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1

Stress and accidental defect detection on rolling mill rolls  

International Nuclear Information System (INIS)

During the rolling mill process, rolls are submitted to high pressures that can lead to local decohesion or metallurgical changes. Both these cracks or softened areas must be detected as soon as they appear because of the risk of spalling, marks on the product, and mill wreck. These defects can be detected using the eddy current method, and particularly sensors specially developed for micro-defects detection. These sensors must be adapted to the environment of a roll grinding machine on which they must be installed. Users' schedule of conditions also require them to be attached to a wide range of eddy current generator and automatic computerized interpretation. Mill requirements for new high tech roll grades and quality lead to continuous development and improvement of the tools that will provide immediate 'go - no go' information. This paper is an update of these developments. (author)

2

Wear of hot rolling mill rolls: An overview  

Science.gov (United States)

Rolling is today one of the most important industrial processes because a greater volume of material is worked by rolling than by any other technique. Roll wear is a multiplex process where mechanical and thermal fatigue combines with impact, abrasion, adhesion and corrosion, which all depend on system interactions rather than material characteristics only. The situation is more complicated in section rolling because of the intricacy of roll geometry. Wear variables and modes are reviewed along with published methods and models used in the study and testing of roll wear. This paper reviews key aspects of roll wear control - roll material properties, roll pass design, and system factors such as temperature, loads and sliding velocity. An overview of roll materials is given including adamites, high Cr materials, high speed tool steels and compound rolls. Non-uniform wear, recognized as the most detrimental phenomenon in section rolling, can be controlled by roll pass design. This can be achieved by computer-aided graphical and statistical analyses of various pass series. Preliminary results obtained from pilot tests conducted using a two-disc hot wear rig and a scratch tester are discussed.

Spuzic, S.; Strafford, K. N.; Subramanian, C.; Savage, G.

1994-08-01

3

Structural causes of defects in a cast iron mill roll  

Directory of Open Access Journals (Sweden)

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.

J. Krawczyk

2008-07-01

4

Dimensional ranges and rolling efficiency in a tandem cold rolling mill  

Energy Technology Data Exchange (ETDEWEB)

In this work, physical models and a neural network theory have been combined in order to predict the properties of a steel strip and to optimise the process parameters in cold rolling. The prediction of the deformation resistance of the material and the friction parameter is based on the physical model presented by Bland, Ford and Ellis and artificial neural network computing (ANN). The accuracy of these models has been tested and proved by using a large amount of the measured data. With the aid of these models it has been shown that (a) the small change to the relative reduction distribution can have a clear effect upon the rolling efficiency, (b) the dimensional ranges of the tandem cold roll mill can be determined and optimised and (c) the possibility to cold roll a new product of new width, strength or thickness can be determined and the parameters of the tandem cold rolling process can be optimised. (orig.) 43 refs.

Larkiola, J.

1997-12-31

5

Inprovement in rolling procedure and steel plates finishing on the rolling mill 2800  

International Nuclear Information System (INIS)

Technology directed towards the increase of metal output and quality of production in the process of rolling and finishing of steel plates on the rolling mill 2800 has been elaborated. The slab end deformation in vertical stand with angular gauge of 60 deg has been applied. Minimal uneven gauge is established by work roll contouring. Special cuts of optimal form on the surface of roller breaking-down stand are used for removal of mill scale together with hydrocleaning at increasing pressure. Methods of line slitting of sheet edges are analyzed. The sheets of all types of steel with the thickness up to 40 mm may be successfully cut in plastic state at 600-900 deg C

6

Digital technology for radiometric thickness gages in rolling mills  

International Nuclear Information System (INIS)

In this paper a nuclear (Am-241, Sr-90) computer-controlled thicknessgerge is described, utilizing the digital technologies additionally for transmission and filtration of signals of the receiver for automatic computation of the calibration curves, automatic standardization over the gauge range and on-line digital diagnosis. This device works without contact and can be used in cold and hot rolling mills. (orig.)

7

Development of rolling mill for rectangular orthodontic wires production  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Purpose: In orthodontic treatments, wires of different metallic alloys are used for alignment, leveling, correction of the molar position, space closing, finish and retention. The purpose of the paper is the characteristics of austenitic stainless steel wires, with a square traverse section, which were produced using a rolling mill built for this purpose, are presented hereDesign/methodology/approach: With respect to finish and retention, these wires are responsible for adequate positioning o...

Totten, G. E.; Filho, A. I.; Gouve?a, C. A. R.; Neto, A.; Casteletti, L. C.

2007-01-01

8

Slip Line Field Solution for Second Pass in Lubricated 4-High Reversing Cold Rolling Sheet Mill  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The development of a possible slip line field (slf) for theoretical calculations of the deforming pressure (load) in a second pass of a lubricated cold rolling sheet mill and validation using values from an aluminium sheet rolling mill was done in this work. This will be relevant in the manufacturing industries providing an easy method for determining necessary applied rolling load. Experimental rolling was carried out to observe the shear lines in the deformation field. Construction of possi...

Oluwole, Oluleke O.; Olayinka Olaogun

2011-01-01

9

Optimize cold sector material flow of a steel rolling mill  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The steel production is a highly capital and energy intensive industry that due to recent raw materials’ price increase and lowered demand, it has been squeezed and forced to look more deeply on how to add value to the customer at lower operative costs. The project was carried out on site at the ArcelorMittal’s millin Esch-Belval, Luxembourg which comprises an integrated melt shop, continuous casting plant and the rolling mill with the objectives of proposing optimization rules for the co...

Baudet, Alvaro

2010-01-01

10

Strip/Foil Rolling Mill Stochastic Excitation Model and Its Stability  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Based on the stochastic rolling force data from aluminum hot strip tandem mill, the ARMA time series model and the stochastic excitation power spectral density (PSD) model are established, and the stochastic rolling forces excitation model is established by utilizing Levenberg-Marquardt combined with generalized global planning algorithm. A two dimensional stochastic nonlinear dynamical model of rolls is presented considering the stochastic factor of the rolling force. The Hamilton function i...

Baoyu Xu; Xudong Wang; Yilun Liu; Haichao Feng

2012-01-01

11

Optimization of a Heavy Continuous Rolling Mill System Via Simulation  

Directory of Open Access Journals (Sweden)

Full Text Available The objective of this study was to develop an integrated simulation model, which generates a set of optimizing alternatives for a heavy continuous rolling mill system in a full-scale steelmaking factory. The simulation approach enabled us to evaluate the performance of the existing system and pinpointed existing bottlenecks in workstations and production flow. Consequently, it generated a set of optimum production alternatives. Data related to process and operation times, repairs, maintenance and quality control were collected and analyzed systematically. The simulation model was modeled by Visual SLAM and Awesim simulation language. The results and structure of the computer simulation model were validated and verified against the actual system. Also, the results of the models were discussed and approved by the production managers. The distinct feature of the simulation model is three fold. First, it is integrated and considers detailed operations and activities of the Rolling Mill system. Furthermore, it is designed to be integrated with other workshops of the factory. Second, it locates the optimum solutions by a rule-based methodology. Finally, the model considers the Just-in-Time configuration of the line and is capable of answering all production and inventory issues.

Ali Azadeh

2006-01-01

12

REDESIGN OF THE LUBRICATION AND SEALING SYSTEM AT THE ROLLING MILL STAND BEARING  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The thesis presents a reconstruction of the sealing and lubrication device support cylinders rolling mill aluminium foil in the company Impol d.d. The objective function is the passage of lubricating oil present in the mill and back, and only this is also eliminated. In the introduction to the description of the company Impol and the process of rolling aluminium foil. Proceed with presentation of various techniques of sealing and lubrication used on the machines, with an emphasis on rolling. ...

S?turm, Sebastijan

2012-01-01

13

Force prediction in cold rolling mills by polynomial methods  

Directory of Open Access Journals (Sweden)

Full Text Available A method for steel and aluminium strip thickness control is provided including a new technique for predictive rolling force estimation method by statistic model based on polynomial techniques.

Nicu ROMAN

2007-12-01

14

Design, fabrication and performance analysis of a planetary roll mill for fine grinding  

Directory of Open Access Journals (Sweden)

Full Text Available Reducing milling cost in mineral processing is a problem that has defiled all serious attempts while milling still takes up to 60% of comminution cost. The planetary roll mill is a new innovation for faster and finer grinding. It is designed and fabricated with grinding rolls rotating in a number of arms inside a grinding sphere. A test run of the complete machine with crushed granite and sandstone shows that the machine grinds to fine consistency within a short period of time. A comparison of the products of the machine with that of a standard Denver Laboratory Ball Mill shows that the machine is about 30% more efficient than the ball mill in terms of duration of grinding to a particular size consistency. One advantage of the planetary roll mill is that is can be used as a ball mill if the need arises. It is therefore recommended that this mill be developed for both research and industrial uses.

Ajaka E. O.

2011-04-01

15

Design of Rolling State Observers for Application to Control of Thickness and Tension in Rolling Mills  

Digital Repository Infrastructure Vision for European Research (DRIVER)

This study focuses on the necessity of designing state observers to be used in controller synthesis for rolling processes. This is motivated by the fact that using several kinds of sensors for measuring all of process variables is technically and economically avoided. On the other hand, using exact measurement in feedback control systems could considerably improve the quality of products. In other word, there is a trade-off between high quality and the implementation limitations, managed here...

Koofigar, Hamid R.; Shahab Amelian

2011-01-01

16

A model-based predictive control scheme for steal rolling mills using neural networks  

Directory of Open Access Journals (Sweden)

Full Text Available A capital issue in roll-gap control for rolling mill plants is the difficulty to measure the output thickness without including time delays in the control loop. Time delays are a consequence of the possible locations for the output thickness sensor, which usually is located some distance away from the roll gap. In this work, a new model-based predictive control law is proposed. The new scheme is a neural network based predictive control structure which is applied to roll-gap control with outstanding results. It is shown that the neural network based predictive control permits to overcome the existing time delays in the system dynamics. The proposed scheme implements a virtual thickness sensor, which releases an accurate estimate of the actual output thickness. It is shown that the dynamic response of the rolling mill system can be substantially improved by using the proposed controller. Simulation results are presented to illustrate the controller performance.

J. M. Gálvez

2003-03-01

17

Rolling process simulation of a pair-crossed hot strip mill  

International Nuclear Information System (INIS)

Process simulation can help optimize the operating parameters aiming to improve the quality of rolled products. In this paper, software in Visual Basic language is developed to simulate the hot rolling process of a pair-crossed mill. The strip temperature is calculated by considering air cooling, water cooling, heat generation and conduction.The production parameters including rolling speeds, resistance to deformation, rolling forces, drive torques and powers are evaluated by mathematical models and their parameter identification support tools. The deformation of roll stack is calculated by influential function method. The roll temperature and expansion are calculated by finite differential method, and the roll wear is described by empirical formula. Based on these calculations as well as the effect of heredity is taken into account, the strip crown and flatness then can be obtained. The results show that the simulation software has friendly user interface, high accuracy and practicability. It can be served as a basis for the mill design and optimization of process parameters to acquire high quality of hot rolled strip. (author)

18

Rolling process simulation of a pair-crossed hot strip mill  

Energy Technology Data Exchange (ETDEWEB)

Process simulation can help optimize the operating parameters aiming to improve the quality of rolled products. In this paper, software in Visual Basic language is developed to simulate the hot rolling process of a pair-crossed mill. The strip temperature is calculated by considering air cooling, water cooling, heat generation and conduction.The production parameters including rolling speeds, resistance to deformation, rolling forces, drive torques and powers are evaluated by mathematical models and their parameter identification support tools. The deformation of roll stack is calculated by influential function method. The roll temperature and expansion are calculated by finite differential method, and the roll wear is described by empirical formula. Based on these calculations as well as the effect of heredity is taken into account, the strip crown and flatness then can be obtained. The results show that the simulation software has friendly user interface, high accuracy and practicability. It can be served as a basis for the mill design and optimization of process parameters to acquire high quality of hot rolled strip. (author)

Chen Shaojie; Xu Jianzhong; Liu Xianghua; Wang Guodong [Northeastern Univ., State Key Lab of Rolling and Automation, Shenyang City (China)

2000-07-01

19

Design, fabrication and performance analysis of a planetary roll mill for fine grinding  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Reducing milling cost in mineral processing is a problem that has defiled all serious attempts while milling still takes up to 60% of comminution cost. The planetary roll mill is a new innovation for faster and finer grinding. It is designed and fabricated with grinding rolls rotating in a number of arms inside a grinding sphere. A test run of the complete machine with crushed granite and sandstone shows that the machine grinds to fine consistency within a short period of time. A comparison o...

Ajaka E. O.; Akinbinu V. A.

2011-01-01

20

Regulation of the Heating Furnace in Tube Rolling Mill  

Directory of Open Access Journals (Sweden)

Full Text Available The rolling of tube requires homogeneous heating along the tube. In steel work the difference along tube was sometimes 80 °C. The reasons for bad homogeneousness of heating were analyzed by a simulation model of heating furnace. Then the proposal was made for a new control system and also the proposal for reconstruction of furnace. In this contribution also a description of some ways for improvement of heating was made. The main contribution is the proposal of an adaptive system

Kostúr, K.

2006-01-01

 
 
 
 
21

Regulation of the Heating Furnace in Tube Rolling Mill  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The rolling of tube requires homogeneous heating along the tube. In steel work the difference along tube was sometimes 80 °C. The reasons for bad homogeneousness of heating were analyzed by a simulation model of heating furnace. Then the proposal was made for a new control system and also the proposal for reconstruction of furnace. In this contribution also a description of some ways for improvement of heating was made. The main contribution is the proposal of an adaptive system

Kostu?r, K.

2006-01-01

22

Specific features related to pulverizing wet coals in a roll mill  

Science.gov (United States)

Results from a calculation and experimental study of pulverizing wet brown coal in a roll mill are presented. The influence of moisture content in coal, types of grinding rollers, and effectiveness of separating the pulverization products in the separator on the mill output is estimated.

Shuvalov, S. I.; Mikheev, G. G.

2010-08-01

23

High Temperature Thermal Expansion and Elastic Modulus of Steels Used in Mill Rolls  

Science.gov (United States)

The high temperature thermal expansion coefficient (TEC) and elastic modulus of five steels used in mill rolls production were investigated by dilatometer and impulse excitation techniques (IET). The measurements were provided at heating from room temperature till temperatures of about 1000 °C and subsequent cooling. The obtained data were attributed to the properties of predominating phases (austenite, martensite, pearlite, and bainite). The TEC and elastic modulus of corresponding phases were similar for all investigated steels despite the difference in their chemical composition. The steels with a chromium content of 2.95 wt.% and more show enhanced ability to quench hardening. This is an important prerequisite for production of high quality mill rolls.

Laptev, Alexander; Baufeld, Bernd; Swarnakar, Akhilesh Kumar; Zakharchuk, Stanislav; van der Biest, Omer

2012-02-01

24

Extended Kalman Filter Based Neural Networks Controller For Hot Strip Rolling mill  

International Nuclear Information System (INIS)

The present paper deals with the application of an Extended Kalman filter based adaptive Neural-Network control scheme to improve the performance of a hot strip rolling mill. The suggested Neural Network model was implemented using Bayesian Evidence based training algorithm. The control input was estimated iteratively by an on-line extended Kalman filter updating scheme basing on the inversion of the learned neural networks model. The performance of the controller is evaluated using an accurate model estimated from real rolling mill input/output data, and the usefulness of the suggested method is proved

25

Rolling Robot  

Science.gov (United States)

Proposed rolling robot routinely traverses rough terrain, clearing rocks as high as 1 m. Climbs steps 1 m high and spans ditches 2.3 m wide. Simple but rugged semiautonomous rover has large wheels and articulated body. With combined yaw, roll, and four-wheel drive, robot crawls slowly to pass over soft or sandy terrain. Senses terrain along corridor, chooses path to avoid insurmountable obstacles, and monitors state of vehicle for unexpected hazards.

Larimer, Stanley J.; Lisec, Thomas R.; Spiessbach, Andrew J.

1990-01-01

26

A model-based predictive control scheme for steal rolling mills using neural networks  

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: English Abstract in english A capital issue in roll-gap control for rolling mill plants is the difficulty to measure the output thickness without including time delays in the control loop. Time delays are a consequence of the possible locations for the output thickness sensor, which usually is located some distance away from t [...] he roll gap. In this work, a new model-based predictive control law is proposed. The new scheme is a neural network based predictive control structure which is applied to roll-gap control with outstanding results. It is shown that the neural network based predictive control permits to overcome the existing time delays in the system dynamics. The proposed scheme implements a virtual thickness sensor, which releases an accurate estimate of the actual output thickness. It is shown that the dynamic response of the rolling mill system can be substantially improved by using the proposed controller. Simulation results are presented to illustrate the controller performance.

J. M., Gálvez; Luis E., Zárate; H., Helman.

2003-03-01

27

Research on Single-Side Long Edge of Hot Rolled Strip Caused by Asymmetrical Stiffness of Mill Stand  

Directory of Open Access Journals (Sweden)

Full Text Available To analyze and solve the problem of single-side long edge of hot rolled strip in certain domestic factory, the asymmetrical deformation of rolls and strip in asymmetrical stiffness mill stand based on slit beam model, the strip profile and rolling force distribution at the exit of asymmetric stiffness stand mill were calculated using influence function method. Considering the character of in-site equipment and technology, a scheme of adjusting load distribution in finishing mill was made and the experiment was applied. Comparison of strip profile between new load distribution and the old one shows that the method can solve single-side long edge problem well.

Dian-Yao Gong

2011-09-01

28

Mechanism of Oxidation of Austenitic Stainless Steels under Conditions of Hot Rolling in Steckel Mills  

Science.gov (United States)

The development of oxide scales on hot-rolled austenitic stainless steels under conditions imposed by the industrial Steckel Mill operation introduces particular characteristics that impact downstream on the surface quality of the hot-rolled strip product. In this research, the development of these particular surface structures were studied on 302 austenitic stainless steel by means of laboratory process simulation involving mechanical deformation in a multipass hot rolling schedule and long interpass time inside equalizing furnaces. Surface analysis using a set of complementary techniques that included field emission gun scanning electron microscopy (FEG-SEM), energy-dispersive spectroscopy (EDS), X-ray diffraction (XRD), and glow discharge optical spectroscopy (GDOS) provided a full characterization of the resulting surface structures. These structures consisted in multiple oxide scale and metal layers that were developed after each rolling pass and heavily modified by the following rolling operation establishing a single repetitive mechanism of surface development. The mechanism of formation of these complex multilayer surface structures has been fully determined as being associated with a cyclic oxidation pattern involving successive stages of protective oxidation, chemical breakaway, and the progress of duplex oxidation.

Cobo, S. J.; Palmiere, E. J.; Rainforth, W. M.

2008-10-01

29

Physical modelling of plastic deformation conditions for the rolling proces of AZ31 bars in a three high skew rolling mill  

Directory of Open Access Journals (Sweden)

Full Text Available The article presents results of the research concerning the physical modeling of plastic working of AZ31 magnesium alloy using two research methods. These studies were conducted using a metallurgical process simulator and torsional plastometer. The research was done for temperature range 200 ÷ 400 °C and strain rate from 0,1 to 20,0 s-1, depending on the testing method. The results allow to determine the coefficients in yield equation needed for the numerical research. Moreover the most advantageous temperature - velocity conditions to realize the process of bars rolling in three high skew rolling mill can be determined.

A. Gryc

2014-10-01

30

Effect of powder milling on mechanical properties of hot-pressed and hot-rolled Cu–Cr–Nb alloy  

International Nuclear Information System (INIS)

Highlights: •Milled powder enhances sintering and mechanical properties after hot pressing. •Hot-rolling of hot-pressed samples made from milled powder enhances ductility. •Pore size and number of pores decreases after hot-rolling. -- Abstract: The present study is on the effect of mechanical milling of gas-atomized powders on mechanical properties of the hot-pressed and subsequently hot-rolled Cu–8 at% Cr–4 at% Nb alloy with a microstructure consisting of pure copper matrix hardened by intermetallic Cr2Nb precipitates. The mechanically milled powders result in lower sintering temperature during hot pressing compared to the atomized powders. The hot-pressed samples made from the milled powder exhibit significantly higher hardness and tensile strength, but lower ductility and electrical conductivity compared to that made from the un-milled gas-atomized powders. The hot rolling results in marginal increase in strength, but significant increase in ductility compared to the hot-pressed alloy for both the milled and atomized powders and it is attributed to the decrease in size of the pores and amount of porosities after hot rolling

31

Effect of powder milling on mechanical properties of hot-pressed and hot-rolled Cu–Cr–Nb alloy  

Energy Technology Data Exchange (ETDEWEB)

Highlights: •Milled powder enhances sintering and mechanical properties after hot pressing. •Hot-rolling of hot-pressed samples made from milled powder enhances ductility. •Pore size and number of pores decreases after hot-rolling. -- Abstract: The present study is on the effect of mechanical milling of gas-atomized powders on mechanical properties of the hot-pressed and subsequently hot-rolled Cu–8 at% Cr–4 at% Nb alloy with a microstructure consisting of pure copper matrix hardened by intermetallic Cr{sub 2}Nb precipitates. The mechanically milled powders result in lower sintering temperature during hot pressing compared to the atomized powders. The hot-pressed samples made from the milled powder exhibit significantly higher hardness and tensile strength, but lower ductility and electrical conductivity compared to that made from the un-milled gas-atomized powders. The hot rolling results in marginal increase in strength, but significant increase in ductility compared to the hot-pressed alloy for both the milled and atomized powders and it is attributed to the decrease in size of the pores and amount of porosities after hot rolling.

Shukla, A.K.; Narayana Murty, S.V.S.; Suresh Kumar, R. [Materials and Metallurgy Group, Vikram Sarabhai Space Centre, Trivandrum 695 022 (India); Mondal, K., E-mail: kallol@iitk.ac.in [Department of Materials Science and Engineering, Indian Institute of Technology Kanpur, Kanpur 208 016 (India)

2013-12-15

32

Validation of a 3-D, Thermo-Mechanically Coupled Model for Multi-Pass Rolling in a Reversing Mill  

Energy Technology Data Exchange (ETDEWEB)

A three dimensional numerical model simulating multi-pass, hot rolling on a reversing mill has been developed to analyze deformation patterns and shape changes of a rolled ingot. Validation simulations through 15 passes with an 86% reduction have been performed using the thermo-mechanically coupled model to track the evolution of the deformed ingot geometry. The heat transfer coefficient for thermal conduction between the rolls and slab has been estimated in accordance with experimental data, and heat transfer to the air and coolant outside of the roll bite is included. A hyperbolic sine model using the Zener-Hollomon parameter is used to capture the temperature and strain rate dependence of the aluminum alloy. A Coulomb friction model with a flow strength dependent maximum limit on the interfacial shear stress was employed between the rolls and ingot. Results of validation simulations and comparisons with experiments focusing on the ingot shape evolution are discussed.

Rhee, M; Wang, P; Li, M; Becker, R

2004-01-30

33

Finite elements method (FEM simulation based prediction of deformation and temperature at rolling of tubes on a pilgrim mill  

Directory of Open Access Journals (Sweden)

Full Text Available 3D - FEM simulation was used as an efficient tool for description of stress-deformation thermal field at rolling of tubes on a pilgrim mill. The monitored objectives comprised also behaviour of working tools at this rolling. This paper assumes rolling of already pierced thick-walled blank, which passes through the pilgrim stand at simultaneous reduction of thickness of inside and outside diameters at the expense of elongation of initial length. Main attention is focused on the mentioned parameters with respect to various conditions of rolling, such as different heat transfer, different friction or different distance of insertion of the rolled product into the gauge. The input data used at simulation were derived from real conditions of tubemaking.

R. Kocich

2009-10-01

34

Feasibility of TiBN PVD Coating for Mill Rolls - Laboratory Testing of Anti-adhesive and Fatigue Resistance Properties  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The ceramic coatings deposited by Physical Vapour Deposition (PVD) are known for their high hardness. They offer a wide variety of friction coefficients. They have been used for a number of years for the coating of cutting tools; they have shown high efficiency in this field. Considering this, some of these coatings might prove efficient in the field of metal rolling. Yet to the best of the authors' knowledge, they have never been used industrially for rolling mill rolls. TiBN is one of the P...

Ould, Choumad; Badiche, Xavier; Montmitonnet, Pierre; Gachon, Yves

2011-01-01

35

The technology of production of high-strength, cold resistant weldable steel on wide-strip rolling mill  

International Nuclear Information System (INIS)

Regularities of influence of technological rolling parameters on wide-strip rolling mill on structure and mechanical characteristics of low-carbon steel of St3sp type were established. Possibility of sufficient growth of strength and cold resistance of strips, produced by hot working, as compared to traditional technology is shown. This is achieved by grain refinement and formation of subgrain structure in ferrite

36

Choice of technology for speed measurement in a cold rolling mill  

Digital Repository Infrastructure Vision for European Research (DRIVER)

An often encountered problem when implementing a mass flow regulator in a rolling mill is the one with measurement of speed. The most widely used solution is to fit a pulse counter to a wheel that is in contact with the strip. Common problems with this design are for instance scratch marks on the strip and problems with the flatness measuring system.  One way of circumventing the aforementioned problems would be a non-contact measuring system. The market of today only offers systems based on...

O?ling, Martin

2013-01-01

37

Effect of rolling parameters on the properties of Al-Fe-V sheet rolled on an experimental mill  

International Nuclear Information System (INIS)

In recent years, interest in high temperature aluminum alloys has increased. However, nearly all the data available is for simple extrusions. This paper looks at the properties of sheet made from a rapidly solidified Al-10Fe-2.5V-2Si alloy. The sheet is made by direct forging followed by hot rolling, this is readily scalable, so allowing the production of large sheet. The room temperature strength and fracture toughness of the sheet are comparable to those of 2014-T6. The high temperature strength, specific stiffness and corrosion resistance are excellent. Recently, improved thermomechanical processing and new alloys have allowed higher strengths and fracture toughness values to be obtained

38

Cross Shear Roll Bonding  

DEFF Research Database (Denmark)

The present paper describes an investigation of roll bonding an AlZn alloy to mild steel. Application of cross shear roll bonding, where the two equal sized rolls run with different peripheral speed, is shown to give better bond strength than conventional roll bonding. Improvements of up to 20-23% in bond strength are found and full bond strength is obtained at a reduction of 50% whereas 65% is required in case of conventional roll bonding. Pseudo cross shear roll bonding, where the cross shear effect is obtained by running two equal sized rolls with different speed, gives the same results.

Bay, Niels; Bjerregaard, Henrik

1994-01-01

39

Spray rolling aluminum alloy strip  

Energy Technology Data Exchange (ETDEWEB)

Spray rolling combines spray forming with twin-roll casting to process metal flat products. It consists of atomizing molten metal with a high velocity inert gas, cooling the resultant droplets in flight and directing the spray between mill rolls. In-flight convection heat transfer from atomized droplets teams with conductive cooling at the rolls to rapidly remove the alloy's latent heat. Hot deformation of the semi-solid material in the rolls results in fully consolidated, rapidly solidified product. While similar in some ways to twin-roll casting, spray rolling has the advantage of being able to process alloys with broad freezing ranges at high production rates. This paper describes the process and summarizes microstructure and tensile properties of spray-rolled 2124 and 7050 aluminum alloy strips. A Lagrangian/Eulerian poly-dispersed spray flight and deposition model is described that provides some insight into the development of the spray rolling process. This spray model follows droplets during flight toward the rolls, through impact and spreading, and includes oxide film formation and breakup when relevant.

McHugh, Kevin M.; Delplanque, J.-P.; Johnson, S.B.; Lavernia, E.J.; Zhou, Y.; Lin, Y

2004-10-10

40

Spray rolling aluminum alloy strip  

International Nuclear Information System (INIS)

Spray rolling combines spray forming with twin-roll casting to process metal flat products. It consists of atomizing molten metal with a high velocity inert gas, cooling the resultant droplets in flight and directing the spray between mill rolls. In-flight convection heat transfer from atomized droplets teams with conductive cooling at the rolls to rapidly remove the alloy's latent heat. Hot deformation of the semi-solid material in the rolls results in fully consolidated, rapidly solidified product. While similar in some ways to twin-roll casting, spray rolling has the advantage of being able to process alloys with broad freezing ranges at high production rates. This paper describes the process and summarizes microstructure and tensile properties of spray-rolled 2124 and 7050 aluminum alloy strips. A Lagrangian/Eulerian poly-dispersed spray flight and deposition model is described that provides some insight into the development of the spray rolling process. This spray model follows droplets during flight toward the rolls, through impact and spreading, and includes oxide film formation and breakup when relevant

 
 
 
 
41

Controlled rolling of profiles  

International Nuclear Information System (INIS)

The effect is investigated of various temperatures and deformation rates in the course of rolling of steels, of the 40Kh steel in particular, upon the power rating and the energy requirements, the roll wear and mechanical properties of finished rolled stock. It is found that a lowering of the rolling temperature to 950-850 deg C has improved the properties of the finished rolled stock (greater strength without reducing the plasticity)

42

Set of automatic nondestructive testing means for the quality control of pipes in production line of '140' rolling mill  

International Nuclear Information System (INIS)

Devices and installations are described forming a system of subsidiary mechanical equipment and means of automatization for testing hot-rolled ferromagnetic steel pipes in the finishing line of ''140'' pipe-rolling mill. The main features of the system are as follows: it is equipped with automatic control devices which supply objective information on the quality of the pipes; the non-destructive test equipment is automatic, thus rapid and reliable; auxiliary joints and devices are unificated, so that the separate stages of control can be quickly re-organized. A computer collects and stores information on tested pipes of the rolled lot and can supply it type-written. Computer-treated results of tests during a certain period, if analysed with regard for smelting and rolling technology, may be used as technological advice on improvement of production and may probably provide for savings on steel deformation processes

43

Neural compensation and modelling of a hot strip rolling mill using radial basis function  

Scientific Electronic Library Online (English)

Full Text Available SciELO Argentina | Language: English Abstract in english In this paper a Neural Compensation Strategy for a hot rolling mill process is proposed. The target of this work is to built a RBF-NN compensation approximation for the classical force feed forward and speed controller. A strategy based on neural networks is proposed here, because they are capable o [...] f modelling many nonlinear systems and their neural control via RBF-NN approximation. Simulations demonstrate that the proposed solution deals with disturbances and modeling errors in a better way than classic solutions do. The analysis of the RBF-NN approximation error on the control errors is included, and control system performance is verified through simulations.

F.G., Rossomando; J., Denti F; A., Vigliocco.

2011-07-01

44

Transport, mixing and stretching in a chaotic Stokes flow: The two-roll mill  

International Nuclear Information System (INIS)

We present the outline and preliminary results of an analytical and numerical study of transport, mixing, and stretching in a chaotic Stokes' flow in a two-roll mill apparatus. We use the theory of dynamical systems to describe the rich behavior and structure exhibited by these flows. The main features are the homoclinic tangle which functions as the backbone of the chaotic mixing region, the Smale horseshoe, and the island chains. We then use our detailed knowledge of these structures to develop a theory of transport and stretching of fluid in the chaotic regime. In particular, we show how a specific set of tools for adiabatic chaos- the adiabatic Melnikov function lobe area and flux computations and the adiabatic switching method is ideally suited to develop this theory of transport, mixing and stretching in time-dependent two-dimensional Stokes' flows. 19 refs., 8 figs

45

Increasing efficiency of cold rolling of corrosion resistant steel at mismatching roll velocities. [12Kh18N10T steel  

Energy Technology Data Exchange (ETDEWEB)

On the example of 12Kh18N10T steel rolling it is shown that 7-10% mismatching roll velocities raise the rolling efficiency, increase productivity and technological abilities of four-high mills at production of cold-rolled sheets. Scheme of the system of roll velocities mismatching control at asymmetrical rolling is presented. The comparative conditions of symmetrical and asymmetrical rolling of 0.8 x 1030 mm sheets from 12Kh18N10T steel are given.

Agishev, L.A.; Grishkov, A.I.; Fisher, A.R.; Frolov, G.I.; Kolesnikov, N.A. (Tsentral' nyj Nauchno-Issledovatel' skij Inst. Chernoj Metallurgii, Moscow (USSR))

1983-01-01

46

Improving Thermal Efficiency Of Push Type Furnace In A Hot Re-Rolling Steel Mill By Direct Method : Case Study  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Rolling is the process of reducing the thickness or changing the cross-section of a long work-piece by compressive forces applied through a set of rolls. Rolling accounts for about 90% of all metals produced by metalworking processes. The purpose of Rolling is to convert larger sections into smaller sections, which can be used directly in as rolled state or as stock for working through other processes. As a result of rolling, the coarse structure of cast in...

Jeetendra Mohan Khare, Sandip Kumar Mishra

2013-01-01

47

Rolling of rods of tungsten alloyed with lanthanum  

International Nuclear Information System (INIS)

Particularities of rolling process for rods of tungsten doped alloys and the design of test-commercial rolling mill of the MK-210 type are considered. The new process using rolling mills with four-roll passes permits to manufacture products with the uniformly developed structure and high surface quality. The yield of suitable products using a wire with 1.5-2.0 mm diameter produced of rolled billets is 15% higher than that of the mill one

48

Computation of Rolling Stand Parameters by Genetic Algorithm  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Mathematical model of rolling process is used at cold mill rolling on tandemmills in metallurgy. The model goal is to analyse rolling process according to process datameasured on the mill and get immeasurable variables necessary for rolling control andoptimal mill pre-set for next rolled coil. The values obtained by model are used asreferences for superimposed technology controllers (thickness, speed, tension, etc.) as well.Considering wide steel strip assortment (different initial and final ...

František ?urovský; Ladislav Zboray; Želmíra Ferková

2008-01-01

49

Study on Online Analysis of Transfer Function of Variable-Speed Rolling Mill Motor with Shaft Torsional Vibration Systems  

Science.gov (United States)

The torsional vibration between metal rolling rolls and a rolling mill motor, may occur in recent days, as a result of higher speed response adjustment for variable speed rolling mill motor drive system. Issues in this paper are focused on excess acceleration value, in tangential direction of the mill motor rotor, which is caused by the motor shaft torsional resonance at the white noise signal superposition to the speed reference signal of the motor drive system for the online transfer function analysis. As a result of the acceleration analysis, the acceleration values in “G” (Relative acceleration value on the basis of Gravity) can be plotted on “Bode-Diagram”, which is namely frequency response for the speed signal amplitude transmission ratio. In addition, relation between the white noise amplitude reduction and the transfer function analysis accuracy deterioration is also examined, in this paper. As the amplitude of the white noise decreases, the analysis error increases because of the reduction in the resolution when the amplitude of the white noise signal is small.

Tamaoki, Toshifumi; Takanezawa, Makoto; Kimoto, Masanori; Morita, Noboru; Hoshino, Takeo; Hashizume, Kenji

50

Finite element analysis of deflection of rolls and its correction by providing camber on rolls  

Directory of Open Access Journals (Sweden)

Full Text Available Rolling process is a key step in the production of flat steel products. Because of automation commonly implemented in flat product rolling mills, the products should meet the requirements of tight tolerances. one of the major defects observed in the rolling process is flatness and lack of attainment of the desired surface profile due to deflection of the rolls. The spatial shape and dimensions of the roll gap are influenced by the elastic deformation of all parts of the rolling stand equipment affected by the roll pressure. The current study aims to determine the variation of the deflection in rolls in a two high mill with varying percentage reduction of the sheet i.e, 20%, 25% and 30% on annealed and non-annealed IF steel sheet and analyzing possible solutions to reduce the elastic deflection of rolls with special emphasis on cambering and modelling of the same in Abaqus CAE.

Vijay Gautam

2013-10-01

51

Planejamento e controle da produção de cilindros para laminação: um estudo de caso quantitativo / Production management of rolling mill rolls: a quantitative study case  

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: Portuguese Abstract in portuguese Este trabalho apresenta um modelo de otimização-simulação aplicado em um estudo de caso real no setor de cilindros para laminação de uma siderúrgica, buscando melhorar o gerenciamento da área/equipamento gargalo da linha de produção. A simulação atuou em conjunto com um modelo de otimização da progr [...] amação linear inteira (PLI) para melhorar o atendimento de prazo junto aos clientes em uma produção não seriada. Como resultado deste procedimento combinado da PLI e simulação, o processo produtivo foi otimizado e as filas de espera e o lead-time foram reduzidos, melhorando o atendimento aos clientes. Abstract in english This article presents a simulation-optimization model application for a real case study in the rolling mill roll sector of a steel plant. The purpose of this study was to get a better area/equipment bottleneck management in the production line. The simulation was used together with an ILP (Integer L [...] inear Programming) optimization model, in order to improve customer service in a made-to-order production. As a result of this ILP and Simulation combined approach, the productive process was optimized and both queues and lead-time were reduced, improving customer service.

Laerte José, Fernandes; Luis Alberto Osés, Rodriguez; Anderson Ribeiro, Correia; Fernando Augusto Silva, Marins.

2013-03-01

52

Rolling friction and bistability of rolling motion  

CERN Document Server

The rolling motion of a rigid cylinder on an inclined flat viscous surface is investigated and the nonlinear resistance force against rolling, $F_R(v)$, is derived. For small velocities $F_R(v)$ increases with velocity due to increasing deformation rate of the surface material. For larger velocity it decreases with velocity due to decreasing contact area between the rolling cylinder and the deformed surface. The cylinder is, moreover, subjected to a viscous drag force and stochastic fluctuations due to a surrounding medium (air). For this system, in a wide range of parameters we observe bistability of the rolling motion. Depending on the material parameters, increasing the noise level may lead to increasing or decreasing average velocity.

Pöschel, T; Brilliantov, N; Zaikin, A; Poeschel, Thorsten; Schwager, Thomas; Brilliantov, Nikolai; Zaikin, Alexei

2005-01-01

53

Analysis of the technology of rolling 5,5 mm-diameter wire rod of cold upsetting steel in the morgan block mill  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The commercial technology of rolling 5,5 mm-diameter wire rod in Poland’s most modern rolling line has been examined within the study. The material used for the investigation was the 20MnB4 steel intended for subsequent cold working. From the performed analysis of the investigation results it has been found that the technology of rolling wire rod of cold upsetting steel, which is used currently in the Rolling Mill under examination, allows the production of finished products that can be def...

Laber, K.; Dyja, H.; Ka?amorz, M.

2015-01-01

54

Rheology of coal-water slurries prepared by the high-pressure roll mill grinding of coal. Final report  

Energy Technology Data Exchange (ETDEWEB)

The preparation of coal water slurries to replace fuel oil for direct combustion has become an important field in modem coal technology. The U.S. Department of Energy has planned or has underway several demonstration projects to burn coal-water slurries to replace fuel oil is attractive not only because there is an assured domestic supply of coal, but also on various technoeconomic grounds. Coal-water slurries combine the handling flexibility of fuel oil in power plants and various other industrial applications. This report discusses the rheology of coal-water slurries and the correlation to the coal preparation by grinding with a choke-fed high pressure roll mill. Performance of the roll mills and energy consumption are described.

Fuerstenau, D.W.; De, A.

1996-08-01

55

Numerical simulation in roll pass design for bar rolling  

Directory of Open Access Journals (Sweden)

Full Text Available The application of finite element simulation to the problem of roll pass design for round bar rolling is considered. Two roll pass sequences were developed by analytical methods and then optimized using 2.5D Finite Element Method (FEM. The first one is a classical oval-round roll pass design. The second one is a combination of flat rolls and round roll passes. Relying on the simulation data obtained by FEM, the roll gaps were adjusted to achieve the required bar shape and the uniform distribution of rolling force between the passes. Advantages and disadvantages of each roll pass design were considered.

S. A. Aksenov

2015-01-01

56

Texture of yttrium rolling  

International Nuclear Information System (INIS)

Textures appearing in yttrium after rolling are studied. It is shown that the yttrium rolling textures are characterized by the prevailing location of basic planes in a parallel to the sheet plane. The increase of deformation degree and yttrium rolling temperature is accompanied by the increase of the sheet basic texture. The deformation and texture formation during yttrium rolling occur at the expense of slip concurrence in two main systems (prismatic and basic). The value of contribution of one or the other system depends on the deformation temperature, which is conditioned by the change of the ratio between critical shift stresses tausub(1010) and tausub(0001)

57

Transverse Crack Modeling of Continuously Casted Slabs through Finite Element Method in Roughing Rolling at Wide Strip Mill  

Science.gov (United States)

In the pipe billet production at the wide strip mills of hot rolling big metal losses are caused by surface defects that affect most parts of the finished strips. The rolling surface defects are referred to the breach of steelmaking technology. Specialists mostly face defects of metal surface such as "scab" and "crack". The only area suffered from these defects is a slab edge. This area has the least surface temperature at the unbending of the continuous-casting machine, and together with deep buckles made by reciprocating motion of the crystallizer it is mostly subjected to transverse cracks that can be up to several millimeters. Each surface defect of the continuously casted slab will further turn into the surface defect of the strip bar. For some grade sets, mostly made of pipe steel grades the amount of strips with these defects can reach up to 60-70%. The area that is mostly prone to these defects is the edge of the strip. The work reveals investigation of the form change peculiarities in the transverse cracks of the continuously casted slab in roughing rolling in the horizontal rollers. The finite element method with software DEFORM 3D V6.1 has been applied in modeling. The work gives a form change mechanism of transverse cracks of slabs in deformation. Further crack growth in rolling is assessed due to Cockroft-Latham criteria.

Pesin, A.; Salganik, V.; Pustovoytov, D.

2010-06-01

58

Improving Thermal Efficiency Of Push Type Furnace In A Hot Re-Rolling Steel Mill By Direct Method : Case Study  

Directory of Open Access Journals (Sweden)

Full Text Available Rolling is the process of reducing the thickness or changing the cross-section of a long work-piece by compressive forces applied through a set of rolls. Rolling accounts for about 90% of all metals produced by metalworking processes. The purpose of Rolling is to convert larger sections into smaller sections, which can be used directly in as rolled state or as stock for working through other processes. As a result of rolling, the coarse structure of cast ingot is converted into a fine grained structure

Jeetendra Mohan Khare

2013-04-01

59

Parametric Roll Instability of Ships  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Parametric roll may be defined as the spontaneous rolling motion of the ship moving in head or following seas that comes about as a result of the dynamic instability of motion. The development of the parametric roll occurs under the conditions that the encounter angular frequency is approximately twice the roll angular frequency, the wavelength is equal to the ship length and the roll damping is insufficient to dissipate the parametric roll energy. In this Thesis t...

Sheikh, Irfan Ahmad

2008-01-01

60

Prediction of work-roll temperature distribution in continuous hot strip rolling process  

Energy Technology Data Exchange (ETDEWEB)

Prediction of temperature distribution within the work-rolls during the hot slab rolling process is of great importance to mill designers. This is because, not only the temperature distribution in rolling material and the dimensional accuracy are depended on work-roll temperature but also the roll life is a function of its temperature distribution. In this paper using the heat transfer equations for moving media and a two dimensional finite element method, the work-roll temperature distribution during continuous hot strip rolling process is predicted. To achieve an accurate temperature field the effects of various factors including the rolling speed, interface heat transfer coefficient, and the amount of slab thickness reduction at each deformation pass are taken into account. Comparison between the predicted and experimental published results depicts the validity of the mathematical model. (author)

Karimi Taheri, A.; Serajzadeh, S. [Sharif University of Technology, Dept. of Material Science and Engineering, Tehran (Iran, Islamic Republic of); Shahriari, M.A.; Izadi, J.; Fattahi, M. [Mobarake Steel Complex, Isfehan (Iran, Islamic Republic of)

2000-07-01

 
 
 
 
61

Prediction of work-roll temperature distribution in continuous hot strip rolling process  

International Nuclear Information System (INIS)

Prediction of temperature distribution within the work-rolls during the hot slab rolling process is of great importance to mill designers. This is because, not only the temperature distribution in rolling material and the dimensional accuracy are depended on work-roll temperature but also the roll life is a function of its temperature distribution. In this paper using the heat transfer equations for moving media and a two dimensional finite element method, the work-roll temperature distribution during continuous hot strip rolling process is predicted. To achieve an accurate temperature field the effects of various factors including the rolling speed, interface heat transfer coefficient, and the amount of slab thickness reduction at each deformation pass are taken into account. Comparison between the predicted and experimental published results depicts the validity of the mathematical model. (author)

62

Prevention of rolled-in defects in cold-rolled ultra-low carbon steels  

International Nuclear Information System (INIS)

The cause of the surface defect in the cold-rolled ultra-low carbon steel was investigated through the analyses of the chemical composition and the size of the defect itself and of the correlation between the defect and the surface deterioration of the finishing work roll in the hot strip mill. It was found that the surface defect was originated from the surface peeling of the fourth finishing work roll, which was related to the severe thermal fatigue damage due to higher hot-rolling temperature. The amount of the defective strips was considerably decreased by intermediate change of the fourth work roll and by increasing the roll coolant and the lubricant. The defect was also decreased by reducing the number of the ultra-low carbon steel coils in one rolling campaign. Complete prevention was achieved by changing the roll material from nickel-grain cast iron to high-chromium cast iron with the superior thermal fatigue property

63

Prevention of rolled-in defects in cold-rolled ultra-low carbon steels  

Energy Technology Data Exchange (ETDEWEB)

The cause of the surface defect in the cold-rolled ultra-low carbon steel was investigated through the analyses of the chemical composition and the size of the defect itself and of the correlation between the defect and the surface deterioration of the finishing work roll in the hot strip mill. It was found that the surface defect was originated from the surface peeling of the fourth finishing work roll, which was related to the severe thermal fatigue damage due to higher hot-rolling temperature. The amount of the defective strips was considerably decreased by intermediate change of the fourth work roll and by increasing the roll coolant and the lubricant. The defect was also decreased by reducing the number of the ultra-low carbon steel coils in one rolling campaign. Complete prevention was achieved by changing the roll material from nickel-grain cast iron to high-chromium cast iron with the superior thermal fatigue property.

Ryu, Jae Hwa; Ryu, Han Bin [Pohang Iron and Steel Co., Ltd., Pohang (Korea, Republic of)

1998-04-01

64

Energy consumption reduction in Ring Rolling processes: a FEM analysis  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Ring Rolling is a very high energy consuming hot forming process used for the production of shaped ring, seamless and axis symmetrical workpieces. Different production steps (Upsetting, Piercing, Ring Rolling) are involved in generating the desired ring shape. In particular the Upsetting and Piercing steps generate a hollow circular preform that will be subsequently enlarged by the rolling mills (Driver, Idle and Axial Rolls) during the Ring Rolling step. In order to reduce the energy and the...

Giorleo, Luca; Ceretti, Elisabetta; Giardini, Claudio

2013-01-01

65

7.SP Rolling Dice  

Science.gov (United States)

This is a task from the Illustrative Mathematics website that is one part of a complete illustration of the standard to which it is aligned. Each task has at least one solution and some commentary that addresses important asects of the task and its potential use. Here are the first few lines of the commentary for this task: Roll two dice 10 times. After each roll, note whether any sixes were observed and record your results in the table below. RollAny Sixes?(Y/N) 1 2 3 4 5...

66

Quantum dice rolling  

Digital Repository Infrastructure Vision for European Research (DRIVER)

A coin is just a two sided dice. Recently, Mochon proved that quantum weak coin flipping with an arbitrarily small bias is possible. However, the use of quantum resources to allow N remote distrustful parties to roll an N-sided dice has yet to be addressed. In this paper we show that contrary to the classical case, N-sided dice rolling with arbitrarily small bias is possible for any N. In addition, we present a six-round three-sided dice rolling protocol, achieving a bias of...

Aharon, N.; Silman, J.

2009-01-01

67

Nanostructured MgH2 obtained by cold rolling combined with short-time high-energy ball milling  

Digital Repository Infrastructure Vision for European Research (DRIVER)

MgH2 was processed by short time high-energy ball milling (BM) and cold rolling (CR). A new alternative processing route (CR + BM) using the combination of CR followed by short time BM step was also applied. The effects on the final morphology, crystalline structure and H-sorption properties were evaluated. The CR + BM processing (compared to BM and CR process) resulted in an inhomogeneous particle size distribution and the biggest crystallite size of MgH2, showing that there is a clear depen...

Ricardo Floriano; Daniel Rodrigo Leiva; Stefano Deledda; Bjørn Christian Hauback; Walter José Botta

2013-01-01

68

Nanostructured MgH2 obtained by cold rolling combined with short-time high-energy ball milling  

Digital Repository Infrastructure Vision for European Research (DRIVER)

MgH2 was processed by short time high-energy ball milling (BM) and cold rolling (CR). A new alternative processing route (CR + BM) using the combination of CR followed by short time BM step was also applied. The effects on the final morphology, crystalline structure and H-sorption properties were evaluated. The CR + BM processing (compared to BM and CR process) resulted in an inhomogeneous particle size distribution and the biggest crystallite size of MgH2, showing that there is a clear depen...

Ricardo Floriano; Daniel Rodrigo Leiva; Stefano Deledda; Bjørn Christian Hauback; Walter José Botta

2012-01-01

69

Spray Rolling Aluminum Strip for Transportation Applications  

Energy Technology Data Exchange (ETDEWEB)

Spray rolling is a novel strip casting technology in which molten aluminum alloy is atomized and deposited into the roll gap of mill rolls to produce aluminum strip. A combined experimental/modeling approach has been followed in developing this technology with active participation from industry. The feasibility of this technology has been demonstrated at the laboratory scale and it is currently being scaled-up. This paper provides an overview of the process and compares the microstructure and properties of spray-rolled 2124 aluminum alloy with commercial ingot-processed material

Kevin M. McHugh; Y. Lin; Y. Zhou; E. J. Lavernia; J.-P. Delplanque; S. B. Johnson

2005-02-01

70

Ship Roll Motion Control  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The technical feasibility of roll motion control devices has been amply demonstrated for over 100 years. Performance, however, can still fall short of expectations because of deciencies in control system designs, which have proven to be far from trivial due to fundamental performance limitations. This tutorial paper presents an account of the development of various ship roll motion control systems and the challenges associated with their design. The paper discusses how to assess performanc...

Perez, Tristan; Blanke, Mogens

2010-01-01

71

Spray Rolling Aluminum Strip  

Energy Technology Data Exchange (ETDEWEB)

Spray forming is a competitive low-cost alternative to ingot metallurgy for manufacturing ferrous and non-ferrous alloy shapes. It produces materials with a reduced number of processing steps, while maintaining materials properties, with the possibility of near-net-shape manufacturing. However, there are several hurdles to large-scale commercial adoption of spray forming: 1) ensuring strip is consistently flat, 2) eliminating porosity, particularly at the deposit/substrate interface, and 3) improving material yield. Through this program, a new strip/sheet casting process, termed spray rolling, has been developed, which is an innovative manufacturing technique to produce aluminum net-shape products. Spray rolling combines the benefits of twin-roll casting and conventional spray forming, showing a promising potential to overcome the above hurdles associated with spray forming. Spray rolling requires less energy and generates less scrap than conventional processes and, consequently, enables the development of materials with lower environmental impacts in both processing and final products. Spray Rolling was developed as a collaborative project between the University of California-Davis, the Colorado School of Mines, the Idaho National Engineering and Environmental Laboratory, and an industry team. The following objectives of this project were achieved: (1) Demonstration of the feasibility of the spray rolling process at the bench-scale level and evaluation of the materials properties of spray rolled aluminum strip alloys; and (2) Demonstration of 2X scalability of the process and documentation of technical hurdles to further scale up and initiate technology transfer to industry for eventual commercialization of the process.

Lavernia, E.J.; Delplanque, J-P; McHugh, K.M.

2006-05-10

72

Ship Roll Damping Control  

DEFF Research Database (Denmark)

The technical feasibility of roll motion control devices has been amply demonstrated for over 100 years. Performance, however, can still fall short of expectations because of difficulties associated with control system designs, which have proven to be far from trivial due to fundamental performance limitations and large variations of the spectral characteristics of wave-induced roll motion. This tutorial paper presents an account of the development of various ship roll motion control systems together with the challenges associated with their design. It discusses the assessment of performance and the applicability of different mathematical models, and it surveys the control methods that have been implemented and validated with full scale experiments. The paper also presents an outlook on what are believed to be potential areas of research within this topic.

Perez, Tristan; Blanke, Mogens

2012-01-01

73

Offensive Rolling in Sambo  

Directory of Open Access Journals (Sweden)

Full Text Available In recent years the Soviet born martial art of sambo has become increasingly well known in martial art circles. This is largely due to the success of sambo fighters in various mixed martial art venues. Offered here is a brief description of sambo’s development as well as a delineation of one of sambo’s hallmark strategies: offensive rolling. Examples of proper forward rolling and three related offensive techniques are presented. This paper provides a brief introduction to sambo’s history and one of its key tactical philosophies.

Stephen Koepfer

2012-07-01

74

Ship Roll Motion Control  

DEFF Research Database (Denmark)

The technical feasibility of roll motion control devices has been amply demonstrated for over 100 years. Performance, however, can still fall short of expectations because of deciencies in control system designs, which have proven to be far from trivial due to fundamental performance limitations. This tutorial paper presents an account of the development of various ship roll motion control systems and the challenges associated with their design. The paper discusses how to assess performance, the applicability of dierent models, and control methods that have been applied in the past.

Perez, Tristan University of Newcastle

2010-01-01

75

Nanostructured MgH2 obtained by cold rolling combined with short-time high-energy ball milling  

Directory of Open Access Journals (Sweden)

Full Text Available MgH2 was processed by short time high-energy ball milling (BM and cold rolling (CR. A new alternative processing route (CR + BM using the combination of CR followed by short time BM step was also applied. The effects on the final morphology, crystalline structure and H-sorption properties were evaluated. The CR + BM processing (compared to BM and CR process resulted in an inhomogeneous particle size distribution and the biggest crystallite size of MgH2, showing that there is a clear dependence between the size/shape of the particles which compose the starting material and the efficiency of crystallite size reduction during the BM process. On the other hand, we observed that a short BM step improved the kinetic properties of the cold rolled material. It shows that the particle size reduction of MgH2 obtained by CR combined with the increase in specific surface area attained by short BM step could be key factors to allow the use of the CR + BM route.

Ricardo Floriano

2012-01-01

76

Nanostructured MgH2 obtained by cold rolling combined with short-time high-energy ball milling  

Directory of Open Access Journals (Sweden)

Full Text Available MgH2 was processed by short time high-energy ball milling (BM and cold rolling (CR. A new alternative processing route (CR + BM using the combination of CR followed by short time BM step was also applied. The effects on the final morphology, crystalline structure and H-sorption properties were evaluated. The CR + BM processing (compared to BM and CR process resulted in an inhomogeneous particle size distribution and the biggest crystallite size of MgH2, showing that there is a clear dependence between the size/shape of the particles which compose the starting material and the efficiency of crystallite size reduction during the BM process. On the other hand, we observed that a short BM step improved the kinetic properties of the cold rolled material. It shows that the particle size reduction of MgH2 obtained by CR combined with the increase in specific surface area attained by short BM step could be key factors to allow the use of the CR + BM route.

Ricardo Floriano

2013-02-01

77

Factors Affecting the Development of Oxide Scales on Austenitic Stainless Steels during Hot Rolling in Steckel Mills  

Science.gov (United States)

The hot rolling of austenitic stainless steels in Steckel Mills introduces particular characteristics to the development of oxides scales and surface structures. In this work, the formation of oxide structures during multipass hot rolling of 302 steel was studied under different sets of processing parameters in a laboratory system designed for the simulation of the Steckel process. The resulting surface structures were characterized by a set of complementary techniques involving scanning electron microscopy, energy-dispersive spectroscopy (EDS), X-ray diffraction (XRD), and glow discharge optical spectroscopy (GDOS). The surface analysis revealed two alternative surface structures: one consisting in a thin protective oxide layer rich in Cr2O3 and the other consisting in thick complex structures containing several successive nonprotective oxide scale and metal layers resulting from a cyclic oxidation pattern involving stages of protective oxidation, chemical breakaway, and duplex oxidation. The critical condition that determined the activation of one mechanism or the other was identified associated with the parabolic rate constant for Cr2O3 growth and the diffusivity of Cr in the alloy. The effects of changes in temperature, deformation, and furnace atmosphere are discussed. Alternatives for controlling scale development are presented.

Cobo, S. J.; Rainforth, W. M.

2008-10-01

78

Nanostructured MgH2 obtained by cold rolling combined with short-time high-energy ball milling  

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: English Abstract in english MgH2 was processed by short time high-energy ball milling (BM) and cold rolling (CR). A new alternative processing route (CR + BM) using the combination of CR followed by short time BM step was also applied. The effects on the final morphology, crystalline structure and H-sorption properties were ev [...] aluated. The CR + BM processing (compared to BM and CR process) resulted in an inhomogeneous particle size distribution and the biggest crystallite size of MgH2, showing that there is a clear dependence between the size/shape of the particles which compose the starting material and the efficiency of crystallite size reduction during the BM process. On the other hand, we observed that a short BM step improved the kinetic properties of the cold rolled material. It shows that the particle size reduction of MgH2 obtained by CR combined with the increase in specific surface area attained by short BM step could be key factors to allow the use of the CR + BM route.

Ricardo, Floriano; Daniel Rodrigo, Leiva; Stefano, Deledda; Bjørn Christian, Hauback; Walter José, Botta.

2013-02-01

79

Slitting criterion for various rolling speeds in MSR rolling process  

Directory of Open Access Journals (Sweden)

Full Text Available Purpose: The main idea of MSR technology is the capability of producing two, three, four and even five rods simultaneously from a single strip in a hot rolling process. Correctly separation of the joined strips is the one of the mainly problem in MSR process. Changing the rolling speed may causes easier of the strand division. In this paper results of the computer simulation of the double slitting rolling process were presented.Design/methodology/approach: For numerical modelling of the multi rolling process a computer program Forge 2005, based by the finished element method was used. As a slitting criterion normalised Cockroft – Latham criterion was used.Findings: For the analysis performed in this study, it was found that increasing of the rolling speed causes of increasing the normalized Cockroft – Latham criterion. For the small values of rolling velocity the strip separation was easier.Research limitations/implications: Multi Slit Rolling process is applied in ribbed rods rolling. Adjusting of the rolling speed in multi slit rolling process could improve of the slitting band to the separated strips.Originality/value: Incorrect construction or bad gap matching could cause lack of separation propelled slitting rolls. The separation of the band is effected by means of separating rollers, which shape must be properly designed to suit to the slitting pass. Changing of the rolling speed could improve of the separation to the single strips.

A. Stefanik

2008-03-01

80

Effect of plate asymmetric rolling parameters on the change of the total unit pressure of roll  

Directory of Open Access Journals (Sweden)

Full Text Available This work shows the results of theoretical analysis of asymmetric rolling process of plates in the finishing mill of plate rolling. Its aim was to determine the influence of asymmetry velocity of working rolls on decrease of unit pressure of metal on the rolls. The lower value of the unit pressure will reduce the elastic deflection of the finishing stand and improve the cross-section shape of plate. Three-dimensional simulation of asymmetric hot rolling of S355J2G3 steel plates was done with the aid of FORGE 2008® software. The tensor polynomial interpolation was used for comparing the values of the unit pressure obtaining from symmetric and asymmetric rolling.

A. Kawalek

2011-07-01

 
 
 
 
81

GRCop-84 Rolling Parameter Study  

Science.gov (United States)

This report is a section of the final report on the GRCop-84 task of the Constellation Program and incorporates the results obtained between October 2000 and September 2005, when the program ended. NASA Glenn Research Center (GRC) has developed a new copper alloy, GRCop-84 (Cu-8 at.% Cr-4 at.% Nb), for rocket engine main combustion chamber components that will improve rocket engine life and performance. This work examines the sensitivity of GRCop-84 mechanical properties to rolling parameters as a means to better define rolling parameters for commercial warm rolling. Experiment variables studied were total reduction, rolling temperature, rolling speed, and post rolling annealing heat treatment. The responses were tensile properties measured at 23 and 500 C, hardness, and creep at three stress-temperature combinations. Understanding these relationships will better define boundaries for a robust commercial warm rolling process. The four processing parameters were varied within limits consistent with typical commercial production processes. Testing revealed that the rolling-related variables selected have a minimal influence on tensile, hardness, and creep properties over the range of values tested. Annealing had the expected result of lowering room temperature hardness and strength while increasing room temperature elongations with 600 C (1112 F) having the most effect. These results indicate that the process conditions to warm roll plate and sheet for these variables can range over wide levels without negatively impacting mechanical properties. Incorporating broader process ranges in future rolling campaigns should lower commercial rolling costs through increased productivity.

Loewenthal, William S.; Ellis, David L.

2008-01-01

82

Rheology of coal-water slurries prepared by the HP roll mill grinding of coal. Quarterly technical progress report No. 6, December 1, 1993--February 28, 1994  

Energy Technology Data Exchange (ETDEWEB)

The effect of the addition of nonionic surfactants on the aggregative stability of coal-water slurries was investigated through determination of sedimentation volumes and floc size distributions. Sedimentation volume measurements for nonionic surfactants show that for Triton X-165, Triton X-305 and Triton X-405, the sedimentation volume decreases slightly with added reagent up to 0.5 wt % addition, decreasing sharply for reagent additions between 0.5 to 0.75 wt %. However, at higher additions, the sedimentation volume levels off for Triton X-165, but increases for both Triton X-305 and Triton X-405. These results are in agreement with the viscosity measurements. Because of its plastic nature, bituminous coal is readily briquetted or agglomerated by the intense localized stresses encountered during comminution in the high-pressure roll mill. The degree of briquetting depends on the nature of the coal and the compressive stresses. We have found that the briquettes can readily be deagglomerated by stirring the comminuted products in a in methanol suspension. Our results show that the amount of minus 200-mesh coal produced depends mainly on the energy invested in the high-pressure roll grinding. The percentage of fines generated increases more or less linearly with the specific grinding energy consumed in the initial stages and tends to level off at the high energy inputs higher than 3 kwh/t. Even at 3.74 kWh/t of energy input, the ground product contained only 30 percent of minus 200-mesh particles, which is much lower than 80 percent of minus 200-mesh particles required in the coalwater slurries for direct combustion in power plants. Therefore, future work will encompass grinding of the high-pressure roll milled product in ball mill or rod mill, using hygrid HP roll mill/ball mill circuit for feed preparation.

Fuerstenau, D.W.

1994-03-01

83

Walk and roll robot  

Science.gov (United States)

A mobile robotic unit features a main body, a plurality of legs for supporting the main body on and moving the main body in forward and reverse directions about a base surface, and a drive assembly. According to an exemplary embodiment each leg includes a respective pivotal hip joint, a pivotal knee joint, and a wheeled foot adapted to roll along the base surface. Also according to an exemplary embodiments the drive assembly includes a motor operatively associated with the hip and knee joints and the wheeled foot for independently driving pivotal movement of the hip joint and the knee joint and rolling motion of the wheeled foot. The hip joint may include a ball-and-socket-type joint interconnecting top portion of the leg to the main body, such that the hip joint is adapted to pivot said leg in a direction transverse to a forward-and-reverse direction.

Wilson, Andrew (Inventor); Punnoose, Andrew (Inventor); Strausser, Katherine (Inventor); Parikh, Neil (Inventor)

2011-01-01

84

Modernitetens Rolle Under Holocaust  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Abstract Projektet søger, ved hjælp af Zygmunt Baumans modernitetsteori, at afklare hvilken rolle moderniteten spillede i tilblivelsen af Holocaust. Propagandaen var en markant del af det nazistiske bureaukratiske styre, men da Bauman ikke udførligt diskuterer dette, er det et emne, vi ønsker at belyse nærmere. Dette gøres ved at analysere de to nazistiske propagandafilm, Der Ewige Jude og Jud Süss. Moderniteten indeholder faktorer, som kan være behjælpelige til en forståelse af,...

Jespersen, Simon M.

2012-01-01

85

Speed roll laws influence in a Ring Rolling process  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Ring Rolling is a complex hot forming process used for the production of shaped rings, seamless and axis symmetrical workpieces. The main advantage of workpieces produced by ring rolling, compared to other technological processes, is given by the size and orientation of grains, especially on the worked surface which give to the final product excellent mechanical properties. In this process different rolls (Idle, Axial, Guide and Driver) are involved in generating the desired ring shape. Becau...

Giorleo, Luca; Ceretti, Elisabetta; Giardini, Claudio

2013-01-01

86

DEFECTS SIMULATION OF ROLLING STRIP  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The defects in the continuous casting slabs can be developed or kept down in principle by rolling technology, especially depend to sort, size and distribution of primary defects, as well as used of rolling parameters. Scope of the article is on observation behavior artificial surface and undersurface defects (scores) without filler (surface defects) and filling by oxides and casting powder (subsurface defects). First phase of hot rolling process have been done by software simulation DEFORM 3D...

Rudolf Miši?ko; Tibor Kva?kaj; Martin Vlado; Lucia Gulová; Miloslav Lupták; Jana Bidulská

2009-01-01

87

G-MG Toilet Roll  

Science.gov (United States)

This is a task from the Illustrative Mathematics website that is one part of a complete illustration of the standard to which it is aligned. Each task has at least one solution and some commentary that addresses important asects of the task and its potential use. Here are the first few lines of the commentary for this task: Picture a roll of toilet paper; assume that the paper in the roll is very tightly rolled. Assuming that the paper in the roll is very thin, find a rela...

88

Effect of the microstructure on tribological phenomena occurring on the surface of a mill roll made of SA5T cast iron (GJSL-HV600 - GJSL-330NiMoCr12-8-3  

Directory of Open Access Journals (Sweden)

Full Text Available This paper deals with the role of the microstructure in the tribological wear processes occurring in a cast iron mill roll. For this purpose, a piece of a broken roll, made in Italy, was collected. Its microstructure consisted of modular graphite, transformed ledeburite and a matrix composed of bainite and martensite. Metallographic investigations were performed on the roll working surface in conjunction with metallographic tests effected within its surface layer. There was established the relation between the microstructure of the roll and the process of its tribological wear. The following was ascertained: micro-shrinkages or graphite precipitations nearby the working area cause cracks between those places and the working area; in the surface layer, cracks occur usually in the zone of ledeburitic cementite. At places of considerable precipitations of ledeburitic cementite, the tribological wear intensity of the roll is lower. A banded layout of precipitations of ledeburitic cementite facilitates a selective spalling of some parts of the roll material. The results of this study allow broadening the data base related to the effect of the microstructure on tribological wear of mill rolls, which in future will permit one to design their proper microstructure of cast iron mill rolls.

J. Krawczyk

2008-07-01

89

Rolling cuff flexible bellows  

Science.gov (United States)

A flexible connector apparatus used to join two stiff non-deformable members, such as piping. The apparatus is provided with one or more flexible sections or assemblies each utilizing a bellows of a rolling cuff type connected between two ridge members, with the bellows being supported by a back-up ring, such that only the curved end sections of the bellows are unsupported. Thus, the bellows can be considered as being of a tube-shaped configuration and thus have high pressure resistance. The components of the flexible apparatus are sealed or welded one to another such that it is fluid tight.

Lambert, Donald R. (Livermore, CA)

1985-01-01

90

STS-49 Roll Out  

Science.gov (United States)

One step closer to its maiden voyage, the Space Shuttle Orbiter Endeavour rolls out of the Vehicle Assembly Building, headed to Launch Pad 39B. Launched on May 7th 1992, the STS-49 mission was the first U.S. orbital flight to feature 4 extravehicular activities (EVAs), and the first flight to involve 3 crew members working simultaneously outside of the spacecraft. The primary objective was the capture and redeployment of the INTELSAT VI (F-3) which was stranded in an unusable orbit since its launch aboard the Titan rocket in March 1990.

1992-01-01

91

Textures of molybdenum monocrystal deformation in rolling in profiled rolls  

International Nuclear Information System (INIS)

The texture of molybdenum monocrystals rolled in profiled rolls with epsilon=6-90% cogging is studied by the method of reverse pole figures in Mo Ksub(?) radiation. The crystallographic directions of and were oriented in the deformation direction. At different orientation of the monocrystal in the rolling plane after epsilon=25-27% in the rolling direction (RD) different crystallographic orientations were formed which is caused by pointing accuracy of the monocrystal in the deformation plane. Rolling of a monocrystal with long RD orientation provokes RD reorientation and formation of the (111) [011] texture at high deformation degree. At average cogging degrees (epsilon=35-60%) the total axial texture long RD is formed transforming into a limited axial one and then into an axial one with the deformation degree increase

92

Rolling friction of adhesive microspheres  

Science.gov (United States)

The rolling friction of adhesive microspheres is an important quantity as it determines the strength and stability of larger aggregates. Current models predict rolling forces that are 1 to 2 orders of magnitude smaller than observed experimentally. Starting from the well-known Johnson-Kendall-Roberts (JKR) contact description, we derive an analytical theory for the rolling friction based on the concept of adhesion hysteresis, e.g. a difference in apparent surface energies for opening/closing cracks. We show how adhesion hysteresis causes the pressure distribution within the contact to become asymmetrical, leading to an opposing torque. Analytical expressions are derived relating the size of the hysteresis, the rolling torque, and the rolling displacement, ?. We confirm the existence of a critical rolling displacement for the onset of rolling, the size of which is set by the amount of adhesion hysteresis and the size of the contact area. We demonstrate how the developed theory is able to explain the large rolling forces and particle-size dependence observed experimentally. Good agreement with experimental results is achieved for adhesion hysteresis values of (??/?) ? 3 for polystyrene, and (??/?) ? 0.5 for silicates, at crack propagation rates of 0.1 µm s-1 and 1-10 µm s-1, respectively.

Krijt, S.; Dominik, C.; Tielens, A. G. G. M.

2014-04-01

93

Slipping and Rolling Wheel Model  

Science.gov (United States)

The EJS Slipping and Rolling Wheel Model shows the motion of a wheel rolling on a floor subject to friction. The simulation allows the user to change the initial translational and rotational velocities of the wheel, v and ?, the mass, radius, and mass distribution, R, m, and C of the wheel. By controlling these variables, the dynamics of the wheel can be changed to show the sliding, then rolling without slipping, of the wheel. The Slipping and Rolling Wheel Model was created using the Easy Java Simulations (EJS) modeling tool. It is distributed as a ready-to-run (compiled) Java archive. Double clicking the ejs_mech_newton_SlippingRollingWheel.jar file will run the program if Java is installed. The user can modify this simulation if EJS is installed by right-clicking within the plot and selecting âOpen Ejs Modelâ from the pop-up menu item.

Christian, Wolfgang; Belloni, Mario

2009-02-26

94

Rolling Stone Radio  

Science.gov (United States)

Rolling Stone Radio is a fun and interesting site that may represent the future of Internet radio. The site provides a number of streaming audio channels that can be listened to via RealNetworks' RealPlayer G2 combined with a customized, radio-like interface to the site. Each channel features a particular genre of music, and the interface displays the artist and song title during play. The sound quality ranges from acceptable to excellent, and the sound controls and channel selectors are easy-to-use. While the site borders on the exploitative in its advertising and ability to purchase music by clicking through the interface, it does combine some of the best ideas on the Internet into a seamless entertainment package. All downloadable components of this site are free but run only on Win95/98/NT.

95

Using Variable Perturbation Method to Study the Stability of Torsional Self-Excited Vibration in Main Drive System of Rolling Mill  

Directory of Open Access Journals (Sweden)

Full Text Available The self-excited vibration of blooming mill is a kind of torsional vibration, which occurs only when the rolling machine slips under appropriate conditions. Once in place, this may cause the larger peak pressure of each component in the main drive system; reduce the service life of the components, cause components? damage directly. A large number of studies have shown that, at present there are not effective methods for diagnosis, monitoring of slipping and take proper measures in time to stop slipping so as to avoid the occurrence of malignant accidents. In this paper, author set out from another angle, take the main drive system of rolling mill as an example, to study stability of self-excited vibration. The conditions of the stable vibration are gained. By combining with the actual working conditions of blooming mill, author has put forward some effective measures to meet the stable conditions in order to make the blooming mill work in the stable state. Practice research has proved that the effective measures can contribute to reduce structural damage directly caused by the torsional vibration when “slipping” phenomenon occurred and to extend the service life of the components.

Fenglan Wang

2013-06-01

96

Roll Control in Fruit Flies  

CERN Document Server

Due to aerodynamic instabilities, stabilizing flapping flight requires ever-present fast corrective actions. Here we investigate how flies control body roll angle, their most susceptible degree of freedom. We glue a magnet to each fly, apply a short magnetic pulse that rolls it in mid-air, and film the corrective maneuver. Flies correct perturbations of up to $100^{\\circ}$ within $30\\pm7\\mathrm{ms}$ by applying a stroke-amplitude asymmetry that is well described by a linear PI controller. The response latency is $\\sim5\\mathrm{ms}$, making the roll correction reflex one of the fastest in the animal kingdom.

Beatus, Tsevi; Cohen, Itai

2014-01-01

97

Nonlinear Observers for Parametric Roll  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Parametric roll resonance is a dangerous resonance phenomenon affecting several kinds of ships, such as cruise ships, fishing vessels and container ships. In a worst case scenario parametric roll resonance may lead to roll angles of up to 50 degrees, capsizing of the vessel, or damage of goods and ship for tens of millions of dollars, citep{Ginsberg1998}.Accurate equations in the model for the ship motion are important because they are directly related to the observer design. There has been d...

Olsen, Gunnhild Konstanse Hoff

2012-01-01

98

Numerical simulation of shape rolling  

Digital Repository Infrastructure Vision for European Research (DRIVER)

In the first part of this thesis, the FE program MSC.Marc is applied for coupled thermomechanical simulations of wire-rod rolling. In order to predict material behaviour of an AISI 302 stainless steel at high strain rates generated during wire-rod rolling, a material model based on dislocation density is applied. Then, the evolution of temperature, strain rate and flow stress is predicted in the first four rolling passes of a wire block. In the second part of the thesis, an alternative approa...

Riljak, Stanislav

2006-01-01

99

Rolling Resistance Measurement and Model Development  

DEFF Research Database (Denmark)

There is an increased focus worldwide on understanding and modeling rolling resistance because reducing the rolling resistance by just a few percent will lead to substantial energy savings. This paper reviews the state of the art of rolling resistance research, focusing on measuring techniques, surface and texture modeling, contact models, tire models, and macro-modeling of rolling resistance

Andersen, Lasse Grinderslev; Larsen, Jesper

2015-01-01

100

Body roll in swimming: a review.  

Science.gov (United States)

In this article, we present a critical review of the swimming literature on body roll, for the purposes of summarizing and highlighting existing knowledge, identifying the gaps and limitations, and stimulating further research. The main research findings can be summarized as follows: swimmers roll their shoulders significantly more than their hips; swimmers increase hip roll but maintain shoulder roll when fatigued; faster swimmers roll their shoulders less than slower swimmers during a 200-m swim; roll asymmetries, temporal differences in shoulder roll and hip roll, and shoulder roll side dominance exist in front crawl swimming, but there is no evidence to suggest that they affect swimming performance; and buoyancy contributes strongly to generating body roll in front crawl swimming. Based on and stimulated by current knowledge, future research should focus on the following areas: calculation of body roll for female swimmers and for backstroke swimming; differences in body roll between breathing and non-breathing cycles; causes of body roll asymmetries and their relation to motor laterality; body roll analysis across a wide range of velocities and swimming distances; exploration of the association between body roll and the magnitude and direction of propulsive/resistive forces developed during the stroke cycle; and the influence of kicking actions on the generation of body roll. PMID:20131140

Psycharakis, Stelios G; Sanders, Ross H

2010-02-01

 
 
 
 
101

Frontal Impact of Rolling Spheres.  

Science.gov (United States)

A model of the inelastic collision between two spheres rolling along a horizontal track is presented, taking into account the effects of frictional forces at impact. This experiment makes possible direct estimates of the coefficients of restitution and friction. (Author)

Domenech, A.; Casasus, E.

1991-01-01

102

Chirality in Swiss Roll metamaterials  

Energy Technology Data Exchange (ETDEWEB)

A numerical investigation is presented for the electromagnetic behaviour of Swiss Roll metamaterials that show considerable agreement with analytical theory. Their chiral design exhibits enormous chirality, at least 100 times larger than other chiral structures previously reported in the literature. This property ensures the change of a wave polarization by 90{sup 0} in less than a wavelength. Hence, chiral Swiss Rolls support a negative refractive band for one-wave polarization, which is predicted analytically and calculated numerically.

Demetriadou, A., E-mail: ademetri@imperial.ac.u [Blackett Laboratory, Imperial College London, SW7 2AZ (United Kingdom); Pendry, J.B. [Blackett Laboratory, Imperial College London, SW7 2AZ (United Kingdom)

2010-07-15

103

Grease lubrication in rolling bearings  

CERN Document Server

The definitive book on the science of grease lubrication for roller and needle bearings in industrial and vehicle engineering. Grease Lubrication in Rolling Bearings provides an overview of the existing knowledge on the various aspects of grease lubrication (including lubrication systems) and the state of the art models that exist today. The book reviews the physical and chemical aspects of grease lubrication, primarily directed towards lubrication of rolling bearings. The first part of the book covers grease composition, properties and rheology, including thermal

Lugt, Piet M

2012-01-01

104

Fundamentals of Rolling Contact Fatigue:  

Digital Repository Infrastructure Vision for European Research (DRIVER)

In the mechanical industry there is a need for continuous development towards increasing performance of various types of machinery. Critical components in such machines are exposed to gradually harsher operating environments involving higher cyclic stresses and operating temperatures. Examples of such fatigue-exposed components are gears, camshafts and rolling element bearings in engines and gearboxes. The components in the bearing industry are always subject to the high cycle rolling contact...

Grabulov, A.

2010-01-01

105

NORMAL PRESSURE AND FRICTION STRESS MEASUREMENT IN ROLLING PROCESSES  

DEFF Research Database (Denmark)

A load transducer has been developed to measure the contact forces in the deformation zone during rolling. The transducer consists of a strain gauge equipped insert, embedded in the surface of the roll. The length of the insert exceeds the contact length between material and roll. By analyzing the output from the transducer, the friction stress and normal pressure in the contact zone can be determined. The new concept differs from existing pin designs by a lower disturbance of lubricant film and material flow and limited penetration of material between transducer and roll. Aluminum, cupper and steel strips with a width of 40 mm was rolled with reduction varying from 2.7% to 29%, in a pilot mill. For evaluating the transducer, the measured contact forces are compared with external measurements of roll separating forces and torque. The determined friction coefficients are compared with values found by forward slip measurements.

Henningsen, Poul; Arentoft, Mogens

2005-01-01

106

Numerical analysis of cross shear plate rolling  

DEFF Research Database (Denmark)

The rolling process is widely applied for industrial production of metal plates. In conventional plate rolling the two work rolls are rotating at the same peripheral speed. By introducing a specific difference in the speed of the two work rolls, cross shear rolling is introduced forming a central shear zone between the forward and backward slip zones in the deformation zone thus lowering the rolling load. A numerical analysis of the cross shear rolling process is carried out based on the slab method adopting Wanheim and Bay's general friction model. The pressure distribution along the contact are in the roll gap, the position and the size of the shear zone and the rolling load are calculated. Experimental results are presented verifying the calculations. The numerical analysis facilitates a better understanding of the mechanics in cross shear plate rolling.

Zhang, Wenqi; Bay, Niels

1997-01-01

107

Multi-stage FE simulation of hot ring rolling  

Science.gov (United States)

As a unique and important member of the metal forming family, ring rolling provides a cost effective process route to manufacture seamless rings. Applications of ring rolling cover a wide range of products in aerospace, automotive and civil engineering industries [1]. Above the recrystallization temperature of the material, hot ring rolling begins with the upsetting of the billet cut from raw stock. Next a punch pierces the hot upset billet to form a hole through the billet. This billet, referred to as preform, is then rolled by the ring rolling mill. For an accurate simulation of hot ring rolling, it is crucial to include the deformations, stresses and strains from the upsetting and piercing process as initial conditions for the rolling stage. In this work, multi-stage FE simulations of hot ring rolling process were performed by mapping the local deformation state of the workpiece from one step to the next one. The simulations of upsetting and piercing stages were carried out by 2D axisymmetric models using adaptive remeshing and element erosion. The workpiece for the ring rolling stage was subsequently obtained after performing a 2D to 3D mapping. The commercial FE package LS-DYNA was used for the study and user defined subroutines were implemented to complete the control algorithm. The simulation results were analyzed and also compared with those from the single-stage FE model of hot ring rolling.

Wang, C.; Geijselaers, H. J. M.; van den Boogaard, A. H.

2013-05-01

108

Effects of hot-rolling temperature and reduction ratio on edge cracking of hot-rolled boron-stainless steel  

International Nuclear Information System (INIS)

The effects of hot-rolling temperature and reduction ratio on edge cracking in hot-rolled stainless steel containing 1.1% boron were investigated by using a hot-mill simulator. The main results are as follows: (1) The temperature at the side of hot-rolled steel sheets (Ts) during hot-rolling was significantly lower than at the center of hot-rolled steel sheets (Tp) just before hot rolling. (2) Ts at the start of edge cracking was not constant and increased with increasing reduction per pass. (3) The total reduction until the start of edge cracking was constant and was not dependent on Ts or the reduction per pass. (4) It is concluded that total reduction is the main factor in edge cracking due to rapid work hardening of the matrix (?phase), and owing to cavities occurring at the interface of the matrix and boride under constant strain conditions. (author)

109

Studying possibilities to improve the functional properties of metallurgical rolls  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Thc paper prcscnts rcsults nT invcst igations and at~thors' opinion on improving functional propcrtics of mciall urgicnl rolls cast fromGZOOCrMoNi 4-9-3 cast wccl. onc nf most oftcn ilscd lor rolls in scction mills. Thcsc mills Icn~urcq uickcr than flat rolls wear or 1001'spass. whar rcquircs morc Crcqocnt rcpcncr;lt ion. 'Thc machining rcquircs n rclat ivcly low hardness, which is cnsurcd hy ~ h pcc arliiic matrixof casr steel strldid. 7 % ~au thors silggcst 10 achicvc thc optimisntion o f t...

Stradomski, Z.; Pirek, A.; Stachura, S.

2008-01-01

110

Modeling recrystallization kinetics during strip rolling  

Energy Technology Data Exchange (ETDEWEB)

In order to simulate the microstructural evolution during hot strip rolling, double-hit compression tests have been carried out on plain carbon steels. Using the softening data obtained by these tests, mathematical models were developed to predict the overall kinetics of static recrystallization under roughing and finishing mill conditions. These models include the effects of deformation temperature, applied strain, strain rate and initial austenite grain size. Predictions based on these models are in reasonable agreement with the present experimental results.

Sun, W.P.; Hawbolt, E.B.; Meadowcroft, T.R. [Univ. of British Columbia, Vancouver (Canada). The Centre for Metallurgical Process Engineering

1995-01-01

111

Characterization of roll bite heat transfers in hot steel strip rolling and their influence on roll thermal fatigue degradation  

Digital Repository Infrastructure Vision for European Research (DRIVER)

A temperature sensor with a thermocouple placed at ~0.5 mm from roll surface is used in hot rolling conditions to evaluate by inverse calculation heat transfers in the roll bite. Simulation analysis under industrial hot rolling conditions with short contact lengths (e.g. short contact times) and high rolling speeds (7 m./s) show that the temperature sensor + inverse analysis with a high acquisition frequency (> 1000 Hz) is capable to predict accurately (5 to 10% error) the roll bite peak of t...

Legrand, Nicolas; Weisz-patrault, Daniel; Horsky, Jaroslav; Luks, Tomas; Labbe, Nathalie; Picard, Michel; Ehrlacher, Alain

2013-01-01

112

Roll casting of 5182 aluminium alloy  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Purpose: of this paper is investigation of the ability of the high speed roll casting of 5182 aluminium alloy. Appropriate twin roll caster to cast the 5182 strip was researched.Design/methodology/approach: Method used in the present study was an unequal diameter twin roll caster and a vertical type high speed twin roll caster equipped with mild steel rolls without parting material.Findings: are that the vertical type high speed twin roll caster was effective to cast 5182 strip at high speed....

Haga, T.; Mtsuo, M.; Kunigo, D.; Hatanaka, Y.; Nakamuta, R.; Watari, H.; Kumai, S.

2009-01-01

113

Robust Rudder Roll Damping Control  

DEFF Research Database (Denmark)

The results of a systematic research to solve a specific ship motion control problem, simultaneous roll damping and course keeping using the rudder are presented in this thesis. The fundamental knowledge a priori is that rudder roll damping is highly sensitive to the model uncertainty, therefore H-infinity theory is used to deal with the problem. The necessary mathematical tools and the H-Infinity theory as the basis of controller design are presented in Chapter 2 and 3. The mu synthesis and the D-K iteration are introduced in Chapter 3. The ship dynamics and modeling technology are discussed in Chapter 4, two kinds of ship model have been obtained: linear ship model used for designing the controller and nonlinear model used for simulation. The ship model uncertainty is discussed in this chapter and so is a wave model because the ship's roll motion is caused by waves. Using an unstructured model of uncertainty, three controllers with different kind of control schemes are designed by the mixed sensitivity method in Chapter 5. Sea-way simulation results show that each of these controllers have good robust stability and performance. The roll damping reduction is above 35% for all of these controllers. Roll reduction of near 70% has been obtained by the cascade controller. Using structured model of uncertainty, a m controller is designed in Chapter 6. The good robust performance has been recognized in the simulation results. It is shown that the m controller has the best robust characteristics with respect to model uncertainty and the roll reduction is near 50% with an envelope of model perturbations.

Yang, C.

1998-01-01

114

Robust Rudder Roll Damping Control  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The results of a systematic research to solve a specific ship motion control problem, simultaneous roll damping and course keeping using the rudder are presented in this thesis. The fundamental knowledge a priori is that rudder roll damping is highly sensitive to the model uncertainty, therefore H-infinity theory is used to deal with the problem. The necessary mathematical tools and the H-Infinity theory as the basis of controller design are presented in Chapter 2 and 3. The mu synthesis and ...

Yang, C.

2005-01-01

115

Optimisation of cricket pitch rolling  

Digital Repository Infrastructure Vision for European Research (DRIVER)

In the game of cricket, where a ball is bounced on a natural clay soil pitch between the ‘bowler’ and ‘batsman’, the ball-surface interaction is critical and is one of the most important factors responsible for the quality of play. Rolling of the playing surface with a smooth-wheel roller is common practice and this is intended to encourage pace, but with a predictable ball bounce that will provide a fair and safe playing surface. Current rolling management is largely b...

Shipton, Peter

2008-01-01

116

Tallinnas on kõne all spordi muutuv roll kõrghariduses / Raivo Russmann, Malle Jürves  

Index Scriptorium Estoniae

Tallinna Tehnikakõrgkooli korraldusel toimub 8.-12. novembrini Tallinnas 9. üle-euroopalise kõrgkoolide spordikeskuste assotsiatsiooni ENAS konverents, mille teemaks on spordi muutuv roll kõrghariduses

Russmann, Raivo

2006-01-01

117

Energy-force conditions for rolling of titanium alloys in cross-shaped tetraroll calibers  

International Nuclear Information System (INIS)

In case of rolling high-strength titanium alloys VT14, VT9, VT8 the metal pressure upon the rolls is 1.5 - 2 times more than in case of rolling VT5, OT4 alloys of a medium strength and 3-4 times more than in case of rolling VTI-0 technical titanium. The results obtained may be employed for the determination of methods of thin-wall profile rolling as well as for designing mills with multi-roll passes

118

Cell sorting by deterministic cell rolling  

Digital Repository Infrastructure Vision for European Research (DRIVER)

This communication presents the concept of “deterministic cell rolling”, which leverages transient cell-surface molecular interactions that mediate cell rolling to sort cells with high purity and efficiency in a single step.

Choi, Sungyoung; Karp, Jeffrey M.; Karnik, Rohit

2011-01-01

119

14 CFR 25.349 - Rolling conditions.  

Science.gov (United States)

...following conditions, speeds, and aileron deflections...corresponding to steady rolling velocities must be investigated...corresponding to maximum angular acceleration must be investigated...conditions, zero rolling velocity may be assumed in...

2010-01-01

120

Controlling the Roll Responses of PCTC's  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Modern Panamax Pure Car and Truck Carriers (PCTC) have become more vulnerable to critical roll responses as built in margins have been traded against increased transport efficiency. The research presented in this licentiate thesis aims at enhancing the predictability and control of these critical roll responses. The thesis presents the development of a new method for assessing the roll damping, which is a crucial parameter for predicting roll motions. The method involves a unique set up of fu...

So?der, Carl-johan

2013-01-01

 
 
 
 
121

Application research of ferrous matrix composites in roller ring used in high-speed wire/bar rolling mill  

International Nuclear Information System (INIS)

Research highlights: ? A composite structure roller rings was fabricated by centrifugal casting. ? The roller rings consisted of outer WCP/Fe-C composites layer and inner Fe-C alloy matrix. ? Hardness attained to HRA80-85 in the composites layer, and HRA73-76 in inner Fe-C alloy matrix where the toughness was over 8 J/cm2. ? The wear resistance of the roller rings excelled that of high-speed steel, and approached to that of the WC hard alloy roll. ? The production cost of the WCP/Fe-C composites roller ring decreased by 50%. - Abstract: Tungsten carbide particle (WCP) reinforced ferrous matrix composites roller rings were fabricated by centrifugal casting. The microstructures, properties and application effect of the composites roller rings were investigated by SEM, TEM and various property testers. The experimental results show that the WCP were uniformly distributed in outer reinforced-layer (working-layer) of 20-50 mm in thickness and their volume fraction reached 60-80 vol.%; there was a good interface bonding between WCP and Fe-C alloy without any reaction products; hardness attained to HRA80-85 in working-layer, and HRA73-76 in inner ferrous matrix where the toughness was over 8 J/cm2; the wear resistance of the composites roller rings excels that of high-speed steel; service life of the composites parts approached to that of the WC hard alloy roll when the same WCP-volume-fraction in woub>P-volume-fraction in working-layer were obtained for both of them, but the production cost of the WCP/Fe-C composites roller ring decreased by 50%.

122

Improvement in rolling workability of Fe3Al by high-speed rolling  

Science.gov (United States)

High-speed rolling is expected to improve the deformability of difficult-to-work alloys. In this work, high-speed rolling was applied to Fe3Al, and the rolling workability was investigated. Fe-28%Al was prepared by plasma arc melting and multi-pass hot-rolled to a sheet 2 mm in thickness, followed by heat-treatment. Both the hot-rolling and heat-treatment were carried out at 1173 K. These specimens were rolled in a one-pass operation with a thickness reduction of 30 % at 1000 m/min in the temperature range from 573 to 973 K. Rolling at 5 m/min was also conducted for comparison. Sound sheets without defects or cracks were obtained even at 673 K in the high-speed rolling, while sound sheets were obtained only above 1173 K in the low-speed rolling. EBSD analysis showed that fine grains were formed either after the high-speed rolling at 873 K or after the low-speed rolling at 1073 K. Vickers hardness is not sensitive to the rolling speed below 773 K and decreased above 773 K and 1173 K in the high-speed rolling and low-speed rolling, respectively. The rolling workability of Fe3Al was significantly improved by the high-speed rolling.

Muraoka, A.; Utsunomiya, H.; Matsumoto, R.; Sakai, T.

2012-08-01

123

ALE3D Rolling Simulations  

Energy Technology Data Exchange (ETDEWEB)

Hot rolling is a problem involving large deformations during the process of turning an ingot into a thin sheet. As a result of the large deformations inherent in the process, significant amounts of energy are put into the ingot mechanically, most of which results in heat generation. Therefore, in order to predict the results of rolling both the mechanical and the thermal factors must accurately represent the real conditions. The factors which must be properly tuned include interface friction, mass scaling to decrease computation times, heat transfer at the interface, convective heat transfer from the ingot, and convective heat transfer from the roll. Since these parameters are generally not measurable the correct values must be derived by tuning the parameters so that solutions match some other measurable result. The interface friction will be tuned using an ALE3D input deck which has been set up to output the torque applied to the roll during the pass. The friction coefficient will be adjusted so that the computed torque matches the measured value. The various heat transfer coefficients are dependent on each other, and are tuned based on measured roll surface temperatures, ingot exit temperatures, and the energy input through the mechanical deformation of the ingot. The heat transfer coefficient at the interface has been found to be approximately 1.25 x 10{sup 5} W/m{sup 2}K, based on estimates of how much heat can be taken from the roll surface by coolant and matching a roll surface temperature. The convection coefficient on the ingot surface has been assumed to be 100 W/m{sup 2}K, on the high end for convection to air. However, this convection coefficient is low enough that the ingot should cool uniformly through its thickness as it would with a lower convection coefficient. Also necessary in accurate modeling is a good description of material behavior. In order to aid the development of an accurate material model an ALE3D input deck which simulates compression tests with temperature gradients has been developed. The model output engineering stress-strain curves which can be compared to the experimentally collected data. Also, comparisons of the deformed shapes can be made. The model has been tuned using MTS parameters for AA 5182 and will be ready for use when parameters for AA 2024 are experimentally developed. Currently, more work is needed to properly tune all the model parameters. A parameterized three dimensional geometry and mesh has been created so that once the parameters are tuned the transition to three dimensional simulations should be quick.

Riordan, T

2006-07-27

124

A new sensor for the evaluation of contact stress by inverse analysis during steel strip rolling  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Knowledge of the contact stress between roll and strip becomes a critical factor in modern, high-speed rolling mills. In this paper, an inverse analytical method is developed to determine the contact stress in the roll gap by measuring the stress tensor with fibre optics at only one point inside the roll. Unlike many inverse methods, no matrix inversion is needed because the very small contact length would lead to ill-conditioned matrices. Iterative methods are also not studied because short ...

Weisz-patrault, Daniel; Ehrlacher, Alain

2011-01-01

125

9 CFR 381.159 - Poultry rolls.  

Science.gov (United States)

...substances are permitted for use as binders in poultry rolls: transglutaminase enzyme at up to 65 ppm. When binding agents are added in excess...included in the name of the product; e.g., “Turkey Roll-Gelatin Added.” (b) With respect to heat processed rolls,...

2010-01-01

126

Development of dissimilar metal transition joint by hot bond rolling  

International Nuclear Information System (INIS)

Metallurgically bonded transition joints which enable to connect reprocessing equipments made of superior corrosion resistant valve metals (Ti-5Ta, Zr or Ti) to stainless steel piping are required for nuclear fuel reprocessing plants. The authors have developed dissimilar transition joints made of stainless steel and Ti-5Ta, Zr or Ti with an insert metal of Ta by the hot bond rolling process of clad bars and clad pipes, using a newly developed mill called 'rotary reduction mill'. This report presents the manufacturing process of dissimilar transition joints produced from the clad pipe with three layers by the hot bond rolling. First, the method of hot bond rolling of clad pipe is proposed. Then, the mechanical and corrosion properties of the dissimilar transition joints are evaluated in detail by carrying out various tests. Finally, the rolling properties in the clad pipe method are discussed. (author)

127

FEM Analysis of Effect of Rolling Parameters on Cold Rolling Process  

Digital Repository Infrastructure Vision for European Research (DRIVER)

A FEM simulation study was carried out to investigate the influence of the rolling parameters on the rolling process. Using commercial FEM software, ABAQUS, a number of cases were studied. In this paper, a two-dimensional Elastic-plastic finite element model to simulate the cold rolling of thick strip with different roll angular velocity and roll diameter models is described. The angular velocity of the rigid rolls ranged from 30 to 480 revolutions per minute (r.p.m.) and the rigid roll diame...

Devarajan, K.

2012-01-01

128

Kommunikatsiooni roll kiirelt muutuvas maailmas / Susan Lilleväli, Marit Priks  

Index Scriptorium Estoniae

Tartu Ülikooli akadeemilise kommunikatsiooni klubi kolmandast kohtumisest, mille teemaks oli "Kuidas hallata komplekssust?". Tartu Ülikooli doktorant Regina Salmu tutvustas oma uurimistööd, mille keskmes on innovaatiliste teenuste arendusprotsessid ning kommunikatsiooni roll selles. Teises töörühmas arutati erinevatest kanalitest sissetuleva info kvaliteedi ja publitseeritavuse üle otsustamisest ajakirjandusväljaannete toimetuste töös

Lilleväli, Susan

2014-01-01

129

The formation of edge cracks during rolling of metal sheet  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Many metals tend to develop edge cracks during hot and cold rolling. Edge cracks need to be removed by a trimming operation, and they may cause rupture of the sheet in the rolling mill. Hence, there is a strong motivation to understand the mechanisms of edge crack formation and to develop predictive tools for controlling the phenomenon. The present work explores the applicability of damage mechanics models to this problem. In conjunction with a plausible failure criterion the Gologanu-Leblond...

Riede, H.; Andrieux, F.; Walde, T.; Karhausen, K. -f

2007-01-01

130

Improving energy efficiency of reheating furnace of sheet ingot plant and rolling mill Calibers of Gecamines / Lubumbashi by the recovery of waste heat of smoke  

International Nuclear Information System (INIS)

The economic management of energy is an important topic in industrial processes to the extent that it ensures the competitiveness of any firm and ensures its survival. Within this framework we plan to improve the energy efficiency of the powerful furnace for reheating lingots Rolling Mills and Cable Factory (of which the fuel is diesel) where we propose to install a head recovery exchanger between the hot fumes out of the oven (60 C) and combustion air taken initially at room temperature (250C). Without recovery the oven consumes on the average 101 liters of diesel per hour for its operation and yields a thermal efficiency of 68,6%. Whereas with recovery, it can reach a thermal efficiency of 86% on one of recoverers that we have proposed, and save up to 15,8 liters of diesel on its hourly consumption

131

Investigation on Temperature Change of Cold Magnesium Alloy Strips Rolling Process with Heated Roll  

Science.gov (United States)

Magnesium alloy strips are widely used in aerospace, automotive industry, etc., which are difficult to produce through cold forming process due to their poor deformation ability. In this article, we studied whether the rolling process with heated roll could be used to roll cold magnesium alloy strips. Thermal-mechanical finite element simulation of the rolling process, using heated roll and cold strips to produce the magnesium alloy strips, was carried out. Influences of roll temperature, rolling velocity, rolling reduction ratio, and initial strip thickness on the thermal field and the mean temperature of magnesium alloy strips were analyzed. Both the heated area in strips in rolling deformation zone and the mean temperature of strips at exit of rolling deformation zone increase with increasing the roll temperature and/or rolling reduction ratio, and/or with decreasing the rolling velocity and/or initial strip thickness. Finally, a formula was developed to predict the mean temperature of strips under different rolling conditions, which also could be used to calculate the critical value of parameters in rolling process.

Yu, Hai-liang; Yu, Qing-bo; Kang, Jin-wu; Liu, Xiang-hua

2012-09-01

132

Almost rolling motion: An investigation of rolling grooved cylinders  

CERN Document Server

We examine the dynamics of cylinders that are grooved to form N teeth for rolling motion down an inclined plane. The grooved cylinders are experimentally found to reach a terminal velocity. This result can be explained by the inclusion of inelastic processes which occur whenever a tooth hits the surface. The fraction of the angular velocity that is lost during an inelastic collision is phenomenologically found to be proportional to (2*sin^2*pi/N)-(alpha*sin^3*pi/N), and the method of least squares is used to find the constant alpha=0.98. The adjusted theoretical results for the time of rolling as well as for terminal velocity are found to be in good agreement with the experimental results.

Mead, L R; Mead, Lawrence R.; Bentrem, Frank W.

1998-01-01

133

Roll-to-roll fabrication of polymer solar cells  

Directory of Open Access Journals (Sweden)

Full Text Available As the performance in terms of power conversion efficiency and operational stability for polymer and organic solar cells is rapidly approaching the key 10–10 targets (10 % efficiency and 10 years of stability the quest for efficient, scalable, and rational processing methods has begun. The 10–10 targets are being approached through consistent laboratory research efforts, which coupled with early commercial efforts have resulted in a fast moving research field and the dawning of a new industry. We review the roll-to-roll processing techniques required to bring the magnificent 10–10 targets into reality, using quick methods with low environmental impact and low cost. We also highlight some new targets related to processing speed, materials, and environmental impact.

Roar Søndergaard

2012-01-01

134

Towards roll-to-roll manufacturing of polymer photonic devices  

Science.gov (United States)

Traditionally, polymer photonic devices are fabricated using clean-room processes such as photolithography, e-beam lithography, reactive ion etching (RIE) and lift-off methods etc, which leads to long fabrication time, low throughput and high cost. We have utilized a novel process for fabricating polymer photonic devices using a combination of imprinting and ink jet printing methods, which provides high throughput on a variety of rigid and flexible substrates with low cost. We discuss the manufacturing challenges that need to be overcome in order to realize true implementation of roll-to-roll manufacturing of flexible polymer photonic systems. Several metrology and instrumentation challenges involved such as availability of particulate-free high quality substrate, development and implementation of high-speed in-line and off-line inspection and diagnostic tools with adaptive control for patterned and unpatterned material films, development of reliable hardware, etc need to be addressed and overcome in order to realize a successful manufacturing process. Due to extreme resolution requirements compared to print media, the burden of software and hardware tools on the throughput also needs to be carefully determined. Moreover, the effect of web wander and variations in web speed need to accurately be determined in the design of the system hardware and software. In this paper, we show the realization of solutions for few challenges, and utilizing these solutions for developing a high-rate R2R dual stage ink-jet printer that can provide alignment accuracy of <10?m at a web speed of 5m/min. The development of a roll-to-roll manufacturing system for polymer photonic systems opens limitless possibilities for the deployment of high performance components in a variety of applications including communication, sensing, medicine, agriculture, energy, lighting etc.

Subbaraman, Harish; Lin, Xiaohui; Ling, Tao; Guo, L. Jay; Chen, Ray T.

2014-03-01

135

Roll Casting of Al-25%Si  

International Nuclear Information System (INIS)

Strip casting of Al-25%Si strip was tried using an unequal diameter twin roll caster. The diameter of the lower roll (large roll) was 1000 mm and the diameter of the upper roll (small roll) was 250 mm. Roll material was mild steel. The sound strip could be cast at the speeds ranging from 8 m/min to 12 m/min. The strip did not stick to the roll without the parting material. The primary Si, which existed at centre area of the thickness direction, was larger than that which existed at other area. The size of the primary Si was smaller than 0.2 mm. Eutectic Si was smaller 5 ?m. The as-cast strip was ranging from 2 mm to 3 mm thick and its width was 100 mm. The as-cast strip could be hot rolled down to 1 mm. The hot rolled strip was cold rolled. The primary Si became smaller and the pore occurred around the primary Si after the rolling.

136

Utilization of stellite registered rolls  

International Nuclear Information System (INIS)

In the time period 2005-2006 the guidance rolls were removed from 129 used control elements of the NPP Brunsbuettel by the Gamma-Service Recycling GmbH (GSR) with the aim to recycle the material for the production of radiation sources. The authors describe the dismantling of the control elements that are made of f stellite registered with about 50% Co-59 (after irradiation Co-60). The 516 guidance rolls had a radioactive inventory of 8E14 Bq. The material was packaged and transported in underwater-boxes in MOSAIK registered /-type containers. The recycling process was performed in the hot cells of the Helmholtz Center Berlin. Rod-type radiation sources (type R38) were produced for industrial application (medical equipment sterilization, radiation-induced polymerization, food industry, etc.)

137

Finite element analysis of roll bit behaviors in cold foil rolling process  

Science.gov (United States)

To investigate roll bite behaviors in cold foil rolling process, a 2D elasto-plastic finite model is established using FEM software ABAQUS. Contact pressure distribution and roll contour in roll bite are also presented, which demonstrate that foil rolling process is different from conventional strip rolling process. The contact area is composed of entry elastic zone, entry plastic zone, an extensive neutral zone, exit plastic zone and exit elastic zone. It conforms to the results of Fleck foil rolling theory. Elastic deformation and work hardening of foil in roll bite are taken into account. The effect of rolling parameters, such as friction coefficient, entry thickness and reduction rate on distribution of contact pressure and vertical displacement are also discussed.

Hao, Liang; Jiang, Zhengyi; Wei, Dongbin; Chen, Xiawei

2013-05-01

138

The effect of roll gap geometry on microstructure in cold-rolled aluminum  

DEFF Research Database (Denmark)

Microstructure and texture are analyzed through the thickness of two aluminum plates cold-rolled 40% with different roll gap geometries. It is found that both texture and microstructure are strongly affected by the rolling geometry. After rolling with intermediate-size draughts a rolling-type texture is developed throughout the plate thickness. In this case, grains are subdivided by extended planar dislocation boundaries preferentially aligned at an angle of 40 +/- 15degrees to the rolling direction. In the plate rolled with small draughts, shear texture components appear in the intermediate layers. In these layers, extended planar dislocation boundaries are frequently found to be inclined closely to the rolling direction. The subsurface and central layers of this plate exhibit microstructures similar to those in the plate rolled with intermediate draughts. It is suggested that the development of different textures and microstructures at different depths is related to the activation of different slip systems due to through-thickness strain gradients.

Mishin, Oleg; Bay, B.

2004-01-01

139

Micromagnetic testing for rolled steel  

Digital Repository Infrastructure Vision for European Research (DRIVER)

In forming of steel by hot and cold rolling a broad range of semi-finished and final products can be produced with very specific, custom-tailored technological properties. Here, the characteristics of mechanical-technological tests (tensile, hardness, creep, fatigue test) are often of central importance. Obviously the traditionally process orientated steel industry has a strong interest to replace timeconsuming and expensive destructive mechanical tests by non-destructive (nd) methods, which ...

Wolter, B.; Dobmann, G.

2006-01-01

140

Rolling of power metallurgical gears  

Digital Repository Infrastructure Vision for European Research (DRIVER)

With the findings of this study surface defect densification defects and shape devia-tions can be avoided. Furthermore, the time for development of the rolling process can be shortened. Through a process analysis, the relationship between process input and process output was determined. The test gear is representative for automotive applications as well as suitable for fur-ther fatigue tests. An analogy process with cylindrical tools and cylindrical roller blanks was developed. The cylindrica...

Kauffmann, Philipp

2013-01-01

 
 
 
 
141

Rolling Contact Fatigue of Ceramics  

Energy Technology Data Exchange (ETDEWEB)

High hardness, low coefficient of thermal expansion and high temperature capability are properties also suited to rolling element materials. Silicon nitride (Si{sub 3}N{sub 4}) has been found to have a good combination of properties suitable for these applications. However, much is still not known about rolling contact fatigue (RCF) behavior, which is fundamental information to assess the lifetime of the material. Additionally, there are several test techniques that are employed internationally whose measured RCF performances are often irreconcilable. Due to the lack of such information, some concern for the reliability of ceramic bearings still remains. This report surveys a variety of topics pertaining to RCF. Surface defects (cracks) in Si{sub 3}N{sub 4} and their propagation during RCF are discussed. Five methods to measure RCF are then briefly overviewed. Spalling, delamination, and rolling contact wear are discussed. Lastly, methods to destructively (e.g., C-sphere flexure strength testing) and non-destructively identify potential RCF-limiting flaws in Si{sub 3}N{sub 4} balls are described.

Wereszczak, Andrew A [ORNL; Wang, W. [Bournemouth University, Bournemouth, United Kingdom; Wang, Y. [Bournemouth University, Bournemouth, United Kingdom; Hadfield, M. [Bournemouth University, Bournemouth, United Kingdom; Kanematsu, W. [National Institute of Advanced Industrial Science and Technology, Japan; Kirkland, Timothy Philip [ORNL; Jadaan, Osama M. [University of Wisconsin, Platteville

2006-09-01

142

A new transducer for local load measurements of friction and roll pressure in cold flat rolling  

DEFF Research Database (Denmark)

The only way to establish the true rolling pressure and the true friction condition in cold rolling is to conduct measurements in the roll bite. A new transducer design is therefore proposed, in order to overcome problems in previous measurements in the past 70 years. The new idea is to increase the contact surface of the transducer, to be larger than the arc of contact. This is in contrast to the smaller and smaller contact pin design that has been prevailing. The measurements were conducted during cold dry rolling of both copper strips and stainless steel strips in a pilot mill. The recordings were selected from a steady state with no disturbance from the material flow. The transducer was able to simultaneously measure both the normal pressure and the friction stress. An estimation of the coefficient of friction was accordingly performed. The new transducer works very well, it was seen to be robust and able to avoid signal disturbance. The pressure and friction stress distribution results was as expected bythe authors and showed good reproducibility, together with a proven agreement between recorded and simulated signals.

Lagergren, J.; Wanheim, Tarras

2006-01-01

143

Large-scale Evaluation of Nickel Aluminide Rolls in a Heat-Treat Furnace at Bethelehem Steel's (Now ISG) Burns Harbor Plate Mill  

Energy Technology Data Exchange (ETDEWEB)

At Bethlehem Steel Burns Harbor Plate Division (now ISG Burns Harbor Plate Inc.)'s annealing furnace, new nickel aluminide intermetallic alloy rolls provide greater high-temperature strength and wear resistance compared to the conventional H series cast austenitic alloys currently used in the industry. Oak Ridge National Laboratory and Bethlehem (ISG) partnered under a U.S. Department of Energy, Office of Industrial Technology's Emerging Technology Deployment Program to demonstrate and evaluate the nickel aluminide intermetallic alloy rolls as part of an updated energy efficient large commercial annealing furnace system. Many challenges were involved in this project, including developing welding procedures for joining nickel aluminide intermetallic alloys with H-series austenitic alloys, developing commercial cast roll manufacturing specifications, working with several commercial suppliers to produce a quantity of high quality, reproducible nickel aluminide rolls for a large steel industrial annealing furnace, installing and demonstrating the capability of the rolls in this furnace, performing processing trials to evaluate the benefits of new equipment and processes, and documenting the findings. Updated furnace equipment including twenty-five new automated furnace control dampers have been installed replacing older design, less effective units. These dampers, along with upgraded flame-safety control equipment and new AC motors and roll-speed control equipment, are providing improved furnace control and additional energy efficiency. Energy data shows up to a 34% energy reduction from baseline after the installation of upgraded furnace damper controls along with up to a 34% reduction in greenhouse gases, potential for an additional 3 to 6% energy reduction per campaign of light-up and shutdown, and a 46% energy reduction from baseline for limited trials of a combination of improved damper control and straight-through plate processing. The straight-through processing is now possible because of the nickel aluminide rolls which also provided plate product surface quality improvement that will allow the additional processing of surface critical material. Benefits also include associated large reductions in maintenance, reduction in spare rolls and associated component costs, and potential for greater through-put and productivity. Estimated project fuel cost reductions alone for processing 100,000 tons/yr through this furnace are almost $0.5 million/yr with the new dampers, and more than $600,000/yr with straight-through processing and new damper control, assuming natural gas prices of $6.00/MMBtu. The nickel aluminide rolls are competitively priced with conventional H series alloy rolls.

Mengel, J.

2003-12-16

144

Nonlinear Modulation of Travelling Rolls in Magnetoconvection  

CERN Document Server

Modulational dynamics of oscillatory travelling rolls in magnetoconvection is studied near the onset of a Hopf bifurcation. Using weakly nonlinear analysis, we derive an envelope equation of oscillatory travelling rolls in the plane perpendicular to an ambient vertical magnetic field.The envelope equation is the Davey-Stewartson (DS) equation with complex coefficients, from which we obtain criteria for the modulational (Benjamin-Feir) instability of oscillatory travelling rolls.

Matsuba, K; Nozaki, K; Matsuba, Kenichi; Imai, Kenji; Nozaki, Kazuhiro

1996-01-01

145

Efficient Circulation of Railway Rolling Stock  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Railway rolling stock (locomotives, carriages, and train units) is one of the most significant cost sources for operatorsof passenger trains, both public and private. Rolling stock costsare due to material acquisition, power supply, and material maintenance. The efficient circulation of rolling stock material is therefore one of the objectives pursued. In this paper we focus on the circulation of train units on a single line. In order to utilize the train units on this li...

Alfieri, A.; Groot, R.; Kroon, L. G.; Schrijver, A.

2002-01-01

146

ROLL OUT THE TALENT : Final project report  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The ROLL OUT THE TALENT project was born out of the desire to recognise and support the strengths of vocational students and to develop new and innovative operating models. ROLL OUT THE TALENT promoted regional cooperation between institutes and companies. The project produced operating and study path models that take into consideration the individual strengths of vocational students and the principles of lifelong learning. This is the final report of the ROLL OUT THE TALENT project, and ...

Eerola, Tuomas; Tuominen, Pirjo; Hakkarainen, Riitta-liisa; Laurikainen, Marja; Mero, Niina

2014-01-01

147

Large-area, continuous roll-to-roll nanoimprinting with PFPE composite molds  

Science.gov (United States)

Successful implementation of a high-speed roll-to-roll nanoimprinting technique for continuous manufacturing of electronic devices has been hindered due to lack of simple substrate preparation steps, as well as lack of durable and long lasting molds that can faithfully replicate nanofeatures with high fidelity over hundreds of imprinting cycles. In this work, we demonstrate large-area high-speed continuous roll-to-roll nanoimprinting of 1D and 2D micron to sub-100 nm features on flexible substrate using perfluoropolyether (PFPE) composite molds on a custom designed roll-to-roll nanoimprinter. The efficiency and reliability of the PFPE based mold for the dynamic roll-to-roll patterning process was investigated. The PFPE composite mold replicated nanofeatures with high fidelity and maintained superb mold performance in terms of dimensional integrity of the nanofeatures, nearly defect free pattern transfer and exceptional mold recovering capability throughout hundreds of imprinting cycles.

John, Jacob; Tang, YuYing; Rothstein, Jonathan P.; Watkins, James J.; Carter, Kenneth R.

2013-12-01

148

Fluid management in roll-to-roll nanoimprint lithography  

Science.gov (United States)

The key process parameters of UV roll-to-roll nanoimprint lithography are identified from an analysis of the fluid, curing, and peeling dynamics. The process includes merging of droplets of imprint material, curing of the imprint material from a viscous liquid to elastic solid resist, and pattern replication and detachment of the resist from template. The time and distances on the web or rigid substrate over which these processes occur are determined as function of the physical properties of the uncured liquid, the cured solid, and the roller configuration. The upper convected Maxwell equation is used to model the viscoelastic liquid and to calculate the force on the substrate and the torque on the roller. The available exposure time is found to be the rate limiting parameter and it is O(?Rho /uo), where R is the radius of the roller, ho is minimum gap between the roller and web, and uo is the velocity of the web. The residual layer thickness of the resist should be larger than the gap between the roller and the substrate to ensure complete feature filling and optimal pattern replication. For lower residual layer thickness, the droplets may not merge to form a continuous film for pattern transfer.

Jain, A.; Bonnecaze, R. T.

2013-06-01

149

Interactions Between Stably Rolling Leukocytes In Vivo  

CERN Document Server

We have characterized the two-dimensional spatial dependence of the hydrodynamic interactions between two adhesively rolling leukocytes in a live venule in the mouse cremaster muscle. Two rolling leukocytes were observed to slow each other down when rolling together in close proximity, due to mutual sheltering from the external blood flow in the vessel lumen. These results are in agreement with a previous study of leukocyte rolling interactions using carbohydrate-coated beads in a parallel-plate flow chamber and a detailed computer model of adhesion in a multicellular environment.

King, M R; Kim, M B; Sarelius, I H; King, Michael R.; Ruscio, Aimee D.; Kim, Michael B.; Sarelius, Ingrid H.

2003-01-01

150

Europarlamendi roll põllumajanduspoliitika kujundamisel / Andres Tarand  

Index Scriptorium Estoniae

Euroopa Parlamendi roll Euroopa Liidu ühtse põllumajandus- ja energiapoliitika kujundamisel. Põllumajanduslik aspekt energeetikas: energiasektori varustamine omamaa bioenergiaga, Venemaa energeetika välispoliitika teenistuses

Tarand, Andres, 1940-

2006-01-01

151

CRITICAL WAVE EPISODES FOR ASSESSMENT OF ROLL  

DEFF Research Database (Denmark)

The statistical distribution of parametric induced roll angles is estimated using the first order reliability method (FORM), well-known from structural reliability problems. To illustrate the proposed procedure the roll motion is modeled by a simplified non-linear procedure taking into account the time-varying restoring moment and the heave acceleration. The result is the mean outcrossing rate of the roll angle together with corresponding most probable wave scenarios (critical wave episodes), leading to specific maximum roll angles. The procedure is computationally very effective and can thus be applied for determination of ship specific combinations of heading, speed and sea states to be avoided.

Jensen, JØrgen Juncher; Pedersen, Preben Terndrup

2006-01-01

152

Toward Large Scale Roll-to-Roll Production of Fully Printed Perovskite Solar Cells.  

Science.gov (United States)

Fully printed perovskite solar cells are demonstrated with slot-die coating, a scalable printing method. A sequential slot-die coating process is developed to produce efficient perovskite solar cells and to be used in a large-scale roll-to-roll printing process. All layers excluding the electrodes are printed and devices demonstrate up to 11.96% power conversion efficiency. It is also demonstrated that the new process can be used in roll-to-roll production. PMID:25581092

Hwang, Kyeongil; Jung, Yen-Sook; Heo, Youn-Jung; Scholes, Fiona H; Watkins, Scott E; Subbiah, Jegadesan; Jones, David J; Kim, Dong-Yu; Vak, Doojin

2015-02-01

153

Roll pass design for improved flexibility and quality in wire rod rolling  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The thesis treats roll pass design in wire rod rolling of stainless steel for sequences and series built up by two-symmetrical grooves. It is focused on predicting rolling flexibility, also called working range, as well as product quality. For analysing the flexibility a computer program has been developed. The minimum and maximum roll gap and corresponding bar areas for series of grooves including "oval", "round", "false round", "square" and "diamond" shapes are calculated. Six pass designs ...

Eriksson, Conny

2004-01-01

154

Rolling-cuff flexible bellows  

Science.gov (United States)

A flexible connector apparatus used to join two stiff non-deformable members, such as piping, is described. The apparatus is provided with one or more flexible sections or assemblies each utilizing a bellows of a rolling cuff type connected between two ridge members, with the bellows being supported by a back-up ring, such that only the curved end sections of the bellows are unsupported. Thus, the bellows can be considered as being of a tube-shaped configuration and thus have high pressure resistance. The components of the flexible apparatus are sealed or welded one to another such that it is fluid tight.

Lambert, D.R.

1982-09-27

155

FEM Analysis of Effect of Rolling Parameters on Cold Rolling Process  

Directory of Open Access Journals (Sweden)

Full Text Available A FEM simulation study was carried out to investigate the influence of the rolling parameters on the rolling process. Using commercial FEM software, ABAQUS, a number of cases were studied. In this paper, a two-dimensional Elastic-plastic finite element model to simulate the cold rolling of thick strip with different roll angular velocity and roll diameter models is described. The angular velocity of the rigid rolls ranged from 30 to 480 revolutions per minute (r.p.m. and the rigid roll diameter ranged from 100 to 300 mm. The initial feeding speed of the plate and friction was kept constant, thus causing a slip between the plate and the roll surfaces. The main interest of this study is to see whether the speed of the rolls and the diameter of the rolls have any influence on the contact pressure and the residual stress in cold rolling process. The roll speed is an easily controlled operational parameter which may be used to enhance the process and the quality of the final products by changing the roller diameter and see the effect of stress and contact pressure on the thick plates strip is new one.

K. Devarajan

2012-03-01

156

Effect of temper rolling on final shape defects in a V-section roll forming process  

Science.gov (United States)

Roll forming is a continuous process in which a flat strip is shaped to the desired profile by sequential bending in a series of roll stands. Because of the large variety of applications of roll forming in the industry, Finite Element Analysis (FEA) is increasingly utilized for roll forming process design. Bending is the dominant deformation mode in roll forming. Sheet materials used in this process are generally temper rolled, roller- or tension- leveled. These processes introduce residual stresses into the material, and recent studies have shown that those affect the material behavior in bending. In this study a numerical model of the temper rolling (skin passing) process was used to determine a residual stress distribution in a dual phase, DP780, steel strip. A 5-stand roll forming process for the forming of a V-section was modeled, and the effect of various thickness reduction levels in the temper rolling process on the final shape defects was analyzed. The results show that a small thickness reduction in the temper rolling process decreases the maximum bow height but the final springback angle increases. It is also shown that reasonable model accuracy can be achieved by including the residual stress information due to temper rolling as initial condition in the numerical modeling of a roll forming process.

Abvabi, Akbar; Rolfe, Bernard; Hodgson, Peter D.; Weiss, Matthias

2013-12-01

157

49 CFR 661.11 - Rolling stock procurements.  

Science.gov (United States)

...2010-10-01 false Rolling stock procurements. 661...661.11 Rolling stock procurements. ...buses and other rolling stock (including train control, communication...advance the value or improve the condition of...

2010-10-01

158

High speed roll casting of Mg alloy strip by a vertical type twin roll caster  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Purpose: The possibility of high speed roll casting of AZ31, AM60 and AZ91 was investigated. Warm deep drawing of roll cast magnesium alloy was operated. and formability of roll cast magnesium strip was cleared.Design/methodology/approach: A vertical type high speed twin roll caster was used. The roll casting was operated in the air atmosphere. The casting speed was from 60 m/min up to 180 m/min. Low temperature casting was adopted to realize high speed casting.Findings: Strip thinner 3 mm wi...

Watari, H.; Kumai, S.; Haga, T.

2006-01-01

159

Assessment of air pollution and its effects on the health status of the workers in beam rolling mills factory (Iran National Steel Industrial Group from Ahvaz-Iran  

Directory of Open Access Journals (Sweden)

Full Text Available Background: Air pollutants of iron- and steel-making operations have historically been an environmental and health hazard. These pollutants include gaseous substances such as sulfur oxide, nitrogen dioxide, and carbon monoxide. The Iran National Steel Industrial Group beam rolling mills factory has two production lines viz. line 630 and line 650, with different beam production capabilities and is capable of producing different types of beams. Materials and Methods: A retrospective cross-sectional study on 400 workers in different exposure levels to environmental pollution was performed during 2005 to determine the mean value of respirable particulate matter (RPM concentrations and its effects on the health status of workers. To elicit information regarding the health status of the worker, the National Institute for Occupational Safety and Health standard questionnaire was used. Fisher?s exact test was performed to assess the relative risk (RR of exposure to air pollution on cardiovascular diseases, chest tightness, cough, difficulty in retention, i.e. loss of memory, tension, occupational fatigue, and occupational stress in exposed workers. Results: There was significant difference in RPM pollution level between two product lines. The RR of exposure to air pollution on cardiovascular diseases, chest tightness, cough, difficulty in retention, i.e. loss of memory, tension, occupational fatigue, and occupational stress in exposed workers were 2.78, 2.44, 2.15, 1.92, 1.57, 3.90, and 2.09, respectively.

Rafiei Masoud

2009-01-01

160

Hot rolling technology for producing high quality stainless steel at No.3 hot strip mill in Chiba works; Chiba seitetsusho daisan netsukan atsuen kojo ni okeru stainless ko no kohinshitsuka netsukan atsuen gijutsu  

Energy Technology Data Exchange (ETDEWEB)

This paper describes technologies to control cross sectional size and quality such as sheet thickness, crown and shape, and surface quality of hot rolled stainless steels, as well as the quality levels of the steels, manufactured at the No. 3 hot strip mill in Chiba Works (Chiba 3HOT) of Kawasaki Steel. The Chiba 3HOT started operation in May 1995. Dimensions, shape and quality of hot rolled stainless steel sheets produced in this mill have been improved greatly as a result of using high-accuracy response sheet thickness control, set-up control and dynamic control of high-accuracy crown and shape in a pair cross mill introduced with an on-line roll grinder, and control of flaws in edge seams. These controls have resulted in the following achievements: (1) stainless steels made of hard steel strips with high deformation and resistance were expanded of their sizes, and high-accuracy sheet thickness was achieved over the entire length of steels; (2) a high-accuracy crown and shape controlling technology for stainless steel sheets was developed to achieve low crown stably even under schedule-free operation; and (3) a technology was developed to reduce largely the edge-seam defects by using the sizing press. 10 refs., 13 figs.

Egawa, N.; Ishizuka, H.; Hiruta, T. [Kawasaki Steel Corp., Tokyo (Japan)

1998-08-01

 
 
 
 
161

Numerical analysis of Swiss roll metamaterials  

Energy Technology Data Exchange (ETDEWEB)

A Swiss roll metamaterial is a resonant magnetic medium, with a negative magnetic permeability for a range of frequencies, due to its self-inductance and self-capacitance components. In this paper, we discuss the band structure, S-parameters and effective electromagnetic parameters of Swiss roll metamaterials, with both analytical and numerical results, which show an exceptional convergence.

Demetriadou, A; Pendry, J B, E-mail: ademetri@imperial.ac.u, E-mail: j.pendry@imperial.ac.u [Blackett Laboratory, Imperial College London, London SW7 2AZ (United Kingdom)

2009-08-12

162

Numerical analysis of Swiss roll metamaterials.  

Science.gov (United States)

A Swiss roll metamaterial is a resonant magnetic medium, with a negative magnetic permeability for a range of frequencies, due to its self-inductance and self-capacitance components. In this paper, we discuss the band structure, S-parameters and effective electromagnetic parameters of Swiss roll metamaterials, with both analytical and numerical results, which show an exceptional convergence. PMID:21693980

Demetriadou, A; Pendry, J B

2009-08-12

163

Numerical analysis of Swiss roll metamaterials  

International Nuclear Information System (INIS)

A Swiss roll metamaterial is a resonant magnetic medium, with a negative magnetic permeability for a range of frequencies, due to its self-inductance and self-capacitance components. In this paper, we discuss the band structure, S-parameters and effective electromagnetic parameters of Swiss roll metamaterials, with both analytical and numerical results, which show an exceptional convergence.

164

Roll casting of 5182 aluminium alloy  

Directory of Open Access Journals (Sweden)

Full Text Available Purpose: of this paper is investigation of the ability of the high speed roll casting of 5182 aluminium alloy. Appropriate twin roll caster to cast the 5182 strip was researched.Design/methodology/approach: Method used in the present study was an unequal diameter twin roll caster and a vertical type high speed twin roll caster equipped with mild steel rolls without parting material.Findings: are that the vertical type high speed twin roll caster was effective to cast 5182 strip at high speed. 5182 could be cast at 10 times higher speed than a conventional twin roll caster for aluminium alloy. 5182 could be cast by the mild steel roll using no-parting material without sticking.Research limitations/implications: is that ability of casting of the wide strip, that is wider than 600 mm, could not be investigated.Practical implications: 600 mm-width 5182 strip could be cast and this width is enough for some structural parts. 5182 could be cast into the strip at high productivity and low energy using the economy equipment and no-consumable good.Originality/value: The method to make economy sheet metal of aluminium alloy is imported. The economy alloy and economy process are essential to get economy aluminium alloy sheet.

T. Haga

2009-06-01

165

A ball rolling down a rotating board  

Directory of Open Access Journals (Sweden)

Full Text Available This article describes an easily constructed apparatus for an experiment on a rolling ball a rotating board.From the experimental and theoretical results, we can find that the ball leaves the board at the instant boththe ball and the board are released from hand. Then, the ball can’t roll down the board until the balltouches the board again.

Akio Saitoh

2010-09-01

166

Rolling-Convolute Joint For Pressurized Glove  

Science.gov (United States)

Rolling-convolute metacarpal/finger joint enhances mobility and flexibility of pressurized glove. Intended for use in space suit to increase dexterity and decrease wearer's fatigue. Also useful in diving suits and other pressurized protective garments. Two ring elements plus bladder constitute rolling-convolute joint balancing torques caused by internal pressurization of glove. Provides comfortable grasp of various pieces of equipment.

Kosmo, Joseph J.; Bassick, John W.

1994-01-01

167

9 CFR 381.159 - Poultry rolls.  

Science.gov (United States)

...referred to in the preceding sentence, the following substances are permitted for use as binders in poultry rolls: transglutaminase enzyme at up to 65 ppm. When binding agents are added in excess of 3 percent for cooked rolls and 2 percent for...

2010-01-01

168

Surface defects on austenitic rolled steel  

International Nuclear Information System (INIS)

A study was made on the nature of surface defects of 12Kh2N4A, Kh18N10T, Kh23N18 and other rolled steels, the reasons of their formation and the methods for their prevention. It is shown that main types of surface defects are presented by fissures and cracks. The fissures are related to low metal plasticity, as well as to steel rolling at the temperature lower than recrystallization temperature. The use of differentiated conditions of heating ingots for rolling excludes completely these defects. Cracks are of different nature: the single ones form during rolling on ingots, casted carelessly; the grouped cracks are located along two antipodar rolling generatrices. They are characteristic for intermediate oval profile with low mechanical properties

169

Automated Procedure for Roll Pass Design  

Science.gov (United States)

The aim of this work has been to develop an automatic roll pass design method, capable of minimizing the number of roll passes. The adoption of artificial intelligence technologies, particularly expert systems, and a hybrid model for the surface profile evaluation of rolled bars, has allowed us to model the search for the minimal sequence with a tree path search. This approach permitted a geometrical optimization of roll passes while allowing automation of the roll pass design process. Moreover, the heuristic nature of the inferential engine contributes a great deal toward reducing search time, thus allowing such a system to be employed for industrial purposes. Finally, this new approach was compared with other recently developed automatic systems to validate and measure possible improvements among them.

Lambiase, F.; Langella, A.

2009-04-01

170

Aerodynamics of a rolling airframe missile  

Science.gov (United States)

For guidance-related reasons, there is considerable interest in rolling missiles having single-plane steering capability. To aid the aerodynamic design of these airframes, a unique investigation into the aerodynamics of a rolling, steering missile has been carried out. It represents the first known attempt to measure in a wind tunnel the aerodynamic forces and moments that act on a spinning body-canard-tail configuration that exercises canard steering in phase with body roll position. Measurements were made with the model spinning at steady-state roll rates ranging from 15 to 40 Hz over an angle-of-attack range up to about 16 deg. This short, exploratory investigation has demonstrated that a better understanding and a more complete definition of the aerodynamics of rolling, steering vehicles can be developed by way of simulative wind-tunnel testing.

Tisserand, L. E.

1981-05-01

171

High speed roll casting of Mg alloy strip by a vertical type twin roll caster  

Directory of Open Access Journals (Sweden)

Full Text Available Purpose: The possibility of high speed roll casting of AZ31, AM60 and AZ91 was investigated. Warm deep drawing of roll cast magnesium alloy was operated. and formability of roll cast magnesium strip was cleared.Design/methodology/approach: A vertical type high speed twin roll caster was used. The roll casting was operated in the air atmosphere. The casting speed was from 60 m/min up to 180 m/min. Low temperature casting was adopted to realize high speed casting.Findings: Strip thinner 3 mm with 100 width could be cast continuously. The casting ability became better with increasing content of Al. Roll cast Mg alloy strips could be hot-rolled down to 0.5 mm. AZ31 as-cast strip could be thinner down to 0.5 mm only by three times of hot rolling. Deep drawing was operated with three kinds of Mg alloy at 250°C, and LDR value was larger than 2.0. It was shown that deep drawing of AZ91 alloy for casting was possible.Research limitations/implications: There was tendency that cracks occurred at the center in the thickness direction as Al content increased.Practical implications: Sheet metal forming of magnesium alloy with high content Al can be realized.Originality/value: It was shown that possibility of high speed roll casting of magnesium alloy, and warm deep drawing of roll cast AZ91 strip.

H. Watari

2006-02-01

172

Flow Stress Evaluation in Hot Rolling of Steel  

Science.gov (United States)

In this paper, an inverse analysis technique is used to obtain the flow curve of materials in a hot rolling finishing mill. This technique is based on minimization of the differences between the experimental and computed values. The flow curves and the friction coefficients at roll/work-piece interface are derived from two different models. Model I is based on simple slab method of analysis. Model II is based on a modified slab method in which the effect of shear stress in calculating the rolling force and torque is taken into account. It is shown that the developed inverse analysis technique is reliable and can simultaneously determine a more accurate flow stress for the material as well as a better estimation for the interface friction factors.

Aghasafari, P.; Salimi, M.; Daraei, A.

2014-08-01

173

Experimental study of interfacial heat flux and surface temperature by inverse analysis with thermocouple (fully embedded) during hot steel strip rolling  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Knowledge of temperature distribution in the roll is fundamental aspect in cold rolling. An inverse analytical method has been previously developed to determine interfacial heat flux and surface temperature by measuring the temperature with a thermocouple (fully embedded) at only one point inside the roll. On this basis some pilot mill tests have been performed. The temperature sensor, the calibration procedure and rolling tests at different strip rolling conditions (5%, 10%, 15% and 20%) are...

Weisz-patrault, Daniel; Ehrlacher, Alain; Legrand, Nicolas; Labbe, Nathalie; Horsky, Jaroslav; Luks, Tomas

2012-01-01

174

Signal and power roll ring testing update  

Science.gov (United States)

The development of the roll ring as a long-life, low-torque alternative to the slip ring is discussed. A roll ring consists of one or more circular flexures captured by their own spring force in the annular space between two concentric conductors or contact rings. The advantages of roll rings over other types of electrical transfer devices are: extremely low drag torque, high transfer efficiencies in high-power configurations, extremely low wear debris generation, long life, and low weight for high-power applications.

Smith, Dennis W.

1989-01-01

175

Twin roll casting of magnesium alloys with high aluminum contents  

Directory of Open Access Journals (Sweden)

Full Text Available Purpose: The purpose of the work is to establish a manufacturing process and technology to facilitate theeconomical manufacture of high-quality magnesium sheet alloys with high aluminum contents, such as AZ61and AZ91. The aim of the work is to establish a twin roll casting technology to facilitate the manufacture ofAZ61 and AZ91 magnesium sheet alloys economically whilst maintaining high quality.Design/methodology/approach: A horizontal type twin roll caster was used to manufacture thin magnesium alloysheets of AZ61 and AZ91. Pair of copper alloy roll and pure copper roll was used for the horizontal type twin roll caster.A closed type tundish was set to the roll caster to keep stable contact of molten magnesium with upper and lower rolls.Findings: The experiment results clarified that AZ61 and AZ91 sheets can be manufactured by twin roll castingprocess. The product sheet thickness in the present experiment is 2.0 to 4.5 mm for AZ91, 2.5 to 5.0mm forAZ61. Mill stiffness and a method of predicting the cast sheet’s thickness were investigated to determine theappropriate manufacturing conditions. The microstructure of AZ61 cast strips was equiaxed structure and thecrystal sizes are different depending on cross section observed. The dendric and equiaxed microstructure wereseen in the microstructure of AZ91 cross section. The intermetllic Mg17Al12 was seen in the grain boundary inAZ91 when roll speed was very slow. The grain size of the manufactured wrought magnesium alloys sheet wasless than 10 micrometers. The obtained magnesium alloy sheet exhibited an equivalent limiting drawing ratio ina warm-drawing test. The limiting drawing ratio of AZ61 was 2.6 and 2.4 for AZ91.Research limitations/implications: The suitable roll speed was from 9m/min to 15m/min in manufacturingAZ91 and AZ61 strip using copper alloy rolls. When in use of pure copper roll, strips were cast between 6m/minand 20m/min for manufacturing AZ61 and AZ91. The superheats in the experiment were 15ºC and 30ºC. Thecast strips should be hot rolled at 300ºC.Originality/value: value In this experiment, it is clarified that AZ61, AZ91 sheets can be manufactured by twinroll casting. These cast sheet can be hot rolled and the manufacturing process by twin roll casting enable tomanufacure thin magnesium sheet alloys with high aluminum contents. It has been found that the manufacturedcast AZ61 and AZ91 have good formability by a warm deep drawing test.

H. Watari

2006-08-01

176

Recrystallization texture characteristic and drawability of a warm rolled and cold rolled interstitial-free steel  

Science.gov (United States)

The recrystallization textures and drawability in an interstitial-free (IF) steel were investigated as a function of cold rolling reduction. The hot bands for further cold rolling were obtained by lubricated hot rolling in the ferrite region. The orientation distribution function (ODF) was applied to analyze recrystallization textures. Texture analysis showed that hot bands rolled in the ferrite region had strong {111}//ND texture component. The {111}//ND recrystallization texture of the cold rolled steel with 73% reduction displayed the highest intensity, but weakened as more cold work was introduced. The highest r-value was obtained at a cold reduction of 73% when the hot band was previously rolled in the ferrite region.

Wang, Zhaodong; Guo, Yanhui; Liu, Xianghua; Wang, Guodong; Zhang, Peng

2006-12-01

177

Development of rolling textures in aluminum alloy 3004 subjected to varying hot-rolling deformation  

Science.gov (United States)

The influence of temperature and strain on texture development in aluminum alloy AA 3004 has been studied in a series of multipass rolling experiments. Temperature had no discernible effect on texture development except through its interactive effects with roll chilling and interpass reheat recrystallization. Some literature-based predictions of rolling textures were in good agreement with the experimental data. The cube texture was formed in small quantities during the interpass reheat recrystallization.

Hollinshead, P. A.; Sheppard, T.

1989-08-01

178

25 CFR 75.15 - Current membership roll.  

Science.gov (United States)

...2010-04-01 2010-04-01 false Current membership roll. 75.15 Section 75.15... TRIBAL GOVERNMENT REVISION OF THE MEMBERSHIP ROLL OF THE EASTERN BAND OF CHEROKEE...NORTH CAROLINA § 75.15 Current membership roll. The membership roll...

2010-04-01

179

9 CFR 381.159 - Poultry rolls.  

Science.gov (United States)

...2010-01-01 2010-01-01 false Poultry rolls. 381.159 Section 381...AND TERMINOLOGY; MANDATORY MEAT AND POULTRY PRODUCTS INSPECTION AND VOLUNTARY INSPECTION AND CERTIFICATION POULTRY PRODUCTS INSPECTION REGULATIONS...

2010-01-01

180

Rolling tachyon in NS string field theory  

International Nuclear Information System (INIS)

A brief review of studing rolling solutions to equations of motion for the tachyon field living on an unstable D-brane in the level truncated string field theory is given. (Abstract Copyright [2003], Wiley Periodicals, Inc.)

 
 
 
 
181

The rolling and skidding of automobile tyres  

Science.gov (United States)

This article deals in simple terms with the rolling and skidding of automobile tyres. It shows that skid resistance on slippery road surfaces may be significantly increased by using tyre treads of high hysteresis loss.

Tabor, D.

1994-09-01

182

9 CFR 381.159 - Poultry rolls.  

Science.gov (United States)

...AGRICULTURE AGENCY ORGANIZATION AND TERMINOLOGY; MANDATORY MEAT AND POULTRY PRODUCTS INSPECTION AND VOLUNTARY INSPECTION AND...substances are permitted for use as binders in poultry rolls: transglutaminase enzyme at up to 65 ppm. When binding agents are added in...

2010-01-01

183

A high sensitive roll angle interferometer  

Science.gov (United States)

A roll angle interferometer with high sensitivity is designed in this paper. Two sets of centrosymmetric beams are used to travel through the measurement and reference arms of the roll angle interferometer which contains two specific optical devices: wedge prism assembly and wedge mirror assembly. The optical path change in both arms caused by roll is converted into phase shift which can be measured by interferometer. Because of the adoption of the centrosymmetric measurement structure, the straightness errors, yaw error and pitch error can be avoided and the dead path is minimized, so that the stability and the accuracy of the measurement can be greatly enhanced. The resolution for the roll measurement is about 0.006? with the measurement range of ±1°.

Le, Yanfen; Hou, Wenmei; Hu, Kai; Ju, Aisong

2013-01-01

184

DEVELOPMENT TRENDS FOR ROLLING STOCK TRACTION MOTORS  

Directory of Open Access Journals (Sweden)

Full Text Available Rolling stock on the railways of Ukraine has not been updated for many years, which has led to significant wear of the country electric and diesel locomotive fleet. A way out of the existing situation is execution of major overhaul with extension of locomotive life to allow their operation for several more years. Repair or upgrading as well as putting new rolling stock into operation must be accompanied by implementation of state-of-the-art traction electric drives.

O.V. Pasko

2013-02-01

185

Round rolling process of spur gears  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The paper deals with the rolling process of gears and profiles, which demonstrates a seminal energy and material efficient forming technology for the production of lead geometries of Power Train applications. Former cold rolling processes for gear production only gained industrial acceptation for assortments of stub-toothed geometries until a tooth height factor of y = 1.5. Results and findings of the researches at the Fraunhofer Institute for Machine Tools and Forming Technology Chemnitz pro...

Neugebauer, Reimund; Mu?ller, Roland; Hellfritzsch, Udo; Lahl, Mike; Schiller, Sven; Milbrandt, Matthias; Druwe, Thomas

2011-01-01

186

Disk partition function and oscillatory rolling tachyons  

International Nuclear Information System (INIS)

An exact cubic open string field theory rolling tachyon solution was recently found by Kiermaier et al and Schnabl. This oscillatory solution has been argued to be related by a field redefinition to the simple exponential rolling tachyon deformation of boundary conformal theory. In the latter approach, the disk partition function takes a simple form. Out of curiosity, we compute the disk partition function for an oscillatory tachyon profile, and find that the result is nevertheless almost the same

187

Characteristics of cold rolled stainless steel sheets  

International Nuclear Information System (INIS)

The cold rolling of sheets of austenitic stainless steel was investigated for different temperatures and percentages of reduction. It was also established under which conditions are the mechanical strenght and the ductility improved. It was found that this improvement is related to the characteristics of martensitic transformation taking place during rolling and through the tensile tests performed in stainless steels with different degree of martensitic transformation. The results are explained on the basis of martensite participation in the stained structure. (Author)

188

Partition Decomposition for Roll Call Data  

CERN Document Server

In this paper we bring to bear some new tools from statistical learning on the analysis of roll call data. We present a new data-driven model for roll call voting that is geometric in nature. We construct the model by adapting the "Partition Decoupling Method," an unsupervised learning technique originally developed for the analysis of families of time series, to produce a multiscale geometric description of a weighted network associated to a set of roll call votes. Central to this approach is the quantitative notion of a "motivation," a cluster-based and learned basis element that serves as a building block in the representation of roll call data. Motivations enable the formulation of a quantitative description of ideology and their data-dependent nature makes possible a quantitative analysis of the evolution of ideological factors. This approach is generally applicable to roll call data and we apply it in particular to the historical roll call voting of the U.S. House and Senate. This methodology provides a...

Leibon, Greg; Rockmore, Daniel N; Savell, Robert

2011-01-01

189

Strip edge cracking simulation in cold rolling  

International Nuclear Information System (INIS)

This research work focuses on a specific defect which occurs during cold rolling of steel strips: edge-serration. Investigations on the industrial processes have led to the conclusion that this defect is the result of the edge-trimming and cold rolling sequences. The aim of this research work is to analyze the effect of the cutting process and the cold rolling on cracks occurrence, especially on strip edges.This study is performed using an experimental testing stand called Upsetting Rolling Test (URT). It allows to reproduce cold rolling contact parameters such as forward slip, reduction ratio and friction coefficients. Specimens sampled near trimmed industrial strip edges are deformed using the URT stand. Two sets of specimens with different stress states, obtained by annealing, are submitted to two reduction passes with extreme forward slips.Scanning electron microscopy observations added to 3D optical surface profiler topographies show that on one hand, forward slip has a major effect on cracks opening. On the other hand, cracks opening decreases according to high roll strip speed gradient. Concerning the heat-treated specimens, no crack appeared after all reduction passes, showing a large influence of the cutting process and consequently of the local stress state in the vicinity of the burnish and fracture regions.

190

Strip edge cracking simulation in cold rolling  

Science.gov (United States)

This research work focuses on a specific defect which occurs during cold rolling of steel strips: edge-serration. Investigations on the industrial processes have led to the conclusion that this defect is the result of the edge-trimming and cold rolling sequences. The aim of this research work is to analyze the effect of the cutting process and the cold rolling on cracks occurrence, especially on strip edges. This study is performed using an experimental testing stand called Upsetting Rolling Test (URT). It allows to reproduce cold rolling contact parameters such as forward slip, reduction ratio and friction coefficients. Specimens sampled near trimmed industrial strip edges are deformed using the URT stand. Two sets of specimens with different stress states, obtained by annealing, are submitted to two reduction passes with extreme forward slips. Scanning electron microscopy observations added to 3D optical surface profiler topographies show that on one hand, forward slip has a major effect on cracks opening. On the other hand, cracks opening decreases according to high roll strip speed gradient. Concerning the heat-treated specimens, no crack appeared after all reduction passes, showing a large influence of the cutting process and consequently of the local stress state in the vicinity of the burnish and fracture regions.

Hubert, C.; Dubar, L.; Dubar, M.; Dubois, A.

2011-01-01

191

78 FR 69316 - Airworthiness Directives; Rolls-Royce Deutschland Ltd & Co KG (Formerly Rolls-Royce Deutschland...  

Science.gov (United States)

...Directives; Rolls-Royce Deutschland Ltd & Co KG (Formerly Rolls-Royce Deutschland GmbH...to all Rolls-Royce Deutschland Ltd & Co KG (RRD) BR700-715A1-30, BR700-715B1-30...contact Rolls-Royce Deutschland Ltd & Co KG, Eschenweg 11, Dahlewitz, 15827...

2013-11-19

192

ROLLING PROCESS WITH OHSAS AND TEXTURE FORMATION– A REVIEW  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Rolling is a mechanical treatment, which plays an important part in the processing of ferrous and nonferrous alloys. Texturing is an important phenomenon that occurs after rolling process. Preferred orientation increases the strength of the material enormously. Hence the research is focused on the rolling studies and the texture formation, which occurs after rolling process. This review mainly focuses on rolling process carried out in different alloys. It also highlights the analysis made on ...

Chandramohan, P.; Manikanda Subramanian, K.; Chandrasekar, P.

2009-01-01

193

Optimization of cold rolling process parameters in order to increasing rolling speed limited by chatter vibrations  

Directory of Open Access Journals (Sweden)

Full Text Available Chatter has been recognized as major restriction for the increase in productivity of cold rolling processes, limiting the rolling speed for thin steel strips. It is shown that chatter has close relation with rolling conditions. So the main aim of this paper is to attain the optimum set points of rolling to achieve maximum rolling speed, preventing chatter to occur. Two combination methods were used for optimization. First method is done in four steps: providing a simulation program for chatter analysis, preparing data from simulation program based on central composite design of experiment, developing a statistical model to relate system tendency to chatter and rolling parameters by response surface methodology, and finally optimizing the process by genetic algorithm. Second method has analogous stages. But central composite design of experiment is replaced by Taguchi method and response surface methodology is replaced by neural network method. Also a study on the influence of the rolling parameters on system stability has been carried out. By using these combination methods, new set points were determined and significant improvement achieved in rolling speed.

Ali Heidari

2013-01-01

194

Roll-to-roll fabricated lab-on-a-chip devices  

DEFF Research Database (Denmark)

We present a high-volume fabrication technique for making polymer lab-on-a-chip devices. Microfluidic separation devices, relying on pinched flow fraction, are roll-to-roll fabricated in a cellulose acetate (CA) film at a volume of 360 devices h?1 for a cost of approximately 0.5 euro/device. The manufacturing process consists of two steps: (i) roll-to-roll thermal nanoimprint for patterning the microchannels into a CA film and (ii) roll-to-roll lamination for bonding another CA film onto the imprinted film to seal the microchannels. Reverse gravure coating is used to apply an adhesive polymer onto the CA lid film before roll-to-roll lamination in order to increase the bonding strength. The fabricated devices are compared with planar imprinted devices with regard to the cross-sectional profile of the imprinted channels and their separation functionality. The separation functionality is characterized using fluorescent polystyrene microspheres with diameters ranging from 0.5 to 5 µm.

Vig, Asger Laurberg; Mäkelä, Tapio

2011-01-01

195

Sensitivity analysis of roll load, torque and material properties in the roll forming process  

Science.gov (United States)

Advanced High Strength Steel (AHSS) and Ultra High Strength Steel (UHSS) are increasingly used in the current automotive industry because of their high strength and weight saving potential. As a sheet forming process, roll forming is capable of forming such materials with precise dimensions, however a small change in processing may results in significant change in the material properties such as yield strength and hardening exponent from coil to coil or within the same coil. This paper presents the effect of yield strength and the hardening exponent on roll load, torque of the roll forming process and the longitudinal bow. The roll forming process is numerically simulated, and then the regression analysis and Analysis of Variance (ANOVA) techniques are employed to establish the relationships among the aforementioned parameters and to determine the percentage influence of material properties on longitudinal bow, roll load and torque.

Abeyrathna, Buddhika; Rolfe, Bernard; Hodgson, Peter; Weiss, Matthias

2013-12-01

196

Microstructure Evolution During Spray Rolling and Heat Treatment of 2124 Al  

Energy Technology Data Exchange (ETDEWEB)

Spray rolling is a strip casting technology that combines elements of spray forming and twin-roll casting. It consists of atomizing molten metal with a high velocity inert gas, quenching the resultant droplets in flight, and directing the spray between mill rolls. In-flight convection heat transfer from atomized droplets and conduction heat transfer at the rolls rapidly move an alloy’s latent heat. Hot deformation of the semi-solid material in the rolls results in fully consolidated, rapidly-solidified product. While similar in many ways to twin-roll casting, spray rolling is able to process a broader range of alloys and operates at a higher production rate. A laboratory-scale strip caster has been constructed at INL and used to evaluate the interplay of processing parameters and strip quality while producing strips up to 200 mm wide and 1.6 – 6.4 mm thick. Plans are underway to scale to 600 mm width and demonstrate steady-state operation. As-spray-rolled strip is characterized by a flat, uniformly thick profile with minimal porosity or segregation. This paper examines how processing parameters influence the microstructure transformations that take place during spray rolling and post-deposition heat treatment of 2124 Al.

K.M. McHugh; Y. Lin; Y. Zhou; S.B. Johnson; J.P. Delplanque; E.J. Lavernia

2006-09-01

197

The thermal and metallurgical state of steel strip during hot rolling: Part I. Characterization of heat transfer  

Science.gov (United States)

A technique using intrinsic thermocouples was developed to monitor the thermal response of steel samples during hot rolling. A series of hot-rolling tests was conducted with the thermocoupleinstrumented samples on CANME’s pilot mill to simulate individual stands of Stelco’s Lake Erie Works hot-strip mill. A mathematical model of heat transfer in the roll bite has been employed to back calculate the roll/strip interface heat-transfer coefficients for lubricated and unlubricated conditions. The influence of reduction, rolling speed, and prerolling on roll-strip heat transfer has also been examined. For unlubricated rolling tests, the heat-transfer coefficient in the roll bite increased with time, reaching a steady-state value of 57 kW/m2 °C. The corresponding number for the lubricated tests was 31 kW/m2 °C. The observed variation in the interface heat-transfer coefficient with increasing strain and interface pressure points to a strong dependence on the real area of contact between the strip and rolls. Therefore, it appears that heat transfer between the two surfaces occurs primarily by conduction across asperity contacts. The high heat-transfer coefficients attained at the roll/strip interface promote chilling of the strip to a depth of approximately one-eighth of the thickness. To validate the overall heattransfer model, predicted surface temperatures of the strip have been compared with interstand temperature measurements obtained on the industrial mill using pyrometers.

Devadas, C.; Samarasekera, I. V.; Hawbolt, E. B.

1991-02-01

198

Development of a twin roll caster for light metals  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Purpose: Purpose of this paper is to show the development of a twin roll caster for aluminium alloy. One of the developments was the increase of the roll speed. The increase of the roll speed was essential to improve the low productivity of the twin roll caster. Limitation of the alloys, which can be cast into the strip, could be enlarged by the method to increase the roll speed. The method to increase the roll speed was useful to increase the cooling rate of the cast strip. The devices to in...

Haga, T.

2010-01-01

199

Influence of sway motion on passive anti-rolling tank  

Science.gov (United States)

The passive anti-rolling tank is one of important ship stabilizers widely used today. But at present, research of the tank is most aimed at its rolling movement. In this paper, the influence of sway motion on the passive anti-rolling tank is considered, the mathematical model of “ship-passive anti-rolling tank” system coupled with sway motion is developed basing on the U-shaped passive anti-rolling tank theory. Both simulation results and experimental data indicate that it is necesary to consider the influence of sway motion on the anti-rolling tank, which is more agreeble to the actual circumstance

Sun, Wei; Liang, Li-Hua; Zhang, Hong

2006-03-01

200

An analytical approach to asymmetrical cold strip rolling using the slab method  

Science.gov (United States)

An analytical model for general asymmetrical cold rolling is proposed to investigate the behavior of sheet during asymmetrical rolling using the slab analysis. Neutral points between the upper and lower rolls and the strip, rolling pressure distribution along the contact interface of the roll and strip, and rolling forces, as well as rolling torque, can be calculated easily using this model. Rolling pressure distribution, rolling force, and rolling torque, which are affected by various rolling conditions such as roll speed ratio, thick-ness reduction, front and back tension, etc., are analyzed. Additionally, the limiting rolling conditions be-tween reduction and roll speed ratio, or front and back tension, under which the rolling process can be accomplished successfully, are discussed. By comparing analytical results and experimental measure-ments of rolling force, it is apparent that the proposed model can successfully provide useful knowledge for designing the pass schedule of the asymmetrical cold strip rolling process.

Hwang, Y.-M.; Tzou, G.-Y.

1993-08-01

 
 
 
 
201

Detection of Parametric Roll on Ships  

DEFF Research Database (Denmark)

Recent years have shown several incidents with dramatic damage on container vessels caused by parametric resonance. When the resonance starts, the roll oscillation at a sub-harmonic frequency of the wave excitation may be completely unexpected. Timely warning about the onset of the resonance phenomenon could make the navigator change ship’s speed and heading, and these remedial actions could make the vessel escape the bifurcation. This chapter proposes non-parametric methods to detect the onset of parametric roll resonance. Theoretical conditions for parametric resonance are re-visited and signal-based methods are developed to detect its onset. Hypothesis testing is derived for the particular distribution of the indicators for resonance. Robustness is investigated by analyzing forced roll and disturbances in real weather conditions. The performance of the novel methods is demonstrated on experimental data from towing tank tests and data from a container ship passing an Atlantic storm.

Galeazzi, Roberto; Blanke, Mogens

2012-01-01

202

Rolling Element Bearing Stiffness Matrix Determination (Presentation)  

Energy Technology Data Exchange (ETDEWEB)

Current theoretical bearing models differ in their stiffness estimates because of different model assumptions. In this study, a finite element/contact mechanics model is developed for rolling element bearings with the focus of obtaining accurate bearing stiffness for a wide range of bearing types and parameters. A combined surface integral and finite element method is used to solve for the contact mechanics between the rolling elements and races. This model captures the time-dependent characteristics of the bearing contact due to the orbital motion of the rolling elements. A numerical method is developed to determine the full bearing stiffness matrix corresponding to two radial, one axial, and two angular coordinates; the rotation about the shaft axis is free by design. This proposed stiffness determination method is validated against experiments in the literature and compared to existing analytical models and widely used advanced computational methods. The fully-populated stiffness matrix demonstrates the coupling between bearing radial, axial, and tilting bearing deflections.

Guo, Y.; Parker, R.

2014-01-01

203

Microstructural heterogeneity of forged rolled rings  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Purpose: The paper presents the processes which condition the quality of steel cast strands and properties of rolled products. It touches upon the technology of small-size rings manufacture from the 42CrMo4 steel used for the production of rolling bearings and toothed rings.Design/methodology/approach: Investigations were made on the 42CrMo4 steel based process of small-size rings manufacture of weight not exceeding 100 kg and the internal diameter up to 600 mm.Findings: Microstructure hetero...

Herian, J.

2007-01-01

204

Roll ring assemblies for the Space Station  

Science.gov (United States)

Space Station Freedom requires the transmission of high power and signals through three different rotational interfaces. Roll ring technology was baselined by NASA for rotary joints to transfer up to 65.5 kW of power for 30 years at greater than 99 percent efficiency. Signal transfer requirements included MIL-STD-1553 data transmission and 4.5 MHz RS250A base and color video. A unique design for each rotary joint was developed and tested to accomplish power and signal transfer. An overview of roll ring technology is presented, followed by design requirements, hardware configuration, and test results.

Batista, J.; Vise, J.; Young, K.

1994-01-01

205

Transient resonance of rolling finned projectiles  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Finned projectiles that are intentionally spun are known to become locked in at a resonance condition where the roil rate matches the pitch/yaw frequency. This phenomenon, called roll lock-in, results in an amplification of the trim angle, which can lead to yaw instability. A less severe phenomenon is that of transient resonance where the roll rate locks in at resonance briefly before continuing to build up to the design value. However, the trim amplification during the brief period of resona...

Ananthkrishnan, N.; Raisinghani, Sc; Pradeep, S.

1999-01-01

206

Modeling, simulation and identification for control of tandem cold metal rolling  

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: English Abstract in english This paper describes a modeling procedure for tandem cold metal rolling, including the linearization step and system identification for control. The tandem cold rolling process is described by a mathematical model based on algebraic equations developed for control purposes and empirical relations. A [...] state-space model is derived and detailed analyses in open loop are presented, concerning the sensitivity with regard to the variations in process parameters and results for the application of a new subspace identification method are compared with classical methodologies. Therefore, this work intents to be a contribution for developments in new control strategies for tandem cold rolling process that offer the potential to reduce the design efforts, the commissioning time and maintenance in rolling mills. The preliminary results obtained with this model have shown reasonable agreement with operational data presented at literature for industrial cold rolling process.

Péricles Guedes, Alves; José Adilson de, Castro; Luciano Pessanha, Moreira; Elder Moreira, Hemerly.

2012-12-01

207

Deformation and recrystallization textures in straight-rolled and pseudo cross-rolled AA 3105 aluminum alloy  

International Nuclear Information System (INIS)

The hot band of CC AA 3105 aluminum alloy was cold-rolled to different reductions along the original rolling and transverse directions, and then annealed at 427 oC for 24 h. The deformation and recrystallization textures in these cold-rolled sheets were investigated by X-ray diffraction. The result shows that further rolling of the hot band along the original rolling direction incrementally strengthens the ? fiber rolling texture. Under cross-rolling (i.e., along the original transverse direction), the former ? fiber orientations are unstable and they gradually rotate towards the ? fiber in the new sample reference system. The recrystallization is completed at a lower reduction in the cross-rolled specimens than in the straight-rolled specimens. The recrystallization texture of the straight-rolled specimens is characterized by the major P component and the minor R and Goss components. The recrystallization texture of the cross-rolled specimens depends on the cross-rolling reduction. As the cross-rolling reduction increases from 33% to 90%, the recrystallization texture is changed from the {0 1 2} texture through {1 11 7} to the P texture.

208

Austenitic steel rolling in the temperature range of anomalous ductility  

International Nuclear Information System (INIS)

Investigations are carried out on the strips of the Kh14G14N3T (EhI-711), OOOKh18N12 and Kh16N16M3B (EhI-847) steels, deformed, by shot rolling with summary reductions up to 80 % under conditions close to isothermal, at the temperatures in the range of 196-400 deg C as well as on the working cones of tube rolling of the 12Kh18N10T steel using the tube-cold-rolling mill at 20, 100, 200 and 300 deg C, their heating in the deformation focus has not been hindered. Dislocation structure and phase composition of the steels have been investigated using the methods of optical and electron microscopy, X-ray (in iron Ksub(?)-irradiation) and electron diffraction. It is shown that the effect of anomalous ductility during austenitic steel rolling is manifested in the temperature range being the lower the more stable austenit is in them and reaches the maximum at higher temperature than at stretching. The nature of anomalous ductility effect is complex and the essence of it is not only in stress relaxation in the process of phase transformations. Formation of stacking faults and transverse slipping, producing effect upon dislocation structure formation of austenite during rollling, plays a very importand role. Manifestation of the anomalous ductility effect depends on deformation heating an6 produces considerable effect upon formation of technological defects (cracks, fissures and so on) upon the treatment purity of the rolled surface of sheet and tubesheet and tubes

209

A method to determinate the thickness control parameters in cold rolling process through predictive model via neural networks  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The single stand rolling mill governing equation is a non-linear function on several parameters (input thickness, front and back tensions, yield stress and friction coefficient among others). Any alteration in one of them will cause alterations on the rolling load and, consequently, on the outgoing thickness. This paper presents a method to determinate the appropriate adjustment for thickness control considering three possible control parameters: roll gap, front and back tensions. The method ...

Za?rate, L. E.

2005-01-01

210

The Effects of Forming Parameters on Conical Ring Rolling Process  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The plastic penetration condition and biting-in condition of a radial conical ring rolling process with a closed die structure on the top and bottom of driven roll, simplified as RCRRCDS, were established. The reasonable value range of mandrel feed rate in rolling process was deduced. A coupled thermomechanical 3D FE model of RCRRCDS process was established. The changing laws of equivalent plastic strain (PEEQ) and temperature distributions with rolling time were investigated. The effects of ...

Wen Meng; Guoqun Zhao; Yanjin Guan

2014-01-01

211

Numerical and experimental analysis of lubrication in strip cold rolling  

Digital Repository Infrastructure Vision for European Research (DRIVER)

In this work an analytical model based on the slab method was built to analyze the lubrication during cold rolling of aluminum strips. Some process variables were studied like the rolling speed, the cross-section reduction, and lubricant viscosity. Numerical results are presented for pressure variation and film thickness at the inlet and work zones. The loads necessary to separate the rolls are also estimated. Some experimental results are shown for the surface roughness of the rolled product...

Sérgio Tonini Button

2011-01-01

212

Vibrations induced by surface roughness in nonlinear rolling contacts  

Digital Repository Infrastructure Vision for European Research (DRIVER)

For efficient transportation in either trains, busses or passenger cars, rolling elements such as wheels, tyres, bearings and transmission elements are fundamental. The energy efficiency and the generation of noise and vibrations in rolling contacts depend on the surface roughness of contacting bodies. In order to optimize the surfaces of rolling elements, prediction of its impact on the dynamic response from rolling excitation is required. A computationally efficient method to include surfac...

Lundberg, Oskar Erik

2014-01-01

213

Manifested flatness predictions in thin strip cold rolling  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The paper deals with flatness defects prediction in thin plates which appear during rolling. Their origin is the roll stack thermo-elastic deformation. The combination of the elastic deflection, the thermal crown and the roll grinding crown results in a non-parallel bite. If the transverse roll profile is not an affinity of the incoming strip profile, differential elongation results and induces high stresses in the outgoing strip. The latter combine with the imposed strip tension force, resul...

Abdelkhalek, Sami; Montmitonnet, Pierre; Legrand, Nicolas; Buessler, Pascal

2008-01-01

214

Flight test data for light aircraft spoiler roll control systems  

Science.gov (United States)

The results of flight tests to determine the characteristics of spoiler roll control systems on three different light aircraft are summarized. Comparisons are made with wind tunnel data where available. Flight tests indicate that excellent roll characteristics can be achieved with spoilers. Yaw coupling with roll control inputs is virtually eliminated. Roll rates remain high when flaps are deployed at low speed. Very mild nonlinearities in control effectiveness exist and there was no deadband or lag detected.

Kohlman, D. L.

1977-01-01

215

Oscillations and Rolling for Duffing's Equation  

Science.gov (United States)

The Duffing equation has been used to model nonlinear dynamics not only in mechanics and electronics but also in biology and in neurology for the brain process modeling. Van der Pol's method is often used in nonlinear dynamics to improve perturbation theory results when describing small oscillations. However, in some other problems of nonlinear dynamics particularly in case of Duffing-Higgs equation in field theory, for the Einsten-Friedmann equations in cosmology and for relaxation processes in neurology not only small oscillations regime is of interest but also the regime of slow rolling. In the present work a method for approximate solution to nonlinear dynamics equations in the rolling regime is developed. It is shown that in order to improve perturbation theory in the rolling regime it turns out to be effective to use an expansion in hyperbolic functions instead of trigonometric functions as it is done in van der Pol's method in case of small oscillations. In particular the Duffing equation in the rolling regime is investigated using solution expressed in terms of elliptic functions. Accuracy of obtained approximation is estimated. The Duffing equation with dissipation is also considered.

Aref'eva, I. Ya.; Piskovskiy, E. V.; Volovich, I. V.

2013-01-01

216

Grey Prediction on Rolling Bearing Friction Torque  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The rolling bearing friction torque is forecasted by means of the grey dynamic model GM (1, 1). Residual test and posteriori error test are conducted to verify the reliability of the results of prediction. The experiment shows that the method proposed has the high precision and satisfy the engineering demand.

Xintao Xia; Tao Ma

2012-01-01

217

Hot rolling of gamma titanium aluminide foil  

International Nuclear Information System (INIS)

Metal flow and microstructure evolution during the thermomechanical processing of thin-gage foil of a near-gamma titanium aluminide alloy, Ti-45.5Al-2Cr-2Nb, with an equiaxed-gamma microstructure was investigated experimentally and theoretically. Foils of thickness of 200-250 ?m were fabricated via hot rolling of sheet in a can of proprietary design. The variation in gage of the rolled foils was ±15 ?m except in very sporadic (local) areas, with variations of approximately 60 ?m relative to the mean. Metallography revealed that the larger thickness variations were associated with large remnant colonies lying in a hard orientation for deformation. To rationalize these observations, a self-consistent model was used to estimate the strain partitioning between the softer (equiaxed-gamma) matrix and the remnant colonies. Furthermore, the efficacy of pre- or post-rolling heat treatment in eliminating remnant colonies was demonstrated and quantified using a static-spheroidization model. The elimination of remnant colonies via spheroidization prior to foil rolling gave rise to improved gage control.

218

Hot rolling of gamma titanium aluminide foil  

Energy Technology Data Exchange (ETDEWEB)

Metal flow and microstructure evolution during the thermomechanical processing of thin-gage foil of a near-gamma titanium aluminide alloy, Ti-45.5Al-2Cr-2Nb, with an equiaxed-gamma microstructure was investigated experimentally and theoretically. Foils of thickness of 200-250 {mu}m were fabricated via hot rolling of sheet in a can of proprietary design. The variation in gage of the rolled foils was {+-}15 {mu}m except in very sporadic (local) areas, with variations of approximately 60 {mu}m relative to the mean. Metallography revealed that the larger thickness variations were associated with large remnant colonies lying in a hard orientation for deformation. To rationalize these observations, a self-consistent model was used to estimate the strain partitioning between the softer (equiaxed-gamma) matrix and the remnant colonies. Furthermore, the efficacy of pre- or post-rolling heat treatment in eliminating remnant colonies was demonstrated and quantified using a static-spheroidization model. The elimination of remnant colonies via spheroidization prior to foil rolling gave rise to improved gage control.

Semiatin, S.L., E-mail: lee.semiatin@wpafb.af.mil [Air Force Research Laboratory, Materials and Manufacturing Directorate, Wright-Patterson Air Force Base, OH 45433 (United States); Shanahan, B.W. [University of Dayton, 300 College Park, Dayton, OH 45409 (United States); Meisenkothen, F. [UES, Inc., 4401 Dayton-Xenia Road, Dayton, OH 45432 (United States)

2010-08-15

219

Cosmological constraints on rapid roll inflation  

International Nuclear Information System (INIS)

We obtain cosmological constraints on models of inflation which exhibit rapid roll solutions. Rapid roll attractors exist for potentials with large mass terms and are thus of interest for inflationary model building within string theory. We constrain a general ansatz for the power spectrum arising from rapid roll inflation that, in the small field limit, can be associated with tree level hybrid potentials with variable mass terms and nonminimal gravitational coupling ?R?2. We consider perturbations generated through modulated reheating and/or curvaton mechanisms in place of the observationally unacceptable primary spectra generated by inflaton fluctuations in these models. The lack of a hierarchy amongst higher-order k-dependencies of the power spectrum results in models with potentially large runnings, allowing us to impose tight constraints on such models using CMB and LSS data. In particular, we find ns < 1 and |?| < 0.01. We conclude with a concrete realization of rapid roll inflation within warped throat brane inflation that is in good agreement with current data

220

Texture changes in ?-zirconium on transverse rolling  

International Nuclear Information System (INIS)

The authors use x-ray diffraction to investigate the changes in texture in zirconium iodide and a zirconium-niobium alloy, two candidate cladding materials, which occur as a result of rolling the metals. Structural transformations are discussed in detail

 
 
 
 
221

Tunable swelling and rolling of microgel membranes.  

Science.gov (United States)

The tunable swelling and rolling of films assembled via layer-by-layer (LbL) methods from poly(N-isopropylacrylamide-co-acrylic acid) (pNIPAm-co-AAc) microgels and poly(ethylenimine) (PEI) have been systematically studied. Microgel/PEI films assembled at pH 7.4 display a high degree of in-plane swelling at low pH that dramatically increases the film area and drives self-delamination from the substrate to form a free-standing film. The degree of film swelling can be controlled by the size of microgels used in film fabrication. Taking advantage of this feature, self-rolled scrolls can be easily obtained from microgel/PEI films prepared from microgels of two different sizes. The rolling direction can be controlled by the assembly of different size microgels in different film strata, and the final shape of the scrolls can be controlled by scratching the desired film edges. The present work contributes to a deeper understanding of microgel/PEI film swelling properties and introduces a facile and novel method to prepare free-standing films and self-rolled scrolls. PMID:24927510

Zhang, Ling; Spears, Mark William; Lyon, L Andrew

2014-07-01

222

Cosmological rolling solutions of nonlocal theories  

Digital Repository Infrastructure Vision for European Research (DRIVER)

We find nonperturbative solutions of a nonlocal scalar field equation, with cubic or exponential potential on a cosmological background. The former case corresponds to the lowest level effective tachyon action of cubic string field theory. While the well known Minkowski solution is wildly oscillating, due to Hubble friction its cosmological counterpart describes smooth rolling towards the local minimum of the potential.

Calcagni, Gianluca; Nardelli, Giuseppe

2009-01-01

223

Vananemise ilu ehk restaureerimisarhitekti roll / Ove Hidemark  

Index Scriptorium Estoniae

Restaureerimisarhitekti ülesannetest - ta ei pea otsustama üksnes tehniliste küsimuste üle, vaid arvestama ka sajandite vältel muutunud maitset, vana käsitöö erilist atmosfääri, toetama ehitisse koondatud ajaloolist elamust, nähes selles aja ja muutumise tervikut ning inimkäe mõju ja ajaloo sünteesi. Artikkel "Att behärska åldrandets skönhet eller om restaureringsarkitektens roll" rootsi ajakirjast "Kulturmiljövård", 1990, nr.4, lk.13-16

Hidemark, Ove

1997-01-01

224

Rolling Friction on a Wheeled Laboratory Cart  

Science.gov (United States)

A simple model is developed that predicts the coefficient of rolling friction for an undriven laboratory cart on a track that is approximately independent of the mass loaded onto the cart and of the angle of inclination of the track. The model includes both deformation of the wheels/track and frictional torque at the axles/bearings. The concept of…

Mungan, Carl E.

2012-01-01

225

Har Det Etiske Råd udspillet sin rolle?  

DEFF Research Database (Denmark)

I anledning af diskussionen om Etisk Råds rolle omtales situationen ved dets oprettelse i 1988. Nye biomedicinske teknikker muliggjorde nye indgreb i det begyndende menneskeliv, som udfordrede tanken om menneskets værdighed. Den politiske regulering af teknikkerne fulgte en anden etisk linje. Derfor - og fordi betingelserne for den offentlige debat er drastisk ændret - kan man stille spørgsmål ved Etisk Råds nødvendighed.

Andersen, Svend

2014-01-01

226

46 CFR 28.575 - Severe wind and roll.  

Science.gov (United States)

...2010-10-01 2010-10-01 false Severe wind and roll. 28.575 Section 28.575...VESSELS Stability § 28.575 Severe wind and roll. (a) Each vessel must...this section when subjected to the gust wind heeling arm and the angle of roll to...

2010-10-01

227

25 CFR 75.4 - Basic membership roll.  

Science.gov (United States)

...2010-04-01 2010-04-01 false Basic membership roll. 75.4 Section 75.4 Indians... TRIBAL GOVERNMENT REVISION OF THE MEMBERSHIP ROLL OF THE EASTERN BAND OF CHEROKEE INDIANS, NORTH CAROLINA § 75.4 Basic membership roll. All persons whose names...

2010-04-01

228

Roll compaction and granulation system for nuclear fuel material  

International Nuclear Information System (INIS)

A roll compaction and roll granulation system has been designed and fabricated to replace conventional preslugging and crushing operations typically used in the fabrication of mixed oxide nuclear fuel pellets. This equipment will be of maintenance advantage with only the compaction and granulation rolls inside containment. The prototype is being tested and the results will be reported within a year

229

Development and Fabrication of Pineapple Rolled Tart Machine  

Directory of Open Access Journals (Sweden)

Full Text Available A pineapple rolled tart machine is required in the manufacturing of pineapple rolled tart. In this research, a machine that would reduce processing time and operating cost and that would be affordable for small-scale industries was designed. The machine was tested at different screw rotating speeds and dough formulations. The rolled tart throughput rates were significantly increased (p-1.

Azman Hamzah

2011-01-01

230

Conical Euler analysis and active roll suppression for unsteady vortical flows about rolling delta wings  

Science.gov (United States)

A conical Euler code was developed to study unsteady vortex-dominated flows about rolling, highly swept delta wings undergoing either forced motions or free-to-roll motions that include active roll suppression. The flow solver of the code involves a multistage, Runge-Kutta time-stepping scheme that uses a cell-centered, finite-volume, spatial discretization of the Euler equations on an unstructured grid of triangles. The code allows for the additional analysis of the free to-roll case by simultaneously integrating in time the rigid-body equation of motion with the governing flow equations. Results are presented for a delta wing with a 75 deg swept, sharp leading edge at a free-stream Mach number of 1.2 and at 10 deg, 20 deg, and 30 deg angle of attack alpha. At the lower angles of attack (10 and 20 deg), forced-harmonic analyses indicate that the rolling-moment coefficients provide a positive damping, which is verified by free-to-roll calculations. In contrast, at the higher angle of attack (30 deg), a forced-harmonic analysis indicates that the rolling-moment coefficient provides negative damping at the small roll amplitudes. A free-to-roll calculation for this case produces an initially divergent response, but as the amplitude of motion grows with time, the response transitions to a wing-rock type of limit cycle oscillation, which is characteristic of highly swept delta wings. This limit cycle oscillation may be actively suppressed through the use of a rate-feedback control law and antisymmetrically deflected leading-edge flaps. Descriptions of the conical Euler flow solver and the free-to roll analysis are included in this report. Results are presented that demonstrate how the systematic analysis of the forced response of the delta wing can be used to predict the stable, neutrally stable, and unstable free response of the delta wing. These results also give insight into the flow physics associated with unsteady vortical flows about delta wings undergoing forced motions and free-to-roll motions, including the active suppression of the wing-rock type phenomenon. The conical Euler methodology developed is directly extend able to three-dimensional calculations.

Lee-Rausch, Elizabeth M.; Batina, John T.

1993-01-01

231

75 FR 16504 - Hot-Rolled Flat-Rolled Carbon-Quality Steel Products From Brazil, Japan, and Russia  

Science.gov (United States)

...Steel Products From Brazil, Japan, and Russia AGENCY: United States International Trade...investigation on hot-rolled steel from Russia...investigation on hot-rolled steel from Russia would be likely to lead to...

2010-04-01

232

75 FR 62566 - Hot-Rolled Flat-Rolled Carbon-Quality Steel Products From Brazil, Japan, and Russia  

Science.gov (United States)

...Steel Products From Brazil, Japan, and Russia AGENCY: United States International Trade...investigation on hot-rolled steel from Russia...investigation on hot-rolled steel from Russia would be likely to lead to...

2010-10-12

233

75 FR 42782 - Hot-Rolled Flat-Rolled Carbon-Quality Steel Products From Brazil, Japan, and Russia  

Science.gov (United States)

...Steel Products From Brazil, Japan, and Russia AGENCY: United States International Trade...investigation on hot-rolled steel from Russia...investigation on hot-rolled steel from Russia would be likely to lead to...

2010-07-22

234

Towards Realizing High-Throughput, Roll-to-Roll Manufacturing of Flexible Electronic Systems  

Digital Repository Infrastructure Vision for European Research (DRIVER)

High-rate roll-to-roll (R2R) tracker systems are utilized for large volume flexible electronic device manufacturing, and the current alignment mechanism between layers is mainly achieved by relying on passive techniques. In this paper, we present a machine vision based alignment strategy that is used to achieve precise registration for stacking multilayers. Based on this strategy, we demonstrate two-layer printing with alignment accuracy better than 100 ?m in web moving direction and 200 ?m...

Xiaohui Lin; Harish Subbaraman; Zeyu Pan; Amir Hosseini; Chris Longe; Klay Kubena; Paul Schleicher; Phillip Foster; Sean Brickey; Chen, Ray T.

2014-01-01

235

High-rate, roll-to-roll nanomanufacturing of flexible systems  

Science.gov (United States)

Since the National Nanotechnology Initiative was first announced in 2000, nanotechnology has developed an impressive catalog of nano-scale structures with building-blocks such as nanoparticles, nanotubes, nanorods, nanopillars, and quantum dots. Similarly, there are accompanying materials processes such as, atomic layer deposition, pulsed layer deposition, nanoprinting, nanoimprinting, transfer printing, nanolithography and nanopatterning. One of the challenges of nanomanufacturing is scaling up these processes reliably and affordably. Roll-to-roll manufacturing is a means for scaling up, for increasing throughput. It is high-speed production using a continuous, moving platform such as a web or a flexible substrate. The adoption of roll-to-roll to nanomanufacturing is novel. The goal is to build structures and devices with nano-scale features and specific functionality. The substrate could be a polymer, metal foil, silk, cloth or paper. The materials to build the structures and multi-level devices could be organic, inorganic or biological. Processing could be solution-based, e.g., ink-jet printing, or vacuum-based, e.g., chemical vapor deposition. Products could be electronics, optoelectronics, membranes, catalysts, microfluidics, lab-on-film, filters, etc. By this means, processing of large and conformal areas is achievable. High-throughput translates into low cost, which is the attraction of roll-to-roll nanomanufacturing. There are technical challenges requiring fundamental scientific advances in materials and process development and in manufacturing and system-integration where achieving nano-scale feature size, resolution and accuracy at high speeds can be major hurdles. We will give an overview of roll-to-roll nanomanufacturing with emphasis on the need to understand the material, process and system complexities, the need for instrumentation, measurement, and process control and describe the concept of cyber-enabled nanomanufacturing for reliable and predictable production.

Cooper, Khershed P.; Wachter, Ralph F.

2012-10-01

236

Continuous roll-to-roll growth of graphene films by chemical vapor deposition  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Few-layer graphene is obtained in atmospheric chemical vapor deposition on polycrystalline copper in a roll-to-roll process. Raman and x-ray photoelectron spectroscopy were employed to confirm the few-layer nature of the graphene film, to map the inhomogeneities, and to study and optimize the growth process. This continuous growth process can be easily scaled up and enables the low-cost fabrication of graphene films for industrial applications. © 2011 American Institute of Physics.

Hesjedal, T.

2011-01-01

237

Patterned Immobilization of Antibodies within Roll-to-Roll Hot Embossed Polymeric Microfluidic Channels  

Digital Repository Infrastructure Vision for European Research (DRIVER)

This paper describes a method for the patterned immobilization of capture antibodies into a microfluidic platform fabricated by roll-to-roll (R2R) hot embossing on poly (methyl methacrylate) (PMMA). Covalent attachment of antibodies was achieved by two sequential inkjet printing steps. First, a polyethyleneimine (PEI) layer was deposited onto oxygen plasma activated PMMA foil and further cross-linked with glutaraldehyde (GA) to provide an amine-reactive aldehyde surface (PEI-GA). This step wa...

Feyssa, Belachew; Liedert, Christina; Kivimaki, Liisa; Johansson, Leena-sisko; Jantunen, Heli; Hakalahti, Leena

2013-01-01

238

Micro-Plasto-Hydrodynamic Lubrication a Fundamental Mechanism in Cold Rolling  

DEFF Research Database (Denmark)

This paper presents recent investigations in Micro-Plasto-Hydrodynamic (MPH) lubrication. Industrial evidences of the existence of MPH lubrication mechanism for cold rolling processes are presented. A new lubrication model developed for strip drawing processes is then applied to predict the MPH lubrication initiation and MPH lubrication extension along the tool-piece solid contacts initially in boundary lubrication regime. Finally, it is shown how this new MPH lubrication model can be implemented in a cold rolling model to maximize mills capabilities, determine optimum rolling oils properties and predict roughness transfer.

Laugier, Maxime; Boman, Romain

2014-01-01

239

High resolution patterning for flexible electronics via roll-to-roll nanoimprint lithography  

Science.gov (United States)

Flexible electronics is a growing field and is currently maturing in applications such as displays, smart packaging, organic light-emitting diodes and organic photovoltaic cells. In order to process on flexible substrates at high throughput and large areas, novel patterning techniques will be essential. Conventional optical lithography is limited in throughput as well as resolution, and requires several alignment steps to generate multi-layered patterns, required for applications such as thin-film transistors. It therefore remains a complex and expensive process. Nanoimprint lithography is an emerging alternative to optical lithography, demonstrating patterning capabilities over a wide range of resolutions, from several microns down to a few nanometres. For display applications, nanoimprint lithography can be used to pattern various layers. Micron sized thin-film transistors for backplane can be fabricated where a self-aligned geometry is used to decrease the number of alignment steps, and increase the overlay accuracy. In addition, nano-structures can be used for optical applications such as anti-reflective surfaces and nano patterned transparent electrodes. Imprint lithography is a fully roll-to-roll compatible process and enables large area and high throughput fabrication for flexible electronics. In this paper we discuss the possibilities and the challenges of large area patterning by roll-to-roll nanoimprint lithography, reviewing micron and nano sized structures realized on our roll-to-roll equipment. Nano patterned transparent electrodes, moth-eye antireflective coatings, and multilevel structures will be covered.

Sabik, Sami; de Riet, Joris; Yakimets, Iryna; Smits, Edsger

2014-03-01

240

Producton method of hot-rolled sheets and plates of titanium alloys with intermittent rolling process  

International Nuclear Information System (INIS)

A new method is proposed for the production of hot-rolled sheets and plates from titanium alloys involving interruption of the rolling process. The method makes it possible to improve the mechanical properties of rolled iron sheets. To improve the microstructure of sheets consisting of ?-and (2? + 2?)-alloys the hot and warm rolling processes are combined with into one by cooling the stock followed by deformation according to conditions of the warm rolling process. A method is proposed involving two heating cycles followed by cooling to room temperature and then by heating the strip to the temperature corresponding to (?+?)-phase and rolling the metal to the required dimensions with the degree of shingling being not less 40%. A comparative metallographic analysis has shown that the microstructure of sheets of different thickness is characterized by the absence of streaks of well defined boundaries of ?-grains and by the presence of uniformly dispersed mixture of (?+ ?)-phase. The relative elongation has grown from 2 -10% to 6 - 12% with some increase in the strength of the metal. The developed method is recommended for the production of plates and thick sheets from various titanium alloys

 
 
 
 
241

Metal flowing of involute spline cold roll-beating forming  

Science.gov (United States)

The present research on involute spline cold roll-beating forming is mainly about the principles and motion relations of cold roll-beating, the theory of roller design, and the stress and strain field analysis of cold roll-beating, etc. However, the research on law of metal flow in the forming process of involute spline cold roll-beating is rare. According to the principle of involute spline cold roll-beating, the contact model between the rollers and the spline shaft blank in the process of cold roll-beating forming is established, and the theoretical analysis of metal flow in the cold roll-beating deforming region is proceeded. A finite element model of the spline cold roll-beating process is established, the formation mechanism of the involute spline tooth profile in cold roll-beating forming process is studied, and the node flow tracks of the deformation area are analyzed. The experimental research on the metal flow of cold roll-beating spline is conducted, and the metallographic structure variation, grain characteristics and metal flow line of the different tooth profile area are analyzed. The experimental results show that the particle flow directions of the deformable bodies in cold roll-beating deformation area are determined by the minimum moving resistance. There are five types of metal flow rules of the deforming region in the process of cold roll-beating forming. The characteristics of involute spline cold roll-beating forming are given, and the forming mechanism of involute spline cold roll-beating is revealed. This paper researches the law of metal flow in the forming process of involute spline cold roll-beating, which provides theoretical supports for solving the tooth profile forming quality problem.

Cui, Fengkui; Wang, Xiaoqiang; Zhang, Fengshou; Xu, Hongyu; Quan, Jianhui; Li, Yan

2013-09-01

242

Roll caster for the three-layer clad-strip  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Purpose: of this paper is to show the characteristics of two kinds of roll casters for three-layer clad strip of aluminium alloys. Moreover, the characteristics of these twin roll casters were compeered with the early type of roll casters for clad strip.Design/methodology/approach: Design was tried to attain the fabrication of the roll casters to cast the three-layers-clad-strip. One caster was an unequal diameter roll caster equipped with a scraper. The scraper was adopted to prevent the mix...

Nakamura, R.; Yamabayashi, T.; Haga, T.; Kumai, S.; Watari, H.

2010-01-01

243

Densification behavior of titanium in direct powder rolling process  

International Nuclear Information System (INIS)

The densification behavior of titanium powder in the direct powder rolling process was investigated. An analytical model for the roll backlash phenomenon during this process was proposed to conduct a realistic finite element analysis. Furthermore, the roll backlash was quantitatively analyzed, and the relative densities of the green strip along the rolling direction were precisely estimated. Finally, the slip and nip phenomena were identified by calculating the contact pressure and shear stress between the titanium powder and the roller in order to understand the densification behavior of the powder during the rolling process

244

Static measurements of slender delta wing rolling moment hysteresis  

Science.gov (United States)

Slender delta wing planforms are susceptible to self-induced roll oscillations due to aerodynamic hysteresis during the limit cycle roll oscillation. Test results are presented which clearly establish that the static rolling moment hysteresis has a damping character; hysteresis tends to be greater when, due to either wing roll or side slip, the vortex burst moves back and forth over the wing trailing edge. These data are an indirect indication of the damping role of the vortex burst during limit cycle roll oscillations.

Katz, Joseph; Levin, Daniel

1991-01-01

245

Toward large-area roll-to-roll printed nanophotonic sensors  

Science.gov (United States)

Polymers have become an important material group in fabricating discrete photonic components and integrated optical devices. This is due to their good properties: high optical transmittance, versatile processability at relative low temperatures and potential for low-cost production. Recently, nanoimprinting or nanoimprint lithography (NIL) has obtained a plenty of research interest. In NIL, a mould is pressed against a substrate coated with a moldable material. After deformation of the material, the mold is separated and a replica of the mold is formed. Compared with conventional lithographic methods, imprinting is simple to carry out, requires less-complicated equipment and can provide high-resolution with high throughput. Nanoimprint lithography has shown potential to become a method for low-cost and high-throughput fabrication of nanostructures. We show the development process of nano-structured, large-area multi-parameter sensors using Photonic Crystal (PC) and Surface Enhanced Raman Scattering (SERS) methodologies for environmental and pharmaceutical applications. We address these challenges by developing roll-to-roll (R2R) UV-nanoimprint fabrication methods. Our development steps are the following: Firstly, the proof of concept structures are fabricated by the use of wafer-level processes in Si-based materials. Secondly, the master molds of successful designs are fabricated, and they are used to transfer the nanophotonic structures into polymer materials using sheet-level UV-nanoimprinting. Thirdly, the sheet-level nanoimprinting processes are transferred to roll-to-roll fabrication. In order to enhance roll-to-roll manufacturing capabilities, silicone-based polymer material development was carried out. In the different development phases, Photonic Crystal and SERS sensor structures with increasing complexities were fabricated using polymer materials in order to enhance sheet-level and roll-to-roll manufacturing processes. In addition, chemical and molecular imprint (MIP) functionalization methods were applied in the sensor demonstrators. In this paper, the process flow in fabricating large-area nanophotonic structures by the use of sheet-level and roll-to-roll UV- nanoimprinting is reported.

Karioja, Pentti; Hiltunen, Jussi; Aikio, Sanna M.; Alajoki, Teemu; Tuominen, Jarkko; Hiltunen, Marianne; Siitonen, Samuli; Kontturi, Ville; Böhlen, Karl; Hauser, Rene; Charlton, Martin; Boersma, Arjen; Lieberzeit, Peter; Felder, Thorsten; Eustace, David; Haskal, Eliav

2014-05-01

246

Control of missile dispersion via roll rate modulation  

Science.gov (United States)

Feedback control via roll rate modulation to limit cross-range dispersion of spinning missiles is investigated. The dispersion to be controlled is assumed to result from lift variations that do not average out over a roll cycle when the missile roll rate remains constant. By modulating the roll rate in a prescribed manner through feedback control, lift nonaveraging and the resulting cross-range dispersion are minimized. Two different approaches to the feedback control are investigated. In one approach, the roll rate is modulated by feedback of the state variables to prevent the occurrence of lateral velocity increments that produce dispersion. In the other approach, the roll rate is modulated harmonically about a steady roll rate, and the amplitude of the harmonic variation is controlled to limit dispersion.

Platus, D. H.; Shandling, J.

1985-11-01

247

ROLLING PROCESS WITH OHSAS AND TEXTURE FORMATION– A REVIEW  

Directory of Open Access Journals (Sweden)

Full Text Available Rolling is a mechanical treatment, which plays an important part in the processing of ferrous and nonferrous alloys. Texturing is an important phenomenon that occurs after rolling process. Preferred orientation increases the strength of the material enormously. Hence the research is focused on the rolling studies and the texture formation, which occurs after rolling process. This review mainly focuses on rolling process carried out in different alloys. It also highlights the analysis made on various rolling parameters for improving the mechanical properties. Texture studies carried on various ferrous and non-ferrous alloys; particularly in nitrogen alloyed duplex stainless steel is discussed. Finally the need for implementation of occupational health and safety during a thermomechanical treatment is also discussed. The state of art in this field is encouraging and showing positive signs of commercializing rolled nitrogen alloyed duplex stainless steel after proper texture control.

P. CHANDRAMOHAN

2009-03-01

248

Investigations upon the indefinite rolls quality assurance in multiple regression analysis  

International Nuclear Information System (INIS)

The rolling rolls quality has been enhanced mainly due to the improvements of the chemical compositions of rolls materials. The realization of an optimal chemical composition can constitute a technical efficient mode to assure the exploitation properties, the material from which the rolling mills rolls are manufactured having a higher importance in this sense. This paper continues to present the scientifically results of our experimental research in the area of the rolling rolls. The basic research contains concrete elements of immediate practical utilities in the metallurgical enterprises, for the quality improvements of rolls, having in last as the aim the durability growth and the safety in exploitation. This paper presents an analysis of the chemical composition, the influences upon the mechanical properties of the indefinite cast iron rolls. We present some mathematical correlations and graphical interpretations between the hardness (on the working surface and on necks) and the chemical composition. Using the double and triple correlations which is really helpful in the foundry practice, as it allows us to determine variation boundaries for the chemical composition, in view the obtaining the optimal values of the hardness. We suggest a mathematical interpretation of the influence of the chemical composition over the hardness of these indefinite rolling rolls. In this sense we use the multiple regression analysis which can be an important statistical tool for the be an important statistical tool for the investigation of relationships between variables. The enunciation of some mathematically modeling results can be described through a number of multi-component equations determined for the spaces with 3 and 4 dimensions. Also, the regression surfaces, curves of levels and volumes of variations can be represented and interpreted by technologists considering these as correlation diagrams between the analyzed variables. In this sense, these researches results can be used in the engineers collectives of the foundries and the rolling mills sectors, for quality assurances of rolls as far back as phase of production, as well as in exploitation of these, what lead to, inevitably, to the quality assurance of produced laminates. (Author) 16 refs.

249

Calculation and Analysis of Temperature Distribution in Hot Rolling Strip  

Directory of Open Access Journals (Sweden)

Full Text Available Modern steel grades require constant and reproducible production conditions both in the hot strip mill and in the cooling section to achieve constant material properties along the entire strip length and from strip to strip. Calculation of the temperature in final rolling process always utilizes factors such as the work piece's inner organizational structure, plastic deformation, and it's variations of properties and so on, also as well as the physical parameters such as gauge, shape, etc. In this paper, a finite element model is constructed for the temperature field in a rolling process. The temperature field of strip steel is modeled with a 3-D finite element analysis (FEA structure, simultaneously considering the distribution of the work roll temperature. Then the distribution of field is simulated numerically. From the model, the temperature contours can be obtained by analysis of the temperature distribution of contact area. At the same time, the distribution of temperature in any position at any time can be acquired. These efforts provide the reliable parameters for the later finishing temperature and shape control.  

Kaixiang Peng

2013-07-01

250

Contact conditions in skin-pass rolling  

DEFF Research Database (Denmark)

The special contact conditions in skin-pass rolling of steel strip is analysed by studying plane strain upsetting of thin sheet with low reduction applying long narrow tools and dry friction conditions. An extended sticking region is estimated by an elasto-plastic FEM analysis of the plane strain upsetting. This sticking region causes a highly inhomogeneous elasto-plastic deformation with large influence of work-hardening and friction. A numerical analysis of skin-pass rolling shows the same contact conditions, i.e. an extended sticking region around the center of the contact zone. The calculated size of the sticking region with varying contact length and pressure/reduction is experimentally verified by plane strain upsetting tests measuring the local surface deformation of the work pieces after unloading.

Kijima, Hideo; Bay, Niels

2007-01-01

251

Void formation during beryllium hot rolling  

International Nuclear Information System (INIS)

A study has been made of the causes for brittle destruction of beryllium strips in the course of hot rolling (700-850 deg C) by investigating the dislocation structure. The distribution of dislocations in the body of the specimen was determined by the pickling pit method. It has been pointed out that with low drafting the highest density of dislocation is observed in the near contact layers close to the cold rolls. The accumulation of dislocations with further deformation form pores that are further combined in chains facilitating the origination of cracks. The fluctuation of the crack near the horizontal and vertical axes of symmetry of the specimen in the course of its propagation gives reason to believe that there is an area of tensile stresses in the middle of the strip when the metal comes out of the deformation nucleus

252

Rapid roll Inflation with Conformal Coupling  

CERN Document Server

Usual inflation is realized with a slow rolling scalar field minimally coupled to gravity. In contrast, we consider dynamics of a scalar with a flat effective potential, conformally coupled to gravity. Surprisingly, it contains an attractor inflationary solution with the rapidly rolling inflaton field. We discuss models with the conformal inflaton with a flat potential (including hybrid inflation). There is no generation of cosmological fluctuations from the conformally coupled inflaton. We consider realizations of modulated (inhomogeneous reheating) or curvaton cosmological fluctuations in these models. We also implement these unusual features for the popular string-theoretic warped inflationary scenario, based on the interacting D3-antiD3 branes. The original warped brane inflation suffers a large inflaton mass due to conformal coupling to 4-dimensional gravity. Instead of considering this as a problem and trying to cure it with extra engineering, we show that warped inflation with the conformally coupled, ...

Kofman, Lev

2007-01-01

253

The Winchester pipe rolls and their historians.  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The Winchester pipe rolls - the estate accounts of the bishops of Winchester - constitute one of the most remarkable documentary survivals from medieval England, and are without parallel anywhere in the world, supplying detailed evidence for agriculture, prices, wages, the land market and peasant society in an exceptionally well-preserved sequence from 1209 onwards. They have attracted the attention of historians of medieval economy and society for over a century, first in deposit in the Publ...

Britnell, R. H.

2003-01-01

254

A Model of Active Roll Vehicle Suspension  

Digital Repository Infrastructure Vision for European Research (DRIVER)

This paper describes active suspension with active roll for four-wheel vehicle (bus) by means of an in-series pump actuator with doubled hydropneumatic springs. It also gives full control law with no sky-craping. Lateral stiffness and solid axle geometry in the mechanical model are not neglected. Responses to lateral input as well as responses to statistical unevennesses show considerable improvement of passengers comfort and safety when cornering.

C?ech, I.

2010-01-01

255

Weak Rolling Adhesion Enhances Bacterial Surface Colonization? †  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Bacterial adhesion to and subsequent colonization of surfaces are the first steps toward forming biofilms, which are a major concern for implanted medical devices and in many diseases. It has generally been assumed that strong irreversible adhesion is a necessary step for biofilm formation. However, some bacteria, such as Escherichia coli when binding to mannosylated surfaces via the adhesive protein FimH, adhere weakly in a mode that allows them to roll across the surface. Since single-point...

Anderson, Brett N.; Ding, Albert M.; Nilsson, Lina M.; Kusuma, Kaoru; Tchesnokova, Veronika; Vogel, Viola; Sokurenko, Evgeni V.; Thomas, Wendy E.

2006-01-01

256

Rolling circle amplification of metazoan mitochondrialgenomes  

Energy Technology Data Exchange (ETDEWEB)

Here we report the successful use of rolling circle amplification (RCA) for the amplification of complete metazoan mt genomes to make a product that is amenable to high-throughput genome sequencing techniques. The benefits of RCA over PCR are many and with further development and refinement of RCA, the sequencing of organellar genomics will require far less time and effort than current long PCR approaches.

Simison, W. Brian; Lindberg, D.R.; Boore, J.L.

2005-07-31

257

Roll up nanowire battery from silicon chips  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Here we report an approach to roll out Li-ion battery components from silicon chips by a continuous and repeatable etch-infiltrate-peel cycle. Vertically aligned silicon nanowires etched from recycled silicon wafers are captured in a polymer matrix that operates as Li+ gel-electrolyte and electrode separator and peeled off to make multiple battery devices out of a single wafer. Porous, electrically interconnected copper nanoshells are conformally deposited around the silicon nanowires to stab...

Vlad, Alexandru; Reddy, Arava Leela Mohana; Ajayan, Anakha; Singh, Neelam; Gohy, Jean-franc?ois; Melinte, Sorin; Ajayan, Pulickel M.

2012-01-01

258

Boundary friction on molecular lubricants: rolling mode?  

International Nuclear Information System (INIS)

A theoretical model is proposed for low-temperature friction between two smooth rigid solid surfaces separated by lubricant molecules, admitting their deformations and rotations. The appearance of different modes of energy dissipation (by 'rocking' or 'rolling' of lubricants) at slow relative displacement of the surfaces is shown to be accompanied by stick-and-slip features and reveals a nonmonotonic (mean) friction force vs external load

259

Communication using eye roll reflective signalling  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Body reflections in the ultraviolet (UV) are a common occurrence in nature. Despite the abundance of such signals and the presence of UV cones in the retinas of many vertebrates, the function of UV cones in the majority of taxa remains unclear. Here, we report on an unusual communication system in the razorback sucker, Xyrauchen texanus, that involves flash signals produced by quick eye rolls. Behavioural experiments and field observations indicate that this form of communication is used to s...

Novales Flamarique, I.; Mueller, G. A.; Cheng, C. L.; Figiel, C. R.

2007-01-01

260

A model for rolling swarms of locusts  

Digital Repository Infrastructure Vision for European Research (DRIVER)

We construct an individual-based kinematic model of rolling migratory locust swarms. The model incorporates social interactions, gravity, wind, and the effect of the impenetrable boundary formed by the ground. We study the model using numerical simulations and tools from statistical mechanics, namely the notion of H-stability. For a free-space swarm (no wind and gravity), as the number of locusts increases, it approaches a crystalline lattice of fixed density if it is H-stab...

Topaz, Chad M.; Bernoff, Andrew J.; Logan, Sheldon; Toolson, Wyatt

2007-01-01

 
 
 
 
261

Modeling of Rolling Knee Biped Robot  

Digital Repository Infrastructure Vision for European Research (DRIVER)

This report presents the dynamic modeling of a planar biped robot. The robot has seven bodies and 9 DOF. Two kinematic configurations are investigated. The first has only revolute joints on all articulation. The second differs by the presence of rolling contact on the knees. All matrices involved in the model are given in explicit form. All the possibilities of contact between the feet and the ground are considered.

Hobon, Mathieu; Lakbakbi Elyaaqoubi, Nafissa; Abba, Gabriel

2013-01-01

262

Optimization Design of the Die of Synchronization Rolling Axle on Cross-Wedge Rolling with Multi-Wedge  

Science.gov (United States)

For the rolling axle on Cross-Wedge Rolling with Multi-wedge, the key question is to guarantee the even distortion on each spot of the rolled pieces. In this paper, it has been taken that technological parameters of various wedges and the order of the rolling task completed by the third wedge as the design variable, the final rolled piece of the far even distortion as the research aim. By using method combined with the optimization design and the finite element method, the multi-wedge die of railway axle has been designed, in the meantime, its experimental verification has been given. The findings presents the rationale to realize the economization and the highly effective production on synchronization rolled axle of Cross-Wedge Rolling with Multi-wedge.

Xue dao, Shu; Chuan min, Li; Zheng huan, Hu

2010-06-01

263

Influence of Surge on Extreme Roll Amplitudes  

DEFF Research Database (Denmark)

Interference of the wave-induced ship surge motion with roll dynamics has been studied. The surge motion has been included in a previously derived hydrodynamic roll prediction model in order to account for the ship speed variation due to the longitudinal incident wave pressure force. Depending on the position of the wave crest relatively to the ship, the ship will be slowed down when she meets the wave. In this paper attempts are made to accurately account for added resistance and additional thrust, applied in order to maintain the ship speed. The surge equilibrium equation has been longitudinally balanced in order to determine the added thrust term that would represent actions to maintain speed The resulting forward speed variation affects the frequency of encounter and the parametric roll resonant condition is directly influenced by this speed variation. The analysis procedure is demonstrated for an example containership sailing mainly in head sea condition and higher sea states. Sensitivity of the results to the added thrust model and vertical motion calculation is discussed.

Vidic-Perunovic, Jelena; Rognebakke, Olav

2008-01-01

264

Arrested coarsening of granular roll waves  

Science.gov (United States)

We study a system in which granular matter, flowing down an inclined chute with periodic boundary conditions, organizes itself in a train of roll waves of varying size. Since large waves travel faster than small ones, the waves merge, and their number gradually diminishes. This coarsening process, however, does not generally proceed to the ultimate one-wave state: Numerical simulations of the dynamical equations (being the granular analogue of the shallow water equations) reveal that the process is arrested at some intermediate stage. This is confirmed by a theoretical analysis, in which we show that the roll waves cannot grow beyond a certain limiting size (which is fully determined by the system parameters), meaning that on long chutes the material necessarily remains distributed over more waves. We determine the average lifetime ?N of the successive N-wave states, from the initial state with typically N = 50 waves (depending on the length of the periodic domain) down to the final state consisting of only a handful of waves (N = Narr). At the latter value of N, the lifetime ?N goes to infinity. At this point the roll waves all have become equal in size and are traveling with the same speed. Our theoretical predictions for the successive lifetimes ?N and the value for Narr show good agreement with the numerical observations.

Razis, D.; Edwards, A. N.; Gray, J. M. N. T.; van der Weele, Ko

2014-12-01

265

Compaction Behavior of Isomalt after Roll Compaction  

Directory of Open Access Journals (Sweden)

Full Text Available The suitability of the new isomalt grade galenIQ™ 801 for dry granulation and following tableting is evaluated in this study. Isomalt alone, as well as a blend of equal parts with dibasic calcium phosphate, is roll compacted and tableted. Particle size distribution and flowability of the granules and friability and disintegration time of the tablets are determined. Tensile strength of tablets is related to the specific compaction force during roll compaction and the tableting force. In all cases, the tensile strength increases with raising tableting forces. The specific compaction force has a different influence. For isomalt alone the tensile strength is highest for tablets made from granules prepared at 2 kN/cm and 6 kN/cm and decreases at higher values, i.e., >10 kN/cm. Tensile strength of the blend tablets is almost one third lower compared to the strongest tablets of pure isomalt. Friability of pure isomalt tablets is above the limit. Disintegration time is longest when the tensile strength is at its maximum and decreases with higher porosity and lower tensile strengths. Isomalt proves to be suitable for tableting after roll compaction. Even though the capacity as a binder might not be as high as of other excipients, it is a further alternative for the formulation scientist.

Peter Kleinebudde

2012-09-01

266

Compaction behavior of isomalt after roll compaction.  

Science.gov (United States)

The suitability of the new isomalt grade galenIQ™ 801 for dry granulation and following tableting is evaluated in this study. Isomalt alone, as well as a blend of equal parts with dibasic calcium phosphate, is roll compacted and tableted. Particle size distribution and flowability of the granules and friability and disintegration time of the tablets are determined. Tensile strength of tablets is related to the specific compaction force during roll compaction and the tableting force. In all cases, the tensile strength increases with raising tableting forces. The specific compaction force has a different influence. For isomalt alone the tensile strength is highest for tablets made from granules prepared at 2 kN/cm and 6 kN/cm and decreases at higher values, i.e., >10 kN/cm. Tensile strength of the blend tablets is almost one third lower compared to the strongest tablets of pure isomalt. Friability of pure isomalt tablets is above the limit. Disintegration time is longest when the tensile strength is at its maximum and decreases with higher porosity and lower tensile strengths. Isomalt proves to be suitable for tableting after roll compaction. Even though the capacity as a binder might not be as high as of other excipients, it is a further alternative for the formulation scientist. PMID:24300366

Quodbach, Julian; Mosig, Johanna; Kleinebudde, Peter

2012-01-01

267

Development and investigation of industrial technique for hot rolling of small cross section rods of unyielding heat resisting alloys  

International Nuclear Information System (INIS)

A hot-rolling technology has been developed for rolling rods about 14 to 16 mm in diameter made of EI826, EI929VD, EI867VD heat-resistant nickel alloys, the rods being used for manufacturing the fastening parts and for die-forging blades. The blanks preheated up to a temperature of 1160 to 1190 deg C are rolled on ''300/450'' rolling mill in two processes according to two roll pass designs; namely, oval-round for rolling the rods 16 mm in diameter, and square-oval-round for the rods 14 mm in diameter. It is the installation of the technology of manufacturing rods of decreased diameters from the above heat-resistant alloys that yields a considerable economical effect, owing to the saving of up to 40% of an expensive metal and to the reducing of the amount of work as required for manufacturing the machine parts

268

Rolling friction—models and experiment. An undergraduate student project  

Science.gov (United States)

In this paper the rolling friction (rolling resistance) model is studied theoretically and experimentally in undergraduate level fundamental general physics courses. Rolling motions of a cylinder along horizontal or inclined planes are studied by simple experiments, measuring deformations of the underlay or of the rolling body. The rolling of a hard cylinder on a soft underlay as well as of a soft cylinder on a hard underlay is studied. The experimental data are treated by the open source software Tracker, appropriate for use at the undergraduate level of physics. Interpretation of results is based on elementary considerations comprehensible to university students—beginners. It appears that the commonly accepted model of rolling resistance based on the idea of a warp (little bulge) on the underlay in front of the rolling body does not correspond with experimental results even for the soft underlay and hard rolling body. The alternative model of the rolling resistance is suggested in agreement with experiment and the corresponding concept of the rolling resistance coefficient is presented. In addition to the obtained results we can conclude that the project can be used as a task for students in practical exercises of fundamental general physics undergraduate courses. Projects of similar type effectively contribute to the development of the physical thinking of students.

Vozdecký, L.; Bartoš, J.; Musilová, J.

2014-09-01

269

Troll, a Language for specifying Dice-rolls  

DEFF Research Database (Denmark)

Dice are used in many games, and often in fairly complex ways that make it difficult to unambiguously describe the dice-roll mechanism in plain language. Many role-playing games, such as Dungeons & Dragons, use a formalised notation for some instances of dice-rolls. This notation, once explained, make dice-roll descriptions concise and unambiguous. Furthermore, the notation has been used in automated tools for pseudo-random dice-rolling (typically used when playing over the Internet). This notation is, however, fairly limited in the types of dice-rolls it can describe, so most games still use natural language to describe rolls. Even Dungeons & Dragons use formal notation only for some of the dice-roll methods used in the game. Hence, a more complete notation is in this paper proposed, and a tool for pseudo-random rolls and (nearly) exact probability calculations is described. The notation is called "Troll", combining the initial of the Danish word for dice ("terninger") with the English word "roll". It is a development of the language Roll described in an earlier paper. The present paper describes the most important features of Troll and its implementation.

Mogensen, Torben Ægidius

2009-01-01

270

High Strength and Ductility of Ultrathin Laminate Foils Using Accumulative Roll Bonding and Asymmetric Rolling  

Science.gov (United States)

As product miniaturization is becoming widely popular, many microparts are being produced by microforming of sheets/foils, whose strength needs to be able to maintain structural stability of the micro-components. In addition, their strength and ductility of foils generally reduce with a reduction in the thickness due to the size effect. In this paper, we report the fabrication of an aluminum laminate foil using a combined process of accumulative roll bonding (ARB) and asymmetric rolling (AR). It was found that this improves both strength and ductility. TEM results show that the laminate structures produced by ARB develop an inhomogeneous microstructure with nanoscale grains and abnormal coarsening in some grains during AR processing. Both these effects result in an improved ductility and strength. Using these rolled products, micro-cups of very small wall thickness/cup diameter ratio (1/200) have been successfully fabricated by micro-deep drawing without the need for annealing.

Yu, Hailiang; Tieu, Kiet; Hadi, Syamsul; Lu, Cheng; Godbole, Ajit; Kong, Charlie

2015-02-01

271

Texture analysis of cold rolled and annealed aluminum alloy produced by twin-roll casting  

Directory of Open Access Journals (Sweden)

Full Text Available A 7.4 mm thick strip of 3003 aluminum alloy produced by the industrial twin-roll casting (TRC process was homogenized at 500 °C for 12 hours, after which it was cold rolled in two conditions: 1 to reduce the strip's thickness by 67%, and 2 to reduce it by 91%. The alloy was annealed at 400 °C for 1 hour in both conditions. The results revealed that a rotated cube texture, the {001} component, predominated in the as-cast condition and was transformed into brass, copper and S type textures during the cold rolling process. There was practically no difference between the deformation textures at the two thickness reductions.

Juliana de Paula Martins

2012-02-01

272

Texture analysis of cold rolled and annealed aluminum alloy produced by twin-roll casting  

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: English Abstract in english A 7.4 mm thick strip of 3003 aluminum alloy produced by the industrial twin-roll casting (TRC) process was homogenized at 500 °C for 12 hours, after which it was cold rolled in two conditions: 1) to reduce the strip's thickness by 67%, and 2) to reduce it by 91%. The alloy was annealed at 400 °C for [...] 1 hour in both conditions. The results revealed that a rotated cube texture, the {001} component, predominated in the as-cast condition and was transformed into brass, copper and S type textures during the cold rolling process. There was practically no difference between the deformation textures at the two thickness reductions.

Juliana de Paula, Martins; André Luis Moreira de, Carvalho; Angelo Fernando, Padilha.

2012-02-01

273

Low Band Gap Polymers for Roll-to-Roll Coated Organic Photovoltaics – Design, Synthesis and Characterization  

DEFF Research Database (Denmark)

In this paper we present the design and synthesis of 25 new low band gap polymers. The polymers were characterized by UV-vis spectroscopy which showed optical band gaps of 2.0–0.9 eV. The polymers which were soluble enough were applied in organic photovoltaics, both small area devices with a spin coated active layer and in large area modules where all layers including the active layer were either roll-to-roll coated or printed. These experiments showed that the design of polymers compatible with roll-toroll coating is not straightforward and that there are various issues such as donor/acceptor fitting within the polymer, side chains to ensure solubility and HOMO/LUMO level alignment with the acceptor (e.g. [60]PCBM) to take into consideration.

Bundgaard, Eva; Hagemann, Ole

2011-01-01

274

Rolls-Royce digital Rod Control System  

International Nuclear Information System (INIS)

Full text of publication follows: Rolls-Royce has developed a new generation of Rod Control System, based on 40 years of experience. The fifth-generation Rod Control System (RCS) from Rolls-Royce offers a reliable, modular design with adaptability to your preferred platform, for modernization projects or new reactors. Flexible implementation provides the option for you to keep existing cabinets, which permits you to optimize installation approach. Main features for the power part: - Control Rod Drive Mechanism (CRDM) type: 3-coil. - Independent control of each sub-bank. - Each sub-bank is controlled by a cycler unit and 3 identical power racks, each including 4 identical power modules and a common power-supply module. - Coil-per-coil digital control: each power module embeds power-conversion, current-control, and current-monitoring functions for one coil. Control and monitoring are carried out by separate electronics in the module. Current is digitized and fully monitored by means of min-max templates. - A double-hold function is included: a power module assigned to a gripper will activate its coil if a fault risking to cause a reactor trip occurs. - Power modules are standardized, hot-pluggable and self-configured: a power module includes a set of parameters for each type of coil SG, MG, LC. The module recognizes the rack it is plugged in, and chooses automatically parameters to be used. Main benefits: - Reduced operational, maintenance, training, and inventory costsmaintenance, training, and inventory costs: standardization of power modules and integration of control and monitoring on the same PC-card lead to a drastic reduction of spare part types, and simplification of the system. - Easy maintenance: - Replacement of a power module solves nearly all failures due to current control or monitoring for a coil. It is done instantly thanks to hot-plug capability. - On the front plate of power-modules, LEDs provide useful information for diagnostic: current setpoint from cycler, output current bar-graph representing min-max monitoring thresholds, and grouped faults. Plugs allow output current checking per coil. - From the cycler, the output current can be forced on a rack for test, while ensuring that rods are held by another available gripper rack. - Low power dissipation: no need for multiplexing or LC-inhibition thyristors - Commissioning: 3-thyristor well-tried half bridges (no energy storage), fuses for protection of feed-through penetrations. The paper will present in details the technical features of the Rolls-Royce Rod Control System and the main benefits to use it. About Rolls-Royce Rolls-Royce is a global business providing integrated power systems for use on land, at sea and in the air. The Group has a balanced business portfolio with leading market positions. Rolls-Royce has a broad range of civil nuclear expertise, including work related to licensing and safety reviews, engineering design, supply chain management, manufacturing, installation and commissioning of the nuclear island systems and equipments, as well as operational management and through life support. Rolls-Royce benefits of a strong reputation worldwide and of a unique experience in the nuclear market. (author)

275

Rolls-Royce digital Rod Control System  

Energy Technology Data Exchange (ETDEWEB)

Full text of publication follows: Rolls-Royce has developed a new generation of Rod Control System, based on 40 years of experience. The fifth-generation Rod Control System (RCS) from Rolls-Royce offers a reliable, modular design with adaptability to your preferred platform, for modernization projects or new reactors. Flexible implementation provides the option for you to keep existing cabinets, which permits you to optimize installation approach. Main features for the power part: - Control Rod Drive Mechanism (CRDM) type: 3-coil. - Independent control of each sub-bank. - Each sub-bank is controlled by a cycler unit and 3 identical power racks, each including 4 identical power modules and a common power-supply module. - Coil-per-coil digital control: each power module embeds power-conversion, current-control, and current-monitoring functions for one coil. Control and monitoring are carried out by separate electronics in the module. Current is digitized and fully monitored by means of min-max templates. - A double-hold function is included: a power module assigned to a gripper will activate its coil if a fault risking to cause a reactor trip occurs. - Power modules are standardized, hot-pluggable and self-configured: a power module includes a set of parameters for each type of coil SG, MG, LC. The module recognizes the rack it is plugged in, and chooses automatically parameters to be used. Main benefits: - Reduced operational, maintenance, training, and inventory costs: standardization of power modules and integration of control and monitoring on the same PC-card lead to a drastic reduction of spare part types, and simplification of the system. - Easy maintenance: - Replacement of a power module solves nearly all failures due to current control or monitoring for a coil. It is done instantly thanks to hot-plug capability. - On the front plate of power-modules, LEDs provide useful information for diagnostic: current setpoint from cycler, output current bar-graph representing min-max monitoring thresholds, and grouped faults. Plugs allow output current checking per coil. - From the cycler, the output current can be forced on a rack for test, while ensuring that rods are held by another available gripper rack. - Low power dissipation: no need for multiplexing or LC-inhibition thyristors - Commissioning: 3-thyristor well-tried half bridges (no energy storage), fuses for protection of feed-through penetrations. The paper will present in details the technical features of the Rolls-Royce Rod Control System and the main benefits to use it. About Rolls-Royce Rolls-Royce is a global business providing integrated power systems for use on land, at sea and in the air. The Group has a balanced business portfolio with leading market positions. Rolls-Royce has a broad range of civil nuclear expertise, including work related to licensing and safety reviews, engineering design, supply chain management, manufacturing, installation and commissioning of the nuclear island systems and equipments, as well as operational management and through life support. Rolls-Royce benefits of a strong reputation worldwide and of a unique experience in the nuclear market. (author)

Pouillot, M. [Rolls-Royce Civil Nuclear SAS (France)

2010-07-01

276

A roll-to-roll welding process for planarized silver nanowire electrodes  

Science.gov (United States)

We demonstrate continuous roll-to-roll production of highly conductive silver network films on a plastic substrate via mechanical and chemical welding processes. This process included three essential steps: (i) solvent spraying, (ii) roll compression, and (iii) salt treatment and washing. The sheet resistance of the resulting AgNW film was 5 ? sq-1 at 92% transmittance, which was the lowest sheet resistance and the highest transparency among the values reported previously for solution-processed AgNW electrodes. Moreover, the strong contacts among the AgNWs dramatically enhanced the mechanical stability of the network film. The resulting AgNW film was successfully applied to various organic electronic devices, such as organic field-effect transistors (OFETs), organic light-emitting diodes (OLEDs), and organic solar cells (OSCs).We demonstrate continuous roll-to-roll production of highly conductive silver network films on a plastic substrate via mechanical and chemical welding processes. This process included three essential steps: (i) solvent spraying, (ii) roll compression, and (iii) salt treatment and washing. The sheet resistance of the resulting AgNW film was 5 ? sq-1 at 92% transmittance, which was the lowest sheet resistance and the highest transparency among the values reported previously for solution-processed AgNW electrodes. Moreover, the strong contacts among the AgNWs dramatically enhanced the mechanical stability of the network film. The resulting AgNW film was successfully applied to various organic electronic devices, such as organic field-effect transistors (OFETs), organic light-emitting diodes (OLEDs), and organic solar cells (OSCs). Electronic supplementary information (ESI) available. See DOI: 10.1039/c4nr03771e

Lee, Seong Jun; Kim, Young-Hoon; Kim, Jung Kyu; Baik, Hionsuck; Park, Jae Hoon; Lee, Jaeki; Nam, Jaewook; Park, Jong Hyeok; Lee, Tae-Woo; Yi, Gi-Ra; Cho, Jeong Ho

2014-09-01

277

Towards Realizing High-Throughput, Roll-to-Roll Manufacturing of Flexible Electronic Systems  

Directory of Open Access Journals (Sweden)

Full Text Available High-rate roll-to-roll (R2R tracker systems are utilized for large volume flexible electronic device manufacturing, and the current alignment mechanism between layers is mainly achieved by relying on passive techniques. In this paper, we present a machine vision based alignment strategy that is used to achieve precise registration for stacking multilayers. Based on this strategy, we demonstrate two-layer printing with alignment accuracy better than 100 ?m in web moving direction and 200 ?m in lateral direction at a web rate of 5 m/min.

Xiaohui Lin

2014-11-01

278

Large-scale roll-to-roll photonic sintering of flexo printed silver nanoparticle electrodes  

Digital Repository Infrastructure Vision for European Research (DRIVER)

In this report we employ static and roll-to-roll (R2R) photonic sintering processes on flexo printed silver nanoparticle-based electrode structures with a heat-sensitive 60 mm thin barrier foil as a substrate.We use large area electrode structures to visualize the increased optical footprint of single and quadruple flashes, and the R2R challenges in the form of overlapping exposures. It is shown that single flash exposure is enough to significantly increase the conductivity and adhesion ...

Ho?sel, Markus; Krebs, Frederik C.

2012-01-01

279

Texture analysis of cold rolled and annealed aluminum alloy produced by twin-roll casting  

Digital Repository Infrastructure Vision for European Research (DRIVER)

A 7.4 mm thick strip of 3003 aluminum alloy produced by the industrial twin-roll casting (TRC) process was homogenized at 500 °C for 12 hours, after which it was cold rolled in two conditions: 1) to reduce the strip's thickness by 67%, and 2) to reduce it by 91%. The alloy was annealed at 400 °C for 1 hour in both conditions. The results revealed that a rotated cube texture, the {001} component, predominated in the as-cast condition and was transformed into brass, copper and S type tex...

Juliana de Paula Martins; André Luis Moreira de Carvalho; Angelo Fernando Padilha

2012-01-01

280

Latent and Manifested flatness predictions in thin strip cold rolling using a general rolling FEM model  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Flatness defects in thin strip cold rolling are a consequence of roll thermo-elastic deformation and the resulting heterogeneous strip plastic deformation. But in the case of on-line, manifested flatness defects, buckling reorganizes the stress field in the pre- and post-bite areas, which might impact strain and stress fields in the bite or at its ends. Such effects have always been neglected in the past. The purpose of the present paper is to present two coupled approaches to examine to what...

Abdelkhalek, Sami; Zahrouni, Hamid; Montmitonnet, Pierre; Legrand, Nicolas; Potier-ferry, Michel

2011-01-01

 
 
 
 
281

Development of a twin roll caster for light metals  

Directory of Open Access Journals (Sweden)

Full Text Available Purpose: Purpose of this paper is to show the development of a twin roll caster for aluminium alloy. One of the developments was the increase of the roll speed. The increase of the roll speed was essential to improve the low productivity of the twin roll caster. Limitation of the alloys, which can be cast into the strip, could be enlarged by the method to increase the roll speed. The method to increase the roll speed was useful to increase the cooling rate of the cast strip. The devices to increase the roll speed were shown in this paper. Other development was invention of the twin roll caster to cast clad strip. The twin roll casters to cast two layers clad strip, three layers clad strip and five layers clad strip were invented.Design/methodology/approach: Increase of roll speed was attained by the use of a copper roll and a nozzle, operation of the low temperature casting and non-use of parting material. A scraper was adopted to the twin roll caster for clad strip to prevent the mixture of the molten metals and to control the surface condition. The devices to increase the roll speed were useful for the roll caster to cast clad strip.Findings: The aluminium alloy strip could be cast at the speeds up to 90 m/min. The aluminium alloy which has wide freezing zone like Al-25%Si could be cast into the strip. Two layers, three layers and five layers of clad strips could be cast.Research limitations/implications: The roll casters were laboratory size. Therefore, it was not clear of the ability of the casting of the long size and wide size strips.Practical implications: The productivity of aluminium alloy strip is increased. The property of the aluminium alloy strip is improved. The aluminium alloy, which was too brittle to be formed into the plate, will be cast into strip directly from melt. The process and energy to make the brazing sheet will be saved by the roll caster of the present study.Originality/value: The invented roll casters, devices for casting and properties of the cast strips are original.

T. Haga

2010-11-01

282

High resolution UV roll-to-roll nanoimprinting of resin moulds and subsequent replication via thermal nanoimprint lithography  

International Nuclear Information System (INIS)

UV roll-to-roll nanoimprinting at high resolution is still a relatively unexplored field of study with far-reaching application potential. One enabling technology that is particularly worthy of attention is mass production of high resolution resin moulds via UV roll-to-roll nanoimprinting at such high throughput and low cost that they can be used only once and disposed of or recycled economically. Low cost, high resolution resin moulds can greatly improve the production cost profile for a number of applications in biomedicine, nanofluidics, data storage and electronics with relatively low unit values but which require one or more nanoscale lithography steps. In this report, UV roll-to-roll nanoimprinting was employed to fabricate high fidelity resin moulds with nanoscale as well as mixed micro- and nanoscale features down to 50 nm feature diameter, at up to 120 cm2 area and at 10 m min?1 throughput. UV roll-to-roll nanoimprinted resin moulds were subsequently segmented out, employed in a batch mode thermal nanoimprinting process, and characterized to study performance and demonstrate viability. The results show that high resolution mixed nanostructures can be faithfully replicated in PMMA on silicon substrates with minimal volumetric shrinkage. Process details and challenges specific to roll-to-roll fabrication of resin moulds are discussed at length, particularly with respect to the curvature uniformity of the imprint roller. (paper)of the imprint roller. (paper)

283

The theory and technique of yamuna body rolling.  

Science.gov (United States)

[Purpose] This paper provides information about the theory and technique of Yamuna Body Rolling. In order to treat physical problems, using the specialized Yamuna Body Rolling balls, people can target superficial skin, fasciae, muscle fibers, tendons, ligaments, bones, internal organs, and the nervous system by themselves. The extraordinary effect of Yamuna Body Rolling is its multidimensional elongation of muscle fibers. In addition to the regular longitudinal elongation by the conventional stretch method, Yamuna Body Rolling enables the transversal and diagonal expansion of muscle fibers in order to move the body more dynamically. Hamstring, abdominal, and sideline routines are presented as examples for techniques of Yamuna Body Rolling. Yamuna Body Rolling can be applied to functional evaluation and therapeutic uses; therefore, it could provide many benefits in the treatment of different conditions in the medical field. PMID:24259945

Suzuki, Satoshi

2013-09-01

284

Estimation of Parametric Roll in a Stochastic Seaway  

DEFF Research Database (Denmark)

The present paper describes a model for prediction of parametric roll which is sufficiently fast to give predictions in real time for the probability of different levels of parametric roll angles in given long crested sea states. The procedure is based on an extension of a simplified two-degree of freedom (roll and heave) time domain model [10]. In the present paper the effect of the increased added resistance when the bow heaves and pitches down in a wave crest is introduced. Due to the resulting forward speed variation the roll resonance condition will be changed. The influence of ship speed on roll angle has in the past been noted by e.g. [6], where large roll angles in combination with the ship speed reduction can be seen from time traces from model tests.

Jensen, JØrgen Juncher; Pedersen, Preben Terndrup

2008-01-01

285

Multilayer roll bonded aluminium foil: processing, microstructure and flow stress  

International Nuclear Information System (INIS)

Bulk aluminium has been produced by warm-rolling followed by cold-rolling of commercial purity (99% purity) aluminium foil. The bonding appeared perfect from observation with the naked eye, light and transmission electron microscopy. By comparison with bulk aluminium of similar purity (AA1200) rolled to a similar strain (90%RA), the roll-bonded metal showed a much higher density of high-angle grain boundaries, similar strength and improved thermal stability. This study has implications for a number of applications in relation to the processing of aluminium. Roll bonding is of interest as a method for grain size refinement; oxide-containing materials have increased strength, enhanced work-hardening behaviour, and exhibit alterations in recrystallisation behaviour. The behaviour of the hard oxide film is of interest in aluminium processing, and has been investigated by characterising the size and distribution of oxide particles in the roll-bonded samples

286

Numerical and experimental analysis of lubrication in strip cold rolling  

Directory of Open Access Journals (Sweden)

Full Text Available In this work an analytical model based on the slab method was built to analyze the lubrication during cold rolling of aluminum strips. Some process variables were studied like the rolling speed, the cross-section reduction, and lubricant viscosity. Numerical results are presented for pressure variation and film thickness at the inlet and work zones. The loads necessary to separate the rolls are also estimated. Some experimental results are shown for the surface roughness of the rolled products. It is shown that analytical results are in good accordance to experimental results, and that rolling pressure, lubricant film thickness and surface roughness are strongly influenced by rolling conditions, especially the lubricant viscosity and the area reduction.

Sérgio Tonini Button

2011-06-01

287

Numerical and experimental analysis of lubrication in strip cold rolling  

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: English Abstract in english In this work an analytical model based on the slab method was built to analyze the lubrication during cold rolling of aluminum strips. Some process variables were studied like the rolling speed, the cross-section reduction, and lubricant viscosity. Numerical results are presented for pressure variat [...] ion and film thickness at the inlet and work zones. The loads necessary to separate the rolls are also estimated. Some experimental results are shown for the surface roughness of the rolled products. It is shown that analytical results are in good accordance to experimental results, and that rolling pressure, lubricant film thickness and surface roughness are strongly influenced by rolling conditions, especially the lubricant viscosity and the area reduction.

Sérgio Tonini, Button.

2011-06-01

288

ANALYSIS OF ROLLING GROUP THERAPY DATA USING CONDITIONALLY AUTOREGRESSIVE PRIORS  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Group therapy is a central treatment modality for behavioral health disorders such as alcohol and other drug use (AOD) and depression. Group therapy is often delivered under a rolling (or open) admissions policy, where new clients are continuously enrolled into a group as space permits. Rolling admissions policies result in a complex correlation structure among client outcomes. Despite the ubiquity of rolling admissions in practice, little guidance on the analysis of such da...

Paddock, Susan M.; Hunter, Sarah B.; Watkins, Katherine E.; Mccaffrey, Daniel F.

2011-01-01

289

Temperature and heat flux fast estimation during rolling process  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Monitoring and controlling flatness during the rolling process becomes critical for ensuring the product quality. Flatness defects are due to highly three-dimensional phenomena. Indeed, strips with different widths are rolled during the same campaign and cooling systems are heterogeneous along the axial direction to modify the thermal expansion of the roll. Therefore this paper presents a fully three-dimensional inverse analytical method to determine the temperature field and heat fluxes (esp...

Weisz-patrault, Daniel; Ehrlacher, Alain; Legrand, Nicolas

2014-01-01

290

Adaptive attenuation of aliased ground roll using the shearlet transform  

Science.gov (United States)

Attenuation of ground roll is an essential step in seismic data processing. Spatial aliasing of the ground roll may cause the overlap of the ground roll with reflections in the f-k domain. The shearlet transform is a directional and multidimensional transform that separates the events with different dips and generates subimages in different scales and directions. In this study, the shearlet transform was used adaptively to attenuate aliased and non-aliased ground roll. After defining a filtering zone, an input shot record is divided into segments. Each segment overlaps adjacent segments. To apply the shearlet transform on each segment, the subimages containing aliased and non-aliased ground roll, the locations of these events on each subimage are selected adaptively. Based on these locations, mute is applied on the selected subimages. The filtered segments are merged together, using the Hanning function, after applying the inverse shearlet transform. This adaptive process of ground roll attenuation was tested on synthetic data, and field shot records from west of Iran. Analysis of the results using the f-k spectra revealed that the non-aliased and most of the aliased ground roll were attenuated using the proposed adaptive attenuation procedure. Also, we applied this method on shot records of a 2D land survey, and the data sets before and after ground roll attenuation were stacked and compared. The stacked section after ground roll attenuation contained less linear ground roll noise and more continuous reflections in comparison with the stacked section before the ground roll attenuation. The proposed method has some drawbacks such as more run time in comparison with traditional methods such as f-k filtering and reduced performance when the dip and frequency content of aliased ground roll are the same as those of the reflections.

Hosseini, Seyed Abolfazl; Javaherian, Abdolrahim; Hassani, Hossien; Torabi, Siyavash; Sadri, Maryam

2015-01-01

291

Entry Strategies to Indonesian Market Case: MoveaRoll  

Digital Repository Infrastructure Vision for European Research (DRIVER)

MoveRoll Oy, an internationally growing and expanding Finnish company located in Porvoo, has invented a unique technology to produce a paper roll conveyor which the company believes will revolutionise the paper roll handling industry. Moreover, after establishing itself in the Finnish market, the company has started expanding its business to countries like Sweden, USA, and China. Likewise, the process of expanding to the Russian market is currently underway and the company has recently launch...

Islam, Zahedul

2013-01-01

292

Study of peculiar features of deformation heterogeneity on rolling  

International Nuclear Information System (INIS)

The development of deformation localization bands is studied on VT8 and OT4 titanium alloy specimens which differ in pretreatments (forging and rolling) and structures. Deformation bands were revealed on transverse macrosections. Almost similar character of deformation heterogeneity is marked both for forged and rolled specimens. The data on deformation localization can be used for selection of rolling conditions for titanium alloys provided for sound products

293

Covalent Immobilization of P-selectin Enhances Cell Rolling  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Cell rolling is an important physiological and pathological process that is used to recruit specific cells in the bloodstream to a target tissue. This process may be exploited for biomedical applications to capture and separate specific cell types. One of the most commonly studied proteins that regulate cell rolling is P-selectin. By coating surfaces with this protein, biofunctional surfaces that induce cell rolling can be prepared. Although most immobilization methods have relied on physisor...

Hong, Seungpyo; Lee, Dooyoung; Zhang, Huanan; Zhang, Jennifer Q.; Resvick, Jennifer N.; Khademhosseini, Ali; King, Michael R.; Langer, Robert; Karp, Jeffrey M.

2007-01-01

294

High speed twin roll caste for aluminum alloy thin strip  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Purpose: In the present study, effectiveness of a high-speed twin roll caster for recycling aluminum alloy was investigated.Design/methodology/approach: The effects of the high-speed twin roll caster on alleviating the deterioration of mechanical properties by impurities were investigated. Properties of the cast strip were investigated by metalography, a tension test, and a bending test.Findings: A vertical type twin roll caster for strip casting of aluminum alloys was devised. The strip, whi...

Haga, T.; Inui, H.; Sakaguchi, H.; Watari, H.; Kumaic, S.

2007-01-01

295

Advanced hot rolling strategies for IF and TRIP steels:  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Steel producers are forced to reduce the production cost on the one hand and increase the performances of the products on the other hand, to maintain or even increase their market share. A likely method to save on production costs is to cut down the rather long production chain for conventional cold rolled strip, and to substitute certain cold rolled steel grades by hot rolled steel. Certainly this can rarely be achieved for exposed parts, requiring a perfect surface finish, whereas for unexp...

Elsner, A.

2005-01-01

296

Multi-Stage FE Simulation of Hot Ring Rolling  

Digital Repository Infrastructure Vision for European Research (DRIVER)

As a unique and important member of the metal forming family, ring rolling provides a cost effective process route to manufacture seamless rings. Applications of ring rolling cover a wide range of products in aerospace, automotive and civil engineering industries [1]. Above the recrystallization temperature of the material, hot ring rolling begins with the upsetting of the billet cut from raw stock. Next a punch pierces the hot upset billet to form a hole through the billet. This billet, refe...

Wang, C.; Geijselaers, H. J. M.; Boogaard, A. H. Den

2013-01-01

297

Rolling Bearing Diagnosis Based on LMD and Neural Network  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Inner ring pitting, the outer indentation and rolling element wear are typical faults of rolling bearing. In order to diagnose these faults rapidly and accurately, the paper proposes a novel diagnosis method of rolling bearing based on the energy characteristics of PF component and neural network by the vibration signal of local mean decomposition(Local mean decomposition, LMD). The vibration signal is decomposed into several PF components by the local mean decomposition, the calculated energ...

Baoshan Huang; De, Wei; Wei Xu; Xinfeng Zou

2013-01-01

298

On Fail-Rolle polynomials with few roots  

Directory of Open Access Journals (Sweden)

Full Text Available A splitting polynomial in one variable over a field is Fail-Rolle if its formal derivative does not split over the same field. It is known that the finite fields with more than four elements are exactly the finite fields for which there are Fail-Rolle polynomials. We describe all Fail-Rolle polynomials with at most five roots over a finite field of even characteristic.

L. H. Gallardo

2010-02-01

299

Development and Fabrication of Pineapple Rolled Tart Machine  

Digital Repository Infrastructure Vision for European Research (DRIVER)

A pineapple rolled tart machine is required in the manufacturing of pineapple rolled tart. In this research, a machine that would reduce processing time and operating cost and that would be affordable for small-scale industries was designed. The machine was tested at different screw rotating speeds and dough formulations. The rolled tart throughput rates were significantly increased (p<0.05) with screw rotating speeds and butter percentages of dough. However, it was significantly decreased (p...

Azman Hamzah; Rosnah Shamsudin; Pua Ming Yee; Johari Endan

2011-01-01

300

Recrystallization behavior of cold-rolled Zr 702  

Science.gov (United States)

Using the hardness test, we determined the recrystallization kinetics of cold-rolled Zr 702. The rate of the recrystallization process increased with increasing annealing temperature and rolling reduction. The Johnson-Mehl-Avrami-Kolmogorov (JMAK) exponent obtained was less than 1, which also increased with increasing annealing temperature and rolling reduction. The activation energies for the recrystallization of the 38.9% and 71.0% cold-rolled sheets were 232 kJ/mol and 251 kJ/mol, respectively.

Li, M. H.; Ma, M.; Liu, W. C.; Yang, F. Q.

2013-02-01

 
 
 
 
301

Troll, a Language for specifying Dice-rolls  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Dice are used in many games, and often in fairly complex ways that make it difficult to unambiguously describe the dice-roll mechanism in plain language. Many role-playing games, such as Dungeons & Dragons, use a formalised notation for some instances of dice-rolls. This notation, once explained, make dice-roll descriptions concise and unambiguous. Furthermore, the notation has been used in automated tools for pseudo-random dice-rolling (typically used when playing over the Internet). This no...

Mogensen, Torben Ægidius

2009-01-01

302

The effects of forming parameters on conical ring rolling process.  

Science.gov (United States)

The plastic penetration condition and biting-in condition of a radial conical ring rolling process with a closed die structure on the top and bottom of driven roll, simplified as RCRRCDS, were established. The reasonable value range of mandrel feed rate in rolling process was deduced. A coupled thermomechanical 3D FE model of RCRRCDS process was established. The changing laws of equivalent plastic strain (PEEQ) and temperature distributions with rolling time were investigated. The effects of ring's outer radius growth rate and rolls sizes on the uniformities of PEEQ and temperature distributions, average rolling force, and average rolling moment were studied. The results indicate that the PEEQ at the inner layer and outer layer of rolled ring are larger than that at the middle layer of ring; the temperatures at the "obtuse angle zone" of ring's cross-section are higher than those at "acute angle zone"; the temperature at the central part of ring is higher than that at the middle part of ring's outer surfaces. As the ring's outer radius growth rate increases at its reasonable value ranges, the uniformities of PEEQ and temperature distributions increase. Finally, the optimal values of the ring's outer radius growth rate and rolls sizes were obtained. PMID:25202716

Meng, Wen; Zhao, Guoqun; Guan, Yanjin

2014-01-01

303

Arvuti roll elementaarmatemaatika õppimisel ja õpetamisel / Margo Kikas  

Index Scriptorium Estoniae

Juuni algul toimus TPÜ-s kolmepäevane kursus "Arvuti roll elementaarmatemaatika õppimisel ja õpetamisel", kus põhiesinejaks oli The Royal Danish School of Educational Studies (Taani) õppejõud Viggo Sadolin

Kikas, Margo, 1974-

1998-01-01

304

On wear in rolling/sliding contacts  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The aim of this thesis is to increase the understanding of wear in rolling/sliding contacts such as the wheel-rail contact for railroads and the roller-washer contact for roller bearings. The Stockholm commuter train network has been the subject of papers A and B in this thesis in which the wear and surface cracks on rails has been observed for a period of three years. By comparing the wear depth with the crack length, equilibrium between these two damage mechanisms was found for a lubricated...

Nilsson, Rickard

2005-01-01

305

Running-in of rolling contacts  

Digital Repository Infrastructure Vision for European Research (DRIVER)

This thesis deals with running-in of the pure rolling contact situation operating in the boundary lubrication regime, so that normal plastic deformation due to the contact between asperities is the main aspect. The change of the surface topography during the running-in process and the run-in surfaces are predicted locally. The main theme concerns the elastic-plastic asperity contact model. An asperity micro-contact model was considered due to its analytical nature and a well-ploughed study. A...

Jamari, J.

2006-01-01

306

Corrosion behaviour of different hot rolled steels  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The oxidation-corrosion behaviour of hot rolled alloys was examined by electrochemical impedance spectroscopy. The corrosion behaviour of the non-oxidised alloys was first determined in order to have a reference behaviour. Then, each alloy was oxidised for 1 and 3 days at 650 degrees C in air and its corrosion behaviour was also determined. For all the alloys, Fe2O3 was formed at the scale-gas interface. However, the Fe2O3 crystallographic structures varied as a function of the alloy composit...

Perez, F. J.; Martinez, L.; Hierro, M. P.; Gomez, C.; Portela, A. L.; Pucci, G. N.; Duday, D.; Lecomte-beckers, Jacqueline; Greday, Y.

2006-01-01

307

Ledelsens rolle i implementeringen af folkeskolereformen  

DEFF Research Database (Denmark)

Ét er den politiske beslutning om folkeskolereformen. Noget ganske andet er, hvorledes og hvorvidt reformen resulterer i en forandret pædagogisk praksis. Denne artikel sigter mod at bidrage med en øget forståelse af især ledelsens rolle i implementeringen af skolereformen ved at belyse de forhold, der præger offentlige implementeringsprocesser. Det er komplekse forhold, der hæmmer eller fremmer de offentlige implementeringsprocesser. Hvis vi oversimplificerer disse processer i forenklede modeller uden viden og forståelse for det bagvedliggende, så risikerer vi at overse væsentlige og potentielt afgørende forhold, der påvirker dem.

Conrad, Torsten

2014-01-01

308

Spoilers for roll control of light airplanes  

Science.gov (United States)

The paper presents an overview of the state-of-the-art of roll control spoilers for light airplanes. Reasons for using spoilers on light airplanes are presented. Several classical objections to the use of spoilers of such airplanes are critically examined. It is shown that mechanically driven spoiler systems can be designed. Flight test results of a new mechanically driven spoiler on the Redhawk airplane are discussed. Tunnel data of spoilers on the new general aviation airfoil GA(W)-1 are presented. Finally, a bibliography on spoiler data is included.

Roskam, J.; Kohlman, D. L.; Wentz, W. H.

1974-01-01

309

Rudder-Roll Damping Autopilot Robustness to Sway-Yaw-Roll Couplings  

DEFF Research Database (Denmark)

Contributions of the paper are to advise ways to access the effects of coupling term changes on RRD control, to show the changes in robustness, including roll reduction capability for various parameters, and to provide a complete, parameterized model that can be used for comparison of methodology in RRD design

Blanke, M.; Christensen, A.C.

1993-01-01

310

Low Band Gap Polymers for Roll-to-Roll Coated Polymer Solar Cells  

DEFF Research Database (Denmark)

We present the synthesis of a low band gap copolymer based on dithienothiophene and dialkoxybenzothiadiazole (poly(dithienothiophene-co-dialkoxybenzothiadiazole), PDTTDABT). The optical properties of the polymer showed a band gap of 1.6 eV and a sky-blue color in solid films. The polymer was explored in roll-to-roll coating experiments and was optimized with respect to the manufacturing process and mixing ratio with [60]PCBM through a series of experiments with variation of the composition in steps of 1% w/w of respectively PDTTDABT and [60]PCBM and a relatively broad optimimum was found around a 1:2 mixing ratio. Roll-to-roll coated polymer solar cell devices were prepared under ambient conditions employing solution processing in all steps including the metallic back electrode that was printed as a grid giving semitransparent solar cell devices. Solar cell modules comprising 16 serially connected cells were prepared with a total module active area of 96 cm2. The devices were tested for operational stability under simulated sunlight (AM1.5G) and natural sunlight, and the photochemical stability of the polymer was examined using a combination of UV?vis and IR spectroscopy.

Bundgaard, Eva; Hagemann, Ole

2010-01-01

311

Upscaling of polymer solar cell fabrication using full roll-to-roll processing  

Science.gov (United States)

Upscaling of the manufacture of polymer solar cells is detailed with emphasis on cost analysis and practical approach. The device modules were prepared using both slot-die coating and screen printing the active layers in the form of stripes that were serially connected. The stripe width was varied and the resultant performance analysed. Wider stripes give access to higher geometric fill factors and lower aperture loss while they also present larger sheet resistive losses. An optimum was found through preparation of serially connected stripes having widths of 9, 13 and 18 mm with nominal geometric fill factors (excluding bus bars) of 50, 67 and 75% respectively. In addition modules with lengths of 6, 10, 20, 22.5 and 25 cm were explored. The devices were prepared by full roll-to-roll solution processing in a web width of 305 mm and roll lengths of up to 200 m. The devices were encapsulated with a barrier material in a full roll-to-roll process using standard adhesives giving the devices excellent stability during storage and operation. The total area of processed polymer solar cell was around 60 m2 per run. The solar cells were characterised using a roll-to-roll system comprising a solar simulator and an IV-curve tracer. After characterisation the solar cell modules were cut into sheets using a sheeting machine and contacted using button contacts applied by crimping. Based on this a detailed cost analysis was made showing that it is possible to prepare complete and contacted polymer solar cell modules on this scale at an area cost of 89 € m-2 and an electricity cost of 8.1 € Wp-1. The cost analysis was separated into the manufacturing cost, materials cost and also the capital investment required for setting up a complete production plant on this scale. Even though the cost in € Wp-1 is comparable to the cost for electricity using existing technologies the levelized cost of electricity (LCOE) is expected to be significantly higher than the existing technologies due to the inferior operational lifetime. The presented devices are thus competitive for consumer electronics but ill-suited for on-grid electricity production in their current form.

Krebs, Frederik C.; Tromholt, Thomas; Jørgensen, Mikkel

2010-06-01

312

Scalable, ambient atmosphere roll-to-roll manufacture of encapsulated large area, flexible organic tandem solar cell modules  

DEFF Research Database (Denmark)

Inline printing and coating methods have been demonstrated to enable a high technical yield of fully roll-to-roll processed polymer tandem solar cell modules. We demonstrate generality by employing different material sets and also describe how the ink systems must be carefully co-developed in order to reach the ambitious objective of a fully printed and coated 14-layer flexible tandem solar cell stack. The roll-to-roll methodologies involved are flexographic printing, rotary screen printing, slot-die coating, X-ray scattering, electrical testing and UV-lamination. Their combination enables the manufacture of completely functional devices in exceptionally high yields. Critical to the ink and process development is a carefully chosen technology transfer to industry method where first a roll coater is employed enabling contactless stack build up, followed by a small roll-to-roll coater fitted to an X-ray machine enabling in situ studies of wet ink deposition and drying mechanisms, ultimately elucidating how a robust inline processed recombination layer is key to a high technical yield. Finally, the transfer to full roll-to-roll processing is demonstrated.

Andersen, Thomas Rieks; Dam, Henrik Friis

2014-01-01

313

Effect of the rolling speed on microstructural and mechanical properties of aluminum-magnesium alloys prepared by twin roll casting  

International Nuclear Information System (INIS)

In the present investigation the microstructures and mechanical properties of Al-Mg alloys prepared by twin roll casting (TRC), varying rolling speed, (i.e., 3, 4, and 5 rpm) were studied. Optical microstructures of the all the samples show dendritic morphology. Scanning electron microscopy (SEM) and energy dispersive X-ray spectrometer (EDS) studies show segregation of alloying elements at the interdendritic regions. Transmission electron microscopy (TEM) observation confirms the presence of intermetallic phase (Mg5Al8) at the grain boundaries. It was observed that the secondary dendritic arm spacing (SDAS) increases (marginally) with rolling speed. Also the microhardness and tensile strength decreases with increase in rolling speed.

314

Powder lubrication of faults by powder rolls in gouge zones  

Science.gov (United States)

Powder-lubrication by fault gouge can be an effective mechanism of dynamic weakening of faults (Reches & Lockner, 2010); however, the physical mechanisms of this lubrication are poorly understood. While the flow of coarse-grained (> 100 ?m) materials, e.g. glass beads or quartz sand, was extensively studied, the flow of fine-grained (granite, tonalite and diorite); and (2) fault-zones made of 2-3 mm thick layer of granular materials (oolites, calcite or gypsum) sheared in a confined cell. We performed 21 runs with total slip of 0.14-13 m, normal stress of 1.2-14.5 MPa, slip velocity of 0.012-0.97 m/s. The ultra-microscopic (SEM and AFM) analysis of the experimental slip surfaces revealed two outstanding features in 17 out of the 21 experiments: (1) localized fault-slip along Principal Slip Zones (PSZs) that are composed of a dense, shiny, cohesive crust, 0.5-1 micron thick, that overlaid a porous substrate, and (2) elongated rolls composed of gouge-powder into three-dimensional structures of closely-packed powder grains, (20-50 nm in size). The rolls are cylindrical, 0.75-1.4 micron wide, and 1.7-30 micron long, with smooth outer surface, and laminated, concentric layers of compacted grains. The rolls were exclusively found on the PSZs. Many rolls were destroyed fracturing and smearing on the PSZ, suggesting that the rolls underwent a life cycle of formation and destruction. Significant macroscopic friction reduction was measured in experiments with observed rolls, and no (or minor) friction reduction in the four experiments without rolls. The final, reduced friction coefficients have a general reciprocal relation to the rolls surface coverage, suggesting that increased development of rolls (= increasing surface coverage) enhanced fault weakening. We applied the Eldredge and Tabor (1955) model for rolling friction to the AFM observed morphology of the rolls and PSZs, and found good agreement between measured and modeled friction coefficients. We conclude that the measured friction reduction reflects a transition from sliding-dominated slip to rolling-dominated slip due to the presence and density of powder rolls. We further argue that powder rolling is an effective mechanism of powder lubrication, and that spontaneous growth of such rolls along crustal faults is likely to control earthquake weakening.

Chen, X.; Madden, A. S.; Reches, Z.

2013-12-01

315

High speed twin roll caste for aluminum alloy thin strip  

Directory of Open Access Journals (Sweden)

Full Text Available Purpose: In the present study, effectiveness of a high-speed twin roll caster for recycling aluminum alloy was investigated.Design/methodology/approach: The effects of the high-speed twin roll caster on alleviating the deterioration of mechanical properties by impurities were investigated. Properties of the cast strip were investigated by metalography, a tension test, and a bending test.Findings: A vertical type twin roll caster for strip casting of aluminum alloys was devised. The strip, which was thinner than 3 mm, could be cast at speeds higher than 60 m/min. Features of the twin roll casters are as below. Copper rolls were used and lubricant was not used in order to increase the casting speed. A casting nozzle was used to set the solidification length precisely. Heat transfer between melt and the roll was improved by hydrostatic pressure of the melt. Separating force was very small in order to prevent sticking of the strip to the roll. Low superheat casting was carried out in order to improve microstructure of the strip. In the present study, effectiveness of a high-speed and high-cooling rate twin roll caster of the present study for recycling aluminum alloy was investigated. Fe was added as impurity to 6063 and A356. The roll caster of the present study was useful to decrease the influence of impurity of Fe.Research limitations/implications: A high-speed twin roll caster of vertical type was designed and assembled to cast aluminum alloy thin strip.Originality/value: The results demonstrate that the high-speed twin roll caster can improve the deterioration by impurities.

T. Haga

2007-09-01

316

Progress in cold roll bonding of metals  

Energy Technology Data Exchange (ETDEWEB)

Layered composite materials have become an increasingly interesting topic in industrial development. Cold roll bonding (CRB), as a solid phase method of bonding same or different metals by rolling at room temperature, has been widely used in manufacturing large layered composite sheets and foils. In this paper, we provide a brief overview of a technology using layered composite materials produced by CRB and discuss the suitability of this technology in the fabrication of layered composite materials. The effects of process parameters on bonding, mainly including process and surface preparation conditions, have been analyzed. Bonding between two sheets can be realized when deformation reduction reaches a threshold value. However, it is essential to remove surface contamination layers to produce a satisfactory bond in CRB. It has been suggested that the degreasing and then scratch brushing of surfaces create a strong bonding between the layers. Bonding mechanisms, in which the film theory is expressed as the major mechanism in CRB, as well as bonding theoretical models, have also been reviewed. It has also been showed that it is easy for fcc structure metals to bond compared with bcc and hcp structure metals. In addition, hardness on bonding same metals plays an important part in CRB. Applications of composites produced by CRB in industrial fields are briefly reviewed and possible developments of CRB in the future are also described. Corrections were made to the abstract and conclusion of this article on 18 June 2008. The corrected electronic version is identical to the print version. (topical review)

Li Long; Nagai, Kotobu; Yin Fuxing [Innovative Materials Engineering Laboratory, National Institute for Materials Science, Tsukuba 305-0047 (Japan)], E-mail: LI.Long@nims.go.jp

2008-04-01

317

Wear of rolling element bearings in sodium  

International Nuclear Information System (INIS)

Rolling element bearings and related mechanisms are attractive for service in liquid sodium but it is not clear what minimum wear rate can be anticipated. For axially loaded angular contact bearings rotation is incompatible with pure rolling on both races and wear arises from the resulting ball spin. The initial pressure distributions and sizes of the contact ellipses can be calculated but will change with bearing wear. However, the most effective distribution for producing wear would be for the full loads to be borne on the tips of the contact areas, whose maximum length is given by examination of the race wear tracks. A calculation on such a basis should set a lower limit for the wear coefficient. Both the torque and instantaneous wear rate of a bearing will be similar functions of the integral over the contact areas of the product of contact pressure and radius from the ball spin axis. A better estimate of wear coefficient should be obtained by relating the average torque, the average wear, the initial torque and the initial wear where the conditions are known. Analysis of tests in sodium at 4000C of high speed steel and Stellite bearings by these methods indicates specific wear rates of the order of 10-15m3/N-m, not unduly out of line with the range of values found in conventional sliding tests

318

Kommunernes rolle i klimaomstilling af byggeriet  

DEFF Research Database (Denmark)

Kapitlet behandler kommunernes rolle i klimaomstilling af byggeriet. Klimaomstilling inden for det kombinerede bolig- og energisystem indebærer transitionsprocesser af socio-tekniske systemer. Kommunernes klimapolitik viser nye veje inden for såvel den lokale governance-struktur som i forhold til omstilling af lokale socio-tekniske systemer. kapitlet undersøger, hvordan kommuner kan udforme klimapolitiske tiltag, som udnytter lokale potentialer, og som kombinerer tilgængelige ressourcer og aktører i fælles visioner og fælles praksis rettet mod at skabe steder for omstilling af de lokale socio-tekniske systemer. Baseret på studier af fire danske kommuner (Sønderborg, Albertslund, Egedal og Næstved) undersøges potentialer og virkemidler, som kommunerne kan benytte i deres rolle som strategiske aktører i udviklingen af sådanne situerede transitionssteder. Kapitlet viser en mangfoldighed i måder, hvorpå specifikke kontekster og specifikke lokale aktørkonstellationer kan koordineres og omdannes til situerede transitionssteder med potentielt fornyende praksisser. Kapitlet afsluttes med at rejse spørgsmål omkring, hvordan sådanne lokale omstillinger kan påvirke det generelle system, og hvilken betydning de lokale initiativer kan have i klimapolitikken

Holm, Jesper; Stauning, Inger

2014-01-01

319

Multi-hundred kilowatt roll ring assembly  

Science.gov (United States)

A program was completed to develop an evaluation unit of a high power rotary transfer device for potential application in a space environment. This device was configured around a Roll Ring concept which performs the same function as a slip ring/brush assembly with a rolling instead of sliding interface. An eight circuit Evaluation Unit (EU) and a portable Test Fixture (TF) were designed and fabricated. The EU was designed to transfer currents to 200 amperes at a potential of as high as 500 volts for an ultimate 100 kW/circuit transfer capability. The EU was evaluated in vacuum at dc transfer currents of 50 to 200 amperes at voltages to 10 volts and at 500 volts at 2 amperes. Power transfer to levels of 2 kW through each of the eight circuits was completed. Power transfer in vacuum at levels and efficiencies not previously achieved was demonstrated. The terminal-to-terminal resistance was measured to be greater than 0.42 milliohms which translates to an efficiency at 100 kW of 99.98 percent. The EU and TF have been delivered to the Lewis Research Center and are being prepared tor testing at increased power levels and for life testing, which will include both dc and ac power.

Jacobson, Peter E.

1985-01-01

320

Modelling the vertical spincasting of large bimettalic rolling mill rolls  

Digital Repository Infrastructure Vision for European Research (DRIVER)

In order to take into account the dynamic effects of molten metal during solidification, a methodology is presented to interface a metal solidification solver with a specifically developped flow dynamics solver.

Studer, Le?o; Detrembleur, Sylvain; Habraken, Anne; Pirotton, Michel; Pascon, Fre?de?ric; Dewals, Benjamin

2008-01-01

 
 
 
 
321

Study of Titanium Alloy Sheet During H-sectioned Rolling Forming Using the Taguchi Method  

International Nuclear Information System (INIS)

This study employs commercial DEFORM three-dimensional finite element code to investigate the plastic deformation behavior of Ti-6Al-4V titanium alloy sheet during the H-sectioned rolling process. The simulations are based on a rigid-plastic model and assume that the upper and lower rolls are rigid bodies and that the temperature rise induced during rolling is sufficiently small that it can be ignored. The effects of the roll profile, the friction factor between the rolls and the titanium alloy, the rolling temperature and the roll radii on the rolling force, the roll torque and the effective strain induced in the rolled product are examined. The Taguchi method is employed to optimize the H-sectioned rolling process parameters. The results confirm the effectiveness of this robust design methodology in optimizing the H-sectioned rolling process parameters for the current Ti-6Al-4V titanium alloy

322

The influence of the shape of grooves on the behavior of internal material discontinuities in continuous S355J2G3 steel strands during rolling  

Directory of Open Access Journals (Sweden)

Full Text Available The article discusses problems related to the influence of rolling processes on the process of closing of internal discontinuities in continuous castings during rolling in shape grooves. Numerical modelling of the process of rolling 160 × 160 mm continuous S355J2G3 steel strands was carried out using the Forge 2008R software program. The experimental studies were conducted in a D150 laboratory rolling mill. Holes simulating material discontinuities were examined. In numerical and experimental studies, in steel samples after rolling in the third rolling stand, the defects were closing in 100 % on average. It was stated that the speed of closing of material discontinuities in feedstock is strongly influenced by the shape of the rolling groove.

H. Dyja

2014-10-01

323

New detection method for rolling element and bearing defects  

Science.gov (United States)

Instrument for detecting defects in rolling elements of bearings is described. Detection depends on rate at which rolling elements impact defect and establishes envelope amplitude of ball resonant frequency. Block diagram of instrument is provided and results obtained in conducting tests are reported.

Burchill, R. F.; Frarey, J. L.

1972-01-01

324

High speed twin roll casters for aluminum alloy strips  

Energy Technology Data Exchange (ETDEWEB)

Two kinds of twin roll caster for aluminum alloys were devised in the present study. Vertical type was adopted. The strip, which was thinner than 3 mm, could be cast at speeds higher than 60 m/min. Aluminum alloy, which freezing zone is very wide like A5182, could be cast using the twin roll caster of the present study at speeds up to 150 m/min. Features of the twin roll casters are as below. Copper rolls were used and lubricant was not used in order to increase the casting speed. Heat transfer between melt and the roll was improved by hydrostatic pressure of the melt. Separating force was very small in order to prevent sticking of the strip to the roll. Low superheat casting was carried out in order to improve microstructure of the strip. A5182 strip, which had equiaxed structure, could be cast. Some heat treatment was tried and tested in order to improve the mechanical property of A5182 strip. A3003 strip was cast by low superheat strip casting. A3003 strip showed thermo-softening resistance. Semisolid strip casting of A356 alloy was tried using a twin roll caster equipped with a cooling slope. Mechanical property, especially elongation, was improved. Result of 180 degrees bending test was improved, too. Semisolid strip casting was useful for high speed roll casting, and the casting speed increased up to 180 m/min. (orig.)

Haga, T. [Osaka Inst. of Tech. (Japan); Suzuki, S. [Technical Univ. Berlin (Germany)

2002-07-01

325

Simulation and optimization of the cold roll-forming process  

Science.gov (United States)

In this paper, the cold roll-forming process of steel was simulated. The FEM model of rollers was built in the LS-DYNA software. There are six stands used in the cold-roll-forming process simulation. The frictions of the tools were determined by the comparison of the cold-roll-forming results and the simulation deformation. Many friction conditions were tested to approach the experimental results of the forming experiments. The blanks were pushed through the rollers in the roll-forming machine. While in the simulation, the rollers were running over the fixed-end blank instead of moving the materials. The resulted motion is the same but the boundary conditions were easier to specify and control. The rolling speeds in the simulation were higher to save the calculation time but still confirm to the experiment results. The simulation results shown the axial and the shear strains were induced during the bending process of sheet metal. The thickness of the sheet metal was varied very slightly during the roll-forming process. The dimension and shape of the cold roll-formed specimens were in good agreement with the experiment results. The Taguchi method was adopted to design an optimum roll flower.

Sheu, Jinn-Jong

2004-06-01

326

Natural circulation characteristics of a marine reactor in rolling motion  

International Nuclear Information System (INIS)

A series of single-phase natural circulation tests in a model reactor with rolling motion was performed, in order to investigate the natural circulation characteristics of a marine reactor in a stormy weather. It was found that the loop flow rate in each leg changes cyclically with the rolling angle due to the inertial force of the rolling motion. As the rolling period becomes shorter, both the amplitude of the loop flow rate oscillations becomes larger and the phase lag between the rolling angle and loop flow rate oscillations becomes larger. On the contrary, the core flow rate does not oscillate, though its value changes with the rolling period. Its change correlates well with both the Reynolds number for rolling motion and the Rayleigh number, and it is considered to be caused by the change of the thermal driving head and pressure loss through the loop. In order to simulate core flow rate change with the rolling period, a simple one-dimensional analytical model was proposed. The calculated results agree well with the experimental results, and its verification is demonstrated. (orig.)

327

Early Detection of Parametric Roll Resonance on Container Ships  

DEFF Research Database (Denmark)

Parametric roll resonance on ships is a nonlinear phenomenon where waves encountered at twice the natural roll frequency can bring the vessel dynamics into a bifurcation mode and lead to extreme values of roll. Recent years have seen several incidents with dramatic damage to container vessels. The roll oscillation, which is subharmonic with respect to the wave excitation, may be completely unexpected and a system for detection of the onset of such resonance could warn the navigators before roll angles reach serious levels. Timely warning could make remedial actions possible, such as change the ship's speed and course, to escape from the bifurcation condition. This paper proposes nonparametric methods to detect the onset of roll resonance and demonstrates their performance. Theoretical conditions for parametric resonance are revisited and are used to develop efficient methods to detect its onset. Spectral and temporal correlations of the square of roll with pitch (or heave) are demonstrated to be of particularinterest as indicators. Properties of the indicators are scrutinized, and a change detector is designed for the Weibull-type of distributions that were observed from a time-domain indicator for phase correlation. Hypothesis testing for resonance is developed using a combination of detectors to obtain robustness. Conditions of forced roll and disturbances in real weather conditions are analyzed and robust detection techniques are suggested. The efficacy of the methodology is shown on experimental data from model tests and on data from a container ship crossing the Atlantic during a storm.

Galeazzi, Roberto; Blanke, Mogens

2013-01-01

328

Microstructure-mechanical property correlation of cryo rolled Zircaloy-4  

Science.gov (United States)

The evolution of microstructure and the mechanical properties of cryo-rolled Zircaloy-4 were both investigated to understand the origin of the alloy's strength processed at a cryogenic temperature. The correlation of dislocation density, grain size and yield stress of the rolled product indicated that an increase in dislocation density due to the suppression of dynamic recovery is the primary source of strengthening.

Sarkar, Apu; Murty, Korukonda L.

2015-01-01

329

Die Rolle des Militärs im politischen System Pakistans  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Der Autor beschreibt in seinem Beitrag die Rolle des Militärs bei der politischen Entwicklung Pakistans seit der Unabhängigkeit 1947. Der mehrfache aktive Einfluss auf Regierungswechsel zeugt von einer aktiven Rolle des Militärs im politischen System des Landes. Seit dem Rücktritt Pervez Musharrafs, ehemaliger Generalstabschef und spätere pakistanischer Militärmachthaber und Präsident, stellt sich erneut die Frage, inwieweit die Armee weiterhin politische Entscheidungen beeinflussen wird.

Kellerhoff, Olaf

2010-01-01

330

Production of normalized steel plate through normalizing rolling; Producao de chapas grossas normalizadas diretamente do calor de laminacao  

Energy Technology Data Exchange (ETDEWEB)

Normalized plates can be got directly from the rolling heat through the use of a normalizing rolling process. In such way, an additional step of the conventional process of production of normalized plates - the normalizing heat treatment - can be suppressed, reducing the manufacturing cost of the product and shortening its production time. This relatively new production route is being used in several steelworks all over the world for many years. This work describes the implementation trials of normalizing rolling at COSIPA`s plate mill, using an alternative process of controlled rolling called recrystallization controlled rolling. The results got with new technique were successful, as it was able to produce plates with properties very similar to the conventionally normalized material, attending the requirements of the DIN 17100 RR 52-3N standard. This is one of many standards that permit the use of this new route of normalized steel plate production. (author) 14 refs., 8 figs., 2 tabs.

Gorni, Antonio Augusto; Cavalcanti, Celso Gomes; Reis, Jackson Soares de Souza; Silveira, Jose Herbert Dolabela da [Companhia Siderurgica Paulista (COSIPA), SP (Brazil)

1997-12-31

331

A study on the wear of silicon nitride in rolling-sliding contact  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The aim of this study is to characterize the wear in silicon nitride rolls undergoing rolling–sliding contact. A rolling contact experiment was proposed and conducted on a twin-disk tribometer. The ceramic rolls were brought into rolling contact with hardened steel disks under water lubrication at a predefined slip ratio. The generated wear on the surface of the rolls was measured and converted into a wear coefficient, which was subsequently implemented in a finite element based simulation ...

Khader, I.; Ku?rten, D.; Kailer, A.

2012-01-01

332

The influence of inhomogeneous rolling on the capacity of aluminium anode foil material  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Several aluminium single crystals were cold rolled under different rolling conditions, characterized by the rolling parameter l/d. The resulting foil was subsequently electrochemically etched and anodized, and the electrical capacity was measured. Inhomogeneously rolled foils showed a higher capacity than did homogeneously rolled foils. This could be attributed to the development of layered structures in the case of inhomogeneous rolling; sharp orientation transitions in these layered str...

Kneynsberg, H. P.; Verbraak, C. A.; Bouwhuis, M. J. Ten

1985-01-01

333

Cold-rolled steel strip X-ray thickness gauge  

International Nuclear Information System (INIS)

This paper introduces a cold-rolled steel strip X-ray thickness gauge. This gauge uses two-detector construction including penetrating ionization chamber and measuring ionization chamber. Standard magazine box is composed of three rotating plates driving by stepper motor, including 13 pieces of standard sample to build up 154 thickness value, obtaining standard sample curve covering thickness range of 0.1 mm to 5 mm. Automation system include Siemens S7-200 PLC as key controlling unit, embedded controlling system for data acquisition and computing, and PC as man-machine interface, and employ Ethernet (TCP/IP) or RS485/232 as communication protocol. Reversing Cold mill AGC closed-loop control operation test demonstrates that the gauge can adapt to the severe production environment, operate stably and reliably, measurement precision can reached to ±0.19%, reproducibility to ±0.09%, and stability to ±0.06%, response time range from 4 ms to 200 ms and be adjustable. So it can meet the high demanding of cold-rolled plate/strip production. (authors)

334

Rolling Textures in Compacts of Copper and Steel  

Science.gov (United States)

This study was undertaken to determine whether differences exist in the rolling textures of materials rolled with and without cladding and whether such differences are affected by bonding the clad and core by hot isostatic pressing (HIP'ing) prior to rolling/ Both steel-clad copper and copper-clad steel were studied, using compacts having nominal volume fractions of core equal to.33 and.50. Unclad core material having the same initial thicnkess as the cores was rolled to similar reductions for comparison with material rolled with cladding. No significant difference in the deformation textures, compared to unclad material, were observed for steel-clad copper. However, for copper-clad steel, a pronounced deformation texture developed in the core at lower total reductions than those required to developed the same degree of texture in unclad material. In these cases, the cladding showed evidence of a shear texture. Prebonding of the compacts by HIP'ing intensified this effect.

Chin, Herbert A. J.; Hartley, Craig S.

1986-11-01

335

Effect of rolling motion on flow in tight lattice  

International Nuclear Information System (INIS)

The flow oscillation and large scale coherent structure in tight lattice in rolling motion is investigated theoretically with URANS. The calculation results are consistent with the experimental data. The rolling motion may have effect on the flow oscillation and coherent structure. The oscillation period in rolling motion is about ten percent bigger than that in steady state. The coherent velocity in rolling motion is a little different from that in steady state. The minimum coherent streamwise velocity is at the channel center, while the maximum coherent streamwise velocity is at the transition region of the channel center and narrow gap. However, the effect of rolling motion on the flow and heat transfer characteristics in tight lattice is limited. (authors)

336

Rolling-contact deformation of MgO single crystals  

Science.gov (United States)

Magnesium oxide single crystals were used as a model bearing material and deformed by rolling contact with a steel ball 0.64 cm in diameter. A dependence of depth of slip on rolling velocity which persisted with increasing numbers of rolling-contact cycles was discovered. The track width, track hardness and dislocation interactions as observed by transmission electron microscopy all increased in a consistent manner with increasing cycles. The rolling-contact state of stress produces a high density of dislocations in a localized zone. Dislocation interaction in this zone produces cleavage-type cracks after a large number of rolling-contact cycles. The orientation of the crystal influences the character of dislocation accumulation.

Dufrane, K. F.; Glaeser, W. A.

1976-01-01

337

Diagnostic capability of 100-mm roll film digitizer system  

International Nuclear Information System (INIS)

The authors recently developed a roll film digitizer system. The sampling pitch is 100 ?m. a scientific image study (Barger phantom, Hawlet chart, and modulation transfer function), receiver operating characteristic (ROC) study, and clinical evaluation were performed. For the ROC study, a chest phantom with simulated nodule and hairline was used. Differences in accuracy between readings of cathode ray tube (CRT) images and roll film images were not statistically significant for hairline and coin lesions, P<.05). As a clinical evaluation, eight radiologists evaluated predetermined radiologic findings on a five-point rating scale compared with original roll film images. Scores for CRT images were equal to those for the original roll film images. In conclusion, CRT images (1,000 x 1,000) were found to be sufficient for diagnostic accuracy of chest images compared with roll film images (100 x 100 mm)

338

Development of rolling texture in copper and brass  

DEFF Research Database (Denmark)

The development of texture in copper and brass (15 pct Zn by weight) rolled at room temperature and in copper rolled at -196degC has been followed by determination of pole figures for various degrees of reduction. The concurrent development in microstructure has been investigated by transmission electron microscopy. For low deformations, the texture in brass, and in copper rolled at -196degC, is the same as the texture in copper rolled at room temperature. The difference in texture does not show until 50% reduction. At the same reduction at which the difference in texture appears, mechanical twinning starts in brass and low-temperature rolled copper. Nevertheless, Wassermann's twinning theory is found to be incompatible with the present results.

Leffers, Torben; Grum-Jensen, A.

1968-01-01

339

High-speed deformation of aluminum by cold rolling  

International Nuclear Information System (INIS)

High-speed deformation of aluminum was carried out by use of a high-speed rolling machine, and the results were compared with those of impact compression. The rolled specimens were electro-polished and observed under an electron microscope. As compared with the microstructures observed in the impact compression specimens, the microstructures observed in the rolled specimens showed almost the same tendency as impact compression for vacancy loop formation, but a different tendency for dislocation cell formations. The difference in the results is explained by the variation in strain rate during deformation in rolling. The results indicate that in high-speed rolling, vacancies and dislocations are produced independently during different periods. Specifically, in the high-strain period, during which dislocations are not generated, deformation proceeds without dislocations

340

Controlling the microstructure of magnesium alloy sheet during rolling  

Energy Technology Data Exchange (ETDEWEB)

A hot rolled magnesium alloy sheet embedded in a steel block was rolled together with 3% thickness reduction at room temperature, 373 K, and 673 K. Tensile twins were observed after the rolling, which could not be found when the magnesium alloy sheet was rolled without the steel block. The twin fraction was the highest at 373 K because of thermal expansion and activating non-basal slip systems at high temperature. Electron back-scattered diffraction analysis and finite element simulations confirmed that the steel block with higher strength played an important role in generating compressive stress along the transverse direction in the magnesium alloy sheet. The compressive stress could increase owing to suppression of thermal expansion in the magnesium alloy sheet at 373 K. The yield stress and the tensile stress became higher in the rolled specimen with the steel block at 373 K than in the specimen without it owing to grain refinement caused by tensile twins.

Kim, Se-Jong, E-mail: ksj1009@kims.re.kr; Yim, Chang Dong; Lee, Young-Seon; Yoon, Jong-Hun; Lee, Jung Hwan

2014-02-24

 
 
 
 
341

Controlling the microstructure of magnesium alloy sheet during rolling  

International Nuclear Information System (INIS)

A hot rolled magnesium alloy sheet embedded in a steel block was rolled together with 3% thickness reduction at room temperature, 373 K, and 673 K. Tensile twins were observed after the rolling, which could not be found when the magnesium alloy sheet was rolled without the steel block. The twin fraction was the highest at 373 K because of thermal expansion and activating non-basal slip systems at high temperature. Electron back-scattered diffraction analysis and finite element simulations confirmed that the steel block with higher strength played an important role in generating compressive stress along the transverse direction in the magnesium alloy sheet. The compressive stress could increase owing to suppression of thermal expansion in the magnesium alloy sheet at 373 K. The yield stress and the tensile stress became higher in the rolled specimen with the steel block at 373 K than in the specimen without it owing to grain refinement caused by tensile twins

342

Slab Analysis of Ring Rolling Assuming Constant Shear Friction  

Science.gov (United States)

In this article, an analytic solution for ring rolling process based on the slab method theory is presented, in which the non-uniformity of the normal and shear stresses across the section of the deforming material throughout the plastic region is considered. The friction factor multiplied by the shear yield strength (? = mk) is used to present friction between the main roll and the ring. The influence of the process parameters such as friction factor, feed speed, main roll rotational speed, and radii of the main roll and mandrel on process outputs is investigated. Complete expressions for the ring rolling pressure, force, and torque are obtained, and the position of neutral point is predicted. Comparison of the analytic results of this model with the experimental results of other investigators and FEM analysis show that they are in good agreement.

Parvizi, A.; Abrinia, K.; Salimi, M.

2011-12-01

343

Rolling Bearing Diagnosis Based on LMD and Neural Network  

Directory of Open Access Journals (Sweden)

Full Text Available Inner ring pitting, the outer indentation and rolling element wear are typical faults of rolling bearing. In order to diagnose these faults rapidly and accurately, the paper proposes a novel diagnosis method of rolling bearing based on the energy characteristics of PF component and neural network by the vibration signal of local mean decomposition(Local mean decomposition, LMD. The vibration signal is decomposed into several PF components by the local mean decomposition, the calculated energy characteristics of the PF component are inputted to the neural network to identify the type of rolling bearing faults. At the same time, the genetic algorithm is introduced to optimize the structure parameters of neural network, which improves diagnostic rate and accuracy of faults. The results show that this method has a higher diagnosis and recognition rate for the typical faults of rolling bearing.

Baoshan Huang

2013-01-01

344

Experimental Study of Critical Heat Flux Under Rolling Condition  

Energy Technology Data Exchange (ETDEWEB)

The most prominent characteristic of a marine reactor is that it is operated during voyage over the ocean. Furthermore the ocean has the most dynamic motion such as rolling, heaving and yawing. The thermalhydraulic behavior of marine reactor can be influenced by rolling (kind of rotation which gives the system a time-dependent inclination together with a centrifugal and a tangential force) and heaving (time-dependent linear vertical gravity acceleration variation) motions, especially. Variation of flow patterns and instability, heat transfer and critical heat flux (CHF) in coolant channel are affected by rolling and heaving motions. Among them, a prediction of the CHF characteristic is an important factor to marine reactor safety and thus its design. The studies of single-phase natural circulation characteristics, two-phase flow instability and heat transfer under rolling motion have been carried out using experimental research and numerical calculation. However, no one has approached CHF under rolling condition. Therefore, experimental study of CHF under rolling condition is needed. To understand the effect of rolling motion on CHF better, tests using a CHF loop mounted on rolling equipment, were performed. During rolling motion, tangential and centrifugal forces imparted are imposed on the coolant channel of marine reactor. It is extremely difficult to draw any plausible flow patterns without relying on the experimental data. Experiment conditions were converted into R-134a condition, which are pressure, inlet subcooling and mass flux as independent variables, corresponding to water condition using fluid-to-fluid scaling. The main purpose of the study is to understand the characteristics of CHF under rolling motion through the experiment

Hwang, Jin Seok; Lee, Yeon Gun; Park, Goon Cherl [Seoul National University, Seoul (Korea, Republic of)

2012-05-15

345

High speed twin roll casting of 6016 aluminium alloy strip  

Directory of Open Access Journals (Sweden)

Full Text Available Purpose: of this paper is to clear the possibility of high speed roll casting of aluminum alloy strip. In the bodyof the automobiles, a sheet of 6016 aluminum alloy is adopted for the outer panel. Therefore, casting of 6016was tried in this study. Characteristics of roll cast 6016 were investigated.Design/methodology/approach: was a high speed twin roll caster. The high speed twin roll caster was designedto overcome the low castability of the twin roll caster.Findings: are as below. 6016 alloy could be cast into the strip continuously at the speed of 60m/min. Thethickness of the strip was 3.4 mm. The microstructure at as-cast and after T4 heat treatment was shown. Themicrostructure was very fine. The mechanical properties were investigated by the tensile test and 180 degreesvending test. The as-cast strip could be cold rolled without homogenization to 1mm. Result of tensile test wastensile strength was 230MPa, 0.2% proof stress was 118MPa and elongation was 33%. 6016 strip of T4 heattreatment could be bent 180 degrees without occurrence of crack at the outer surface or breaking.Research limitations/implications: is the width of the strip was 100 mm. It is necessary to test twin roll casterequipped wide rolls.Practical implications: are as below. The mechanical properties of the roll-cast 6016 were enough for the sheetmetal for the automobile. The low productivity of the twin roll caster could be improved.Originality/value: is that 6016 strip could be cast continuously at speed 60 m/min and this strip had goodmechanical properties.

H. Sakaguchi

2007-01-01

346

Kollektiivlepingu roll töösuhete regulatsioonis pärast uue töölepingu seaduse vastuvõtmist / Kadi Pärnits  

Index Scriptorium Estoniae

Kollektiivlepingu roll töösuhete reguleerimisel Eesti kehtivate seaduste ja uue töölepingu seaduse järgi. Kollektiivlepingu roll Soomes, Taanis, Prantsusmaal, Saksamaal, Ungaris, Tšehhis, Poolas jt. riikides

Pärnits, Kadi, 1965-

2009-01-01

347

Flexible organic tandem solar modules with 6% efficiency: combining roll-to-roll compatible processing with high geometric fill factors  

DEFF Research Database (Denmark)

Organic solar cell technology bears the potential for high photovoltaic performance combined with truly low-cost, high-volume processing. Here we demonstrate organic tandem solar modules on flexible substrates fabricated by fully roll-to-roll compatible processing at temperatures

Spyropoulos, G. D.; Kubis, P.

2014-01-01

348

Material for hot rolling of high boron content austenite stainless steel, and hot rolling method  

International Nuclear Information System (INIS)

A hot rolling material made of a high boron content austenite stainless steel of the present invention comprises a slab made of an austenite stainless steel containing from 0.6 to 2.0% by weight of B and a pad-welded metal layer formed on the side surface of the slab. The pad-welded metal layer has ? ferrite amount of from 3 to 12% by volume, B content up to 0.3% by weight, a thickness of 3mm or greater, and is subjected to hot rolling after heated to a temperature of from 1100 to 1200degC. This can prevent occurrence of peripheral cracking and the material can be industrially manufactured stably at a low cost. (T.M.)

349

Roll-to-roll production of spray coated N-doped carbon nanotube electrodes for supercapacitors  

Science.gov (United States)

Although carbon nanomaterials are being increasingly used in energy storage, there has been a lack of inexpensive, continuous, and scalable synthesis methods. Here, we present a scalable roll-to-roll (R2R) spray coating process for synthesizing randomly oriented multi-walled carbon nanotubes electrodes on Al foils. The coin and jellyroll type supercapacitors comprised such electrodes yield high power densities (˜700 mW/cm3) and energy densities (1 mW h/cm3) on par with Li-ion thin film batteries. These devices exhibit excellent cycle stability with no loss in performance over more than a thousand cycles. Our cost analysis shows that the R2R spray coating process can produce supercapacitors with 10 times the energy density of conventional activated carbon devices at ˜17% lower cost.

Karakaya, Mehmet; Zhu, Jingyi; Raghavendra, Achyut J.; Podila, Ramakrishna; Parler, Samuel G.; Kaplan, James P.; Rao, Apparao M.

2014-12-01

350

Using Light-Induced Thermocleavage in a Roll-to-Roll Process for Polymer Solar Cells  

DEFF Research Database (Denmark)

We report on the use of intense visible light with a narrow spectral distribution matched to the region where the conjugated polymer material absorbs to selectively heat the active material and induce thermocleavage. We show a full roll-to-roll process, leading to complete large-area polymer solar cell modules using light-induced thermocleavage. The process employs full solution processing in air for all five layers in the device and does not employ indium?tin oxide or vacuum processing. The process steps were carefully analyzed using X-ray photoelectron spectroscopy, time-of-flight secondary ion mass spectrometry, attenuated total reflectance infrared, and transmission/reflection UV?vis techniques.

Krebs, Frederik C; Norrman, Kion

2010-01-01

351

Roll-to-roll processed polymer tandem solar cells partially processed from water  

DEFF Research Database (Denmark)

Large area polymer tandem solar cells completely processed using roll-to-roll (R2R) coating and printing techniques are demonstrated. A stable tandem structure was achieved by the use of orthogonal ink solvents for the coating of all layers, including both active layers. Processing solvents included water, alcohols and chlorobenzene. Open-circuit voltages close to the expected sum of sub cell voltages were achieved, while the overall efficiency of the tandem cells was found to be limited by the low yielding back cell, which was processed from water based ink. Many of the challenges associated with upscaling the multilayer tandem cells were identified giving valuable information for future experiments and development.

Larsen-Olsen, Thue Trofod; Andersen, Thomas Rieks

2012-01-01

352

Roll-to-Roll fabrication of large area functional organic materials  

DEFF Research Database (Denmark)

With the prospect of extremely fast manufacture of very low cost devices, organic electronics prepared by thin film processing techniques that are compatible with roll-to-roll (R2R) methods are presently receiving an increasing interest. Several technologies using organic thin films are at the point, where transfer from the laboratory to a more production-oriented environment is within reach. In this review, we aim at giving an overview of some of the R2R-compatible techniques that can be used in such a transfer, as well the current status of R2R application within some of the existing research fields such as organic photovoltaics, organic thin film transistors, light-emitting diodes, polymer electrolyte membrane fuel cells, and electrochromic devices. © 2012 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 000: 000–000, 2012

SØndergaard, Roar R.; Hösel, Markus

2013-01-01

353

Thermoresistive Strain Sensor and Positioning Method for Roll-to-Roll Processes  

Directory of Open Access Journals (Sweden)

Full Text Available This study uses the Joule heating effect-generated temperature difference to monitor in real-time and localize both compressive and tensile strains for the polymer substrates used in the roll-to-roll process. A serpentine gold (Au line was patterned on a polyethylenenaphthalate (PEN substrate to form the strain sensor based on thermoresistive behavior. This strain sensor was then subjected to either current or voltage to induce the Joule heating effect on the Au resistor. An infrared (IR detector was used to monitor the strain-induced temperature difference on the Au and PEN surfaces and the minimal detectable bending radius was 0.9 mm with a gauge factor (GF of 1.46. The proposed design eliminates the judgment ambiguity from conventional resistive strain sensors where resistance is the only physical quantity monitored. This study precisely and successfully indicated the local strain quantitatively and qualitatively with complete simulations and measurements.

Kuan-Hsun Liao

2014-05-01

354

Accumulative roll-bonding: first experience with a twin-roll cast AA8006 alloy  

Energy Technology Data Exchange (ETDEWEB)

An ultra-fine grained (UFG) material was prepared from a twin-roll cast (TRC) Al-Fe-Mn-Si (AA8006) sheet using accumulative roll-bonding (ARB) process. After initial failures to achieve good sheet bonding, five cycles of ARB at 200 deg. C were successfully performed. Scanning electron microscopy (Electron Backscatter Diffraction) and transmission electron microscopy (TEM) were used for the characterization of subgrain and grain structures of ARB processed samples. The strength of ARB sheets was evaluated by microhardness measurements. Very fine grain structure (0.4-0.8 {mu}m) with large disorientation was observed after two cycles of ARB. In two samples, areas with extremely fine grains 0.1-0.3 {mu}m in diameter were found. The hardness of the alloy increased from 28 to 60 HV1 after the first two cycles, but during subsequent ARB processing it rose only very slightly.

Karlik, M.; Homola, P.; Slamova, M

2004-09-22

355

Rheological effects in roll coating of paints  

Scientific Electronic Library Online (English)

Full Text Available SciELO Argentina | Language: English Abstract in english the aim of this work is the study of the problems that arise during roll coating application of paints on steel sheets. We put in evidence the particular effects due to the non-Newtonian properties of these fluids. At speeds above a certain critical value, the flow of paint through the applicator su [...] ffers a hydrodynamical instability called ribbing, which generates a patterned interface on the film applied. Threshold of instability as well as waveform of the pattern is function of rheological properties of paints as well as surface tension. Thixotropy of paints as well as shear-thinning behaviour has been determined for several industrial paints used in the steel industry, and correlated with levelling performance after application.

F., Varela López; M., Rosen.

2002-07-01

356

Periodically fighting shake, rattle and roll  

CERN Document Server

How easy is it to suppress shake, rattle and roll in a long bridge or a skyscraper? Most practical structures are designed so that long wave resonance vibrations can be avoided. However, there are recent examples, such as the Millennium Bridge in London or the Volga Bridge in Volgograd, which show that unexpected external forces may result in large scale unwanted shake and rattle. Full scale alteration of a bridge (or a skyscraper) would not be considered as an acceptable option, unless the structure has collapsed. Can we fix this by examining a representative part of the structure only and making small lightweight changes? We will do it here and illustrate an idea linking the engineering analysis to elastic waveguides.

Brun, M; Jones, I S

2011-01-01

357

G_2 and the "Rolling Distribution"  

CERN Document Server

Associated to the problem of rolling one surface along another there is a five-manifold M with a rank two distribution. If the two surfaces are spheres then M is the product of the rotation group SO_3 with the two-sphere and its distribution enjoys an obvious symmetry group; the product of two SO_3's, one for each sphere. But if the ratio of radii of the spheres is 1:3 and if the distribution is lifted to the universal cover S^3 \\times S^2 of M, then the symmetry group becomes much larger: the split real form of the Lie group G_2. This fact goes back to Cartan in a sense, and can be found in a paper by Bryant and Hsu. We prove this fact through two explicit constructions, relying on the theory of roots and weights for the Lie algebra of G_2, and on its 7-dimensional representation.

Bor, G; Bor, Gil; Montgomery, Richard

2006-01-01

358

Rocking and rolling: A can that appears to rock might actually roll  

Science.gov (United States)

A beer bottle or soda can on a table, when slightly tipped and released, falls to an upright position and then rocks up to a somewhat opposite tilt. Superficially this rocking motion involves a collision when the flat circular base of the container slaps the table before rocking up to the opposite tilt. A keen eye notices that the after-slap rising tilt is not generally just diametrically opposite the initial tilt but is veered to one side or the other. Cushman and Duistermaat [Regular Chaotic Dyn. 11, 31 (2006)] recently noticed such veering when a flat disk with rolling boundary conditions is dropped nearly flat. Here, we generalize these rolling disk results to arbitrary axi-symmetric bodies and to frictionless sliding. More specifically, we study motions that almost but do not quite involve a face-down collision of the round container’s bottom with the tabletop. These motions involve a sudden rapid motion of the contact point around the circular base. Surprisingly, similar to the rolling disk, the net angle of motion of this contact point is nearly independent of initial conditions. This angle of turn depends simply on the geometry and mass distribution but not on the moment of inertia about the symmetry axis. We derive simple asymptotic formulas for this “angle of turn” of the contact point and check the result with numerics and with simple experiments. For tall containers (height much bigger than radius) the angle of turn is just over ? and the sudden rolling motion superficially appears as a nearly symmetric collision leading to leaning on an almost diametrically opposite point on the bottom rim.

Srinivasan, Manoj; Ruina, Andy

2008-12-01

359

Função de afilamento para Virola surinamensis (Roll.) Warb Tapering function for Virola surinamensis (Roll.) Warb  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Este estudo foi conduzido com o propósito de gerar equação de afilamento para Virola surinamensis (Roll.) Warb, que está entre as espécies mais exportadas pela indústria madeireira do estuário amazônico. Foram testados os modelos de Kozak (1969), Baldwin (1991), Demaerschalk (1972) e Garay (1979). Todos esses modelos estimaram o diâmetro comercial com precisão, porém os três primeiros resultaram em inconsistência ao estimar a altura comercial. O modelo de Garay foi selecionado e ...

Helio Garcia Leite; João Ricardo Vasconcellos Gama; Jovane Pereira da Cruz; Agostinho Lopes de Souza

2006-01-01

360

Autonomous Supervision and Control of Parametric Roll Resonance  

DEFF Research Database (Denmark)

When ships sail in longitudinal waves, and the encounter frequency and wave length satisfy certain conditions, passage of wave crest and wave trough along the hull continuously amplifies the roll motion at half the frequency of encounter. This gives the onset of a resonance condition. The phenomenon can induce a rapid increase in roll motion that can reach 40 degrees or more. Recent incidents have shown that modern container ships and some fishing vessels are particularly prone to this due to their hull shape. Such incidents can result in damages counting to millions of USD. Theoretically, the resonance behaviour is well understood and it can be reproduced by quasi-periodic changes in parameters of nonlinear differential equations that describe ship motion. Practically, the challenge is whether detection and stabilization can be achieved in time to avoid damage. The research in this thesis has therefore two objectives. The first is to develop methods for detection of the inception of parametric roll resonance. The second is to develop control strategies to stabilize the motion after parametric roll has started. Stabilisation of parametric roll resonance points to two possible courses of action. One is a direct stabilisation through an increase of damping in roll, which increases the threshold that triggers the resonant motion. A second is to obtain a change in wave encounter frequency by means of changes in ship forward speed and/or heading. As direct stabilisation, this thesis considers the increase of roll damping by using fin stabilisers, which are controlled using integrator backstepping methods. As indirect stabilisation, a shift in the encounter frequency is considered by varying the ship forward speed. The speed controller is designed using nonlinear Lyapunov methods. The two control strategies are then combined to stabilise parametric roll resonance within few roll cycles. Limitations on the maximum stabilisable roll angle are analysed and linked to the ii slew rate saturation and hydrodynamic stall characteristics of the fin stabilisers. The study on maximum stabilisable roll angle leads to the requirements for early detection. Two novel detectors are proposed, which work within a shorttime prediction horizon, and issue early warnings of parametric roll inception within few roll cycles from its onset. The main idea behind these detection schemes is that of exploiting the link between the second harmonic of roll angle and the first harmonic of heave or pitch motions. A nonlinear energy flow indicator, which measures the transfer of energy from the first harmonic of heave or pitch into the second harmonic of roll, is at the core of the first detector. The second detector relies on a driving signal that carries information about the phase correlation between either pitch or heave and roll. A generalised likelihood ratio test is designed to detect a change in distribution of the driving signal. The detectors are validated against experimental data of tests of a 1:45 scale model of a container ship. The validation shows excellent performance in terms of time to detect and false-alarm rate for both the proposed detectors. The detectors are the main contribution of this research. The thesis also offers a contribution regarding modeling. A 3 degree-offreedom nonlinear model in heave-pitch-roll of a container ship suitable for parametric roll resonance study is proposed. The model, which has been developed in collaboration with other researchers, provides a benchmark for the study and simulation of parametric roll over a large range of ship speeds and sea states. The results of this research have been published in articles enclosed in this dissertation and in an international patent application.

Galeazzi, Roberto

2010-01-01

 
 
 
 
361

Progress in cold roll bonding of metals  

International Nuclear Information System (INIS)

Layered composite materials have become an increasingly interesting topic in industrial development. Cold roll bonding (CRB), as a solid phase method of bonding same or different metals by rolling at room temperature, has been widely used in manufacturing large layered composite sheets and foils. In this paper, we provide a brief overview of a technology using layered composite materials produced by CRB and discuss the suitability of this technology in the fabrication of layered composite materials. The effects of process parameters on bonding, mainly including process and surface preparation conditions, have been analyzed. Bonding between two sheets can be realized when deformation reduction reaches a threshold value. However, it is essential to remove surface contamination layers to produce a satisfactory bond in CRB. It has been suggested that the degreasing and then scratch brushing of surfaces create a strong bonding between the layers. Bonding mechanisms, in which the film theory is expressed as the major mechanism in CRB, as well as bonding theoretical models, have also been reviewed. It has also been showed that it is easy for fcc structure metals to bond compared with bcc and hcp structure metals. In addition, hardness on bonding same metals plays an important part in CRB. Applications of composites produced by CRB in industrial fields are briefly reviewed and possible developments of CRB in the future are also described. Corrections were made to the abstractbed. Corrections were made to the abstract and conclusion of this article on 18 June 2008. The corrected electronic version is identical to the print version. (topical review)

362

Antireflective surface patterned by rolling mask lithography  

Science.gov (United States)

A growing number of commercial products such as displays, solar panels, light emitting diodes (LEDs and OLEDs), automotive and architectural glass are driving demand for glass with high performance surfaces that offer anti-reflective, self-cleaning, and other advanced functions. State-of-the-art coatings do not meet the desired performance characteristics or cannot be applied over large areas in a cost-effective manner. "Rolling Mask Lithography" (RML™) enables highresolution lithographic nano-patterning over large-areas at low-cost and high-throughput. RML is a photolithographic process performed using ultraviolet (UV) illumination transmitted through a soft cylindrical mask as it rolls across a substrate. Subsequent transfer of photoresist patterns into the substrate is achieved using an etching process, which creates a nanostructured surface. The current generation exposure tool is capable of patterning one-meter long substrates with a width of 300 mm. High-throughput and low-cost are achieved using continuous exposure of the resist by the cylindrical photomask. Here, we report on significant improvements in the application of RML™ to fabricate anti-reflective surfaces. Briefly, an optical surface can be made antireflective by "texturing" it with a nano-scale pattern to reduce the discontinuity in the index of refraction between the air and the bulk optical material. An array of cones, similar to the structure of a moth's eye, performs this way. Substrates are patterned using RML™ and etched to produce an array of cones with an aspect ratio of 3:1, which decreases the reflectivity below 0.1%.

Seitz, Oliver; Geddes, Joseph B.; Aryal, Mukti; Perez, Joseph; Wassei, Jonathan; McMackin, Ian; Kobrin, Boris

2014-03-01

363

Synthesis and Characterization of Hot-Roll and Cold-Roll Byproduct-Derived Strontium Hard Ferrites  

Directory of Open Access Journals (Sweden)

Full Text Available Problem statement: Ceramic permanent magnets or more commonly known as strontium hexagonal ferrites have been widely used in permanent magnetic materials as they provide high remanence, high coercivity, relatively high energy product and good chemical stability. In this study, we treated factory byproduct from hot-roll and cold-roll steel industry was used as raw material in synthesis of strontium hexagonal hard ferrites. Approach: X-Ray Diffraction (XRD was employed to confirm the formation of strontium hard ferrite compound. Vibrating Sample Magnetometer (VSM was used to analyze the magnetic properties of samples prepared. Results: The magnetic properties, namely remanence and coercivity of factory byproduct-derived strontium hard ferrites were compared. The cold-roll-derived strontium hard ferrite showed higher remanence in this study. Conclusion: This implied that cold-roll byproduct was a better candidate to replace hematite in preparation of strontium hard ferrites compared to hot-roll byproduct.

H. S. Woon

2009-01-01

364

Influence of chemistry and hot rolling conditions on high permeability non-grain oriented silicon steel  

International Nuclear Information System (INIS)

This paper discusses the influence of chemical composition on the final electromagnetic properties in higher permeability material. Furthermore, the effect of the hot rolling practice and the end of austenite transformation temperature range on the hot band microstructure is described. The magnetic polarization J 5000 better than 1.7 T, using hot rolling conditions 40 mm transfer bar thickness, finish mill entry temperature 1000 deg. C, and finishing temperature 800-840 deg. C and after decarburization heat treatment and grain growth treatment, was obtained

365

Mechanical spectroscopy of rolling oil thin films on cold-rolled steel sheets  

Science.gov (United States)

Fine traces of lubricating oil can be discovered in the form of fine debris left on the surface of cold-rolled steel sheets. High resolution mechanical spectroscopy is a sensitive technique for detecting such extremely fine oil traces. It is shown that a characteristic mechanical loss spectrum occurs in the low temperature range (from 180K up to 280K) only in the two following cases, namely (i) if traces of the rolling oil are left on the surface of sheets and (ii) if the clean sheets are covered with a thin film of the rolling oil (or any other natural or mineral oil). It is clearly demonstrated that similar mechanical spectra induced by the presence of oil can be observed in the sub-resonant mechanical spectroscopy if the oil film is deposited on a very soft cellulose neutral substrate. Therefore the behaviour of the oil alone can be obtained with a high resolution. It will be demonstrated that it is possible to assign the mechanical loss phenomena to the steel sheet (like the Snoek-Koster effect above 500K) and oil separately. In particular, it is shown that the low temperature relaxation phenomena do not originate from a specific interaction of the steel surface with oil, as frequently reported in the literature.

Magalas, L. B.; Etienne, S.

2009-09-01

366

Microstructure and plastic anisotropy in rolled Al-Mg alloys  

Energy Technology Data Exchange (ETDEWEB)

The directionality of tensile behaviour in cold rolled AA5005 ({proportional_to}1% Mg) and AA5182 ({proportional_to} 5%Mg) alloys has been investigated. Both materials initially had a 'cube' texture, that in the AA5005 being significantly stronger. At rolling strains up to 0.5, the cube texture remained dominant in both alloys. In the AA5005 there was a marked dependence of mechanical behaviour on the degree of prior rolling strain and on the direction of the tensile axis relative to the rolling direction. Part of the directionality was due to crystallographic texture effects, notably the contribution to work hardening- and so elongation- from the change in preferred orientation occurring in tension at 45 to the rolling direction. There was also a significant difference in plastic behaviour between tension at 0 and 90 to the rolling direction, caused by the directionality in deformation substructure generated during the rolling which led to characteristic strain path change effects. Static recovery was found to affect the work hardening and ductility of the samples, and this is thought to be due to substructural condensation. The overall behaviour of AA5005 was quite similar to that reported for commercial purity AA1200. However, in AA5182, such strain path effects were not observed for the pre-strains investigated. This is due to the lack of a well developed aligned substructure in this material caused by the effect of magnesium solute on dynamic recovery. (orig.)

Eardley, E.S.; Humphreys, F.J.; Bate, P.S. [Manchester Materials Science Centre, Manchester (United Kingdom); Soulet, A. [SMS, Ecole Nationale Superieure des Mines, Saint Etienne (France); Court, S.A. [Alcan International Banbury Lab., Bandbury (United Kingdom)

2003-07-01

367

Determining asymmetry of roll-over shapes in prosthetic walking  

Directory of Open Access Journals (Sweden)

Full Text Available How does the inherent asymmetry of the locomotor system in people with lower-limb amputation affect the ankle-foot roll-over shape of prosthetic walking? In a single-case design, we evaluated the walking patterns of six people with lower-limb amputation (3 transtibial and 3 transfemoral and three matched nondisabled controls. We analyzed the walking patterns in terms of roll-over characteristics and spatial and temporal factors. We determined the level of asymmetry by roll-over shape comparison (root-mean-square distance as well as differences in radius of curvature. In addition, we calculated ratios to determine spatial and temporal asymmetries and described different aspects of asymmetry of roll-over shapes. All participants showed some level of asymmetry in roll-over shape, even the nondisabled controls. Furthermore, we found good intralimb reproducibility for the group as a whole. With respect to spatial and temporal factors, the participants with transtibial amputation had a quite symmetrical gait pattern, while the gait in the participants with transfemoral amputation was more asymmetrical. The individual ankle-foot roll-over shapes provide additional insight into the marked individual adjustments occurring during the stance phase of the nondisabled limb. The two methods we present are suitable for determining asymmetry of roll-over shapes; both methods should be used complementarily.

Carolin Curtze, MSc

2011-12-01

368

Effect of heating and deformation conditions on the depth of surface defects in alloyed steel rolling  

International Nuclear Information System (INIS)

The effect of heating and deformation conditions on the depth change of artificial defects in the 50 KhFA alloyed steel rolling on the 850 blooming and 450 section mill was studied. Quite a definite regularity in the arrangement of defects (cracks and hairlines) along the circumference of the round steel bar and obvious relation with the defect distribution on the bloom faces are established. Oxidation is shown to diminish defect depth while ingot and billet heating especially on the faces under direct firing. Blooms should be placed in the furnace with 90 deg canting in relation to the faces position while ingot heating. Round rolling must be performed with one or several 45 deg strip cantings. The defect depth for the ingots to be rolled without chipping is set up

369

Analysis of slug flow unit model in rolling vertical tube  

International Nuclear Information System (INIS)

The slug flow unit model in rolling vertical tube was analyzed in this paper, by setting up some equations, such as mass conversation equations and the necessary conditions for the existence of slug flow. Based on this slug flow unit model, the correlation for calculating average void fraction of slug flow in rolling tube was presented, and the calculations were agreed well with experimental data. So, this slug flow unit model could be used as the basis for further analyzing the flow property of slug flow under rolling condition. (authors)

370

Dynamic geometry of a rotating paper machine roll  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The research is initiated by the findings that the coating variation of light weight coated LWC paper is in synchronization with a backing roll of a coating station. The frequency of the largest peak in the quality variation spectrum corresponds to the oval geometry of a backing roll, but no such a phenomenon has been measured in a roll shop. It was realized that the cause of the research problem could be the change in the geometry as a function of running speed. First, a theoretical stu...

Juhanko, Jari

2011-01-01

371

Perehdyttämiskansio : Case: Rosk'n Roll Oy Ab  

Digital Repository Infrastructure Vision for European Research (DRIVER)

New Employee Orientation Portfolio Case: Rosk’n Roll Ltd. The goal of this thesis was to create a comprehensive new employee orientation portfolio for Rosk’n Roll Ltd. The purpose of the portfolio was to develop an established standard in new employee orientation in the company. This would guarantee a consistent orientation for all employees. Rosk’n Roll Ltd. wished that the portfolio would assist the new employee in his/her adjustment to the work community as well as to his/her own...

Palin, Elina; Pesonen, Jenni

2009-01-01

372

Optimization of Contact Point Trajectory for a Spherical Rolling Robot  

Science.gov (United States)

Recently, various types of spherical robots that can roll and move on the ground have been developed. We are now developing a spherical robot that can roll and, in addition, rotate around the vertical axis simultaneously. By using the added degree of freedom, the attitude of the robot can be changed arbitrarily even when the robot rolls along a specified path on the ground. This paper proposes an optimal trajectory planning method for the robot that moves along a straight line on the ground. The trajectory that connects an initial attitude and a final attitude is obtained by finding the optimal contact point trajectory on a spherical surface.

Urakubo, Takateru; Maekawa, Satoshi; Ueda, Tetsuya; Tamaki, Hisashi

373

Cold rolling of hexagonal rods of VT16 alloy  

International Nuclear Information System (INIS)

The technology of a cold rolling of the rods made of VT16 alloy is exemplified by the production of a 6 mm hexagonal section. The rolling of the hexagonal section has been performed in five passes by means of four-, two-, and three-roll grooves. The sizing procedure adopted makes it possible to obtain the hexahedron of a regular geometric form with a high dimensional accuracy and a good surface quality. Analysis of form variation reveals that such a procedure favours a uniform section deformation, the first two passes resulting in a heavy reduction of the piece along the diagonals of the hexahedron

374

FEM analysis of hollow hub forming in rolling extrusion process  

Directory of Open Access Journals (Sweden)

Full Text Available In this paper are presented the results of numerical calculations of rolling extrusion process of a hollow hub. As the flanges manufacturing at both sides of the product is required, in the analyzed process of rolling extrusion, a rear bumper was implemented as additional tool limiting axial metal flow. Numerical calculations of the hub forming process were conducted basing on finite element method, applying software Deform3D and Simufact in conditions of three dimensional state of strain. The obtained satisfactory results show that it is possible to conduct the further research works of experimental character, with the application of a modernized aggregate for the rolling extrusion process PO-2.

J. Bartnicki

2014-10-01

375

Study of Hydroplaning Risk on Rolling and Sliding Passenger Car :  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Hydroplaning speed is known to vary over a range of tire slipping conditions from free rolling to completely skidding. An attempt has been made to simulate two extreme conditions of hydroplaning i.e. when the tire is completely rolling (0% slip) and a completely locked tire (100% slip). ASTM standard smooth tire moving over the plane pavement surface is considered in the model. The analyses showed that the hydroplaning risk associated with the locked tire is more than the rolling tire. The mo...

Kumar, S. S.; Anupam, K.; Scarpas, A.; Kasbergen, C.

2012-01-01

376

Graphite inclusions in surface layers of cold rolls  

International Nuclear Information System (INIS)

In a surface layer of cold rolls of steels types 90KhMF and 60Kh2SMF graphite inclusions have been revealed with variations in content of 0.08 to 0.30%. Graphite has been found to form in the process of preliminary heat treatment of rolls. The reasous are proposed for the role of graphite in formation of fracture zone in rolls on operation. The possibility is discussed to avoid graphitization by way of changing preliminary heat treatment conditions

377

Rotational instability of plastic deformation of beryllium under cold rolling  

International Nuclear Information System (INIS)

The change of pole features of (0002) planes during cold rolling of sheets of commercially pure hot-rolled beryllium, as well as the change in (1013) line half width in case of strain degree increase are studied. It is assumed that the appearance and development of mutually-reoriented regions of crystal lattice are realized as a result of creation of a certain strained state in the deformation focus in the process of cold rolling. Periodically repeated ratational releases result in the decrease in the density of chaotically distributed dislocations, the level of internal microstrains, which permits to deform beryllium plastically by more than 60 % without destruction

378

Access to the Commonwealth electoral roll for medical research.  

Science.gov (United States)

In the 2010-11 financial 2013, there was a dramatic reduction in the approvals granted by the Australian Electoral Commission for access to samples of the adult population derived from the electoral roll for the purposes of public health research. Much time and effort has been expended in making applications without success. Researchers refused access to electoral roll samples must rely on sampling methods that are not as robust and that may produce less reliable data. We outline a set of recommendations that, if adopted, will result in a fairer system for obtaining access to the electoral roll for public health research. PMID:23879514

Loff, Bebe; Campbell, Elissa A; Glass, Deborah C; Kelsall, Helen L; Slegers, Claudia; Zion, Deborah R; Brown, Ngaire J; Fritschi, Lin

2013-07-22

379

Influence of 10 % Cold Rolling Reduction on Ageing Behaviour of Hot Rolled Al-Cu-Si-Mn-Mg Alloy  

Science.gov (United States)

In the current study, the effect of 10 % cold rolling on the different ageing phenomena of Al-Cu-Si-Mn-Mg alloy was investigated. Both hot rolled and cold rolled alloys were subjected to both natural and artificial ageing processes. Hardness was measured to understand the change in the mechanical property of the alloy before and after rolling and also during ageing processes. From microscopy, it was evident that the cold rolling and subsequent ageing provided the alloy with a structure in which CuAl2 precipitates were uniformly distributed. The alloy exhibited the peak hardness value of 92 VHN after 2 days of natural ageing, whereas the cold deformed (10 %) alloy exhibited the higher peak hardness value of 139 VHN after 3 days of natural ageing. Peak hardness of the alloy reached 94 VHN, when hot rolled alloy was subjected to ageing at 250 °C for 1 h, whereas 10 % cold rolling followed by ageing (100 °C, 15 min) demonstrated accelerated and elevated hardening. The ageing behaviours thus obtained permit the alloy to provide a range of desirable combinations of strength and ductility for high strength weight saving applications.

Ghosh, S. K.

2014-10-01

380

Rolling element bearing diagnostics—A tutorial  

Science.gov (United States)

This tutorial is intended to guide the reader in the diagnostic analysis of acceleration signals from rolling element bearings, in particular in the presence of strong masking signals from other machine components such as gears. Rather than being a review of all the current literature on bearing diagnostics, its purpose is to explain the background for a very powerful procedure which is successful in the majority of cases. The latter contention is illustrated by the application to a number of very different case histories, from very low speed to very high speed machines. The specific characteristics of rolling element bearing signals are explained in great detail, in particular the fact that they are not periodic, but stochastic, a fact which allows them to be separated from deterministic signals such as from gears. They can be modelled as cyclostationary for some purposes, but are in fact not strictly cyclostationary (at least for localised defects) so the term pseudo-cyclostationary has been coined. An appendix on cyclostationarity is included. A number of techniques are described for the separation, of which the discrete/random separation (DRS) method is usually most efficient. This sometimes requires the effects of small speed fluctuations to be removed in advance, which can be achieved by order tracking, and so this topic is also amplified in an appendix. Signals from localised faults in bearings are impulsive, at least at the source, so techniques are described to identify the frequency bands in which this impulsivity is most marked, using spectral kurtosis. For very high speed bearings, the impulse responses elicited by the sharp impacts in the bearings may have a comparable length to their separation, and the minimum entropy deconvolution technique may be found useful to remove the smearing effects of the (unknown) transmission path. The final diagnosis is based on "envelope analysis" of the optimally filtered signal, but despite the fact that this technique has been used for 40 years in analogue form, the advantages of more recent digital implementations are explained.

Randall, Robert B.; Antoni, Jérôme

2011-02-01

 
 
 
 
381

Dynamics of Entangled Polymeric Fluids in Two-roll Mill studied via Dynamic Light Scattering and Two-color flow Birefringence. II. Transient flow  

Digital Repository Infrastructure Vision for European Research (DRIVER)

We present an extensive experimental study of birefringence and velocity-gradient components for a series of high molecular weight, flexible, entangled polystyrene solutions subjected to transient start-up flows in a co-rotating two-mill to several Weissenberg numbers. The time-dependent changes in the polymer microstructure, as measured by a two-color flow birefringence technique, is shown to be very distinctly coupled with the transient response of the corresponding veloci...

Sanyal, Subrata; Yavich, Dmitry; Leal, L. Gary

2000-01-01

382

Semi-industrial simulation of hot rolling and controlled cooling of Mn-Al TRIP steel sheets  

Directory of Open Access Journals (Sweden)

Full Text Available Purpose: The aim of the work is a semi-industrial physical simulation of thermomechanical rolling and controlled cooling of advanced high-strength steels with increased Mn and Al content.Design/methodology/approach: Four steels of various Mn and Nb concentration were thermomechanically rolled in 3 and 5 passes using a modern LPS line for physical simulation of hot rolling at a semi-industrial scale. The hot deformation course is fully automated as well as controlled cooling applied directly after finishing rolling. Temperature-time and force-energetic parameters of hot rolling were continuously registered and assessed.Findings: The applied line consisting of two-high reversing mill, roller tables with heating panels, cooling devices and controlling-recording systems reflects industrial hot strip rolling parameters sufficiently. Reduction values and temperature-time regimes are similar to those used in industrial practice whereas strain rate is limited to about 10 s-1 what requires taking into account during comparison. All the steels investigated have high total pressure forces due to the high total content of alloying elements. The critical factor making it possible to obtain high-quality sheet samples with a thickness up to 3.3 mm is applying isothermal heating panels which decrease a cooling rate of thin sheets.Research limitations/implications: The real complete simulation of hot strip rolling requires extension of a used line with a further module for simulation of continuous finishing rolling stages. The work is in progress.Practical implications: The results can be successfully utilized in industrial hot rolling and controlled cooling practices after necessary modifications.Originality/value: The efficient semi-industrial physical simulation of hot strip thermomechanical rolling of some new model AHSS grades containing increased Mn and Al content as well as Nb microadditions was presented.

A. Grajcar

2013-03-01

383

78 FR 10501 - Airworthiness Directives; Rolls-Royce Deutschland Ltd & Co KG Turbofan Engines  

Science.gov (United States)

...Directives; Rolls-Royce Deutschland Ltd & Co KG Turbofan Engines AGENCY: Federal Aviation...for all Rolls-Royce Deutschland Ltd & Co KG (RRD) BR700-710A1-10 and BR700- 710A2-20...2013-03-17 Rolls-Royce Deutschland Ltd & Co KG (Formerly Rolls-Royce Deutschland...

2013-02-14

384

77 FR 16917 - Airworthiness Directives; Rolls-Royce Deutschland Ltd & Co KG Turbofan Engines  

Science.gov (United States)

...Directives; Rolls-Royce Deutschland Ltd & Co KG Turbofan Engines AGENCY: Federal Aviation...contact Rolls-Royce Deutschland Ltd & Co KG, Eschenweg 11, Dahlewitz, 15827 Blankenfelde...2012-06-17 Rolls-Royce Deutschland Ltd & Co KG (Formerly Rolls-Royce plc, Derby,...

2012-03-23

385

77 FR 39156 - Airworthiness Directives; Rolls-Royce Deutschland Ltd & Co KG (RRD) Turbofan Engines  

Science.gov (United States)

...Directives; Rolls-Royce Deutschland Ltd & Co KG (RRD) Turbofan Engines AGENCY: Federal...2009-07-01 R1 Rolls-Royce Deutschland Ltd & Co KG (formerly BMW Rolls-Royce GmbH, formerly...applies to Rolls-Royce Deutschland Ltd & Co KG BR700- 715A1-30,...

2012-07-02

386

78 FR 17080 - Airworthiness Directives; Rolls-Royce Deutschland Ltd & Co KG Turbofan Engines  

Science.gov (United States)

...Directives; Rolls-Royce Deutschland Ltd & Co KG Turbofan Engines AGENCY: Federal Aviation...certain Rolls-Royce Deutschland Ltd & Co KG (RRD) BR700-710 series turbofan engines...2013-05-13 Rolls-Royce Deutschland Ltd & Co KG (Formerly Rolls-Royce Deutschland...

2013-03-20

387

77 FR 9869 - Airworthiness Directives; Rolls-Royce Deutschland Ltd & Co KG (RRD) Turbofan Engines  

Science.gov (United States)

...Directives; Rolls-Royce Deutschland Ltd & Co KG (RRD) Turbofan Engines AGENCY: Federal...2009): Rolls-Royce Deutschland Ltd & Co KG (formerly BMW Rolls-Royce GmbH, formerly...applies to Rolls-Royce Deutschland Ltd & Co KG BR700- 715A1-30,...

2012-02-21

388

78 FR 17082 - Airworthiness Directives; Rolls-Royce Deutschland Ltd & Co KG Turbojet Engines  

Science.gov (United States)

...Directives; Rolls-Royce Deutschland Ltd & Co KG Turbojet Engines AGENCY: Federal Aviation...certain Rolls-Royce Deutschland Ltd & Co KG (RRD) Spey 511-8 turbojet engines...2013-05-20 Rolls-Royce Deutschland Ltd & Co KG (formerly Rolls-Royce Deutschland...

2013-03-20

389

78 FR 17079 - Airworthiness Directives; Rolls-Royce Deutschland Ltd & Co KG Turbofan Engines  

Science.gov (United States)

...Directives; Rolls-Royce Deutschland Ltd & Co KG Turbofan Engines AGENCY: Federal Aviation...certain Rolls-Royce Deutschland Ltd & Co KG (RRD) models Tay 620-15 and Tay 650-15...2013-06-01 Rolls-Royce Deutschland Ltd & Co KG (RRD) (formerly Rolls-Royce...

2013-03-20

390

Development of polymers for large scale roll-to-roll processing of polymer solar cells  

DEFF Research Database (Denmark)

Development of polymers for large scale roll-to-roll processing of polymer solar cells Conjugated polymers potential to both absorb light and transport current as well as the perspective of low cost and large scale production has made these kinds of material attractive in solar cell research. The research field of polymer solar cells (PSCs) is rapidly progressing along three lines: Improvement of efficiency and stability together with the introduction of large scale production methods. All three lines are explored in this work. The thesis describes low band gap polymers and why these are needed. Polymer of this type display broader absorption resulting in better overlap with the solar spectrum and potentially higher current density. Synthesis, characterization and device performance of three series of polymers illustrating how the absorption spectrum of polymers can be manipulated synthetically and how this affects the PSC parameters are presented. It is generally found that it is possible to syntheticallycontrol the absorption spectrum of conjugated polymer systems. One way to alter the spectrum is by incorporating alternating donor-acceptor motifs, resulting in an additional optical absorption band, the charge transfer (CT) band. A second approach is to introduce fused donor systems. A third method is to use several different monomer units in the polymerization hereby creating semirandom polymers with multiple chromophores. By changing the fed ratio of the monomers the absorption spectrum can effectively be tuned and a significant broadening of the absorption spectrum is obtained. A focus in this thesis is stabilization of the active layer morphology and the photochemical stability of its components. In terms of stability PSC degrades under illumination and the operational lifetime are generally limited. A fundamental understanding of the degradation of PSCs allows one to develop improved materials that can increase their lifetime. Synthesis and characterization of polymer materials for improved stability in PSCs is presented. Stabilization of the active layer was accomplished by incorporating different types of crosslinking functionalities into the polymer TQ1. Cross-linking was achieved by UV-light illumination to give solvent resistant films and reduced phase separation and growth of PCBM crystallites in polymer:PCBM films. This study showed that cross-linking can improve morphological stability but that it has little influence on the operational stability of the device. The photochemical stability of a wide range of materials relevant to PSC is presented and compared. General rules relative to the polymer structure–stability relationship are proposed and can be used as a guideline for further development of PSCs. One of the main advantages of PSCs is that they can be produced using printing techniques which allows for large scale roll-to-roll (R2R) production. A laboratory roll coater that enables solution processing of five layers on ITO-free flexible substrates using slot-die coating and flexographic printing is presented. As little as one ml of active material solution is needed to produce more than a hundred devices. This laboratory scale approach to PSCs was found to be directly scalable to the large scale R2R equipment making it suitable as a test platform for polymer development. PSC devices based on PDTSTTz-4 and PCBM were produced using the laboratory roll coater and through optimerization of the processing parameters a PCE of 2.95 % at ambient condition. This efficiency is among the highest obtained on flexible ITO-free substrates using slot-die coating.

Carlé, Jon Eggert

2013-01-01

391

Dengue vaccine roll-out: getting ahead of the game  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Dengue vaccines are currently being tested in clinical trials but public health specialists are already working on delivery strategies for a rapid roll-out to the people who need them most. Gozde Zorlu and Fiona Fleck report.

2011-01-01

392

Geometric conditions for the existence of an intrinsic rolling  

CERN Document Server

We give a complete answer to the question of when two curves in two different Riemannian manifolds can be seen as trajectories of rolling one manifold on the other without twisting or slipping. We show that up to technical hypotheses, a rolling along these curves exists if and only if the geodesic curvatures of each curve coincide. By using the anti-developments of the curves, which we claim can seen of as a generalization of the geodesic curvatures, we are able to extend the result to arbitrary absolutely continuous curves. For a manifold of constant sectional curvature rolling on itself, two such curves can only differ by an isometry. In the case of surfaces, we give conditions for when loops in the manifolds lift to loops in the configuration space of the rolling.

Molina, Mauricio Godoy

2011-01-01

393

Rock'n'roll, tankid ja vabadus Endlas / Ülle Hallik  

Index Scriptorium Estoniae

Tšehhi päritolu briti näitekirjaniku Tom Stoppardi "Rock'n' roll" Endla teatris, üks lavastajatest on psühholoog ja koolitaja Heiti Pakk. Näidendi tegevus toimub Tšehhimaal aastatel 1968-1990. Esietendus 7. märtsil

Hallik, Ülle, 1963-

2008-01-01

394

Improvments in heating regimes and the quality of rolled strips  

International Nuclear Information System (INIS)

The possibility of enhancing the quality of rolled strips of steels and alloys of different structure classes (12Kh18N10T, 50N, 79NM, etc.) has been studied, the improvement in the quality being effected through varying the preheating modes of slabs. The specific defects corresponding to the steels under study are considered. A mechanism of the generation of defects, which is connected with the peculiar features of preheating slabs and ingots for rolling, is shown. A dearease in the temperature of the preheating of slabs for rolling may be used as an efficient means for obviating the defects. The power parameters of the rolling process have been calculated according to the results of plastometric tests, and the preheating modes have been rendered more precise

395

Põllumajandus-kaubanduskoja roll euroliitu astumisel / Ester Tuiksoo  

Index Scriptorium Estoniae

Autor leiab, et suurima tootjate ja töötlejate ringkondi ühendava organisatsioonina on EPKK roll ja ülesanded EL-i kontekstis pidevalt muutuvad ning ka organisatsioon muutub ja areneb vastavalt aja vajadustele.

Tuiksoo, Ester, 1965-

2003-01-01

396

Prediction of Parametric Roll Resonance by Multilayer Perceptron Neural Network  

DEFF Research Database (Denmark)

Parametric roll resonance is a ship stability related phenomenon that generates sudden large amplitude oscillations up to 30-40 degrees of roll. This can cause severe damage, and it can put the crew in serious danger. The need for a parametric rolling real time prediction system has been acknowledged in the last few years. This work proposes a prediction system based on a multilayer perceptron (MP) neural network. The training and testing of the MP network is accomplished by feeding it with simulated data of a three degrees-of-freedom nonlinear model of a fishing vessel. The neural network is shown to be capable of forecasting the ship’s roll motion in realistic scenarios.

Míguez González, M; López Peña, F.

2011-01-01

397

21 CFR 136.110 - Bread, rolls, and buns.  

Science.gov (United States)

...prescribed for milk bread by § 136.130... (11) Nonwheat flours, nonwheat meals, nonwheat grits, wheat and nonwheat starches...dextrinized wheat flour, or any combination...a preservative in bread, rolls, or...

2010-04-01

398

21 CFR 136.115 - Enriched bread, rolls, and buns.  

Science.gov (United States)

...wheat germ or partly defatted wheat germ, but the total quantity thereof, including any wheat germ or partly defatted wheat germ in any enriched flour used, shall not be more...the food is “enriched bread”, “enriched rolls”,...

2010-04-01

399

Adaptive methods, rolling contact, and nonclassical friction laws  

Science.gov (United States)

Results and methods on three different areas of contemporary research are outlined. These include adaptive methods, the rolling contact problem for finite deformation of a hyperelastic or viscoelastic cylinder, and non-classical friction laws for modeling dynamic friction phenomena.

Oden, J. T.

1989-01-01

400

Correlating microstructure and texture in cold-rolled Ta ingot  

International Nuclear Information System (INIS)

An analysis of tantalum ingot cold-rolled and annealed under different conditions reveals several correlations between the microstructure, developed textures and thermomechanical processing parameters. For example, the hardness of rolled sheet is not significantly affected by the amount of reduction prior to the final anneal, while the final grain size decreases with an increasing number of intermediate annealing steps. Four classes of texture are found in the cold-rolled tantalum, but the finger-grained classes can only be produced via a 70 percent reduction in thickness prior to the final anneal. Although ample dislocation debris is produced by the rolling operation, clearly defined line dislocations and dislocations networks are absent, indicating that full recrystallization is not achieved in the finished sheets. A large concentration of ledge dislocations at the grain boundary regions is considered an important contributor to the good formability of tantalum

 
 
 
 
401

Second order perturbations during inflation beyond slow-roll  

International Nuclear Information System (INIS)

We numerically calculate the evolution of second order cosmological perturbations for an inflationary scalar field without resorting to the slow-roll approximation or assuming large scales. In contrast to previous approaches we therefore use the full non-slow-roll source term for the second order Klein-Gordon equation which is valid on all scales. The numerical results are consistent with the ones obtained previously where slow-roll is a good approximation. We investigate the effect of localised features in the scalar field potential which break slow-roll for some portion of the evolution. The numerical package solving the second order Klein-Gordon equation has been released under an open source license and is available for download

402

Numerical simulations supporting the process design of ring rolling processes  

Science.gov (United States)

In conventional Finite Element Analysis (FEA) of radial-axial ring rolling (RAR) the motions of all tools are usually defined prior to simulation in the preprocessing step. However, the real process holds up to 8 degrees of freedom (DOF) that are controlled by industrial control systems according to actual sensor values and preselected control strategies. Since the histories of the motions are unknown before the experiment and are dependent on sensor data, the conventional FEA cannot represent the process before experiment. In order to enable the usage of FEA in the process design stage, this approach integrates the industrially applied control algorithms of the real process including all relevant sensors and actuators into the FE model of ring rolling. Additionally, the process design of a novel process 'the axial profiling', in which a profiled roll is used for rolling axially profiled rings, is supported by FEA. Using this approach suitable control strategies can be tested in virtual environment before processing.

Jenkouk, V.; Hirt, G.; Seitz, J.

2013-05-01

403

Second Order Perturbations During Inflation Beyond Slow-roll  

CERN Document Server

We numerically calculate the evolution of second order cosmological perturbations for an inflationary scalar field without resorting to the slow-roll approximation or assuming large scales. In contrast to previous approaches we therefore use the full non-slow-roll source term for the second order Klein-Gordon equation which is valid on all scales. The numerical results are consistent with the ones obtained previously where slow-roll is a good approximation. We investigate the effect of localised features in the scalar field potential which break slow-roll for some portion of the evolution. The numerical package solving the second order Klein-Gordon equation has been released under an open source license and is available for download.

Huston, Ian

2011-01-01

404

Roll-to-roll nanopatterning using jet and flash imprint lithography  

Science.gov (United States)

The ability to pattern materials at the nanoscale can enable a variety of applications ranging from high density data storage, displays, photonic devices and CMOS integrated circuits to emerging applications in the biomedical and energy sectors. These applications require varying levels of pattern control, short and long range order, and have varying cost tolerances. Extremely large area R2R manufacturing on flexible substrates is ubiquitous for applications such as paper and plastic processing. It combines the benefits of high speed and inexpensive substrates to deliver a commodity product at low cost. The challenge is to extend this approach to the realm of nanopatterning and realize similar benefits. The cost of manufacturing is typically driven by speed (or throughput), tool complexity, cost of consumables (materials used, mold or master cost, etc.), substrate cost, and the downstream processing required (annealing, deposition, etching, etc.). In order to achieve low cost nanopatterning, it is imperative to move towards high speed imprinting, less complex tools, near zero waste of consumables and low cost substrates. The Jet and Flash Imprint Lithography (J-FILTM) process uses drop dispensing of UV curable resists to assist high resolution patterning for subsequent dry etch pattern transfer. The technology is actively being used to develop solutions for memory markets including Flash memory and patterned media for hard disk drives. In this paper we address the key challenges for roll based nanopatterning by introducing a novel concept: Ink Jet based Roll-to-Roll Nanopatterning. To address this challenge, we have introduced a J-FIL based demonstrator product, the LithoFlex 100. Topics that are discussed in the paper include tool design and process performance. In addition, we have used the LithoFlex 100 to fabricate high performance wire grid polarizers on flexible polycarbonate (PC) films. Transmission of better than 80% and extinction ratios on the order of 4500 have been achieved.

Ahn, Sean; Ganapathisubramanian, Maha; Miller, Mike; Yang, Jack; Choi, Jin; Xu, Frank; Resnick, Douglas J.; Sreenivasan, S. V.

2012-03-01

405

Noble Logic for Preventing Scratch on Roll-to-Roll Printed Layers in Noncontacting Transportation  

Science.gov (United States)

The use of roll-to-roll (R2R) printed electronics is a relatively new method of mass producing flexible electronic devices while keeping production costs down. The geometrical qualities of a printed pattern, such as surface roughness and uniformity, could deteriorate. Moreover, the geometric qualities of a printed layer affect the functional qualities of a printed electronic device directly. Therefore, the functional qualities (conductivity and mobility) of a multilayer electronic device could deteriorate in the presence of a scratch defect on the printed layer. In general, a scratch on a printed pattern on a flexible substrate is induced by contact between the rolls and printed pattern in R2R printing systems. To prevent such contact, one of the best solutions is to use an air flotation unit. However, a scratch defect could be induced even though an air flotation process is used to minimize contact, because the flotation height of a moving web is affected by web tension. In this paper, we discuss an analytical model of an air-floated moving substrate. For the noncontacting transfer of a moving web without a scratch defect, a mathematical tension model has been developed by considering an induced strain due to aerodynamic forces and verified by numerical and experimental studies. Additionally, the correlation between the flotation height of an air-floated moving web and speed compensation used to control the tension are investigated. The analysis shows that tension fluctuations can cause the substrate to touch the air-flotation subsystem, which is installed to prevent contact, resulting in defects such as scratches on the printed layer. On the basis of the proposed model, a logic is developed to minimize scratch defects on R2R printed layers in noncontacting transportation. Through a guideline based on this logic, the scratched area density on R2R printed layers can be reduced by approximately 70%.

Lee, Changwoo; Kang, Hyunkyoo; Kim, Hojoon; Shin, Keehyun

2010-05-01

406

Development of a paper based roll-to-roll nanoimprinting machine  

Science.gov (United States)

Nanoimprint lithography (NIL) has been developed and studied since 1995. It is a technique where micro- or nanoscale patterns are transferred to soft materials such as polymer through pressing a stamp with certain patterns into this materials and then solidifying it by cooling at lower temperature or curing under ultra violet excitement. High Cost and low throughput of batch mode nanoimprint lithography (NIL) processes are limiting its wide range of applications in meeting industry manufacturing requirements. The roll-to-roll (R2R) nanoimprinting technology is emerged as a solution to this issue. This thesis study presents the design, build and test of an innovative R2R T-NIL process machine for nanofabrication and MEMS fabrication applications, which consists of individual modules of heating, inking, pressuring, and rotational speed control. The system utilizes PDMS as mold material, PMMA as imprinting material, and paper as substrate material. In order to achieve a uniform pressure on PMMA during imprinting process, an innovative air pressure device (APD) was developed and integrated with R2R machine. The APD replaces the conventional 2-roll line contact pressure approach and can cover one third of the surface of the imprinting roller with a uniform pressure (1-3 psi). During the imprinting experiment, a mixture of PMMA (20w %) and 2-Ethoxyethyl acetate is applied on the paper substrate by an inking roller using capillary force and an IR heater is used for pre-heating and drying of polymer layers before it is fed into the imprinting module. Two 500-Watt cartridge heaters are installed on the roller and provide the heat to raise the PMMA film temperature during the imprinting.

Son, Byungwook

407

An improved rolled strip pulse forming line  

Science.gov (United States)

The rolled strip pulse forming line (RSPFL) has advantages of compactness, portability, and long pulse achievability which could well meet the requirements of industrial application of the pulse power technology. In this paper, an improved RSPFL with an additional insulator between the grounded conductors is investigated numerically and experimentally. Results demonstrate that the jitter on the flat-top of the output voltage waveform is reduced to 3.8% due to the improved structure. Theoretical analysis shows that the electromagnetic coupling between the conductors of the RSPFL strongly influences the output voltage waveform. Therefore, the new structure was designed to minimize the detrimental effect of the electromagnetic coupling. Simulation results show that the electromagnetic coupling can be efficiently reduced in the improved RSPFL. Experimental results illustrate that the improved RSPFL, with dimensions and weight of ? 290 × 250 mm and 16 kg, when used as a simple pulse forming line, could generate a well shaped quasi-square pulse with output power of hundreds of MW and pulse duration of 250 ns. Importantly, the improved RSPFL was successfully used as a Blumlein pulse forming line, and a 10.8 kV, 260 ns quasi-square pulse was obtained on a 2 ? dummy load. Experiments show reasonable agreement with numerical analysis.

Li, Song; Qian, Bao-Liang; Yang, Han-Wu; Gao, Jing-Ming; Liu, Zhao-Xi

2013-06-01

408

Elastohydrodynamics of tensioned web roll coating process  

Science.gov (United States)

Coating process is an important step in the manufacturing of different products, such as paper, adhesive and magnetic tapes, photographic films, and many other. The tensioned web roll coating is one the several methods used by different industries. It relies on the elastohydrodynamic action between the fluid and the tensioned substrate for transferring and applying the liquid. The main advantage of this method is its ability to apply very thin liquid layers with less sensitivity to mechanical tolerance at relative small cost. Despite its industrial application, theoretical analysis and fundamental understanding of the process are limited. This work analyses this elastohydrodynamic action by solving the differential equations that govern the liquid flow, described by the Navier-Stokes equation, and the web deformation, modelled by the cylindrical shell approximation. The goal is to determine the operating conditions at which the process is two dimensional and defect free. The equations are discretized by the Galerkin/finite-element method. The resulting non-linear system of equations is solved by Newton's method coupled with pseudo-arc-length continuation in order to obtain solutions around turning points. The theoretical results are used to construct an operating window of the process that is in agreement with limited experimental data.

Carvalho, M. S.

2003-02-01

409

A mechanism for ramified rolling circle amplification  

Directory of Open Access Journals (Sweden)

Full Text Available Abstract Background Amplification of single-stranded DNA circles has wide utility for a variety of applications. The two-primer ramified rolling circle amplification (RAM reaction provides exponential DNA amplification under isothermal conditions, creating a regular laddered series of double-stranded DNA products. However, the molecular mechanism of the RAM reaction remains unexplained. Results A RAM reaction model predicts exponential accumulation of a double-stranded DNA product size series, and product-size ratios, that are consistent with observed RAM reaction products. The mechanism involves generation of a series of increasing size intermediate templates; those templates produce RAM products and recursively generate smaller intermediate templates. The model allows prediction of the number of rounds of circular template replication. Real-time RAM reaction data are consistent with the model. Analysis of RAM reaction products shows exponential growth limitation consistent with the model's predictions. Conclusions The model provides a rationale for the observed products of the RAM reaction, and the molecular yield among those products. Experimental results are consistent with the model.

Smith James H

2010-12-01

410

Communication using eye roll reflective signalling  

Science.gov (United States)

Body reflections in the ultraviolet (UV) are a common occurrence in nature. Despite the abundance of such signals and the presence of UV cones in the retinas of many vertebrates, the function of UV cones in the majority of taxa remains unclear. Here, we report on an unusual communication system in the razorback sucker, Xyrauchen texanus, that involves flash signals produced by quick eye rolls. Behavioural experiments and field observations indicate that this form of communication is used to signal territorial presence between males. The flash signal shows highest contrast in the UV region of fhe visual spectrum (??max???380 nm), corresponding to the maximum wavelength of absorption of the UV cone mechanism in suckers. Furthermore, these cones are restricted to the dorsal retina of the animal and the upwelling light background is such that their relative sensitivity would be enhanced by chromatic adaptation of the other cone mechanisms. Thus, the UV cones in the sucker have optimal characteristics (both in terms of absorbance and retinal topography) to constitute the main detectors of the flash signal. Our findings provide the first ecological evidence for restricted distribution of UV cones in the retina of a vertebrate. ?? 2007 The Royal Society.

Flamarique, I.N.; Mueller, G.A.; Cheng, C.L.; Figiel, C.R.

2007-01-01

411

Roll Forming of AHSS: Numerical Simulation and Investigation of Effects of Main Process Parameters on Quality  

Science.gov (United States)

The roll forming process is one of the main processes of producing straight profiles in many industrial sectors. The introduction of Advanced High Strength Steels (AHSS), such as the DP and TRIP-series, into the production of roll-formed profiles has emerged new challenges. The combination of a higher yield strength with a lower total elongation of AHSS, brings new challenges to the roll forming process. In the current study, the numerical simulation of a V-section profile has been implemented. The effect of the main process parameters, such as the roll forming line velocity, rolls inter-distance, roll gap and rolls diameter on quality characteristics is investigated.

Salonitis, Konstantinos; Paralikas, John; Chryssolouris, George

412

Wheel rolling constraints and slip in mobile robots  

Energy Technology Data Exchange (ETDEWEB)

It is widely accepted that dead-reckoning based on the rolling with no-slip condition on the wheels is not a reliable method to ascertain the position and orientation of a mobile robot for any reasonable distance. The authors establish that wheel slip is inevitable under the dynamic model of motion using classical results on the accessibility and controllability in nonlinear control theory and an analytical model of rolling of two linearly elastic bodies.

Shekhar, S. [Oak Ridge National Lab., TN (United States). Robotics and Process Systems Div.

1996-06-01

413

Wheel rolling constraints and slip in mobile robots  

Energy Technology Data Exchange (ETDEWEB)

It is widely accepted that dead reckoning based on the rolling with no slip condition on wheels is not a reliable method to ascertain the position and orientation of a mobile robot for any reasonable distance. We establish that wheel slip is inevitable under the dynamic model of motion using classical results on the accessibility and controllability in nonlinear control theory and an analytical model of rolling of two linearly elastic bodies.

Shekhar, S.

1997-03-01

414

Micro Crack of Aluminum Sheet During Cold Rolling  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The micro crack of aluminum sheet during cold rolling lubricated with emulsions is investigated. Experi-ments show that micro cracks occur after cold rolling process and this is attributed to various parameters, for instance, the thin oxide film formed at the sheet surface. The micro crack spacing thus becomes an important parameter which deserves more concerns. The aspect ratio of these micro cracks is then analyzed theoreti-cally, which takes into consideration of the oxide fracture process...

Chaohui Zhang; Sisi Liu; Chenhui Zhang

2011-01-01

415

TOPICAL REVIEW Progress in cold roll bonding of metals  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Layered composite materials have become an increasingly interesting topic in industrial development. Cold roll bonding (CRB), as a solid phase method of bonding same or different metals by rolling at room temperature, has been widely used in manufacturing large layered composite sheets and foils. In this paper, we provide a brief overview of a technology using layered composite materials produced by CRB and discuss the suitability of this technology in the fabrication of layered composite mat...

Long Li, Kotobu Nagai And Fuxing Yin

2008-01-01

416

High speed twin roll casting of 6016 strip  

Directory of Open Access Journals (Sweden)

Full Text Available Purpose: of this paper is to clear the possibility of high speed roll casting of thin aluminum alloy strip. 6016aluminum alloy is used for sheet metal of the automobile. Therefore, casting of 6016 was tried in this study.Castability and characteristics of roll cast 6016 strip were investigated.Design/methodology/approach: was a high speed twin roll caster. The high speed twin roll caster was designedto overcome the low castability of the twin roll caster.Findings: are as below. The 6016 could be cast at speed of 60 m/min. The thickness of the 6016 was 3 mm.The microstructure at as-cast and after T6 heat treatment was shown. The microstructure was very fine by theeffect of the rapid solidification. The mechanical properties were investigated by the tension test and 180 degreesbending test. The as-cast strip could be cold rolled down to 1 mm without homogenization. The result of tensiontest (gage length 50mm of T4 strip was as below, tensile stress was 242 MPa, proof stress was 123 MPa andelongation was 26%. There was no crack at the outer surface of 180-degree-bent strip until contact. This showsthe strip endure the hem forming.Research limitations/implications: is the width of the strip was 100 mm. The test using a large scale twin rollcaster must be operated.Practical implications: are as below. The mechanical properties of the roll-cast 6016 were enough for the sheetmetal for the automobile. The low productivity of the twin roll caster could be improved, and economy 6016strip was able to produce.Originality/value: is that 6016 strip could be cast at speed 60 m/min and this strip had good mechanicalproperties.

T. Haga

2006-08-01

417

Continuous roll casting of aluminium alloys – casting parameters analysis  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The main goal of the paper was to present the influence of casting parameters on casting conditions and interference of casting parameters on the final strip characteristics such as constant strip thickness, surface quality and roughness of aluminum alloys sheet 6,30 to 6,50 mm thick. The study shows that casting speed, roll force and roll gap should have the greatest influence on the final strip thickness, and that the examined parameters agree well with the theoretical standpoints.

Krstic? Vukelja, E.; Duplanc?ic?, I.; Lela, B.

2010-01-01

418

Wheel rolling constraints and slip in mobile robots  

Energy Technology Data Exchange (ETDEWEB)

It is widely accepted that dead reckoning based on the rolling with no slip condition on wheels is not a reliable method to ascertain the position and orientation of a mobile robot for any reasonable distance. The author establishes that wheel slip is inevitable under the dynamic model of motion using classical results on the accessibility and controllability in nonlinear control theory and an analytical model of rolling of two linearly elastic bodies.

Shekhar, S.

1997-03-01

419

A theory of sovereign debt roll-over crisis  

Digital Repository Infrastructure Vision for European Research (DRIVER)

In this paper, we attempt to provide theoretical investigation to debt roll-over crisis in government bond market. By using the global game techniques, we analyse coordination problem in debt auction. The approach in this paper allows us to have insight on the relation between occurence of soverign debt roll-over crisis and the fundamentals of economy which is not clearly explained in preceding works. This paper also makes it clear how the amount of debt for refinancing affects occurrence of ...

Hattori, Masazumi

2004-01-01

420

Tool condition analysis and monitoring in cold rolling process  

Digital Repository Infrastructure Vision for European Research (DRIVER)

This research is about a costly problem in the automotive industry due to tool fracture during the splines cold rolling of steel shafts. The objective is to study the cause of this failure and propose solutions that can be implemented in the workshop.The writing starts with a brief introduction of the companies involved in shafts production and problem solving. It introduces the cold rolling process and its advantages on splines manufacturing, and it goes through relevant material and process...

El Siblani, Ali

2011-01-01

 
 
 
 
421

Microstructural Investigation of Co-rolled Nanocrystalline Stainless Steel Sheets  

Digital Repository Infrastructure Vision for European Research (DRIVER)

It is possible to produce a nanocrystalline, multilayered composite structure with enhanced mechanical properties by assembling three 316L surface nanostructured stainless steel plates by roll bonding. The Surface Mechanical Attrition Treatment (SMAT) was first used to generate nanocrystalline layers on the elementary plates so that their mechanical properties were improved. They were then assembled through co-rolling. A composite structure of nanocrystalline layers of high strength alternati...

Retraint, Delphine; Quadir, Zakaria; Xu, Wanqiang; Waltz, Laurent; Ferry, Michael

2011-01-01

422

Validation of hot ring rolling industrial process 3D simulation  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Ring rolling is a hot forming process used in the production of railway tyres, anti friction bearing races and different ring shaped work pieces for automotive energy production and aerospace applications. The advantages of ring rolling process include short production time, uniform quality, closed tolerances, good material quality and considerable saving in material cost. Despite the benefits some problems still exist according to a correct selection of the process parameters. Due to the nat...

Giorleo, Luca; Giardini, Claudio; Ceretti, Elisabetta

2013-01-01

423

On the asperity point load mechanism for rolling contact fatigue  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Rolling contact fatigue is a damage process that may arise in mechanical applications with repeated rolling contacts. Some examples are: gears; cams; bearings; rail/wheel contacts. The resulting damage is often visible with the naked eye as millimeter sized surface craters. The surface craters are here denoted spalls and the gear contact served as a case study. The work focused on the asperity point load mechanism for initiation of spalls. It was found that the stresses at asperity level may ...

Dahlberg, Johan

2007-01-01

424

Evaluation of the Frictional Characteristics of Rolling Emulsions  

Digital Repository Infrastructure Vision for European Research (DRIVER)

A series of ring compression tests were carried out in samples machined from hot- rolled steel slabs to determine the frictional characteristics of various emulsions used for lubrication in cold rolling of steel strip; additional tests were conducted without lubrication or using polytetrafluorethylene (PTFE) tape. The material was tested at different velocities in a servo-hydraulic computer driven testing machine. The friction factor (m) was evaluated from the dimensional change of the ring s...

Fa, Vicente Espinoza-cant U.; Guerrero-mata, Martha P.; Lozano, Tom U. E. S.; Rafael Col\\u00E1s

2008-01-01

425

Effect of grain shape on the texture evolution during cold rolling of Al-Mg alloys  

International Nuclear Information System (INIS)

Research highlights: ? Texture evolution during rolling is quantified by the JMAK equation. ? Grain shape affects the rate of formation or disappearance of texture components. ? Elongated grains results in a faster evolution of texture in straight-rolling. - Abstract: The hot bands of continuous cast AA 5754 and high-Fe AA 5754 aluminum alloys exhibited elongated grains in the rolling direction after recrystallization annealing. The annealed hot bands were cold rolled to different reductions along the original rolling direction and transverse direction, respectively. The effect of grain shape on texture evolution was investigated by X-ray diffraction. It was found that straight-rolling resulted in a higher rate of disappearance of the r-cube + cube component and a slightly higher rate of formation of the ? fiber component than cross-rolling. The elongated grains in the rolling direction were easier to rotate from initial orientations to the ? fiber in straight-rolling than in cross-rolling.

426

Effect of grain shape on the texture evolution during cold rolling of Al-Mg alloys  

Energy Technology Data Exchange (ETDEWEB)

Research highlights: > Texture evolution during rolling is quantified by the JMAK equation. > Grain shape affects the rate of formation or disappearance of texture components. > Elongated grains results in a faster evolution of texture in straight-rolling. - Abstract: The hot bands of continuous cast AA 5754 and high-Fe AA 5754 aluminum alloys exhibited elongated grains in the rolling direction after recrystallization annealing. The annealed hot bands were cold rolled to different reductions along the original rolling direction and transverse direction, respectively. The effect of grain shape on texture evolution was investigated by X-ray diffraction. It was found that straight-rolling resulted in a higher rate of disappearance of the r-cube + cube component and a slightly higher rate of formation of the {beta} fiber component than cross-rolling. The elongated grains in the rolling direction were easier to rotate from initial orientations to the {beta} fiber in straight-rolling than in cross-rolling.

Yuan, H.; Wang, Q.F.; Zhang, J.W. [Key Laboratory of Metastable Materials Science and Technology, College of Materials Science and Engineering, Yanshan University, No. 438 Hebei Avenue, Qinhuangdao, Hebei 066004 (China); Liu, W.C., E-mail: wcliu@ysu.edu.cn [Key Laboratory of Metastable Materials Science and Technology, College of Materials Science and Engineering, Yanshan University, No. 438 Hebei Avenue, Qinhuangdao, Hebei 066004 (China); Gao, Y.K. [Beijing Institute of Aeronautical Materials, Beijing 100095 (China)

2011-01-21

427

Computer-aided analysis and design of the shape rolling process for producing turbine engine airfoils  

Science.gov (United States)

Mild steel (AISI 1018) was selected as model cold rolling material and Ti-6A1-4V and Inconel 718 were selected as typical hot rolling and cold rolling alloys, respectively. The flow stress and workability of these alloys were characterized and friction factor at the roll/workpiece interface was determined at their respective working conditions by conducting ring tests. Computer-aided mathematical models for predicting metal flow and stresses, and for simulating the shape rolling process were developed. These models utilized the upper bound and the slab methods of analysis, and were capable of predicting the lateral spread, roll separating force, roll torque, and local stresses, strains and strain rates. This computer-aided design system was also capable of simulating the actual rolling process, and thereby designing the roll pass schedule in rolling of an airfoil or a similar shape.

Lahoti, G. D.; Akgerman, N.; Altan, T.

1978-01-01

428

Evaluation for lubricant by simulation testing machine developed newly in hot rolling; Aratani kaihatsushita netsukan atsuengata junkatsusei hyoka shikenki ni yoru atsuen`yu no junkatsusei hyoka  

Energy Technology Data Exchange (ETDEWEB)

Recently, rolls made of high speed steel (HSS) which are superior to wear and abrasion resistance are used in many hot rolling mills. However some troubles are occurred due to by the use of the HSS roll. To solve these problems, new lubricants are developed and the lubricities of them are estimated by using the two-disk testing machine or the pin-on-disk testing machine. But the evaluation obtained by these testing machines are different from one of the actual rolling processing. In order to evaluate the lubricity of lubricant in hot rolling, the simulation testing machine in the laboratory is modified from one for cold rolling. The evaluation performance of the simulation testing machine is investigated into using the SPHC workpiece strip having dimensions of a width of 20 mm and a thickness of 2 mm at a hot rolling temperature of 1,030 degree C. From the experimental results, the lubricity of lubricant in hot rolling can be evaluated by the coefficient of friction measured. The effect of the additive on the coefficient of friction can be also confirmed. The obtained results are as follows; (1) When the mineral oil and one with oiliness additives are used as lubricants, the coefficient of friction increases rapidly with increasing rolling distance. (2) When the oils with the extreme-pressure additives are used, the coefficient of friction is steady over a rolling distance of 1,000 mm. (author)

Aoki, K.; Sato, T.; Azushima, A. [Yokohama National University, Yokohama (Japan). Faculty of Engineering

1999-06-01

429

Rolling in the Higgs Model and Elliptic Functions  

CERN Document Server

Asymptotic methods in nonlinear dynamics are used usually to improve perturbation theory results in the oscillations regime. However, for some problems of nonlinear dynamics, particularly in the case of Higgs (Duffing) equation and the Friedmann cosmological equations, not only small oscillations regime is of interest but also the regime of rolling (claiming), more precisely the rolling from a top (claiming to the top). In the Friedman cosmology, where the slow rolling regime is often used, the rolling from a top (not necessary slow) is of interest too. In the present work a method for approximate solution to the Higgs equation in the rolling regime is presented. It is shown that in order to improve perturbation theory in the rolling regime it turns out to be effective not to use an expansion in trigonometric functions as it is done in case of small oscillations but use expansions in hyperbolic functions instead. This regime is investigated using the representation of the solution in terms of elliptic functio...

Arefeva, I Ya; Volovich, I V

2012-01-01

430

Stresses inside a roll in case of higher belt tension ?????????? ? ?????? ??? ?????????????? ????????? ?????  

Directory of Open Access Journals (Sweden)

Full Text Available The author considers the problem of stresses arising in the roll in case of higher tension value in the roll-forming belt. It is noticed, that if some force is applied to the loose end of the roll-forming belt, outer layers are set in motion — they stretch and slightly slip along lower layers. The slipping surface gradually shifts to the center of the roll and either reaches the surface of the core, or stops at some distance from it. The penetration depth depends on the initial tension, the intensity of the applied force and the belt material properties. Thus, the two zones are formed — the outer zone where the belt slides, and the inner zone, where no relative motion of layers is demonstrated, but where layers compress under a higher pressure produced on the zone boundaries. At some values of influential parameters, the third zone appears near the core area, which is also a slip zone. Stress redistribution occurs here both due to the relative shift of layers, and to the higher pressure produced by the outer part of the roll. The analytical solution to the problem is found assuming that the formed roll is a homogeneous isotropic cylinder.??????????? ?????? ??????????? ??????????, ??????????? ? ?????????????? ?????? ??? ?????????????? ????????? ?????, ?????????? ?????. ????????, ??? ???? ? ?????????? ????? ?????, ?????????? ?????, ????????? ????????? ????, ?? ???????? ???? ???????? ? ???????? ?, ???????????, ????????? ?????????????? ?? ??????????? ?????. ??????????? ??????????????? ?????????? ????????? ? ?????? ?????? ? ???? ????????? ??????????? ??????????, ???? ??????????????? ?? ????????? ???????? ?? ????. ??????? ????????????? ??????? ?? ????????? ??????????, ???????? ??????????? ???? ? ??????? ????????? ?????. ????? ???????, ?????????? ??? ????: ????????, ? ??????? ?????????? ?????????? ?????, ? ??????????, ? ??????? ?????????????? ???????? ????? ?? ??????????, ?? ???? ??????????? ??? ????????? ??????????????? ???????? ?? ???????? ????. ??? ????????? ????????? ???????????? ?????????? ?????? ??????????? ?????????? ????????? ?????? ????, ???????, ??? ? ????????, ???????? ????? ??????????. ????? ????????????????? ?????????? ?????????? ??? ?? ???? ?????????????? ???????? ?????, ??? ? ?? ???? ??????????????? ???????? ?? ??????? ???????? ????? ??????. ???????? ????????????? ??????? ???????????? ?????? ? ?????????????, ??? ?????????????? ????? ???????????? ????? ?????????? ?????????? ???????.

Antonov Viktor Ivanovich

2013-09-01

431

Prediction of mechanical properties of hot rolled steel products  

Directory of Open Access Journals (Sweden)

Full Text Available Purpose: Model for prediction of mechanical properties of rolled steel products after final cooling from exitrolling temperature is one of the basic component of any software for complex computer simulation of rollingtechnologies. Theoretical background and implementation of such software tool is described.Design/methodology/approach: After calculation of cooling curves by any technology dependent Shell thesoftware tool MECHP can be called to predict CCT Diagram from current chemical composition of steel andinitial properties of deformed austenite first than structure shares (percentage of ferrite, pearlite, bainite andmartensite resulting from austenite decomposition process for given cooling curve and finally mechanicalproperties of final product after cooling (hardness, yield stress, tensile strength are calculated. Implementationof MECHP tool into the software RollFEM3D for 3D Finite Elements Method simulation of rolling processesis presented.Findings: Comparison of MECHP calculations with measured process data (water cooling and subsequent aircooling of hot rolled narrow plate and wire shows correspondence that is satisfactory for using in control ofprocess cooling technology.Practical implications: Results of verification showed that the software tool MECHP is implementable asa postprocessor into off-line rolling process simulation software or can be used as a mechanical propertiespredictor in software for on-line control of cooling.Originality/value: Developing of technology independent Library solving the problem of final mechanicalproperties prediction for various kinds of rolling technologies.

P. Šime?ek

2007-01-01

432

Design of tooling for cold rolling of Zry tubes  

International Nuclear Information System (INIS)

Nuclear power stations use uranium dioxide as a fuel for energy production. The uranium containing fuel elements require a material, for its structural parts, capable of both withstanding the highly demanding operating conditions and showing a high transparency to neutrons. The material used in the local power stations is a zirconium based alloy with tin, iron and chromium called Zry 4. The Zry 4 fuel cladding consists of thin walled seamless tubing obtained from double vacuum arc melted ingots, by a process that includes hot forging and extrusion and a cold rolling sequence with intermediate annealing treatments. Cold rolling is performed using several variations of pilger rolling and is determinant of the geometrical and metallurgical quality of the tube. Several aspects of the process are analyzed in the present work, as well as the results of a number of trials performed at an industrial plant, with the aim of establishing the rolling conditions and the appropriate tooling required to increase productivity by changes in rolling feed, using the original design as a starting point. A sequence for the design of tooling is presented as a conclusion, including the design of rolls, mandrels and straps. Future development activities are also suggested. (author)

433

Influence of the GZ calculation method on parametric roll prediction  

DEFF Research Database (Denmark)

Parametrically excited roll response in a container ship sailing in irregular head sea has been studied. Short-term predictions for roll have been made for a ship at a constant forward speed based on different hydrodynamic roll descriptions.The first order reliability method (FORM) has been used to obtain the probability that the roll motion will exceed a given limiting angle. The results have been compared to the results by a Monte Carlo simulation. Using FORM the computational time is greatly reduced as compared to direct simulations, still retaining the probability of failure of the correct order of magnitude. Calculations have been made for different sea states and operational conditions leading to parametric roll resonance and for relevant maximum pre-defined roll angles. The outcome of this comparative study could be useful for the decisions in an early design phase or for application to on-board decision support systems, where a computationally efficient method is needed in order to have an operationally feasible time frame.

Vidic-Perunovic, Jelena

2011-01-01

434

Annealing behavior of cold-rolled reactor pressure vessel steel  

International Nuclear Information System (INIS)

An isochroanl and isothermal annealing study was performed with use of the cold rolled RPV steel(SA 508 Cl. 3 steel). Vickers microhardness and positron annihilation technique were used to understand the behavior of recovery and recrystallization. The cold-rolled specimens have represented work hardening, of which major mechanism was thought as a role of density and distribution of generated dislocations by cold rolling. Isochronal annealing experiment indicated that at least two recovery stages were observed during the annealing of the cold-rolled specimens. The first recovery process appeared, in the lower temperature, below 250 .deg. C. It is due to annealing out of vacancies, which was indicated with a drop of S parameter to the measured value of underformed specimen. The second drop in the Doppler Line-shape parameters (Stage II) occurred in the temperature range of 400 .deg. C sim 550 .deg. C. Because there was slight hardening (6.5% increase of Micro-hardness) in this temperature range, it can be thought that there were formation and sharpening of dislocation cell, and/or interaction of alloy elements with dislocations. Furthermore, only above 550 .deg. C, the cold-rolled (60%) RPV steel initiated the recrystallization. The behavior of recovery and recrystallization in the cold-rolled RPV steel, is very complex, and therefore must be systematically studied

435

New surface layers with low rolling resistance tested in Denmark  

DEFF Research Database (Denmark)

The project ‘CO2 emission reduction by exploitation of rolling resistance modeling of pavements’ (COOEE) was started in 2011 to establish a scientific background for development of novel pavement types and asset management solutions that minimize the rolling resistance for cars and trucks, the purpose being to reduce CO2 emission from the transport sector. In summer 2012, three different test sections were constructed on a highway located near Vordingborg, Denmark, in order to verify the respective Rolling Resistances; the main purpose was to develop and design new surface layers with reduced Rolling Resistance coefficient that could improve energy efficiency of the roads. In particular, two new types of Split Mastic Asphalt (SMA) were developed and compared to a reference one; both mixtures have a relatively small maximum grain-size, 6 mm and 8 mm, respectively. Surface measurements such as Skid Resistance and Mean Depth Profile were appropriately verified in order to fulfill these essential texture values. Samples were taken and studied in the laboratory to analyze the volumetric characteristics. Rolling resistance measurements have shown that both new SMAs have a reduced Rolling Resistance compared to the traditional one.

Pettinari, Matteo; Schmidt, Bjarne

2014-01-01

436

Gait deviations induced by visual stimulation in roll.  

Science.gov (United States)

Locomotion control uses proprioceptive, visual, and vestibular signals. The vestibular contribution has been analyzed previously with galvanic vestibular stimulation (GVS), which constitutes mainly a virtual head-fixed rotation in the roll plane that causes polarity-specific deviations of gait. In this study we examined whether a visual disturbance has similar effects on gait when it acts in the same direction as GVS, i.e., when roll vection is induced by head-fixed visual roll motion stimulation. Random dot patterns were constantly rotated in roll at +/-15 degrees /s on a computer-driven binocular head-mounted display that was worn by eight healthy participants. Their gait trajectories were tracked while they walked a distance of 6 m. A stimulation effect was observed only for the first three to four steps, but not for the whole walking distance. These results are similar to the results of previous GVS studies, suggesting that in terms of the direction of action visual motion stimulations in the roll plane are similar to GVS. Both kinds of stimulation cause only initial balance responses in the roll plane but do not contribute to the steering of gait in the yaw plane. PMID:17909767

Schneider, Erich; Jahn, Klaus; Dieterich, Marianne; Brandt, Thomas; Strupp, Michael

2008-02-01

437

Effects of pitching and rolling on reactor power  

International Nuclear Information System (INIS)

Present report is described about the effect of pitching and rolling on 'MUTSU' reactor power. Using the vertical gyro and the acceleration detectors, we measured pitching and rolling in addition to physical quantities from the nuclear reactor instrumentations on a voyage for N.S.'MUTSU' Power-Up Tests. This data was used to apply a multivariable autoregressive model to analyze the correlations between pitching-angle, rolling-angle, steam flow (load), neutron flux (power) and primary coolant temperature. Concerning reactor kinetics, we got a result that the pitching and rolling have no effect on primary coolant temperature and neutron flux. It is found that the frequencies at high coherence between load and power is lower and separate from the frequencies at the pitching and rolling. The pitching and rolling mainly depend on the size, weight and position of center of gravity of the ship, on the other hand the load-follow characteristics depend on the load and heat capacities of primary loop and secondary loop of the reactor. For this reason we interpret that the design of reactor and ship of N.S.'MUTSU' match well each other. (author)

438

Experimental and Theoretical Study on Minimum Achievable Foil Thickness during Asymmetric Rolling  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Parts produced by microforming are becoming ever smaller. Similarly, the foils required in micro-machines are becoming ever thinner. The asymmetric rolling technique is capable of producing foils that are thinner than those produced by the conventional rolling technique. The difference between asymmetric rolling and conventional rolling is the ‘cross-shear’ zone. However, the influence of the cross-shear zone on the minimum achievable foil thickness during asymmetric rolling is still unce...

Tang, Delin; Liu, Xianghua; Song, Meng; Yu, Hailiang

2014-01-01

439

Effect of rolling mode on the development of texture in maragining steels grade 350  

International Nuclear Information System (INIS)

Two modes of cold rolling i.e. unidirectional and reverse rolling are employed to achieve 50 and 70 % reduction. The intensity of texture components in reverse rolling was always found higher as compared to the unidirectional rolling which is attributed to the difference in the characteristic modes of deformation. Microstructural investigation reveals elongated grains, the severity of which is related with the amount of rolling reduction. TEM showed a higher density of dislocations even at 30% reduction. (author)

440

A review of contemporary solutions for cold rolling that allow quality improvement  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Purpose: of this paper is a literature review on cold rolling of products with tight dimensional tolerances.Design/methodology/approach: In this paper a review on methods of quality improvement of cold rolled products was performed. Main groups of analysed factors, influencing high quality of rolled products are: rolling equipment, rolling technology, used tools.Findings: As a result of literature review it is concluded that the most important element involved in the manufacturing process and...

Soszyn?ski, W.; Studnicka, A.

2012-01-01

 
 
 
 
441

Development of manufacturing process of wrought magnesium alloy sheets by twin roll casting  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Purpose: The purpose of the work is to development of a strip casting technology for manufacturing magnesiumalloy sheets. The aim of the work is to establish a manufacturing process and technology to facilitate theeconomical manufacture of high-strength magnesium sheet alloys.Design/methodology/approach: A horizontal type twin roll caster was used to manufacture magnesium alloysheets. Pair of copper alloy roll, pure copper roll and steel roll was used for the horizontal type twin roll caster....

Watari, H.; Paisarn, R.; Haga, T.; Noda, K.; Davey, K.; Koga, N.

2007-01-01

442

Ring rolling of AW5083 large rings for the external cylinder of CMS  

CERN Multimedia

Picture 1: The forged cylinder is engaged in the ring rolling plant. Picture 2: Vertical rolls allow for the reduction in the axial direction. Rolling is carried out at approx. 400 degrees C. Horizontal rolls (not shown) allow for the reduction in the radial direction. Picture 3: Handling of the ring, rolled at the internal diameter of approx. 7m, and transfer to the quenching both. All pictures have been taken during the visit of Mr. Sgobba at Dembiermont, Mobeuge (Bruxelles).

S. Sgobba / EST

2001-01-01

443

Study of temperature distribution over sections of blooms and slabs after rolling  

International Nuclear Information System (INIS)

The photographic method of temperature mesurement has been used to prepare the quantitative data about non-uniformity of the temperature fields over sections of blooms and slabs from the alloyed steels (12Kh18N10T, 08Kh18N10T) at the rolling. It is shown that increase of the number of rolling canting and decrease of water quantity, getting on the rolling from the cooled rolls helps in decrease of asymmetry of temperatures distribution by rolling height

444

Computation of Viscous Free-Surface Hydrodynamics for Ships during Free-Roll, Wave-Excited Roll and Prescribed Motions  

Science.gov (United States)

Prediction of ship motions in waves and the role of viscous effects remains an important problem in naval hydrodynamics. A computational fluid dynamics (CFD) solver has been developed which can simulate the unsteady turbulent boundary layer, wave field, and 6DOF dynamics of a floating body in waves. The solver is based upon the Reynolds-averaged Navier-Stokes equations, and volume-of-fluid (VOF) and dynamic-meshing algorithms. It is used to study free-roll, wave-excited roll, and forced heave and sway motions. Solution validation is achieved by comparing roll-amplitude decay, natural frequency, and response amplitude operator (RAO) for a 2D box barge in regular waves to experimental data. As a practical example, a ship hullform, with and without bilge keels, is studied when undergoing prescribed roll, sway, and heave motions. Details of the fluid dynamics and forces and moments will be correlated to motion amplitudes and frequencies.

Smith, Kevin; Paterson, Eric

2008-11-01

445

High?Volume Processed, ITO?Free Superstrates and Substrates for Roll?to?Roll Development of Organic Electronics  

DEFF Research Database (Denmark)

The fabrication of substrates and superstrates prepared by scalable roll-to-roll methods is reviewed. The substrates and superstrates that act as the flexible carrier for the processing of functional organic electronic devices are an essential component, and proposals are made about how the general availability of various forms of these materials is needed to accelerate the development of the field of organic electronics. The initial development of the replacement of indium-tin-oxide (ITO) for the flexible carrier materials is described and a description of how roll-to-roll processing development led to simplification from an initially complex make-up to higher performing materials through a more simple process is also presented. This process intensification through process simplification is viewed as a central strategy for upscaling, increasing throughput, performance, and cost reduction.

Hösel, Markus; Angmo, Dechan

2014-01-01

446

Just Roll with It? Rolling Volumes vs. Discrete Issues in Open Access Library and Information Science Journals  

Directory of Open Access Journals (Sweden)

Full Text Available INTRODUCTION Articles in open access (OA journals can be published on a rolling basis, as they become ready, or in complete, discrete issues. This study examines the prevalence of and reasons for rolling volumes vs. discrete issues among scholarly OA library and information science (LIS journals based in the United States. METHODS A survey was distributed to journal editors, asking them about their publication model and their reasons for and satisfaction with that model. RESULTS Of the 21 responding journals, 12 publish in discrete issues, eight publish in rolling volumes, and one publishes in rolling volumes with an occasional special issue. Almost all editors, regardless of model, cited ease of workflow as a justification for their chosen publication model, suggesting that there is no single best workflow for all journals. However, while all rolling-volume editors reported being satisfied with their model, satisfaction was less universal among discrete-issue editors. DISCUSSION The unexpectedly high number of