structural analysis of TWDI shows pearlitic-ferritic matrix free from chills and porosity. Mechanical testing disclose superior ultimate tensile strength (Rm, yield strength (Rp0,2 and slightly lower elongation (E of TWDI in comparison with forged control arm made of aluminium alloy (6061-T6. Moreover results of computer simulation of static loading for tested control arms are presented. Analysis show that the light-weight ductile iron casting can be loaded to similar working conditions as the forged Al alloy without any potential failures.

  18. 现浇X形桩桩承式加筋路堤三维有限元分析%Three-dimensional finite element analysis of geogrid-reinforced embankment supported by X-section cast-in-place piles

    Institute of Scientific and Technical Information of China (English)

    陈力恺; 孔纲强; 刘汉龙; 金辉

    2013-01-01

    Geogrid-reinforced and pile-supported expressway embankment has been widely applied to soft ground improvement;but its bearing and deformation mechanism has not been deeply understood. Combining with the Fourth Yangtze River Bridge’s north-line soft ground reinforced project in Nanjing, the numerical method is used to analyze the variations of settlement and stress of pile and soil, pile axial force and excess pore water stress. The results show that road embankment load is mainly borne by piles as a result of the soil arching effect. The soil pressures of pile and soil increase with the development of embankment load firstly;and then the pressure of pile continue to increase while the pressure of soil decreases in the consolidation process of soft soil. The pile axial force increases quickly during the process of filling. Negative skin friction develops along most part of X-section cast-in-place pile shaft;and the neutral point ascends firstly;with the consolidation of soil, the depth of the neutral point becomes deeper;then the neutral point position is unaltered at the end of soil consolidation.%桩承式加筋路堤在高速公路软基处理中得到了广泛应用,但目前对其承载变形机制还缺乏深刻认识。结合南京长江第四大桥北接线段软基加固工程,基于数值方法对现浇 X 形桩桩承式加筋路堤中桩土沉降、桩土应力、桩身轴力及超静孔隙水压力的发展变化规律进行了分析。研究结果表明,受土拱效应影响,路堤填筑荷载主要由桩体承担,桩及桩间土土压力在路堤填筑过程中均逐渐增大,在软基固结过程中,桩顶土压力继续增大而桩间土土压力逐渐减小,最终趋于各自的稳定值;路堤填筑过程中桩身轴力增长较快,现浇X形桩桩身上部较大部分区段存在负摩阻力,桩身中性点位置经历了先逐渐上移、而后向下移动,最终趋于稳定的过程。

  19. Caste and Punishment : The Legacy of Caste Culture in Norm Enforcement

    OpenAIRE

    Hoff, Karla Ruth; Kshetramade, Mayuresh; Fehr, Ernst

    2009-01-01

    Well-functioning groups enforce social norms that restrain opportunism, but the social structure of a society may encourage or inhibit norm enforcement. This paper studies how the exogenous assignment to different positions in an extreme social hierarchy - the caste system - affects individuals' willingness to punish violations of a cooperation norm. Although the analysis controls for indi...

  20. Caste and wealth inequality in India

    OpenAIRE

    Zacharias, Ajit; Vakulabharanam, Vamsi

    2009-01-01

    In this paper, we conduct the novel exercise of analyzing the relationship between overall wealth inequality and caste divisions in India using nationally representative surveys on household wealth conducted during 1991–92 and 2002–03. According to our findings, the groups in India that are generally considered disadvantaged (known as Scheduled Castes or Scheduled Tribes) have, as one would expect, substantially lower wealth than the "forward" caste groups, while the Other Backward Classes an...

  1. Microdefects in cast multicrystalline silicon

    Energy Technology Data Exchange (ETDEWEB)

    Wolf, E.; Klinger, D.; Bergmann, S. [Inst. of Crystal Growth Berlin (Germany)

    1995-08-01

    The microdefect etching behavior of cast multicrystalline BAYSIX and SILSO samples is mainly the same as that of EFG silicon, in spite of the very different growth parameters applied to these two techniques and the different carbon contents of the investigated materials. Intentional decorating of mc silicon with copper, iron and gold did not influence the results of etching and with help of infrared transmission microscopy no metal precipitates at the assumed microdefects could be established. There are many open questions concerning the origin of the assumed, not yet doubtless proved microdefects.

  2. Solute distribution in columnar crystal zone of continuous casting billets

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    The periodic bending deformation in the direction of casting occurs at the liquid/solid interface of billet due to the roller supporting force and the pressure of molten metal in the process of continuous casting. Based on this fact, a qualitative expression of solute concentration in columnar crystal zone for continuous casting billet is established, which agrees with the experimental results basically. Therefore, it is favorable to gain a columnar structure with less segregation by adopting a caster with compactly distributed small rollers and enhancing the cooling intensity in secondary-cooling zone.

  3. Placed in homecare

    DEFF Research Database (Denmark)

    Glasdam, Stinne; Praestegaard, Jeanette; Henriksen, Nina

    2013-01-01

    Through a sociological case study this article analyses how, seen from a relational perspective, everyday life for elderly people receiving care in their own homes is lived with dependence on health-care professionals. The healthcare professionals’ time and tasks are assigned and allocated...... in advance so that the elderly people are neither allowed nor able to vary their response in relation to the situation they encounter. The life of the client is also treated as though it were a solid, structured everyday life with minimal private time. Work in the home, for example, household chores...... and personal care, resembles a disciplining strategy. The client lives under conditions of monitoring and control comparable to conditions of imprisonment. The client is subject to the will of and social intercourse with other people in his own home; he both knows it is necessary and offers resistance...

  4. Development and application of titanium alloy casting technology in China

    Institute of Scientific and Technical Information of China (English)

    NAN Hai; XIE Cheng-mu; ZHAO Jia-qi

    2005-01-01

    The development and research of titanium cast alloy and its casting technology, especially its application inaeronautical industry in China are presented. The technology of molding, melting and casting of titanium alloy, casting quality control are introduced. The existing problems and development trend in titanium alloy casting technology are also discussed.

  5. New trends in cold-chamber die casting machine design

    Institute of Scientific and Technical Information of China (English)

    R. Dańko; W. Kowalczyk

    2015-01-01

    Larger and larger proportions of aluminium castings, especial y those produced by the die casting process, can be observed during recent years in the automotive industry, house-hold articles and others. In case of the automotive industry, apart from the traditional elements produced by the die pressure method such as engine blocks or crank shaft bedplates, aluminium is displacing steel from structural parts of cars (‘body in white’). The current state and development directions of the structural solutions of cold-chamber die castings are analysed in this paper. These solutions drive the prospective development of these machines and die casting technology. The focus is mainly on essential functional systems such as:hydraulic drives of closing and locking units, as wel as pressing in die machines of known companies present on the European market.

  6. New trends in cold-chamber die casting machine design

    Directory of Open Access Journals (Sweden)

    R. Dańko

    2015-07-01

    Full Text Available Larger and larger proportions of aluminium castings, especially those produced by the die casting process, can be observed during recent years in the automotive industry, house-hold articles and others. In case of the automotive industry, apart from the traditional elements produced by the die pressure method such as engine blocks or crank shaft bedplates, aluminium is displacing steel from structural parts of cars (‘body in white’. The current state and development directions of the structural solutions of cold-chamber die castings are analysed in this paper. These solutions drive the prospective development of these machines and die casting technology. The focus is mainly on essential functional systems such as: hydraulic drives of closing and locking units, as well as pressing in die machines of known companies present on the European market.

  7. Solidified structure of thin-walled titanium parts by vertical centrifugal casting

    Directory of Open Access Journals (Sweden)

    Wu Shiping

    2011-05-01

    Full Text Available The solidified structure of the thin-walled and complicated Ti-6Al-4V castings produced by the vertical centrifugal casting process was studied in the present work. The results show that the wall thickness of the section is featured with homogeneously distributed fine equiaxial grains, compared with the microstructure of the thick-walled section. The grain size of the castings has a tendency to decrease gradually with the increasing of the centrifugal radius. The inter-lamellar space in thick-walled casting parts is bigger than that of the thin-walled parts, and the profile of inter-lamellar space is not susceptible to the centrifugal radius.

  8. Yield Improvement in Steel Casting (Yield II)

    Energy Technology Data Exchange (ETDEWEB)

    Richard A. Hardin; Christoph Beckermann; Tim Hays

    2002-02-18

    This report presents work conducted on the following main projects tasks undertaken in the Yield Improvement in Steel Casting research program: Improvement of Conventional Feeding and Risering Methods, Use of Unconventional Yield Improvement Techniques, and Case Studies in Yield Improvement. Casting trials were conducted and then simulated using the precise casting conditions as recorded by the participating SFSA foundries. These results present a statistically meaningful set of experimental data on soundness versus feeding length. Comparisons between these casting trials and casting trials performed more than forty years ago by Pellini and the SFSA are quite good and appear reasonable. Comparisons between the current SFSA feeding rules and feeding rules based on the minimum Niyama criterion reveal that the Niyama-based rules are generally less conservative. The niyama-based rules also agree better with both the trials presented here, and the casting trails performed by Pellini an d the SFSA years ago. Furthermore, the use of the Niyama criterion to predict centerline shrinkage for horizontally fed plate sections has a theoretical basis according to the casting literature reviewed here. These results strongly support the use of improved feeding rules for horizontal plate sections based on the Niyama criterion, which can be tailored to the casting conditions for a given alloy and to a desired level of soundness. The reliability and repeatability of ASTM shrinkage x-ray ratings was investigated in a statistical study performed on 128 x-rays, each of which were rated seven different times. A manual ''Feeding and Risering Guidelines for Steel Castings' is given in this final report. Results of casting trials performed to test unconventional techniques for improving casting yield are presented. These use a stacked arrangement of castings and riser pressurization to increase the casting yield. Riser pressurization was demonstrated to feed a casting up to

  9. Managerial Competence--Its Place in the Structure of University Teachers Competencies

    Science.gov (United States)

    Turturean Monica

    2012-01-01

    Higher education in Romania is passing though an authentic crisis caused by the necessity of our society to adapt to the European Union's demands. University teachers have a huge role in satisfying these requests. They need to possess a lot of competencies, and one of the most important is the managerial competency that will help university…

  10. Influence of Technological Parameters of Furane Mixtures on Shrinkage Creation in Ductile Cast Iron Castings

    Directory of Open Access Journals (Sweden)

    Vasková I.

    2014-10-01

    Full Text Available Ductile cast iron (GS has noticed great development in last decades and its boom has no analogue in history humankind. Ductile iron has broaden the use of castings from cast iron into areas, which where exclusively domains for steel castings. Mainly by castings, which weight is very high, is the propensity to shrinkage creation even higher. Shrinkage creation influences mainly material, construction of casting, gating system and mould. Therefore, the main realized experiment was to ascertain the influence of technological parameters of furane mixture on shrinkage creation in castings from ductile iron. Together was poured 12 testing items in 3 moulds forto determine and compare the impact of various technological parameters forms the propensity for shrinkage in the casting of LGG.

  11. Casting structure of pure aluminum by electric pulse modification at different superheated temperatures

    Institute of Scientific and Technical Information of China (English)

    Jingang Qi; Jianzhong Wang; Xingjiang Liu; Bing Wang; Daqiang Cang

    2005-01-01

    Electric pulse modification (EPM) is a novel technique that reduces grain size by altering the structure of a melt. It was investigated that the response of the casting structure of high pure aluminum to EPM in different superheated melts. The results indicate that the grain refining effect of a given pulse electric field holds an optimal temperature range, moreover, a lower or higher superheated temperature will both disadvantage the improvements of casting structure. It essentially lies in the cooperative action between the distorted absorption of clusters and the activated capability of atoms in the aluminum melt.

  12. Use of freeze-casting in advanced burner reactor fuel design

    Energy Technology Data Exchange (ETDEWEB)

    Lang, A. L.; Yablinsky, C. A.; Allen, T. R. [Dept. of Engineering Physics, Univ. of Wisconsin Madison, 1500 Engineering Drive, Madison, WI 53711 (United States); Burger, J.; Hunger, P. M.; Wegst, U. G. K. [Thayer School of Engineering, Dartmouth College, 8000 Cummings Hall, Hanover, NH 03755 (United States)

    2012-07-01

    This paper will detail the modeling of a fast reactor with fuel pins created using a freeze-casting process. Freeze-casting is a method of creating an inert scaffold within a fuel pin. The scaffold is created using a directional solidification process and results in open porosity for emplacement of fuel, with pores ranging in size from 300 microns to 500 microns in diameter. These pores allow multiple fuel types and enrichments to be loaded into one fuel pin. Also, each pore could be filled with varying amounts of fuel to allow for the specific volume of fission gases created by that fuel type. Currently fast reactors, including advanced burner reactors (ABR's), are not economically feasible due to the high cost of operating the reactors and of reprocessing the fuel. However, if the fuel could be very precisely placed, such as within a freeze-cast scaffold, this could increase fuel performance and result in a valid design with a much lower cost per megawatt. In addition to competitive costs, freeze-cast fuel would also allow for selective breeding or burning of actinides within specific locations in fast reactors. For example, fast flux peak locations could be utilized on a minute scale to target specific actinides for transmutation. Freeze-cast fuel is extremely flexible and has great potential in a variety of applications. This paper performs initial modeling of freeze-cast fuel, with the generic fast reactor parameters for this model based on EBR-II. The core has an assumed power of 62.5 MWt. The neutronics code used was Monte Carlo N-Particle (MCNP5) transport code. Uniform pore sizes were used in increments of 100 microns. Two different freeze-cast scaffold materials were used: ceramic (MgO-ZrO{sub 2}) and steel (SS316L). Separate models were needed for each material because the freeze-cast ceramic and metal scaffolds have different structural characteristics and overall porosities. Basic criticality results were compiled for the various models

  13. Theory of Cast Formation in Electrophoretic Deposition

    NARCIS (Netherlands)

    Biesheuvel, P. Maarten; Verweij, Henk

    1999-01-01

    The rate of cast formation in electrophoretic deposition is described by a combination of the equation of continuity for the suspension phase with expressions for the particle velocity and the movement of the cast-suspension boundary. The assumptions necessary to arrive at the well-known equations o

  14. Cardiovascular cast model fabrication and casting effectiveness evaluation in fetus with severe congenital heart disease or normal heart.

    Science.gov (United States)

    Wang, Yu; Cao, Hai-yan; Xie, Ming-xing; He, Lin; Han, Wei; Hong, Liu; Peng, Yuan; Hu, Yun-fei; Song, Ben-cai; Wang, Jing; Wang, Bin; Deng, Cheng

    2016-04-01

    To investigate the application and effectiveness of vascular corrosion technique in preparing fetal cardiovascular cast models, 10 normal fetal heart specimens with other congenital disease (control group) and 18 specimens with severe congenital heart disease (case group) from induced abortions were enrolled in this study from March 2013 to June 2015 in our hospital. Cast models were prepared by injecting casting material into vascular lumen to demonstrate real geometries of fetal cardiovascular system. Casting effectiveness was analyzed in terms of local anatomic structures and different anatomical levels (including overall level, atrioventricular and great vascular system, left-sided and right-sided heart), as well as different trimesters of pregnancy. In our study, all specimens were successfully casted. Casting effectiveness analysis of local anatomic structures showed a mean score from 1.90±1.45 to 3.60±0.52, without significant differences between case and control groups in most local anatomic structures except left ventricle, which had a higher score in control group (P=0.027). Inter-group comparison of casting effectiveness in different anatomical levels showed no significant differences between the two groups. Intra-group comparison also revealed undifferentiated casting effectiveness between atrioventricular and great vascular system, or left-sided and right-sided heart in corresponding group. Third-trimester group had a significantly higher perfusion score in great vascular system than second-trimester group (P=0.046), while the other anatomical levels displayed no such difference. Vascular corrosion technique can be successfully used in fabrication of fetal cardiovascular cast model. It is also a reliable method to demonstrate three-dimensional anatomy of severe congenital heart disease and normal heart in fetus.

  15. Energy use in selected metal casting facilities - 2003

    Energy Technology Data Exchange (ETDEWEB)

    Eppich, Robert E. [Eppich Technologies, Syracuse, IN (United States)

    2004-05-01

    This report represents an energy benchmark for various metal casting processes. It describes process flows and energy use by fuel type and processes for selected casting operations. It also provides recommendations for improving energy efficiency in casting.

  16. Hot ductility of continuously cast structural steels

    Energy Technology Data Exchange (ETDEWEB)

    Pytel, S.M. [Materials Science and Technology Institute, Cracow University of Technology, Cracow (Poland)

    1995-12-31

    The objective of this investigation was to explain the hot ductility of the structural steels characterized by different amount of carbon and morphology of sulfides. Two different rolling processes were simulated under computer controlled, high temperature deformation MTS system. Results of this study show that morphology of sulfides as well as temperature and amount of deformation are responsible for level of hot ductility of the steel tested. (author). 7 refs, 5 refs, 4 tabs.

  17. DEVELOPMENTS IN THE FIELD OF STEEL AND CAST IRON

    Directory of Open Access Journals (Sweden)

    E. B. Ten

    2013-01-01

    Full Text Available The article describes the use of a number of promising casting technologies applied to produce the castings of steel and cast iron with special properties. Such as, technology of centrifugal casting of large-size workpieces made of steel, forecasting method composition of slag in the smelting of high-manganese steels, method of complex modifying chromium cast irons, analysis of properties of perspective high-alloy aluminium cast iron.

  18. Remembering Places: Student Reliance on Place in Timed Essays

    Science.gov (United States)

    Evans, Donna

    2009-01-01

    This is the story of a research journey that follows the trail of a novel evaluand--"place." I examine place as mentioned by rising juniors in timed exams. Using a hybridized methodology--the qualitative approach of a hermeneutic dialectic process as described by Guba and Lincoln (1989), and the quantitative evidence of place mention--I query…

  19. Shrinkages in heavy-sized cast components of nodular cast iron – NDT and fatigue

    Directory of Open Access Journals (Sweden)

    Bleicher Christoph

    2014-06-01

    Full Text Available Material defects like shrinkages, dross, pores and chunky graphite are likely to occur in thick-walled castings and are a challenge for the foundries and their customers. These defects are mostly detected with handheld ultrasonic testing (UT or X-ray analysis. Within a research project done at the Fraunhofer Institute for Structural Durability and System Reliability LBF, the fatigue of Dross, shrinkages and chunky graphite in thick-walled cast material GGG-40 was estimated based on X-ray and fatigue tests on bending specimens. High fatigue reductions were received for the different material imperfections. Based on these impressions a further research project was executed at the Fraunhofer LBF to get an estimation of the informational value of UT in relation to fatigue of shrinkages in thick-walled castings of the material EN-GJS-400-18U-LT, EN-GJS-450-18 and EN-GJS-700-2. With the help of X-ray analysis and the UT technique Sampling Phased Array (SPA information about geometry and density were derived for a numerical analysis of shrinkages in thick-walled castings concerning fatigue. The following text summarizes the fatigue results achieved in the two research projects with the help of the X-ray and UT analysis.

  20. Structural and mechanical properties of 7075 alloy strips fabricated by roll-casting in a static magnetic field

    Science.gov (United States)

    Su, Xin; Xu, Guang-ming; Jiang, Jiu-wen

    2014-07-01

    The influences of a 0.2 T static magnetic field on the microstructure of 7075 aluminum alloys sheets produced with a twin-roll continuous caster at 675°C were investigated in this paper. Under a uniform magnetic field, the primary dendrites were refined and tended to be equiaxed. The microstructure consisted of an intermediate case between dendritic and equiaxed grains. Moreover, the use of an external static field in the twin-roll casting process can reduce heat discharge, resulting in a decrease in undercooling, and may also account for the abatement of segregation bands. In addition, the static magnetic field effectively improved the solute mixing capacity, and the added atoms more easily diffused from precipitates to the α-Al matrix, which resulted in an increase in the mechanical properties of the rolled sheets. Specimens prepared both in the presence of a static magnetic field and in the absence of a static magnetic field exhibited brittle-fracture characteristics.

  1. Structural and mechanical properties of 7075 alloy strips fabricated by roll-casting in a static magnetic field

    Institute of Scientific and Technical Information of China (English)

    Xin Su; Guang-ming Xu; Jiu-wen Jiang

    2014-01-01

    The influences of a 0.2 T static magnetic field on the microstructure of 7075 aluminum alloys sheets produced with a twin-roll continuous caster at 675°C were investigated in this paper. Under a uniform magnetic field, the primary dendrites were refined and tended to be equiaxed. The microstructure consisted of an intermediate case between dendritic and equiaxed grains. Moreover, the use of an external static field in the twin-roll casting process can reduce heat discharge, resulting in a decrease in undercooling, and may also account for the abatement of segregation bands. In addition, the static magnetic field effectively improved the solute mixing capacity, and the added atoms more easily diffused from precipitates to theα-Al matrix, which resulted in an increase in the mechanical properties of the rolled sheets. Specimens prepared both in the presence of a static magnetic field and in the absence of a static magnetic field exhibited brittle-fracture characteristics.

  2. Characterization of Technetium Speciation in Cast Stone

    Energy Technology Data Exchange (ETDEWEB)

    Um, Wooyong; Jung, Hun Bok; Wang, Guohui; Westsik, Joseph H.; Peterson, Reid A.

    2013-11-11

    This report describes the results from laboratory tests performed at Pacific Northwest National Laboratory (PNNL) for the U.S. Department of Energy (DOE) EM-31 Support Program (EMSP) subtask, “Production and Long-Term Performance of Low Temperature Waste Forms” to provide additional information on technetium (Tc) speciation characterization in the Cast Stone waste form. To support the use of Cast Stone as an alternative to vitrification for solidifying low-activity waste (LAW) and as the current baseline waste form for secondary waste streams at the Hanford Site, additional understanding of Tc speciation in Cast Stone is needed to predict the long-term Tc leachability from Cast Stone and to meet the regulatory disposal-facility performance requirements for the Integrated Disposal Facility (IDF). Characterizations of the Tc speciation within the Cast Stone after leaching under various conditions provide insights into how the Tc is retained and released. The data generated by the laboratory tests described in this report provide both empirical and more scientific information to increase our understanding of Tc speciation in Cast Stone and its release mechanism under relevant leaching processes for the purpose of filling data gaps and to support the long-term risk and performance assessments of Cast Stone in the IDF at the Hanford Site.

  3. Cholesterol in unusual places

    Energy Technology Data Exchange (ETDEWEB)

    Kucerka, N; Nieh, M P; Marquardt, D; Harroun, T A; Wassail, S R; Katsaras, J, E-mail: John.Katsaras@nrc.gc.ca, E-mail: Norbert.Kucerka@nrc.gc.ca

    2010-11-01

    Cholesterol is an essential component of mammalian cells, and is required for building and maintaining cell membranes, regulating their fluidity, and possibly acting as an antioxidant. Cholesterol has also been implicated in cell signaling processes, where it has been suggested that it triggers the formation of lipid rafts in the plasma membrane. Aside from cholesterol's physiological roles, what is also becoming clear is its poor affinity for lipids with unsaturated fatty acids as opposed to saturated lipids, such as sphingomyelin with which it forms rafts. We previously reported the location of cholesterol in membranes with varying degrees of acyl chain unsaturation as determined by neutron diffraction studies (Harroun et al 2006 Biochemistry 45, 1227; Harroun et al 2008 Biochemistry 47, 7090). In bilayers composed of phosphatidylcholine (PC) molecules with a saturated acyl chain at the sn-1 position or a monounsaturated acyl chain at both sn-1 and sn-2 positions, cholesterol was found in its much-accepted 'upright' position. However, in dipolyunsaturated 1,2-diarachidonyl phosphatidylcholine (20:4-20:4PC) membranes the molecule was found sequestered in the center of the bilayers. In further experiments, mixing l-palmitoyl-2-oleoyl phosphatidylcholine (16:0-18:1 PC) with 20:4-20:4PC resulted in cholesterol reverting to its upright orientation at approximately 40 mol% 16:0-18:1 PC. Interestingly, the same effect was achieved with only 5 mol% 1,2-dimyristoyl phosphatidylchoile (14:0-14:0PC).

  4. Caste in India, Past and Present

    Science.gov (United States)

    Bishop, Donald H.

    1971-01-01

    Traced is the sociocultural framework for the system in Indian culture which emphasized duty and obligations rather than individual freedom and rights. Also discussed are contemporary changes in the caste system. (DB)

  5. Low Background Micromegas in CAST

    CERN Document Server

    Garza, J G; Aznar, F.; Calvet, D.; Castel, J.F.; Christensen, F.E.; Dafni, T.; Davenport, M.; Decker, T.; Ferrer-Ribas, E.; Galán, J.; García, J.A.; Giomataris, I.; Hill, R.M.; Iguaz, F.J.; Irastorza, I.G.; Jakobsen, A.C.; Jourde, D.; Mirallas, H.; Ortega, I.; Papaevangelou, T.; Pivovaroff, M.J.; Ruz, J.; Tomás, A.; Vafeiadis, T.; Vogel, J.K.

    2015-01-01

    Solar axions could be converted into x-rays inside the strong magnetic field of an axion helioscope, triggering the detection of this elusive particle. Low background x-ray detectors are an essential component for the sensitivity of these searches. We report on the latest developments of the Micromegas detectors for the CERN Axion Solar Telescope (CAST), including technological pathfinder activities for the future International Axion Observatory (IAXO). The use of low background techniques and the application of discrimination algorithms based on the high granularity of the readout have led to background levels below 10$^{-6}$ counts/keV/cm$^2$/s, more than a factor 100 lower than the first generation of Micromegas detectors. The best levels achieved at the Canfranc Underground Laboratory (LSC) are as low as 10$^{-7}$ counts/keV/cm$^2$/s, showing good prospects for the application of this technology in IAXO. The current background model, based on underground and surface measurements, is presented, as well as ...

  6. Privileged Girls: The Place of Femininity and Femininity in Place

    Science.gov (United States)

    Fahey, Johannah

    2014-01-01

    Constructions of femininity and attendant notions of feminism are being produced in different ways in different places around the world. This is a complicated global process that cannot be reduced to analyses that take place in nation states. This paper seeks to respond to and enhance Angela McRobbie's compelling argument about understandings…

  7. Privileged Girls: The Place of Femininity and Femininity in Place

    Science.gov (United States)

    Fahey, Johannah

    2014-01-01

    Constructions of femininity and attendant notions of feminism are being produced in different ways in different places around the world. This is a complicated global process that cannot be reduced to analyses that take place in nation states. This paper seeks to respond to and enhance Angela McRobbie's compelling argument about understandings of…

  8. Effect of Some Parameters on the Cast Component Properties in Hot Chamber Die Casting

    Science.gov (United States)

    Singh, Rupinder; Singh, Harvir

    2016-04-01

    Hot chamber die casting process is designed to achieve high dimensional accuracy for small products by forcing molten metal under high pressure into reusable moulds, called dies. The present research work is aimed at study of some parameters (as a case study of spring adjuster) on cast component properties in hot chamber die casting process. Three controllable factors of the hot chamber die casting process (namely: pressure at second phase, metal pouring temperature and die opening time) were studied at three levels each by Taguchi's parametric approach and single-response optimization was conducted to identify the main factors controlling surface hardness, dimensional accuracy and weight of the casting. Castings were produced using aluminium alloy, at recommended parameters through hot chamber die casting process. Analysis shows that in hot chamber die casting process the percentage contribution of second phase pressure, die opening time, metal pouring temperature for surface hardness is 82.48, 9.24 and 6.78 % respectively. While in the case of weight of cast component the contribution of second phase pressure is 94.03 %, followed by metal pouring temperature and die opening time (4.58 and 0.35 % respectively). Further for dimensional accuracy contribution of die opening time is 76.97 %, metal pouring temperature is 20.05 % and second phase pressure is 1.56 %. Confirmation experiments were conducted at an optimal condition showed that the surface hardness, dimensional accuracy and weight of the castings were improved significantly.

  9. Solidification structures grown under induced flow and continuous casting of steel

    Science.gov (United States)

    Tsavaras, A. A.

    1984-01-01

    The use of induced flow as a means to control solidification structures in strand cast steel is investigated. The quality problems in strand cast steel stemming from columnar growth can be partially controlled, by Electro Magnetic Stirring (EMS). Induced flow changes the normal morphology of dendrites. Solids grown under intense stirring conditions show both negative and positive segregation which is considered unacceptable by some steel producers. The inclusion size and population is strongly affected by induced flow (EMS). Laboratory and industrial data show substantial reduction in inclusion size and content, but the overall effect of flow on inclusions is affected by the particular type of flow patterns utilized in each case. Productivity and quality are raised substantially in steel strand casting by utilizing EMS.

  10. Structural Changes Under Heat Treatment of High-Strength Cast Iron with Globular Graphite

    Science.gov (United States)

    Tsukanov, V. V.; Ziza, A. I.; Mikhailov, M. S.; Tsyganko, L. K.; Shandyba, G. A.

    2016-11-01

    High-strength cast iron of grade VCh50 with globular graphite is studied after isothermal quenching in the bainitic and martensitic ranges. The mechanical properties of the iron and the hardness of its structural components are determined. The fine structure of the iron with bainitic and martensitic matrix is studied. The effect of the tempering temperature after the isothermal quenching on the hardness and structure of the iron is estimated.

  11. Studies on the Condensed Structure of Vacuum Cast Atactic Polystyrene Films

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    The condensed structure of atactic-polystyrene(a-PS) films cast from the solutions of different concentrations in dichloromethane under vacuum and atmospheric conditions was studied bydifferential scanning calorimetry(DSC). It was found that only under vacuum evaporating conditions did the endothermic peak in the DSC curves of a-PS films depend on the concentration ofthe a-PS solution. For the samples cast from the solution of concentration below 0. 010 g/mL,no endothermal peak was observed, but for those cast from the solution of concentration above0. 020 g/mL, obvious endothermal peaks appeared. The onset of the endothermal peak is correlated with the critical overlapping concentration c* (0. 010-0. 020 g/mL), which is in agreement with the theoretically calculated one (c*cal=0. 014 g/mL).

  12. Simulation of the ingot extraction in the continuous casting process

    Directory of Open Access Journals (Sweden)

    J. Szajnar

    2011-07-01

    Full Text Available Cast ingot pulling speed is significantly affecting the nature of the resulting structure and the quality of the outer surface of the ingot. By introducing a variable algorithm for extraction of the ingot we may to some extent control the shape and location of the solid / liquid interface and temperature field in the cross-section of the ingot. The shape of the crystallization front, as well as its position relative to mold plays an important role in the process of continuous casting ingots of grey iron and affects the structure of the casting. In order to verify the impact of an algorithm on the shape and the location of solid / liquid interface, a number of simulations in ANSYS Fluent 12 were made, for determining the shape of crystallization front and temperature distribution on the cross-section of the ingot.

  13. Strategies for Aging in Place

    Directory of Open Access Journals (Sweden)

    Suzanne Dupuis-Blanchard

    2015-01-01

    Full Text Available For healthy and independent older adults, aging in place can be seen as identical to any other adult living at home. Little is known about how frail seniors, particularly those who speak a minority language, manage the challenges of aging in place. The present qualitative descriptive study explores the strategies that Canadian French-speaking seniors have put in place to counter their loss of independence and promote their ability to stay in their home. Semistructured individual interviews were conducted with 39 older adults and transcribed, followed by content analysis to identify common themes related to study objectives. Six themes emerged in response to strategies described for aging in place. Findings reveal the limited extent to which language issues were perceived as a barrier by participants. In conclusion, the results of this study provide us with fruitful insights to guide community nursing practice, future research, and public policy.

  14. Vermicular cast iron production in the “Inmold” technology (in the Metalpol casting house and the assessment of its thermal fatigue resistance

    Directory of Open Access Journals (Sweden)

    J. Zych

    2011-07-01

    Full Text Available The method of obtaining the vermicular cast iron in the “Inmold” technology and the results of the thermal fatigue investigations, are presented in the paper. The influence of the maximum cycle temperature (Tmax on the thermal fatigue resistance was examined by means of the L.F. Coffin method. The cast iron structure change caused by the thermal fatigue is presented in the paper. When the vermicular cast iron is subjected to the thermal fatigue the matrix ferritisation occurs, which leads to the strength, Rm., decrease. The heating process of the vermicular cast iron is slower as compared to the spheroidal cast iron, whereas the cooling process is faster. Under the same conditions of heat exchanging the vermicular cast iron is heated to a much lower temperature than the spheroidal one. Together with the maximum heating temperature increase the thermal fatigue resistance decreases.

  15. Colour Metallography of Cast Iron

    Institute of Scientific and Technical Information of China (English)

    Zhou Jiyang; Liu Jincheng

    2011-01-01

    White Cast Iron (Ⅰ) White cast iron or ‘white iron' refers to the type of cast iron in which all of the carbon exists as carbide;there is no graphite in the as-cast structure and the fractured surface shows a white colour.White cast iron can be divided in three classes:· Normal white cast iron — this iron contains only C,Si,Mn,P and S,with no other alloying elements.· Low-alloy white cast iron — the total mass fraction of alloying elements is less than 5%.

  16. Control of chilling tendency in grey cast iron reuse

    Directory of Open Access Journals (Sweden)

    Saliu Ojo Seidu

    2013-02-01

    Full Text Available In grey cast iron remelt and recycling, white iron can result in the cast product if careful control of the chilling tendency is not ensured. Many jobbing foundries are constrained in furnace types and available foundry additives that the operation always results in white irons. This study is towards ensuring grey iron is reproduced from cast iron scrap auto engine blocks, when using a diesel fired rotary furnace and a FeSi alloy for structural modification (inoculation. With varying addition rate of the FeSi alloy to the tapped molten metal, chill wedge tests were performed on two different wedge samples of type W (according to ASTM A367- wedge test with cooling modulus of 0.45 cm (W3½ and 0.54 cm (W4. The carbon equivalents for the test casts were within hypoeutectic range (3.85 wt. (% to 4.11 wt. (%. In the W4 wedge sample, at 2.0 wt. (% addition rate of the FeSi alloy, the relative clear chill was totally reduced to zero from 19.76%, while the relative mottled chill was brought down to 9.59% from 33.71%. The microstructure from the cast at this level of addition was free of carbidic phases; it shows randomly oriented graphite flakes evenly distributed in the iron matrix. Hardness assessment shows that increasing rate of FeSi addition results in decreasing hardness, with maximum effect at 2.0 wt. (% addition. With equivalent aspect ratio (cooling modulus in a target cast product, this addition rate for this FeSi alloy under this furnace condition will attain graphitized microstructure in the cast product.

  17. Control of chilling tendency in grey cast iron reuse

    Directory of Open Access Journals (Sweden)

    Saliu Ojo Seidu

    2012-01-01

    Full Text Available In grey cast iron remelt and recycling, white iron can result in the cast product if careful control of the chilling tendency is not ensured. Many jobbing foundries are constrained in furnace types and available foundry additives that the operation always results in white irons. This study is towards ensuring grey iron is reproduced from cast iron scrap auto engine blocks, when using a diesel fired rotary furnace and a FeSi alloy for structural modification (inoculation. With varying addition rate of the FeSi alloy to the tapped molten metal, chill wedge tests were performed on two different wedge samples of type W (according to ASTM A367- wedge test with cooling modulus of 0.45 cm (W3½ and 0.54 cm (W4. The carbon equivalents for the test casts were within hypoeutectic range (3.85 wt. (% to 4.11 wt. (%. In the W4 wedge sample, at 2.0 wt. (% addition rate of the FeSi alloy, the relative clear chill was totally reduced to zero from 19.76%, while the relative mottled chill was brought down to 9.59% from 33.71%. The microstructure from the cast at this level of addition was free of carbidic phases; it shows randomly oriented graphite flakes evenly distributed in the iron matrix. Hardness assessment shows that increasing rate of FeSi addition results in decreasing hardness, with maximum effect at 2.0 wt. (% addition. With equivalent aspect ratio (cooling modulus in a target cast product, this addition rate for this FeSi alloy under this furnace condition will attain graphitized microstructure in the cast product.

  18. Solidification Structure and Macrosegregation of Billet Continuous Casting Process with Dual Electromagnetic Stirrings in Mold and Final Stage of Solidification: A Numerical Study

    Science.gov (United States)

    Jiang, D.; Zhu, M.

    2016-12-01

    Coupling macroscale heat transfer and fluid flow with microscale grain nucleation and crystal growth, a mixed columnar-equiaxed solidification model was established to study the SWRT82B steel solidification structure and macrosegregation in 160 mm × 160 mm billet continuous casting with dual electromagnetic stirrings in mold and final stage of solidification (M-EMS and F-EMS). In the model, the phases of liquid, columnar, and equiaxed were treated separately and the initial growing equiaxed phase, which could move freely with liquid, was regarded as slurry. To obtain the equiaxed grains nucleation and columnar front evolution, the unit tracking method and the columnar front tracking model were built. The model was validated by magnetic induction intensity of stirrer, billet surface temperature, and carbon segregation. The equiaxed phase evolution and the solute transport with effect of fluid flow and grains transport were described in this article. The results show that the equiaxed phase ratio will not increase obviously with higher current intensity of M-EMS, while the negative segregation near the strand surface becomes more serious. The negative segregation zone near the billet center and the center positive segregation come into being with the effect of equiaxed grains sedimentation and liquid thermosolutal flow. It is also found that the liquid solute transport in the F-EMS zone becomes the main factor with higher current intensity rather than the solidification rate, and therefore, the final billet center segregation decreases first and then turns to rise with the current intensity. The optimal current intensities of M-EMS and F-EMS proposed for SWRT82B billet continuous casting are 200 and 400 A, respectively.

  19. Solidification Structure and Macrosegregation of Billet Continuous Casting Process with Dual Electromagnetic Stirrings in Mold and Final Stage of Solidification: A Numerical Study

    Science.gov (United States)

    Jiang, D.; Zhu, M.

    2016-08-01

    Coupling macroscale heat transfer and fluid flow with microscale grain nucleation and crystal growth, a mixed columnar-equiaxed solidification model was established to study the SWRT82B steel solidification structure and macrosegregation in 160 mm × 160 mm billet continuous casting with dual electromagnetic stirrings in mold and final stage of solidification (M-EMS and F-EMS). In the model, the phases of liquid, columnar, and equiaxed were treated separately and the initial growing equiaxed phase, which could move freely with liquid, was regarded as slurry. To obtain the equiaxed grains nucleation and columnar front evolution, the unit tracking method and the columnar front tracking model were built. The model was validated by magnetic induction intensity of stirrer, billet surface temperature, and carbon segregation. The equiaxed phase evolution and the solute transport with effect of fluid flow and grains transport were described in this article. The results show that the equiaxed phase ratio will not increase obviously with higher current intensity of M-EMS, while the negative segregation near the strand surface becomes more serious. The negative segregation zone near the billet center and the center positive segregation come into being with the effect of equiaxed grains sedimentation and liquid thermosolutal flow. It is also found that the liquid solute transport in the F-EMS zone becomes the main factor with higher current intensity rather than the solidification rate, and therefore, the final billet center segregation decreases first and then turns to rise with the current intensity. The optimal current intensities of M-EMS and F-EMS proposed for SWRT82B billet continuous casting are 200 and 400 A, respectively.

  20. Analysis of the Effect of Cast-in-situ Floor Slab on the Seismic Performance of Frame Structure%考虑现浇楼板影响的框架结构抗震性能分析

    Institute of Scientific and Technical Information of China (English)

    应乘风; 唐兴荣

    2014-01-01

    为了研究现浇楼板对钢筋混凝土框架结构抗震性能的影响,文章利用 pushover 方法对3个钢筋混凝土框架结构模型进行了分析研究,包括不考虑现浇楼板、考虑现浇楼板以及考虑现浇楼板钢筋影响的空间框架结构。通过对计算结果进行分析比较得出一些结论,并对框架结构抗震设计给出一些建议,提出考虑楼板影响的框架结构抗震设计方法,可供实际框架结构设计时参考。%To study the effect of cast-in-situ floor slab on the seismic performance of reinforced con-crete frame structure,three reinforced concrete frame structure models were analyzed by pushover analysis in this paper,the first with no considering the effect of cast-in-situ floor slab,the second considering the effect of cast-in-situ floor slab,and the third considering the effect of cast-in-situ floor slab steel.Conclusions were obtained by analyzing and comparing the results and frame structure seismic design suggestions were pro-posed.The seismic design method with considering the effect of the cast-in-situ floor slab on frame structure was proposed to be referred in the actual frame structure design.

  1. Development of electroslag metallurgy and casting in China

    Institute of Scientific and Technical Information of China (English)

    2004-01-01

    The electroslag metallurgy has been developed since 1958. At present, all special steel plants have constructed electroslag metallurgical workshops. There are 86 Electroslag Remelting (ESR) furnaces in these steel plants with annual capacity of 100 000 tons. The products by ESR include 243 designations of steel and superalloy. The Chinese metallurgists have made significant achievements in the type and structure of electroslag remelting furnaces, eletroslag remelting technology, shaped castings by Electroslag Remelting Casting (ESRC), the manufacture of large-size ingots by ESR and the study of ESR mechanism. These achievements have already been recognized by foreign metallurgists.

  2. Structure and mechanical properties of improved cast stainless steels for nuclear applications

    Science.gov (United States)

    Kenik, E. A.; Busby, J. T.; Gussev, M. N.; Maziasz, P. J.; Hoelzer, D. T.; Rowcliffe, A. F.; Vitek, J. M.

    2017-01-01

    Casting of stainless steels is a promising and cost saving way of directly producing large and complex structures, such a shield modules or divertors for the ITER. In the present work, a series of modified high-nitrogen cast stainless steels has been developed and characterized. The steels, based on the cast equivalent of the composition of 316 stainless steel, have increased N (0.14-0.36%) and Mn (2-5.1%) content; copper was added to one of the heats. Mechanical tests were conducted with non-irradiated and 0.7 dpa neutron irradiated specimens. It was established that alloying by nitrogen significantly improves the yield stress of non-irradiated steels and the deformation hardening rate. Manganese tended to decrease yield stress but increased radiation hardening. The role of copper on mechanical properties was negligibly small. Analysis of structure was conducted using SEM-EDS and the nature and compositions of the second phases and inclusions were analyzed in detail. No ferrite formation or significant precipitation were observed in the modified steels. It was shown that the modified steels, compared to reference material (commercial cast 316L steel), had better strength level, exhibit significantly reduced elemental inhomogeneity and only minor second phase formation.

  3. Large structural, thin-wall castings made of metals subject to hot tearing, and their fabrication

    Science.gov (United States)

    Smashey, Russell W. (Inventor)

    2001-01-01

    An article, such as a gas turbine engine mixer, is made by providing a mold structure defining a thin-walled, hollow article, and a base metal that is subject to hot tear cracking when cast in a generally equiaxed polycrystalline form, such as Rene' 108 and Mar-M247. The article is fabricated by introducing the molten base metal into the mold structure, and directionally solidifying the base metal in the mold structure to form a directionally oriented structure. The directionally oriented structure may be formed of a single grain or oriented multiple grains.

  4. A Novel Process in Semi-Solid Metal Casting

    Institute of Scientific and Technical Information of China (English)

    Bijan Abbasi-Khazaei; Saeid Ghaderi

    2012-01-01

    In this research a new process for semi-solid casting of ductile iron based on the high nucleation rate combined with locally mechanical stirring is presented. In this process at first fully liquid ductile iron was poured on the peripheral surface of a wheel rotating against pouring direction. At this stage, the solid crystals nucleated at the chilling surface were pushed to the melt by a heat resistance steel cutter and finally the semi-solid slurry was generated. Reheating treatment was done on the samples to achieve more efficiency of semi-solid casting process. The effects of the travelling distance of solid particles during casting, the reheating time and temperature were examined. The results showed that the process effectively changes the dendrite structure to globular one.

  5. Maintenance system improvement in cast iron foundry

    Directory of Open Access Journals (Sweden)

    S. Kukla

    2011-07-01

    Full Text Available The work presents the issue of technical equipment management in an iron foundry basing on the assumptions of the TPM system (Total Productive Maintenance. Exploitation analysis of automatic casting lines has been carried out and their work’s influence on the whole production system’s functioning has been researched. Within maintenance system improvement, implementation of autonomic service and planned lines’ review have been proposed in order to minimize the time of breakdown stoppages. The SMED method was used to optimize changeover time, and the OEE (Overall Equipment Effectiveness was applied to evaluate the level of resources usage before and after implementing changes. Further, the influence of the maintenance strategy of casting devices’ efficiency on own costs of casting manufac- ture was estimated.

  6. Effect of molybdenum, vanadium, boron on mechanical properties of high chromium white cast iron in as-cast condition

    Science.gov (United States)

    Nurjaman, F.; Sumardi, S.; Shofi, A.; Aryati, M.; Suharno, B.

    2016-02-01

    In this experiment, the effect of the addition carbide forming elements on high chromium white cast iron, such as molybdenum, vanadium and boron on its mechanical properties and microstructure was investigated. The high chromium white cast iron was produced by casting process and formed in 50 mm size of grinding balls with several compositions. Characterization of these grinding balls was conducted by using some testing methods, such as: chemical and microstructure analysis, hardness, and impact test. From the results, the addition of molybdenum, vanadium, and boron on high chromium white cast iron provided a significant improvement on its hardness, but reduced its toughness. Molybdenum induced fully austenitic matrix and Mo2C formation among eutectic M7C3 carbide. Vanadium was dissolved in the matrix and carbide. While boron was played a role to form fine eutectic carbide. Grinding balls with 1.89 C-13.1 Cr-1.32 Mo-1.36 V-0.00051 B in as-cast condition had the highest hardness, which was caused by finer structure of eutectic carbide, needle like structure (upper bainite) matrix, and martensite on its carbide boundary.

  7. METHODS OF RECEIVING OF FINE-GRAINED STRUCTURE OF CASTINGS AT CRYSTALLIZATION

    Directory of Open Access Journals (Sweden)

    N. K. Tolochko

    2012-01-01

    Full Text Available The article deals with methods for fine-grained structure of ingots during crystallization depending on the used foundry technologies. It is shown that by using modern scientific and technological advances may improve the traditional and the development of new casting processes, providing production of cast parts with over fine-grained structure and enhanced properties.

  8. Thermodynamic stability of austenitic Ni-Mn-Cu cast iron

    Directory of Open Access Journals (Sweden)

    A. Janus

    2014-07-01

    Full Text Available The performed research was aimed at determining thermodynamic stability of structures of Ni-Mn-Cu cast iron castings. Examined were 35 alloys. The castings were tempered at 900 °C for 2 hours. Two cooling speeds were used: furnace-cooling and water-cooling. In the alloys with the nickel equivalent value less than 20,0 %, partial transition of austenite to martensite took place. The austenite decomposition ratio and the related growth of hardness was higher for smaller nickel equivalent value and was clearly larger in annealed castings than in hardened ones. Obtaining thermodynamically stable structure of castings requires larger than 20,0 % value of the nickel equivalent.

  9. The deformation of wax patterns and castings in investment casting technology

    Directory of Open Access Journals (Sweden)

    A. Herman

    2012-01-01

    Full Text Available The dimensional accuracy of the final casting of Inconel alloy 738 LC is affected by many aspects. One of them is the choice of method and time of cooling wax model for precision investment casting. The main objective was to study the initial deformation of the complex shape of the casting of the rotor blades. Various approaches have been tested for cooling wax pattern. When wax models are cooling on the air, without clamping in jig for cooling, deviations from the ideal shape of the casting are very noticeable (up to 8 mm and most are in extreme positions of the model. When blade is cooled in fixing jig in water environment, the resulting deviations compared with cooling in air are significantly larger, sometimes up to 10 mm. This itself does not mean that the final shape of the casting is dimensionally more accurate with usage of wax models, which have deviations from the ideal position smaller. Another deformation occurs when shell mould is produced around wax pattern and furthermore deformations emerge while casting of blade is cooling. This paper demonstrates first steps in describing complex process of deformations of Inconel alloy blades produced with investment casting technology by comparing results from thermal imagery, simulations in foundry simulation software ProCAST 2010 and measurements from CNC scanning system Carl Zeiss MC 850. Conclusions are so far not groundbreaking, but it seems deformations of wax pattern and deformations of castings do in some cases cancel each other by having opposite directions. Describing entirely whole process of deformations will help increase precision of blade castings so that models at the beginning and blades in the end are the same.

  10. Unique morphology of intratubular light chain casts in multiple myeloma: The amyloid cast nephropathy

    Directory of Open Access Journals (Sweden)

    Alok Sharma

    2014-01-01

    Full Text Available Cast nephropathy is the most frequent pattern of renal involvement in multiple myeloma characterized by presence of tubular casts with characteristic morphology that are composed of monotypic (either kappa or lambda light chains as seen by immunofluorescence microscopy. Rarely these casts may show evidence of amyloidogenesis and assume a unique morphology, which needs to be appreciated for arriving at accurate diagnosis. We present the case of an elderly male presenting with features of acute kidney injury and detected with extensive inspissation of intratubular casts with lambda light chain restriction and a unique morphology with spiculated congophilic periphery. Further investigations confirmed the presence of systemic myeloma. Presence of intratubular amyloid casts is a rare occurrence which needs to be recognized by the pathologist and forms a vital element in timely diagnosis of the systemic disease which often presents with renal involvement.

  11. Genetic evidence on the origins of Indian caste populations.

    Science.gov (United States)

    Bamshad, M; Kivisild, T; Watkins, W S; Dixon, M E; Ricker, C E; Rao, B B; Naidu, J M; Prasad, B V; Reddy, P G; Rasanayagam, A; Papiha, S S; Villems, R; Redd, A J; Hammer, M F; Nguyen, S V; Carroll, M L; Batzer, M A; Jorde, L B

    2001-06-01

    The origins and affinities of the approximately 1 billion people living on the subcontinent of India have long been contested. This is owing, in part, to the many different waves of immigrants that have influenced the genetic structure of India. In the most recent of these waves, Indo-European-speaking people from West Eurasia entered India from the Northwest and diffused throughout the subcontinent. They purportedly admixed with or displaced indigenous Dravidic-speaking populations. Subsequently they may have established the Hindu caste system and placed themselves primarily in castes of higher rank. To explore the impact of West Eurasians on contemporary Indian caste populations, we compared mtDNA (400 bp of hypervariable region 1 and 14 restriction site polymorphisms) and Y-chromosome (20 biallelic polymorphisms and 5 short tandem repeats) variation in approximately 265 males from eight castes of different rank to approximately 750 Africans, Asians, Europeans, and other Indians. For maternally inherited mtDNA, each caste is most similar to Asians. However, 20%-30% of Indian mtDNA haplotypes belong to West Eurasian haplogroups, and the frequency of these haplotypes is proportional to caste rank, the highest frequency of West Eurasian haplotypes being found in the upper castes. In contrast, for paternally inherited Y-chromosome variation each caste is more similar to Europeans than to Asians. Moreover, the affinity to Europeans is proportionate to caste rank, the upper castes being most similar to Europeans, particularly East Europeans. These findings are consistent with greater West Eurasian male admixture with castes of higher rank. Nevertheless, the mitochondrial genome and the Y chromosome each represents only a single haploid locus and is more susceptible to large stochastic variation, bottlenecks, and selective sweeps. Thus, to increase the power of our analysis, we assayed 40 independent, biparentally inherited autosomal loci (1 LINE-1 and 39 Alu elements

  12. Valence electron structure of cast iron and graphltization behaviour criterion of elements

    Institute of Scientific and Technical Information of China (English)

    刘志林; 李志林; 孙振国; 杨晓平; 陈敏

    1995-01-01

    The valence electron structure of common alloy elements in phases of cast iron is calculated- The relationship between the electron structure of alloy elements and equilibrium, non-equilibrium solidification and graphitization is revealed by defining the bond energy of the strongest bond in a phase as structure formation factor S. A criterion of graphitization behaviour of elements is advanced with the critical value of the structure formation factor of graphite and the n of the strongest covalent bond in cementite. It is found that this theory conforms to practice very well when the criterion is applied to the common alloy elements.

  13. Mathematical Modelling of the Thermical Regime in the Continous Casting Process

    Directory of Open Access Journals (Sweden)

    Monika Erika POPA

    2005-10-01

    Full Text Available Continuous casting is one of the prominent methods of production of casts. Effective design and operation of continuous casting machines needs complete analysis of the continuous casting process. In this paper the basic principles of continuous casting and its heat transfer analysis using the finite element method are presented. In the analysis phase change is assumed to take place at constant temperature. A front tracking algorithm has been developed to predict the position of the solidification front at each step. Finally, examples that are solved by the proposed algorithm are discussed. The results show that there is a good agreement between the method developed in this work and other previously reported works.

  14. Numerical Simulation of Casting Deformation and Stress in the Ti-Alloy Parts with Framework Structure%钛合金框架铸件铸造变形和应力的数值模拟

    Institute of Scientific and Technical Information of China (English)

    崔新鹏; 张晨; 范世玺; 南海

    2015-01-01

    基于ProCAST软件对框架型钛合金铸件铸造过程中的温度场、应力场及铸造变形进行了数值模拟。在应力计算初期将石墨型壳设为RIGID模型,后期设为VACANT模型。模拟结果显示铸件上部及内部框架处温度较低,下部浇道处温度较高;铸件两侧尖部有沿-Y方向的弯曲变形;内部框架结构的转角处会出现应力集中。实际尺寸测量结果与模拟结果吻合较好,验证了模拟的准确性。%The temperature field,stress field and casting deformation of the Ti-Alloy framework castings during pouring and solidification process were simulated based on the ProCAST software.The model of the graphite mould was set as RIGID at the initial stage of the stress calculation whereas VACANT at the later stage.The simulation results reveal that the temperature of the upper and inner part of the framework castings is much lower than the one of the bottom part and the pouring gates.The bending deflection along -Y axis was observed at two tips of the framework castings.Stress concentration was observed at the corners of the internal framework structure.The actual casting dimension measurement results are well in agreement with the simulated ones,which virified the accuracy of the simulation.

  15. Unusually well preserved casts of halite crystals: A case from the Upper Frasnian of northern Lithuania

    Science.gov (United States)

    Rychliński, Tomasz; Jaglarz, Piotr; Uchman, Alfred; Vainorius, Julius

    2014-07-01

    Upper Frasnian carbonate-siliciclastics of the Stipinai Formation (northern Lithuania) comprise a bed of calcareous silty arenite with casts of halite crystals, including hopper crystals. Unusually well-preserved casts occur on the lower surface of the bed, while poorly-preserved casts are present on the upper bedding surface. The casts originated as the result of the dissolution of halite crystals which grew in the sediment. The dissolution took place during early stages of diagenesis, when host sediment was soft. Unstable cavities after crystal dissolution were filled by overlying sediment forming their casts. The collapsing sediment form sink-hole deformation structures which disturb wave-ripple cross lamination from the upper part of the bed. Dewatering pipe structures are also present. The casts and accompanying sink-hole and dewatering pipes are classified as the postdepositional deformation structures caused by haloturbation.

  16. Assessments of Population Structure, Diversity, and Phylogeography of the Swiss Needle Cast Fungus (Phaeocryptopus gaeumannii in the U.S. Pacific Northwest

    Directory of Open Access Journals (Sweden)

    Patrick Bennett

    2016-01-01

    Full Text Available Swiss needle cast (SNC is a foliar disease of Douglas-fir (Pseudotsuga menziesii caused by Phaeocryptopus gaeumannii (Rohde Petrak. This fungus is endemic to western North America, where it has historically had little impact in native forests. However, increasing disease severity in western Oregon since the 1990s has prompted renewed interest in P. gaeumannii and SNC. For this study, we analyze multilocus microsatellite genotypes from 482 single-spore isolates from 68 trees across 14 sites in the western Coast Range of Oregon and southwestern Washington. This study assesses genotypic variation and genetic structure at several levels of population hierarchy. Despite the observation that most of the genetic variation occurred within subpopulations, our analyses detected significant differentiation at all hierarchical levels. Clustering among the 482 isolates based on genetic distance clearly supports the existence of two previously described cryptic lineages of P. gaeumannii in the western United States. The two lineages occur in varying proportions along latitudinal and longitudinal gradients in western Oregon and Washington, suggesting a relationship between climate and phylogeography. Sites near Tillamook, Oregon, where SNC is most severe, consist of sympatric subpopulations in which the two lineages comprise roughly equal proportions.

  17. Prediction of porosity in cast equiaxed alloy 718

    Energy Technology Data Exchange (ETDEWEB)

    Ko, Y.K. [Univ. of Alabama, Tuscaloosa, AL (United States); Sahai, V.; Overfelt, R.A. [Auburn Univ., AL (United States); Berry, J.T. [Mississippi State Univ., MS (United States)

    1995-12-31

    The prediction of porosity distribution in shaped castings is a popular topic at the present time. A number of criteria functions (CFs) have been proposed to assist in such predictions, these functions generally being obtained from computer modeling of solidification. Although considerable attention has been given to the use of CFs with plain carbon steel and aluminum castings, only limited attention has been given to superalloy castings. Using experimental data on porosity distribution in such castings for validation, various criteria functions were compared for effectiveness in predicting the level of porosity in castings of different thicknesses vacuum investment cast in alloy 718. The criteria functions concerned were obtained by interrogating the output of a simulation using commercially available software. The castings were in the form of vertically cast plates attached to a common top gating system. The problems associated with obtaining thermally accurate simulation, as well as appropriate validation are also discussed.

  18. Bryce Canyon National Park: Hoodoos Cast Their Spell. Teaching with Historic Places.

    Science.gov (United States)

    Shakespear, Mala

    Surrounded by the beauty of southern Utah and panoramic views of three states, filigrees of colorful stones that erosion has shaped into a spectacular array of spires, fins, and pinnacles called "hoodoos" remind tourist viewers of church steeples, Gothic spires, castle walls, animals, and even people. In this lesson students explore why…

  19. Role of Titanium in Thin Wall Vermicular Graphite Iron Castings Production

    Directory of Open Access Journals (Sweden)

    M. Górny

    2013-04-01

    Full Text Available In this paper the effects of titanium addition in an amount up to 0.13 wt.% have been investigated to determine their effect on the microstructure and mechanical properties of Thin Wall Vermicular Graphite Iron Castings (TWVGI. The study was performed for thinwalled iron castings with 3-5 mm wall thickness and for the reference casting with 13 mm. Microstructural changes were evaluated by analyzing quantitative data sets obtained by image analyzer and also using scanning electron microscope (SEM. Metallographic examinations show that in thin-walled castings there is a significant impact of titanium addition to vermicular graphite formation. Thinwalled castings with vermicular graphite have a homogeneous structure, free of chills, and good mechanical properties. It may predispose them as a potential use as substitutes for aluminum alloy castings in diverse applications.

  20. Is caste destiny? Occupational diversification among Dalits in rural India

    OpenAIRE

    Gang, Ira N.; Sen, Kunal; Yun, Myeong-Su

    2012-01-01

    The caste system - a system of elaborately stratified social hierarchy - distinguishes India from most other societies. Among the most distinctive factors of the caste system is the close link between castes and occupations, especially in rural India, with Dalits or Scheduled Castes (SC) clustered in occupations that were the least well paid and most degrading in terms of manual labour. Along with the Scheduled Tribes (STs), the SCs have the highest incidence of poverty in India, with poverty...

  1. Fermilab joins in global live Web cast

    CERN Multimedia

    Polansek, Tom

    2005-01-01

    From 2 to 3:30 p.m., Lederman, who won the Nobel Prize for physics in 1988, will host his own wacky, science-centered talk show at Fermi National Accelerator Laboratory as part of a lvie, 12-hour, international Web cast celebrating Albert Einstein and the world Year of Physics (2/3 page)

  2. Considering place in community health nursing.

    Science.gov (United States)

    Bender, Amy; Clune, Laurie; Guruge, Sepali

    2007-09-01

    When a geographic location is assigned meaning, it becomes a place. The authors argue that place matters as both geographical location and lived experience. They extend the current conceptualization of nursing geography to encompass community health nursing and address intricacies of community nursing practice and research that often go unnoticed. They do so by exploring the notion of place in home and community, including the structural/spatial dimensions of the nurse-client relationship. The authors review the health geography literatures, then discuss the implications for practice and research in community health. They invite community health nurses to critically examine their practice and research with reference to such issues as the power of the nurse, marginalized places as determinants of health, and how best to care for clients living in diverse community settings.

  3. Caste dominance and economic performance in rural India

    NARCIS (Netherlands)

    Kalwij, Adriaan; Iversen, Vegard; Verschoor, Arjan; Dubey, Amaresh

    2014-01-01

    Using household panel data for rural India covering 1993–94 and 2004–5, we test whether scheduled castes (SCs) and other minority groups perform better or worse in terms of income when resident in villages dominated by (i) upper castes or (ii) their own group. Theoretically, upper-caste dominance co

  4. Investigation of Oxide Bifilms in Investment Cast Superalloy IN100: Part II. Characterization

    Science.gov (United States)

    Kaplan, Max A.; Fuchs, Gerhard E.

    2016-05-01

    Oxide bifilms are a proposed casting inclusion reported to have been observed in vacuum investment cast polycrystalline Ni-based superalloys. Ongoing research seeks to determine if current superalloy casting practices can result in the formation of oxide bifilms, and subsequently if it is possible to observe and characterize this phenomenon. The effect of casting atmosphere, turbulence, filtering, hot isostatic pressing, and heat treatment has been investigated to identify the critical parameters that have been reported to result in bifilm formation in Ni-based superalloy IN100. Scanning Auger microscopy (SAM), scanning electron microscopy (SEM), and high-resolution transmission electron microscopy (HR-TEM) were utilized to characterize samples from each casting condition. In situ ultrahigh vacuum Auger fractography did not indicate the presence of bifilms on the fracture behavior of IN100 in any processing condition. SAM analysis identified a sulfur-enriched monolayer on the surface of dendritic casting porosity, and identified heterogeneous Ti oxycarbide inclusions in air cast IN100. SEM analysis also indicated the presence of Ti oxycarbide inclusions in air cast IN100, and determined that these inclusion structures consist of fine blocky external M(Ti, Mo)C carbide enveloping an internal core of alumina. HR-TEM analysis indicated that none of the oxycarbide inclusion interfaces exist as discontinuous unbound interfaces, and that the internal alumina core is an ultra-fine polycrystalline structure.

  5. Effects of slope plate variable and reheating on semi-solid structure of ductile cast iron

    Institute of Scientific and Technical Information of China (English)

    M. Nili-Ahmadabadi; F. Pahlevani; P. Babaghorbani

    2008-01-01

    Semi-solid metal casting and forming are known as a promising process for a wide range of metal alloys production. In spite of growing application of semi-solid processed light alloys, a few works have been reported about semi-solid processing of iron and steel. In this research inclined plate was used to change dendritic structure of iron to globular one. The effects of length and slope of plate on the casting structure were examined. The results show that the process can effectively change the dendritic structure to globular. In the slope plate angle of 7.5°and length of 560 mm with cooling rate of 67K·s-1 the optimum nodular graphite and solid globular particle were achieved.The results also show that by using slope plate inoculant fading can be prevented more easily since the total time of process is rather short.In addition, the semi-solid ductile cast iron prepared by inclined plate method, was reheated to examine the effect of reheating conditions on the microstructure and coarsening kinetics of the alloy. Solid fraction at different reheating temperatures and holding time was obtained and based on these results the optimum reheating temperature range was determined.

  6. The degradation processes in high loaded casts

    Directory of Open Access Journals (Sweden)

    E. Ďuriníková

    2010-01-01

    Full Text Available In this work are described structural changes of jet engine DV – 2 turbine blades and effect of degradation process. Turbine blades work in aggressively environs and because of that there are rate among high loaded cast stock. As an experimental material we have chose nickel superalloy ŽS6K with surface heat - resisting alitize layer. Evaluation is slant on largeness wearing over work of certain number of hour in operation. Effect working environs and overrun working temperatures is show changes measures as well as changes macrostructure of basic material blades. Evaluate is advance quantitative metallography through the medium metallographic software NIS element. Quantitative analysis evaluate thickness measures, quality control outer look and lack mixture in the seat, which is not splash, is precede by lack of near another applied protective layer. Allowance is knot on last examination in the area ratings protective heat-resisting layers and gives records for others possible ratings and experiments in this area.

  7. PLACE OF NUTRITION IN YOGA

    OpenAIRE

    Desai, B.P.

    1990-01-01

    Nutrition plays a very vital role in our life. Yoga and Ayurveda had laid down the foundations of dietetics. The valuable guidelines regarding various food articles and diet for Yoga Sadhaka, to achieve maximum benefits, are given in traditional yoga texts like Hatha Pradipika and Gheranda Samhitha. Now is the time to evaluate the place of nutrition in Yoga and to study how the dietetic principles in yoga will help to eradicate the national problem of Mal-nutrition and poverty which is the pr...

  8. Entire cast-in-place concrete lfoor (top) analysis of the causes and prevention of cracks in the system cover%混凝土整体现浇楼(顶)盖裂缝的成因分析和系统预防

    Institute of Scientific and Technical Information of China (English)

    徐智尧

    2015-01-01

    在房屋建筑工程中,混凝土整体现浇楼盖的使用非常广泛。但混凝土整体现浇楼盖裂缝往往会引起投诉、纠纷以及索赔要求等,因此裂缝是混凝土工程中普遍存在的问题,这就要求我们对此予以足够的重视。本文主要就混凝土整体现浇楼盖出现裂缝的原因以及进行系统预防的具体措施进行了分析研究。%In building engineering, concrete pouring the whole floor is widely used. But the entire cast-in-place concrete floor cracks often give rise to complaints, disputes and claims, so the concrete crack is a common problem in the engineering, which requires us to pay enough attention to. This paper mainly embodies the specific measures of pouring concrete whole floor cracks causes and prevention system is studied.

  9. Structural feature of cast Al-base composite

    Energy Technology Data Exchange (ETDEWEB)

    Ji, S.; Li, Y.; Wang, G.

    1986-02-01

    An observation was carried out on the features of microstructure, fracture, and worn surface of an Al-base composite prepared by rheocasting with graphite, SiC, and SiO/sub 2/. The alpha solid solution, Si, CuAl/sub 2/, and allied eutectics are found to nucleate and to grow up along the surface of particulates added during solidification of the compslurry. The short-range movement of the particulates may distribute more uniformly in matrix owing to rapidly raising temperature of the compslurry before casting. Over the particulate, a transition layer connects with the matrix, and the active element Mg accumulates more or less. Thus, a firm bond is joined between the particulate and matrix, and no more pores and cracks form on the microstructure of fractured or worn surface. 11 references.

  10. Micro precision casting based on investment casting for micro structures with high aspect ratio

    Institute of Scientific and Technical Information of China (English)

    YANG Chuang; LI Bang-sheng; REN Ming-xing; FU Heng-zhi

    2009-01-01

    Microcasting is one of the significant technologies for the production of metallic micro parts with high aspect ratio (ratio of flow length to diameter). A micro precision casting technology based on investment casting using centrifugal method was investigated. The micro parts of Zn-4%Al alloy with an aspect ratio up to 200 was produced at the centrifugal speed of 1 500 r/min and the mold temperature of 270 ℃. The investigations on the relationship between flow length and rotational speed were carried out. For microcasting, the flow length is not only dependent on the centrifugal speed under the constant centrifugal radius, but also on the preheating temperature of mold. The flow length increases as the rotational speed and the mold temperature increase, and is much higher at a mold temperature of 270 ℃ than at other mold temperatures.

  11. THE INFLUENCE OF THE INGOT MOLD COOLING ON THE STRUCTURE OF SILUMINA CASTINGS AK15M3 AT VERTICAL CENTRIFUGAL CASTING

    Directory of Open Access Journals (Sweden)

    V. Yu. Stecenko

    2013-01-01

    Full Text Available Influence of ways of the mold cooling on structure of castings with diameter of 135 mm from AK15M3 silumin at vertical centrifugal casting is investigated. It is established that for production of castings with diameter 135 mm from AK15M3 silumin with high mechanical and tribotechnical properties it is necessary to apply a shaped mould with water-spray cooling at expense of cooler of 0,42 m3/h.

  12. Revealing the microbial community structure of clogging materials in dewatering wells differing in physico-chemical parameters in an open-cast mining area.

    Science.gov (United States)

    Wang, Juanjuan; Sickinger, Maren; Ciobota, Valerian; Herrmann, Martina; Rasch, Helfried; Rösch, Petra; Popp, Jürgen; Küsel, Kirsten

    2014-10-15

    Iron rich deposits cause clogging the pumps and pipes of dewatering wells in open-cast mines, interfering with their function; however, little is known about either the microbial community structure or their potential role in the formation of these deposits. The microbial diversity and abundance of iron-oxidizing and -reducing bacteria were compared in pipe deposit samples with different levels of encrustation from 16 wells at three lignite mining sites. The groundwater varied in pH values from slightly acidic (4.5) to neutral (7.3), Fe(II) concentrations from 0.48 to 7.55 mM, oxygen content from 1.8 to 5.8 mg L(-1), and dissolved organic carbon (DOC) from 1.43 to 12.59 mg L(-1). There were high numbers of bacterial 16S rRNA gene copies in deposits, up to 2.5 × 10(10) copies g(-1) wet weight. Pyrosequencing analysis of bacterial 16S rRNA genes revealed that Proteobacteria was the most abundant phylum (63.3% of the total reads on average), followed by Actinobacteria (10.2%) and Chloroflexi (6.4%). Gallionella-related sequences dominated the bacterial community of pipe deposits and accounted for 48% of total sequence reads. Pipe deposits with amorphous ferrihydrite and schwertmannite mostly contained Gallionella (up to 1.51 × 10(10) 16S rRNA gene copies g(-1) wet weight), while more crystalline deposits showed a higher bacterial diversity. Surprisingly, the abundance of Gallionella was not correlated with groundwater pH, oxygen, or DOC content. Sideroxydans-related 16S rRNA gene copy numbers were one order of magnitude less than Gallionella, followed by acidophilic Ferrovum-related groups. Iron reducing bacteria were detected at rather low abundance, as was expected given the low iron reduction potential, although they could be stimulated by lactate amendment. The overall high abundance of Gallionella suggests that microbes may make major contributions to pipe deposit formation irrespective of the water geochemistry. Their iron oxidation activity might

  13. PLACE OF REFORMS IN WESTERN STRUCTURING PROCESS OF OTTOMAN STATE AND THEIR EFFECT ON MODERNIZATION(1718-1789

    Directory of Open Access Journals (Sweden)

    Zabit ACER

    2010-04-01

    Full Text Available When the crackle sounds started to be heard after the middle of the 17th century, that this wasn’t a temporary sound was understood. In order to understood the reason of these illnesses, old laws and sources were being examined and these were being told to the sultans and statesmen who could take the State to a traditional structure. The Ottoman State fell in luxury and dissipation in the pursuit of a tulip in the 18th century. In this peace term, the Ottomans knew Europeans very closely. The Ottoman State’s widening policy gave shape to its State structure and inner order. The Ottoman administrators sent ambassadors to Vienna and Paris after the Treaty of Passarowitz and wanted them to inform themselves not only about politics and diplomacy but also about social and cultural events and interesting things. Europe, which was examined by Ottoman Statesmen with a new eye, was living “Enlightenment Age”. It was understood that in reform studies made in the 18th century the Ottoman remained behind Europe. The effect of the West is clearly seen in these innovation studies. The effect of the West is clearly seen in these innovation studies. Although reforms studies were tried to be made in every area in this term, especially military area reforms were given importance. The Ottoman State stopped its widening policy across Europe and shaped its inner order and State structure.

  14. Establishment of mathematical moment model in twin casting rolling rolls

    Institute of Scientific and Technical Information of China (English)

    孙斌煜; 苑世剑; 张洪; 杜艳平; 张芳萍

    2002-01-01

    In continuous casting rolling process, the deformed body is different from the hot rolling strip. The metal in casting rolling zone is first assumed to be viscous fluid and the mathematical model of casting rolling force is established, then the calculating formula for casting rolling torque is derived. In addition, considering the effects of deforming cone and appendant torque of rotary junctions sealing ring, the calculating model which accords with casting rolling condition is found out. Theoretical formula is proved by experiment.

  15. Effects of ultrasonic treatment on structure of roll casting aluminum strip

    Institute of Scientific and Technical Information of China (English)

    MAO Da-heng; ZHANG Yun-fang; NIE Zhao-hui; LIU Qiao-hong; ZHONG Jue

    2007-01-01

    The experiment of ultrasonic treatment of roll casting aluminum strip on plane twin-roll cast-roller with double-heads ultrasonic tools was carried out, and the metallographic structure of the roll casting aluminum strip treated by ultrasonic was studied.The results show that ultrasonic treatment can refine the grain of the roll casting aluminum strips and make the structure of the strips more homogeneous. The effect is the best when the power of ultrasonic is 300 W and the incident angle of the guide rod is 45°. The mechanism of acoustic cavitations and acoustic flow on grain refinement was also discussed. The heat effect of intensity ultrasonic was studied. The present problems during ultrasonic roll casting process, such as the imperfect cooling system, the inaccurate calculation of ultrasonic energy, and the shape and position of the guide rod to be improved were pointed out.

  16. Undercooling and nodule count in thin walled ductile iron castings

    DEFF Research Database (Denmark)

    Pedersen, Karl Martin; Tiedje, Niels Skat

    2007-01-01

    Casting experiments have been performed with eutectic and hypereutectic castings with plate thicknesses from 2 to 8 mm involving both temperature measurements during solidification and microstructural examination afterwards. The nodule count was the same for the eutectic and hypereutectic castings...... in the thin plates (≤4.3 mm) while in the 8 mm plate the nodule count was higher in the hypereutectic than in the eutectic castings. The minimum temperature before the eutectic recalescence (Tmin) was 15 to 20ºC lower for the eutectic than for the hypereutectic castings. This is due to nucleation of graphite...... nodules which begins at a lower temperature in the eutectic than in the hypereutectic castings. The recalescence ∆Trec was however also larger for the eutectic casting and in the thin plates the maximum temperature after recalescence (Tmax) was the same in the eutectic and hypereutectic plates...

  17. Recent development of ductile cast iron production technology in China

    Institute of Scientific and Technical Information of China (English)

    Cai Qizhou; Wei Bokang

    2008-01-01

    Recent progress in the production and technology of ductile cast iron castings in China is reviewed.The manufacture and process control of as-cast ductile iron are discussed.The microstructure.properties and application of partial austenitization normalizing ductile iron and austempered duclile iron(ADI)are briefly depicted.The new development of duclile iron production techniques,such as cored-wire injection(wire-feeding nodularization)process,tundish cover ladle nodularizing process,horizontal continuous casting,and EPC process (lost foam)for ductile iron castings,etc.,are summarized.

  18. Recent development of ductile cast iron production technology in China

    Directory of Open Access Journals (Sweden)

    Cai Qizhou

    2008-05-01

    Full Text Available Recent progress in the production and technology of ductile cast iron castings in China is reviewed. The manufacture and process control of as-cast ductile iron are discussed. The microstructure, properties and application of partial austenitization normalizing ductile iron and austempered ductile iron (ADI are briefl y depicted. The new development of ductile iron production techniques, such as cored-wire injection (wire-feeding nodularization process, tundish cover ladle nodularizing process, horizontal continuous casting, and EPC process (lost foam for ductile iron castings, etc., are summarized.

  19. The lost foam process in pilot castings plattes

    Directory of Open Access Journals (Sweden)

    Z. Żółkiewicz

    2009-04-01

    Full Text Available The paper discusses the process of thermal evaporation of a foundry pattern. At several research-development centres, studies have beencarried out to examine the physico-chemical phenomena that take place in foundry mould filled with polystyrene pattern when it is pouredwith molten metal. In the technique of evaporative patterns, the process of mould filling with molten metal (the said mould holding inside a polystyrene pattern is interrelated with the process of thermal decomposition of this pattern. The process of polystyrene pattern evaporation in foundry mould under the effect of molten metal is of a very complex nature and depends on many different factors, still not fully investigated. The technology of evaporative patterns was used in manufacture of pilot castings of the high abrasion resistance plates. The material and the properties of the resultant castings were determined by the customer (patent protection. At the beginning of the studies, the properties of the pattern material were determined, patterns were assembled, the properties of the ceramic layer were determined as well as the technique of its preparation and application. The technique of molten metal feeding to the mould cavity was examined along with the parameters of the gating and feeding system, and casting cooling and solidification conditions (large contraction, shrinkage cavities and depressions.

  20. Effect of quenching temperature on structure and properties of centrifugal casting high speed steel roll

    Directory of Open Access Journals (Sweden)

    Fu Hanguang

    2009-02-01

    Full Text Available The critical points and time-temperature-transformation (TTT curves of the isothermal transformation diagrams for a high-speed steel casting on a horizontal centrifugal casting machine had been determined experimentally in the study. The effects of quenching temperature on the microstructures and properties of centrifugal casting high speed steel (HSS roll has been investigated using scanning electron microscopy (SEM, light optical microscopy (LOM and X-ray diffraction (XRD as well as using tensile, impact, and hardness tests. The results show that the HSS roll has excellent hardenability and its matrix structure can be transformed into the martensite after being quenched in the sodium silicate solution. The retained austenite in the quenching structure increases and the hardness decreases when the quenching temperature exceeds 1,040℃. The tensile strength and impact toughness of HSS roll increase once the quenching temperature is raised from 980℃ to 1,040℃. However, the tensile strength and impact toughness have no signifi cant change when the quenching temperature exceeds 1,040℃. The HSS roll quenched at 1,040℃ exhibits excellent comprehensive mechanical properties.

  1. Effect of quenching temperature on structure and properties of centrifugal casting high speed steel roll

    Institute of Scientific and Technical Information of China (English)

    Fu Hanguang; Cheng Xiaole; Du Zhongze; Lei Yingping; Feng Zhenjun

    2009-01-01

    The critical points and time-temperature-transformation (TTT) curves of the isothermal transformation diagrams for a high-speed steel casting on a horizontal centrifugal casting machine had been determined experimentally in the study. The effects of quenching temperature on the microstructures and properties of centrifugal casting high speed steel (HSS) roll has been investigated using scanning electron microscopy (SEM), light optical microscopy (LOM) and X-ray diffraction (XRD) as well as using tensile, impact, and hardness tests. The results show that the HSS roll has excellent hardenability and its matrix structure can be transformed into the martensite after being quenched in the sodium silicate solution. The retained austenite in the quenching structure increases and the hardness decreases when the quenching temperature exceeds 1,040℃. The tensile strength and impact toughness of HSS roll increase once the quenching temperature is raised from 980℃ to 1,040℃. However, the tensile strength and impact toughness have no significant change when the quenching temperature exceeds 1,040℃. The HSS roll quenched at 1,040℃ exhibits excellent comprehensive mechanical properties.

  2. CASTING OF DETAILS OF WEAR-RESISTANT CHROME CAST IRONS FOR CHROMIC MILLS IN COMBINED MOLDS AND CHILLS

    Directory of Open Access Journals (Sweden)

    K. E. Baranovskij

    2009-01-01

    Full Text Available Relative wear resistance of chrome cast irons of eutectic composition is determined in laboratory and industry conditions. Complex alloyed eutectic cast iron with increased wear resistance and mechanical characteristics is developed.

  3. Influence of Cast Iron Structure on the Glassmold Equipment Operational Defects

    Directory of Open Access Journals (Sweden)

    I. O. Leushin

    2015-01-01

    Full Text Available The growing demand for glass packaging contributes to the increase in production capacity of glass-container plants. Their equipment (cast iron glass-forming sets operates in continuous mode under complex cyclic thermal loads, which lead to the formation of operational defects on the working surfaces of details: graphite falling, cracks, oxidation, etc. Particular influence on the formation of these defects renders the microstructure of the material at the time of installation of details on the line.The article identifies the causes for formation of operational defects, formulates the ways to remedy them and prevent their occurrence.The authors studied details made from grey cast iron with flake and spherical forms of graphite. It is found that in the process of exploitation of the material is greatly reducing its hardness, strength, resistance to oxidation through of graphitization processes, chemical interaction of glass and iron, shock loads working edges. It is proved that the choice of initial microstructure of cast iron (the metal base, the graphite form, the presence of structural-free cementite exercises a determining influence on the durability of the mold tooling. The article proposes differential (layered arrangement of the graphite phase of cast iron in the alloy matrix (ferrite. This arrangement of high-carbon phase can simultaneously increase the thermal and oxidation resistance of the material. The formation of a layered structure of iron is produced by the intensification of the processes of alloying, modifying and directional freezing the melt.These data can be used to select the material of details by manufacturers glass-molds tooling.

  4. CHANGE OF CONNECTION BETWEEN MAGNETIC PARAMETERS OF CAST IRON IN COMPARISON WITH STEEL UNDER INFLUENCE OF INTERNAL DEMAGNETIZATION

    Directory of Open Access Journals (Sweden)

    S. G. Sandomirsky

    2014-01-01

    Full Text Available Connection of maximum magnetic permeability µm of cast irons with coercive force Нс and residual magnetism Мr is established in all size of changing of the magnetic characteristics of cast iron. Differences of this connection for steels and cast irons are revealed. Formula for calculation µm of steels by Нс and Мr is corrected for calculation µm of cast irons. As a result of correction the calculation error of cast irons µm is diminished. The results can be used in magnetic structural analysis instead of labor-consuming measurement µm.

  5. Preferential dissolution behaviour in Ni–Cr dental cast alloy

    Indian Academy of Sciences (India)

    Viswanathan S Saji; Han Cheol Choe

    2010-08-01

    A Ni–Cr–Mo dental alloy was fabricated by three different casting methods, viz. centrifugal casting, high frequency induction casting and vacuum pressure casting. The dependence of cast microstructure on the electrochemical corrosion behaviour was investigated using potentiodynamic cyclic and potentiostatic polarization techniques, impedance spectroscopy and scanning electron microscopy. The experimental results were compared and discussed with those obtained for a Co–Cr–Mo counterpart. The results of the study showed that the variation in casting morphologies with casting methods has only marginal influence in the overall corrosion resistance of Ni–Cr and Co–Cr dental alloys. There was severe preferential dissolution of Ni rich, Cr and Mo depleted zones from the Ni–Cr–Mo alloy. The overall corrosion resistance property of the Co–Cr base alloy was better than that of the Ni–Cr base alloy.

  6. Phase Transformation in Cast Superaustenitic Stainless Steels

    Energy Technology Data Exchange (ETDEWEB)

    Lee Phillips, Nathaniel Steven [Iowa State Univ., Ames, IA (United States)

    2006-01-01

    Superaustenitic stainless steels constitute a group of Fe-based alloys that are compositionally balanced to have a purely austenitic matrix and exhibit favorable pitting and crevice corrosion resistant properties and mechanical strength. However, intermetallic precipitates such as sigma and Laves can form during casting or exposure to high-temperature processing, which degrade the corrosion and mechanical properties of the material. The goal of this study was to accurately characterize the solid-solid phase transformations seen in cast superaustenitic stainless steels. Heat treatments were performed to understand the time and temperature ranges for intermetallic phase formations in alloys CN3MN and CK3MCuN. Microstructures were characterized using scanning electron microscopy (SEM), transmission electron microscopy (TEM), and energy and wavelength dispersive spectroscopy (EDS, WDS). The equilibrium microstructures, composed primarily of sigma and Laves within purely austenitic matrices, showed slow transformation kinetics. Factors that determine the extent of transformation, including diffusion, nucleation, and growth, are discussed.

  7. Solidification control in continuous casting of steel

    Indian Academy of Sciences (India)

    S Mazumdar; S K Ray

    2001-02-01

    An integrated understanding of heat transfer during solidification, friction/lubrication at solid-liquid interface, high temperature properties of the solidifying shell etc. is necessary to control the continuous casting process. The present paper elaborates upon the knowledge developed in the areas of initial shell formation, mode of mould oscillation, and lubrication mechanism. The effect of these issues on the caster productivity and the quality of the product has been discussed. The influence of steel chemistry on solidification dynamics, particularly with respect to mode of solidification and its consequence on strength and ductility of the solidifying shell, has been dealt with in detail. The application of these basic principles for casting of stainless steel slabs and processing to obtain good quality products have been covered.

  8. State of the Art Treatment of Non-Ferrous Castings 3-in-1 Heat Treatment Systems Combine Foundry Processes

    Institute of Scientific and Technical Information of China (English)

    Volker R. Knobloch

    2004-01-01

    The interior of a high-pressure die-casting is of an unsatisfactory quality. Engine blocks made with this die casting process show lower specific engine performance. Pressure die-casting can hardly be heat treated for obvious reasons.PSM (Precision Sand Molds) process uses sand and organic binder to generate a mold and even allows the manufacturing of complex diesel engine blocks in aluminum alloys. Combined technologies are available for semi-permanent mold castings with cores and castings made in Precision Sand Molds with organic binders. Castings are placed into the special heat treatment furnace immediately after pouring without the operations in stand alone machinery. This patented Sand Lion(R) 3-in-1 technology processes hot castings and carries out three (3) foundry processes simultaneously in one (1) automated machine: 1) De-coring and sand removal; 2) Thermal sand reclamation; 3) Solution heat treatment of castings. The combination of several main casting processes is reflected in significant reductions of energy consumption, of production costs, and improving the quality of the castings. Audits in foundries using the 3-in-1 process showed an average reduction in production costs of more than 30%.

  9. Casting of 3-dimensional footwear prints in snow with foam blocks.

    Science.gov (United States)

    Petraco, Nicholas; Sherman, Hal; Dumitra, Aurora; Roberts, Marcel

    2016-06-01

    Commercially available foam blocks are presented as an alternative material for the casting and preservation of 3-dimensional footwear impressions located in snow. The method generates highly detailed foam casts of questioned footwear impressions. These casts can be compared to the known outsole standards made from the suspects' footwear. Modification of the commercially available foam casting blocks is simple and fast. The foam block is removed and a piece of cardboard is secured to one side of the block with painter's masking tape. The prepared foam block is then placed back into its original box, marked appropriately, closed and stored until needed. When required the foam block is carefully removed from its storage box and gently placed, foam side down, over the questioned footwear impression. Next, the crime scene technician's hands are placed on top of the cardboard and pressure is gently applied by firmly pressing down onto the impression. The foam cast is removed, dried and placed back into its original container and sealed. The resulting 3D impressions can be directly compared to the outsole of known suspected item(s) of footwear.

  10. Influence of formwork surface on the orientation of steel fibres within self-compacting concrete and on the mechanical properties of cast structural elements

    DEFF Research Database (Denmark)

    Svec, Oldrich; Zirgulis, Giedrius; Bolander, John E.;

    2014-01-01

    The influences of formwork surface on the final orientation of steel fibres immersed in self-compacting concrete and on the resulting mechanical response of the cast structural elements are investigated. Experimental observations of fibre orientation within cast slabs, obtained via computed tomog...

  11. An adaptive view of caste differentiation in the neotropical wasp Polybia (Trichothorax) sericea Olivier (Hymenoptera: Vespidae).

    Science.gov (United States)

    Desuó, I C; Souza-Galheico, C B; Shima, S N; Santos, G M M; Cruz, J D; Bichara Filho, C C; Dias, C T S

    2011-01-01

    The tribe Epiponini comprehends the swarm-founding Neotropical wasps, with several species endemic to Brazil, which are extremely important in studies of social evolution of wasps. The Epiponini diverge in several ways from the definitions of high eusociality, since caste syndromes range from species without morphological caste differentiation to those with complete caste dimorphism, and all species are polygynous. Frequently, indirect studies based on morphometry and physiology are the only solutions to collect data regarding the natural history and caste system in this tribe, since most species are extremely aggressive and build enveloped nests, usually in places of difficult access. We analyzed morphological parameters in seven colonies of the Epiponini species Polybia (Trichothorax) sericea Olivier in different phases of colonial development. Nine body variables were taken and females were classified according to their ovary development and spermathecal contents. The results showed that caste differences in this species are based on a contrast among variables: queens have larger mesosoma and abdomen, but are smaller in head width and wing length. These results suggest that morphological caste differentiation in this species is based mainly on body shape. We considered this combination of characters as being adaptive. We also showed that caste differences varied according to the colony cycle, with more conspicuous differences when queen number is reduced.

  12. Die Soldering in Aluminium Die Casting

    Energy Technology Data Exchange (ETDEWEB)

    Han, Q.; Kenik, E.A.; Viswanathan, S.

    2000-03-15

    Two types of tests, dipping tests and dip-coating tests were carried out on small steel cylinders using pure aluminum and 380 alloy to investigate the mechanism of die soldering during aluminum die casting. Optical and scanning electron microscopy were used to study the morphology and composition of the phases formed during soldering. A soldering mechanism is postulated based on experimental observations. A soldering critical temperature is postulated at which iron begins to react with aluminum to form an aluminum-rich liquid phase and solid intermetallic compounds. When the temperature at the die surface is higher than this critical temperature, the aluminum-rich phase is liquid and joins the die with the casting during the subsequent solidification. The paper discusses the mechanism of soldering for the case of pure aluminum and 380 alloy casting in a steel mold, the factors that promote soldering, and the strength of the bond formed when soldering occurs. conditions, an aluminum-rich soldering layer may also form over the intermetallic layer. Although a significant amount of research has been conducted on the nature of these intermetallics, little is known about the conditions under which soldering occurs.

  13. Construction Technology of Cast-in-place Pile of Excavation Support under Complicated Geological Conditions%复杂地质条件下基坑支护灌注桩施工技术

    Institute of Scientific and Technical Information of China (English)

    许厚材

    2012-01-01

      There were various obstacles distributed in the miscellaneous fill in the site of Beijing Spring Garden project, such as old pipes, old foundation concrete, concrete blocks, the soil nails and steel strands of old foundation pit support, and there were also some pipelines near the piles need to be protected, the construction was very difficult.According to the engineering conditions,artificial hole-digging, drilling with long spiral drilling machine and post-insert reinforced cage were adopted in this project.The practice shows that these technologies can not only effectively deal with the shallow under-ground obstacles and protect the underground pipelines, but also has many advantages of simple and safe construction, high quality reliability and short construction period.The environment problems of slurry pollution and slurry treatment are com-pletely solved with obvious social and economic efficiency.The paper introduced these technologies about the construction process and operation points.%  北京政泉花园工程地质条件复杂,填土层中分布有各种旧管线、旧混凝土基础、混凝土块以及基坑支护留在土层中的土钉和钢绞线等地下障碍物,灌注桩附近有需要进行保护的管线,施工难度大。结合工程实际,采用人工挖孔、长螺旋钻孔后插钢筋笼施工技术。实践表明,该施工工艺能够有效处理浅层地下障碍物和保护地下管线,同时具有施工简单、安全、质量可靠性高,缩短工期等优点,并从根本上排除了泥浆污染和泥浆处理等环保问题,具有明显的经济效益与社会效益。介绍了该施工技术的施工工艺流程、操作要点。

  14. Directional migration in the Hindu castes: inferences from mitochondrial, autosomal and Y-chromosomal data.

    Science.gov (United States)

    Wooding, Stephen; Ostler, Christopher; Prasad, B V Ravi; Watkins, W Scott; Sung, Sandy; Bamshad, Mike; Jorde, Lynn B

    2004-08-01

    Genetic, ethnographic, and historical evidence suggests that the Hindu castes have been highly endogamous for several thousand years and that, when movement between castes does occur, it typically consists of females joining castes of higher social status. However, little is known about migration rates in these populations or the extent to which migration occurs between caste groups of low, middle, and high social status. To investigate these aspects of migration, we analyzed the largest collection of genetic markers collected to date in Hindu caste populations. These data included 45 newly typed autosomal short tandem repeat polymorphisms (STRPs), 411 bp of mitochondrial DNA sequence, and 43 Y-chromosomal single-nucleotide polymorphisms that were assayed in more than 200 individuals of known caste status sampled in Andrah Pradesh, in South India. Application of recently developed likelihood-based analyses to this dataset enabled us to obtain genetically derived estimates of intercaste migration rates. STRPs indicated migration rates of 1-2% per generation between high-, middle-, and low-status caste groups. We also found support for the hypothesis that rates of gene flow differ between maternally and paternally inherited genes. Migration rates were substantially higher in maternally than in paternally inherited markers. In addition, while prevailing patterns of migration involved movement between castes of similar rank, paternally inherited markers in the low-status castes were most likely to move into high-status castes. Our findings support earlier evidence that the caste system has been a significant, long-term source of population structuring in South Indian Hindu populations, and that patterns of migration differ between males and females.

  15. Transparent layered YAG ceramics with structured Yb doping produced via tape casting

    Science.gov (United States)

    Hostaša, Jan; Piancastelli, Andreana; Toci, Guido; Vannini, Matteo; Biasini, Valentina

    2017-03-01

    The flexibility of the ceramic production process, in particular in terms of shaping and spatial control of distribution of active ions, is one of the strong points in favor of transparent ceramics. In high power lasers in particular, where thermal management is a critical issue, the finely controlled design of spatial distribution of the doping ions within the laser gain media can reduce undesired thermally induced effects and large temperature gradients, and thus enhance the efficiency and laser beam quality especially under increased thermal load. In the present work transparent structured YAG ceramics with Yb doping were produced by tape casting followed by thermal compression of assembled tapes and sintered under high vacuum. The thermal compression of variously doped tape cast layers is a very promising method because it allows a high precision and good control over dopant distribution in the sintered material. After sintering, the distribution of Yb across the layers was characterized by SEM-EDX and the thickness of Yb diffusion zones between the layers with different Yb content was measured. Optical homogeneity was assessed by means of optical transmittance mapping of the samples and by 2D scanning of laser output. The effect of structured dopant distribution on laser performance was measured in quasi-CW and CW regime with different duty factors. Slope efficiency values higher than 50% were measured both in quasi-CW and in CW lasing conditions. The results are in good agreement with previously calculated predictions, confirming the beneficial effect of structured doping on laser performances and enlightening the impact of the residual scattering losses. Compared to other processing methods, such as the pressing of granulated powders, tape casting followed by thermal compression leads to straight and narrow interfaces between layers with different composition and allows to build structures composed of extremely thin layers with defined dopant content.

  16. Semi-solid thixo casting structure of aluminum alloy and relevant assistant analysis with the help of computer simulation

    Institute of Scientific and Technical Information of China (English)

    Yi-tao YANG; Jian-fu WANG; Meng CHEN; Heng-hua ZHANG; Guang-jie SHAO

    2008-01-01

    The relationship between structure morphology of semi-solid aluminum alloy die-casting sample and filling condition was studied. By systematical structure analysis and computer simulation of the filling process, the quant-itative relationship between microscopic morphology (such as solid fraction, grain size and shape) and formation state was studied. The results showed that the billet microstruc-ture must have fine and round grains for the die-casting of complex shapes. It is necessary to optimize injection speeds to escape the non-uniform distribution of the solid fraction in complex and changeable mold cavity.

  17. The food choice kaleidoscope. A framework for structured description of product, place and person as sources of variation in food choices.

    Science.gov (United States)

    Jaeger, Sara R; Bava, Christina M; Worch, Thierry; Dawson, John; Marshall, David W

    2011-04-01

    Despite a wide range of research approaches already being used to study eating and drinking, this complex aspect of human activity lacks conceptualisation and methodology for structured description of food choices. This paper introduces a metaphoric framework--the food choice kaleidoscope--as an approach to such inquiry. It conceptualises individual food choice events (or eating occasions) as being shaped by three main factors--product, person and place--and provides a descriptive approach through which patterns and variability in food choice events can be observed. The factors can be studied separately or in combination to reveal the joint influence of product, place and/or person factors. The approach is 'data hungry' and requires information about large numbers of eating occasions obtained for a variety of foods/beverage in a variety of situations. Using information about ∼5800 eating occasions obtained from 25 New Zealand women who self-completed 24-h recall diaries, the kaleidoscopic approach is illustrated. The data are analysed in relation to 30 food/beverage categories and 37 contextual (or 'place') variables, and at the level of individual participants. Results are presented that document: product-to-product variability in who eats/drinks what and where/how it is consumed; place-to-place variation in what is consumed and by whom; and person-to-person variability in what is consumed and where/how it is consumed. The most significant insight to emerge is the considerable heterogeneity that is hidden beneath the average patterns, and that average values may be inappropriate/irrelevant for this type of data.

  18. CENTRIFUGAL CASTING MACHINE

    Science.gov (United States)

    Shuck, A.B.

    1958-04-01

    A device is described that is specifically designed to cast uraniumn fuel rods in a vacuunn, in order to obtain flawless, nonoxidized castings which subsequently require a maximum of machining or wastage of the expensive processed material. A chamber surrounded with heating elements is connected to the molds, and the entire apparatus is housed in an airtight container. A charge of uranium is placed in the chamber, heated, then is allowed to flow into the molds While being rotated. Water circulating through passages in the molds chills the casting to form a fine grained fuel rod in nearly finished form.

  19. High integrity automotive castings

    Energy Technology Data Exchange (ETDEWEB)

    Weiss, D. [Eck Industries Inc., St. Manitowoc, WI (United States)

    2007-07-01

    This paper described the High Integrity Magnesium Automotive Casting (HI-MAC) program, which was developed to ensure the widespread adoption of magnesium in structural castings. The program will encourage the use of low pressure permanent molds, squeeze casting, and electromagnetic pumping of magnesium into dies. The HI-MAC program is currently investigating new heat treatment methods, and is in the process of creating improved fluid flow and solidification modelling to produce high volume automotive components. In order to address key technology barriers, the program has been divided into 8 tasks: (1) squeeze casting process development; (2) low pressure casting technology; (3) thermal treatment; (4) microstructure control; (5) computer modelling and properties; (6) controlled molten metal transfer and filling; (7) emerging casting technologies; and (8) technology transfer throughout the automotive value chain. Technical challenges were outlined for each of the tasks. 1 ref., 3 tabs., 5 figs.

  20. Infant Perception of Incongruent Shapes in Cast Shadows

    Directory of Open Access Journals (Sweden)

    Kazuki Sato

    2015-04-01

    Full Text Available A cast shadow occurs when an object blocks the light from an illumination and projects a dark region onto a surface. Previous studies have reported that adults are slower to identify an object when the object has an incongruent cast shadow than when it has a congruent cast shadow (Castiello, 2001. Here, we used the familiarization-novelty preference procedure to examine whether 5- to 8-month-old infants could detect the relationship between object shapes and cast shadows. In Experiment 1, we examined the infants' ability to detect incongruency between objects and cast shadows. Results showed that 7- to 8-month olds could detect incongruence between the object shapes and the cast shadows, whereas 5- to 6-month olds did not. Yet, our control experiment showed that infants could not detect this incongruence from stimuli in which a white outline had been added to the original cast shadow to decrease the possibility of it being perceived as a cast shadow (Experiment 2. The results of these experiments demonstrate that 7- to 8-month olds responded to the congruence of cast shadows and to consistent contrast polarity between the cast shadow and its background.

  1. Modelling of fluid flow in tape casting of thin ceramics: Analytical approaches and numerical investigations

    DEFF Research Database (Denmark)

    Jabbaribehnam, Mirmasoud; Hattel, Jesper Henri

    2016-01-01

    components are dependent upon tape casting technology. One of the growing sciences in the processing of ceramics by tape casting is the use of fluid flow analysis to control and enhance the final tapes. The fluid dynamics analysis of the ceramic slurries during tape casting is an efficient mean to elucidate......Tape casting has been used to produce thin layers of ceramics that can be used as single layers or can be stacked and laminated into multilayered structures. Many startup products such as multilayered inductors, multilayered varistors, piezoelectrics, ceramic fuel cells and lithium ion battery...... the physical parameters crucial to the process. A review of the development of the tape casting process with particular focus on modelling the material flow is presented and in this context the current status is examined and future potential discussed....

  2. The Structure and Properties of Inductively Coupled Plasma Assisted Magnetron Sputtered Nanocrystalline NbN Coatings in Corrosion Protective Die Casting Molds.

    Science.gov (United States)

    Chun, Sung-Yong

    2016-02-01

    Niobium nitride coatings for the surface modified die casting molds with various ICP powers have been prepared using ICP assisted magnetron sputtering. The applied ICP power was varied from 0 to 200 W. The deposited coatings were characterized post-deposition using X-ray diffractometry (XRD) and atomic force microscopy (AFM). Single NbN phased coatings with nano-grain sized (hardness of each coating were evaluated from potentiostat and nanoindentator. Superior corrosion protective coatings in excess of 13.9 GPa were deposited with assistance of ICP plasma during sputtering.

  3. Comparison of residual stresses in sand- and chill casting of ductile cast iron wind turbine main shafts

    DEFF Research Database (Denmark)

    Sonne, Mads Rostgaard; Frandsen, J. O.; Hattel, Jesper Henri

    2015-01-01

    In this work, simulations of pouring, solidification and cooling, and residual stress evolution of sand and chill cast wind turbine main shafts is performed. The models are made in the commercial software MAGMAsoft. As expected, the cooling rate of the sand casting is shown to be much lower than...... for the chill casting, resulting in a very course microstructure.From the simulations the nodule count is found to be 17 nodules per mm2 and 159 nodules permm2 for the sand and chill casting, respectively, in the critical region of the main bearing seat.This is verified from nodule counts performed on the real...... cast main shafts. Residual stressevaluations show an overall increase of the maximum principal stress field for the chill casting,which is expected. However, the stresses are found to be in compression on the surface of thechill cast main shaft, which is unforeseen....

  4. The history and present of art casting in China

    Institute of Scientific and Technical Information of China (English)

    2004-01-01

    @@ A compendiary review of art casting in China: History of art casting in china has been over 5000 years. In the past few thousand years, numerous forming and decorating skills of art castings had been created, and left behind precious treasures in the world metal arts and crafts. In individual historical period and at different terrain, a unique artistic style formed,which flashed brilliant light in world artistic treasury.

  5. Dynamic control of crystallinity in polymer film casting process

    OpenAIRE

    Thananchai Leephakpreeda

    2005-01-01

    This paper presents an approach for dynamic control of crystallinity in polymer film casting process. As known, the transients of crystallization dictate the microstructures of semi-crystalline polymer during solidification. In turn, the properties of finished products can be determined by adjustable variables in polymer film casting process such as temperature of chill roll. In this work, an experimental model of the solidification in film casting process is derived by a system identificatio...

  6. LIGHT-WEIGHT LOAD-BEARING STRUCTURES REINFORCED BY CORE ELEMENTS MADE OF SEGMENTS AND A METHOD OF CASTING SUCH STRUCTURES

    DEFF Research Database (Denmark)

    2009-01-01

    The invention relates to a light-weight load-bearing structure, reinforced by core elements (2) of a strong material constituting one or more compression or tension zones in the structure to be cast, which core (2) is surrounded by or adjacent to a material of less strength compared to the core (2......), where the core (2) is constructed from segments (1) of core elements (2) assembled by means of one or more prestressing elements (4). The invention further relates to a method of casting of light-weight load-bearing structures, reinforced by core elements (2) of a strong material constituting one...... or more compression or tension zones in the structure to be cast, which core (2) is surrounded by or adjacent to a material of less strength compared to the core (2), where the core (2) is constructed from segments (1) of core elements (2) assembled and hold together by means of one or more prestressing...

  7. 均匀黏弹性地基中现浇 X 形桩低应变动测响应数值模拟%Numerical Simulation of Low Strain Dynamic Test Response for X-section Cast-in-place Concrete Pile on Homogeneous Viscoelastic Foundation

    Institute of Scientific and Technical Information of China (English)

    范玉明; 丁选明; 朱振生; 付强

    2015-01-01

    A three dimensional finite model of an X-section cast-in-place concrete pile-soil system is established to simulate wave propagation in a low strain integrity X-section cast-in-place concrete pile (XCC pile).Velocity responses in the time domain at the top of the intact and defective piles are obtained.The velocity response characteristics of the intact pile are analyzed in addition to the velocity response curves of the defective piles.The results reveal that the velocity response at the top of the XCC pile during low strain integrity testing shows serious 3D effects,resulting in the peak value of the incident wave close to the pile center being largest,and the arrival time of the peak value of the incident wave close to the pile center being earliest.The farther a point is from the pile center,the more hysteretic is the peak of the arriving incident wave.The peak value of the incident waves first increases and then reduces from the pile center to the pile boundary.The inci-dent and reflected waves at different points along the ring direction at the top of the intact pile are very similar,but the disturbing waves of different points are not the same.The arrival time of the incident waves in the pile with variable modulus are the same as those in the intact pile,but the arrival time of the peak of the reflection wave at the bottom of the pile with variable modulus is later than that in the intact pile,and the peak value is smaller.The first defective reflected waves at different points along ring direction at the top of the defective XCC pile shows little differ-ences,but the second one shows larger differences.%建立现浇 X 形桩(XCC 桩)桩-土体系三维有限元模型,对 XCC 桩低应变检测动力响应进行数值模拟,得到完整桩和缺陷桩的桩顶速度响应结果,并分析完整桩及缺陷 XCC 桩桩顶速度响应特性及规律。计算结果表明:XCC 桩低应变瞬态动测时桩顶速度响应存在明显的三维效应,桩

  8. Communication in the Third Places

    Institute of Scientific and Technical Information of China (English)

    贾俊民; 薛小梅

    2002-01-01

    The paper aims to have a tentative study of Kramsch's intercultural approach in relation to the other approaches in the field. It holds that Kramsch's approach is successful in making a reliable and authentic description of the real situation in intercultural communication. That is, intercultural communication occurs in the so-called third places, neither in home cultural context nor in target cultural context. Based on this understanding, the approach emphasizes the authenticity of culture and its dynamic nature. Then the paper focuses on the pedagogical implications this approach suggests and holds that it helps us to avoid two aberrant directions in foreign language teaching with regard to Chinese situation: cultural nativization and cultural hegemony. Finally, the paper points out that Kramsch's approach is, on the whole, sound in theory, but it is a long way to go before putting it into teaching practice due to the absence of sufficient data support and the complexity of language learning.%对以 Kramsch 为代表的跨文化交际研究思路与该领域其他研究思路进行对比探索性研究.笔者认为 Kramsch 的研究非常成功地描述了真实情景下跨文化交际的模式,也就是说,跨文化交际发生在所谓的第三位置,既不在本族语文化情境环境中,又不在目标语文化情境环境中.根据这一理解, Kramsch 的研究思路强调文化的真实性及其动态特性.这一研究思路在中国外语教学环境下,可帮助我们避免在外语教学中走极端.即完全文化融入或文化霸权. Kramsch 的理论总体上来说是无懈可击的,但由于还缺乏足够的数据资料支持以及语言学习过程的复杂性,因而要将其理论付诸语言教学实践,还有很长的路要走.

  9. Effect of casting methods on the structure and properties of tin babbit

    Science.gov (United States)

    Potekhin, B. A.; Il'yushin, V. V.; Khristolyubov, A. S.

    2009-07-01

    Dependence of the properties of babbit of grade B83 on the structure formed due to different methods of casting is determined. A novel advanced method of centrifugal casting of babbit B83 is suggested, which ensures crystallization of SnSb and Cu3Sn intermetallics from a turbulently moving melt. This not only removes segregation but also transfers the acute-angle SnSb intermetallic into a globular form.

  10. Recent development of ductile cast iron production technology in China

    OpenAIRE

    Cai Qizhou; Wei Bokang

    2008-01-01

    Recent progress in the production and technology of ductile cast iron castings in China is reviewed. The manufacture and process control of as-cast ductile iron are discussed. The microstructure, properties and application of partial austenitization normalizing ductile iron and austempered ductile iron (ADI) are briefl y depicted. The new development of ductile iron production techniques, such as cored-wire injection (wire-feeding nodularization) process, tundish cover ladle nodularizing proc...

  11. Phase Transformations in Cast Duplex Stainless Steels

    Energy Technology Data Exchange (ETDEWEB)

    Yoon-Jun Kim

    2004-12-19

    Duplex stainless steels (DSS) constitute both ferrite and austenite as a matrix. Such a microstructure confers a high corrosion resistance with favorable mechanical properties. However, intermetallic phases such as {sigma} and {chi} can also form during casting or high-temperature processing and can degrade the properties of the DSS. This research was initiated to develop time-temperature-transformation (TTT) and continuous-cooling-transformation (CCT) diagrams of two types of cast duplex stainless steels, CD3MN (Fe-22Cr-5Ni-Mo-N) and CD3MWCuN (Fe-25Cr-7Ni-Mo-W-Cu-N), in order to understand the time and temperature ranges for intermetallic phase formation. The alloys were heat treated isothermally or under controlled cooling conditions and then characterized using conventional metallographic methods that included tint etching, and also using electron microscopy (SEM, TEM) and wavelength dispersive spectroscopy (WDS). The kinetics of intermetallic-phase ({sigma} + {chi}) formation were analyzed using the Johnson-Mehl-Avrami (MA) equation in the case of isothermal transformations and a modified form of this equation in the case of continuous cooling transformations. The rate of intermetallic-phase formation was found to be much faster in CD3MWCuN than CD3MN due mainly to differences in the major alloying contents such as Cr, Ni and Mo. To examine in more detail the effects of these elements of the phase stabilities; a series of eight steel castings was designed with the Cr, Ni and Mo contents systematically varied with respect to the nominal composition of CD3MN. The effects of varying the contents of alloying additions on the formation of intermetallic phases were also studied computationally using the commercial thermodynamic software package, Thermo-Calc. In general, {sigma} was stabilized with increasing Cr addition and {chi} by increasing Mo addition. However, a delicate balance among Ni and other minor elements such as N and Si also exists. Phase equilibria in

  12. Phase Transformations in Cast Duplex Stainless Steels

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Yoon-Jun [Iowa State Univ., Ames, IA (United States)

    2004-01-01

    Duplex stainless steels (DSS) constitute both ferrite and austenite as a matrix. Such a microstructure confers a high corrosion resistance with favorable mechanical properties. However, intermetallic phases such as σ and χ can also form during casting or high-temperature processing and can degrade the properties of the DSS. This research was initiated to develop time-temperature-transformation (TTT) and continuous-cooling-transformation (CCT) diagrams of two types of cast duplex stainless steels, CD3MN (Fe-22Cr-5Ni-Mo-N) and CD3MWCuN (Fe-25Cr-7Ni-Mo-W-Cu-N), in order to understand the time and temperature ranges for intermetallic phase formation. The alloys were heat treated isothermally or under controlled cooling conditions and then characterized using conventional metallographic methods that included tint etching, and also using electron microscopy (SEM, TEM) and wavelength dispersive spectroscopy (WDS). The kinetics of intermetallic-phase (σ + χ) formation were analyzed using the Johnson-Mehl-Avrami (MA) equation in the case of isothermal transformations and a modified form of this equation in the case of continuous cooling transformations. The rate of intermetallic-phase formation was found to be much faster in CD3MWCuN than CD3MN due mainly to differences in the major alloying contents such as Cr, Ni and Mo. To examine in more detail the effects of these elements of the phase stabilities; a series of eight steel castings was designed with the Cr, Ni and Mo contents systematically varied with respect to the nominal composition of CD3MN. The effects of varying the contents of alloying additions on the formation of intermetallic phases were also studied computationally using the commercial thermodynamic software package, Thermo-Calc. In general, σ was stabilized with increasing Cr addition and χ by increasing Mo addition. However, a delicate balance among Ni and other minor elements such as N and Si also exists. Phase equilibria in DSS can be affected by

  13. Fabrication of in situ composite layer on cast steel

    Directory of Open Access Journals (Sweden)

    E. Fraś

    2010-01-01

    Full Text Available The study describes the technology of fabrication of composite layers in cast steel reinforced with titanium carbides. In the process under discussion, the reinforcing TiC phase is formed in situ from the substrates deposited on mould cavity, where the said substrates under the effect of heat supplied by molten metal poured into mould (1823K undergo a synthesis in the SHS reaction. An outcome of this process is the formation, within the casting surface, of a layer from 550 to 1200μm thick. Carbides produced in this synthesis have the size from 0,5 to 20μm and a non-typical spheroidal shape. The hardness of the produced layer examined in function of the distance from the casting surface is from 700 to 1134 HV, and is determined by volume fraction of the reinforcing TiC phase. To better document the type of microstructure obtained in the produced material, metallographic and structural examinations were carried out using the method of scanning electron microscopy (SEM, X-ray microanalysis (EDS/EDX, and phase analysis (XRD. To check the mechanical properties of the examined material, hardness was measured by the Vickers test.

  14. Multi-Material and Thickness Optimization Utilizing Casting Filters for Laminated Composite Structures

    DEFF Research Database (Denmark)

    Sørensen, Rene; Lund, Erik

    2013-01-01

    This extended abstract presents a new parameterization for performing discrete material and thickness optimization of laminated composite structures. The parameterization is based on the work by Sørensen and Lund 2013, where we present a reformulation of the original parameterization....... The reformulation eliminates the need for having explicit constraint for ensuring that intermediate void does not appear in between layers of the laminate. This is achieved by utilizing a filtering technique known as a casting constraint from traditional topology optimization with isotropic materials....

  15. Characterization of Casting Defects in Typical Castings of a Directionally Solidified Superalloy

    Science.gov (United States)

    1979-08-01

    used to evaluate grain misorientation effects in D.S. MAR - M247 superalloy (17). Scatter of this nature has been observed previously in equiaxed cast...found associated with the fracture surfaces In the previous study on tje effect of off-axis grain growth on cylindrical cast bars of D.S. MAR - M247 , 1800...significant that no instances of failures associated with emergent grains were observed in the MAR - M247 study. In the present investigation of PWA 1422, no

  16. Influence of electromagnetic field parameters on the morphology of graphite in grey cast iron

    Directory of Open Access Journals (Sweden)

    J. Szajnar

    2009-01-01

    Full Text Available One way to improve the unification of the casting structure may be the application of forced convection of liquid metal during thecrystallization in the form or continuous casting mould. This paper presents the results describing the influence of selected parameters of rotating electromagnetic field enforcing the movement of liquid metal in the form on the morphology of graphite in grey cast iron. The results were fragmented graphite flakes in conditions of regulating the rate of cooling in the range of temperature TZAL

  17. Thermal analysis of ductile iron in thin walled casting

    Directory of Open Access Journals (Sweden)

    M. Górny

    2007-12-01

    Full Text Available Hypereutectic ductile iron was cast in self hardening moulding sand to produce castings with the shape of Archimedes spirals and with wall thickness of 1, 2 and 3 mm. Inmould technique was used to produce thin wall ductile iron (TWDI. In this work it has been carried out thermal analysis in spiral with 3 mm wall thickness. The present work provides results of thermal analysis, that are initial temperature of metal in mould cavity, velocity of metal stream as well as solidification time. Measurement of temperature shows that there is essential its drop during filling of mould cavity and amounts 230 oC for distance 700 mm from the beginning of spiral. On the basic on first derivative of temperature versus time characteristic solidification points were distinguish, namely solidification of primary graphite, austenite dendrite and eutectic. Experimental measurements of temperature drop during filling of mould cavity along with microscopic examinations of castings structure can be used to verify computer modeling and simulation of fluid flow and thermal field in TWDI.

  18. Dataset on outdoor behavior-system and spatial-pattern in the third place in cold area-based on the perspective of new energy structure.

    Science.gov (United States)

    Ren, Kai; Wang, Yuan; Liu, Tingxi; Wang, Guanli

    2017-02-01

    The data presented in this paper are related to the research article entitled "Exploration of Outdoor Behavior System and Spatial Pattern in the Third Place in Cold Area- based on the perspective of new energy structure" (Ren, 2016) [1]. The dataset was from a field sub-time extended investigation to residents of Power Home Community in Inner Mongolia of China that belongs to cold region of ID area according to Chinese design code for buildings. This filed data provided descriptive statistics about environment-behavior symbiosis system, environment loading, behavior system, spatial demanding and spatial pattern for all kinds of residents (Older, younger, children). The field data set is made publicly available to enable critical or extended analyzes.

  19. The structures of flux-cast refractories in the Cr/sub 2/O/sub 3/-Al/sub 2/O/sub 3/-ZrO/sub 2/-SiO/sub 2/ system

    Energy Technology Data Exchange (ETDEWEB)

    Popov, O.N.; Frolova, V.P.

    1985-08-01

    The authors examine the mineral formation and structural features in slip-cast refractories in the Cr/sub 2/O/sub 3/-Al/sub 2/O /SUB J/ -ZrO/sub 2/-SiO/sub 2/ system by x-ray, petrographic, and microprobe methods, and they analyze the data gathered to formulate a scheme for the crystallization. A table contains figures on the chemical and mineral composition of chromium-aluminum-zirconium refractories; microphotographs reveal the microstructures in the system; and a chart presents distribution curves for Cr, Al, Zr, and Si in the refractory in solid solution, vitreous phase, and baddeleyite.

  20. Development,Application and Problem of Ductile Iron Lost Foam Casting Technology in China

    Institute of Scientific and Technical Information of China (English)

    He Wenhao; Ye Shengping; Han Xiaohong; Tang Suoyun

    2010-01-01

    @@ Lost-foam casting is a 21st century green casting technology.Over the past decade,there has been an extraordinary development in lost-foam casting in China;and ductile iron lost-foam casting has developed even more rapidly in foundry equipment,foundry raw materials,and casting engineers.

  1. Effect of the concentrated heat flow treatment on the structure and the antiwear properties of cast iron

    Directory of Open Access Journals (Sweden)

    W. Orlowicz

    2009-04-01

    Full Text Available The influence of modes of surface fusion by electric arc plasma (GTAW method on the hardness and wear-resistance of plain cast ironwas studied. A possible mechanism of structural rearrangement in the processed material during the friction was analyzed. This mechanismis determined by specific behaviour of hardened martensitic structure under dynamic load. This martensitic structure forms a metalbasis of cementite eutectic under conditions of fast crystallisation.

  2. mtDNA variation in caste populations of Andhra Pradesh, India.

    Science.gov (United States)

    Bamshad, M; Fraley, A E; Crawford, M H; Cann, R L; Busi, B R; Naidu, J M; Jorde, L B

    1996-02-01

    Various anthropological analyses have documented extensive regional variation among populations on the subcontinent of India using morphological, protein, blood group, and nuclear DNA polymorphisms. These patterns are the product of complex population structure (genetic drift, gene flow) and a population history noted for numerous branching events. As a result, the interpretation of relationships among caste populations of South India and between Indians and continental populations remains controversial. The Hindu caste system is a general model of genetic differentiation among endogamous populations stratified by social forces (e.g., religion and occupation). The mitochondrial DNA (mtDNA) molecule has unique properties that facilitate the exploration of population structure. We analyzed 36 Hindu men born in Andhra Pradesh who were unrelated matrilineally through at least 3 generations and who represent 4 caste populations: Brahmin (9), Yadava (10), Kapu (7), and Relli (10). Individuals from Africa (36), Asia (36), and Europe (36) were sampled for comparison. A 200-base-pair segment of hypervariable segment 2 (HVS2) of the mtDNA control region was sequenced in all individuals. In the Indian castes 25 distinct haplotypes are identified. Aside from the Cambridge reference sequence, only two haplotypes are shared between caste populations. Middle castes form a highly supported cluster in a neighbor-joining network. Mean nucleotide diversity within each caste is 0.015, 0.012, 0.011, and 0.012 for the Brahmin, Yadava, Kapu, and Relli, respectively. mtDNA variation is highly structured between castes (GST = 0.17; p caste populations of Andhra Pradesh cluster more often with Africans than with Asians or Europeans. This is suggestive of admixture with African populations.

  3. Role of the preliminary heat treatment in anisothermic eutectoid change of the cast iron

    Directory of Open Access Journals (Sweden)

    T. Szykowny

    2011-07-01

    Full Text Available Preliminary heat treatment, preceding continuous cooling of the iron casting, assumed in the research, complies with the applied in prac- tice single normalization, double normalization or normalization with slow cooling. In each of these cases continuous cast iron cooling has been begun from the same temperature 925°C. CCT diagrams have been made with use of metallographic method. The mechanism, kinet- ics and the final structure of eutectoid change of the cast iron after such treatment have been traced.

  4. Structure homogeneity as a parameter for evaluation of composite casting quality

    Directory of Open Access Journals (Sweden)

    K. Gawdzińska

    2010-07-01

    Full Text Available The structure of composite materials is be usually described as a compound of two structural components called matrix and reinforcement,respectively. A classic, commonly known example is polyester resin reinforced with glass fibres. Composite materials obtained throughcasting techniques are frequently characterised by irregular distribution and content of reinforcement in the casting volume as well as by different shape and size of this structural element [1–5]. It clearly results from the fundamentals of materials engineering that this type of structural diversity has a crucial effect on its broadly understood properties. Therefore, a need arises to define in a simple but precise way what we understand as homogeneity or non-homogeneity of the material, as well as for introduction of measures for this feature. The present study is limited to cast metal-matrix composite materials that, due to their manufacture technology, are particularly susceptible to the occurrence of non-homogeneity. However, the proposed solution may be also applied in characterisation of other materials. Till now, the concept of non-homogeneity has no commonly accepted definition [6-10]. Among others, it is defined as: – deviation of certain geometric features from the structure accepted conventionally as homogenous;– local structure disorder, the intensity of which is accomplished with different probability; – derivative of the diversity of geometric features of measured elements which results from their orientation (anisotropy or position (gradient in a tested object.In the case of composite castings when the concept of defect as deviation from the desired features is being used as a rule in describing the quality parameters of these materials, it seems to be advisable to introduce the concept of material homogeneity. Deviation from this feature, i.e. a defect, will be the non-homogeneity of, for instance, structure porosity or amount, spatial distribution, size

  5. Prediction of Microstructure in ADI Castings

    Directory of Open Access Journals (Sweden)

    Guzik E.

    2016-12-01

    Full Text Available Tests were carried out on samples of low-alloy ductile iron with additions of Ni, Cu and Mo, subjected to austempering heat treatment. The samples were austenitized at 850, 900 and 950 °C, and then austempered at T = 210, 240, 270, 300 and 330 °C. The ausferritizing treatment was carried out in a salt bath for the time τ = 2 - 8 hours. Additionally, tests and studies covered samples subjected to the ausferritizing treatment at 270 °C with the time of holding castings in a bath from 2 to 24 hours. Evaluation covered the results of the ADI microstructure examinations and hardness measurements. The ADI matrix morphology was identified counting the average number of ausferrite plates and measuring their width and spacing. The regression equations HB = f (τ, T and τ = f (HB, T were derived to establish the, so-called, “process window”, allowing obtaining a priori the required microstructure of ADI and, consequently, the required mechanical properties, mainly hardness, shaping the functional properties of castings, abrasion wear resistance – in particular.

  6. Self-assembly in casting solutions of block copolymer membranes

    KAUST Repository

    Marques, Debora S.

    2013-01-01

    Membranes with exceptional pore regularity and high porosity were obtained from block copolymer solutions. We demonstrate by small-angle X-ray scattering that the order which gives rise to the pore morphology is already incipient in the casting solution. Hexagonal order was confirmed in PS-b-P4VP 175k-b-65k solutions in DMF/THF/dioxane with concentrations as high as 24 wt%, while lamellar structures were obtained in more concentrated solutions in DMF or DMF/dioxane. The change in order has been understood with the support of dissipative particle dynamic modeling. © 2013 The Royal Society of Chemistry.

  7. Sense of Place in Environmental Education

    Science.gov (United States)

    Kudryavtsev, Alex; Stedman, Richard C.; Krasny, Marianne E.

    2012-01-01

    Although environmental education research has embraced the idea of sense of place, it has rarely taken into account environmental psychology-based sense of place literature whose theory and empirical studies can enhance related studies in the education context. This article contributes to research on sense of place in environmental education from…

  8. The ancient Chinese casting techniques

    OpenAIRE

    2011-01-01

    In the course of Chinese civilization, which lasted more than 5,000 years, casting production has made a huge contribution. In this paper, some representative metal castings were presented. According to their forming techniques, they can be grouped into stone mould casting, clay mould casting, ablation casting, lost wax casting, stack casting, permanent mould casting, sand casting, etc. According to their materials, they can be categorized into tin bronze, bimetallic bronze, malleable cast ir...

  9. Effects of slope plate variable and reheating on semi-solid structure of reheating on semi-solid structure of ductile cast iron

    OpenAIRE

    M. Nili-Ahmadabadi; Pahlevani, F.; P. Babaghorbani

    2008-01-01

    Semi-solid metal casting and forming are known as a promising process for a wide range of metal alloys production. In spite of growing application of semi-solid processed light alloys, a few works have been reported about semi-solid processing of iron and steel. In this research inclined plate was used to change dendritic structure of iron to globular one. The effects of length and slope of plate on the casting structure were examined. The results show that the process can effectively change ...

  10. Mathematical model of the component mixture distribution in the molten cast iron during centrifugation (sedimentation)

    Science.gov (United States)

    Bikulov, R. A.; Kotlyar, L. M.

    2014-12-01

    For the development and management of the manufacturing processes of axisymmetric articles with compositional structure by centrifugal casting method [1,2,3,4] is necessary to create a generalized mathematical model of the dynamics of component mixture in the molten cast iron during centrifugation. In article. based on the analysis of the dynamics of two-component mixture at sedimentation, a method of successive approximations to determine the distribution of a multicomponent mixture by centrifugation in a parabolic crucible is developed.

  11. Developing power markets - Development of market place for meeting the demand - Case India, in transition from regulated to competitive structure

    Energy Technology Data Exchange (ETDEWEB)

    Kumar, Pranay; Sarkar, Prabhajit Kumar

    2010-09-15

    Power Market players of developing countries with supply deficit are exposed to a unique combination of price risk and quantity risk which is not the case with developed nations that have taken path of liberalization to open up their power markets. India has one of the largest generation capacities in the world, yet till recently the Indian Power sector was highly regulated. However, the last decade has witnessed many initiatives so as to make the sector market oriented. This paper provides opportunity for developing countries to learn from Indian experience of introducing competition in the power sector.

  12. Gypsum bonded investment for micro-structure casting of ZnAl4

    Institute of Scientific and Technical Information of China (English)

    Yang Chuang; Li Bangsheng; Ren Mingxing; Fu Hengzhi

    2010-01-01

    The effects of sintering temperature on the surface roughness of gypsum bonded investments were investigated to find the appropriate sintering temperature applied for micro-investment casting. The surface roughness tests were carried out at sintering temperatures ranging from room temperature to 1,000 ℃for investment compounds mixed from calcium sulphate α-hemihydrate and quartz powder (wt.%, 6:4; 5:5, 4:6, 3:7). In this experiment, each investment compound was prepared by pouring the investment materials into a plastic bottle with the good surface roughness (Ra ~0.2 urn). DTA-TG curves were measured using a thermal analyzer to investigate the difference of surface roughness at different temperatures. The results show that the surface roughness of gypsum bonded investment is temperature sensitive. The preheating temperature of the mold should be up to 600 ℃, but not over 700 ℃, and the investment compound with 60 % plaster and 40 % quartz powder is applicable for preparing the micro-structures. The micro-structures with 100 Mm diameter were produced in the present studies. The results show that the surface roughness of the casting is only Ra ~0.51 urn, slightly rougher than that of the investment mold.

  13. Network structure and its effects on the strength of Fe-C-Si-Mn alloy castings

    Institute of Scientific and Technical Information of China (English)

    ZHANG Ding-fei; PENG Jian; XU Xing-zhi

    2004-01-01

    Fe-C-Si-Mn alloy castings used as blades in hydroelectric generators are studied and found to contain network structures after some heat treatments. Castings after annealing and normalizing were analyzed by microscope and transmission electron microscopy (TEM). The network formed during annealing was proved by TEM to be pearlite with very fine slices, while that formed during normalizing was proved by TEM and micro-hardness to be martensite or bainite. A theoretical analysis together with experimental studies has proved that the pearlite network is caused by carbon content increase in the interdendritic regions to which carbon atoms transfered from dendritic arms due to lower manganese content there during annealing, while the martensite or bainite network results from the higher hardenability of interdendritic regions where manganese content is higher.Experiments reveal that higher heating temperature or longer heating time enlarges the network size due to manganese homogenization. The network structure has a strengthening function like reinforcing rib, and the smaller the network size, the greater its strengthening capability.

  14. Caste biology and behaviour of Bulbitermes sarawakensis (Isoptera, Nasutitermitinae) in Malaysia

    NARCIS (Netherlands)

    Lommen, S.T.E.; Huis, van A.; Sajap, A.S.

    2004-01-01

    Morphometrics, caste composition and behaviour were studied in Bulbitermes sarawakensis (Isoptera; Nasutitermitinae) in Malaysia. Morphometric studies displayed two larval stages, a presoldier and a soldier caste, two worker castes and different nymphal stages. Four different nymphs with long wings

  15. Announcement on the Ranking List of China's Large Casting Enterprises in 2005

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    @@ China is the largest country in casting production worldwide and with many excellent casting producers. Advanced manufacturing technology, scientific management ideas, enormous economic benefit in these enterprises makes them the pioneers of the national casting industry.

  16. Places of remembrance in citizenship education

    Directory of Open Access Journals (Sweden)

    KInga Majchrzak

    2012-06-01

    Full Text Available The text starts with a short introduction. Then the concept of place is defined and its inherent characteristics are described: its symbolism, multi-sided nature and multidisciplinary connotations. Afterwards the principles of place-based pedagogy are presented and it’s eclectic character is pointed out. Then, attempt is made to explain the idea of the places of remembrance from the standpoint of history and pedagogy. In the final part the author relates to educational potential of places of remembrance and takes a stance on the role of places of remembrance in citizenship education.

  17. Worker caste determination in the army ant Eciton burchellii.

    Science.gov (United States)

    Jaffé, Rodolfo; Kronauer, Daniel J C; Kraus, F Bernhard; Boomsma, Jacobus J; Moritz, Robin F A

    2007-10-22

    Elaborate division of labour has contributed significantly to the ecological success of social insects. Division of labour is achieved either by behavioural task specialization or by morphological specialization of colony members. In physical caste systems, the diet and rearing environment of developing larvae is known to determine the phenotype of adult individuals, but recent studies have shown that genetic components also contribute to the determination of worker caste. One of the most extreme cases of worker caste differentiation occurs in the army ant genus Eciton, where queens mate with many males and colonies are therefore composed of numerous full-sister subfamilies. This high intracolonial genetic diversity, in combination with the extreme caste polymorphism, provides an excellent test system for studying the extent to which caste determination is genetically controlled. Here we show that genetic effects contribute significantly to worker caste fate in Eciton burchellii. We conclude that the combination of polyandry and genetic variation for caste determination may have facilitated the evolution of worker caste diversity in some lineages of social insects.

  18. Virtual Mold Technique in Thermal Stress Analysis during Casting Process

    Institute of Scientific and Technical Information of China (English)

    Si-Young Kwak; Jae-Wook Baek; Jeong-Ho Nam; Jeong-Kil Choi

    2008-01-01

    It is important to analyse the casting product and the mold at the same time considering thermal contraction of the casting and thermal expansion of the mold. The analysis considering contact of the casting and the mold induces the precise prediction of stress distribution and the defect such as hot tearing. But it is difficult to generate FEM mesh for the interface of the casting and the mold. Moreover the mesh for the mold domain spends lots of computational time and memory for the analysis due to a number of meshes. Consequently we proposed the virtual mold technique which only uses mesh of the casting part for thermal stress analysis in casting process. The spring bar element in virtual mold technique is used to consider the contact of the casting and the mold. In general, a volume of the mold is much bigger than that of casting part, so the proposed technique decreases the number of mesh and saves the computational memory and time greatly. In this study, the proposed technique was verified by the comparison with the traditional contact technique on a specimen. And the proposed technique gave satisfactory results.

  19. Formation mechanism of internal cracks in continuously cast slab

    Institute of Scientific and Technical Information of China (English)

    Guosen Zhu; Xinhua Wang; Huixiang Yu; Jiongming Zhang; Wanjun Wang

    2004-01-01

    In order to make clear the formation mechanism of centerline cracks in continuously cast slabs, the form, distribution and other characteristics of the cracks were analyzed. The final solidification point, surface temperature of the slabs and strain in solidifying shell were investigated. The results were that: (1) Five relatively low temperature zones exist on slab surface below the three water spraying nozzles and near the two edges, respectively, which corresponds to the places of centerline cracks and triangle-zone cracks. (2) Centerline cracks and triangle-zone cracks occur because of weak secondary cooling, uneven cooling along slab width,and large variation of roll gap. (3) After minimizing the variation of roll gap and applying the new secondary cooling pattern, the occurring frequency of centerline and triangle-zone cracks minimizes to zero.

  20. Characterization of Bimetallic Castings with an Austenitic Working Surface Layer and an Unalloyed Cast Steel Base

    Science.gov (United States)

    Wróbel, Tomasz

    2014-05-01

    The paper presents the technology of bimetallic castings based on the founding method of layer coating directly in the cast process of the so-called method of mold cavity preparation. The prepared castings consist of two fundamental parts, i.e., the base and the working surface layer. The base part of the bimetallic casting is typical foundry material, i.e., unalloyed cast steel, whereas the working layer is a plate of austenitic alloy steel sort X2CrNi 18-9. The quality of the joint between the base part and the working layer was evaluated on the basis of ultrasonic non-destructive testing and structure examinations containing metallographic macro- and microscopic studies with the use of a light microscope (LOM) with microhardness measurements and a scanning electron microscope (SEM) with microanalysis of the chemical composition (energy dispersive spectroscopy—EDS). On the basis of the obtained results it was confirmed that the decisive phenomena needed to create a permanent joint between the two components of the bimetallic casting are carbon and heat transport in the direction from the high-carbon and hot base material which was poured into the mold in the form of liquid metal to the low-carbon and cold material of the working layer which was placed in the mold cavity in the form of a monolithic insert.

  1. Modeling of Mold Filling and Solidification in Lost Foam Casting

    Institute of Scientific and Technical Information of China (English)

    Fengjun LI; Houfa SHEN; Baicheng LIU

    2003-01-01

    Based on the characteristics of the lost foam casting (LFC) and the artificial neural network technique, a mathematicalmodel for the simulation of the melt-pattern interface movement during the mold filling of LFC has been proposed andexperimentally verified. The simulation results are consistent with the experiments in both the shapes of melt frontand filling sequences. According to the calculated interface locations, the fluid flow and the temperature distributionsduring the mold filling and solidification processes were calculated, and the shrinkage defect of a lost foam ductileiron casting was predicted by considering the mold wall movement in LFC. The simulation method was applied tooptimize the casting design of lost foam ductile iron castings. It is shown that the model can be used for the defectsprediction and for casting design optimization in the practical LFC production.

  2. Effect of casting speed and delay time on the residual stresses in centrifugal casting of aluminium rods

    Directory of Open Access Journals (Sweden)

    Adesoji A. OYEDEJI

    2016-07-01

    Full Text Available Longitudinal slitting technique has been employed to determine the residual stresses in centrifugal cast aluminium rods. Residual stresses were found to decrease with increase in casting speed in the centrifugal casting. The residual stresses of the aluminium rods cast at speeds of 100, 200, 300, 400 and 500rpm and at zero (0 second delay time have lower residual stresses as compared to those cast at the same varying casting speeds at ten (10 seconds delay time. At the different casting speeds, residual stress ratio (g was found to decrease with increase in the casting speeds with values of 40.91%, 31.82%, 22.73%, 13.64% and 9.09% at zero second delay time, while at ten seconds delay time the residual stress ratios were 68.18%, 59.09%, 54.55%, 50.00% and 36.36% respectively. Reduction in residual stress with increase in speed and delay time is attributed to the greater centrifugal forces created by the increasing casting speeds on the solidification of the molten aluminium.

  3. Twin-roll strip casting of magnesium alloys in China

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    The development status of twin-roll strip casting for magnesium alloys in China was summarized as well as the new progress when several kinds of twin-roll strip casting technologies were developed and used.Horizontal twin-roll casting (HTRC) of magnesium alloys has attracted much attention and has been industrialized in China.Vertical twin roll casting(VTRC) of the magnesium alloys can reach a speed of higher than 30 m/min and its research and development are just beginning and exhibit exciting potential.By comparing the process characteristics of the two technologies,the process stability of HTRC for the magnesium alloys is better,and the casting speed and the cooling rate of VTRC for the magnesium alloys are higher.The quality of the products by the two technologies needs to be improved and further investigated.

  4. Relationship Between Casting Distortion, Mold Filling, and Interfacial Heat Transfer in Sand Molds

    Energy Technology Data Exchange (ETDEWEB)

    J. K. Parker; K. A. Woodbury; T. S. Piwonka; Y. Owusu

    1999-09-30

    This project sought to determine the relationship between casting dimensions and interfacial heat transfer in aluminum alloy sand castings. The program had four parts; measurement of interfacial heat transfer coefficients in resin bonded and green sand molds, the measurement of gap formation in these molds, the analysis of castings made in varying gatings, orientations and thicknesses, and the measurement of residual stresses in castings in the as-cast and gate removed condition. New values for interfacial heat transfer coefficients were measured, a novel method for gap formation was developed, and the variation of casting dimensions with casting method, gating, and casting orientation in the mold was documented.

  5. Rayleigh Number Criterion for Formation of A-Segregates in Steel Castings and Ingots

    DEFF Research Database (Denmark)

    Rad, M. Torabi; Kotas, Petr; Beckermann, C.

    2013-01-01

    A Rayleigh number-based criterion is developed for predicting the formation of A-segregates in steel castings and ingots. The criterion is calibrated using available experimental data for ingots involving 27 different steel compositions. The critical Rayleigh number above which A-segregates can...... be expected to form is found to be 17 ± 8. The primary source of uncertainty in this critical value is the dendrite arm spacing. The Rayleigh number criterion of the current study is implemented in a casting simulation code and used to predict A-segregates in three case studies involving steel sand castings......, the primary reason for this over-prediction is persumed to be the presence of a central zone of equiaxed grains in the casting sections. A-segregates do not form when the grain structure is equiaxed. © The Minerals, Metals & Materials Society and ASM International 2013...

  6. A chromatin link to caste identity in the carpenter ant Camponotus floridanus.

    Science.gov (United States)

    Simola, Daniel F; Ye, Chaoyang; Mutti, Navdeep S; Dolezal, Kelly; Bonasio, Roberto; Liebig, Jürgen; Reinberg, Danny; Berger, Shelley L

    2013-03-01

    In many ant species, sibling larvae follow alternative ontogenetic trajectories that generate striking variation in morphology and behavior among adults. These organism-level outcomes are often determined by environmental rather than genetic factors. Therefore, epigenetic mechanisms may mediate the expression of adult polyphenisms. We produced the first genome-wide maps of chromatin structure in a eusocial insect and found that gene-proximal changes in histone modifications, notably H3K27 acetylation, discriminate two female worker and male castes in Camponotus floridanus ants and partially explain differential gene expression between castes. Genes showing coordinated changes in H3K27ac and RNA implicate muscle development, neuronal regulation, and sensory responses in modulating caste identity. Binding sites of the acetyltransferase CBP harbor the greatest caste variation in H3K27ac, are enriched with motifs for conserved transcription factors, and show evolutionary expansion near developmental and neuronal genes. These results suggest that environmental effects on caste identity may be mediated by differential recruitment of CBP to chromatin. We propose that epigenetic mechanisms that modify chromatin structure may help orchestrate the generation and maintenance of polyphenic caste morphology and social behavior in ants.

  7. Effects and Mechanism of Titanium Modification on Structures of Cast Steel ZG270-500

    Institute of Scientific and Technical Information of China (English)

    WANG Haitao; TAN Jiwen; HUANG Liping

    2012-01-01

    The influences of titanium modification on the solidification behavior,shrinkage characteristic and primary austenite refinement of cast steel ZG270-500 smelted in intermediate frequency induction furnace were studied.0.15wt% titanium modification increased the fluidity of the steel liquid,enhanced the feeding capacity of cast steel,changed the dispersed shrinkage porosity to concentrated shrinkage cavity,turned the coarse dendrites into fine equiaxed grain structures and greatly reduced the primary austenite grain size.By scanning electron microscope (SEM) and energy disperse spectroscope (EDS) analysis,it was found that titanium combined with carbon to be solid phase particles TiC,with high melting point,to promote the primary austenite nucleation authentically by non-spontaneous nucleating.The crystal lattice match growing model between γ-Fe and TiC was established.The mechanism of TiC heterogeneous nucleating existed in that the primary austenite grew up by { 111 }γ-Fe parallel to the closest packed plane { 111 } Tic in the crystal orientation γ-Fe//TiC.The crystal planes mismatch δ{111}TiC{111}γ-Fe and the lowest orientation mismatch δTiCγ-Fe were 8.18 %-and 2.25 % respectively almost achieving complete coherent lattice match growing ofaustenite on TiC.

  8. Structural Discrimination – Between a Rock and a Hard Place

    DEFF Research Database (Denmark)

    Skadegaard Thorsen, Mira

    This article examines challenges that arise when discrimination is expressed in communication across perceived differences (inter-cultural communication). More specifically, it looks at how visible minority Danes navigate in regard to structural discrimination (implicit and underlying forms...... of discrimination) imbricated in seemingly neutral everyday communication. It argues that structural discrimination is discursive and constitutive and is expressed in language as well as communicated in the form of naturalizations and embodiments of discrimination. It suggests that structural discrimination is so...

  9. Production and characterization of miro- and nano-features in biomedical alumina and zirconia ceramics using a tape casting route

    NARCIS (Netherlands)

    Domanski, M.; Winnubst, L.; Luttge, R.; Lamers, E.; Walboomers, X.F.; Jansen, J.A.; Gardeniers, H.

    2012-01-01

    A process of micromolding, delivering micro- and nanopatterned ceramic surfaces for biomaterial applications is described in this work. To create the desired structures, tape casting of ceramic slurries on microfabricated silicon mold was used. Several tape casting slurry compositions were tested to

  10. Production and characterization of micro- and nano-features in biomedical alumina and zirconia ceramics using a tape casting route

    NARCIS (Netherlands)

    Domanski, M.; Winnubst, A.J.A.; Luttge, R.; Lamers, E.; Walboomers, X.F.; Jansen, J.; Gardeniers, J.G.E.

    2012-01-01

    A process of micromolding, delivering micro- and nanopatterned ceramic surfaces for biomaterial applications is described in this work. To create the desired structures, tape casting of ceramic slurries on microfabricated silicon mold was used. Several tape casting slurry compositions were tested to

  11. Booking His Place in History

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    Late American Pulitzer Prize-winner John Updike is remembered in China The news of the passing of American literary icon John Updike saddened the whole world.In China,the 76-year-old Pulitzer Prize-winning novelist,who

  12. The Poorest Place in America

    Institute of Scientific and Technical Information of China (English)

    JackeWhite; 李小平

    2000-01-01

    The town has no public parks or swimming pools, no movie theaters, no shopping malls, not even a McDonald's or a WalMart. In fact, business in Lake Providence,Louisiana, is so bad that even the pawnshop has shut down. " The only recreation we

  13. Cast iron - a predictable material

    Directory of Open Access Journals (Sweden)

    Jorg C. Sturm

    2011-02-01

    Full Text Available High strength compacted graphite iron (CGI or alloyed cast iron components are substituting previously used non-ferrous castings in automotive power train applications. The mechanical engineering industry has recognized the value in substituting forged or welded structures with stiff and light-weight cast iron castings. New products such as wind turbines have opened new markets for an entire suite of highly reliable ductile iron cast components. During the last 20 years, casting process simulation has developed from predicting hot spots and solidification to an integral assessment tool for foundries for the entire manufacturing route of castings. The support of the feeding related layout of the casting is still one of the most important duties for casting process simulation. Depending on the alloy poured, different feeding behaviors and self-feeding capabilities need to be considered to provide a defect free casting. Therefore, it is not enough to base the prediction of shrinkage defects solely on hot spots derived from temperature fields. To be able to quantitatively predict these defects, solidification simulation had to be combined with density and mass transport calculations, in order to evaluate the impact of the solidification morphology on the feeding behavior as well as to consider alloy dependent feeding ranges. For cast iron foundries, the use of casting process simulation has become an important instrument to predict the robustness and reliability of their processes, especially since the influence of alloying elements, melting practice and metallurgy need to be considered to quantify the special shrinkage and solidification behavior of cast iron. This allows the prediction of local structures, phases and ultimately the local mechanical properties of cast irons, to asses casting quality in the foundry but also to make use of this quantitative information during design of the casting. Casting quality issues related to thermally driven

  14. In Search of Place Brand Identity

    DEFF Research Database (Denmark)

    Kvistgaard, Hans-Peter; Blichfeldt, Bodil Stilling; Hird, John

    2015-01-01

    Place branding relates both to brand identity (what the place is) and brand image (what the place is/should be in the eyes of external audiences). Brand identity can be perceived as the set of values and attributes that those responsible for marketing and development of a place wish to reinforce...... that arise when trying to establish destination brand identity by means of more inclusive, bottom-up approaches. Drawing on both literature studies and the authors’ active involvement in destination branding across more than 50 Danish destinations, particularly the paper discusses how to decide who to give...

  15. Effects of Cr Content and Annealing Temperature on Microstructure and Wear Characteristics of Cast Ausferrite Nodular Iron

    Institute of Scientific and Technical Information of China (English)

    Jia-peng ZOU; Kazumichi SHIMIZU; Qi-zhou CAI

    2015-01-01

    The effects of Cr content and annealing temperature on abrasive wear characteristics of cast ausferrite nodular iron were investigated with Suga type abrasive wear tester. The surface morphology and Vickers hardness of the tested samples were analyzed by scanning electron microscopy (SEM), digital microscope and Vickers hardness tester. The results show that the cast ausferrite nodular iron could be obtained by alloying with Cr in the as-cast ductile cast iron and permanent mold casting, and the bainite con-tent in the matrix increased with increasing Cr content. However, the decomposition of bainite took place during annealing at 500 °C to 800 °C; especially, at 800 °C, the bainite transformed into a mixture of ifne lamellar pearlite and ferrite matrix structure. The wear loss of specimens was reduced with increasing Cr content in the cast ausferrite nodular iron. The wear loss of the sample cast ausferrite nodular iron with 0.4mass% Cr is the least. The wear loss began to increase while the Cr content is 0.6mass%. The wear loss of annealed ductile irons at different annealing temperatures was higher than that of as-cast samples. During the abrasive wear, the shear stress transformed austenite to martensite, and the hardness of specimens increased and the wear resistance of as-cast duc-tile cast iron was improved.

  16. Scientific paper zircon-based coating for the applications in Lost Foam casting process

    Directory of Open Access Journals (Sweden)

    Prstić Aurel

    2012-01-01

    Full Text Available In this work, a possibility to develop a new zircon-based refractory coating for casting applications was investigated. Optimization of the coating composition with controlled rheological properties was attained by application of different coating components, particularly by application of a new suspension agent and by alteration of coating production procedure. Zircon powder with particle size of 25x10-6 m was used as filler. The zircon sample was investigated by means of the following methods: X-ray diffraction analysis, diffraction thermal analysis and polarized microscope. The shape and grain size were analyzed by means of the PC program package OZARIA 2.5. It was shown that application of this type of water-alcohol-based coating had a positive influence on surface quality, structural and mechanical properties of the castings of cast iron obtained by pouring into sand molds by means of the expandable patterns method (Lost Foam casting process.

  17. Convective Heat Transfer from Castings of Ice Roughened Surfaces in Horizontal Flight

    Science.gov (United States)

    Dukhan, Nihad; Vanfossen, G. James, Jr.; Masiulaniec, K. Cyril; Dewitt, Kenneth J.

    1995-01-01

    A technique was developed to cast frozen ice shapes that had been grown on a metal surface. This technique was applied to a series of ice shapes that were grown in the NASA Lewis Icing Research Tunnel on flat plates. Eight different types of ice growths, characterizing different types of roughness, were obtained from these plates, from which aluminum castings were made. Test strips taken from these castings were outfitted with heat flux gages, such that when placed in a dry wind tunnel, they could be used to experimentally map out the convective heat transfer coefficient in the direction of flow from the roughened surfaces. The effects on the heat transfer coefficient for parallel flow, which simulates horizontal flight, were studied. The results of this investigation can be used to help size heaters for wings, helicopter rotor blades, jet engine intakes, etc., or de-icing for anti-icing applications where the flow is parallel to the iced surface.

  18. Putting Outplacement in Its Place.

    Science.gov (United States)

    Kirk, James J.

    1994-01-01

    Describes the Holistic Outplacement Model (HOM). Briefly discusses each of the three functional elements of the HOM: (1) Regaining Equilibrium; (2) Career Development; and (3) Job Hunting. Model emphasizes Regaining Equilibrium as the initial and most important step in the process. Includes 25 references. (CRR)

  19. Structure and properties of cast and splat-quenched high-entropy Al-Cu-Fe-Ni-Si alloys

    Science.gov (United States)

    Bashev, V. F.; Kushnerov, O. I.

    2017-01-01

    The effect of the composition and cooling rate of the melt on the microhardness, phase composition, and fine-structure parameters of as-cast and splat-quenched (SQ) high-entropy (HE) Al-Cu-Fe-Ni-Si alloys was studied. The quenching was performed by conventional splat-cooling technique. The cooling rate was estimated to be 106 K/s. Components of the studied HE alloys were selected taking into account both criteria for designing and estimating their phase composition, which are available in the literature and based on the calculations of the entropy and enthalpy of mixing, and the difference between atomic radii of components as well. According to X-ray diffraction data, the majority of studied Al-Cu-Fe-Ni-Si compositions are two-phase HE alloys, the structure of which consists of disordered solid solutions with bcc and fcc structures. At the same time, the Al0.5CuFeNi alloy is single-phase in terms of X-ray diffraction and has an fcc structure. The studied alloys in the as-cast state have a dendritic structure, whereas, after splat quenching, the uniform small-grained structure is formed. It was found that, as the volume fraction of bcc solid solution in the studied HE alloys increases, the microhardness increases; the as-cast HE Al-Cu-Fe-Ni-Si alloys are characterized by higher microhardness compared to that of splat-quenched alloys. This is likely due to the more equilibrium multiphase state of as-cast alloys.

  20. The function of +CA suffix in the place names

    Directory of Open Access Journals (Sweden)

    Mehmet Gedizli

    2012-08-01

    Full Text Available The etymological approach generally draws attention to the research on the name of the places in Turkey. Words in Turkish always use the latest addition on narrative and meaning structure. As some additions are used as both meaning and narrative structure, they may refer according to grammar. In this article, by an unorthodox approach, names of the places that +CA suffix name passes are mentioned and the function of this suffix on the names of the places that is effective on finding out the meaning of the name of places is pointed. At the same time, the feature of +CA suffix being derivational affix are showed by the names of the places. The names of the places that are seen in Istanbul, Sakarya, Kocaeli and Düzce provinces form the research material.

  1. Put waste in its place

    CERN Multimedia

    2009-01-01

    It doesn’t take much of an effort to sort waste, but what a difference it can make - to the environment, of course, but also to CERN’s incineration bill. A variety of containers are provided to allow waste to be sorted before disposal, thereby making recycling easier. Everyone knows that sorting waste reduces pollution. By recycling or recovering waste materials, we can reduce the amount of waste that ends up in an incinerator or land-fill, while giving the used material a second life. That reduces the consumption of raw materials and natural resources—and of budget resources. CERN pays lower bill: disposing of a tonne of waste by incineration costs 230 Swiss francs, while a tonne of paper only costs 10 francs to dispose of. The problem is that much of the waste is not properly sorted. "In 2008, out of more than 1600 tonnes of waste we had to incinerate 600 tonnes, which is an enormous figure!" says Martine Auerbach, wh...

  2. Solidification science in cast MMCs: The influence of merton flemings

    Science.gov (United States)

    Rohatgi, Pradeep; Asthana, Rajiv

    2001-09-01

    The solidification science of cast metalmatrix composites (MMC) evolved as a subset of the broad field of solidification of monolithic alloys pioneered by Merton Flemings and his students. As a result of advances in solidification, the cast MMC field has evolved from its early incarnation—employing empirical research to engineer novel materials using versatile and cost-effective casting techniques—to using solidification-science-based approaches to tailor advanced materials for application-specific needs. The current and emerging applications of cast MMCs in a variety of automotive, aerospace, electronic packaging, and consumer-good industries exemplify the maturity of the field and the materials. Innovations in composite-forming techniques and efforts at wider industrial acceptance of MMCs will undoubtedly continue. However, the scientific principles underlying the solidification microstructure evolution that governs the composite properties have become well established, to a great extent, due to Flemings’ early, pioneering work on monolithic alloys and some of his more recent studies on solidification of reinforced metals. This paper reviews some aspects of solidification of discontinuously reinforced cast metals that owe their current understanding to Flemings’ contributions, in particular, the scientific understanding of macro- and microsegregation, fluidity and rheology of multiphase slurries, and stircasting, semi-solid casting, and preform infiltration. Current research to develop and test prototype components made from cast composites, including Al-flyash, Cu-graphite, Al-graphite, Al-alumina, and SiC-Al, is also presented, along with directions for future research.

  3. Dynamic control of crystallinity in polymer film casting process

    Directory of Open Access Journals (Sweden)

    Thananchai Leephakpreeda

    2005-05-01

    Full Text Available This paper presents an approach for dynamic control of crystallinity in polymer film casting process. As known, the transients of crystallization dictate the microstructures of semi-crystalline polymer during solidification. In turn, the properties of finished products can be determined by adjustable variables in polymer film casting process such as temperature of chill roll. In this work, an experimental model of the solidification in film casting process is derived by a system identification technique. This model is used to design a digital feedback controller including a state estimator. The simulation results show the effectiveness of the proposed control technique on an extruded film.

  4. Structure and mechanical properties of as-cast Ti–5Sn–xCr alloys

    Energy Technology Data Exchange (ETDEWEB)

    Hsu, Hsueh-Chuan; Wu, Shih-Ching; Hsu, Shih-Kuang [Department of Dental Technology and Materials Science, Central Taiwan University of Science and Technology, Taiwan, ROC (China); Institute of Biomedical Engineering and Materials Science, Central Taiwan University of Science and Technology, Taiwan, ROC (China); Chen, Chien-Yu [Advanced Materials and BioMaterials Laboratory, Department of Materials Science and Engineering, Da-Yeh University, 168 University Road, Dacun, Changhua 51591, Taiwan, ROC (China); Ho, Wen-Fu, E-mail: fujii@mail.dyu.edu.tw [Advanced Materials and BioMaterials Laboratory, Department of Materials Science and Engineering, Da-Yeh University, 168 University Road, Dacun, Changhua 51591, Taiwan, ROC (China)

    2014-06-01

    In this study, the effects of chromium (Cr) on the structure and mechanical properties of a Ti–5Sn-based system were examined, with an emphasis on improving the strength/modulus ratio. Commercially pure titanium (c.p. Ti) was used as a control. As-cast Ti–5Sn and a series of Ti–5Sn–xCr (x=1, 3, 5, 7, 9, 11 and 13 wt%) alloys prepared by using a commercial arc-melting vacuum-pressure casting system were investigated. X-ray diffraction (XRD) for phase analysis was conducted using a diffractometer. Three-point bending tests were performed on all specimens to evaluate their mechanical properties. The experimental results indicate that the structure and mechanical properties of these alloys changed with the addition of various amounts of Cr. The as-cast Ti–5Sn has a hexagonal α' phase. When 1 wt% Cr was introduced into the Ti–5Sn alloy, the structure essentially stayed the same. When the Cr content was at 3 wt%, retention of the metastable β phase began. When the Cr content was increased to 5 wt% or greater, the β phase was entirely retained. The ω phase was detected in Ti–5Sn–3Cr and Ti–5Sn–5Cr. Ti–5Sn–5Cr, which had the largest quantity of the ω phase, exhibited the highest microhardness value due to the hardening effect of the ω phase. Among all Ti–5Sn-based alloys, the β-phase Ti–5Sn–7Cr alloy had the lowest elastic modulus. It also exhibited higher bending strength/modulus ratios, which at 26.8 were higher than that of c.p. Ti (8.5) and that of Ti–6Al–4V (17.4). Furthermore, the elastically recoverable angle of this alloy (31.0°) was much greater than that of c.p. Ti (2.7°). In the search for better implant materials, the low modulus, ductile property, excellent elastic recovery capability and high strength/modulus ratio of β-phase Ti–5Sn–7Cr make this alloy a promising candidate.

  5. Carbides in Nodular Cast Iron with Cr and Mo

    Directory of Open Access Journals (Sweden)

    S. Pietrowski

    2007-07-01

    Full Text Available In these paper results of elements microsegregation in carbidic nodular cast iron have been presented. A cooling rate in the centre of the cross-section and on the surface of casting and change of moulding sand temperature during casting crystallization and its self-cooling have been investigated. TDA curves have been registered. The linear distribution of elements concentration in an eutectic grain, primary and secondary carbides have been made. It was found, that there are two kinds of carbides: Cr and Mo enriched. A probable composition of primary and secondary carbides have been presented.

  6. Evolution of microstructure in centrifugal cast Al-Cu alloy

    Directory of Open Access Journals (Sweden)

    Sui Yanwei

    2010-02-01

    Full Text Available In this research, the effects of centrifugal radius and mould rotation speed on microstructure in centrifugal-cast Al-Cu alloy have been investigated. The results show that, with increase of the centrifugal radius or mould rotation speed, the grain size of centrifugal-cast Al-Cu alloy decreases gradually, while the content of white phases containing the Al2Cu precipitated from α-phase, divorced eutectic and regular eutectic microstructure increases, leading to higher Cu macrosegregation. The variation level of microstructure in centrifugal-cast Al-Cu alloy at 600 rpm of mould rotation speed is greater than that at 300 rpm.

  7. Effects of casting speed on microstructure and segregation of electromagnetically stirred Aluminum alloy in continuous casting process

    Institute of Scientific and Technical Information of China (English)

    LEE Dock-Young; KANG Suk-Won; CHO Duck-Ho; KIM Ki-Bae

    2006-01-01

    Recently, a semi-solid metal processing has been acknowledged as a cost-effective technique to be able to manufacture high quality product for the transportation industry.In this study a hypo-eutectic Al alloy was fabricated by means of an electromagnetic stirrer in continuous casting process and the microstructural change during solidification due to a fluid flow by electromagnetic stirring was examined.Due to the forced fluid flow during solidification a dendritic phase of primary α phase of Al alloy was turned into a globular phase, which can make the Al alloy get a thixotropic behavior in the semi-solid region.In order to establish the quantitative relationship between microstructure and the process parameters, the morphology shape, a silicon distribution and a size of primary α phase were observed according to casting speed in continuous casting machine.The primary α phase was turned into the degenerate dendrites approaching a spherical configuration with increasing casting speed.The fine-grained and equiaxed microstructure appeared at higher casting speed.A segregation behavior of Si element was declined with increasing casting speed and a very uniform distribution of Si element was observed on the billet at a casting speed of 600 mm·min-1.A thickness of the solidifying shell of the billet was shortened with increasing the casting speed.

  8. Materials for Advanced Ultrasupercritical Steam Turbines Task 4: Cast Superalloy Development

    Energy Technology Data Exchange (ETDEWEB)

    Thangirala, Mani

    2015-09-30

    The Steam Turbine critical stationary structural components are high integrity Large Shell and Valve Casing heavy section Castings, containing high temperature steam under high pressures. Hence to support the development of advanced materials technology for use in an AUSC steam turbine capable of operating with steam conditions of 760°C (1400°F) and 35 Mpa (5000 psia), Casting alloy selection and evaluation of mechanical, metallurgical properties and castability with robust manufacturing methods are mandated. Alloy down select from Phase 1 based on producability criteria and creep rupture properties tested by NETL-Albany and ORNL directed the consortium to investigate cast properties of Haynes 282 and Haynes 263. The goals of Task 4 in Phase 2 are to understand a broader range of mechanical properties, the impact of manufacturing variables on those properties. Scale up the size of heats to production levels to facilitate the understanding of the impact of heat and component weight, on metallurgical and mechanical behavior. GE Power & Water Materials and Processes Engineering for the Phase 2, Task 4.0 Castings work, systematically designed and executed casting material property evaluation, multiple test programs. Starting from 15 lbs. cylinder castings to world’s first 17,000 lbs. poured weight, heavy section large steam turbine partial valve Haynes 282 super alloy casting. This has demonstrated scalability of the material for steam Turbine applications. Activities under Task 4.0, Investigated and characterized various mechanical properties of Cast Haynes 282 and Cast Nimonic 263. The development stages involved were: 1) Small Cast Evaluation: 4 inch diam. Haynes 282 and Nimonic 263 Cylinders. This provided effects of liquidus super heat range and first baseline mechanical data on cast versions of conventional vacuum re-melted and forged Ni based super alloys. 2) Step block castings of 300 lbs. and 600 lbs. Haynes 282 from 2 foundry heats were evaluated which

  9. Safety training: places available in September 2014

    CERN Multimedia

    HSE Unit

    2014-01-01

    There are places available in the forthcoming Safety courses. For updates and registrations, please refer to the Safety Training Catalogue (see here).   Please note that there are 7 places left on the “Territorial Safety Officer (TSO) – Initial” course on September 23-25, 2014 (in French).

  10. Casting defects of Ti-6Al-4V alloy in vertical centrifugal casting processes with graphite molds

    Science.gov (United States)

    Jia, Limin; Xu, Daming; Li, Min; Guo, Jingjie; Fu, Hengzhi

    2012-02-01

    Numerical simulation and experimental investigation are utilized to analyze the casting defects of Ti-6Al-4V alloy formed under different vertical centrifugal casting conditions in graphite molds. Mold rotating rates of 0, 110 and 210 rpm are considered in experimental process. Results show that centrifugal forces have significant effects on the quantity of both macropores and microdefects (micropores, microcracks and inclusions). The relative amount of all macro- and micro-scopic casting defects decreases from 62.4 % to 24.8 % with the increasing of the centrifugal force, and the macropore quantity in stepped casting decreases exponentially with the increase of the gravitation coefficient. The relative proportions of both micropores and microcracks decrease with the mold-rotating rate increase, but the relative proportion of inclusions increases significantly. Besides this, the mold-filling sequence is proved to be an important factor in casting quality control.

  11. Thickness control and interface quality as functions of slurry formulation and casting speed in side-by-side tape casting

    DEFF Research Database (Denmark)

    Bulatova, Regina; Jabbari, Mirmasoud; Kaiser, Andreas;

    2014-01-01

    A novel method of co-casting called side-by-side tape casting was developed aiming to form thin functionally graded films with varying properties within a single plane. The standard organic-based recipe was optimized to co-cast slurries into thick graded tapes. Performed numerical simulations...... identified the stable flow beneath the blade with a shear rate profile independent of slurry viscosity as long as the slurry load in the casting tank was low. Thickness and interface shape could be well predicted if the rheological behaviour of slurries is known and the processing parameters are well......-controlled. A well-defined steep interface was obtained by co-casting slurries with similar viscosities above 4000mPas at a speed of 40cm/min. The elastic properties of green tapes were proven to be defined by the binder concentration in the recipe formulation. The interfaces in graded tapes were shown to withstand...

  12. Effect of Slope Plate Variable and Reheating on the Semi-Solid Structure of Ductile Cast Iron

    Institute of Scientific and Technical Information of China (English)

    M. Nili-Ahmadabadi; F. Pahlevani; P. Babaghorbani

    2008-01-01

    Semi-solid metal casting and forming is a promising production method for a wide range of metal alloys. In spite of many applications for semi-solid processed light alloys, few works have reported on the semi-solid processing of iron and steel. In this research, an inclined plate was used to change the dendritic structure of iron to globular. The effects of the length and slope of the plate on the casting structure were examined. The results show that the process effectively changes the dendritic structure to globular. A sloped plate angle of 7.5° and length of 560 mm with a cooling rate of 67 K·s-1 gave the optimum graphite nodu-larity and solid particle globularity. The results also show that the sloped plate more easily prevents inocu-lant fading since the total time processing is rather short. In addition the semi-solid ductile cast iron prepared using the inclined plate method was reheated to examine the effect of reheating conditions on the micro-structure and coarsening kinetics of the alloy. The solid fractions at different reheating temperatures and holding times were used to find the optimum reheating temperature range.

  13. Central Place Theory and Distribution of Post Offices in Cities

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    The feasibility of application of the Central Place Theory in the distribution of post offices in cities is analysed, the grade scale structure and space distribution structure Shijiazhauang of post offices in city are studied, the research results prove the actual value of the Central Place Theory, and the suggestion of adjustment in the space distribution Shijiazhuang of post offices in city is put forward.

  14. Awareness programs and change in taste-based caste prejudice.

    Science.gov (United States)

    Banerjee, Ritwik; Datta Gupta, Nabanita

    2015-01-01

    Becker's theory of taste-based discrimination predicts that relative employment of the discriminated social group will improve if there is a decrease in the level of prejudice for the marginally discriminating employer. In this paper we experimentally test this prediction offered by Garry Becker in his seminal work on taste based discrimination, in the context of caste in India, with management students (potential employers in the near future) as subjects. First, we measure caste prejudice and show that awareness through a TV social program reduces implicit prejudice against the lower caste and the reduction is sustained over time. Second, we find that the treatment reduces the prejudice levels of those in the left tail of the prejudice distribution--the group which can potentially affect real outcomes as predicted by the theory. And finally, a larger share of the treatment group subjects exhibit favorable opinion about reservation in jobs for the lower caste.

  15. Analysis of nucleation modelling in ductile cast iron

    DEFF Research Database (Denmark)

    Moumeni, Elham; Tutum, Cem Celal; Tiedje, Niels Skat;

    2012-01-01

    Heterogeneous nucleation of nodular graphite at inclusions in ductile iron during eutectic solidification has been investigated. The experimental part of this work deals with casting of ductile iron samples with two different inoculants in four different thicknesses. Chemical analysis...

  16. A Thermal Simulation Method for Solidification Process of Steel Slab in Continuous Casting

    Science.gov (United States)

    Zhong, Honggang; Chen, Xiangru; Han, Qingyou; Han, Ke; Zhai, Qijie

    2016-10-01

    Eighty years after the invention of continuous cast of steels, reproducibility from few mm3 samples in the laboratory to m3 product in plants is still a challenge. We have engineered a thermal simulation method to simulate the continuous casting process. The temperature gradient ( G L ) and dendritic growth rate ( v) of the slab were reproduced by controlling temperature and cooling intensity at hot and chill end, respectively, in our simulation samples. To verify that our samples can simulate the cast slab in continuous casting process, the heat transfer, solidification structure, and macrosegregation of the simulating sample were compared to those of a much larger continuous casting slab. The morphology of solid/liquid interface, solidified shell thickness, and dendritic growth rate were also investigated by in situ quenching the solidifying sample. Shell thickness ( δ) determined by our quenching experiment was related to solidification time ( τ) by equation: δ = 4.27 × τ 0.38. The results indicated that our method closely simulated the solidification process of continuous casting.

  17. Determination of Bulk Dimensional Variation in Castings

    Energy Technology Data Exchange (ETDEWEB)

    Dr. James F. Cuttino Dr. Edward P. Morse

    2005-04-14

    The purpose of this work is to improve the efficiency of green sand foundries so that they may continue to compete as the most cost-effective method of fabrication while meeting tightening constraints on near-net shape manufacturing. In order to achieve this objective, the study is divided into two major components. The first component concentrated on identifying which processes control surface finish on the castings and which provide potential reductions in variations. The second component identified metrological methods that effectively discern between the geometry of bulk material versus surface finish in order to more accurately determine the quality of a part. The research resulted in the determination of an empirical relationship relating pouring parameters to dimensional variation, with an R2 value of greater than 0.79. A significant difference in variations obtained from vertical vs. horizontal molding machines was also noticed. When analyzed separately, however, the resulting empirical relationships for horizontal and vertical machines had reduced R2 values, probably due to the reduced data sets. Significant parameters when considering vertical and horizontal molding machines together included surface roughness, pattern type, iron type, pouring rate, copper content, amount of Western Bentonite, and permeability.

  18. MicroRNAs in Honey Bee Caste Determination

    Science.gov (United States)

    Ashby, Regan; Forêt, Sylvain; Searle, Iain; Maleszka, Ryszard

    2016-01-01

    The cellular mechanisms employed by some organisms to produce contrasting morphological and reproductive phenotypes from the same genome remains one of the key unresolved issues in biology. Honeybees (Apis mellifera) use differential feeding and a haplodiploid sex determination system to generate three distinct organismal outcomes from the same genome. Here we investigate the honeybee female and male caste-specific microRNA and transcriptomic molecular signatures during a critical time of larval development. Both previously undetected and novel miRNAs have been discovered, expanding the inventory of these genomic regulators in invertebrates. We show significant differences in the microRNA and transcriptional profiles of diploid females relative to haploid drone males as well as between reproductively distinct females (queens and workers). Queens and drones show gene enrichment in physio-metabolic pathways, whereas workers show enrichment in processes associated with neuronal development, cell signalling and caste biased structural differences. Interestingly, predicted miRNA targets are primarily associated with non-physio-metabolic genes, especially neuronal targets, suggesting a mechanistic disjunction from DNA methylation that regulates physio-metabolic processes. Accordingly, miRNA targets are under-represented in methylated genes. Our data show how a common set of genetic elements are differentially harnessed by an organism, which may provide the remarkable level of developmental flexibility required. PMID:26739502

  19. MicroRNAs in Honey Bee Caste Determination.

    Science.gov (United States)

    Ashby, Regan; Forêt, Sylvain; Searle, Iain; Maleszka, Ryszard

    2016-01-07

    The cellular mechanisms employed by some organisms to produce contrasting morphological and reproductive phenotypes from the same genome remains one of the key unresolved issues in biology. Honeybees (Apis mellifera) use differential feeding and a haplodiploid sex determination system to generate three distinct organismal outcomes from the same genome. Here we investigate the honeybee female and male caste-specific microRNA and transcriptomic molecular signatures during a critical time of larval development. Both previously undetected and novel miRNAs have been discovered, expanding the inventory of these genomic regulators in invertebrates. We show significant differences in the microRNA and transcriptional profiles of diploid females relative to haploid drone males as well as between reproductively distinct females (queens and workers). Queens and drones show gene enrichment in physio-metabolic pathways, whereas workers show enrichment in processes associated with neuronal development, cell signalling and caste biased structural differences. Interestingly, predicted miRNA targets are primarily associated with non-physio-metabolic genes, especially neuronal targets, suggesting a mechanistic disjunction from DNA methylation that regulates physio-metabolic processes. Accordingly, miRNA targets are under-represented in methylated genes. Our data show how a common set of genetic elements are differentially harnessed by an organism, which may provide the remarkable level of developmental flexibility required.

  20. In-place HEPA filter penetration test

    Energy Technology Data Exchange (ETDEWEB)

    Bergman, W.; Wilson, K.; Elliott, J. [Lawrence Livermore National Lab., CA (United States)] [and others

    1997-08-01

    We have demonstrated the feasibility of conducting penetration tests on high efficiency particulate air (HEPA) filters as installed in nuclear ventilation systems. The in-place penetration test, which is designed to yield equivalent penetration measurements as the standard DOP efficiency test, is based on measuring the aerosol penetration of the filter installation as a function of particle size using a portable laser particle counter. This in-place penetration test is compared to the current in-place leak test using light scattering photometers for single HEPA filter installations and for HEPA filter plenums using the shroud method. Test results show the in-place penetration test is more sensitive than the in-place leak test, has a similar operating procedure, but takes longer to conduct. Additional tests are required to confirm that the in-place penetration test yields identical results as the standard dioctyl phthalate (DOP) penetration test for HEPA filters with controlled leaks in the filter and gasket and duct by-pass leaks. Further development of the procedure is also required to reduce the test time before the in-place penetration test is practical. 14 refs., 14 figs., 3 tabs.

  1. Identification of temperature changes dynamics in selected castings as a contribution to performance life improvement

    Directory of Open Access Journals (Sweden)

    A. Pytel

    2010-07-01

    Full Text Available Parameters describing boundary conditions and dynamics of temperature changes during casting cooling in foundry moulds and thesuccessive performance, especially as regards the massive cast elements, were discussed. Considering the specific nature of castingoperation, non-standard methods of examination of the isotherms of temperature fields on the casting surface were described to determinelocal overheating resulting from the technological process, chemical composition, properties of the currently applied insulation materials,casting defects and/or design. Identification of these parameters can be interpolated to laboratory conditions and to the validation of virtual models subject to computer simulation. The use in simulation of genetic algorithms combined with the results of measurements under real conditions enables more precise determination of the performance parameters, including critical states of stresses present in a structure. This should allow further optimisation of the massive castings design, considering the specific nature of a manufacturing process (alloy composition included, combined with performance parameters. Measures described here are expected to contribute to the reduced casting weight and longer time of operation.

  2. Teaching students in place: the languages of third space learning

    Science.gov (United States)

    Morawski, Cynthia M.

    2016-07-01

    With a perceptive eye cast on geoscience pedagogy for students labeled as disabled, Martinez-Álvarez makes important contributions to the existing conversation on placed-based learning. It is in our local backyards, from the corner basketball court, to the mud bank of a city lake, to the adjacent field where rocky outcrops spill down to a forgotten farmer's field, that we find rich working material for connecting self and community, moving students' out-of-school experiences that feature their cultural and linguistic knowledge, from misconceptions to "alternative conceptions." Informed by her insights regarding the learning of students whose literacy does not match conventional classroom practice, geoscience learning in the place of third space can act as a model of meaning making across the entire curriculum. In the pages that follow, I transact, both aesthetically and efferently, with Martinez-Álvarez's text as she presents her research on special ways of learning in placed-based geoscience explorations with bilingual children experiencing disabilities.

  3. Social interactions affecting caste development through physiological actions in termites.

    Science.gov (United States)

    Watanabe, Dai; Gotoh, Hiroki; Miura, Toru; Maekawa, Kiyoto

    2014-01-01

    A colony of social insects is not only an aggregation of individuals but also a functional unit. To achieve adaptive social behavior in fluctuating environmental conditions, in addition to coordination of physiological status in each individual, the whole colony is coordinated by interactions among colony members. The study on the regulation of social-insect colonies is termed "social physiology." Termites, a major group of social insects, exhibit many interesting phenomena related to social physiology, such as mechanisms of caste regulation in a colony. In their colonies, there are different types of individuals, i.e., castes, which show distinctive phenotypes specialized in specific colony tasks. Termite castes comprise reproductives, soldiers and workers, and the caste composition can be altered depending on circumstances. For the regulation of caste compositions, interactions among individuals, i.e., social interactions, are thought to be important. In this article, we review previous studies on the adaptive meanings and those on the proximate mechanisms of the caste regulation in termites, and try to understand those comprehensively in terms of social physiology. Firstly, we summarize classical studies on the social interactions. Secondly, previous studies on the pheromone substances that mediate the caste regulatory mechanisms are overviewed. Then, we discuss the roles of a physiological factor, juvenile hormone (JH) in the regulation of caste differentiation. Finally, we introduce the achievements of molecular studies on the animal sociality (i.e., sociogenomics) in terms of social physiology. By comparing the proximate mechanisms of social physiology in termites with those in hymenopterans, we try to get insights into the general principles of social physiology in social animals.

  4. Managament quality of tools in the planned housing casting

    Directory of Open Access Journals (Sweden)

    Jaworski J.

    2007-01-01

    Full Text Available The Kaizen method of housing casting designing was presented in the paper. Algorithm making possibility of identification of tools limiting efficienty of tooling process was formulated. The system of tool management consisting of various was shown.

  5. Inverse thermal analysis method to study solidification in cast iron

    DEFF Research Database (Denmark)

    Dioszegi, Atilla; Hattel, Jesper

    2004-01-01

    Solidification modelling of cast metals is widely used to predict final properties in cast components. Accurate models necessitate good knowledge of the solidification behaviour. The present study includes a re-examination of the Fourier thermal analysis method. This involves an inverse numerical...... solution of a 1-dimensional heat transfer problem connected to solidification of cast alloys. In the analysis, the relation between the thermal state and the fraction solid of the metal is evaluated by a numerical method. This method contains an iteration algorithm controlled by an under relaxation term...... was developed in order to investigate the thermal behaviour of the solidifying metal. Three cylindrically shaped cast samples surrounded by different cooling materials were introduced in the same mould allowing a common metallurgical background for samples solidifying at different cooling rates. The proposed...

  6. Whose stories? Whose place? : place politics and the politics of place stories in Tromsø's Olympic debate

    OpenAIRE

    Kielland, Ingrid Marie

    2013-01-01

    Abstract The dissertation explores the relevance and potential of approaching place politics through personal and collective stories about place. It is based on a case study of a local debate over a controversial project to bid for the 2018 Winter Olympic Games in Tromsø, Northern Norway. The dissertation contributes to developing Doreen Massey´s work on the politics of a relational sense of place by looking at how interests and identities, propinquities and connectivities are negotiated a...

  7. Place in Pacific Islands Climate Education

    Science.gov (United States)

    Barros, C.; Koh, M. W.

    2015-12-01

    Understanding place, including both the environment and its people, is essential to understanding our climate, climate change, and its impacts. For us to develop a sense of our place, we need to engage in multiple ways of learning: observation, experimentation, and opportunities to apply new knowledge (Orr, 1992). This approach allows us to access different sources of knowledge and then create local solutions for local issues. It is especially powerful when we rely on experts and elders in our own community along with information from the global community.The Pacific islands Climate Education Partnership (PCEP) is a collaboration of partners—school systems, nongovernmental organizations, and government agencies—working to support learning and teaching about climate in the Pacific. Since 2009, PCEP partners have been working together to develop and implement classroom resources, curriculum standards, and teacher professional learning opportunities in which learners approach climate change and its impacts first through the lens of their own place. Such an approach to putting place central to teaching and learning about climate requires partnership and opportunities for learners to explore solutions for and with their communities. In this presentation, we will share the work unfolding in the Republic of the Marshall Islands (RMI) as one example of PCEP's approach to place-based climate education. Three weeklong K-12 teacher professional learning workshops took place during June-July 2015 in Majuro, RMI on learning gardens, climate science, and project-based learning. Each workshop was co-taught with local partners and supports educators in teaching climate-related curriculum standards through tasks that can foster sense of place through observation, experimentation, and application of new knowledge. Additionally, we will also share PCEP's next steps in place-based climate education, specifically around emerging conversations about the importance of highlighting

  8. Structure and Properties of Cast Near-Congruent Copper-Manganese Alloys

    Science.gov (United States)

    Chaput, Kevin; Trumble, Kevin P.

    2014-10-01

    Microstructure development in the casting of copper-manganese alloys based on the congruent point at 34.6 wt pct Mn and 1146 K (873 °C) has been studied. The alloys were prepared by induction melting of electrolytic Cu and Mn in clay-graphite crucibles in open air. Under conventional casting conditions, the alloys exhibit fine cellular (non-dendritic) solidification morphology with a distinct absence of solidification shrinkage microporosity, and they maintain these attributes over a composition range of approximately 3 wt pct Mn about the congruent point. The high Mn concentration in the alloy admits carbon into solution in the melt, resulting in formation of manganese carbide Mn7C3 particles having two different forms (globular and angular) in the cast microstructure. The Mn carbide was eliminated or controlled to low levels by melting in an alumina or a silicon carbide crucible, or in a clay-graphite crucible at lower temperatures. Microstructure development in casting the alloy was analyzed in terms of the available phase diagrams and thermochemical data. Hardness and tensile testing indicated a potent solid solution strengthening effect of Mn and high ductility in the as-cast condition, with additional hardness (strength) when the alloy contains the Mn carbide phase.

  9. Caste, Class and the Love-Marriage: Social Change in India

    Science.gov (United States)

    Corwin, Lauren A.

    1977-01-01

    The present study of a small town in rural West Bengal, India, reveals a number of "love-marriages" involving individuals from castes of distinctly different ranks in the local caste hierarchy. Despite the prevailing rule of caste endogamy, inter-caste couples appear to face little difficulty. (Author)

  10. Wear Property of Cast Steel Wheel Material in Rail Truck

    Institute of Scientific and Technical Information of China (English)

    MI Guo-fa; LIU Yan-lei; ZHANG Bin; FU Xiu-qin; ZHANG Hong; SONG Guo-xiang

    2009-01-01

    Wear property of material plays a key role in the service time of workpiece.A major objective in the development of new wheel materials is to improve the wear performance.The wear property of B and B+ grade cast steel materials was reported.The results showed that B+ grade cast steel material exhibited better wear property than the B grade material.Carbon content related to the hardness match was the principal factor affecting the wear properties.

  11. A study of interfacial heat transfer and process parameters in squeeze casting and low pressure permanent mold casting

    Science.gov (United States)

    Krishna, Prasad

    2001-08-01

    With the emerging demand for energy efficient and environment-friendly automobiles, cast aluminum alloys are increasingly being used in their manufacture. In this context, two permanent mold casting processes, namely, Squeeze Cast Permanent Mold and Low Pressure Permanent Mold (LPPM) have become very popular in the production of high integrity shape-cast aluminum components. However, many industries are yet to benefit from the full potential of these processes due to limited understanding of the effect of process parameters on casting quality and the necessary boundary conditions for computer modeling and simulation so as to minimize costly field trials. This dissertation attempts to address some of these concerns facing today's foundry industry. An experimental investigation of the Indirect Squeeze Casting Process was conducted by pouring molten Al-7Si-0.3Mg (A356) alloy into a specially designed and instrumented mold, mounted on a horizontal clamped-vertical shot squeeze caster (HVSC). Temperature measurements close to the metal/mold interface were made and compared with the results of the numerical simulation of heat flow during solidification and cooling of castings. The Heat Transfer Coefficient (HTC), a critical parameter essential for any solidification simulation, was estimated based on the simulation that gave the best fit to the experimental temperature data. During the solidification process, the HTC is relatively uniform over the entire casting and on reaching a critical solidification pressure, the HTC is close to 4500 W/m2 K. The work has also provided a correlation of Secondary Dendrite Arm Spacing (SDAS) with cooling rate for a modified A356 alloy. Low Pressure Permanent Mold Casting experiments were conducted by pouring a nearly identical aluminum alloy into an instrumented, coated mold mounted on a low pressure casting machine. The pressure levels, along with the time required to achieve complete filling, were microprocessor controlled in the

  12. Application of 3D stereoscopic visualization technology in casting aspect

    Institute of Scientific and Technical Information of China (English)

    Kang Jinwu; Zhang Xiaopeng; Zhang Chi; Liu Baicheng

    2014-01-01

    3D stereoscopic visualization technology is coming into more and more common use in the field of entertainment, and this technology is also beginning to cut a striking ifgure in casting industry and scientiifc research. The history, fundamental principle, and devices of 3D stereoscopic visualization technology are reviewed in this paper. The authors’ research achievements on the 3D stereoscopic visualization technology in the modeling and simulation of the casting process are presented. This technology can be used for the observation of complex 3D solid models of castings and the simulated results of solidiifcation processes such as temperature, lfuid lfow, displacement, stress strain and microstructure, as wel as the predicted defects such as shrinkage/porosity, cracks, and deformation. It can also be used for other areas relating to 3D models, such as assembling of dies, cores, etc. Several cases are given to compare the illustration of simulated results by traditional images and red-blue 3D stereoscopic images. The spatial shape is observed better by the new method. The prospect of 3D stereoscopic visualization in the casting aspect is discussed as wel. The need for aided-viewing devices is stil the most prominent problem of 3D stereoscopic visualization technology. However, 3D stereoscopic visualization represents the tendency of visualization technology in the future; and as the problem is solved in the years ahead, great breakthroughs wil certainly be made for its application in casting design and modeling and simulation of the casting processes.

  13. Bimetallic layered castings alloy steel – carbon cast steel

    Directory of Open Access Journals (Sweden)

    T. Wróbel

    2011-01-01

    Full Text Available In paper is presented technology of bimetallic layered castings based on founding method of layer coating directly in cast processso-called method of mould cavity preparation. Prepared castings consist two fundamental parts i.e. bearing part and working part (layer. The bearing part of bimetallic layered casting is typical foundry material i.e. ferritic-pearlitic carbon cast steel, whereas working part (layer is plate of austenitic alloy steel sort X10CrNi 18-8. The ratio of thickness between bearing and working part is 8:1. The quality of the bimetallic layered castings was evaluated on the basis of ultrasonic NDT (non-destructive testing, structure and macro- and microhardness researches.

  14. Geographic Place Names, Published in unknown, SWGRC.

    Data.gov (United States)

    NSGIC GIS Inventory (aka Ramona) — This Geographic Place Names dataset as of unknown. Data by this publisher are often provided in Geographic coordinate system; in a Not Sure projection; The extent...

  15. Graphite formation in cast iron, phase 2

    Science.gov (United States)

    Stefanescu, D. M.; Fiske, M. R.

    1985-01-01

    Several types of cast irons are directionally solidified aboard the KC-135 aircraft. Also, control samples are run on Earth for comparison. Some of these samples are unusable because of various mechanical problems; the analysis and the interpretation of results on the samples that are run successfully is discussed.

  16. Stereology of carbide phase in modified hypereutectic chromium cast iron

    Directory of Open Access Journals (Sweden)

    J. Suchoń

    2010-04-01

    Full Text Available In paper are presented results of studies of carbide phase stereology modified hypereutectic wear resistance chromium cast iron which contains carbon about 3,5% and chromium about 25%. Three substances were applied to the modification: boron carbide (B4C, ferroniobium (FeNb and mixture of ferroniobium and rare-earth (RE. The measurements of geometrical features of carbides were conducted on microsection taken from castings wich were cooled with various velocities.

  17. Analysis of pile-soil stress ratio of cast-in-place X-section concrete pile composite foundation under rigid base%刚性基础下现浇X形桩复合地基桩-土应力比分析

    Institute of Scientific and Technical Information of China (English)

    吕亚茹; 丁选明; 刘汉龙; 崔允亮

    2012-01-01

    As one of the most important factors, pile-soil stress ratio can reflect the load transfer and deformation mechanism of composite foundation. Up to now, as a new pile, no uniform method has been found to calculate the pile-soil stress ratio for X-section pile. Sedimentation basin and filter chamber are typical buildings with concrete floor plate that is considered to be a rigid base. The bearing capacity of pile composite foundation under the rigid base is different from which under the soft base. The in-situ static load tests are carried out based on the foundation treatment project in Qiaobei sewage treatment plant. Besides, a finite element model is built to simulate the cast-in-place X-section concrete pile composite foundation under the rigid base by software ABAQUS. The pile-soil stress ratios are discussed considering some factors including elastic modulus of pile, compression modulus of surrounding soil, pile lengths, cushion thicknesses and compression modulus. The results reveal that the pile-soil stress ratio increases with the increasing of pile modulus, cushion modulus and pile length, while reduces with the increasing of modulus of surrounding soil and cushion thickness. The reasonable pile-soil stress ratio of X-section pile ranges from 20 to 25, corresponding to the pile modulus from 10 to 20 GPa, the cushion thickness from 20 to 40 cm, and the cushion modulus from 30 to 45 MPa.%桩土应力比是反映复合地基承载特性的重要参数之一,可反映复合地基的荷载传递和变形机制.做为一种新型桩,目前尚未得出统一的计算X形桩复合地基桩土应力比的公式.沉淀池、滤池等构筑物是典型的具有混凝土底板(刚性基础)的结构,刚性基础下桩复合地基的承载性能有别于柔性基础.故结合南京桥北污水处理厂地基处理工程做现场静载荷试验,应用有限元软件ABAQUS建立刚性荷载板下现浇X形混凝土桩复合地基的模型,模拟不同桩身弹性模量

  18. Influences of copper on solidification structure and hardening behavior of high chromium cast irons

    Institute of Scientific and Technical Information of China (English)

    WANG Jun; XIONG Ji; FAN Hong-yuan; SHEN Bao-luo; GAO Sheng-ji

    2008-01-01

    The influences of copper on microstructure and the hardening behavior of high chromium cast irons subjected to sub-critical treatment were investigated.The results show that the mierostructure of the as-cast high chromium cast irons consists of retained austenite,martensite and M7 C3 type eutectic carbide.When copper is added into high chromium cast irons,austenite and carbide contents are increased.The increased addition of copper content from 0%to 1.84%leads to the increase of austenite and carbide from 15.9%and 20.0% to 61.0%and 35.5%,respectively.In the process of sub-critical treatment,the retained austenite in the matrix can be precipitated into secondary carbides and then transforms into martensite in cooling process,which causes the secondary hardening of the alloy under sub-critical treatment.High chromium cast irons containing copper in sub-critical treatment appear the second hardening curve peak due to the precipitation of copper from supersaturated matrix.

  19. Tibia Shaft Fractures in Adolescents: How and When Can They be Managed Successfully With Cast Treatment?

    Science.gov (United States)

    Ho, Christine A

    2016-06-01

    Despite the increasing popularity of operative treatment in adolescent tibia fractures, casting remains a viable first-line treatment. Because the selection bias in published reports does not allow direct comparison between casting and flexible nail treatment of closed pediatric tibia fractures, it is unclear whether flexible nailing offers any advantages over casting. This overview discusses parameters of acceptable alignment, indications, techniques for successful reduction and casting, subsequent inpatient and outpatient management including wedging of casted tibia fractures, expected outcomes, and comparison of casting with flexible nailing. As with any orthopaedic procedure, careful attention to patient selection, indications, and detail facilitates successful cast treatment in this older pediatric population.

  20. Lightweight Concrete Produced Using a Two-Stage Casting Process

    Directory of Open Access Journals (Sweden)

    Jin Young Yoon

    2015-03-01

    Full Text Available The type of lightweight aggregate and its volume fraction in a mix determine the density of lightweight concrete. Minimizing the density obviously requires a higher volume fraction, but this usually causes aggregates segregation in a conventional mixing process. This paper proposes a two-stage casting process to produce a lightweight concrete. This process involves placing lightweight aggregates in a frame and then filling in the remaining interstitial voids with cementitious grout. The casting process results in the lowest density of lightweight concrete, which consequently has low compressive strength. The irregularly shaped aggregates compensate for the weak point in terms of strength while the round-shape aggregates provide a strength of 20 MPa. Therefore, the proposed casting process can be applied for manufacturing non-structural elements and structural composites requiring a very low density and a strength of at most 20 MPa.

  1. FEM Analysis of Physical Field in Level Rolling Process of Inversion Casting by ANSYS Program

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    The strain physical field in level rolling process of inversion casting was analyzed by ANSYS program. Plastics train, stress and displacement were gained. The results show that only surfaces train takes place; the maximum stress exists in the geometrical deformation zone ; In the deformation transition zone and the part leaving the rollers, different stress exists. The rolling force estimated with ANSYS program corresponds to those measured.

  2. Partial corrosion casting to assess cochlear vasculature in mouse models of presbycusis and CMV infection.

    Science.gov (United States)

    Carraro, Mattia; Park, Albert H; Harrison, Robert V

    2016-02-01

    Some forms of sensorineural hearing loss involve damage or degenerative changes to the stria vascularis and/or other vascular structures in the cochlea. In animal models, many methods for anatomical assessment of cochlear vasculature exist, each with advantages and limitations. One methodology, corrosion casting, has proved useful in some species, however in the mouse model this technique is difficult to achieve because digestion of non vascular tissue results in collapse of the delicate cast specimen. We have developed a partial corrosion cast method that allows visualization of vasculature along much of the cochlear length but maintains some structural integrity of the specimen. We provide a detailed step-by-step description of this novel technique. We give some illustrative examples of the use of the method in mouse models of presbycusis and cytomegalovirus (CMV) infection.

  3. Study of carbon and silicon loss through oxidation in cast iron base metal using rotary furnace for melting

    Directory of Open Access Journals (Sweden)

    Sylvester Olanrewaju OMOLE

    2015-05-01

    Full Text Available The projection of loss of carbon and silicon through oxidation is uncertain phenomenon depending on the furnace used for melting, which affect the carbon equivalent value (CEV of cast iron produced. CEV enhances the fluidity of molten metal as well as having great effects on the mechanical properties of cast products. Study on the way elemental loss takes place during melting with rotary furnace will give idea of approach to minimize the loss. Therefore, the aim of this work is to study the magnitude of the elemental loss with rotary furnace and means to minimize the loss. 60kg of grey cast iron scrap was charged into rotary furnace of 100kg capacity after preheating the furnace for 40 minutes. Graphite and ferrosilicon was added to the charge in order to obtain a theoretical composition of not less than 4.0% carbon and 2.0% silicon. Charges in the furnace were heated to obtain molten metal which was tapped at 1400°C. Tapping was done for casting at three different times. The castings solidified in sand mould and allowed to cool to room temperature in the mould. Castings were denoted as sample 1, 2 and 3. Final compositions of each casting were analyzed with optical light emission spectrometer. Sample 1 has 2.95% carbon and 1.82% silicon. Sample 2 has 2.88% carbon and 1.70% silicon and sample 3 has 2.75% carbon and 1.63% silicon.

  4. Market Design in Chinese Market Places

    OpenAIRE

    Krug, Barbara; Hendrischke, Hans

    2012-01-01

    textabstractThe market design (MD) approach to institutional analysis provides the analytical tools to evaluate endogenous institution building in local market places irrespective of the institutional setting of the national economy. Implicit in this analysis of endogenous institution building at the market place level is the recognition of institutional diversity, which none of the conventional forms of institutional analysis can provide. We extend the MD approach from its original game theo...

  5. Nodular cast iron and casting monitoring

    Directory of Open Access Journals (Sweden)

    S. Pietrowski

    2008-10-01

    Full Text Available In this paper quality monitoring of nodular cast iron and casting made of it is presented. A control system of initial liquid cast iron to spheroidization, after spheroidization and inoculation with using of TDA method was shown. An application of an ultrasonic method to assessment of the graphite form and the metal matrix microstructure of castings was investigated.

  6. Nodular cast iron and casting monitoring

    OpenAIRE

    2008-01-01

    In this paper quality monitoring of nodular cast iron and casting made of it is presented. A control system of initial liquid cast iron to spheroidization, after spheroidization and inoculation with using of TDA method was shown. An application of an ultrasonic method to assessment of the graphite form and the metal matrix microstructure of castings was investigated.

  7. The effect of remelting on the melt and casting quality in Al–7%Si–Mg castings

    Energy Technology Data Exchange (ETDEWEB)

    Eisaabadi B, Ghasem [Department of Materials Science and Engineering, Sharif University of Technology, Tehran (Iran, Islamic Republic of); Foundry Technology Center, Korea Institute of Industrial Technology, Incheon (Korea, Republic of); Department of Materials Science and Engineering, Faculty of Engineering, Arak University, Arak (Iran, Islamic Republic of); Tiryakioğlu, Murat, E-mail: m.tiryakioglu@unf.edu [School of Engineering, University of North Florida Jacksonville, FL 32224 (United States); Davami, Parviz [Department of Materials Science and Engineering, Sharif University of Technology, Tehran (Iran, Islamic Republic of); Kim, Shae-Kwang; Yoon, Yong Ok; Yeom, Gil-Yong; Kim, Nam-Seok [Foundry Technology Center, Korea Institute of Industrial Technology, Incheon (Korea, Republic of)

    2014-05-01

    An experiment was conducted to determine whether allowing an aluminum melt to solidify in the crucible and later remelting it would improve the quality of the melt and the casting. To investigate this, data were collected through reduced pressure test, density measurement, metallography, X-ray radiography and tensile testing and analyzed statistically. Results indicated that remelting improved the quality of the melt by reduction of the number of defects in the casting and their area and volume fractions. The improvement in elongation of remelted specimens was found to be statistically significant. Analysis of deformation characteristics showed that the improvement in elongation is due to the improved casting quality after remelting.

  8. Structural durability criteria for commercial vehicle components from the self strengthening cast ausferrite nodular iron EN-GJS-800-8 (ADI) in comparison to the ferritic EN-GJS-400-15

    Energy Technology Data Exchange (ETDEWEB)

    Zinke, R.; Heinrietz, A.; Heim, R.; Hanselka, H. [Fraunhofer Institut fuer Betriebsfestigkeit LBF, Darmstadt (Germany); Streicher, M. [MAN Nutzfahrzeuge AG, Munich (Germany); Sonsino, C.M.

    2008-10-15

    The structural durability of safety components in the chassis comprises not only the fatigue behaviour under cyclic variable amplitude service loading, but also its interaction with prestrains caused by special events and the rupture behaviour under impact loading due to misuse. From this background, the structural durability behaviour of Panhard rods made from ferritic cast nodular iron EN-GJS-400-15 was compared with the behaviour of rods made from the austempered EN-GJS-800-8. The components investigated, Panhard rods and cast plugs, made from the austempered material revealed a higher impact resistance than the components made from the ferritic cast nodular iron. Due to their ausferrite microstructure, Panhard rods made from EN-GJS-800-8 display a significantly superior fatigue strength behaviour, especially under spectrum loading, and offer a potential for lightweight design. Prestrains do not affect the fatigue behaviour under variable amplitude loading and the plastic deformation of the component under impact loading can be increased by appropriate design reducing the stiffness in the shaft area and achieving a weight reduction by 15 %. (Abstract Copyright [2008], Wiley Periodicals, Inc.) [German] Die Betriebsfestigkeit von Fahrwerksbauteilen wird nicht nur von der Schwingfestigkeit unter zyklischen Betriebsbelastungen und Missbrauchsbelastungen bestimmt, sondern auch durch die Interaktion mit Sonderbelastungen und Missbrauchsbelastungen. Vor diesem Hintergrund wird anhand eines Panhard-Stabes, ein stabilisierendes Element im Fahrwerk von Nutzfahrzeugen, gezeigt, wie zunaechst durch eine Werkstoffsubstitution, naemlich des konventionellen Eisengraphitgusses EN-GJS-400-15 (GGG 40), durch die ADI (Ausferrite Ductile Iron)-Variante EN-GJS-800-8 mit der entsprechenden Waermebehandlung eine deutlich hoehere Schwingfestigkeit erzielt wird. Zu bemerken ist, dass der ADI-Guss gefuegebedingt gegenueber dem konventionellen ferritischen Werkstoff unter variablen

  9. Optimization of casting defects analysis with supply chain in cast iron foundry process

    Directory of Open Access Journals (Sweden)

    C. Narayanaswamy

    2016-10-01

    Full Text Available Some of the foundries are in need of meeting production targets and due to the urgency they ignore the rejections. The objective of this paper is to analyze the various defects, [1] from molding process in a cast iron foundry. The Failure Mode Effects Analysis (FMEA in quality control [2-6] with suitable supply chain for mold making process considering rejection rates are identified and analyzed in terms of Risk Priority Number (RPN to prioritize the attention for each of the problem. The optimum levels of selected parameters [7] are obtained in this analysis.

  10. The role of graphite morphology and matrix structure on low frequency thermal cycling of cast irons

    Indian Academy of Sciences (India)

    S Y Buni; N Raman; S Seshan

    2004-02-01

    Low frequency thermal cycling tests were carried out on four types of cast iron (viz., austempered ductile iron, pearlitic ductile iron, compacted/vermicular graphite iron and grey cast iron) at predetermined ranges of thermal cycling temperatures. The specimens were unconstrained. Results show that austempered ductile iron has the highest thermal cycling resistance, followed by pearlitic ductile iron and compacted graphite iron, while grey cast iron exhibits the lowest resistance. Microstructural analysis of test specimens subjected to thermal cycling indicates that matrix decomposition and grain growth are responsible for the reduction in hardness while graphite oxidation, de-cohesion and grain boundary separation are responsible for the reduction in the modulus of elasticity upon thermal cycling.

  11. An Experimental Investigation to Facilitate an Improvement in the Design of an Electromagnetic Continuous Casting Mould

    Directory of Open Access Journals (Sweden)

    Lintao Zhang

    2016-04-01

    Full Text Available An electromagnetic continuous casting mould designed is proposed with a non-uniform slit distribution structure. This design has aimed to reduce the number of slits so that the mould’s strength is enhanced, whilst maintaining a similar metallurgy effect. In this paper, the metallurgy effect for the designed mould is investigated through the magnetic field distribution along the casting direction, the uniformity feature in the vicinity of the meniscus region, the temperature variation of the molten alloy pool and the mould wall. The results show that the designed mould achieved a similar effect as compared to the original mould; however, the configuration is simplified. This research highlights the topic of mould structure optimization, which would enable the Electromagnetic continuous casting (EMCC technique to be utilized with greater ease by industry.

  12. Caste System

    OpenAIRE

    Hoff, Karla

    2016-01-01

    In standard economics, individuals are rational actors and economic forces undermine institutions that impose large inefficiencies. The persistence of the caste system is evidence of the need for psychologically more realistic models of decision-making in economics. The caste system divides South Asian society into hereditary groups whose lowest ranks are represented as innately polluted. ...

  13. Putting sex education in its place.

    Science.gov (United States)

    Cassell, C

    1981-04-01

    In order to help reduce fears and anxieties regarding the influence of sex education in a public school setting, school and community sexuality educators need to better articulate the difference between formal and structured sex education and non-formal, informal and incidental sex learning. Sex education is only 1 aspect of the sexual learning process. 2 main points have to be clarified for parents and the general public to set the stage for a new way to view the school and community involvement in the sexual learning process: the schools' sexuality education courses constitute only a small portion of the sexual learning process; and sexual learning is not an event for youth only, but a process spanning life. Sex education (the process) connotates an academic setting with a specific curricula taught by a trained instructor, but sexual learning relates to environmental, non-formal incidental learning from a multitude of sources. Studies indicate that teenagers receive about 90% of their contraceptive and sexuality informaation from peers and mass media and that these sources of information are becoming their preferred sources of sex education. What is needed is a way to address and improve the conditions of sexual learning in the community. As home is the ideal environment for primary and positive sexual learning, parents need support in their role as sex educators. Classroom sexuality education curricula in all school settings have a solid place in the process of sexual learning.

  14. The UK Casting Industry

    Institute of Scientific and Technical Information of China (English)

    Jincheng Liu

    2006-01-01

    The casting production in the UK in 2004 is presented and analysed. The UK casting industry has played an important role in world casting and manufacturing production. However recent years the rapid development of some developing countries has been shifting the casting production from the western industrialized countries including the UK. The UK casting industry and associated research and technology organizations, universities have been working together very hard to face the serious competition to make the UK casting industry have a sustainable future. The UK casting industry remains strong and plays an important role in world casting and manufacturing production.

  15. Sex and caste-specific variation in compound eye morphology of five honeybee species.

    Directory of Open Access Journals (Sweden)

    Martin Streinzer

    Full Text Available Ranging from dwarfs to giants, the species of honeybees show remarkable differences in body size that have placed evolutionary constrains on the size of sensory organs and the brain. Colonies comprise three adult phenotypes, drones and two female castes, the reproductive queen and sterile workers. The phenotypes differ with respect to tasks and thus selection pressures which additionally constrain the shape of sensory systems. In a first step to explore the variability and interaction between species size-limitations and sex and caste-specific selection pressures in sensory and neural structures in honeybees, we compared eye size, ommatidia number and distribution of facet lens diameters in drones, queens and workers of five species (Apis andreniformis, A. florea, A. dorsata, A. mellifera, A. cerana. In these species, male and female eyes show a consistent sex-specific organization with respect to eye size and regional specialization of facet diameters. Drones possess distinctly enlarged eyes with large dorsal facets. Aside from these general patterns, we found signs of unique adaptations in eyes of A. florea and A. dorsata drones. In both species, drone eyes are disproportionately enlarged. In A. dorsata the increased eye size results from enlarged facets, a likely adaptation to crepuscular mating flights. In contrast, the relative enlargement of A. florea drone eyes results from an increase in ommatidia number, suggesting strong selection for high spatial resolution. Comparison of eye morphology and published mating flight times indicates a correlation between overall light sensitivity and species-specific mating flight times. The correlation suggests an important role of ambient light intensities in the regulation of species-specific mating flight times and the evolution of the visual system. Our study further deepens insights into visual adaptations within the genus Apis and opens up future perspectives for research to better understand the

  16. Sex and caste-specific variation in compound eye morphology of five honeybee species.

    Science.gov (United States)

    Streinzer, Martin; Brockmann, Axel; Nagaraja, Narayanappa; Spaethe, Johannes

    2013-01-01

    Ranging from dwarfs to giants, the species of honeybees show remarkable differences in body size that have placed evolutionary constrains on the size of sensory organs and the brain. Colonies comprise three adult phenotypes, drones and two female castes, the reproductive queen and sterile workers. The phenotypes differ with respect to tasks and thus selection pressures which additionally constrain the shape of sensory systems. In a first step to explore the variability and interaction between species size-limitations and sex and caste-specific selection pressures in sensory and neural structures in honeybees, we compared eye size, ommatidia number and distribution of facet lens diameters in drones, queens and workers of five species (Apis andreniformis, A. florea, A. dorsata, A. mellifera, A. cerana). In these species, male and female eyes show a consistent sex-specific organization with respect to eye size and regional specialization of facet diameters. Drones possess distinctly enlarged eyes with large dorsal facets. Aside from these general patterns, we found signs of unique adaptations in eyes of A. florea and A. dorsata drones. In both species, drone eyes are disproportionately enlarged. In A. dorsata the increased eye size results from enlarged facets, a likely adaptation to crepuscular mating flights. In contrast, the relative enlargement of A. florea drone eyes results from an increase in ommatidia number, suggesting strong selection for high spatial resolution. Comparison of eye morphology and published mating flight times indicates a correlation between overall light sensitivity and species-specific mating flight times. The correlation suggests an important role of ambient light intensities in the regulation of species-specific mating flight times and the evolution of the visual system. Our study further deepens insights into visual adaptations within the genus Apis and opens up future perspectives for research to better understand the timing mechanisms

  17. Structure and properties of Fe-Cr-Mo-C bulk metallic glasses obtained by die casting method

    Directory of Open Access Journals (Sweden)

    W. Pilarczyk

    2010-09-01

    Full Text Available urpose: The goal of this work is to investigate structure and properties of Fe54Cr16Mo12C18 alloy rods with different diameters obtained by the pressure die casting method.Design/methodology/approach: Master alloy ingot with compositions of Fe54Cr16Mo12C18 was prepared by induction melting of pure Fe, Cr, Mo, C elements in argon atmosphere. The investigated material were cast in form of rods with different diameters. Glassy and crystalline structures were examined by X-ray diffraction. The microscopic observation of the fracture morphology was carried out by the SEM with different magnification. The thermal properties of the studied alloy were examined by DTA and DSC method.Findings: These materials exhibit high glass-forming ability, excellent mechanical properties and corrosion resistance.Research limitations/implications: It is difficult to obtain a metallic glass of Fe54Cr16Mo12C18 alloy. The investigations carried out on the different samples of Fe54Cr16Mo12C18 bulk metallic alloy allowed to state that the studied ribbon was amorphous whereas rods were amorphous – crystalline.Originality/value: The formation and investigation of the casted Fe-Cr-Mo-C bulk materials and the study of glass-forming ability of this alloy.

  18. An Integrated Architecture for Enhanced Structuring of Mobile Market Place

    Directory of Open Access Journals (Sweden)

    Amer Ali Sallam

    2011-02-01

    Full Text Available This paper aims at presenting an integrated architecture for mobile marketplace for efficient transaction and marketing using mobile devices and related infrastructure. This architecture deals with different components of mobile marketplace and it considering a new way of integrating different functionalities of mobile market place. .

  19. An Integrated Architecture for Enhanced Structuring of Mobile Market Place

    Directory of Open Access Journals (Sweden)

    Amer Ali Sallam

    2011-01-01

    Full Text Available This paper aims at presenting an integrated architecture for mobile marketplace for efficient transaction and marketing using mobile devices and related infrastructure. This architecture deals with different components of mobile marketplace and it considering a new way of integrating different functionalities of mobile market place. .

  20. Yield improvement and defect reduction in steel casting

    Energy Technology Data Exchange (ETDEWEB)

    Kent Carlson

    2004-03-16

    This research project investigated yield improvement and defect reduction techniques in steel casting. Research and technology development was performed in the following three specific areas: (1) Feeding rules for high alloy steel castings; (2) Unconventional yield improvement and defect reduction techniques--(a) Riser pressurization; and (b) Filling with a tilting mold; and (3) Modeling of reoxidation inclusions during filling of steel castings. During the preparation of the proposal for this project, these areas were identified by the High Alloy Committee and Carbon and Low Alloy Committee of the Steel Founders' Society of America (SFSA) as having the highest research priority to the steel foundry industry. The research in each of the areas involved a combination of foundry experiments, modeling and simulation. Numerous SFSA member steel foundries participated in the project through casting trials and meetings. The technology resulting from this project will result in decreased scrap and rework, casting yield improvement, and higher quality steel castings produced with less iteration. This will result in considerable business benefits to steel foundries, primarily due to reduced energy and labor costs, increased capacity and productivity, reduced lead-time, and wider use and application of steel castings. As estimated using energy data provided by the DOE, the technology produced as a result of this project will result in an energy savings of 2.6 x 10{sup 12} BTU/year. This excludes the savings that were anticipated from the mold tilting research. In addition to the energy savings, and corresponding financial savings this implies, there are substantial environmental benefits as well. The results from each of the research areas listed above are summarized.

  1. Conical surface structures on model thin-film electrodes and tape-cast electrode materials for lithium-ion batteries

    Science.gov (United States)

    Kohler, R.; Proell, J.; Bruns, M.; Ulrich, S.; Seifert, H. J.; Pfleging, W.

    2013-07-01

    Three-dimensional structures in cathode materials for lithium-ion batteries were investigated in this study. For this purpose, laser structuring of lithium cobalt oxide was investigated at first for a thin-film model system and in a second step for conventional tape-cast electrode materials. The model thin-film cathodes with a thickness of 3 μm were deposited using RF magnetron sputtering on stainless steel substrates. The films were structured via excimer laser radiation with a wavelength of 248 nm. By adjusting the laser fluence, self-organized conical microstructures were formed. Using conventional electrodes, tape-cast cathodes made of LiCoO2 with a film thickness of about 80 μm on aluminum substrates were studied. It was shown that self-organizing surface structures could be formed by adjustment of the laser parameters. To investigate the formation mechanisms of the conical topography, the element composition was studied by time-of-flight secondary ion mass spectrometry and X-ray photoelectron spectroscopy. Electrochemical cycling using a lithium anode and conventional electrolyte was applied to study the influence of the laser processing procedures on cell performance. For the model electrode system, a significantly higher discharge capacity of 80 mAh/g could be obtained after 110 cycles by laser structuring compared to 8 mAh/g of the unstructured thin film. On conventional tape-cast electrodes self-organized surface structures could also increase the cycling stability resulting in an 80 % increase in capacity after 110 cycles in comparison to the unstructured electrode.

  2. Solidification microstructure of M2 high speed steel by different casting technologies

    OpenAIRE

    Zhou Xuefeng; Fang Feng; Jiang Jianjing

    2011-01-01

    The present work investigated the solidification microstructure of AISI M2 high speed steel manufactured by different casting technologies, namely iron mould casting and continuous casting. The results revealed that the as-cast structure of the steel was composed of the iron matrix and the M2C eutectic carbide networks, which were greatly refined in the ingot made by continuous casting process, compared with that by the iron mould casting process. M2C eutectic carbides presented variation in ...

  3. Casting materials

    Energy Technology Data Exchange (ETDEWEB)

    Chaudhry, Anil R. (Xenia, OH); Dzugan, Robert (Cincinnati, OH); Harrington, Richard M. (Cincinnati, OH); Neece, Faurice D. (Lyndurst, OH); Singh, Nipendra P. (Pepper Pike, OH)

    2011-06-14

    A foam material comprises a liquid polymer and a liquid isocyanate which is mixed to make a solution that is poured, injected or otherwise deposited into a corresponding mold. A reaction from the mixture of the liquid polymer and liquid isocyanate inside the mold forms a thermally collapsible foam structure having a shape that corresponds to the inside surface configuration of the mold and a skin that is continuous and unbroken. Once the reaction is complete, the foam pattern is removed from the mold and may be used as a pattern in any number of conventional casting processes.

  4. Influence of cooling rate on the structure and mechanical properties of G17CrMoV5 – 10 cast steel

    Directory of Open Access Journals (Sweden)

    G. Golański

    2009-07-01

    Full Text Available The paper presents results of research on the influence of cooling rate on the structure and properties of G17CrMoV5 – 10 (L17HMF cast steel. The material for research was a section taken out from an outer cylinder of a steam turbine body after about 250 000 hours of operation at the temperature of 535°C and pressure 9 MPa. The investigated cast steel was subjected to heat treatment which consisted in cooling at the rates corresponding to the processes, such as: bainitic hardening, normalizing and full annealing. Tempering after the process of cooling from austenitizing temperature was carried out at the temperatures of: 700, 720 and 740°C. Performed research has proved that structures obtained after bainitic hardening and normalizing are characterized by a large strength margin which allows to apply high temperatures of tempering. It has been shown that the cast steel of bainitic structure, with similar mechanical properties as the cast steel of bainitic – ferritic structure, is characterized by almost twice as high impact energy. Full annealing and tempering of the examined cast steel ensures only the required impact strength, with mechanical properties comparable to those after service.

  5. A study on the effects of artifacts on fatigue limit of ductile cast iron with ferritic structure

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Jin Hak [Yeungnam Univ., Gyeongsan (Korea, Republic of); Kim, Min Gun [Kangwon National Univ., Chuncheon (Korea, Republic of)

    2000-10-01

    In this study, fatigue tests were performed to examine the effects of micro drill hole on fatigue limit of as cast and Austempered Ductile cast Iron (ADI) using the rotary bending fatigue tester. As results, micro drill holes (diameter{<=}0.4mm) did not influence the fatigue limit of ADI, compared to annealed ductile cast iron; the critical defect size of crack initiation, in ADI was larger than as cast. If the {radical}areas of micro drill hole and graphite nodule in ADI are comparable, crack initiates at the graphite nodule. When the ruggedness develops through austempering treatment process, microstructure on crack initiation at micro drill hole is tougher than that of as cast ductile cast iron.

  6. TECHNICAL NOTE: Spun-cast micromolding for etchless micropatterning of electrically functional PDMS structures

    Science.gov (United States)

    McClain, Maxine A.; La Placa, Michelle C.; Allen, Mark G.

    2009-10-01

    Polydimethylsiloxane (PDMS) is widely used in bioMEMS applications; however, patterning of this material to form complex structures is often challenging. Chemical etches are typically ineffective due to the inertness of the material. Plasma processing of bulk material can be time intensive and presents concerns regarding the mechanical properties of the post-etched polymer due to etch-induced cross-linking of surrounding material. Presented in this paper, the etchless process of spun-cast micromolding (SCμM) is used to create an array of patterned, PDMS, electrical microcables. The microcables are arranged in a net-like array and incorporate electrical functionality. The geometries fabricated with these techniques include straight and sinusoidal microcables. In addition to the cables themselves, specific regions of the cables' top insulating layer can also be patterned using a hierarchical application of the SCμM process, creating exposed electrical access sites useful as electrical access points for electrophysiological applications. The SCμM process is a simple, relatively rapid technique that can be used to make highly compliant electronic structures with patternable geometries.

  7. 3-D Analysis of Graphite Nodules in Ductile Cast Iron Using FIB-SEM

    DEFF Research Database (Denmark)

    D'Angelo, Luca; Jespersen, Freja N.; MacDonald, A. Nicole;

    Ductile cast iron samples were analysed in a Focused Ion Beam Scanning Electron Microscope, FIB-SEM. The focussed ion beam was used to carefully remove layers of the graphite nodules to reveal internal structures in the nodules. The sample preparation and milling procedure for sectioning graphite...

  8. Jamestown and Disneyland: Two Places in Time.

    Science.gov (United States)

    Scrofani, E. Robert; Tideman, Robert

    This unit for high school students uses two dissimilar places in time; (2) Jamestown, Virginia, founded in 1607, one of the earliest settlements in the United States and (2) Disneyland, California, built in 1956, an institution of contemporary culture. The lessons address two fundamental questions in geography: (1) where? and (2) why here rather…

  9. Metal casts showing the three-dimensional structure of the human inner ear were converted into jewelry.

    Science.gov (United States)

    Heywood, Peter

    2015-06-01

    This article describes a straightforward method for making metal casts of the human inner ear developed in 1937 by M. Wharton Young of Howard University College of Medicine. These casts were used to study anatomy, but there do not appear to be any published photographs of the casts. Inner ear casts converted into jewelry provide the only known images of this work. Later, Young studied the inner ear in living rhesus monkeys by injecting mercury into their membranous labyrinths. Young's investigations indicated a blind-ending perilymphatic sac that was not in continuity with the subarachnoid space.

  10. Mechanisms regulating caste differentiation in an aphid social system.

    Science.gov (United States)

    Shibao, Harunobu; Kutsukake, Mayako; Matsuyama, Shigeru; Fukatsu, Takema; Shimada, Masakazu

    2010-01-01

    For evolution and maintenance of the social systems of insect colonies, caste production should be controlled in response to external cues so that caste ratio in the colony is kept at an optimal range. Recent developments using artificial diet rearing techniques have revealed an underlying mechanism for adaptive control of caste production in a social aphid, Tuberaphis styraci, which has a sterile soldier caste in the 2(nd) instar. Aphid density was the proximate cue that acts on 1(st) instar nymphs and embryos to induce soldier differentiation. The final determination of soldier differentiation occurred postnatally, probably at a late 1(st) instar stage. Direct contact stimuli from live non-soldier aphids mediated the density effect. While coexisting non-soldiers facilitated soldier differentiation in 1(st) instar nymphs, coexisting soldiers acted to suppress such differentiation. These results suggest that caste production in aphid colonies is controlled by positive and negative feedback mechanisms consisting of density-dependent induction and suppression of soldier differentiation. Here, we demonstrate the mechanisms that coordinate aphid society, and provide a striking case of clonal superorganism system where simple responses of colony members to local extrinsic stimuli are integrated into a highly organized regulation of the whole colony.

  11. Green electricity in the market place revisited

    NARCIS (Netherlands)

    Arentsen, Maarten J.; Fuchs, Doris; Brunnengräber, Achim; Di Nucci, Maria Rosaria

    2014-01-01

    In 2002, we published a paper in Energy Policy under the title: Green electricity in the market place: the policy challenge (Fuchs & Arentsen 2002). In that paper, we used a co-evolutionary approach to show the extent to which producers and consumers were locked into technological and institutional

  12. A space imaging concept based on a 4m structured spun-cast borosilicate monolithic primary mirror

    Science.gov (United States)

    West, S. C.; Bailey, S. H.; Bauman, S.; Cuerden, B.; Granger, Z.; Olbert, B. H.

    2010-07-01

    Lockheed Martin Corporation (LMC) tasked The University of Arizona Steward Observatory (UASO) to conduct an engineering study to examine the feasibility of creating a 4m space telescope based on mature borosilicate technology developed at the UASO for ground-based telescopes. UASO has completed this study and concluded that existing launch vehicles can deliver a 4m monolithic telescope system to a 500 km circular orbit and provide reliable imagery at NIIRS 7-8. An analysis of such an imager based on a lightweight, high-performance, structured 4m primary mirror cast from borosilicate glass is described. The relatively high CTE of this glass is used to advantage by maintaining mirror shape quality with a thermal figuring method. Placed in a 290 K thermal shroud (similar to the Hubble Space Telescope), the orbit averaged figure surface error is 6nm rms when earth-looking. Space-looking optical performance shows that a similar thermal conditioning scheme combined with a 270 K shroud achieves primary mirror distortion of 10 nm rms surface. Analysis shows that a 3-point bipod mount will provide launch survivability with ample margin. The primary mirror naturally maintains its shape at 1g allowing excellent end-to-end pre-launch testing with e.g. the LOTIS 6.5m Collimator. The telescope includes simple systems to measure and correct mirror shape and alignment errors incorporating technologies already proven on the LOTIS Collimator. We have sketched a notional earth-looking 4m telescope concept combined with a wide field TMA concept into a DELTA IV or ATLAS 552 EELV fairing. We have combined an initial analysis of launch and space performance of a special light-weighted honeycomb borosilicate mirror (areal density 95 kg/m2) with public domain information on the existing launch vehicles.

  13. Modelling of Filling, Microstructure Formation, Local Mechanical Properties and Stress – Strain Development in High-Pressure Die Cast Aluminium Castings

    DEFF Research Database (Denmark)

    Kotas, Petr; Hattel, Jesper Henri; Thorborg, Jesper

    2009-01-01

    inherently affects the component’s properties depending on design, metallurgy and casting technique. The wall thickness influences the coarseness of the microstructure and the material will have properties depending on the local metallurgical and thermal histories. This is independent on the material, i.......e. whether the casting is based on cast iron- or aluminium-alloys. The distribution of local properties in a casting might vary substantially which makes it complex to optimize the casting with good accuracy. Often, mechanical simulations of the load situation are based on the assumption that the cast...... product has constant material properties throughout the entire casting. Thus, if the microstructure is determined or predicted at a given point, it gives the possibility to calculate the local material behavior more realistically. In the present work, a test case of a complex high-pressure die cast part...

  14. Characterisation and modelling of defect formation in direct-chill cast AZ80 alloy

    Energy Technology Data Exchange (ETDEWEB)

    Mackie, D.; Robson, J.D.; Withers, P.J. [School of Materials, University of Manchester, Manchester M13 9PL (United Kingdom); Turski, M. [Magnesium Elektron UK, Rake Lane, Manchester, M27 8BF (United Kingdom)

    2015-06-15

    Wrought magnesium alloys for demanding structural applications require high quality defect free cast feedstock. The aim of this study was to first identify and characterise typical defects in direct chill cast magnesium–aluminium–zinc (AZ) alloy billet and then use modelling to understand the origins of these defects so they can be prevented. Defects were first located using ultrasonic inspection and were then characterised using X-ray computed tomography (XCT) and serial sectioning, establishing the presence of oxide films and intermetallic particles Al{sub 8}Mn{sub 5} in all defects. A model was developed to predict the flow patterns and growth kinetics of the intermetallic phases during casting, which influence the formation of defects. Simulation of the growth of the intermetallic particles demonstrated that precipitation from the liquid occurs in the mould. The combination of the entrained oxide films and intermetallic particles recirculates in the liquid metal and continues to grow, until large enough to settle, which is predicted to occur at the centre of the mould where the flow is the slowest. Based on these predictions, strategies to reduce the susceptibility to defect formation are suggested. - Highlights: • Casting defects in magnesium direct chill casting have been imaged and characterised in 3-dimensions. • The occurrences of co-located clusters of particles and oxide films have been characterised and explained. • A coupled model has been developed to help interpret the observed trend for defects located towards the centre of billets.

  15. Ageing in Place Driving Urban Transformations

    Directory of Open Access Journals (Sweden)

    Marta Kavšek

    2016-03-01

    Full Text Available Abstract Research question: This article provides an answer to the question: What kind of housing do the seniors in Slovenia prefer after a substantial decrease of their functional capacities, i.e. when they already need long-term care services? Purpose: During the study, the seniors participating in the study were still able to live in their current dwelling – in the home where they lived for years together with their family or alone; but because of a substantial decrease of their functional capacities they had become aware that it would be difficult to continue to stay there. We wanted to know where they would like to migrate or move to when needed, and what kind of housing should be provided on the housing market for these cohorts. Method: After our study of the relevant European and American literature we found that the construction of housing for seniors can be developed in different types of structures and that there is a substantial gap between the needs and the availabilities of housing arrangements in Slovenia, which also increases the rigidity of the Slovenian housing market and reduces land rent in comparison with USA and Western Europe. Seniors using long-term care services provided by municipalities in their own homes, living outside the main Slovenian central places, were included in the survey. To identify the preferred structure of the built environment for seniors we organised 3 groups of interviews with assisted living inhabitants from three Slovenian municipalities and evaluated the percentages of each desired type of housing and care. Results: The results show that more than half of Slovenian seniors do not have the possibility to move to retirement villages or other better adapted homes in assisted living housing units, where they could protect their dignity and independence better than in institutional care in nursing homes. Local administration and society: These findings refer to the local administration initiative to

  16. Chemical Agents: Facts about Sheltering in Place

    Science.gov (United States)

    ... Store 1 gallon of water per person in plastic bottles as well as ready-to-eat foods that will keep without refrigeration in the shelter-in-place room. If you do not have bottled water, or if ... and plastic sheeting. You may wish to cut your plastic ...

  17. The metaphor in the Changing Place

    Institute of Scientific and Technical Information of China (English)

    李晨

    2013-01-01

    This paper attempts to use some basic principles in the modern metaphor theory in the cognitive theory to analyze the Changing Place, which is one of the representatives of David Lodge’s academic fictions, so that it can help to have a better understanding of the metaphor used in this fiction.

  18. Electromagnetic stirring in the continuous casting of steel. Agitacion electromagnetica en la colada continua de acero

    Energy Technology Data Exchange (ETDEWEB)

    Alvarez de Toledo, G.; Campo, O.; Lainez, E. (Sidenor, Basauri (Spain))

    1995-01-01

    The electromagnetic stirring of steel in the machines for the continuous casting process has improved the internal quality of the cast product. Experimental work with stirrers situated at different positions of continuous casting machines of billets has been carried out. The in-mould stirrer is the one that produces a major modification of the billet internal structure, and also the biggest decrease of the central segregation. An in mould electromagnetic coil has been developed which allows the use of high stirring power without producing an undesirable movement of the liquid steel in the meniscus zone, therefore no mould powders entrapments are produced. It has been developed a method for determining the optimum electric frequency of the stirrer. (Author) 31 refs.

  19. Crystallization and structure of cast A390.0 alloy with melt overheating temperature

    Directory of Open Access Journals (Sweden)

    J. Piątkowski

    2012-07-01

    Full Text Available The paper presents the research on the influence of melt overheating temperature on crystallization parameters and primary structure of cast AlSi17Cu5Mg (A390.0 alloy overheated to temperature: 820 °C, 880 °C, 940 °C and 1 000 °C. It was found that the degree of overheating influences the change of microstructure significantly and morphologies of primary silicon of the castings from Al-Si alloys. Research has shown that the overheating of the liquid metal bath is one of the methods of finding more applications of hypereutectic Al-Si system alloys without the addition of modifiers.

  20. Awareness Programs and Change in Taste-based Caste Prejudice

    DEFF Research Database (Denmark)

    Banerjee, Ritwik; Gupta, Nabanita Datta

    2015-01-01

    Becker's theory of taste-based discrimination predicts that relative employment of the discriminated social group will improve if there is a decrease in the level of prejudice for the marginally discriminating employer. In this paper we experimentally test this prediction offered by Garry Becker...... in his seminal work on taste based discrimination, in the context of caste in India, with management students (potential employers in the near future) as subjects. First, we measure caste prejudice and show that awareness through a TV social program reduces implicit prejudice against the lower caste...... and the reduction is sustained over time. Second, we find that the treatment reduces the prejudice levels of those in the left tail of the prejudice distribution - the group which can potentially affect real outcomes as predicted by the theory. And finally, a larger share of the treatment group subjects exhibit...

  1. Dataset on outdoor behavior-system and spatial-pattern in the third place in cold area-based on the perspective of new energy structure

    Directory of Open Access Journals (Sweden)

    Kai Ren

    2017-02-01

    Full Text Available The data presented in this paper are related to the research article entitled “Exploration of Outdoor Behavior System and Spatial Pattern in the Third Place in Cold Area- based on the perspective of new energy structure” (Ren, 2016 [1]. The dataset was from a field sub-time extended investigation to residents of Power Home Community in Inner Mongolia of China that belongs to cold region of ID area according to Chinese design code for buildings. This filed data provided descriptive statistics about environment-behavior symbiosis system, environment loading, behavior system, spatial demanding and spatial pattern for all kinds of residents (Older, younger, children. The field data set is made publicly available to enable critical or extended analyzes.

  2. Market design in Chinese market places

    NARCIS (Netherlands)

    B. Krug (Barbara); H. Hendrischke (Hans)

    2012-01-01

    textabstractThe market design (MD) approach to institutional analysis provides the analytical tools to evaluate endogenous institution building in local market places irrespective of the institutional setting of the national economy. Implicit in this analysis of endogenous institution building at th

  3. Market Design in Chinese Market Places

    NARCIS (Netherlands)

    B. Krug (Barbara); H. Hendrischke (Hans)

    2012-01-01

    textabstractThe Market Design (MD) approach to institutional analysis provides the analytical tools to evaluate endogenous institution building in local market places irrespective of the institutional setting of the national economy. Implicit in this analysis of endogenous institution building at th

  4. Audio in Place

    DEFF Research Database (Denmark)

    Chamberlain, Alan; Bødker, Mads; Hazzard, Adrian

    2016-01-01

    experience in the world. Vision, and to some extent the tactile senses have been dominant modalities discussed in experiential terms within HCI. This workshop suggests that there is a need to better understand how sound can be used for shaping and augmenting the experiential qualities of places through...

  5. 大跨度现浇预应力空心楼板结构设计%Structure design of Large Span cast-in-situ pre-stressed hollow lfoor slab

    Institute of Scientific and Technical Information of China (English)

    赵燕; 寇栩霆; 刘英达

    2015-01-01

    包头市“正翔国际”二期商业IMAX影厅工程,采用了大跨度现浇预应力空心楼板,通过分析结构实际的受力状态,拟定了结构在设计时需要采取的技术措施、设计要求及施工工艺,并对结构计算与构造进行了介绍,对于大跨度预应力空心板设计中可能遇到的问题进行了有益的探索。%The "zhengxiang" international business IMAX screens projectphase iiBaotou used a large span pre-stressed hol ow slab cast.By analyzing the structure of the actual stress state, technical measures and design requirements and construction technology have be taken in the design of the structure. Calculation and construction of the structure are introduced and useful exploration has be conducted of long-span pre-stressed hol ow problems.

  6. Use of SEM and EDS analysis in the investigation of Al-Si-Cu piston alloy cast porosity

    Directory of Open Access Journals (Sweden)

    D. Kakaš

    2009-07-01

    Full Text Available Porosity formation was detected in the casting thinnest section in the proximity of the as cast surface and near the wall centerline. In order to investigate the cause of the porosity formation light microscopy was used to define as cast structure. After initial findings SEM and EDS analyses were performed. Based on the results it is possible to define cause of the observed porosity. A number of pores originates from the mould filling stage and entrainment of the oxide films, while others appear due to insufficient feeding during solidification.

  7. Castes, migration, immunogenetics and infectious diseases in south India.

    Science.gov (United States)

    Pitchappan, R M

    2002-01-01

    It has been said that the grandest genetic experiment of nature has been conducted in south India in the name of the caste system. One can expect the frequency of an infectious disease to be equal to the product of the frequencies of various indicated loci/alleles, whether physiological, hormonal or immunological, in an endemic area. The sympatrically isolated caste and sub-caste populations of southern India, with differing origins, migration patterns and breeding habits, differ significantly in their HLA and other immune repertoire and are ideal models to study and test this hypothesis. The prevalence of a number of major infectious diseases, including TB and leprosy, are reviewed in different communities in the light of their genetic history.

  8. High Density Die Casting (HDDC): new frontiers in the manufacturing of heat sinks

    Science.gov (United States)

    Sce, Andrea; Caporale, Lorenzo

    2014-07-01

    Finding a good solution for thermal management problems is every day more complex. due to the power density and the required performances. When a solution suitable for high volumes is needed. die-casting and extrusion are the most convenient technologies. However designers have to face the well-known limitations for those processes. High Density Die Casting (HDDC) is a process under advanced development. in order to overcome the extrusion and traditional die casting limits by working with alloys having much better thermal performances than the traditional die-casting process. while keeping the advantages of a flexible 3D design and a low cost for high volumes. HDDC offers the opportunity to design combining different materials (aluminium and copper. aluminium and stainless steel) obtaining a structure with zero porosity and overcoming some of die-casting limits. as shown in this paper. A dedicated process involving embedded heat pipes is currently under development in order to offer the possibility to dramatically improve the heat spreading.

  9. The effect of equipment efficiency on occurrence of non-conforming products in die casting

    Directory of Open Access Journals (Sweden)

    S. Borkowski

    2010-01-01

    Full Text Available This study focuses on determination of the relationships between equipment efficiency in casting machines and the level of quality. The determination was made based on coefficients of Total Productive Maintenance and r correlation coefficient. The degree at which break-downs and downtime affect the occurrence of non-conforming products was also evaluated. The goal of further investigations is to deter-mine the structure of downtime and finding which downtime types have greatest impact on the quality of die-casting products.

  10. Influence of solvent polarity on the structure of drop-cast electroactive tetra(aniline)-surfactant thin films.

    Science.gov (United States)

    Dane, Thomas G; Bartenstein, Julia E; Sironi, Beatrice; Mills, Benjamin M; Alexander Bell, O; Emyr Macdonald, J; Arnold, Thomas; Faul, Charl F J; Briscoe, Wuge H

    2016-09-21

    The influence of processing conditions on the thin film microstructure is a fundamental question that must be understood to improve the performance of solution-processed organic electronic materials. Using grazing-incidence X-ray diffraction, we have studied the structure of thin films of a tetra(aniline)-surfactant complex prepared by drop-casting from five solvents (hexane, chloroform, tetrahydrofuran, dichloromethane and ethanol), selected to cover a range of polarities. We found that the structure, level of order and degree of orientation relative to the substrate were extremely sensitive to the solvent used. We have attempted to correlate such solvent sensitivity with a variety of solvent physical parameters. Of particular significance is the observation of a sharp structural transition in the thin films cast from more polar solvents; such films presented significantly greater crystallinity as measured by the coherence length and paracrystalline disorder parameter. We attribute this higher structural order to enhanced dissociation of the acid surfactant in the more polar solvents, which in turn promotes complex formation. Furthermore, the more polar solvents provide more effective screening of (i) the attractive ionic interaction between oppositely charged molecules, providing greater opportunity for dynamic reorganisation of the supramolecular aggregates into more perfect structures; and (ii) the repulsive interaction between the positively charged blocks permitting a solvophobic-driven aggregation of the aromatic surfaces during solvent evaporation.

  11. The Bay in Place of a Glacier.

    Science.gov (United States)

    Howell, Wayne

    1997-01-01

    The cultural resource specialist at Glacier Bay National Park (Alaska) explains the collaborative efforts of park staff and the Hoonah Tlingit to overcome language and cultural barriers in documenting park place names and clan oral history and traditions. The new park-community relationship, which follows decades of conflict, includes training…

  12. Placing Teachers in Global Governance Agendas

    Science.gov (United States)

    Robertson, Susan L.

    2012-01-01

    This article examines the focus on teacher policies and practices by a range of global actors and explores their meaning for the governance of teachers. Through a historical and contemporary reading, I argue that an important shift in the locus of power to govern has taken place. I show how the mechanisms of global governance of teachers are being…

  13. EFFECT OF ALLOYING ON TEMPERATURE OF TRANSFORMATION «PEARLITE – AUSTENITE» IN COMPLEX-ALLOYED WHITE CAST IRONS

    OpenAIRE

    2014-01-01

    Purpose. Pearlite is not accepted in the microstructure of wear resistant steels and cast irons. To prevent the pearlite by means of appropriate selection of mode of quenching requires the knowledge of the temperature of the critical points Ac1 and Ac3 for various steels and cast irons. Purpose of work is determine the effect of V (5-10%) and Cr (up to 9%) on the temperature range of the phase-structural transformation "pearlite®austenite in the complex-alloyed V-Cr-Mn-Ni white cast irons wit...

  14. Effects of slope plate variable and reheating on semi-solid structure of reheating on semi-solid structure of ductile cast iron

    Directory of Open Access Journals (Sweden)

    M. Nili-Ahmadabadi

    2008-02-01

    Full Text Available Semi-solid metal casting and forming are known as a promising process for a wide range of metal alloys production. In spite of growing application of semi-solid processed light alloys, a few works have been reported about semi-solid processing of iron and steel. In this research inclined plate was used to change dendritic structure of iron to globular one. The effects of length and slope of plate on the casting structure were examined. The results show that the process can effectively change the dendritic structure to globular. In the slope plate angle of 7.5° and length of 560 mm with cooling rate of 67Ks-1 the optimum nodular graphite and solid globular particle were achieved.The results also show that by using slope plate inoculant fading can be prevented more easily since the total time of process is rather short. In addition, the semi-solid ductile cast iron prepared by inclined plate method, was reheated to examine the effect of reheating conditions on the microstructure and coarsening kinetics of the alloy. Solid fraction at different reheating temperatures and holding time was obtained and based on these results the optimum reheating temperature range was determined.

  15. Numerical Analysis of Secondary Cooling in Continuous Slab Casting

    Institute of Scientific and Technical Information of China (English)

    Kee-Hyeon Cho; Byung-Moon Kim

    2008-01-01

    In the present study, a numerical optimization program has been developed for predicting the optimal secondary cooling patterns in a continuous slab caster. Optimization strategy using Broydon-Fletcher-Goldfarb-Shanno (BFGS) method is carried out by determining the constant heat transfer coefficients in each spray zone, which could satisfy the casting conditions and metallurgical criteria specified by the engineer. From the present results, it is found that even a slight variation in the pouring temperature, allowable surface temperature, and casting speed could give rise to the changes in the cooling pattern throughout the spray zones.

  16. Theory of uniqueness of Indian Caste System

    OpenAIRE

    Kumar, Ashwin

    2006-01-01

    Classical studies on pre-modern Indian social structure have suggested apparent differences between the Indian caste system and social stratification as one can discern in other parts of the world. However, one needs to question such dogmatic assertions that such vast differences really existed. An endeavor is made in this research paper to reflect on the nature of caste hierarchy in pre-modern India. The caste system forms the significant basis of pre-modern Indian social structure. Early wr...

  17. Social Organization in Parasitic Flatworms--Four Additional Echinostomoid Trematodes Have a Soldier Caste and One Does Not.

    Science.gov (United States)

    Garcia-Vedrenne, Ana E; Quintana, Anastasia C E; DeRogatis, Andrea M; Martyn, Kayla; Kuris, Armand M; Hechinger, Ryan F

    2016-02-01

    Complex societies where individuals exhibit division of labor with physical polymorphism, behavioral specialization, and caste formation have evolved several times throughout the animal kingdom. Recently, such complex sociality has been recognized in digenean trematodes; evidence is limited to 6 marine species. Hence, the extent to which a soldier caste is present throughout the Trematoda is sparsely documented, and there are no studies detailing the structure of a species lacking such a social structure. Here we examine colony structure for an additional 5 echinostomoid species, 4 of which infect the marine snail Cerithidea californica and 1 (Echinostoma liei) that infects the freshwater snail Biomphalaria glabrata . For all species, we present redia morphology (pharynx and body size) and the distribution of individuals of different castes throughout the snail body. When morphological evidence indicated the presence of a soldier caste, we assessed behavior by measuring attack rates of the different morphs toward heterospecific trematodes. Our findings indicate that each of the 4 species from C. californica have a permanent soldier caste while E. liei does not. The observed intra- and inter-specific variation of caste structure for those species with soldiers, and the documentation of colony structure for a species explicitly lacking permanent soldiers, emphasizes the diverse nature of trematode sociality and the promise of the group to permit comparative investigations of the evolution and ecology of sociality.

  18. 现浇砼聚苯乙烯BDF柱体施工%The Cast-in-situ Concrete Polystyrene BDF Column Construction

    Institute of Scientific and Technical Information of China (English)

    范海军; 范佳波

    2012-01-01

      现浇混凝土空心楼盖技术是建筑结构领域的一项创新,符合人类的高技术水平的建筑结构体系。本文根据瑞景国际地下车库现浇砼空心楼盖工程对施工现场的管理、BDF 聚苯轻质柱体质量要求和施工技术进行阐述,为类似现浇混凝土空心楼盖施工提供技术参考。%  Cast-in-situ concrete hol ow floor system technol-ogy is an innovation in the field of building structure. It is in line with the human high technology of building structure system.In this paper, the author elaborates construction site management,quality requirements of the BDF polystyrene light column and construction technology about cast-in-situ concre-te hol ow floor engineering of the vista international underg-round garage, in order to provide technical reference for sim-ilar cast-in-place concrete hol ow floor construction.

  19. Determining the optimal index of heat stress in foundry, die casting and road construction industries using FAHP_Topsis

    Directory of Open Access Journals (Sweden)

    Maryam Dehghanipoor

    2016-12-01

    Full Text Available Introduction: Heat stress is one of the harmful risks in casting and die casting industries, which can not only cause work-related diseases but also can impair the performance and safety of workers. Since the indicators that are used to evaluate heat stress are very different, it is very difficult to choose a suitable index. The aim of this study was to determine the optimum heat stress index in foundry, die-cast, and road construction industries using FAHP and Topsis methods. Material and Method: In order to determine optimum heat stress index in foundry, die-cast, and road construction industries, first, the prioritization criteria were defined by experts (including ease of measurement, measurement accuracy, comprehensiveness, time, cost, and correlation. Then, considering these criteria, the best heat stress index was determined based on experts’ opinions and using FAHP and Topsis methods. Result: The results of this study suggest that given the current conditions and criteria, WBGT and P4SR is the best indices for foundry, die casting and construction. Conclusion: The results showed that according to comprehensiveness, accuracy and correlation criteria, the WBGT index is considered as the best indicator of heat stress assessment in foundry, die-cast and road construction industries. Moreover, the HSI ranked in the last place due to the complexity and cost of its calculation.

  20. Correlation between macroscopic porosity location and liquid metal pressure in centrifugal casting technique.

    Science.gov (United States)

    Vaidyanathan, T K; Schulman, A; Nielsen, J P; Shalita, S

    1981-01-01

    Radiographic analysis of uniform cylindrical castings fabricated by the centrifugal casting technique has revealed that the macroscopic porosity is dependent on the location of the sprue attachment to the casting. This is attributed to the significant pressure gradient associated with the centrifugal casting technique. The pressure gradient results in different heat transfer rates at portions of the castings near and away from the free surface of the button. Consequently, the macroscopic porosity is invariably at portions of the casting close to the free surface of the button. In addition, some optimized sprue-reservoir combinations could be predicted and proved, based on this pressure gradient concept.

  1. Improvement of die life in high speed injection die casting

    Institute of Scientific and Technical Information of China (English)

    Yasuhiro Arisuda; Akihito Hasuno; Junji Yoshida; Kazunari Tanii

    2008-01-01

    High-speed injection die casting is an efficient manufacturing technology for upgrading aluminum die-cast products. However, deficiencies (such as die damage in eady period) due to larger load on the molding die compared with conventional technology have brought new challenges. In this study, the cause of damage generated in super high-speed injection was investigated by the combination of experimental observation of the dies and CAE simulation (e.g. die temperature analysis, flow analysis and thermal stress analysis). The potential countermeasures to solve the above problems were also proposed.

  2. Improvement of die life in high speed injection die casting

    Directory of Open Access Journals (Sweden)

    Akihito Hasuno

    2008-11-01

    Full Text Available High-speed injection die casting is an effi cient manufacturing technology for upgrading aluminum die-cast products. However, defi ciencies (such as die damage in early period due to larger load on the molding die compared with conventional technology have brought new challenges. In this study, the cause of damage generated in super high-speed injection was investigated by the combination of experimental observation of the dies and CAE simulation (e.g. die emperature analysis, fl ow analysis and thermal stress analysis. The potential countermeasures to solve the above problems were also proposed.

  3. Changing Relations between High Castes and Tamang in Melamchi Valley

    Directory of Open Access Journals (Sweden)

    Binod Pokharel

    2011-04-01

    Full Text Available This paper is about the processes of transformation of social relations between high caste groups and Tamang in Melamchi Valley for the period of 1980-2010. Development interventions made by government of Nepal and (I NGOs, a decade long undergoing Melamchi Water Supply Project and labor migration are major factors for ongoing changes in the study area. Spread of literacy classes and primary education, availability of credit institutions, introduction of modern farming, road networks, seasonal out migration from the area, etc. primarily define new relations among the groups. Borrowing and lending money were one of the basis of high caste and Tamang relation in past. The latter was regarded as borrower loan from first one. Before 1980s, money and agriculture commodities were controlled by few rich and high castes people. Cash income from various sources made enable the Tamang to stand on an equal footing with high caste people. Open political economy and liberal policy for issuing pass port in 1990s and after that encourage the people to diversify the destination of seasonal migration from India to Gulf countries and East Asia. Various processes of socio-economic and political changes led to local peoples to seek their position and identity in the changing context. Discourse of Tamang, high castes and Dalit entered into the Valley along with the development resources of (INGO and political movements of the country. This made possible to Tamang and other disadvantage groups to define and redefine their ethnic identity. Keywords: High castes; Tamang; credit facilities; subsistence farming; identity construction; money lending; wage labor DOI: 10.3126/dsaj.v4i0.4513 Dhaulagiri Journal of Sociology and Anthropology Vol.4 2010 pp.65-84

  4. Effect of cast-in-situ floor slab on collapse modes of RC frame structures under earthquake%现浇楼板对钢筋混凝土框架结构倒塌模式的影响

    Institute of Scientific and Technical Information of China (English)

    汪小林; 顾祥林; 印小晶; 黄庆华

    2013-01-01

    地震作用下钢筋混凝土框架结构通常呈现弱柱型破坏模式而倒塌.针对其破坏特征,将钢筋混凝土框架结构离散为“板-柱”和“梁-柱-节点”体系,结合块体间碰撞作用的冲量模型,基于离散单元法建立考虑构件间碰撞作用的钢筋混凝土框架结构空间倒塌反应计算机仿真系统,并通过2个框架结构模型的倒塌试验对其进行了验证.利用计算机仿真系统模拟分析了现浇楼板对钢筋混凝土框架结构倒塌模式的影响.结果表明:考虑块体间碰撞作用的框架结构倒塌仿真系统可以真实再现地震作用下框架结构的倒塌过程和废墟堆积情况;考虑楼板影响时,强柱型框架结构可能会出现弱柱型倒塌,局部倒塌型框架结构则可能不倒或呈弱柱型倒塌;框架结构抗震设计或评定中应充分考虑现浇楼板对框架抗震性能的影响.%RC frame structures severely damaged, even collapsed in weak column mode were well documented during the past post-earthquake investigations. A collapse simulation system for RC frame structures based on discrete element method was established by discretizing a structure into slab-column discrete system or beam-column-joint discrete system according to the failure characteristic of RC frame structures, and revised with consideration of collision behaviors among fractured components with impulse-based impact model between concrete blocks. The proposed collapse simulation system was effectively verified with two collapse experiments on small-scale frame models. Further simulation was carried out to explore the effect of cast-in-situ floor slab on the collapse performance of RC frame structures under earthquake. The results indicate that, the whole collapse process of a frame structure including debris stacking can be visually simulated by the collapse simulation system with consideration of collision actions among fractured components; due to the effect of cast-in

  5. A Tale Begun in Other Days: Understanding Caste as Social Exclusion in India

    OpenAIRE

    Negi, Prashant

    2011-01-01

    Caste has remained a subject of intense academic inquiry. Lately, new discourses have emerged under the thematic of ‘social exclusion’ that simply extend the scope of academic discussion on caste. This paper assumes that such discourses are relatively less applied to understanding the caste system and for the same attempts to juxtapose thinking on social exclusion to understanding caste in India. Thematically, these methodological issues are dealt with by firstly, presenting a brief backgrou...

  6. The forty years of vermicular graphite cast iron development in China (Part Ⅲ

    Directory of Open Access Journals (Sweden)

    QIU han-quan

    2007-11-01

    Full Text Available In China, the research and development of vermicular graphite cast iron (VGCI as a new type of engineering material, were started in the same period as in other developed countries; however, its actual industrial application was even earlier. In China, the deep and intensive studies on VGCI began as early as the 1960s. According to the incomplete statistics to date, more than 600 papers on VGCI have been published by Chinese researchers and scholars at national and international conferences, and in technical journals. More than ten types of production methods and more than thirty types of treatment alloy have been studied. Formulae for calculating the critical addition of treatment alloy required to produce VGCI have been put forward, and mechanisms for explaining the formation of dross during treatment were brought forward. The casting properties, metallographic structure, mechanical and physical properties and machining performance of VGCI, as well as the relationships between them, have all been studied in detail. The Chinese Standards for VGCI and VGCI metallographic structure have been issued. In China, the primary crystallization of VGCI has been studied by many researchers and scholars. The properties of VGCI can be improved by heat treatment and addition of alloying elements enabling its applications to be further expanded. Hundreds of kinds of VGCI castings have been produced and used in vehicles, engines, mining equipment, metallurgical products serviced under alternating thermal load, machinery, hydraulic components, textile machine parts and military applications. The heaviest VGCI casting produced is 38 tons and the lightest is only 1 kg. Currently, the annual production of the VGCI in China is about 200 000 tons. The majority of castings are made from cupola iron without pre-treatment, however, they are also produced from electric furnaces and by duplex melting from cupolaelectric furnaces or blast furnace-electric furnace

  7. The forty years of vermicular graphite cast iron development in China (Part 2

    Directory of Open Access Journals (Sweden)

    CHEN Zheng-de

    2007-08-01

    Full Text Available In China, the research and development of vermicular graphite cast iron (VGCI as a new type of engineering material, were started in the same period as in other developed countries; however, its actual industrial application was even earlier. In China, the deep and intensive studies on VGCI began as early as the 1960s. According to the incomplete statistics to date, more than 600 papers on VGCI have been published by Chinese researchers and scholars at national and international conferences, and in technical journals. More than ten types of production methods and more than thirty types of treatment alloy have been studied. Formulae for calculating the critical addition of treatment alloy required to produce VGCI have been put forward, and mechanisms for explaining the formation of dross during treatment were brought forward. The casting properties, metallographic structure, mechanical and physical properties and machining performance of VGCI, as well as the relationships between them, have all been studied in detail. The Chinese Standards for VGCI and VGCI metallographic structure have been issued. In China, the primary crystallization of VGCI has been studied by many researchers and scholars. The properties of VGCI can be improved by heat treatment and addition of alloying elements enabling its applications to be further expanded. Hundreds of kinds of VGCI castings have been produced and used in vehicles, engines, mining equipment, metallurgical products serviced under alternating thermal load, machinery, hydraulic components, textile machine parts and military applications. The heaviest VGCI casting produced is 38 tons and the lightest is only 1 kg. Currently, the annual production of the VGCI in China is about 200 000 tons. The majority of castings are made from cupola iron without pre-treatment, however, they are also produced from electric furnaces and by duplex melting from cupolaelectric furnaces or blast furnace-electric furnace

  8. The forty years of vermicular graphite cast iron development in China (PartⅠ

    Directory of Open Access Journals (Sweden)

    CHEN Zheng-de

    2007-05-01

    Full Text Available In China, the research and development of vermicular graphite cast iron (VGCI as a new type of engineering material, were started in the same period as in other developed countries; however, its actual industrial application was even earlier. In China, the deep and intensive studies on VGCI began as early as the 1960s. According to the incomplete statistics to date, more than 600 papers on VGCI have been published by Chinese researchers and scholars at national and international conferences, and in technical journals. More than ten types of production methods and more than thirty types of treatment alloy have been studied. Formulae for calculating the critical addition of treatment alloy required to produce VGCI have been put forward, and mechanisms for explaining the formation of dross during treatment were brought forward. The casting properties, metallographic structure, mechanical and physical properties and machining performance of VGCI, as well as the relationships between them, have all been studied in detail. The Chinese Standards for VGCI and VGCI metallographic structure have been issued. In China, the primary crystallization of VGCI has been studied by many researchers and scholars. The properties of VGCI can be improved by heat treatment and addition of alloying elements enabling its applications to be further expanded. Hundreds of kinds of VGCI castings have been produced and used in vehicles, engines, mining equipment, metallurgical products serviced under alternating thermal load, machinery, hydraulic components, textile machine parts and military applications. The heaviest VGCI casting produced is 38 tons and the lightest is only 1 kg. Currently, the annual production of the VGCI in China is about 200 000 tons. The majority of castings are made from cupola iron without pre-treatment, however, they are also produced from electric furnaces and by duplex melting from cupolaelectric furnaces or blast furnace-electric furnace

  9. The forty years of vermicular graphite cast iron development in China

    Institute of Scientific and Technical Information of China (English)

    QIU han-quan; CHEN Zheng-de

    2007-01-01

    In China, the research and development of vermicular graphite cast iron (VGCI) as a new type of engineering material, were started in the same period as in other developed countries; however, its actual industrial application was even earlier. In China, the deep and intensive studies on VGCI began as early as the 1960s. According to the incomplete statistics to date, more than 600 papers on VGCI have been published by Chinese researchers and scholars at national and international conferences, and in technical journals. More than ten types of production methods and more than thirty types of treatment alloy have been studied. Formulae for calculating the critical addition of treatment alloy required to produce VGCI have been put forward, and mechanisms for explaining the formation of dross during treatment were brought forward. The casting properties, metallographic structure, mechanical and physical properties and machining performance of VGCI, as well as the relationships between them, have all been studied in detail. The Chinese Standards for VGCI and VGCI metallographic structure have been issued. In China, the primary crystallization of VGCI has been studied by many researchers and scholars. The properties of VGCI can be improved by heat treatment and addition of alloying elements enabling its applications to be further expanded. Hundreds of kinds of VGCI castings have been produced and used in vehicles, engines,mining equipment, metallurgical products serviced under alternating thermal load, machinery, hydraulic components, textile machine parts and military applications. The heaviest VGCI casting produced is 38 tons and the lightest is only 1 kg.Currently, the annual production of the VGCI in China is about 200 000 tons. The majority of castings are made from cupola iron without pre-treatment, however, they are also produced from electric furnaces and by duplex melting from cupolaelectric furnaces or blast furnace-electric furnace. Examples of typical

  10. PHASE STRUCTURE AND COMPATIBILITY OF LADDERLIKE POLYPHENYLSILSESQUIOXANE (PPSQ)/POLYCARBONATE (PC) BLENDS PREPARED BY SOLUTION CASTING

    Institute of Scientific and Technical Information of China (English)

    Gui-zhi Li; Liang-he Shi

    1999-01-01

    Blends of PC and PPSQ (A) with high Mw and good ladderlike regularity or PPSQ(B) with low Mw and more defective Si-atoms in its structure have been prepared by solution casting. The dispersed spheres (PPSQ(A)-rich) are unevenly dispersed in the continuous PC-rich phase and there is no phase-inversion as PPSQ(A) content increases when the percentage of PPSQ(A) is not more than70%. PPSQ(B)-rich spheres are evenly dispersed in the continuous phase (PC-rich) and phaseinversion occurs when PPSQ(B) percentage is up to 70%. Tg of PPSQ(A)/PC or PPSQ(B)/PC at some compositions are lower than that of pure PC due to the enlarged free-volume of PC-rich phase because some spheres of rigid PPSQ chains are included in the PC-rich phase. PC and PPSQ(A) or PPSQ(B)are partially compatible. The compatibility of PC and PPSQ(B) is better than that of PC and PPSQ(A)with high Mw and good ladderlike regularity. Heat history has some influence on the TgS and compatibility of PPSQ(A)/PC and PPSQ(B)/PC blends.

  11. Award-Winning Castings and Enterprises in "High Quality Casting Appraisement" at the 6th International Non-Ferrous & Special Casting Exhibition (China)

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    @@ The International Non-ferrous & Special Casting Exhibition is a professional foundry fair organized by China Foundry Association since 1998, which has taken advantage of the solid foundation in foundry industry in Shanghai metropolitan zone as well as its suburban ring.

  12. Walking in Place Through Virtual Worlds

    DEFF Research Database (Denmark)

    Nilsson, Niels Chr.; Serafin, Stefania; Nordahl, Rolf

    2016-01-01

    Immersive virtual reality (IVR) is seemingly on the verge of entering the homes of consumers. Enabling users to walk through virtual worlds in a limited physical space presents a challenge. With an outset in a taxonomy of virtual travel techniques, we argue that Walking-in-Place (WIP) techniques ....... Finally, we summarize work we have performed in order to produce more natural WIP locomotion and present unexplored topics which need to be address if WIP techniques are to provide perceptually natural walking experiences....

  13. Application of the gel casting process in iron powder metallurgy

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    The effects of various gel casting process parameters such as the dispersant and solid loading on the rheology of Fe slurries, molding, and sintering behaviors were studied. The relationship between solid loading and viscidity in the process of iron base powder metallurgy was researched to obtain better microstructure and properties. The results showed that the viscosity of Fe slurries is obviously reduced with the increase of the dispersant. The suitable parameters are as follows: the solid loading is 61% and sintering temperature is 1180℃. Iron parts with relatively high density and better properties were obtained by the gel casting process.

  14. Teaching Geoscience in Place for Local Diversity and Sustainability

    Science.gov (United States)

    Semken, S.

    2008-12-01

    within the Greater Southwest. Field studies are included as often as possible. Students review and discuss the geoscientific context and social implications of selected regional issues such as mining and water management. Courses are open to all and promoted to in-service and pre-service K-12 teachers. Front-end, formative, and summative evaluations use mixed methods based in theories of place attachment and experiential learning. Psychometric surveys of the diverse participants reveal variable prior senses of place and limited correlation with expected predictors such as ethnicity, but pre- and post-surveys show significant relative increases in sense of place. From these data and our qualitative findings (coded from participant observations, analysis of student products, and semi-structured exit interviews) we infer that students' knowledge of and attachments to Southwest places were enhanced by the place-based approach to teaching.

  15. Development of low-temperature high-strength integral steel castings for offshore construction by casting process engineering

    OpenAIRE

    Lim Sang-Sub; Mun Jae-Chul; Kim Tae-Won; Kang Chung-Gil

    2014-01-01

    In casting steels for offshore construction, manufacturing integral casted structures to prevent fatigue cracks in the stress raisers is superior to using welded structures. Here, mold design and casting analysis were conducted for integral casting steel. The laminar flow of molten metal was analyzed and distributions of hot spots and porosities were studied. A prototype was subsequently produced, and air vents were designed to improve the surface defects caused by the release of gas. A radio...

  16. The place of philosophy in European culture

    OpenAIRE

    Dummett, Michael

    2007-01-01

    In this paper the author investigates the place of philosophy in European culture. Philosophy has taken a considerable time to be recognised, or to recognise itself, as distinct from other disciplines. Although philosophy gave birth to physics and, more recently, to other sciences, it is not seen as a “technical” subject, like mathematics and natural sciences, or even social sciences such as economics. Philosophy is available to the general (educated) public while the technical subjects ar...

  17. Thin Wall Iron Castings

    Energy Technology Data Exchange (ETDEWEB)

    J.F. Cuttino; D.M. Stefanescu; T.S. Piwonka

    2001-10-31

    Results of an investigation made to develop methods of making iron castings having wall thicknesses as small as 2.5 mm in green sand molds are presented. It was found that thin wall ductile and compacted graphite iron castings can be made and have properties consistent with heavier castings. Green sand molding variables that affect casting dimensions were also identified.

  18. Low-Gravity Investigations in Cast-Iron Processing

    Science.gov (United States)

    Frankhouser, W. L.

    1982-01-01

    Report on the state of the art in cast-iron processing identifies possible improvements that might result from processing in absence of gravity. Report suggests areas in which the knowledge of gravitational effects could eventually lead to practical improvements in material performance.

  19. Numerical modelling of stresses and deformations in casting processes

    DEFF Research Database (Denmark)

    Hattel, Jesper Henri

    1997-01-01

    Keywords: Stresses and deformations, casting, governing equations, thermal strain, control volume method......Keywords: Stresses and deformations, casting, governing equations, thermal strain, control volume method...

  20. Eddy current measurement system evaluation for corrosion depth determination on cast aluminum aircraft structure

    Science.gov (United States)

    Singh, Surendra; Greving, Dan; Kinney, Andy; Vensel, Fred; Ohm, Jim; Peeler, Mike

    2013-01-01

    An eddy current (EC) technique was developed to determine the corrosion depth on a bare flange face of a cast aluminum A356-T6 aircraft engine structure. The EC response and the corrosion depths determined through metallurgical cross sections were used to develop an empirical relation between EC response and depth. The EC technique and depth determination are used to inspect the engine structures during overhaul to determine if they are fit for continued service. An accurate and reliable Non-Destructive Inspection is required to ensure that structures returned to service are safe for continued operation. NDE system reliability demonstrations of the eddy current technique are traditionally reported in terms of Probability of Detection (POD) data using MIL-HDBK-1823A. However, the calculation of POD data is based on a simple linear predictive model that is valid only if certain criteria are met. These are: 1) NDE system response is measurable (i.e. continuous data), 2) Flaw size is known and measurable (i.e. continuous data), 3) relationship between the NDE system response and flaw size is linear (or linear on a log scale), 4) variation in measured responseresponse around a predicted response for a given flaw size is normally distributed, 5) the variation around the predicted response is constant (i.e. variation does not change with flaw size), and 6) inherent variability in the NDE system is known and fully understood. In this work, a Measurement System Evaluation (MSE) of the Eddy Current System was used to address some of these concerns. This work was completed on two aircraft structures having varying corrosion depths. The data were acquired in a random manner at fifty regions of interests (ROIs). Three operators participated in this study, and each operator measured Eddy Current response three times in each ROI. In total, there were four hundred and fifty data points collected. Following this, the two structures were sectioned for measuring corrosion depth. The

  1. Caste-specific compounds in male carpenter ants.

    Science.gov (United States)

    Brand, J M; Duffield, R M; Macconnell, J G; Blum, M S; Fales, H M

    1973-01-26

    Three caste-specific substances new to arthropod glandular secretions occur in the mandibular glands of male ants of five species in the genus Camponotus. These volatile compounds, which are not found in alate females or workers, have been identified as methyl 6-methyl salicylate, 2,4-dimethyl-2-hexenoic acid, and methyl anthranilate. The free acid has not been described previously.

  2. Awareness Programs and Change in Taste-based Caste Prejudice

    DEFF Research Database (Denmark)

    Banerjee, Ritwik; Gupta, Nabanita Datta

    2015-01-01

    and the reduction is sustained over time. Second, we find that the treatment reduces the prejudice levels of those in the left tail of the prejudice distribution - the group which can potentially affect real outcomes as predicted by the theory. And finally, a larger share of the treatment group subjects exhibit...... favorable opinion about reservation in jobs for the lower caste....

  3. Quantitative comparison of caste differences in honeybee hemolymph.

    Science.gov (United States)

    Chan, Queenie W T; Howes, Charles G; Foster, Leonard J

    2006-12-01

    The honeybee, Apis mellifera, is an invaluable partner in agriculture around the world both for its production of honey and, more importantly, for its role in pollination. Honeybees are largely unexplored at the molecular level despite a long and distinguished career as a model organism for understanding social behavior. Like other eusocial insects, honeybees can be divided into several castes: the queen (fertile female), workers (sterile females), and drones (males). Each caste has different energetic and metabolic requirements, and each differs in its susceptibility to pathogens, many of which have evolved to take advantage of the close social network inside a colony. Hemolymph, arthropods' equivalent to blood, distributes nutrients throughout the bee, and the immune components contained within it form one of the primary lines of defense against invading microorganisms. In this study we have applied qualitative and quantitative proteomics to gain a better understanding of honeybee hemolymph and how it varies among the castes and during development. We found large differences in hemolymph protein composition, especially between larval and adult stage bees and between male and female castes but even between adult workers and queens. We also provide experimental evidence for the expression of several unannotated honeybee genes and for the detection of biomarkers of a viral infection. Our data provide an initial molecular picture of honeybee hemolymph, to a greater depth than previous studies in other insects, and will pave the way for future biochemical studies of innate immunity in this animal.

  4. The analysis of the possibility of the application of the casting waxes in the process RP

    OpenAIRE

    G. Budzik

    2009-01-01

    The article presents analysis of possibility of application of casting waxes in process of rapid prototyping of casting models in silicone the matrices. The researches were made on casting waxes applied to the manufacturing of precise casting models and also the model system. Testing waxes are intended nominally to the processing in process of the injection. The determining of possibility processing of waxes in silicone forms was purpose of researches. Researches concerned of whole manufactur...

  5. Flow of Steel in Mold Region During Continuous Casting

    Institute of Scientific and Technical Information of China (English)

    ZHANG Xing-guo; ZHANG Wen-xiao; JIN Jun-ze; J. W. Evans

    2007-01-01

    The particle image velocimetry (PIV) technique was used to study the fluid flow phenomena that occurred during continuous casting, using a water model with dimensions of 1 840 mm×280 mm. Two types of solidified shells, i.e., the smooth type and the coarse type, were used to characterize the dendrite in order to simulate different liquid-solid interfacial conditions. The influence of the nozzle angle and the immersion depth of nozzle, as well as the casting speed on the flow behavior was investigated quantitatively. The results were as follows: (1) There are two large recirculations above and below the fluid jet in the mold, respectively, under the smooth interface condition. However, in the case of the dendrite solidified shell, it was found that the flow velocity of the fluid decreased and more smaller vortices appeared in the upper region of the mold. (2) The angle and the immersion depth of nozzle are two important factors affecting the flow pattern, and they are also capable of bringing about the change in the flow direction. (3) The higher the casting speed, the higher are the jet stream and the impacting point on the narrow face. However, the high casting speed causes serious fluctuation of the meniscus, and correspondingly leads to various defects.

  6. High-strength cast irons used for manufacturing parts of vaz passenger cars

    Science.gov (United States)

    Kitaigora, N. I.

    1996-10-01

    Methods for solving problems arising in the production of high-strength cast iron with stable properties and structure are considered. Results of introduction of new grades of high-strength cast iron instead of malleable cast iron and camshaft cast iron in the Volzhskii Automobile Plant are described.

  7. Mechanisms and mechanics of porosity formation in ductile iron castings

    Directory of Open Access Journals (Sweden)

    M. Perzyk

    2007-12-01

    Full Text Available Shrinkage defects in ductile iron castings can be of two basic types: shrinkage cavities associated with the liquid contraction prior to the expansion period of the iron as well as the porosity, which may appear even if the liquid shrinkage is fully compensated. In the present paper two possible mechanisms of the porosity are presented and analyzed. The first one is the Karsay’s mechanism based on the secondary shrinkage concept. The second one is the mechanism acting during the expansion period of the iron, first suggested by Ohnaka and co-authors and essentially modified by the present authors. The mechanical interactions between casting and mould are determined for the both mechanisms. Their analysis leads to the conclusion, that porosity forms during expansion period of the melt. The direct cause is the negative pressure which appears in the central part of the casting due to the differences in expansion coefficients of the fast cooling surface layer and slow cooling inner region. Observations concerning feeding behavior of ductile iron castings, based on this mechanism, agree well with industrial practice. The secondary shrinkage is not only needless to induce the porosity, but the corresponding mechanism of its occurrence, proposed by Karsay, does not seem to be valid.

  8. CASTE Revisited: Principles of Course Design in a Hypertext Environment.

    Science.gov (United States)

    Scott, Bernard

    2000-01-01

    Describes CASTE (Course Assembly System and Tutorial Environment) that was developed to help students choose appropriate learning strategies in a hypertext environment. Highlights include the need for principles of course design; resource-based learning and computer-aided learning; conversation theory; and a comparison to other approaches.…

  9. Clay dispersability in moist earthworm casts of different soils.

    NARCIS (Netherlands)

    Marinissen, J.C.Y.; Nijhuis, E.; Breemen, van N.

    1996-01-01

    Earthworms were fed soil from two polders, differing in soil age and land use (grass and arable). Sterilised and non-sterilised moist earthworm casts were, directly or after ageing (for 2, 4, 8 and 20 weeks), analysed for clay dispersability and polysaccharide content, either as such, or after treat

  10. INFLUENCE OF FILM STRUCTURE AND LIGHT ON CHARGE TRAPPING AND DISSIPATION DYNAMICS IN SPUN-CAST ORGANIC THIN-FILM TRANSISTORS MEASURED BY SCANNING KELVIN PROBE MICROSCOPY

    Energy Technology Data Exchange (ETDEWEB)

    Teague, L.; Moth, M.; Anthony, J.

    2012-05-03

    Herein, time-dependent scanning Kelvin probe microscopy of solution processed organic thin film transistors (OTFTs) reveals a correlation between film microstructure and OTFT device performance with the location of trapped charge within the device channel. The accumulation of the observed trapped charge is concurrent with the decrease in I{sub SD} during operation (V{sub G}=-40 V, V{sub SD}= -10 V). We discuss the charge trapping and dissipation dynamics as they relate to the film structure and show that application of light quickly dissipates the observed trapped charge.

  11. Casting Ductile Iron in Layer Moulds Made from Ecological Sands

    Directory of Open Access Journals (Sweden)

    M. Rączka

    2012-09-01

    Full Text Available The article contains the results of tests performed under the target project in Hardtop Foundry Charsznica.The objective of the tests and studies was to develop a technology of making high-quality ductile iron castings, combined witheffective means of environmental protection. The studies presented in this article related to castings weighing from 1 to 300 kg made from ductile iron of grades 400-15 and 500-7, using two-layer moulds, where the facing and core sand was the sand with an alkaline organic binder, while backing sand was the sand with an inorganic geopolymer binder.A simplified method of sand reclamation was applied with possible reuse of the reclaim as an addition to the backing sand. The castiron spheroidising treatment and inoculation were selected taking into account the specific conditions of Hardtop Foundry. A pilot batch of castings was made, testing the gating and feeding systems and using exothermic sleeves on risers. The study confirmed the validity of the adopted concept of making ductile iron castings in layer moulds, while maintaining the content of sand with an organic binder at a level of maximum 15%.

  12. The place of the dream in psychotherapy.

    Science.gov (United States)

    Kaplan, D M

    1989-01-01

    The dream assumed an exceptional place in clinical practice beginning with Freud's extraordinary use of dream interpretation in his early presentations of psychoanalytic theory. Early students of analysis misconstrued this emphasis on the dream in theoretical exposition to apply to clinical practice as well. Eventually this difference was clarified, but there is still something exceptional about the dream in clinical practice that survives clarifications of this early misapprehension. The author reviews the historical issues, identifies the exceptional aspects of the dream in psychoanalytic practice, discusses some problems this phenomenon creates for the analyst, and describes several stereotypical attitudes toward the practice of dream interpretation.

  13. Some problems in the production of ductile irons by investment casting

    Institute of Scientific and Technical Information of China (English)

    Yu Bo; Cai Qizhou; Wei Bokang

    2008-01-01

    Because of the excellent performance of ductile irons and the unique superiority of investment casting, the preparation of complicated and thin-wall ductile iron castings by investment casting shows a good development prospect. In this present work, combined with the actual product experiments, the characteristics of shell making,spheroidization, inoculation and defect prevention are presented, and some suggestions are given for investment casting of ductile iron.

  14. Some problems in the production of ductile irons by investment casting

    OpenAIRE

    2008-01-01

    Because of the excellent performance of ductile irons and the unique superiority of investment casting, the preparation of complicated and thin-wall ductile iron castings by investment casting shows a good development prospect. In this present work, combined with the actual product experiments, the characteristics of shell making, spheroidization, inoculation and defect prevention are presented, and some suggestions are given for investment casting of ductile iron.

  15. Some problems in the production of ductile irons by investment casting

    Directory of Open Access Journals (Sweden)

    Yu Bo

    2008-02-01

    Full Text Available Because of the excellent performance of ductile irons and the unique superiority of investment casting, the preparation of complicated and thin-wall ductile iron castings by investment casting shows a good development prospect. In this present work, combined with the actual product experiments, the characteristics of shell making, spheroidization, inoculation and defect prevention are presented, and some suggestions are given for investment casting of ductile iron.

  16. The structure and mechanical properties of pearlitic-ferritic vermicular cast iron

    Directory of Open Access Journals (Sweden)

    E. Guzik

    2012-01-01

    Full Text Available The results of studies on the use of magnesium alloy in modern Tundish + Cored Wire injection method for production of vermicular graphite cast irons were described. The injection of Mg Cored Wire length is a treatment method which can be used to process iron melted in an electric induction furnace. This paper describes the results of using a high-magnesium ferrosilicon alloy in cored wire for the production of vermicular graphite cast irons at the; Tundish + Cored Wire to be injected methods (PE for pearlitic-ferritic matrix GJV with about 25 %ferrite content. The results of calculations and experiments have indicated the length of the Cored Wire to be injected basing on the initial sulfur content and weight of the treated melt. The paper presents a microstructure matrix and vermicular graphite in standard sample and different walled castings. The results of numerous trials have shown that the magnesium Tundish + PE Method process can produce high quality vermicular graphite irons under the specific industrial conditions of the above mentioned foundries.

  17. Pattern recognition in the automatic inspection of aluminium castings

    Energy Technology Data Exchange (ETDEWEB)

    Mery, D. [Univ. de Santiago de Chile, Santiego (Chile); Silva, R.R. da; Rebello, J.M.A. [Univ. Federal do Rio de Janeiro (Brazil). Eng. Metalurgical/Materiais; Caloba, L.P. [Univ. Federal do Rio de Janeiro (Brazil). Eng. Electronica

    2003-07-01

    In this paper, we report the results obtained recently by analysing around 400 features measured from 23.000 regions segmented in 50 radioscopic images of cast aluminium wheels with defects. The extracted features are divided into two groups: geometric features (area, perimeter, height, width, roundness, Fourier descriptors, invariant moments, and other shape factors) and grey value features (mean grey value, mean gradient in the boundary, mean second derivate in the region, radiographic contrasts, invariant moments with grey value information, local variance, textural features based on the co-occurrence matrix, coefficients of the discrete Fourier transform, the Karhunen Loeve transform and the discrete cosine transform). We propose a new contrast feature obtained from grey level profiles along straight lines crossing the segmented potential defects. Analysing the area Az under the receiver operation characteristic (ROC) curve, this feature presents the best individual detection performance yielding an area Az=0.9944. In order to make a compact pattern representation and a simple decision strategy, the number of features are reduced using feature selection approaches. The relevance of the selected features is evaluated by calculation of linear correlation coefficient. The results are shown in tables of the linear correlation coefficients between features, and among features and class of defect. In addition, statistical classifiers and classifiers based on neural networks are implemented in order to establish decision boundaries in the space of the selected features which separate patterns (our segmented regions) belonging to two different classes (regular structure or defects).

  18. Sacred places in global big cities

    DEFF Research Database (Denmark)

    Greve, Anni

    the relation between the sacred and the profane, and about the role of the sacred in modern societies. The question is if the development of modern societies has implied the gradual abolishment of religious beliefs, rituals and rites, or has it on the contrary implied the installment of new forms of religious...... beliefs and sacred places, which are cultivated through regular rituals and rites, just as some traditional societies have cultivated for instance totemism. This paper will take its point of departure in Durkheim’s study of The Elementary Forms of Religious Life from 1912. Then it will turn...

  19. CA Investment Casting Process of Complex Castings

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    CA (Computer aided) investment casting technique used in superalloy castings of aerospace engine parts was presented. CA investment casting integrated computer application, RP (Rapid Prototyping) process, solidification simulation and investment casting process. It broke the bottle neck of making metal die. Solid model of complex parts were produced by UGII or other software, then translated into STL(Stereolithography) file, after RP process of SLS(Selective Laser Sintering), wax pattern used in investment ...

  20. Materials for Advanced Ultrasupercritical Steam Turbines Task 4: Cast Superalloy Development

    Energy Technology Data Exchange (ETDEWEB)

    Thangirala, Mani

    2015-09-30

    The Steam Turbine critical stationary structural components are high integrity Large Shell and Valve Casing heavy section Castings, containing high temperature steam under high pressures. Hence to support the development of advanced materials technology for use in an AUSC steam turbine capable of operating with steam conditions of 760°C (1400°F) and 35 Mpa (5000 psia), Casting alloy selection and evaluation of mechanical, metallurgical properties and castability with robust manufacturing methods are mandated. Alloy down select from Phase 1 based on producability criteria and creep rupture properties tested by NETL-Albany and ORNL directed the consortium to investigate cast properties of Haynes 282 and Haynes 263. The goals of Task 4 in Phase 2 are to understand a broader range of mechanical properties, the impact of manufacturing variables on those properties. Scale up the size of heats to production levels to facilitate the understanding of the impact of heat and component weight, on metallurgical and mechanical behavior. GE Power & Water Materials and Processes Engineering for the Phase 2, Task 4.0 Castings work, systematically designed and executed casting material property evaluation, multiple test programs. Starting from 15 lbs. cylinder castings to world’s first 17,000 lbs. poured weight, heavy section large steam turbine partial valve Haynes 282 super alloy casting. This has demonstrated scalability of the material for steam Turbine applications. Activities under Task 4.0, Investigated and characterized various mechanical properties of Cast Haynes 282 and Cast Nimonic 263. The development stages involved were: 1) Small Cast Evaluation: 4 inch diam. Haynes 282 and Nimonic 263 Cylinders. This provided effects of liquidus super heat range and first baseline mechanical data on cast versions of conventional vacuum re-melted and forged Ni based super alloys. 2) Step block castings of 300 lbs. and 600 lbs. Haynes 282 from 2 foundry heats were evaluated which

  1. Structure of Water Mist Stream and its Impact on Cooling Efficiency of Casting Die

    Directory of Open Access Journals (Sweden)

    R. Władysiak

    2012-04-01

    Full Text Available The work is a continuation of research on the use water mist cooling in order to increase efficiency of die-casting aluminum alloys. The paper presents results of research and analysis process, spraying water and generated a stream of water mist, the effect of the type of nozzle, the nozzle size and shape of the emitting of the water mist on the wall surface of casting die on the microstructure and geometry of water mist stream and cooling efficiency. Tests were used to perform high-speed camera to record video in the visible and infrared camera. Results were used to develop a computerized image analysis and statistical analysis. The study showed that there are statistical relationships between water and air flow and geometry of the nozzle and nozzle emitting a stream of microstructure parameters of water mist and heat the incoming stream. These relationships are described mathematical models that allow you to control the generating of adequate stream of water mist and a further consequence, the cooling efficiency of casting die.

  2. Improvement of Structure and Properties of Cast Ferrite-Pearlite Steels for Freight Railway Cars

    Directory of Open Access Journals (Sweden)

    A. Rabinovich

    2008-03-01

    Full Text Available As it i s known For increasing of propcnics (YTS 2 380 MPa of cast stcds i t is c f k ~ i v tco incrcasc conlcnt o f alhsti~uiionaal lloyingclcrncnts, (Si, Mn, Cr, Ni. 1 lowevcr it lcads to rising in pricc olstccl ton. lncrcasing of Si and Mn conrcnl only is limitcd hy decreasing o lductility and weld nhility. As a rule silicon contcnt at ~hcsca ccls is not highcr than 0.4-0.67'0 and Si:Mn ratio is not highcr khan 1:2. Nowfor grain rcfincmcnt ~wc sin oculation of stcct by nitrogcn and clcincnrs with high chcmical affinity to nltmgcn. Mostly vanadium i s usd.howcvcr niobium sornctime is uscd. Dissldvantagcs of this arc high cost of alloying clcmcnrs and low thcrrnodynamic stability OFvanadium and niobium nitridcs. Parlicles of V(C,N and Nh(C.N dissolvc during hcating fnr licnt trcatmcnt or during wclding. It [cads lodccrcasing of grain refinement elfcc!.Adaptat ion or this microalloying stratcgy Tor casts producing For rrcight mil way cars let cstirnatc possibility of application thcsc casts in ancw gcnerazion freight railway cars.

  3. The mechanism of hot crack formation in Ti-6Al-4V during cold crucible continuous casting

    Institute of Scientific and Technical Information of China (English)

    2004-01-01

    Hot crack is one of common defects in castings, which often results in failure of castings. This work studies the formation of hot crack during cold crucible continuous casting by means of experiments and theoretical analysis. The results show that hot crack occurs on the surface and in the circumference of ingots, where the solidified shell and the solidification front meet each other. The tendency of hot cracking decreases with the increase of withdrawal velocities in some extent.The hot crack is caused mainly by the friction force between the shell and the crucible inner wall, and it takes place when the stress resulting from friction exceeds the tensile strength of the shell. The factors of μm, ht, hs and hm, affecting hot cracks are analyzed and verified. In order to decrease the tendency of hot cracks, technical parameters should be optimized by decreasingμm, ht, hs and hm.

  4. 'Desecration' in a Place of Refuge

    Directory of Open Access Journals (Sweden)

    Diana Glazebrook

    2013-08-01

    Full Text Available In this paper I explore two related questions: how does a particular site come to be perceived as sacred, and what is the impact of the destruction of something sacred when it occurs in a place of ‘refuge’? This study is situated on the island of New Guinea, in the experiences of West Papuan people from the Indonesian Province of Papua (formerly Irian Jaya, living as refugees across the international border in Papua New Guinea. The inquiry is grounded in two instances involving a refugee population in a place of refuge. The first instance involves the burning of a church built by a refugee congregation, and the second involves the large-scale occupation by a refugee population of another people’s land. A doubling effect is intended here. Forced migration can simultaneously render refugees vulnerable to the violence of others, and in the process of resettlement, refugees may have no real choice but to engage in actions that violate the land of others.

  5. Solid-particle erosion behavior of cast alloys used in the mining industry

    Institute of Scientific and Technical Information of China (English)

    Hakan Atapek; Sinan Fidan

    2015-01-01

    The erosive-wear response of five commercial ferrous-based cast alloys used for crushing was examined in this study. The micro-structures of the alloys were modified to elucidate the effect of microstructural features on wear. Erosion tests were conducted using alumi-num oxide particles (90–125 µm) at 70 m/s and a normal impact angle (90°). The worn surfaces were characterized by scanning electron mi-croscopy and 3D non-contact laser profilometry. It is found that (i) a pearlitic structure exhibiting a greater plastic deformation than both bainitic and martensitic structures shows the greatest resistance to erosive wear at normal impact and (ii) the fracture characteristics of car-bide and graphite particles plays an important role in determining the erosion wear behavior of the cast alloy matrices.

  6. New developments in high quality grey cast irons

    Directory of Open Access Journals (Sweden)

    Iulian Riposan

    2014-07-01

    Full Text Available The paper reviews original data obtained by the present authors, revealed in recent separate publications, describing specific procedures for high quality grey irons, and reflecting the forecast needs of the worldwide iron foundry industry. High power, medium frequency coreless induction furnaces are commonly used in electric melting grey iron foundries. This has resulted in low sulphur (1,500 °C, contributing to unfavourable conditions for graphite nucleation. Thin wall castings are increasingly produced by these electric melt shops with a risk of greater eutectic undercooling during solidification. The paper focused on two groups of grey cast irons and their specific problems: carbides and graphite morphology control in lower carbon equivalent high strength irons (CE=3.4%-3.8%, and austenite dendrite promotion in eutectic and slightly hypereutectic irons (CE=4.1%-4.5%, in order to increase their strength characteristics. There are 3 stages and 3 steps involving graphite formation, iron chemistry and iron processing that appear to be important. The concept in the present paper sustains a threestage model for nucleating flake graphite [(Mn,XS type nuclei]. There are three important groups of elements (deoxidizer, Mn/S, and inoculant and three technological stages in electric melting of iron (superheat, pre-conditioning of base iron, final inoculation. Attention is drawn to a control factor (%Mn x (%S ensuring it equals to 0.03 – 0.06, accompanied by 0.005wt.%–0.010wt.% Al and/or Zr content in inoculated irons. It was found that iron powder addition promotes austenite dendrite formation in eutectic and slightly eutectic, acting as reinforcement for the eutectic cells. But, there is an accompanying possible negative influence on the characteristics of the (Mn,XS type graphite nuclei (change the morphology of nuclei from polygonal compact to irregular polygonal, and therefore promote chill tendency in treated irons. A double addition (iron

  7. New developments in high quality grey cast irons

    Institute of Scientific and Technical Information of China (English)

    Iulian Riposan; Mihai Chisamera; Stelian Stan

    2014-01-01

    The paper reviews original data obtained by the present authors, revealed in recent separate publications, describing speciifc procedures for high quality grey irons, and relfecting the forecast needs of the worldwide iron foundry industry. High power, medium frequency coreless induction furnaces are commonly used in electric melting grey iron foundries. This has resulted in low sulphur (1,500 °C), contributing to unfavourable conditions for graphite nucleation. Thin wall castings are increasingly produced by these electric melt shops with a risk of greater eutectic undercooling during solidiifcation. The paper focused on two groups of grey cast irons and their speciifc problems: carbides and graphite morphology control in lower carbon equivalent high strength irons (CE=3.4%-3.8%), and austenite dendrite promotion in eutectic and slightly hypereutectic irons (CE=4.1%-4.5%), in order to increase their strength characteristics. There are 3 stages and 3 steps involving graphite formation, iron chemistry and iron processing that appear to be important. The concept in the present paper sustains a three-stage model for nucleating flake graphite [(Mn,X)S type nuclei]. There are three important groups of elements (deoxidizer,Mn/S, and inoculant) and three technological stages in electric melting of iron (superheat, pre-conditioning of base iron, ifnal inoculation). Attention is drawn to a control factor (%Mn) x (%S) ensuring it equals to 0.03- 0.06, accompanied by 0.005wt.%-0.010wt.% Al and/or Zr content in inoculated irons. It was found that iron powder addition promotes austenite dendrite formation in eutectic and slightly eutectic, acting as reinforcement for the eutectic cells. But, there is an accompanying possible negative influence on the characteristics of the (Mn,X)S type graphite nuclei (change the morphology of nuclei from polygonal compact to irregular polygonal, and therefore promote chill tendency in treated irons). A double addition (iron powder + inoculant

  8. Temperature-induced anomalous structural changes of Al-12wt.%Sn-4wt.%Si melt and its influence on as-cast structure

    Directory of Open Access Journals (Sweden)

    Wang Zhiming

    2010-05-01

    Full Text Available The temperature dependence of the viscosity of liquid Al-12wt.%Sn-4wt.%Si was studied with a high-temperature viscosity apparatus. Anomalous changes of viscosity of the melt were found at 1,103 K and 968 K in the cooling process, which indicates anomalous structural changes of the melt. It is calculated that the anomalous structural change is associated with an abrupt decrease of atomic clusters’ size and activation energy in the melt. According to the temperature of the anomalous structural changes, melt heat treatment process (quenching from superheat to pouring temperature was performed on Al-12wt.%Sn-4wt.%Si melt prior to pouring, aimed to keep the small atomic clusters from higher temperature to lower pouring temperature. The results suggest that relatively small atomic clusters at the pouring temperature in the melt could generate a deep under-cooling of nucleation in the subsequent solidification process, and refine the as-cast structure. After being quenched from superheating to pouring temperature, the relatively small atomic clusters, especially the Si-Si clusters in the melt will grow to equilibrium state (relatively big atomic clusters with holding time, resulting in the prominent coarsening of the Si morphology in the as-cast structure.

  9. Making Place in the Media City

    Directory of Open Access Journals (Sweden)

    Maja Klausen

    2012-11-01

    Full Text Available The article discusses practices of placemaking through empirical fieldwork undertaken in the subculture of urban exploration in Copenhagen. The making and experience of place is discussed, firstly, in relation to methodology and academic representation and secondly, in relation to urban space and media. The article begins by suggesting that the ethnographic research process should be grasped as the making of an ‘ethnographic place’ (Pink 2010, which invites readers/audiences to imagine themselves into the places represented. Based on findings from the fieldwork, the article moves on to the methodologies associated with the examination of urban exploration and its academic representation. The article points to a ‘multi-sited’ (Marcus 1995 and mobile ethnography (Lee & Ingold 2006 that acknowledges the ethnographer as ‘emplaced’ (Howes 2005 in the research setting. Finally, urban exploration and the placemaking practices involved are positioned in a wider theoretical framework focusing on social media and urban space. The urban explorers use different social media platforms to share information and pictures, which is said to accelerate ‘a mediatised sense of place’ (Jansson & Falkheimer 2006. Urban exploration is seen as a practice tied to the late modern ‘media city’ (Fornäs 2006; McQuire 2010, where spatial experience is transformed due to the increased convergence of mobile and pervasive media with urban space.

  10. Making Place in the Media City

    DEFF Research Database (Denmark)

    Klausen, Maja

    2012-01-01

    The article discusses practices of placemaking through empirical fieldwork undertaken in the subculture of urban exploration in Copenhagen. The making and experience of place is discussed, firstly, in relation to methodology and academic representation and secondly, in relation to urban space and...... exploration is seen as a practice tied to the late modern ‘media city’ (Fornäs 2006; McQuire 2010), where spatial experience is transformed due to the increased convergence of mobile and pervasive media with urban space....... and media. The article begins by suggesting that the ethnographic research process should be grasped as the making of an ‘ethnographic place’ (Pink 2010), which invites readers/audiences to imagine themselves into the places represented. Based on findings from the fieldwork, the article moves...... and the placemaking practices involved are positioned in a wider theoretical framework focusing on social media and urban space. The urban explorers use different social media platforms to share information and pictures, which is said to accelerate ‘a mediatised sense of place’ (Jansson & Falkheimer 2006). Urban...

  11. Aluminium composites casting in rotating magnetic field

    Directory of Open Access Journals (Sweden)

    M. Cholewa

    2008-04-01

    Full Text Available In this paper technological and material conception of composite manufacturing with intensify of ex-situ powders and some results was shown. Technology of powders stirring with liquid metal in the crucible was shown. For composites required dispersion of reinforcement and matrix crystallization was assisted with rotating electromagnetic field. Improvement of reinforcing particles distribution can be observed. Composite structure was studied with use of light microscopy. Electromagnetic field processing positive influence on reinforcing phase distribution and matrix crystallization process was proved.

  12. Ontogenic Caste Differences in the Van der Vecht Organ of Primitively Eusocial Neotropical Paper Wasps

    Science.gov (United States)

    de Souza, André Rodrigues; Petrocelli, Iacopo; Lino-Neto, José; Santos, Eduardo Fernando; Noll, Fernando Barbosa; Turillazzi, Stefano

    2016-01-01

    Recent studies have reported incipient morphological caste dimorphism in the Van der Vecht organ size of some temperate Polistes paper wasps. Whether species other than the temperate ones show a similar pattern remains elusive. Here, we have studied some Neotropical Polistes species. By comparing females collected through the year, we showed caste related differences in the size of the Van der Vecht organ in P. ferreri (body size corrected Van der Vech organ size of queens = 0.45 ± 0.06, workers = 0.38 ± 0.07 mm2, p = 0.0021), P. versicolor (body size corrected Van der Vech organ size of queens = 0.54 ± 0.11, workers = 0.46 ± 0.09 mm2, p = 0.010), but not P. simillimus (body size corrected Van der Vech organ size of queens = 0.52 ± 0.05, workers = 0.49 ± 0.06 mm2, p = 0.238). Therefore, it seems that queens and workers of some Neotropical Polistes have diverged in their ontogenic trajectory of the Van der Vecht organ size, providing clear evidence for incipient morphological caste dimorphism. As Polistes are distributed mostly in the tropics, we propose that physical caste differences may be widespread in the genus. Also, we highlight that morphological divergence in the queen–worker phenotypes may have started through differential selection of body structures, like the Van der Vecht organ. PMID:27167514

  13. Advanced casting technologies for lightweight automotive applications

    Directory of Open Access Journals (Sweden)

    Alan A. Luo

    2010-11-01

    Full Text Available This paper provides an overview of alloy and process developments in aluminum and magnesium castings for lightweight automotive applications. Wear-resistant aluminum alloys, creep-resistant and high strength/ductility magnesium alloys have been developed for automotive applications. On the process front, vacuum-assisted die casting and high vacuum die casting technologies have been developed for high-integrity body and chassis applications. Thin-wall and hollow casting components are being produced by low-pressure die casting processes for structural applications. Overcasting technology is gaining traction and has enabled mixed material designs for automotive sub-systems such as engine cradles and instrument panel beams. Simulation tools developed to predict the interfacial interactions of the dissimilar components and the structural integrity of the overcast systems are being validated in the casting trials.

  14. Power plant waste disposals in open-cast mines

    Energy Technology Data Exchange (ETDEWEB)

    Herstus, J.; Stastny, J. [AGE s.r.o. - Aplikovana Geotechnika a Ekologie, Thamova (Czechoslovakia)

    1995-12-01

    High population density in Czech Republic has led, as well as in other countries, to strong NIMBY syndrome influencing the waste disposal location. The largest thermal power plants are situated in neighborhood of extensive open-cast brown coal mines with huge area covered by tipped clayey spoil. Such spoil areas, technically almost useless, are potential space for power giant waste disposal position. There are several limitations, based on specific structural features of tipped clayey spoil, influencing decision to use such area as site for waste disposal. Low shear strength and extremely high compressibility belong to the geotechnical limitations. High permeability of upper ten or more meters of tipped spoil and its changes with applied stress level belongs to transitional features between geotechnical and environmental limitations. The problems of ash and FGD products stabilized interaction with such subgrade represent environmental limitation. The paper reports about the testing procedure developed for thickness and permeability estimation of upper soil layer and gives brief review of laboratory and site investigation results on potential sites from point of view of above mentioned limitations. Also gives an outline how to eliminate the influence of unfavorable conditions.

  15. Structural and magnetic properties of rapidly quenched and as-cast bulk NdFeBCu alloys

    Energy Technology Data Exchange (ETDEWEB)

    Sanchez Ll, J.L. [Laboratorio de Magnetismo, Facultad de Fisica-IMRE, Universidad de La Habana, Havana 10400 (Cuba)]. E-mail: sanchez@fisica.uh.cu; Bustamante S, R. [Laboratorio de Magnetismo, Facultad de Fisica-IMRE, Universidad de La Habana, Havana 10400 (Cuba); Barthem, V.M.T.S. [Instituto de Fisica, UFRJ, CT, Bloco A, C.P. 68528, 21945-970, Rio de Janeiro (Brazil); Miranda, P.E.V. de [Departamento de Engenharia Metalurgica e de Materiais, COPPE, UFRJ, C.P. 68505, 21945-970, Rio de Janeiro (Brazil)

    2005-07-15

    A study of the structural and magnetic properties of as-cast and melt spun (x)Nd{sub 2}Fe{sub 14}B(100-x)Nd{sub 70}Cu{sub 30} alloys (x=10, 50 and 75%wt.) is presented. In as-cast alloys for x=10wt%. the formation of a high coercivity phase, referred to as N (T{sub C}=240 deg. C, {sub i}H{sub C}=4.9kOe) is found. N is a (Nd-Fe)-based phase with a Fe/Nd ratio lower than that of phase Nd{sub 2}Fe{sub 14}B ({phi}). It is suggested that this phase is related to the A{sub 1} phase found in binary Nd-Fe alloys. In melt-spun alloys, at the same x value of 10wt%, another hard phase is found which is suggested to be the Nd{sub 6}Fe{sub 13}Cu {delta}-phase (T{sub C}=192 deg. C, {sub i}H{sub C}=4.8kOe). Transmission electron microscope (TEM) micrographs of the ribbons with x=10wt% shows the formation of nanograins with a non-uniform grain size distribution. In cast alloys with x=50 and 75wt% large slab-like grains of {phi} are formed, in the inter-granular region a Nd-Cu eutectic phase and Nd grains, are observed. High coercivities are obtained in ribbons with x=50wt% ({sub i}H{sub C}=19.7kOe) and 75wt% ({sub i}H{sub C}=13.0kOe). A slight reduction in the Curie temperature of the {phi}-phase with respect to the bulk value is found in these ribbons.

  16. Effect of combined electromagnetic fields on surface quality and structure of a HDC casting 5182 Al alloy ingot

    Institute of Scientific and Technical Information of China (English)

    Qingfeng ZHU; Zhihao ZHAO; Yubo ZUO; Xiangjie WANG; Jianzhong CUI

    2012-01-01

    5182 Al alloy ingots with the diameters of 100 mm are produced by conventional and combined electromagnetic fields (CEMF) horizontal direction chill (HDC) casting process.The effect of CEMF on the ingot surface quality and floating grains is investigated.The results show that the CEMF is effective in reducing the segregation layer in both top and bottom sub-surfaces.Big floating grains with coarse dendrite arms mainly distribute in the crescent-shaped area near the bottom in the conventional HDC casting ingot.With the application of the CEMF,they disappear in the whole cross section of the HDC casting ingot and the equiaxed grains are significantly refined.

  17. STUDY ON THE MECHANISM OF GRAPHITIZATION IN MOLTEN CAST IRON PROMOTED BY ELECTROPULSE DISCHARGE

    Institute of Scientific and Technical Information of China (English)

    G.W. Chang; J.S. Wang; J.Z. Wang; Q.G. Xue; D.Q. Zhou; D.Q. Cang

    2004-01-01

    From the points of both molten cast iron structure and the appearing ratio of electrons in outer-layer of different atoms, analysis on enhancement mechanism of graphitization ability after processing of the iron by pulse electric discharge has been made, and the theory has been proofed by corresponding experiments. The results show that when the molten cast iron is being processed by pulse electric discharge, both the size of crystal embryos that composed by Fe and C atoms as well as the number of clusters can bereduced, even be separated by such discharging; consequently results in the segregation of C atoms in the molten cast iron near the cathode of discharging. The nucleation of graphite in these areas of the iron has been promoted at the discharging temperature; even though such degree has not been reached, the most favorable nucleation conditions of graphite can be at least created. Under the preconditions of not breaking up the graphite crystal embryos, with proper adjustment of discharging frequency, the stronger of the electric field and the longer of the pulsation treatment time are, the more graphitization ability of the molten cast iron is. The theoretical analysis on the above rules consists well with experimental results.

  18. The Configurable Aperture Space Telescope (CAST)

    Science.gov (United States)

    Ennico, Kimberly; Bendek, Eduardo A.; Lynch, Dana H.; Vassigh, Kenny K.; Young, Zion

    2016-07-01

    The Configurable Aperture Space Telescope, CAST, is a concept that provides access to a UV/visible-infrared wavelength sub-arcsecond imaging platform from space, something that will be in high demand after the retirement of the astronomy workhorse, the 2.4 meter diameter Hubble Space Telescope. CAST allows building large aperture telescopes based on small, compatible and low-cost segments mounted on autonomous cube-sized satellites. The concept merges existing technology (segmented telescope architecture) with emerging technology (smartly interconnected modular spacecraft, active optics, deployable structures). Requiring identical mirror segments, CAST's optical design is a spherical primary and secondary mirror telescope with modular multi-mirror correctors placed at the system focal plane. The design enables wide fields of view, up to as much as three degrees, while maintaining aperture growth and image performance requirements. We present a point design for the CAST concept based on a 0.6 meter diameter (3 x 3 segments) growing to a 2.6 meter diameter (13 x 13 segments) primary, with a fixed Rp=13,000 and Rs=8,750 mm curvature, f/22.4 and f/5.6, respectively. Its diffraction limited design uses a two arcminute field of view corrector with a 7.4 arcsec/mm platescale, and can support a range of platescales as fine as 0.01 arcsec/mm. Our paper summarizes CAST, presents a strawman optical design and requirements for the underlying modular spacecraft, highlights design flexibilities, and illustrates applications enabled by this new method in building space observatories.

  19. Catenary Action in Rebars Crossing a Casting Joint Loaded in Shear

    DEFF Research Database (Denmark)

    Sørensen, Jesper Harrild; Hoang, Linh Cao; Olesen, John Forbes

    2016-01-01

    Reinforcement crossing a casting joint loaded in shear exhibits catenary action as the shear displacement increases. The load carrying capacity of such a joint is in practice often calculated by use of empirical methods to account for shear friction effects or by a first order plastic analysis if...... and theory is found when reasonable material properties are assumed.......Reinforcement crossing a casting joint loaded in shear exhibits catenary action as the shear displacement increases. The load carrying capacity of such a joint is in practice often calculated by use of empirical methods to account for shear friction effects or by a first order plastic analysis...... if dowel action is included. The strength increase/reserve due to catenary action in the rebars is often neglected; however in some cases it may be necessary to utilize the effect in order to ensure overall structural robustness. This paper presents results of a study, where the increased shear capacity...

  20. The place of consumption in ecological economics

    DEFF Research Database (Denmark)

    Røpke, Inge; Reisch, Lucia A.

    2004-01-01

    Research concerning consumption in an environmental perspective has become very dynamic in recent years. Throughout the 1990s contributions have emerged from several different disciplines and approaches, and the research now covers a wide variety of topics. As ecological economics is open...... for considering all aspects of the interactions between humans, and the environment and simultaneously has the ambition of promoting transdisciplinary work, it is not surprising to see an increasing number of contributions on consumption and environment emerge at ecological economics conferences and in journals...... of the following is to give an idea of the disciplinary and methodological breadth and variety of research concerning consumption and environment, and to place ecological economic contributions in perspective....

  1. Eventful places in the 2011 movements

    DEFF Research Database (Denmark)

    Risager, Bjarke Skærlund

    Inspired by the Occupy movement, the Egyptian revolutionaries and other of the 2011 social movements, this paper investigates the relationship between social movement and place. Drawing on first-hand accounts from these movements, I argue that the relationship between movement and place is dialec...

  2. Influence of Refiner in ZA-12 Alloys During Centrifugal Casting Process

    Science.gov (United States)

    Jyothi, P. N.; Shailesh, Rao A.; Jagath, M. C.; Channakeshavalu, K.

    2014-05-01

    The behavior of the molten melt plays a predominant role in determining the quality cast product. In continuous casting, addition of refiner 1% (Al+Ti+B2) onto the molten metal increases its mechanical properties as a result of the nucleation within the process. In this article, the effect of refiners in the centrifugal casting process was studied. Eutectic ZA-12 alloys were taken for our experiment and cast at various rotational speeds (400 rpm, 600 rpm, and 800 rpm) with and without the addition of refiners. Rather than increase in the solidification rate as in continuous casting, these refiners diminish the solidification rate, which in turn forms an irregular-shaped cast tube. The microstructure and hardness for the entire cast specimen were discussed finally.

  3. Y-chromosomal insights into the genetic impact of the caste system in India.

    Science.gov (United States)

    Zerjal, Tatiana; Pandya, Arpita; Thangaraj, Kumarasamy; Ling, Edmund Y S; Kearley, Jennifer; Bertoneri, Stefania; Paracchini, Silvia; Singh, Lalji; Tyler-Smith, Chris

    2007-03-01

    The caste system has persisted in Indian Hindu society for around 3,500 years. Like the Y chromosome, caste is defined at birth, and males cannot change their caste. In order to investigate the genetic consequences of this system, we have analysed male-lineage variation in a sample of 227 Indian men of known caste, 141 from the Jaunpur district of Uttar Pradesh and 86 from the rest of India. We typed 131 Y-chromosomal binary markers and 16 microsatellites. We find striking evidence for male substructure: in particular, Brahmins and Kshatriyas (but not other castes) from Jaunpur each show low diversity and the predominance of a single distinct cluster of haplotypes. These findings confirm the genetic isolation and drift within the Jaunpur upper castes, which are likely to result from founder effects and social factors. In the other castes, there may be either larger effective population sizes, or less strict isolation, or both.

  4. In-situ surface hardening of cast iron by surface layer metallurgy

    Energy Technology Data Exchange (ETDEWEB)

    Fischer, Sebastian F., E-mail: s.fischer@gi.rwth-aachen.de [Foundry Institute, RWTH Aachen University, Intzestraße 5, 52072 Aachen (Germany); Muschna, Stefan, E-mail: smuschna@yahoo.de [Foundry Institute, RWTH Aachen University, Intzestraße 5, 52072 Aachen (Germany); Bührig-Polaczek, Andreas, E-mail: sekretariat@gi.rwth-aachen.de [Foundry Institute, RWTH Aachen University, Intzestraße 5, 52072 Aachen (Germany); Bünck, Matthias, E-mail: m.buenck@access-techcenter.de [Access e.V., Intzestraße 5, 52072 Aachen (Germany)

    2014-10-06

    Abrasive wear is a serious problem in many cast iron castings used in industry. To minimize failure and repair of these components, different strategies exist to improve their surface microhardness thus enhancing their wear resistance. However, most of these methods lead to very brittle and/or expensive castings. In the current work a new method for surface hardening is presented which utilizes surface layer metallurgy to generate in-situ a boron-enriched white cast iron surface layer with a high microhardness on a gray cast iron casting. To do this, sand molds are coated with a ferroboron suspension and cast with a cast iron melt. After solidification, a 100–900 µm thick layer of boron-enriched ledeburite is formed on the surface of the casting which produces an increase in the average microhardness from 284 HV{sub 0.1}±52 HV{sub 0.1} to 505 HV{sub 0.1}±87 HV{sub 0.1}. Analyses of the samples' core reveal a typical cast iron microstructure which leads to the conclusion that the coating mainly affects the castings' surface. By varying the grain size of the ferroboron powder in the coatings, it is shown that a powder size ≤100 µm is most suitable to create a boron-enriched ledeburite surface layer possessing high hardness values.

  5. Depth perception from moving cast shadow in macaque monkey.

    Science.gov (United States)

    Mizutani, Saneyuki; Usui, Nobuo; Yokota, Takanori; Mizusawa, Hidehiro; Taira, Masato; Katsuyama, Narumi

    2015-07-15

    In the present study, we investigate whether the macaque monkey can perceive motion in depth using a moving cast shadow. To accomplish this, we conducted two experiments. In the first experiment, an adult Japanese monkey was trained in a motion discrimination task in depth by binocular disparity. A square was presented on the display so that it appeared with a binocular disparity of 0.12 degrees (initial position), and moved toward (approaching) or away from (receding) the monkey for 1s. The monkey was trained to discriminate the approaching and receding motion of the square by GO/delayed GO-type responses. The monkey showed a significantly high accuracy rate in the task, and the performance was maintained when the position, color, and shape of the moving object were changed. In the next experiment, the change in the disparity was gradually decreased in the motion discrimination task. The results showed that the performance of the monkey declined as the distance of the approaching and receding motion of the square decreased from the initial position. However, when a moving cast shadow was added to the stimulus, the monkey responded to the motion in depth induced by the cast shadow in the same way as by binocular disparity; the reward was delivered randomly or given in all trials to prevent the learning of the 2D motion of the shadow in the frontal plane. These results suggest that the macaque monkey can perceive motion in depth using a moving cast shadow as well as using binocular disparity.

  6. Social marketing: its place in public health.

    Science.gov (United States)

    Ling, J C; Franklin, B A; Lindsteadt, J F; Gearon, S A

    1992-01-01

    This review of the public health role of social marketing begins by tracing the history of social marketing and noting that social marketing adopts the traditional marketing framework of product, price, place, and promotion and embraces several methods of commercial marketing as well as consumer research. However, no universally acknowledged definition exists. A review of the literature is divided into three time periods representing early theoretical development, the evaluation of experiences, and increasing acceptance. Concerns about social marketing are discussed in terms of ethics, disempowerment, and the commercialization of health information. Examples of social marketing are then provided from developing countries and are analyzed in groupings defined as tangible products, sustained health practices, and service utilization. Practitioners' views and concerns are also reviewed. The strengths of social marketing include knowledge of the audience, systematic use of qualitative methods, use of incentives, closer monitoring, strategic use of the mass media, realistic expectations, aspiring to high standards, and recognition of price. Weaknesses of social marketing include its time, money, and human requirements; the fact that marketing elements are missing (public health lacks the flexibility to adjust products and services to clients' interests and preferences); and the potential serious impact on the future of Public Service Announcements, which may die out because social marketers pay for air time. After placing social marketing in context with other practices designed to achieve social change, the review ends with the prediction that the public health role of social marketing is likely to increase. The World Health Organization's recent call for health promotion and the UN Children's Fund's social mobilization actions are provided as examples of this increased role. It is noted, however, that social marketing alone cannot solve public health problems.

  7. Safety Training: places available in October 2014

    CERN Multimedia

    2014-01-01

    There are places available in the forthcoming Safety courses. For updates and registrations, please refer to the Safety Training Catalogue. Safety Training, HSE Unit safety-training@cern.ch Title of the course EN Title of the course FR Date Hours Language Chemical Safety ATEX Habilitation - Level 2 Habilitation ATEX - Niveau 2 16-Oct-14 to 17-Oct-14 9:00 - 17:30 French Cryogenic Safety Cryogenic Safety - Fundamentals Sécurité Cryogénie - Fondamentaux 23-Oct-14 10:00 - 12:00 English Cryogenic Safety - Helium Transfer Sécurité Cryogénie - Transfert d'hélium 30-Oct-14 9:30 - 12:00 English Electrical Safety Habilitation Electrique - Electrician Low Voltage - Initial Habilitation électrique - Électricien basse tension - Initial 02-Oct-14 to 06-Oct-14 9:00 - 17:30 English 20-Oct-14 to 22-Oct-14 9:00 -...

  8. Early Functional Treatment and Modern Cast Making for Indications in Hand Surgery

    Directory of Open Access Journals (Sweden)

    S. Bohr

    2016-01-01

    Full Text Available Cast treatment can serve both as a nonsurgical treatment option and as a means for providing postoperative protection. However, with the duration of immobilization intervals, the benefits of cast treatment, especially in hand surgery, are at risk of being outweighed by undesired drawbacks such as joint stiffening and contracture formation. In order to minimize potential complications commonly associated with cast treatment, efforts to further improve cast making must attempt to reconcile two conflicting objectives: (1 to achieve stability and rigidity at the site of injury (e.g., fracture retention and (2 to allow free range of joint movement as early as possible. In addition, in order to assure patient compliance, modern cast treatments should aim to improve wearing-comfort of the cast. This paper describes modern cast designs for four common types hand injuries, with sample cases highlighting the clinical outcome of each treatment.

  9. Caste-, work-, and descent-based discrimination as a determinant of health in social epidemiology.

    Science.gov (United States)

    Patil, Rajan R

    2014-01-01

    Social epidemiology explores health in the context of broad social determinants of health, where the boundary lines between health and politics appear increasingly blurred. Social determinants of health such as caste, discrimination, and social exclusion are inherently political in nature, hence it becomes imperative to look at health through a broader perspective of political philosophy, ideology, and caste that imposes enormous obstacles to a person's full attainment of civil, political, economic, social, and cultural rights. Caste is descent based and hereditary in nature. It is a characteristic determined by one's birth into a particular caste, irrespective of the faith practiced by the individual. Caste denotes a system of rigid social stratification into ranked groups defined by descent and occupation. Under various caste systems throughout the world, caste divisions also dominate in housing, marriage, and general social interaction divisions that are reinforced through the practice and threat of social ostracism, economic boycotts, and even physical violence-all of which undermine health equality.

  10. Flow Induced segregation in full scale castings with SCC

    DEFF Research Database (Denmark)

    Thrane, Lars Nyholm; Stang, Henrik; Geiker, Mette Rica

    2007-01-01

    Though promising, pioneering work has been carried out with rheological characterization and numerical modelling of form filling with SCC, the approach is far from standard in the concrete industry and clearly the approach does not yet hold all the answers to relevant questions. In particular flow...... induced segregation is a major risk during casting and it is not yet clear how this phenomenon should be modelled. In this paper testing and numerical simulations of full-scale wall castings are compared. Two different SCCs and three different filling methods were applied resulting in different flow...... patterns during form filling. Results show that the flow patterns have a major influence on the risk of flow induced segregation and the surface finish of the hardened concrete. A hypothesis for the mechanism of flow induced segregation is put forth....

  11. Solid-particle erosion behavior of cast alloys used in the mining industry

    Science.gov (United States)

    Atapek, Ş. Hakan; Fidan, Sinan

    2015-12-01

    The erosive-wear response of five commercial ferrous-based cast alloys used for crushing was examined in this study. The microstructures of the alloys were modified to elucidate the effect of microstructural features on wear. Erosion tests were conducted using aluminum oxide particles (90-125 μm) at 70 m/s and a normal impact angle (90°). The worn surfaces were characterized by scanning electron microscopy and 3D non-contact laser profilometry. It is found that (i) a pearlitic structure exhibiting a greater plastic deformation than both bainitic and martensitic structures shows the greatest resistance to erosive wear at normal impact and (ii) the fracture characteristics of carbide and graphite particles plays an important role in determining the erosion wear behavior of the cast alloy matrices.

  12. Thermal Stresses in a Cylinder Block Casting Due to Coupled Thermal and Mechanical Effects

    Institute of Scientific and Technical Information of China (English)

    XU Yan; KANG Jinwu; HUANG Tianyou; HU Yongyi

    2008-01-01

    Thermal stress in castings results from nonuniform cooling. The thermal stress and the deforma-tion can change the casting and mold contact conditions which then alter the heat transfer between the cast-ing and the mold. The contact element method was used to study the interaction between a sand mold and a casting. The contact status was then fed back to the heat transfer analysis between the sand mold and the casting to re-evaluate the heat transfer coefficient based on the gap size or pressure between surfaces. The thermal and mechanical phenomena are then coupled in two directions. The method was applied to analyze stress in a stress frame specimen casting and a cylinder block. The results are more accurate than without consideration of the contact effects on the heat transfer.

  13. Castability of ductile iron in thin walled castings (TWDI

    Directory of Open Access Journals (Sweden)

    M. Górny

    2008-10-01

    Full Text Available In work it has been presented results of influence of pouring temperature (Tp and carbon equivalent (CE on castability of ductile iron in thin walled castings with wall thickness of 1, 2 and 3 mm, respectively. Analysis was done on ductile iron with carbon equivalent ranging from 4.30 to 5.00 and pouring temperature varied from 1400 to 1500 oC. It has been shown that a statistical liner relationship exists between wall thickness and castability. Influence of CE and Tp on castability of cast iron flowing through channel with wall thickness of 2 and 3 mm can be presented by means of correlation equations (L = f(CE, Tp. Statistical analysis shows that pouring temperature has much higher influence on castability in comparison with influence of carbon equivalent.

  14. Fluid Flow in Continuous Casting Mold with a Configured Nozzle

    Institute of Scientific and Technical Information of China (English)

    王镭; 沈厚发; 柳百成

    2004-01-01

    The influence of a configured nozzle on the turbulent fluid flow in a continuous casting mold was investigated using the simulation program Visual Cast, which used the finite difference method and the SIMPLER algorithm. CAD software was used to construct the complicated nozzle in the calculational region. The simulation accuracy was validated by comparison with the classic driven cavity flow problem. The simulation results agree well with water modeling experiments. The simulations show that the velocity distribution at the nozzle port is uneven and the jet faces downward more than the nozzle outlet. Simulations with a configured nozzle and the inlet velocity at the nozzle entrance give precise results and overcome the traditional difficulty in determining the nozzle outlet velocity.

  15. Contested Spaces. Meaningful Places. Contemporary Performances of Place and Belonging in Spain and Brazil

    Directory of Open Access Journals (Sweden)

    Maria J. C. Krom

    2009-12-01

    Full Text Available This essay aims to contribute to current anthropological debate on space and place, analysing in two instances of festival performance how, on the one hand the politics of appropriation of space contributes to the configuration of power relations, and how on the other hand, participants in these festivals engage individually and collectively with physical space(s to create places which they experience as meaningful in terms of identity and belonging.

  16. Safety Training: places available in May 2013

    CERN Multimedia

    Isabelle CUSATO, HSE Unit

    2013-01-01

    There are places available in the forthcoming Safety courses. For updates and registrations, please refer to the Safety Training Catalogue.   May 2013 (alphabetical order) Conduite de chariots élévateurs (driving of forklifts) 06-MAY-13 to 07-MAY-13, 8.30 – 17.30, in French with handouts in English Self Rescue Mask Training 02-MAY-13, 8.30 – 10.00, in English 02-MAY-13, 10.30 – 12.00, in English 07-MAY-13, 8.30 – 10.00, in French 07-MAY-13, 10.30 – 12.00, in English 14-MAY-13, 8.30 – 10.00, in French 14-MAY-13, 10.30 – 12.00, in French 16-MAY-13, 8.30 – 10.00, in English 16-MAY-13, 10.30 – 12.00, in English 21-MAY-13, 8.30 – 10.00, in French 21-MAY-13, 10.30 – 12.00, in French 23-MAY-13, 8.30 – 10.00, in English 23-MAY-13, 10.30 – 12.00, in English 28-MAY-13, 8.30 – 10.00, in French 28-MAY-13, 10.30 – 12.00, in French 30-MAY-1...

  17. Characterization of Solidification and Solid State Transformation in Duplex Cast Steel: Thermo-Calc Investigation

    Directory of Open Access Journals (Sweden)

    Z. Stradomski

    2007-07-01

    Full Text Available The paper presents a characteristic of solidification process and changes occurring in the solid state in a duplex cast steel. Theoretical chemical composition of individual phases, its changes during solidification and cooling after solidification and also changes in volume fractions of phases versus temperature have been determined. Theoretical results of Thermo-Calc analysis have been correlated with the microstructure of as-cast cast steel as well as with analysis of chemical composition of individual phases, carried out on a scanning microscope equipped with an EDS attachment. It has been shown that at the carbon content of 0.1% the enrichment of residual liquid phase with carbon results in a peritectic reaction, changing the ferritic solidification model typical for cast steels with low carbon content. In the case of solidification grain boundary areas enrichment with carbon, chromium and molybdenum there is a possibility of carbides precipitation already in the liquid state, what increases propensity for hot cracking and reduces the quality of castings produced. A correlation between theoretical composition of ferrite, austenite and M23C6 carbides, determined based on Thermo-Calc software, and their actual composition determined based on local analyses of chemical composition carried out on a scanning microscope has been shown. The volume fractions of ferrite, austenite and carbides determined using Thermo-Calc software show a strong correlation with actual fractions of those phases in the examined alloy’s structure. The chemical composition of ferrite, austenite and carbides determined using Thermo-Calc software does not show any more such strong correlation with the actual chemical composition of those phases determined based on local analyses of chemical composition carried out using a scanning microscope.

  18. Preparation of Plaster Moulage (Cast in Plastic Surgery patients

    Directory of Open Access Journals (Sweden)

    Rana R

    2003-01-01

    Full Text Available The purpose of this paper is to describe the technique of making casts using alginate compound for negative and dental stone plaster for positive impressions. With certain modifications a cast could be made of any part of the body and one can make a museum of interesting cases. Casts serve as useful teaching material especially in cleft lip and palate patients to study the effect of surgery on growth and development of the cleft lip-palate-nose complex in relation to the remaining face. It also helps in planning reconstruction in cases of facial defects, recording serial changes in multistage surgery, pre-operative and post-operative comparison as in rhinoplasty, ear reconstruction, hand etc; for comparing results before and after treatment in keloid and hypertrophic scars, fabrication of implants and preparation of prosthesis. In spite of newer modalities like 3-D imaging and stereolithography, the usefulness of this old technique in certain interesting cases can not be denied.

  19. Energy and resource efficiency in aluminium die casting

    CERN Document Server

    Heinemann, Tim

    2016-01-01

    This monograph provides a field-proven approach to analyze industrial production with a cross-company scope as well as regarding all hierarchical system levels of manufacturing enterprises. The book exemplifies this approach in the context of aluminum  die casting, and presents a set of measures which allow a 30 percent energy reduction along the value chain. The target audience primarily comprises researchers and experts in the field but the book may also be beneficial for graduate students.

  20. Safety Training: places available in February

    CERN Multimedia

    DGS Unit

    2012-01-01

    There are places available in the forthcoming Safety courses. For updates and registrations, please refer to the Safety Training Catalogue. FEBRUARY 2012 (alphabetical order) Conduite de Plates-Formes Elevatrices Mobiles de Personnel (PEMP) / Cherry-picker driving : 09-FEB-12 au 10-FEB-12, 08.00 – 17.30, in French (with possibility to have handouts in English) Magnetic Fields : 03-FEB-12, 9.30 – 12.00, in French Self-rescue mask : 02-FEB-12, 8.30 – 10.00, in French 02-FEB-12, 10.30 – 12.00, in English 07-FEB-12, 8.30 – 10.00, in French 07-FEB-12, 10.30 – 12.00, in English 14-FEB-12, 8.30 – 10.00, in French 14-FEB-12, 10.30 – 12.00, in English 16-FEB-12, 8.30 – 10.00, in French 16-FEB-12, 10.30 – 12.00, in English 21-FEB-12, 8.30 – 10.00, in French 21-FEB-12, 10.30 – 12.00, in English 28-FEB-12, 8.30 – 10.00, in French 28-FEB-12, 10.30 – 12.00, in English Radiologic...

  1. Monitoring metal-fill in a lost foam casting process.

    Science.gov (United States)

    Abdelrahman, Mohamed; Arulanantham, Jeanison Pradeep; Dinwiddie, Ralph; Walford, Graham; Vondra, Fred

    2006-10-01

    The lost foam casting (LFC) process is emerging as a reliable casting method. The metal-fill profile in LFC plays an important role among several factors that affect casting quality. The metal-fill profile is in turn affected by several factors. Several casting defects may result due to an improper metal-fill process. Hence, it becomes essential to characterize and control, if possible, the metal-fill process in LFC. This research presents instrumentation and a technique to monitor and characterize the metal-fill process. The characterization included the determination of the position of the metal front and the profile in which the metal fills up the foam pattern. The instrumentation included capacitive sensors. Each sensor is comprised of two electrodes whose capacitive coupling changes as the metal fills the foam pattern. Foundry tests were conducted to obtain the sensors' responses to the metal fill. Two such sensors were used in the foundry tests. Data representing the responses of these sensors during the metal-fill process were collected using a data acquisition system. A number of finite element electrostatic simulations were carried out to study the metal-fill process under conditions similar to those experienced in foundry tests. An artificial neural network was trained using the simulation data as inputs and the corresponding metal-fill profiles as outputs. The neural network was then used to infer the profile of the metal-fill during foundry tests. The results were verified by comparing the metal-fill profile inferred from the neural network to the actual metal-fill profile captured by an infrared camera used during the foundry tests. The match up between the inferred profiles and the infrared camera measurements was satisfactory, indicating that the developed technique provides a reliable and cost effective method to monitor the metal-fill profile in LFC.

  2. Safety Training: places available in March

    CERN Multimedia

    HSE Unit

    2012-01-01

    There are places available in the forthcoming Safety courses. For updates and registrations, please refer to the Safety Training Catalogue. MARCH 2012 (alphabetical order, titles of courses in the original language) Echafaudages, réception et conformité (Scaffolding, reception and conformity): From 29-FEB-12 to 02-MAR-12, 09.00 – 17.30, in French (in Domarin, dept. 38) Laser Users : 09-MAR-12, 09.00 – 12.30, in English Self-Rescue Mask training : 08-MAR-12, 08.30 – 10.00, in French 08-MAR-12, 10.30 – 12.00, in English 13-MAR-12, 08.30 – 10.00, in French 13-MAR-12, 10.30 – 12.00, in English 20-MAR-12, 08.30 – 10.00, in French 20-MAR-12, 10.30 – 12.00, in English 22-MAR-12, 08.30 – 10.00, in French 22-MAR-12, 10.30 – 12.00, , in English 27-MAR-12, 08.30 – 10.00, in French 27-MAR-12, 10.30 – 12.00, in English Habilitation électrique pour Electriciens en b...

  3. Safety Training: places available in January 2013

    CERN Multimedia

    Isabelle CUSATO, HSE Unit

    2012-01-01

    There are places available in the forthcoming Safety courses. For updates and registrations, please refer to the Safety Training Catalogue.   January 2013 (alphabetical order) Ergonomics - Applying ergonomic principles in the workplace 24-JAN-13 to 24-JAN-13, 9:00 – 12:00, in English Etre TSO au CERN 23-JAN-13 to 25-JAN-13, 9:00 – 17:30, in French Self-Rescue Mask training 08-JAN-13 to 08-JAN-13, 8:30 – 10:00, in French 08-JAN-13 to 08-JAN-13, 10:30 – 12:00, in French 10-JAN-13 to 10-JAN-13, 8:30 – 10:00, in English 10-JAN-13 to 10-JAN-13, 10:30 – 12:00, in English 15-JAN-13 to 15-JAN-13, 8:30 – 10:00, in French 15-JAN-13 to 15-JAN-13, 10:30 – 12:00, in French 17-JAN-13 to 17-JAN-13, 8:30 – 10:00, in English 17-JAN-13 to 17-JAN-13, 10:30 – 12:00, in English 22-JAN-13 to 22-JAN-13, 8:30 – 10:00, in French 22-JAN-13 to 22-JAN-13, 10:30 – 12:00, in French 24-JAN-13 to 24-JAN-13,...

  4. Safety Training: places available in April 2014

    CERN Multimedia

    Safety Training team, HSE Unit

    2014-01-01

    There are places available in the forthcoming Safety courses. For updates and registrations, please refer to the Safety Training Catalogue (see here).   April 2014 (alphabetical order) ATEX Habilitation - Level 2 03-APR-14 to 04-APR-14, 9.00 – 17.30, in French Cryogenic Safety - Level 1 10-APR-14, 10.00 – 12.00, in English Electrical Palett Truck – Driving 15-APR-14, 8.30 – 12.30, in French (hand-outs in English for non-French-speaking participants) Fire Extinguisher 09-APR-14, 10.30 – 12.00, in French 16-APR-14, 10.30 – 12.00, in English 23-APR-14, 10.30 – 12.00, in English First Aider - Level 1 – Initial 03-APR-14, 8.30 – 17.30, in French 10-APR-14, 8.30 – 17.30, in English 16-APR-14, 8.30 – 17.30, in English 24-APR-14, 8.30 – 17.30, in English First Aider - Level 1 – Refresher 17-APR-14, 8.30 – 12.30, in English 17-APR-14, 13.30 – 17.30, in...

  5. Optimization of Heat Treatment in Aspect of Production’s Costs Reducing and Improving of Casting Quality from Duplex Cast Steel

    Directory of Open Access Journals (Sweden)

    D. Dyja

    2007-07-01

    Full Text Available The paper determines possibilities of cost optimisation in the production of GX2CrNiMoCu25-6-3-3 type duplex cast steel castings through selection of appropriate solution heat treatment temperature, which value depends on the content of alloying elements. Metallographic analysis was carried out for as-cast and heat treated cast steel. Hardness and impact strength of the cast steel were determined, which were correlated with the volume fraction of phases determined by means of ImagePro computer image analyser. It has been shown that increased carbon content creates a need to use higher treatment temperatures, thereby increasing the production cost. With increasing carbon content the cast steel hardness after solution heat treatment increases, however, crack resistance decreases

  6. Safety Training: places available in October 2013

    CERN Document Server

    Isabelle CUSATO, HSE Unit

    2013-01-01

    There are places available in the forthcoming Safety courses. For updates and registrations, please refer to the Safety Training Catalogue.   October 2013 (alphabetical order) Habilitation ATEX niveau 1 (ATEX habilitation level 1) 08-OCT-13, 9.00 – 17.30, in French Conduite de plates-formes élévatrices mobiles de personnel (PEMP) (Driving cherry-pickers) 21-OCT-13 to 22-OCT-13, 08.30 – 17.30, in French with handouts in English Ergonomics - Applying ergonomic principles in the workplace 03-OCT-13, 9.00 – 12.00, in English Être TSO au CERN (Being a TSO at CERN) 29-OCT-13 to 31-OCT-13, 9.00 – 17.30, in French Self-Rescue Mask Training 01-OCT-13, 10.30 – 12.30, in French 03-OCT-13, 10.30 – 12.30, in English 04-OCT-13, 8.30 – 10.30, in English 08-OCT-13, 10.30 – 12.30, in French 09-OCT-13, 10.30 – 12.30, in English 15-OCT-13, 10.30 – 12.30, in French 17-OCT-13, 10.30...

  7. Observation of Nanometric Silicon Oxide Bifilms in a Water-Atomized Hypereutectic Cast Iron Powder

    Science.gov (United States)

    Boisvert, Mathieu; Christopherson, Denis; L'Espérance, Gilles

    2016-10-01

    This study investigated the reasons for the irregular structure of primary graphite nodules that were formed in a hypereutectic cast iron powder during water atomization. The graphite nodules contain a significant amount of micron-sized pores and multiple nanometric voids that formed from silicon oxide bifilms. The bifilms theory is often used to explain the mechanisms responsible for the presence of pores in castings. However, even if many results presented in the literature tend to corroborate the existence of bifilms, to this date, only indirect evidences of their existence were presented. The observations presented in this paper are the first to show the double-sided nature of these defects. These observations support the bifilms theory and give an explanation for the presence of porosities in castings. The bifilms were used as substrate for graphite growth during solidification. The irregular structure of the graphite nodules is a consequence of the rather random structure of the bifilms that were introduced in the melt as a result of turbulences on the surface of the melt during pouring. The confirmation of the existence of bifilms can contribute to the understanding of the mechanical properties of various metallic parts.

  8. Optimization of Mold Yield in MultiCavity Sand Castings

    Science.gov (United States)

    Shinde, Vasudev D.; Joshi, Durgesh; Ravi, B.; Narasimhan, K.

    2013-06-01

    The productivity of ductile iron foundries engaging in mass production of castings for the automobile and other engineering sectors depends on the number of cavities per mold. A denser packing of cavities, however, results in slower heat transfer from adjacent cavities, leading to delayed solidification, possible shrinkage defects, and lower mechanical properties. In this article, we propose a methodology to optimize mold yield by selecting the correct combination of the mold box size and the number of cavities based on solidification time and mold temperature. Simulation studies were carried out by modeling solid and hollow cube castings with different values of cavity-wall gap and finding the minimum value of the gap beyond which there is no change in casting solidification time. Then double-cavity molds were modeled with different values of cavity-cavity gap, and simulated to find the minimum value of gap. The simulation results were verified by melting and pouring ductile iron in green sand molds instrumented with thermocouples, and recording the temperature in mold at predetermined locations. The proposed approach can be employed to generate a technological database of minimum gaps for various combinations of part geometry, metal and process, which will be very useful to optimize the mold cavity layouts.

  9. ON MODELLING OF MICROSTRUCTURE FORMATION, LOCAL MECHANICAL PROPERTIES AND STRESS – STRAIN DEVELOPMENT IN ALUMINIUM CASTINGS

    DEFF Research Database (Denmark)

    Svensson, Ingvar; Seifeddine, Salem; Kotas, Petr

    2009-01-01

    inherently affects the component’s properties depending on design, metallurgy and casting method. The wall thickness influences the coarseness of the microstructure and the material will have properties depending on the local metallurgical and thermal histories. This is independent on the material, i.......e. whether the casting is based on cast iron- or aluminium-alloys. The distribution of local properties in a casting might vary substantially which makes it difficult to optimize the casting with good accuracy. Often, mechanical simulations of the load situation are based on the assumption that the cast...... product has constant material properties throughout the entire casting. Thus, if the microstructure is determined or predicted at a given point, it gives the possibility to calculate the local material behaviour more realistically. The paper shows modelling and simulation of microstructure formation...

  10. Safety Training: places available in February 2014

    CERN Document Server

    The Safety Training Team, HSE Unit

    2014-01-01

    There are places available in the forthcoming Safety courses. For updates and registrations, please refer to the Safety Training Catalogue (see here).   February 2014 (alphabetical order) ATEX Habilitation - Level 1 04-FEB-14, 9.00 – 17.30, in French Electrical Work - Lock-out 05-FEB-14, 13.30 – 17.30, in French Ergonomics – Office 06-FEB-14, 9.00 – 12.00, in English Fire Extinguisher 26-FEB-14, 10.30 – 12.00, in French 05-FEB-14, 10.30 – 12.00, in English First Aider - Level 1 – Initial 20-FEB-14, 8.30 – 17.30, in French First Aider - Refresher 06-FEB-14, 8.30 – 12.30, in French 06-FEB-14, 13.30 – 17.30, in French 13-FEB-14, 8.30 – 12.30, in English 13-FEB-14, 13.30 – 17.30, in English Habilitation électrique - Electrician Low Voltage – Initial 10-FEB-14 to 12-FEB-14, 9.00 – 17.30, in French Habilitation électrique - Electrician ...

  11. Safety Training: places available in January 2014

    CERN Document Server

    Safety Training Team, HSE Unit

    2014-01-01

    There are places available in the forthcoming Safety courses. For updates and registrations, please refer to the Safety Training Catalogue (see here).   January 2014 (alphabetical order) Confined space 28-JAN-14, 9.00 – 17.30, in French Ergonomics – Office 30-JAN-14, 9.00 – 12.00, in French Fire Extinguisher 08-JAN-14, 10.30 – 12.00, in French 24-JAN-14, 10.30 – 12.00, in English 31-JAN-14, 10.30 – 12.00, in French First Aider - Level 1 – Initial 16-JAN-14, 8.30 – 17.30, in French 30-JAN-14, 8.30 – 17.30, in French First Aider – Refresher 09-JAN-14, 8.30 – 12.30, in French 09-JAN-14, 13.30 – 17.30, in French Habilitation électrique - Electrician Low Voltage - Initial 22-JAN-14 au 24-JAN-14, 9.00 – 17.30, in English Habilitation électrique - Electrician Low and High Voltage - Initial 28-JAN-14 au 31-JAN-14, 9.00 – 17.30, in French ...

  12. Safety Training: places available in January 2014

    CERN Multimedia

    Safety Training Team, HSE Unit

    2013-01-01

    There are places available in the forthcoming Safety courses. For updates and registrations, please refer to the Safety Training Catalogue (see here).   January 2014 (alphabetical order) Confined space 28-JAN-14, 9.00 – 17.30, in French Ergonomics – Office 30-JAN-14, 9.00 – 12.00, in French Fire Extinguisher 08-JAN-14, 10.30 – 12.00, in French 24-JAN-14, 10.30 – 12.00, in English 31-JAN-14, 10.30 – 12.00, in French First Aider - Level 1 – Initial 16-JAN-14, 8.30 – 17.30, in French 30-JAN-14, 8.30 – 17.30, in French First Aider – Refresher 09-JAN-14, 8.30 – 12.30, in French 09-JAN-14, 13.30 – 17.30, in French Habilitation électrique - Electrician Low Voltage - Initial 22-JAN-14 au 24-JAN-14, 9.00 – 17.30, in English Habilitation électrique - Electrician Low and High Voltage - Initial 28-JAN-14 au 31-JAN-14, 9.00 – 17.30, in French ...

  13. An optimization of injecting system in die casting

    Directory of Open Access Journals (Sweden)

    Wei WU

    2005-05-01

    Full Text Available After many years of development, die casting technology of metallic materials has been matured. In this paper,the lower-support and its injecting system were created with commercial software. And then the simulation software FLOW3D was applied to study the flow behavior of the melt during injection filling process. Both temperature field and defect distribution were simulated. Based on these results, the better injecting system with two additional overflows wasadopted.

  14. FACTORS AFFECTING FORMING PRECISION IN PATTERNLESS CASTING MANUFACTURING

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    The patternless casting manufacturing(PCM) technique adopts a new method of double scanning which combines the principle of discreteness and deposition with the resin-bonded sand technique.Two main factors, the liquid penetration regularities in the space between particles and the shape and dimension of the agglomeration unit body, are studied qualitatively and quantitatively.This provides the theoretical basis for selecting the forming technical parameters.The experiments verify the analysis.

  15. An optimization of injecting system in die casting

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    After many years of development, die casting technology of metallic materials has been matured. In this paper,the lower-support and its injecting system were created with commercial software. And then the simulation software FLOW3D was applied to study the flow behavior of the melt during injection filling process. Both temperature field and defect distribution were simulated. Based on these results, the better injecting system with two additional overflows was adopted.

  16. Safety Training: places available in March 2014

    CERN Document Server

    Safety Training team, HSE Unit

    2014-01-01

    There are places available in the forthcoming Safety courses. For updates and registrations, please refer to the Safety Training Catalogue (see here).   March 2014 (alphabetical order) Ergonomics - Worksite and Workshop 24-MAR-14, 9.00 – 17.30, in French Fire Extinguisher 05-MAR-14, 10.30 – 12.00, in French 12-MAR-14, 8.30 – 10.00, in English 12-MAR-14, 10.30 – 12.00, in English First Aider - Level 1 – Initial 27-MAR-14, 8.30 – 17.30, in English First Aider – Refresher 20-MAR-14, 8.30 – 12.30, in French 20-MAR-14, 13.30 – 17.30, in French Habilitation électrique - Electrician Low Voltage – Initial 17-MAR-14 to 19-MAR-14, 9.00 – 17.30, in French 24-MAR-14 to 26-MAR-14, 9.00 – 17.30, in English Habilitation électrique - Electrician Low and High Voltage – Initial 18-MAR-14 to 21-MAR-14, 9.00 – 17.30, in English Habilitation &eacut...

  17. Effect of RE-Al-N on Structures and Properties of M2 Cast High Speed Steel

    Institute of Scientific and Technical Information of China (English)

    符寒光; 杜建铭; 蒋志强; 邢建东

    2003-01-01

    M2 cast high speed steel was inoculated by addition of rare earth(RE)-Al-N, network eutectic carbides were eliminated, matrix microstructures were refined and the segregation of tungsten and molybdenum elements was relieved. In the condition that the hardness does not decrease, impact toughness obviously increases. Quenching at 1180 ℃ and three-times tempering at 560 ℃, the hardness of M2 cast high speed steel is 65~66 HRC, and impact toughness reaches 21.3 J*cm- 2. Modified M2 cast high speed steel has excellent thermal fatigue resistance and high temperature wear resistance. Roller made in modified M2 cast high speed steel has excellent service effect when it is used in slit rolling mill of hot rolling bar mill.

  18. Safety Training: places available in September 2013

    CERN Multimedia

    Isabelle Cusato, HSE Unit

    2013-01-01

    There are places available in the forthcoming Safety courses. For updates and registrations, please refer to the Safety Training Catalogue. September 2013 (alphabetical order) Conduite de plates-formes élévatrices mobiles de personnel (PEMP) (Cherry-picker driving) 12-SEP-13 au 13-SEP-13, 8.30 – 17.30, in French with handouts in English Ergonomics - Applying ergonomic principles in the workplace 19-SEP-13, 9.00 – 12.00, in French Être TSO au CERN (Being TSO at CERN) 10-SEP-13 to 12-SEP-13, 8.30 – 17.30, in French Habilitation ATEX - niveau 2 (ATEX habilitation - level 2) 19-SEP-13 to 20-SEP-13, 9.00 – 17.30, in French Habilitation électrique personnel électricien basse tension (electrical habilitation for electricians in low voltage) 11-SEP-13 to 13-SEP-13, 9.00 – 17.30, in English 23-SEP-13 to 25-SEP-13, 9.00 – 17.30, in French Habilitation électrique personnel non &eacut...

  19. Safety Training: places available in June

    CERN Document Server

    GS Department

    2012-01-01

    There are places available in the forthcoming Safety courses. For updates and registrations, please refer to the Safety Training Catalogue. June 2012 (alphabetical order) Champs magnétiques 08-JUN-12, 09h30 – 12h00, en anglais Conduite de plates-formes élévatrices mobiles de personnel (PEMP) (Cherry-picker training) 11-JUN-12 to 12-JUN-12, 08.00 – 17.00, in French (with possibility to have the handouts in English) Ergonomics - Applying ergonomic principles in the workplace 14-JUN-12, 09.00 – 12.00, in French First Aiders - Basic Course 06-JUN-12 to 07-JUN-12, 08.00 – 17.00, in French (total : 1.5 days) First Aiders - Refresher Course 07-JUN-12, 13.00 – 17.00, in French 12-JUN-12, 08.00 – 12.00, in English 12-JUN-12, 13.00 – 17.00, in English Habilitation ATEX niveau 2 (ATEX certification –  level 2) 07-JUN-12 to 08-JUN-12, 9.00 – 17.30, in French Habilitation &eacut...

  20. Safety Training: places available in February 2013

    CERN Multimedia

    Isabelle CUSATO, HSE Unit

    2013-01-01

    There are places available in the forthcoming Safety courses. For updates and registrations, please refer to the Safety Training Catalogue.   February 2013 (alphabetical order) Noise - Understanding the risks 01-FEB-13, 10.00 – 12.30, in French Magnetic Fields 08-FEB-13, 9.00 – 11.30, in French Conduite de plates-formes élévatrices mobiles de personnel (PEMP) – Cherry-picker driving 18-FEB-13 to 19-FEB-13, 8.30 – 17.30, in French Self-Rescue Mask Training 05-FEB-13, 8.30 – 10.00, in French 05-FEB-13, 10.30 – 12.00, in French 12-FEB-13, 8.30 – 10.00, in French 12-FEB-13, 10.30 – 12.00, in French 14-FEB-13, 8.30 – 10.00, en anglais 14-FEB-13, 10.30 – 12.00, en anglais 19-FEB-13, 8.30 – 10.00, in French 19-FEB-13, 10.30 – 12.00, in French 21-FEB-13, 8.30 – 10.00, en anglais 21-FEB-13, 10.30 – 12.00, en anglais 26-FEB-13, 8.30 &ndash...