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1

Control for Cold Rolling Mills  

Digital Repository Infrastructure Vision for European Research (DRIVER)

This report contains the details in a final research thesis work done rolling mill technology. The work is carried out at Heat Transfer located at Finspång. The main objective of this work is to evaluate thickness and flatness data from the profile to give an optimal start value for the pressure and force applied on the machine and the speed as well, so that the profiles produced, have the right thickness and best possible flatness. Thickness, start value for power, the degree of bending the...

Morad, Antoni; Travancic, Faruk

2005-01-01

2

Metallurgical analysis of spalled work roll of hot strip mill  

International Nuclear Information System (INIS)

In this study failure analysis of four work roll of the Hot Strip Mill is carried out. The microstructure is correlated with the chemical composition of shell and roll-life. It was concluded that for the longer service of the roll, cementite, graphite and martensite should be balanced (as per working requirement of the mill). (author)

1993-01-01

3

Heavy metals adsorption on rolling mill scale  

International Nuclear Information System (INIS)

A great quantity of industries are responsible for contaminating the environment with the heavy metals which are containing in their wastewaters. The recovery of these metals is both from an environmental and economical points of view of the upmost interest. A study is made of the use of mill scale-originating in the hot rolling of steel-as an adsorbent for the removal of heavy metals from liquid effluents. The adsorption of Zn''2+, Cd''2+ y Pb''2+ on the rolling mill scale was investigated by determination of adsorption isotherms. The effect of time, equilibrium temperature and concentration of metal solution on mill scale adsorption efficiency was evaluated. The adsorption process was analysed using the theories of Langmuir and Freundlich. Desorption process of metals from loaded mill scales was also studied using several doser bent at different experimental conditions. It has been proved that the mill scale is an effective adsorbent for the cations studies in aqueous solutions within the range of the working concentrations. (Author) 32 refs

2003-01-01

4

Analysis of roll stack deflection in a hot strip mill  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Predictive models are required to provide the bending set point for bending for the flatness control devices at rolling stands of finishing mill of Hot Strip Mill (HSM). A simple model for roll stack deflection at the finishing mill has been illustrated where a modified Misaka’s equation has been used to obtain mean flow-stress. Investigation has been performed to understand the effect of width of roll on roll stack deflection. The bending on the deflection has been found to have a positive...

Sudipta Sikdar; Shylu John; Ashwin Pandit; Raju Dasu

2007-01-01

5

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

6

Performance characteristics of mill rolls from graphite chromium cast iron  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The main requirements for the development of a new grade for the later finishing section of the mill are : good oxidation and thermal behaviour, high wear resistance, good resistance to rolling incidents. The approach of Marichal Ketin to improve the rolling performances in the last finishing stands is presented. The Hi-Cr cast iron possesses excellent wear resistance due to the presence of hard chromium carbides, but its thermal conductivity and sticking properties are fairly low. A graphite...

Lecomte-beckers, Jacqueline; Terziev, L.; Breyer, J. P.

2000-01-01

7

PVD Coated Mill Rolls for Cold Rolling of Stainless Steel Strips: Tribological and Mechanical Laboratory Tests  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The cost of rolling is determined in particular by productivity (i.e. reduction per pass and speed) and lifetime of rolls before regrinding. Adhesive wear of the sheet gives rise to transfer on the roll surface (called "roll-coating" or "pick-up"). Its occurrence depends on rolling conditions (load, speed, temperature, lubrication) and is one of the determining factors of the maximal reduction for a given rolling speed. Abrasive wear of the roll is the second factor for roll lifetime. Both ph...

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

2012-01-01

8

Effect of hot rolling lubrication in a pilot plant mill - Second experimental report  

Energy Technology Data Exchange (ETDEWEB)

Experiments with hot rolling lubrication in a pilot plant rolling mill have been carried out at MEFOS (Foundation for metallurgical research) Metal Working Research Plant. The rolling was carried out as a controlled rolling in 930 deg C and 880 deg C and as a conventional rolling on Nb-alloyed steel billet which were flat rolled to 12 mm, 8 mm, 6 mm and 5 mm thickness. The influence of lubrication on the rolling force and torque in controlled rolling is smaller than that in conventional rolling, when the rolling product thickness is 5 mm and 6 mm. Around max. 20% rolling force decrease was achieved in conventional rolling. The effect of lubrication is related to the L/H value, but due to the scale which was formed during the holding period in controlled rolling the effect of lubrication was decreased in controlled rolling. According to the results of the test, the economic benefit is analysed when using lubricant in controlled rolling and conventional rolling. The possibility of using hot rolling lubricant in controlled rolling in a weak rolling mill is also discussed.

Jarl, M.; Li Xiaoyu

1988-09-30

9

Modelling for control of a steckel hot rolling mill  

Energy Technology Data Exchange (ETDEWEB)

In this work the derivation of a nonlinear plant simulator of a Steckel Hot Rolling Mill process is shown. The simulator reflects the thickness crown and tension behaviour of the strip, while the temperature, shape and flatness behaviour of the strip fall outside the scope of this work. Roll gap, stand, tension and hydraulic actuator models are incorporated in order to yield the simulator. The nonlinear simulator is used to identify a linear model for control system design. The linear model was identified at a certain operating point associated with a particular pass of a multiple pass rolling schedule. Step tests were applied to the manipulated variables of the simulator, and using system identification (SID) techniques a linear time invariant (LTI) multivariable input output (MIMO) transfer function model was identified. Lastly an initial control problem is formulated. (author)

Scholtz, E.

2000-10-01

10

Recycle of valuable products from oily cold rolling mill sludge  

Science.gov (United States)

Oily cold rolling mill (CRM) sludge contains lots of iron and alloying elements along with plenty of hazardous organic components, which makes it as an attractive secondary source and an environmental contaminant at the same time. The compound methods of "vacuum distillation + oxidizing roasting" and "vacuum distillation + hydrogen reduction" were employed for the recycle of oily cold rolling mill sludge. First, the sludge was dynamically vacuum distilled in a rotating furnace at 50 r/min and 600°C for 3 h, which removed almost hazardous organic components, obtaining 89.2wt% ferrous resultant. Then, high purity ferric oxide powders (99.2wt%) and reduced iron powders (98.9wt%) were obtained when the distillation residues were oxidized and reduced, respectively. The distillation oil can be used for fuel or chemical feedstock, and the distillation gases can be collected and reused as a fuel.

Liu, Bo; Zhang, Shen-gen; Tian, Jian-jun; Pan, De-an; Liu, Yang; Volinsky, Alex A.

2013-10-01

11

Optimization of a Heavy Continuous Rolling Mill System Via Simulation  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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...

Ali Azadeh; Farid Ghaderi

2006-01-01

12

Variable-speed drive and control systems for rolling mills; Atsuenkiyo drive seigyo system  

Energy Technology Data Exchange (ETDEWEB)

The drive systems of large rolling mills is of a cycloconverter type, a GTO (gate turn-off thyristor) type or high-voltage IGBT (insulated gate bipolar transistor) type. Drive systems for bar, rod and pipe mills use three and/or two level IGBT inverters. This paper describes recent technical trends of drives and control systems in rolling mills, including each drive application and the PLC (programmable controller) and HCI (human communication interface) controlling the total rolling mill line. (author)

Kasai, T.; Tochigi, T. [Fuji Electric Co. Ltd., Tokyo (Japan)

2000-11-10

13

Differential speed two roll mill pretreatment of cellulosic materials for enzymatic hydrolysis.  

Science.gov (United States)

Differential speed two roll milling is an effective pretreatment for increasing the susceptibility of cellulose to enzymatic hydrolysis. Using mills with three, six, and ten in. diam rolls and processing times of 10 min or less results in the following percent increases in susceptibility over untreated controls: cotton, 1100; maple chips, 1600; white pine chips, 600; newspaper, 125. In comparison, ball milling of newspaper for 24 hr gives only a 62% increase. A further advantage of the roll mill is the increased wet density of the product permitting higher slurry concentrations during hydrolysis. Important parameters of mill effectiveness are roll clearance and processing time PMID:890083

Tassinari, T; Macy, C

1977-09-01

14

Use of a finite element method to calculate roll profiles for broad-strip mills  

Science.gov (United States)

A model is proposed to calculate the polishing profiling of rolls in broad-strip mills using a finite element method, and it is applied to develop new roll profiles. The finite element method is used to determine the polishing profiling of a roll with a complex shape, which substantially decreases the nonuniformity of reduction and drawing over the strip width. This profiling can be executed on numerical control roll grinders.

Garber, E. A.; Bolobanova, N. L.; Traino, A. I.

2012-05-01

15

Study on the improved accuracy of strip profile using numerical formula model in continuous cold rolling with 6-high mill  

International Nuclear Information System (INIS)

The quality requirements for thickness accuracy in cold rolling continue to become more stringent. In cold rolling mill, it is very important that the rolling force calculation considers rolling conditions. The rolled strip thickness was predicted using calculated rolling force. However, the prediction of strip thickness in cold rolling is very difficult; in particular, for 6-high mill with shifted intermediate roll (IMR), the accuracy of thickness is not good. In this study, to improve the accuracy of rolled strip thickness, the roll gap flattening can be given based on Hertz contact theory, with contact between rolls and the smooth cylindrical rolls for the rolling elastic deformation. Also, the distribution of the roll gap flattening may be calculated using the contact force of unit transverse length. The strip profile at the continuous cold rolling is calculated by using the numerical analysis model considering the initial strip profile before cold rolling. Hence, we propose that the numerical model can predict the rolled strip profile more quickly and accurately and be applicable to the field. The results of the proposed numerical model were verified by FE-simulation and cold rolling experiments of 6-high mill with five stands

2011-08-01

16

Study on the improved accuracy of strip profile using numerical formula model in continuous cold rolling with 6-high mill  

Energy Technology Data Exchange (ETDEWEB)

The quality requirements for thickness accuracy in cold rolling continue to become more stringent. In cold rolling mill, it is very important that the rolling force calculation considers rolling conditions. The rolled strip thickness was predicted using calculated rolling force. However, the prediction of strip thickness in cold rolling is very difficult; in particular, for 6-high mill with shifted intermediate roll (IMR), the accuracy of thickness is not good. In this study, to improve the accuracy of rolled strip thickness, the roll gap flattening can be given based on Hertz contact theory, with contact between rolls and the smooth cylindrical rolls for the rolling elastic deformation. Also, the distribution of the roll gap flattening may be calculated using the contact force of unit transverse length. The strip profile at the continuous cold rolling is calculated by using the numerical analysis model considering the initial strip profile before cold rolling. Hence, we propose that the numerical model can predict the rolled strip profile more quickly and accurately and be applicable to the field. The results of the proposed numerical model were verified by FE-simulation and cold rolling experiments of 6-high mill with five stands.

Lee, Sang Ho; Kim, Byung Min [Pusan National University, Busan (Korea, Republic of); Song, Gil Ho; Lee, Sung Jin [POSCO, Pohang (Korea, Republic of)

2011-08-15

17

Premature failure analysis of forged cold back-up roll in a continuous tandem mill  

International Nuclear Information System (INIS)

Highlights: ? Metal wrapping and strip welding in work/back-up rolls contact zone caused spalling. ? MnS inclusion and pore initiated crack which propagated in milling led to spalling. ? Retained austenite conversion to ?'-martensite accelerated spalling failure. ? Needle shaped carbide (Fe,Mo,Cr)7C3, may cause poor service life of back-up roll. -- Abstract: In this paper, premature failure of a forged back-up roll from a continuous tandem mill was investigated. Microstructural evolutions of the spalled specimen and surface of the roll were characterized by optical microscopy, X-ray diffraction, scanning electron microscopy and ferritscopy, while hardness value of the specimen was measured by Vickers hardness testing. The results revealed that the presence of pore and MnS inclusion with spherical and oval morphologies were the main contributing factors responsible for the poor life of the back-up roll. In addition, metal pick up and subsequently strip welding on the surface of the work roll were found as the major causes of failure in work roll which led to spalling occurrence in the back-up roll. Furthermore, relatively high percentage of retained austenite, say 9%, in outer surface of the back-up roll contributed spalling due to conversion of this meta-stable phase to martensite and creation of volume expansion on the outer surface through work hardening during mill campaign.

2011-09-01

18

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

19

Research upon the quality assurance of the rolling-mill rolls and the variation boundaries of the chemical composition  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The cast-iron rolls must present higher hardness at the rolling surface and lower in the core and the necks, adequate with mechanical resistance and in the high work temperature. If in the zone of the rolling surface, the hardness is guarantied by the irons structure, through the cementite quantities, the core of rolls must contain graphite, to assure this property. Starting from the lamination equipments aspects, from the form of rolls, of the technological interest zones and the structure, ...

Kiss, I.

2008-01-01

20

Preparation and properties of barium ferrite using hot-rolled mill scale  

Energy Technology Data Exchange (ETDEWEB)

Commercial-quality barium ferrite was made on a laboratory scale by the solid-state reaction of raw hot-rolled mill scale and barium carbonate. The processing parameters are reported. The mechanism of ferrite formation is proposed.

Chien, Y.T.; Pan, H.C.; Ko, Y.C. (China Steel Corp., Kaohsiung, Taiwan (TW))

1989-08-01

 
 
 
 
21

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.

Gálvez J. M.

2003-01-01

22

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)

2000-08-20

23

Actuator fault detection, isolation method and state estimator design for hot rolling mill monitoring  

Digital Repository Infrastructure Vision for European Research (DRIVER)

This paper proposes a method for actuator fault diagnosis in a speed control loop of a hot roughing rolling mill used to carry out multi-pass forward-forward or forward-reverse rolling. The main objectives of the work is to first improve an actuator fault detection and fault magnitude estimation problem for a particular system and second to estimate non measurable variables in order to provide suitable information to the monitoring system. According to fault diagnosis theory and the specific ...

Theilliol, Didier; Mahfouf, Mahdi; Sauter, Dominique; Gama, Miguel Angel

2006-01-01

24

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

25

Influence of a matrix on properties of mottled cast iron applied for mill rolls  

Directory of Open Access Journals (Sweden)

Full Text Available Mill rolls are ones of the most expensive tools applied in plastic working processes and have to satisfy several criteria, which allow them to be used. Cast iron mill rolls, due to their fracture toughness and tribological properties, are the most often applied at hot-rolling in the last rolling stands. This results from the smallest dynamic loads of such rolling stands and the decisive influence of the surface quality of these tools on the surface quality of the rolled product. An improper microstructure of rolls can lead to their premature wearing, e.g. broken flanges, pivots twisting off etc. By means of the heat treatment the matrix microstructure and morphology of carbide precipitationscan be modified and this in-turn can influence cast iron properties.Determination of the influence of microstructure changes, caused by the heat treatment, on the properties of EN-GJN-HV300 low-alloycast iron, after its modification and spheroidization – is the aim of the present paper. Those changes are based on the formation pearlitic or bainitic matrices at the similar morphology of graphite and ledeburitic cementite precipitations. The performed investigations should enable designing the heat treatment of cast iron metallurgical rolls in such a way as to obtain the optimal microstructures for functional parameters of these type of tools. The influence of changing the pearlitic matrix into the bainitic one on such properties as: hardness, impact strength, tensile strength, creep limit, bending strength and a stress intensity factor KIc was investigated in this study. Samples for testing, the listed above mechanical properties, were taken from an industrial casting with care to have pieces of very similar crystallization conditions.

J. Krawczyk

2010-07-01

26

Rolling reloaded  

International Nuclear Information System (INIS)

Not so long ago a new observation about rolling motion was described: for a rolling wheel, there is a set of points with instantaneous velocities directed at or away from the centre of the wheel; these points form a circle whose diameter connects the centre of the wheel to the wheel's point of contact with the ground (Sharma 1996 Eur. J. Phys. 17 353-6). We provide a detailed experimental verification of this observation, collecting 3D data from a rolling wheel with a commercially available optical tracking system. We also extend the observation to a generalized form: for a rolling wheel, there is a set of points with instantaneous velocities directed at or away from any point P; these points form a circle whose diameter connects the point P to the wheel's point of contact with the ground. This generalization is also verified experimentally

2008-03-01

27

Merging of advices from multiple advisory systems - with evaluation on rolling mill data.  

Czech Academy of Sciences Publication Activity Database

multiple-participant decision-makingKód oboru RIV: BC - Teorie a systémy ?ízení http://library.utia.cas.cz/separaty/2009/AS/andrysek-merging of advices from multiple advisory systems-with evaluation on rolling mill data.pdf

Ettler, P.; Andrýsek, Josef; Šmídl, Václav; Kárný, Miroslav

28

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.

29

Roll Call  

Science.gov (United States)

Roll Call is "The Newspaper of Capitol Hill since 1955", that covers the people, process and politics of Capitol Hill. The website has many multimedia features, including videos, an interactive timeline, podcasts, photo galleries, and political cartoons. Some of the sections of the online version of the paper include "News", "Opinion", "Politics", "Vested Interests", "Around the Hill", and "Investigations". To watch videos on various topics, or listen to Roll Call podcasts, visitors should click on "More Video", in the box entitled Roll Call Video, which resides in the middle of the page. The link provides recent videos, Roll Call on C-SPAN, Roll Call TV (CN8), podcasts, and a photo gallery of photos of the day. At the top of the homepage, visitors can find the latest news from Congress and the judiciary under the "Congress Now" tab. For policy intelligence on many issues, the "Briefing Room" tab allows visitors to explore the latest issues, divided into the topics of "Budget and Appropriations", "Defense", "Energy and Environment", "Foreign Policy and Trade", "Health", and "Homeland Security".

30

Actuator/sensor fault diagnosis for an experimental hot rolling mill - A case study  

Digital Repository Infrastructure Vision for European Research (DRIVER)

This paper proposes a method for actuator/sensors fault diagnosis in a speed control loop of a hot roughing rolling mill used to carry out multi-pass forward-forward or forward-reverse rolling. According to fault diagnosis theory and the specific application domain, the main objective of the work is to develop a model-based fault detection filter combined with a conventional Luenberger observer. Based on an appropriate gain, the developed technique enables to supervise the hot roughing rollin...

Theilliol, Didier; Mahfouf, Mahdi; Sauter, Dominique; Ponsart, Jean-christophe

2006-01-01

31

Hot sheet rolling on continuous mill under plastic fluid friction conditions. [12Kh18N10T  

Energy Technology Data Exchange (ETDEWEB)

A technique for hot sheet rolling in plastic fluid friction conditions of sheets of the 12Kh18N10T and carbon 10 sp steels is developed and tested. A new lubricant ''Silicatherm'' constitutes the basis of the technique. The advantages of the given technique as compared to the rolling with liquid lubricants of mineral and vegetative origin as well as the prospects of its introduction during hot rolling on continuous mills are shown.

Kolmogorov, V.L.; Spasskii, Yu.I.; Serebryakov, A.V.; Gindin, A.Sh.; Shavkun, V.V. (Ural' skii Politekhnicheskij Inst., Sverdlovsk (USSR))

1981-01-01

32

Wireless Remote Monitoring System for the Agc Svibration Fault of Rolling Mill  

Directory of Open Access Journals (Sweden)

Full Text Available The rolling mill screw down AGC system sets several subsystems of machinery, electronics, hydraulics, controls in one. Under the action of responding extreme frequency or external disturbances, the non design objective coupling between the subsystems may be excited, and causing the most serious vibration, seriously impact product quality or even cause great destruction. Aiming at the defects in fault diagnosis and control system of the traditional rolling mill, the wireless remote monitoring system for the rolling mill AGC system vibration fault is designed in this paper. Using the advanced sensor technology, PLC and configuration software, GPRS network technology, the parallel distributed data acquisition and data processing for the key servo element and the hydraulic parameters which can characterize the fault characteristics of the system can be done. The monitoring software system platform on line of the hydraulic AGC system based on Kingview is set up for centralized real-time monitoring. According to the collected multidisciplinary parameter the fault identification and location is done by using the fault diagnosis expert system based on Web, thus to make the preliminary evaluation for the operation and fault of hydraulic AGC system and provide advanced prediction and exclude strategy.

Yan Gao

2013-01-01

33

Heavy metals adsorption on rolling mill scale; Adsorcion de metales pesados sobre cascarill de laminacion  

Energy Technology Data Exchange (ETDEWEB)

A great quantity of industries are responsible for contaminating the environment with the heavy metals which are containing in their wastewaters. The recovery of these metals is both from an environmental and economical points of view of the upmost interest. A study is made of the use of mill scale-originating in the hot rolling of steel-as an adsorbent for the removal of heavy metals from liquid effluents. The adsorption of Zn''2+, Cd''2+ y Pb''2+ on the rolling mill scale was investigated by determination of adsorption isotherms. The effect of time, equilibrium temperature and concentration of metal solution on mill scale adsorption efficiency was evaluated. The adsorption process was analysed using the theories of Langmuir and Freundlich. Desorption process of metals from loaded mill scales was also studied using several doser bent at different experimental conditions. It has been proved that the mill scale is an effective adsorbent for the cations studies in aqueous solutions within the range of the working concentrations. (Author) 32 refs.

Lopez, F. A.; Martin, M. I.; Perez, C.; Lopez-Delgado, A.; Alguacil, E. J.

2003-07-01

34

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

35

An investigation of rolling pressure on metallic uranium rod  

Energy Technology Data Exchange (ETDEWEB)

An investigation of rolling pressure on metallic uranium rod was made. The behavior of uranium metal in rolling mills was considered as a viscous flow. Then the differential equation for rolling pressure was established. The calculation formula for rolling pressure was derived from the equation and theoretical calculation method for rolling pressure was given. Values of rolling pressure were calculated according to the calculation formula. Values of rolling pressure, coefficient of contact friction and lateral expansion of uranium rod were measured in rolling mills. The calculated rolling pressure was compared with that measured in rolling mills.

Meng, Z.

1984-01-01

36

Investigation of rolling pressure on metallic uranium rod  

Energy Technology Data Exchange (ETDEWEB)

The rolling pressure on metallic uranium rod was investigated. By considering the behavior of the uranium metal in a rolling mill as a viscous flow, the differential equation for the rolling pressure was established. A formula for calculating the rolling pressure was derived and the theoretical calculation method was given. The rolling pressure, the coefficient of contact friction, and the lateral expansion of uranium rod were measured. The measured rolling pressure was compared to the calculated value. Rolling is an important forming technique for uranium. A study of the rolling parameters of uranium serves as a basis for rolling mill design, engineering calculation, and rolling mill strength calibration.

Zhang, M.

1984-06-01

37

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

38

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

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

Rolling and annealing texture in twin roll cast commercial purity aluminium  

Energy Technology Data Exchange (ETDEWEB)

The development of cold rolling and annealing texture in twin roll cast commercial aluminium has been studied, varying rolling conditions such as lubricant and rolling speed in laboratory rolling and by comparing laboratory rolled sheets to that from a commercial mill. The tendency to formation of shear texture in the surface of laboratory rolled sheets was promoted by high surface friction and low rolling speeds, while well lubricated rolls and high speeds resulted in a plane strain type texture also in the sheet surface. The latter was also typical of industrial rolling. The effect of the surface deformation mode and texture on the grain structure resulting from the subsequent annealing has also been studied. The shear texture in laboratory rolled sheets were associated with a smaller grain size than industrially rolled sheets. (orig.)

Benum, S. (SINTEF, Div. of Metallurgy, Trondheim (Norway)); Engler, O. (Inst. fuer Metallkunde und Metallphysik, RWTH Aachen (Germany)); Nes, E. (Norwegian Inst. of Tech., Dept. of Metallurgy, Trondheim (Norway))

1994-01-01

 
 
 
 
41

Rolling of bars and sections of fire-resisting metals on mills with noulti-shaft calibers  

International Nuclear Information System (INIS)

Summarized in this paper are the results of experimental studies and rolling of rods and sections from metal-ceramic and cest molybdenum and tungsten. The technical characteristics of the new MK-200 laboratory mill are given together with the calibaration scheme of tungsten and molybdenum rods

1976-01-01

42

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

Energy Technology Data Exchange (ETDEWEB)

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.

Kaper, T.J.; Wiggins, S. (California Inst. of Tech., Pasadena, CA (USA))

1989-01-01

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.

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

44

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

45

Evaluation of residual uranium contamination in the dirt floor of an abandoned metal rolling mill.  

Science.gov (United States)

A single, large, bulk sample of uranium-contaminated material from the dirt floor of an abandoned metal rolling mill was separated into different types and sizes of aliquots to simulate samples that would be collected during site remediation. The facility rolled approximately 11,000 tons of hot-forged ingots of uranium metal approximately 60 y ago, and it has not been used since that time. Thirty small mass (? 0.7 g) and 15 large mass (? 70 g) samples were prepared from the heterogeneously contaminated bulk material to determine how measurements of the uranium contamination vary with sample size. Aliquots of bulk material were also resuspended in an exposure chamber to produce six samples of respirable particles that were obtained using a cascade impactor. Samples of removable surface contamination were collected by wiping 100 cm of the interior surfaces of the exposure chamber with 47-mm-diameter fiber filters. Uranium contamination in each of the samples was measured directly using high-resolution gamma ray spectrometry. As expected, results for isotopic uranium (i.e., U and U) measured with the large-mass and small-mass samples are significantly different (p 0.05) from results for the large- or small-mass samples. Large-mass samples are more reliable for characterizing heterogeneously distributed radiological contamination than small-mass samples since they exhibit the least variation compared to the mean. Thus, samples should be sufficiently large in mass to insure that the results are truly representative of the heterogeneously distributed uranium contamination present at the facility. Monitoring exposure of workers and the public as a result of uranium contamination resuspended during site remediation should be evaluated using samples of sufficient size and type to accommodate the heterogeneous distribution of uranium in the bulk material. PMID:23274821

Glassford, Eric; Spitz, Henry; Lobaugh, Megan; Spitler, Grant; Succop, Paul; Rice, Carol

2013-02-01

46

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

47

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

Directory of Open Access Journals (Sweden)

Full Text Available 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 programação 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.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 Linear 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

2013-03-01

48

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

Directory of Open Access Journals (Sweden)

Full Text Available 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 programação 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.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 Linear 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

2012-01-01

49

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

50

Birefringent Strands in Polymer Flows in a Co-rotating Two-Roll Mill  

Science.gov (United States)

We study flow of polymer solutions in a co-rotating two-roll mill. Polymer molecules are significantly extended downstream of an isolated stagnation point in the nip, creating a "birefringent strand" visible through optical experiments. The elastic stress created by the strand is approximated by a line of discontinuity in shear stress. Since the height of the nip is small in comparison to the radius of the rollers, the lubrication approximation is used for the flow and pressure fields. The tangential stress condition and conservation of flux across the nip are used to obtain ordinary differential equations for U(x), the velocity on the strand, p_x, the pressure gradient, and l(x), the position of the strand. Integration of the equations subject to boundary and integral conditions yields solutions for the strand position and velocity as functions of s, the ratio of roller speeds, and ?, a non-Newtonian parameter dependent on the the polymer concentration, maximum length, and the Deborah number. The numerical results compare well with experimental observations of l(x).

Lee, Isaac; Homsy, George

1999-11-01

51

Expert system for flatness control in aluminum foil rolling. Alumi haku mill keijo seigyo expert system  

Energy Technology Data Exchange (ETDEWEB)

This paper reports the application of an expert system for Automatic Flatness Control (AFC) in aluminum foil rolling. The expert system is connected with AFC, and adjusts the target shape pattern according to the material characteristics and the operating conditions. This system is developed on the UNIX work station, and consists of six units, three knowledge bases, and a working memory. It has shown the ability to improve all kinds of aluminum foil throughout an one year adaptation in the operational rolling process. By using this system, the speed of rolling was improved above 10 percent. The algorithm which maintains consistency among multiple control purposes and the adaptive inference method realized in this system proved to be useful as a paradigm of the knowledge base system for the control process. 1 ref., 6 figs.

Konishi, M.; Nose, K.; Narazaki, H.; Iwatani, T.; Oshima, H.; Kitagawa, S. (Kobe Steel, Ltd., Kobe (Japan))

1990-07-01

52

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...

2008-01-01

53

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

54

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

1998-04-01

55

Strip thickness estimation in rolling mills from electrical variables in AC drives  

Scientific Electronic Library Online (English)

Full Text Available SciELO Argentina | Language: English Abstract in english The large-scale utilization of steel in the modern society highlights the importance of the lamination process, and poses new demands for advanced technologies in the electromechanical equipments as well as for the control systems. Several process parameters, such as strip thickness, friction, tensi [...] on, temperature, and rolling speed have a strong influence in the quality of the final product, and strategic importance in the control system. This paper introduces a method to obtain the torque and rolling mechanical power estimates in real time, without utilization of lamination process models. In contrast to existing techniques, in this work these estimates are derived from stator electrical variables, readily available in AC drives. This work also discusses the utilization of the torque and rolling mechanical power estimates to determine input and output strip thickness, by means of a neural network. Simulation results are presented and compared to real industrial data to demonstrate the validity of the proposed technique.

Marcellos, N.S.; Denti, J.F.; Sousa, G.C.D..

56

Roll force prediction of high strength steel using foil rolling theory in cold skin pass rolling  

International Nuclear Information System (INIS)

Skin pass rolling is a very important process for applying a certain elongation to a strip in the cold rolling and annealing processes, which play an important role in preventing the stretching of the yield point when the material is processed. The exact prediction of the rolling force is essential for obtaining a given elongation with the steel grade and strip size. Unlike hot rolling and cold rolling, skin pass rolling is used to apply an elongation of within 2% to the strip. Under a small reduction, it is difficult to predict the rolling force because the elastic deformation behavior of the rolls is complicated and a model for predicting the rolling force has not yet been established. Nevertheless, the exact prediction of the rolling force in skin pass rolling has gained increasing importance in recent times with the rapid development of high strength steels for use in automobiles. In this study, the possibility of predicting the rolling force in skin pass rolling for producing various steel grades was examined using foil rolling theory, which is known to have similar elastic deformation behavior of rolls in the roll bite. It was found that a noncircular arc model is more accurate than a circular model in predicting the roll force of high strength steel below TS 980 MPa in skin pass rolling

2013-02-01

57

Roll force prediction of high strength steel using foil rolling theory in cold skin pass rolling  

Energy Technology Data Exchange (ETDEWEB)

Skin pass rolling is a very important process for applying a certain elongation to a strip in the cold rolling and annealing processes, which play an important role in preventing the stretching of the yield point when the material is processed. The exact prediction of the rolling force is essential for obtaining a given elongation with the steel grade and strip size. Unlike hot rolling and cold rolling, skin pass rolling is used to apply an elongation of within 2% to the strip. Under a small reduction, it is difficult to predict the rolling force because the elastic deformation behavior of the rolls is complicated and a model for predicting the rolling force has not yet been established. Nevertheless, the exact prediction of the rolling force in skin pass rolling has gained increasing importance in recent times with the rapid development of high strength steels for use in automobiles. In this study, the possibility of predicting the rolling force in skin pass rolling for producing various steel grades was examined using foil rolling theory, which is known to have similar elastic deformation behavior of rolls in the roll bite. It was found that a noncircular arc model is more accurate than a circular model in predicting the roll force of high strength steel below TS 980 MPa in skin pass rolling.

Song, Gil Ho; Jung, Jae Chook [Rolling and Measurement Research Group of Posco Technical Research Laboratory, Pohang (Korea, Republic of)

2013-02-15

58

VOLATILIZED LUBRICANT EMISSIONS FROM STEEL ROLLING OPERATIONS  

Science.gov (United States)

The report gives results of a study of the volatilization of lubricants used in steel rolling. Data from nine steel mills were used to: define the volatilized portion of lubricants used in rolling; and prepare total oil, grease, and hydraulic material balances for actual and typi...

59

CISM Course on Rolling Contact Phenomena  

CERN Document Server

Preface.- Rolling Contact Phenomena - Linear Elasticity.- Finite Element Methods for Rolling Contact.- Plastic Deformation in Rolling Contact.- Non-Steady State Rolling Contact and Corrugations.- Modelling of Tyre Force and Moment Generation.- Rolling Noise.- Lubrication

Kalker, Joost

2000-01-01

60

Catalytic surface modification of roll-milled poly({epsilon}-caprolactone) biaxially stretched to ultra-thin dimension  

Energy Technology Data Exchange (ETDEWEB)

A novel roll-milling polymer processing technique along with biaxial stretching was used to fabricate 10 {mu}m thick poly({epsilon}-caprolactone) films. A less invasive collagen surface modification was used, involving a reaction between corona-preactivated membranes and ferrous-containing acrylic acid solution at the low temperature of 42 {sup o}C. Successful modified films were characterized by Toluidine Blue O assay and X-ray photoelectron spectroscopy. Human umbilical vein endothelial cells also showed both higher proliferation rate and differentiated cobblestone morphology on these collagen-immobilized substrates.

Foo, H.L. [Graduate Programme in Bioengineering, National University of Singapore (Singapore); Bionic Materials Technology Group, Biomaterials Center, National Institute for Materials Science (Japan); Taniguchi, A. [Bionic Materials Technology Group, Biomaterials Center, National Institute for Materials Science (Japan); Yu, H. [Graduate Programme in Bioengineering, National University of Singapore (Singapore); Department of Physiology, National University of Singapore (Singapore); Okano, T. [Bionic Materials Technology Group, Biomaterials Center, National Institute for Materials Science (Japan); Institute of Biomedical Engineering, Tokyo Women' s Medical University (Japan); Teoh, S.H. [Graduate Programme in Bioengineering, National University of Singapore (Singapore) and Department of Mechanical Engineering, National University of Singapore (Singapore)]. E-mail: mpetsh@nus.edu.sg

2007-03-15

 
 
 
 
61

New rolling strategy for heavy plate mills. Development and installation; Nouvelle strategie de laminage pour toleries fortes. Developpement et implantation  

Energy Technology Data Exchange (ETDEWEB)

For the last few years, an evolution has been noted in the Usinor Sacilor plate mill order book going towards thinner, harder and wider products, causing a malfunction of the control system (PLATE). This problem could be solved by the development of a new strategy making it possible to exceed the flatness tolerances during the main thickness reduction phase. Installation of this new strategy in the CLI PLATE control system made it possible to increase the final temperature of the product (- 100 deg. C), to decrease the number of schema passes (up to 50 %) and thus to extend automatic rolling to finer products while guaranteeing a good final flatness. (authors)

Irastorza, L.; Dreistadt, D. [Institut de Recherches de la Siderurgie Francaise (IRSID), 78 - Saint-Germain-en-Laye (France); Lavolaine, P.; Dumoulin, P.; Martin, D.; Medalle, G. [Societe Creusot-Loire, 75 - Paris (France)

1996-07-01

62

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

63

Cost efficiency of a rolling mill furnace as a function of soaking action  

Energy Technology Data Exchange (ETDEWEB)

The maximum temperature difference shortly prior to discharge from the furnace is one of the main criteria in the reheating of slabs to be rolled into sheet. Experience has shown that in contrast to slow heating and short soaking it is preferable to heat the stock rapidly to the desired surface temperature and to keep it at this value for a prolonged period if satisfactory soaking action is to be achieved. However, conditions are reversed when it comes to the cost efficiency of the furnace. The correlations between soaking action and cost efficiency are analysed.

Behrens, H.A.

1984-04-01

64

A Robust Roll Damping Controller  

DEFF Research Database (Denmark)

The effectiveness of rudder roll damping is sensitive to ship dynamic parameters. A recent model of a containership in waves include a nonlinear model and wave response operators. The vessel is sensitive in roll and has a low metacentric height, with a long natural roll period of 25 s. It was therefore interesting to investigate whether rudder roll damping was feasible. In this paper an Hâ?? controller is designed to optimise rudder roll damping. Steering and roll damping are hierarchical loops. Sea-way simulation results show that a successful controller design can be made

Yang, Chengen; Blanke, Mogens

1999-01-01

65

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 diculties 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 dierent 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

66

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 School of Engineering,, The University of Newcastle

2010-01-01

67

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

68

Width variation defects reducing measurements at the hot rolling mill II; Medidas tomadas para reducao do defeito variacao de largura no LTQ-II  

Energy Technology Data Exchange (ETDEWEB)

This paper shows the results of the productivity gains on the rolling mill, caused by the increase of the fine adjusting on the chair activity, as well the standardization of the lopper`s working angle. 1 ref., 12 figs., 1 tab.

Tirello, Jonas; Dornelas, Francisco C.; Brandao, Jose M.M.; Vilella, Marcelo; P. Neto, Arlindo F.; Nardeli Sobrinho, Antonio [Companhia Siderurgica Nacional, Volta Redonda, RJ (Brazil)

1991-12-31

69

Rolling Stonesi kinokontsert kannab toorest rokiväge / Maris Meiessaar  

Index Scriptorium Estoniae

Martin Scorsese muusikalisest dokumentaalfilmist "Shine a Light - Valgus peale" (USA-Suurbritannia, 2008), mille keskmes on 2006. a. New Yorgi Beaconi teatris toimunud briti ansambli Rolling Stones kontsert

Meiessaar, Maris

2009-01-01

70

Ultra-thin hot rolled strip; Gokuhaku atsukan atsuen kohan  

Energy Technology Data Exchange (ETDEWEB)

Kawasaki Steel has been making efforts to develop new hot-rolled steel products by using fully continuous rolling technology, so-called 'endless rolling', at No.3 hot strip mill of Chiba Works. Stable rolling technology of ultra-thin hot rolled strips such as 1.0 mm and 0.9 mm in thickness has been established, and the conventional minimum gauge of hot rolled strips (1.2 nn) has been lowered. The ultra-thin hot rolled strips have been provided to the market with a bland name 'RTHC' (river thin hot coil commercial grade) since 1997. The ultra-thin hot rolled strips have excellent quality in dimensional accuracy and mechanical properties. In addition, the ultra-thin hot rolled strips meet current needs of energy saving and reducing CO{sub 2}. New market and more demands for the newly developed product strips are expected. (author)

Yamada, N.; Kitahama, M.; Nikaido, H. [Kawasaki Steel Corp., Tokyo (Japan)

1999-09-01

71

Inflation Without Slow Roll.  

Science.gov (United States)

We draw attention to the possibility that inflation (i.e. accelerated expansion) might continue after the end of slow roll, during a period of fast oscillations of the inflation field Mu. This phenomenon takes place when a mild non-convexity inequality is...

T. Damour V. F. Mukhanov

1997-01-01

72

Mathematical modeling of deformation during hot rolling  

Energy Technology Data Exchange (ETDEWEB)

The deformation that occurs in the roll bite during the hot rolling of steel, particularly the strain-rate and strain distribution, has been mathematically modeled using finite-element analysis. In this paper three different finite-element models are compared with one another and with industrial measurements. The first model is an Eulerian analysis based on the flow formulation method, while the second utilizes an Updated Lagrangian approach. The third model is based on a commercially available program DEFORM which also utilizes a Lagrangian reference frame. Model predictions of strain and strain-rate distribution, particularly near the surface of the slab, are strongly influenced by the treatment of friction at the boundary and the magnitude of the friction coefficient or shear factor. Roll forces predicted by the model have been compared with industrial rolling loads from a seven-stand hot-strip mill.

Jin, D.; Stachowiak, R.G.; Samarasekera, I.V.; Brimacombe, J.K. [Univ. of British Columbia, Vancouver, British Columbia (Canada). Centre for Metallurgical Processing Engineering

1994-12-31

73

Mechanical properties of chromium steels for back up rolling rolls  

International Nuclear Information System (INIS)

Back up rolling rolls are very large mechanical components which have to be designed to withstand very high contact stresses produced, under the rolling load, in the region between the working and the back up rolls, along with severe wear actions. In this investigation, the thermal treatment (bainitic isotermic quenching followed by several temper treatments) of these components is described and their most characteristic properties related to the in-service behaviour of these products are determined, using hardness, compression, fracture toughness and sliding wear tests. (Author) 7 refs

2003-01-01

74

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  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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 retrospe...

Rafiei Masoud; Gadgil Alaka; Ghole Vikram; Gore Sharad; Jaafarzadeh Neemat; Mirkazemi Roksana

2009-01-01

75

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

76

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...

77

Rolling G_2 Moduli  

CERN Document Server

We study the time evolution of freely rolling moduli in the context of M-theory on a G_2 manifold. This free evolution approximates the correct dynamics of the system at sufficiently large values of the moduli when effects from non-perturbative potentials and flux are negligible. Moduli fall into two classes, namely bulk moduli and blow-up moduli. We obtain a number of non-trivial solutions for the time-evolution of these moduli. As a generic feature, we find the blow-up moduli always expand asymptotically at early and late time.

Lukas, A; Lukas, Andre; Morris, Stephen

2004-01-01

78

Practice of Improving Roll Deformation Theory in Strip Rolling Process Based on Boundary Integral Equation Method  

Science.gov (United States)

Precise strip-shape control theory is significant to improve rolled strip quality, and roll flattening theory is a primary part of the strip-shape theory. To improve the accuracy of roll flattening calculation based on semi-infinite body model, a new and more accurate roll flattening model is proposed in this paper, which is derived based on boundary integral equation method. The displacement fields of the finite length semi-infinite body on left and right sides are simulated by using finite element method (FEM) and displacement decay functions on left and right sides are established. Based on the new roll flattening model, a new 4Hi mill deformation model is established and verified by FEM. The new model is compared with Foppl formula and semi-infinite body model in different strip width, roll shifting value and bending force. The results show that the pressure and flattening between rolls calculated by the new model are more precise than other two models, especially near the two roll barrel edges.

Yuan, Zhengwen; Xiao, Hong; Xie, Hongbiao

2014-02-01

79

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

80

Lipoid pneumonia caused by oil mist exposure from a steel rolling tandem mill  

Energy Technology Data Exchange (ETDEWEB)

Five of nine active tandem mill operators exposed at work to aerosolized hydrocarbon mist were referred for evaluation of respiratory complaints. The worker with the longest exposure had reduced lung volumes; he was admitted to the hospital for detailed study. Exercise studies revealed work load limited by ventilation and arterial oxygen desaturation. Flexible fiberoptic bronchoscopy with bronchoalveolar lavage and transbronchial biopsy revealed evidence of lipoid pneumonia. Assessment of the mill revealed levels of respirable oil mist by personal samplers throughout the area far below the currently accepted standard of 5 mg/M3. These findings confirm a 20-year-old hypothesis of J.G. Jones regarding the hazard of oil mist in this industrial setting.

Cullen, M.R.; Balmes, J.R.; Robins, J.M.; Smith, G.J.

1981-01-01

 
 
 
 
81

Numerical simulation of a hot rolling process  

Energy Technology Data Exchange (ETDEWEB)

This paper presents the findings of the effects of rolling parameters on the work roll undergoing thermal cycles through numerical simulation using the finite element method. The rolling parameters investigated are the location of the spray nozzle, the coolant spray flux, and the initial work roll temperature. The findings show that the spray nozzle is best placed near the exit of the roll bite for minimum fatigue stress. Firecracking can be eliminated by providing a large cooling flux through spraying. The initial temperature of the work roll have little effect on the roll life, but does have some influence on the quality of the rolled product.

Tso, C.P.; Tan, F.L.

1999-07-01

82

Design of two bearings with sealing system for the top roll shaft of sugar cane mill  

Scientific Electronic Library Online (English)

Full Text Available SciELO Venezuela | Language: Spanish Abstract in spanish Las chumaceras de bronce utilizadas actualmente en los molinos de caña de azúcar presentan elevado desgaste debido, entre otros factores, a la materia extraña que ingresa en ella cuando el eje superior se eleva (flota) por efecto del colchón de caña que pasa entre las mazas y al sobrecalentamiento c [...] ausado por fallas en los sistemas de lubricación y refrigeración. Con el objetivo de solucionar estos problemas dos diseños de chumaceras fueron realizados: uno con refrigeración en la caja y otro con refrigeración en la teja, ambos usando un sistema de sellado. Análisis por Elementos Finitos del comportamiento mecánico y térmico de los diseños garantiza un buen desempeño en operación. Abstract in english The bronze bearings currently used in sugar cane mills undergo an excessive wear due to both, the extraneous matter entering in the bearing gap when the shaft lift by effect of cane passing through the mill and heating caused by failures in both the lubrication and the refrigeration systems. In orde [...] r to solve this problems two bearing were designed: one cooled in the box and other cooled in the roofing tile, both using a sealing system. Finite Elements Analysis of the designs showed that they will have a good mechanical and thermal performance.

Walter, Mora Perdomo; John Sandro, Rivas Murillo; John Jairo, Coronado Marín.

83

Evolution of artificial defects during shape rolling  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Very often defects are present in rolled products. For wire rods, defects are very deleterious since the wire rods are generally used directly in various applications. For this reason, the market nowadays requires wire rods to be completely defect-free. Any wire with defects must be rejected as scrap which is very costly for the production mill. Thus, it is very important to study the formation and evolution of defects during wire rod rolling in order to better understand and minimize the pro...

2007-01-01

84

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

85

Rolling of microalloyed magnesium sheets  

Energy Technology Data Exchange (ETDEWEB)

This paper described a rolling process for a micro-alloyed zinc-manganese (Zn-Ca-Ag-Mn) magnesium alloy. The micro-alloyed magnesium alloy L1 was investigated in order to achieve a finer grain structure and to avoid normal grain growth during rolling. Rolling parameters included billet temperature; rolls temperature and rolls radius; rolling speed; and lubrication. Standard tensile tests were conducted with the rolled alloy L1 flat specimens at room temperature with a test length of 50 mm and a test width of 12.5 mm. Specimens heat treated at 100 degrees C and 200 degrees C showed good balance of strength and elongation. Elongation increased with increasing heat treatment times. Results of the tests demonstrated that the Zn-Ca-Ag-Mn alloy L1 showed exceptionally high elongations to fracture at room temperatures. A pronounced work hardening regime was also observed. It was concluded that the grain structure of the L1 alloy was not influenced after heat treatments until temperatures reached 350 degrees C for 20 minutes. Significant grain coarsening occurred after preliminary heat treatments of 400 degrees C. 7 refs., 1 tab., 6 figs.

Sotirov, N.; Riemelmoser, F.O.; Kuhlein, M.; Kettner, M. [ARC Leichmetallkompetenzzentrum GmbH, Ranshofen (Austria); Uggowitzer, P.J. [ETH Zurich, Zurich (Switzerland). Dept. of Materials, Laboratory of Metal Physics and Technology; Spencer, K. [Natural Resources Canada, Ottawa, ON (Canada). CANMET Materials Technology Lab

2007-07-01

86

Rolling tool calibration for cold rolling of tubes  

International Nuclear Information System (INIS)

An analysis was made of calibration methods for step-back rolling of tubes from austenitic steels to meet the order of nuclear power for tubes with a high quality of inner surfaces. On the basis of this analysis the optimization criterion chosen was the observance of the constant value of the ratio of wall thickness deformation to the deformation of tube diameter for any length of a tube. A logarithmic function was derived for the shape of the rolling pin. Operating trials showed that rolling instruments of the given design have a favourable effect on the quality of the inner surface of tubes and on the even load of the rolling system in an operating cycle. (Ha)

1986-06-18

87

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

88

Thermal expansion of rolled and extruded uranium  

International Nuclear Information System (INIS)

The authors report the results of their studies of the thermal expansion characteristics of hot- and warm-rolled ?-U plate and hot-extruded pipe. The hot-rolled plate had a high coefficient of thermal expansion (CTE) in the rolling direction and a low CTE in the transverse direction. This trend was reversed in both as-warm-rolled plate and plate that was both warm rolled and annealed. In pipe that was hot extruded at large reduction ratios, it was possible to correlate the CTE for the extrusion, radial and circumferential directions with the CTE for rolling, transverse and normal directions in the hot-rolled plate. (Auth.)

1983-01-01

89

Chirality in Swiss Roll metamaterials  

International Nuclear Information System (INIS)

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 900 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.

2010-07-15

90

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

91

Flow analysis of rolling cylinders  

Energy Technology Data Exchange (ETDEWEB)

Preliminary theoretical analysis has been performed of the torque generated due to an infinite cylinder rolling inside another cylinder with a very small gap. Expression for the torque has been obtained in the reference frame of a moving coordinate system. The results show the effects of various parameters such as the rolling speed, the inner-outer cylinder eccentricity and the fluid viscosity. 13 refs.

Kang, Sang-Wook.

1992-01-06

92

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

93

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

94

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

95

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

96

Development of roll-to-roll hot embossing system with induction heater for micro fabrication  

Science.gov (United States)

In this paper, a hot embossing heating roll with induction heater inside the roll is proposed. The induction heating coil is installed inside a roll that is used as a heating roll of a roll-to-roll (R2R) hot embossing apparatus. Using an inside installed heating coil gives the roll-to-roll hot embossing system a more even temperature distribution on the surface of the heating roll compared to that of previous systems, which used an electric wire for heating. This internal induction heating roll can keep the working environment much cleaner because there is no oil leakage compared to the oiled heating roll. This paper describes the principles and provides an analysis of this proposed system; some evaluation has also been performed for the system. A real R2R hot embossing heating roll system was fabricated and some experiments on micro-pattering have been performed. After that, evaluation has been performed on the results.

Yun, Dongwon; Son, Youngsu; Kyung, Jinho; Park, Heechang; Park, Chanhun; Lee, Sunghee; Kim, Byungin

2012-01-01

97

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...

2013-01-01

98

Roll-to-roll manufacturing of electronic devices  

Science.gov (United States)

Roll-to-Roll (R2R) production of thin film based electronic devices (e.g. solar cells, activematrix TFT backplanes & touch screens) combine the advantages of the use of inexpensive, lightweight & flexible substrates with high throughput production. Significant cost reduction opportunities can also be found in terms of processing tool capital cost, utilized substrate area and process gas flow when compared with batch processing systems. Nevertheless, material handling, device patterning and yield issues have limited widespread utilization of R2R manufacturing within the electronics industry.

Morrison, N. A.; Stolley, T.; Hermanns, U.; Kroemer, U.; Reus, A.; Lopp, A.; Campo, M.; Landgraf, H.

2012-03-01

99

Sheet production using powder rolling of nickel and titanium alloys  

International Nuclear Information System (INIS)

Based on information contained in literature, patents and catalogs a review is presented of powder-rolling metallurgy abroad. Statistics are given on the output of powder metallurgy in several countries. In the USA both the dense type of rolled metal for manufacturing various machine parts and the porous variety for making filters are produced. Four main types of technological processes are analysed: the usual flow chart for cold rolling, rolling of preheated powder, rolling in free-flowing state, and rolling with heated rollers. Of these four processes the first is most widely used. Fowders consisting of spherical particles (heat-stable alloys from nickel or high titanium alloys), which are difficult to work with, have not yet found wide practical application in powder metallurgy abroad. Literature data show that granulated heat-resistant alloys can be cold-treated under pressure only after they are powdered. The best methods for pulverizing are: cold-stream granulation and grinding with the aid of vibrational mills. Vacuum rolling of powders and rolling with electrically preheated rollers are especially promising in rolling powders that are difficult to deform

1975-01-01

100

A contribution to scale growth during hot rolling of steel  

Energy Technology Data Exchange (ETDEWEB)

This work was carried out in context with the development of strip casting by the single-belt process. In this new process the casting is directly connected with hot rolling which must be carried out at lower speed than in conventional hot rolling, to match the casting rate. It is of interest to theoretically study the effect of low rolling speed on operational parameters and materials behaviour, among them scale formation. In the present investigation it is demonstrated that, under the conditions of hot rolling, the oxidation of iron in air is governed by a mixed mechanism involving diffusion in the oxide and transport of molecular oxygen in the gaseous boundary layer. An algorithm has been formulated for the description of the deformation behaviour of the scale in the roll bite. Scale formation was computed for conventional finishing rolling with a seven stand mill and for in-line hot rolling of strip produced by the single-belt process. It is found that the final scale thickness in the single-belt casting/in-line hot rolling process is about twice that in conventional hot rolling, for the same strip thickness behind the last stand. (orig.)

Schwerdtfeger, K.; Zhou, S. [Inst. fuer Metallurgie, Technische Univ. Clausthal, Clausthal-Zellerfeld (Germany)

2003-09-01

 
 
 
 
101

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

102

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

103

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 working-layer were obtained for both of them, but the production cost of the WCP/Fe-C composites roller ring decreased by 50%.

2010-09-15

104

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 Michael; Karnik, Rohit N.

2011-01-01

105

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

2012-01-01

106

Cell sorting by deterministic cell rolling.  

Science.gov (United States)

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. PMID:22327803

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

2012-04-21

107

Modeling Asymmetric Rolling Process of Mg alloys  

International Nuclear Information System (INIS)

Asymmetric deformation during rolling can arise in various ways: difference in the radii, speeds, frictions of the top and bottom rolls. Asymmetric warm rolling processes of magnesium alloys were modeled using a lagrangian incremental approach. A constitutive equation representing flow behaviors of AZ31 magnesium alloys during warm deformation was implemented to the modeling. Various roll speed ratios were introduced to investigate deformation behaviors of the magnesium alloys. Bending and texturing of the strips were examined.

2010-06-15

108

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

109

Rolling on low-rollers  

Energy Technology Data Exchange (ETDEWEB)

The assessment of energy efficient tires compares the designs, performance, and claims by the European manufacturers which include Michelin, Pirelli, Goodyear, Uniroyal, and Dunlop. Results of fuel-saving tires tested on specific cars are briefly summarized. Results at producing fuel-saving economy tires show a 5% reduction in fuel consumption which equates to approximately a 25% drop in tire rolling resistance.

1981-10-29

110

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

111

Intuitive control of rolling sound synthesis  

Digital Repository Infrastructure Vision for European Research (DRIVER)

This paper presents a rolling sound synthesis model which can be intuitively controlled. To propose this model, different aspects of the rolling phenomenon are explored : physical modeling, perceptual attributes and signal morphology. A source-filter model for rolling sounds synthesis is presented with associated intuitive controls.

Conan, Simon; Aramaki, Mitsuko; Kronland-martinet, Richard; Ystad, Solvi

2013-01-01

112

Development of the speed control unit of the hot rolling mill of the brazilian National Steel Company; Desenvolvimento do controle de correcao de velocidade do acabamento do LTQ-2 da CSN  

Energy Technology Data Exchange (ETDEWEB)

This work shows the development of a control system to correct the speed of the tandem hot rolling mill, by utilization of a mathematical model. A more reliable operational performance was reached with the application of this model at a computer set-up level. 4 figs.

Silveira, Aquiles A. da; Dornelas, Francisco C.; Ferreira, Emerson R.; Alves, Sergio C.; Miguez, Antonio C.P.; Brandao, Jose M.M.; Tirello, Jonas [Companhia Siderurgica Nacional, Volta Redonda, RJ (Brazil)

1991-12-31

113

Chloride and sulphate determination in the cold rolling mill emulsion. Iron and Steel Company of Sao Paulo State, Brazil; Determinacao de sulfato e cloreto na emulsao do laminador de tiras a frio Companhia Siderurugica Paulista (COSIPA), SP, Brazil  

Energy Technology Data Exchange (ETDEWEB)

This paper presents the aqueous layer determination of the sulphate and chloride ions in the cold rolling mill emulsion. The results show that this method is reliable up 5,0 mg l for sulphate and 2,0 mg l for chloride. The method performance is very simple and it is been used from routine analysis. 7 tabs., 2 refs.

Aufiero, Alice A.M.; Peters, Patricia S.; Caires, Analia C.P.; Reinoldes, Joao [Associacao Brasileira de Metais (ABM), Sao Paulo, SP (Brazil)

1990-12-31

114

Evaluation on some important force models for cold strip rolling  

Energy Technology Data Exchange (ETDEWEB)

To improve the accuracy of rolling force prediction, some important force models were evaluated through applied computation for cold rolling of low carbon steel and aluminum alloy according to measured data on lab mill. The effects of model structure and three important variables - flow stress, contact length and friction coefficient - on the precision of computed force were quantitatively studied. Flow stress was measured with plane-strain compression test, contact length was based on elastic flattening of work-roll by Hitchcock, and friction-coefficient was determined by rolling strain and numerical iteration. In steel rolling Bland and Ford integration model and Bryant and Osborn algebraic equation are better in accuracy than Ekelund and Parkins. In aluminum rolling all the models produce large deviations {delta}F{sub R} = 10-20% if flow stress, contact length and friction coefficient are determined with the same method as steel rolling. The elastic deformation of aluminum strip is now taken into account for its low elastic modulus. An effective method to determine plastic and elastic contact has been developed in this investigation. The accuracy of force computation is obviously improved for aluminum rolling. (orig.)

Li Guangying; Lagergren, J. [Royal Inst. of Tech. (KTH), Stockholm (Sweden). Dept. of Material Processing

2000-11-01

115

76 FR 35400 - Continuation of Suspended Antidumping Duty Investigation on Certain Hot-Rolled Flat-Rolled Carbon...  

Science.gov (United States)

...Investigation on Certain Hot-Rolled Flat-Rolled Carbon-Quality...agreement: --Alloy hot-rolled steel products in which...2300 and higher. --Ball bearing steels, as defined...400, USS AR 500). --Hot-rolled steel coil which...

2011-06-17

116

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

2010-12-01

117

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 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

118

Studentsâ Conceptions About Rolling In Multiple Contexts  

Science.gov (United States)

Research has shown that students have several misconceptions about rotational motion and rolling. Students often do not understand the relationship between the speeds of various points on a rolling wheel. They also do not understand the relationship between the translational and rotational speeds of a wheel that rolls without slipping. We conducted a study to extend existing research on this topic. Specifically, we explored the reasoning resources that students used with regard to rolling without slipping in three different contexts: a single rolling bicycle wheel, a horizontal plank pushed forward on a rolling drum, and two differently sized wheels in a penny-farthing bicycle. We explored the reasoning resources used by students in two different introductory physics classes at two Midwestern universities. We describe studentsâ reasoning resources about rolling in these different contexts.

Rebello, N. S.; Rebello, Carina M.

2013-07-12

119

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.)

2010-05-01

120

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 ...

2006-01-01

 
 
 
 
121

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

122

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; Winther, G.

2004-01-01

123

Generalized Slow Roll for Tensors  

CERN Document Server

The recent BICEP2 detection of degree scale CMB B-mode polarization, coupled with a deficit of observed power in large angle temperature anisotropy, suggest that the slow-roll parameter $\\epsilon_H$, the fractional variation in the Hubble rate per efold, is both relatively large and may evolve from an even larger value on scales greater than the horizon at recombination. The relatively large tensor contribution implied also requires finite matching features in the tensor power spectrum for any scalar power spectrum feature proposed to explain anomalies in the temperature data. We extend the generalized slow-roll approach for computing power spectra, appropriate for such models where the slow-roll parameters vary, to tensor features where scalar features are large. This approach also generalizes the tensor-scalar consistency relation to be between the ratio of tensor and scalar sources and features in the two power spectra. Features in the tensor spectrum are generically suppressed by $\\epsilon_H$ relative tho...

Hu, Wayne

2014-01-01

124

THE MEANING OF “TOYOTARYZM” IN IMPROVING OF THE HOT-ROLLED PLATES PRODUCTION PROCESS  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Steel mill and metal plants in Poland are struggling with a crisis in the global market. Option for metal plants in Poland may be methods of organizing production using methods of the Japanese production companies This chapter presents the concepts of "Toyotaryzm" and suggestions improvement of the mill hot-rolled plates by using asymmetric rolling process.

Szklarzyk, Pawe?; Klimecka-tatar, Dorota; Sygut, Piotr

2013-01-01

125

Study Friction Distribution during the Cold Rolling of Material by Matroll Software  

International Nuclear Information System (INIS)

Rolling process is one of the most important ways of metal forming. Since the results of this process are almost finished product, therefore controlling the parameters affecting this process is very important in order to have cold rolling products with high quality. Among the parameters knowing the coefficient of friction within the roll gap is known as the most significant one. That is because other rolling parameters such as rolling force, pressure in the roll gap, forward slip, surface quality of sheet, and the life of work rolls are directly influenced by friction. On the other hand, in rolling calculation due to lake of a true amount for coefficient of friction a supposed value is considered for it. In this study, a new software (Matroll), is introduced which can determine the coefficient of friction (COF) and plot the friction hills for an industrial mill. Besides, based on rolling equations, it offers about 30 rolling parameters as outputs. Having the rolling characteristics as inputs, the software is able to calculate the coefficient of friction. Many rolling passes were performed on real industrial aluminum mill. The coefficient of friction was obtained for all passes. The results are in good agreement with the findings of the other researchers

2007-04-07

126

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

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...

Vig, Asger Laurberg; Ma?kela?, Tapio; Majander, Pa?ivi; Lambertini, Vito; Ahopelto, Jouni; Kristensen, Anders

2011-01-01

127

Adaptive Automatic Gauge Control of a Cold Strip Rolling Process  

Directory of Open Access Journals (Sweden)

Full Text Available The paper tackles with thickness control structure of the cold rolled strips. This structure is based on the rolls position control of a reversible quarto rolling mill. The main feature of the system proposed in the paper consists in the compensation of the errors introduced by the deficient dynamics of the hydraulic servo-system used for the rolls positioning, by means of a dynamic compensator that approximates the inverse system of the servo-system. Because the servo-system is considered variant over time, an on-line identification of the servo-system and parameter adapting of the compensator are achieved. The results obtained by numerical simulation are presented together with the data taken from real process. These results illustrate the efficiency of the proposed solutions.

ROMAN, N.

2010-02-01

128

Calucaltion of waste heat from hot rolled steel coils at SSAB and its recovery  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Hot rolling process is heat input process. The heat energy in hot rolled steel coils can be utilized. At SSAB Strip Product Borlänge when the hot rolled steel coils came out of the hot rolling mill they are at the temperature range of 500°C to 800°C. Heat energy contained by the one hot rolled steel coil is about 1981Kwh whereas the total heat energy for the year 2008 is 230 GWh/year.The potential of heat is too much but the heat dissipation rate is too slow. Different factors on which he...

Yousaf, Naeem

2009-01-01

129

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

130

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

131

Terras: NATO õppuste roll Euroopas kasvab  

Index Scriptorium Estoniae

Kaitseväe juhataja kindralmajor Riho Terrase sõnul suureneb lähiaastatel NATO õppuste roll Euroopas, sest Afganistanis sõdides saadud kogemust on vaja säilitada ning kasutada seda kollektiivkaitse tugevdamiseks

2013-01-01

132

Interactions Between Stably Rolling Leukocytes In Vivo  

CERN Multimedia

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

133

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

134

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

135

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

136

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

137

A lubricant for cold rolling  

Energy Technology Data Exchange (ETDEWEB)

In the composition of a lubricant (Sm) for cold rolling based on glycerin ethers of wastes from the production of sebacic acid (OSK), in order to increase the antifriction and antiscuff properties of the lubricant and to increase the quality of the processed surface, aminoparaffin fluoride (FA) is additionally introduced with the following component content in percent: aminoparaffin fluoride, 5 to 15; glycerin ether of waste from the production of sebacic acid, 85 to 95. The aminoparaffin fluoride additive, having high surface active properties, promotes an improvement in the conditions for cleaning the surface of pipes after deformation before heat treatment. The proposed lubricant is not aggressive with respect to corrosion, since the aminoparaffin fluoride is a corrosion inhibitor. Tests of the proposed lubricants in extracting samples from OKh18N10G brand steel showed that unlike the known lubricant, they have better antifriction properties. The proposed lubricant may be used in more rigid conditions of deformation when rolling pipes from corrosion resistant steel and alloys without under lubricant coatings.

Markov, V.I. Breskina, A.I.; Bychkova, N.F.; Frolova, L.M.; Gudz, L.A.; Kolesnikov, V.N.; Pedan, V.P.; Shcherbak, R.Ya.; Solovyev, V.M.; Tarasenko, V.A.

1982-01-01

138

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  

Science.gov (United States)

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; Gadgil, Alaka S.; Ghole, Vikram. S.; Gore, Sharad D.; Jaafarzadeh, Neemat; Mirkazemi, Roksana

2009-01-01

139

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

140

Dynamics of Entangled Polymeric Fluids in Two-roll Mill studied via Dynamic Light Scattering and Two-color flow Birefringence; 1, Steady flow  

CERN Multimedia

We present the experimental results on a series of high molecular weight, entangled polystyrene solutions subjected to a ``mixed'' shear and elongational flow-type generated in a co-rotating two-roll mill. For steady-flows as well as for start-up of flows from rest, we used two different optical methods to study the dynamics of entangled polymeric fluids: two-color flow birefringence (TCFB) and dynamic light scattering (DLS). Using the TCFB method, we measured the birefringence, $\\Delta n$, and the orientation angle, $\\chi$, of the optic axes in the solution and thereby the generalized viscosity function, $\\eta$ (with the use of stress-optical relations). The DLS method was applied to measure the velocity-gradient, \\gdot, and the flow-type parameter $\\lambda$ for the polymer solutions under flow conditions identical to the TCFB measurements. For low deformation rates the symmetry of the flow-field was reduced with the use of polymeric fluids compared to that seen with a Newtonian fluid. A molecular constituti...

Sanyal, S; Leal, L C; Sanyal, Subrata; Yavich, Dmitry

2000-01-01

 
 
 
 
141

Adsorption of single-strand alkylammonium salts on bentonite, surface properties of the modified clay and polymer nanocomposites formation by a two-roll mill  

International Nuclear Information System (INIS)

The adsorption of tallow alkylammonium salts onto bentonite from the Lopburi province in Thailand, and the effect of surface wettability on the formation of polymer-clay nanocomposites are reported. We looked specifically at octadecyltrimethyl ammonium chloride (S18), a popular member of the tallow alkylammonium salt family. The adsorption of S18 onto the bentonite interlayer can be divided into three distinct stages depending upon the initial concentration of S18. These stages are (a) monolayer formation, (b) intermediate state of double layer formation and (c) double layer formation. A decrease in surface energy driven by drops in the values of the polar and dispersive components was observed as the amount of surfactant surface coverage increased. Using thermal gravimetric analysis (TGA), the critical surface energy (CSE) of organoclay was found to decrease as the amount of absorbed S18 increased. S18 organoclay with different degrees of surface coverage was used in a two-roll mill to prepare high-density polyetheylene (HDPE)-clay nanocomposites. The oxidized polyethylene wax (OWax) was used as a dispersing agent to promote the delamination of the organoclay platelets. The results from X-ray diffraction (XRD) and transmission electron microscope (TEM) indicated a difference in the dispersing capability of the organoclay.

2010-10-01

142

Study on anaerobic treatment of hazardous steel-mill waste rolling oil (SmWRO) for multi-benefit disposal route.  

Science.gov (United States)

Steel-mill waste rolling oil (SmWRO) is considered as hazardous substance with high treatment and disposal fees. Anaerobic process could not only transform the hazardous substance into activated sludge, but also generate valuable biogas. This study aimed at studying the biochemical methane potential of SmWRO under inoculum to substrate VS ratios (ISRs) of 0.25, 0.5, 1, 1.5, 2 and 3 using septic tank sludge as inoculum in mesophilic and thermophilic conditions, with blank tests for control. Specific biogas yield (mL/g VS(added)), net biogas yield (mL/g VS(removed)) and VS removal were analyzed. The ANOVA results indicated great influence of ISR and temperature on studied parameters. ISR of 1.5 at 55°C and ISR of 1.5 and 2 at 35°C were suggested with the highest specific biogas yield (262-265 and 303mL/g VS(added)). Kinetic analysis showed that Gompertz model fit the experimental data best with the least RMSE and largest R(2). PMID:24212130

Ma, Huanhuan; Li, Zifu; Yin, Fubin; Kao, William; Yin, Yi; Bai, Xiaofeng

2014-01-01

143

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

Science.gov (United States)

... false Enriched bread, rolls, and buns. 136.115 Section 136.115 Food...115 Enriched bread, rolls, and buns. (a) Each of the foods enriched bread, enriched rolls, and enriched buns conforms to the definition and...

2009-04-01

144

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.

2009-08-12

145

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

146

Rolling maneuver load alleviation using active controls  

Science.gov (United States)

Rolling Maneuver Load Alleviation (RMLA) was demonstrated on the Active Flexible Wing (AFW) wind tunnel model in the LaRC Transonic Dynamics Tunnel. The design objective was to develop a systematic approach for developing active control laws to alleviate wing incremental loads during roll maneuvers. Using linear load models for the AFW wind-tunnel model which were based on experimental measurements, two RMLA control laws were developed based on a single-degree-of-freedom roll model. The RMLA control laws utilized actuation of outboard control surface pairs to counteract incremental loads generated during rolling maneuvers and roll performance. To evaluate the RMLA control laws, roll maneuvers were performed in the wind tunnel at dynamic pressures of 150, 200, and 250 psf and Mach numbers of .33, .38, and .44, respectively. Loads obtained during these maneuvers were compared to baseline maneuver loads. For both RMLA controllers, the incremental torsion moments were reduced by up to 60 percent at all dynamic pressures and performance times. Results for bending moment load reductions during roll maneuvers varied. In addition, in a multiple function test, RMLA and flutter suppression system control laws were operated simultaneously during roll maneuvers at dynamic pressures 11 percent above the open-loop flutter dynamic pressure.

Woods-Vedeler, Jessica A.; Pototzky, Anthony S.

1992-01-01

147

Molecular rolling friction: the cogwheel model  

Energy Technology Data Exchange (ETDEWEB)

With the help of a two-dimensional (2D) model we study rolling lubrication by circular ('2D fullerenes') molecules for a wide range of parameters. The conditions under which microscopic rolling friction may be effective are identified and related to the relative ingraining between substrate and molecule, the latter behaving as a nanosized cogwheel.

Braun, O M [Institute of Physics, National Academy of Sciences of Ukraine, 03028 Kiev (Ukraine); Tosatti, Erio [International School for Advanced Studies (SISSA), Via Beirut 2-4, I-34014 Trieste (Italy)], E-mail: obraun@iop.kiev.ua

2008-09-03

148

Rolling of 316L Stainless Steel with Rough Rolls to Potentially Obtain Superficial Nanograins  

Science.gov (United States)

316L stainless steel plates of 5-mm thickness, normalized at 900 °C, were cold rolled with different reductions and number of passes using rolls with three different surface roughnesses: grain heights of 0.17 and 0.33 mm and rhomboid-shaped grains of 1.5-mm height. Subsequently, the rolled samples were annealed at 275 °C for 1 h in an effort to achieve superficial nanograins. The plates laminated using low-roughness rolls had continuous superficial microcrystallization when they were rolled for at least 26 passes. For samples made with rougher rolls, the recrystallized superficial grains formed on the surface (sized ~10-15 ?m) were smaller than those below the surface; this behavior was caused by the major deformation induced by repeated indentations. The superficial recrystallization of the sample also tended to be more continuous for higher number of passes; micrographs of the penetration profiles of indentation in the samples rolled with high-roughness rolls revealed that a sample rolled 24 times had not yet reached the steady surface topology. As a conclusion, in order to successfully form superficial nanograins, very low-roughness rolls must be used as well as a small absolute reduction per pass, followed by annealing. These rolling conditions generate a continuous field of highly superficial deformations, which act as nucleation centers for nanograins during annealing.

Camurri, Carlos; Gallegos, Alejo; Carrasco, Claudia

2014-04-01

149

Rolling of 316L Stainless Steel with Rough Rolls to Potentially Obtain Superficial Nanograins  

Science.gov (United States)

316L stainless steel plates of 5-mm thickness, normalized at 900 °C, were cold rolled with different reductions and number of passes using rolls with three different surface roughnesses: grain heights of 0.17 and 0.33 mm and rhomboid-shaped grains of 1.5-mm height. Subsequently, the rolled samples were annealed at 275 °C for 1 h in an effort to achieve superficial nanograins. The plates laminated using low-roughness rolls had continuous superficial microcrystallization when they were rolled for at least 26 passes. For samples made with rougher rolls, the recrystallized superficial grains formed on the surface (sized ~10-15 ?m) were smaller than those below the surface; this behavior was caused by the major deformation induced by repeated indentations. The superficial recrystallization of the sample also tended to be more continuous for higher number of passes; micrographs of the penetration profiles of indentation in the samples rolled with high-roughness rolls revealed that a sample rolled 24 times had not yet reached the steady surface topology. As a conclusion, in order to successfully form superficial nanograins, very low-roughness rolls must be used as well as a small absolute reduction per pass, followed by annealing. These rolling conditions generate a continuous field of highly superficial deformations, which act as nucleation centers for nanograins during annealing.

Camurri, Carlos; Gallegos, Alejo; Carrasco, Claudia

2014-06-01

150

TR-I rocket roll control system  

Science.gov (United States)

A test rocket designated as TR-I was launched to acquire engineering design data for H-II, the Japanese next-generation satellite launcher, which has been under development by NASDA. A simple roll control system has been installed to the TR-I in order to maintain roll angle and roll rate within a limitation during the flight for assuring complete downlink of the telemetry system and for simulating flight conditions of the H-II. Major components of the roll control system, such as the Electronics Package (E-PACK), Inertial Sensor Package (ISP), Solid Motor Roll Control Unit (SMRC), and their hardware-in-the-loop (HWIL) simulation are discussed, referring to the actual flight data.

Kouchiyama, Jiro; Funo, Yasuhiro; Ogawa, Shigeyuki; Fujiwara, Teruo; Nishida, Megumu; Hasegawa, Kazuo

151

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

Science.gov (United States)

...2120-AA64 Airworthiness Directives; Rolls-Royce Deutschland Ltd & Co KG (Formerly Rolls-Royce Deutschland GmbH, Formerly BMW Rolls-Royce GmbH) Turbofan Engines AGENCY: Federal Aviation Administration (FAA), DOT. ACTION: Notice of proposed...

2013-11-19

152

Vibrations of a rolling tyre  

Science.gov (United States)

We investigate vibrations of an unloaded and loaded tyre rolling at constant speed without slipping in the contact area. A previously proposed analytical model of a reinforced tyre is considered. The surface of the tyre is represented by flexible tread, combined with parts of two tori (sidewalls of the tyre). The contact between the wheel and the ground plane occurs by the part of the tread. The natural frequencies (NF) and mode shapes (MS) are determined analytically for unloaded tyre and numerically for loaded tyre. The results were compared with experiments for the non-rotating tyre. In the case of loaded rotating tyre, the increasing of the angular velocity of rotation implies that NF decrease. Moreover, a phenomenon of frequency loci veering is visible here: NF as functions of angular velocity approach each other and then veer away instead of crossing. The MS interact in veering region and, as a result, interchange.

Kozhevnikov, I. F.

2012-03-01

153

Tensile mechanical behavior and fracture toughness of MWCNT and DWCNT modified vinyl-ester/polyester hybrid nanocomposites produced by 3-roll milling  

International Nuclear Information System (INIS)

This study aims to investigate the tensile mechanical behavior and fracture toughness of vinyl-ester/polyester hybrid nanocomposites containing various types of nanofillers, including multi- and double-walled carbon nanotubes with and without amine functional groups (MWCNTs, DWCNTs, MWCNT-NH2 and DWCNT-NH2). To prepare the resin suspensions, very low contents (0.05, 0.1 and 0.3 wt.%) of carbon nanotubes (CNTs) were dispersed within a specially synthesized styrene-free polyester resin, conducting 3-roll milling technique. The collected resin stuff was subsequently blended with vinyl-ester via mechanical stirring to achieve final suspensions prior to polymerization. Nanocomposites containing MWCNTs and MWCNT-NH2 were found to exhibit higher tensile strength and modulus as well as larger fracture toughness and fracture energy compared to neat hybrid polymer. However, incorporation of similar contents of DWCNTs and DWCNT-NH2 into the hybrid resin did not reflect the same improvement in the corresponding mechanical properties. Furthermore, experimentally measured elastic moduli of the nanocomposites containing DWCNTs, DWCNT-NH2, MWCNTs and MWCNT-NH2 were fitted to Halphin-Tsai model. Regardless of amine functional groups or content of carbon nanotubes, MWCNT modified nanocomposites exhibited better agreement between the predicted and the measured elastic moduli values compared to nanocomposites with DWCNTs. Furthermore, Transmission Electron Microscopy (TEM) and Scanning Electron Microscopy (SEM) were used to reveal dispersion state of the carbon nanotubes within the hybrid polymer and to examine the CNT induced failure modes that occurred under mechanical loading, respectively. Based on the experimental findings obtained, it was emphasized that the types of CNTs and presence of amine functional groups on the surface of CNTs affects substantially the chemical interactions at the interface, thus tuning the ultimate mechanical performance of the resulting nanocomposites.

2009-10-15

154

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

155

Rolled dry lean concrete gravity dam  

Energy Technology Data Exchange (ETDEWEB)

Concrete gravity dam construction is at best a semi-continuous operation, the essential principles of which have advanced little from those established in the 1930s. Construction in rolled Dry Lean Concrete (DLC), a variant of concrete peculiarly suited to mechanized handling, placing and compacting techniques adapted from embankment dam practice, offers the advantage of continuous and economic construction. The concept of the rolled DLC gravity dam is discussed, and recent research into the engineering characteristics of DLC and DLC dam profiles are described. Comparative cost studies for rolled DLC construction are summarized.

Moffat, A.I.B.; Price, A.C.

1978-07-01

156

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

157

Fatigue crack growth and fracture mechanics analysis of a working roll surface layer material  

Directory of Open Access Journals (Sweden)

Full Text Available Fatigue crack growth and fracture mechanics analysis of a working roll surface layer material is presented in this paper. The research is done on a hot strip mill working roll where High Chromium Steel is used for roll’s shell material. To obtain corresponding parameters, a rectangular single edge notched bend specimens – SENB, according to standard BS 7448, were used. The fatigue crack growth analysis was done on a resonant testing machine with use of special crack gauges, while for fracture mechanics parameters the electro–mechanical testing machine was used.

M. Drobne

2014-10-01

158

21 CFR 136.110 - Bread, rolls, and buns.  

Science.gov (United States)

...2009-04-01 false Bread, rolls, and buns. 136.110 Section 136.110 Food...Products § 136.110 Bread, rolls, and buns. (a) Bread, white bread, and rolls, white rolls, or buns, and white buns are the...

2009-04-01

159

An oil for cold rolling of metal  

Energy Technology Data Exchange (ETDEWEB)

The oil for cold rolling of metals (MKhI) is made by adding 0.01 to 10 percent of one or several salts of fatty acids (ZhK) to a base oil (BM). The base oil is either petroleum or vegetable oil, fatty acids, synthetic ethers and so on. Laurates, palmitates, oleates and stearates of beryllium, sodium, magnesium, aluminum, calcium, manganese, iron, copper, zinc and barium are used as the salts. The oil for cold rolling of metal may contain salts of fatty acids obtained with the break down of vegetable oils and fats, saturated and unsaturated fatty acids, polymerized fatty acids, anion active and nonanion active emulsifiers and additives which improve the load capacity of the oil, antioxidants and so on. The oil for cold rolling of metal prevents the adhesion of the steel sheets rolled by a cold method in the process of annealing without the loss of the surface properties of the sheel sheet.

Ito, K.; Kendzi, K.; Onisi, M.

1982-08-27

160

Statistics of remote roll angle measurement.  

Science.gov (United States)

Remote measurement of object orientation is used in various scientific fields, such as robotics, optics, and biology (e.g., optical tweezers). Roll angle is one of the three angles that describe the orientation of an object in space. A common method to measure the roll angle is based on analyzing the polarization of the backreflection of a beam. The accuracy of the measurement is degraded by low signal-to-noise ratio (SNR). The low SNR is the result of the large distance between the measurement device and the object, or due to the small backreflection cross section. We perform a laboratory experiment and derive a mathematical model for the probability density function of the measured roll angle and its expectation value. This model makes it possible to calculate the accuracy of the roll angle measurement at low SNRs. Experiments and theoretical analysis using our model were performed and good agreement between the two approaches has been found. PMID:24787415

Plosker, Effie; Arnon, Shlomi

2014-04-10

 
 
 
 
161

Evaluation of Gears Manufactured by Roll Forming.  

Science.gov (United States)

The purpose of the research effort was to evaluate the fatigue strengths of spur gears produced by two representative roll-forming processes in comparison with those manufactured by conventional forging methods. The two forming processes tested included r...

H. K. Frint

1972-01-01

162

CSR- spelar det någon roll för kunden?  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Sammanfattning Inledning och syfte: Allt fler företag väljer idag att förmedla sitt sociala ansvarstagande till sina kunder eftersom kunder utger sig för att vara intresserade av denna information. Problematiken med de undersökningar som tyder på att CSR spelar en viktig roll för kunderna svarar på hur kunderna vill framstå istället för hur dom faktiskt agerar. Denna undersökning syftar till att förstå vilken roll CSR egentligen spelar för kunden genom att undersöka hur kunder...

Strinnholm, Anna; Attersand, Sofia

2007-01-01

163

A few riddles behind Rolle's theorem  

Digital Repository Infrastructure Vision for European Research (DRIVER)

First year undergraduates usually learn about classical Rolle'stheorem which says that between two consecutive zeros of a smooth univariate function $f$, one can always find at least one zeroof its derivative $f^\\prime$. In this paper, we study a generalization of Rolle's theorem dealing with zeros of higherderivatives of smooth univariate functions enjoying a natural additional property. Namely, we call a smooth function whose $n$th derivative does not vanish on some interval $I\\subseteq \\bR...

Shapiro, Boris; Shapiro, Michael

2012-01-01

164

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

165

Rolling and sliding dynamics in centrifugal spreading  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Centrifugal forcing is a usual method to spread a granular material. The dynamics of a particle in this system appears to change spectacularly according to the shape of the particle. The authors present a dynamical transition between rolling and sliding regime and a purely sliding regime as a function of the friction coefficient and the elongation of the particle. This rolling/sliding motion is indeed observed, in situ, for real particles. This simple effect of shape gives a physical interpre...

Rioual, F.; Piron, E.; Tijskens, E.

2007-01-01

166

Scheduling Cutting Process for Large Paper Rolls  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Paper cutting is a simple process of slicing large rolls of paper, jumbo-reels, into various sub-rolls with variable widths based on demands risen by customers. Since the variability is high due to collected various orders into a pool, the process turns to be production scheduling problem, which requires optimisation so as to minimise the final remaining amount of paper wasted. The problem holds characteristics similar one-dimensional bin-packing problem to some extends and ...

Aydin, Mehmet E.; Taylan, Osman

2013-01-01

167

Rolling-circle transposons in eukaryotes  

Digital Repository Infrastructure Vision for European Research (DRIVER)

All eukaryotic DNA transposons reported so far belong to a single category of elements transposed by the so-called “cut-and-paste” mechanism. Here, we report a previously unknown category of eukaryotic DNA transposons, Helitron, which transpose by rolling-circle replication. Autonomous Helitrons encode a 5?-to-3? DNA helicase and nuclease/ligase similar to those encoded by known rolling-circle replicons. Helitron-like transposons have conservative 5?-TC and CTRR-3? termini and do ...

Kapitonov, Vladimir V.; Jurka, Jerzy

2001-01-01

168

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)

1976-07-10

169

Roll motion analysis of deepwater pipelay crane vessel  

Science.gov (United States)

For a large floating vessel in waves, radiation damping is not an accurate prediction of the degree of roll unlike other degrees of freedom motion. Therefore, to get the knowledge of roll motion performance of deepwater pipelay crane vessels and to keep the vessel working safety, the paper presents the relationship between a series of dimensionless roll damping coefficients and the roll response amplitude operator (RAO). By using two kinds of empirical data, the roll damping is estimated in the calculation flow. After getting the roll damping coefficient from the model test, a prediction of roll motion in regular waves is evaluated. According to the wave condition in the working region, short term statistics of roll motion are presented under different wave parameters. Moreover, the relationship between the maximal roll response level to peak spectral wave period and the roll damping coefficient is investigated. Results may provide some reference to design and improve this kind of vessel.

You, Dandan; Sun, Liping; Qu, Zhiguo; Wang, Tao

2013-12-01

170

Rolling Deformations and Residual Stresses of Large Circular Saw Body  

Directory of Open Access Journals (Sweden)

Full Text Available Rolling path squeezes and rolling residual stresses of large diameter circular saw body for wood, generated by rolling pressure from 10 up to 120 bar were examined. X-ray diffraction, Barkhausen noise (BN and Full Width of the peak at a Half Maximum (FWHM (o methods for evaluation of residual stresses were used. Dependencies of a tangential rolling residual stresses inside rolling paths upon rolling pressure p (bar and rolling area A (mm2 were evaluated. The rolling pressure, as large as 60 bar, resulting in the rolling squeeze as high as 0.04 mm2, and, tangential residual compression stresses inside a rolling path, as large as ?TI = ?822 MPa, was considered to be the largest for the practical application.

Boles?aw Porankiewicz

2010-10-01

171

Effects of roll surface deteriorations on scale defect in hot rolling; Netaukan atsuenji no koban scale kizu ni oyobosu roll hadaare no eikyo  

Energy Technology Data Exchange (ETDEWEB)

Roll surface deteriorations and scale deformation behavior in hot rolling are investigated in order to clarity a mechanism of rolling load increase and scale defect formation on using high speed steel roll. Several experiments are conducted; a rolling/sliding friction test at elevated temperature and model rolling tests for the sheet coil and plate by using high Cr cast iron and high speed steel as roll material. The results obtained are as follows; (1) Worn surface of high Cr cast iron is fat and smooth in hot rolling. On the other hand, fine asperities are formed on worn surface of high speed steel. It is found that this peculiar topography of high speed steel consists of MC carbides which are left by prior wear of matrix in roll microstructure and black oxide film which prevent MC carbides from removing from worn surface, which leads higher friction coefficient and higher rolling load. (2) Fine asperities cause scale heterogeneous deformation of the steel products in roll bite, resulting in scale defect. (3) Heterogeneous scale deformation is easily occurs under conditions with the large oxide film on the steel before rolling and the large reduction in thickness and the high rolling temperature. (author)

Toto, K.; Okada, H.; Sasaki, T.; Koide, T. [Sumitomo Metal Industries, Ltd., Osaka (Japan)

1998-12-01

172

Defect Analysis of Roll-to-Roll SAIL Manufactured Flexible Display Backplanes.  

Science.gov (United States)

HP and Phicot have made the world's first roll-to-roll (R2R) manufactured active matrix displays. Currently we are developing a wrist-worn solar powered display for the U.S. Army. As we scale from research to preproduction on our 1/3 meter wide pilot line...

A. Jeans C. Taussig M. Jam R. E. Elder W. B. Jackson

2011-01-01

173

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 hâ??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

174

Decision Support for the Rolling Stock Dispatcher  

DEFF Research Database (Denmark)

Real-time recovery is receiving a fast growing interest in an increasingly competitive railway operation market. This thesis considers the area of rolling stock dispatching which is one of the typical real-time railway dispatching problems. All work of the thesis is based on the network and planning processes of the railway operator DSB S-tog a/s. In the thesis the problems existing in the railway planning process from the strategic to real-time level are briefly sketched. Network planning, line planning, timetabling, crew and rolling stock planning is outlined and relevant references are given. Specifically the thesis references the operation research studies based on the railway operation of DSB S-tog a/s. Subsequently the process of dispatching is outlined with a specific emphasis on rolling stock. The rolling stock recovery problem is the problem of assigning train units to train departures in a disrupted rolling stock schedule so that operation returns quickly to the originally planned schedule. Different network structures and mathematical formulations for the problem are discussed. Based on prior work on network structures a decomposed approach for the rolling stock recovery problem is put forward. The main contributions of the thesis are contained in four papers included as appendices. The papers deal with respectively an analysis of robustness in timetables, the mathematical model behind a decision support tool for reinsertion of a train line, a survey on the dispatching problems of passenger railway transportation and the decomposed solution process of the rolling stock recovery problem. The paper on the robustness analysis has been accepted for submission in the International Journal of Operations Research. Two of the papers have been submitted to journals and are being reviewed. The last paper will be submitted. Furthermore, the work of the two papers on the robustness analysis respectively the reinsertion model have formed the basis of practical projects in DSB S-tog. The applicability of the decomposed process will be further investigated in the future.

Groth, Julie Jespersen

2009-01-01

175

Studying possibilities to improve the functional properties of metallurgical rolls  

Directory of Open Access Journals (Sweden)

Full Text Available 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 tribologicnl propcnics through adji~stmcno~r ~ h cch cinicalcompsizion odand modificat ioll of rhc hcat trcatmcnt. In thc study prcscntcd only t hc carbon comcnt was sliyhtly incrcascd (havingciirhiclc-forming clcmcnts in Y icw rcst~ltingi n thc incrcnse in lcdcburitic carbides. Il owcvcr, !his most nhvious way or improving thcahrasivc wcar rcsisrnncc incrcascs rhc ~brcaot f rolls cracking and ~hcrcforcrc quircs verification using ttlc iracii~rc~ ncchanicsm cthod.Szaziaical analysis of random1 y sclcctcd fcw dozens of rolls havc shown Tor this gradc or cast stccl a trcnd to rcducc thc carbon contcnzby ~ h ~cn :~nurihcturcmr. ilintilining ir at thc lowcr rangc of limirs spccificd by thc standard and not to incrcasc i t . Thc analysis or thc wcnrmcchmism or suriaccs or worn out mlls madc of G2OOCrMoNi 4-3-3 cast stecl allows making suggestions on thc possihilit ics of hcatrrcarmcnt changes, what aEso has hccn prcscnrcd in ~ h pc a p .

Z. Stradomski

2008-03-01

176

Microstructural heterogeneity of forged rolled rings  

Directory of Open Access Journals (Sweden)

Full Text Available 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 heterogeneity has been proven on the cross section of rods and rings under hot rolling and thermal treatment. Non-uniformity in hardness distribution was found on the hot rolled rings’ face surface and cross section. Final products made from rings with heterogeneous properties characterize: difficulties with machining, cracking during surface hardening and decrease of life time. After the process modification, the rings’ microstructure homogeneity and advantageous hardness distribution were obtained.Practical implications: A good quality of final rings after heat treatment is obtained in the case of charge characterized by a uniform pearlitic/ferritic microstructure. After the process technology modification, the rings’ microstructure homogeneity and advantageous hardness distribution were obtained.Originality/value: The minimum processing degree in the rolling of rod products should guarantee obtaining a homogeneous microstructure on the rings cross section and properties which would ensure a good quality and the required functional properties of the final products.

J. Herian

2007-04-01

177

Study of beryllium fracture during hot rolling  

International Nuclear Information System (INIS)

The causes and pattern of destruction made to blanks of technical beryllium during hot rolling have been studied. Rolling was carried out in vacuum of 1-5x10-5 Hg mm within the temperature range of 400-900 deg C with a drafting of 3-40%. The distribution of lines in the flow and the dislocation structure in the origin of deformation and non-contact areas has been studied by the metallographic method. It has been pointed out that the destruction of beryllium during hot rolling in vacuum takes place as a result of cohesion of the pores that have been formed and the emergence of mainline cracks under the effect of residual tensile stresses. When rolling at temperatures below 500 deg C the destruction is characterized by the formation of large number of dislocation cracks in the unfavourably oriented grains. In order to increase the deformability of beryllium it is recommended to decrease the irregularity of deformation with the aid of heating of the rolls, selecting lubricants, using a steel tire around the blank, etc

1977-01-01

178

Development of hot-rolled steel sheet with a high r-value by rolling in ferrite region with lubrication; Onkan junkatsu atsuen ni yoru ko r chi netsuen koban no kaihatsu  

Energy Technology Data Exchange (ETDEWEB)

For hot rolling with lubrication-annealing process possible to eliminate cold rolling process, study was made on the effect of lubrication characteristics on high r-value hot-rolled steel sheets. For production of hot-rolled steel sheets with a specially high r-value equivalent to cold- rolled steel sheets, lubrication in {alpha} region (ferrite) rolling, control of shear aggregate texture formed in steel sheet surface layers, and large reduction of solute carbon during pre-process of rolling are important. The r-value of nearly 1.5 was obtained by hot rolling with lubrication below 5% in forward slip rate using 1% synthetic ester emulsion as lubricant in a laboratory. For realizing these conditions, solution of the following issues is indispensable: development of a lubricant possible to achieve a high lubrication performance in real continuous hot rolling mills, establishment of rolling technology using such a lubricant, and development of a component design method and process for controlling and reducing solute carbon in {alpha} region rolling for compact rolling. 12 refs., 10 figs., 2 tabs.

Hashimoto, S.; Tsukatani, I.; Kashima, T.; Miyoshi, T. [Kobe Steel, Ltd., Kobe (Japan)

1998-04-01

179

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

180

High-sensitivity roll-angle interferometer.  

Science.gov (United States)

A roll-angle interferometer with high sensitivity is presented in this Letter. 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. Changes of the optical path in the interferometric arms caused by roll are differential and converted into phase shift through a particular interferometer system. The interferometric beams are a completely common path for the adoption of the centrosymmetric measurement structure, and the cross talk of the straightness, yaw, and pitch errors is avoided. The dead path is minimized, so the stability and the accuracy of the measurement can be greatly enhanced. The experimental results fit well with the theoretical analysis, and a measurement resolution of sub-microradian is achieved experimentally. PMID:24104824

Le, Yanfen; Hou, Wenmei; Hu, Kai; Shi, Kai

2013-09-15

 
 
 
 
181

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 shipâ??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

182

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

183

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...

1999-01-01

184

Slow Roll Inflation: A Somehow Different Perspective  

CERN Document Server

In this note we point out that, contrary to the standard point of view, slow roll inflation is due to high gravitational friction. We show that the requirement of slow roll coincides with the requirement of a flat scalar field potential in the case of minimally coupled scalar field. In this sense, the search for a successful inflationary theory may be more fruitful by shifting the focus on models with high gravitational friction. We review then a gravitational mechanism, the so called "Gravitationally Enhanced Friction" mechanism, such that high gravitational friction is dynamically generated during inflation allowing even steep (i.e. non-flat) scalar potential to inflate.

Germani, Cristiano

2011-01-01

185

Effect of carbide properties on lubrication characteristics of roll in cold sheet rolling; Reikan atsuen`yo roll no junkatsu tokusei ni oyobosu tankabutsu shoseishitsu no eikyo  

Energy Technology Data Exchange (ETDEWEB)

The effect of rolls made of iron-chromium-carbon alloys and high speed steels on the lubrication characteristics are examined by rolling annealed low carbon steel sheets. Coefficients of friction for reduction in thickness and limit reductions of friction pick up are measured using the simulation testing machine of sliding-rolling type. The relation between the experimental results on the limit reductions on the one hand and carbide type, carbide area and carbide morphology of roll materials on the other is discussed. The conclusion obtained are as follows : (1) The difference of coefficient of friction among roll materials is small in case that surface roughness of roll is constant. (2) The limit reduction of friction pick up has a strong correlation with the carbide mean spacing of roll materials. (3) Controlling the carbide spacing small is effective for prevention of friction pick up. 8 refs., 11 figs., 1 tab.

Azushima, A. [Yokohama National University, Yokohama (Japan). Faculty of Engineering; Jinbo, Y. [Kanto Special Steel Works, Ltd., Kanagawa (Japan)

1995-12-01

186

Wear phenomena of spinning rolls for stone wool production  

Directory of Open Access Journals (Sweden)

Full Text Available Purpose: Purpose of this paper: Results of the study of wear phenomena of cascade spinning rolls during stone wool production process are described.Design/methodology/approach: The study were based on direct process observations, chemical analysis and temperature measurements of basalt lava, metallographic examinations of the spinning rolls deposits.Findings: It was showed that the deposits of spinning rolls are worn in very different way, depending on the roll position in rolls cascade. Predominant wear phenomena are high temperature erosion, molten basalt lava (molten salt corrosion, high temperature corrosion-oxidation, high temperature metal-ceramic abrasion wear, thermal fatigue of the working surface of spinning rolls.Research limitations/implications: The mechanisms of high temperature erosion demands further investigations and detailed studies.Practical implications: The wear resistance of basalt lava spinning rolls can be increased.Originality/value: The mechanisms of surface layer wear of basalt lava spinning rolls were determined.

A. Klimpel

2006-04-01

187

Quantitative Analysis and Design of a Rudder Roll Damping Controller  

Digital Repository Infrastructure Vision for European Research (DRIVER)

A rudder roll damping controller is designed using Quantitative feedback theory to be robust for changes in the ships metacentric height. The analytical constraint due to the non-minimum phase behaviour of the rudder to roll is analysed using the Poisson Integral Formula and it is shown how the design tradeoffs in closed-loop roll reduction can be approximated using this formula before a controller is designed. The robust roll and course keeping controllers designed are then tested using a no...

1998-01-01

188

Quantitative Analysis and Design of a Rudder Roll Damping Controller  

Digital Repository Infrastructure Vision for European Research (DRIVER)

A rudder roll damping controller is designed using Quantitative feedback theory to be robust for changes in the ships metacentric height. The analytical constraint due to the non-minimum phase behaviour of the rudder to roll is analysed using the Poisson Integral Formula and it is shown how the design tradeoffs in closed-loop roll reduction can be approximated using this formula before a controller is designed. The robust roll and course keeping controllers designed are then tested using a no...

2005-01-01

189

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

190

Cosmological rolling solutions of nonlocal theories  

CERN Multimedia

We find cosmological solutions of a nonlocal scalar field equation with cubic or exponential potential. 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

2009-01-01

191

Generalized slow roll for tensor fluctuations  

Science.gov (United States)

The recent BICEP2 detection of degree scale cosmic microwave background (CMB) B-mode polarization, coupled with a deficit of observed power in large angle temperature anisotropy, suggest that the slow-roll parameter ?H, the fractional variation in the Hubble rate per e-fold, is both relatively large and may evolve from an even larger value on scales greater than the horizon at recombination. The relatively large tensor contribution implied also requires finite matching features in the tensor power spectrum for any scalar power spectrum feature proposed to explain anomalies in the temperature data. We extend the generalized slow-roll approach for computing power spectra, appropriate for such models where the slow-roll parameters vary, to tensor features where scalar features are large. This approach also generalizes the tensor-scalar consistency relation to be between the ratio of tensor and scalar sources and features in the two power spectra. Features in the tensor spectrum are generically suppressed by ?H relative those in the scalar spectrum and by the smoothness of the Hubble rate, which must obey covariant conservation of energy, versus its derivatives. Their detection in near future CMB data would indicate a fast roll period of inflation where ?H approaches order unity, allowed but not required by inflationary explanations of temperature anomalies.

Hu, Wayne

2014-06-01

192

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

193

Development of a Rolling Process Design Tool for Use in Improving Hot Roll Slab Recovery  

International Nuclear Information System (INIS)

Lawrence Livermore National Laboratory participated in a U. S. Department of Energy/Office of Industrial Technology sponsored research project 'Development of a Rolling Process Design Tool for Use in Improving Hot Roll Slab Recovery', as a Cooperative Agreement TC-02028 with the Alcoa Technical Center (ATC). The objective of the joint project with Alcoa is to develop a numerical modeling capability to optimize the hot rolling process used to produce aluminum plate. Product lost in the rolling process and subsequent recycling, wastes resources consumed in the energy-intensive steps of remelting and reprocessing the ingot. The modeling capability developed by project partners will be used to produce plate more efficiently and with reduced product loss

2004-01-01

194

Development of a Rolling Process Design Tool for Use in Improving Hot Roll Slab Recovery  

Energy Technology Data Exchange (ETDEWEB)

Lawrence Livermore National Laboratory participated in a U. S. Department of Energy/Office of Industrial Technology sponsored research project 'Development of a Rolling Process Design Tool for Use in Improving Hot Roll Slab Recovery', as a Cooperative Agreement TC-02028 with the Alcoa Technical Center (ATC). The objective of the joint project with Alcoa is to develop a numerical modeling capability to optimize the hot rolling process used to produce aluminum plate. Product lost in the rolling process and subsequent recycling, wastes resources consumed in the energy-intensive steps of remelting and reprocessing the ingot. The modeling capability developed by project partners will be used to produce plate more efficiently and with reduced product loss.

Couch, R; Becker, R; Rhee, M; Li, M

2004-09-24

195

Low band gap polymers for roll-to-roll coated organic photovoltaics. Design, synthesis and characterization  

Energy Technology Data Exchange (ETDEWEB)

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-to-roll 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. (orig.)

Bundgaard, Eva; Hagemann, Ole; Joergensen, Mikkel; Krebs, Frederik C. [Technical Univ. of Denmark, Roskilde (Denmark). Risoe National Lab. for Sustainable Energy

2011-07-01

196

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

197

Rolling bearings in turbocharger applications; Waelzlager in Abgasturboladern  

Energy Technology Data Exchange (ETDEWEB)

Driven by rising fuel costs and further restrictions regarding exhaust emissions, the automotive and truck industries continue to refine and optimize engine systems. The machine element, specifically the rolling bearing, is being utilized more and more in the design of combustion engines. SKF, the leading rolling bearing manufacturer, has developed together with their customers several innovative special rolling bearings. (orig.)

Schweitzer, F. [SKF Oesterreich AG, Steyr (Austria); Adleff, K. [Voith Turbo GmbH und Co. KG, Crailsheim (Germany)

2006-09-15

198

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

Science.gov (United States)

...2009-04-01 2009-04-01 false Enriched bread, rolls, and buns. 136.115 Section...Bakery Products § 136.115 Enriched bread, rolls, and buns. (a) Each of the foods enriched bread, enriched rolls, and enriched...

2009-04-01

199

21 CFR 136.160 - Raisin bread, rolls, and buns.  

Science.gov (United States)

...2010-04-01 2010-04-01 false Raisin bread, rolls, and buns. 136.160 Section...Standardized Bakery Products § 136.160 Raisin bread, rolls, and buns. (a) Each of the foods raisin bread, raisin rolls, and raisin buns...

2010-04-01

200

21 CFR 136.130 - Milk bread, rolls, and buns.  

Science.gov (United States)

...2010-04-01 2010-04-01 false Milk bread, rolls, and buns. 136.130 Section...Standardized Bakery Products § 136.130 Milk bread, rolls, and buns. (a) Each of the foods milk bread, milk rolls, and milk buns...

2010-04-01

 
 
 
 
201

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

1981-09-02

202

21 CFR 136.160 - Raisin bread, rolls, and buns.  

Science.gov (United States)

...2010-04-01 false Raisin bread, rolls, and buns. 136.160 Section 136.160 Food...136.160 Raisin bread, rolls, and buns. (a) Each of the foods raisin bread, raisin rolls, and raisin buns conforms to the definition and...

2010-04-01

203

21 CFR 136.130 - Milk bread, rolls, and buns.  

Science.gov (United States)

...2010-04-01 false Milk bread, rolls, and buns. 136.130 Section 136.130 Food... § 136.130 Milk bread, rolls, and buns. (a) Each of the foods milk bread, milk rolls, and milk buns conforms to the definition and...

2010-04-01

204

Roll compaction and granulation system for nuclear fuel material  

Energy Technology Data Exchange (ETDEWEB)

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.

Goldmann, L.H. Jr.; Holley, C.C.

1981-07-29

205

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

206

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

207

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

208

Thermal analysis in bar and wire rolling. 5. Thermal analysis in hot rolling; Bo senzai atsuen no ondo kaiseki. 5. Thermal analysis in hot rolling  

Energy Technology Data Exchange (ETDEWEB)

Described herein is result of the mal analysis of round oval paths of stand no. 24 in wire rolling, where the analysis is done by the three-dimensional upstream finite element method to accurately grasp temperature changes in the workpiece in bar and wire rolling. The results presented herein include profiles of surface, center and average temperature of the workpiece in the rolling direction, temperature profiles of the roll bite and its vicinity in the rolling direction, temperature profiles of the workpiece in the thickness, circumferential and width directions, temperature and quantity of released heat generated by friction in the contact plane between the workpiece and roll, and profile of relative sliding speed with the roll. It is found that the heat transfer model for the roll and workpiece, which the authors have used for plate rolling, is applicable to wire rolling, and that a complex temperature profile evolves in the section where quantity of heat generated by friction exceeds that of heat released. 8 refs., 13 figs., 2 tabs.

Kiuchi, N.; Yanagimoto, I.; Wakamatsu, E. [The University of Tokyo, Tokyo (Japan). Institute of Industrial Science

1998-02-01

209

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.

Bech, Jakob Ilsted

2014-01-01

210

Investigation into the causes of cracking of 2024 aluminium alloy during rolling operation  

International Nuclear Information System (INIS)

Aluminium alloy 2024 bars cracked during cold rolling to produce strips conforming to T-3 temper designation. The specimens had reduced to 10 mm X 10 mm size by hot rolling rectangular ingots of size 25 mm X 25 mm in 3 passes using the rolling mill. Microscopic studies of the cracked specimens revealed the presence of inclusions on the grain boundaries and in the fracture valleys. Energy dispersive X-ray analysis (EDAX) indicated that inclusions were rich in iron. Fractrogapy of fracture specimens were carried out using both optical scanning electron microscopy which indicated brittle fracture due to the presence of iron inclusions. (author)

1993-01-01

211

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

212

Coupled rolling motion: considering rolling friction in non-holonomic mechanics  

Energy Technology Data Exchange (ETDEWEB)

This paper enlarges an undergraduate student project in non-holonomic mechanics (Janova et al 2009 Eur. J. Phys. 30 1257-69) by considering rolling friction. In the original problem of coupled rolling motion, the agreement of theory and experiment was demonstrated for the initial part of motion with rolling friction being neglected. As expected, the reality is that rolling friction plays a decisive role during the whole experiment. Extending the correspondence of the model to reality by considering rolling friction, in this paper it is demonstrated that the model satisfactorily explains not only the initial part but also the whole period of the motion observed. Together with the original problem, this paper is an interesting demonstration of the influence of rolling friction and its physical modelling for undergraduate physics education. It also demonstrates that a relatively simple theoretical background can be used for describing realistic situations in mechanics and for explaining experimental results. Moreover, this paper itself can be used by physics teachers as an interesting project in theoretical mechanics that may be solved both separately from and as a follow-up project to Janova et al (2009).

Janova, Jitka; Musilova, Jana, E-mail: janova@mendelu.cz [Department of Theoretical Physics and Astrophysics, Faculty of Science, Masaryk University, Kotlarska 2, 611 37 Brno (Czech Republic)

2011-01-15

213

Roll to roll fabrication technologies for optoelectronic and electronic devices and sensors  

Science.gov (United States)

Embedding of optoelectrical, optical, and electrical functionalities into low-cost products like product packages and printed matter can be used to increase their information content. For these purposes, components like displays, photodetectors, light sources, solar cells, battery elements, diffractive optical elements, lightguides, electrical conductors, resistors, transistors, switching elements etc. and their integration to functional modules are required. Also the need of rapid and reliable di-agnostic systems for wellness and healthcare applications is apparent. Today the time from sampling to result can take hours or even several days. In future the target is to analyze the sample within a few minutes for further action. Additionally, the price of the components for low-end products and disposable sensors has to be in cent scale or preferably below that. Therefore, new, cost-effective, and volume scale capable manufacturing techniques are required. Recent developments of liquid-phase processable electrical and optical polymeric, inorganic, and hybrid material inks together with biocompatible materials have made it possible to fabricate functional components by conventional roll-to-roll techniques such as gravure printing on flexible paper and plastic like substrates. In this paper, we show our current achievements in the field of roll-to-roll fabricated electronics, optoelec-tronics and biosensors. With examples of light guiding structures, organic light emitting diodes, biocompatible materials etc., we demonstrate the huge potential of roll to roll fabrication as a low cost mass production technology for future low end electronic products.

Maaninen, A.; Tuomikoski, M.; Kivimäki, L.; Kololuoma, T.; Välimäki, M.; Leinonen, M.; Känsäkoski, M.

2005-09-01

214

Towards roll-to-roll fabrication of electronics, optics, and optoelectronics for smart and intelligent packaging  

Science.gov (United States)

Embedding of optoelectrical, optical, and electrical functionalities into low-cost products like packages and printed matter can be used to increase their information content. These functionalities make also possible the realization of new type of entertaining, impressive or guiding effects on the product packages and printed matter. For these purposes, components like displays, photodetectors, light sources, solar cells, battery elements, diffractive optical elements, lightguides, electrical conductors, resistors, transistors, switching elements etc. and their integration to functional modules are required. Additionally, the price of the components for low-end products has to be in cent scale or preferably below that. Therefore, new, cost-effective, and volume scale capable manufacturing techniques are required. Recent developments of liquid-phase processable electrical and optical polymeric, inorganic, and hybrid materials - inks - have made it possible to fabricate functional electrical, optical and optoelectrical components by conventional roll-to-roll techniques such as gravure printing, embossing, digital printing, offset, and screen printing on flexible paper and plastic like substrates. In this paper, we show our current achievements in the field of roll-to-roll fabricated, optics, electronics and optoelectronics. With few examples, we also demonstrate the printing and hot-embossing capabilities of table scale printing machines and VTT Electronic's 'PICO' roll-to-roll pilot production facility.

Kololuoma, Terho K.; Tuomikoski, Markus; Makela, Tapio; Heilmann, Jali; Haring, Tomi; Kallioinen, Jani; Hagberg, Juha; Kettunen, Ilkka; Kopola, Harri K.

2004-06-01

215

Multi-scale modelling of hot rolled dual-phase steels for process design  

Digital Repository Infrastructure Vision for European Research (DRIVER)

This thesis investigates and models the austenite to ferrite transformation in the hot rolling of two different dual phase steels. The investigation has been carried out in a deformation dilatometer as well as a 4-stand pilot rolling mill. Three different modelling approaches were employed to give different aspects of information and for different applications. Macroscopic kinetics model base on JMAK rate form gives simple overall kinetics information and indicates the appropriate process win...

Suwanpinij, Piyada

2012-01-01

216

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

217

Investigations upon the indefinite rolls quality assurance in multiple regression analysis  

Energy Technology Data Exchange (ETDEWEB)

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 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.

Kiss, I.

2012-11-01

218

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

219

Numerical simulation of wear of basalt lava spinning rolls  

Directory of Open Access Journals (Sweden)

Full Text Available Purpose: of this paper: Results of the study of wear phenomena of cascade spinning rolls during stone woolproduction process are described.Design/methodology/approach: The study was based on direct process observations, chemical analysis andtemperature measurements of basalt lava, metallographic examinations of the spinning rolls deposits. It was showedthat the deposits of spinning rolls are worn in very different way, depending on the roll position in rolls cascade.Findings: Predominant wear phenomena of the fully austenitic Grade 310 deposit of spinning roll no 1 is moltenbasalt lava corrosion-oxidation accompanied by low and high cycle thermal fatigue, high temperature basalt lavaerosion at low velocity of basalt lava stream impinging the working surface at high angle. Predominant wearphenomena of the austenitic-ferritic Grade S32304 deposit of spinning roll no 2 is high temperature basalt lava erosionat very high velocity of lava stream impinging the working surface at high angle what is the cause of much faster wearof then spinning roll no 1. High temperature erosion wear is accompanied by molten basalt lava corrosion-oxidationand low and high cycle thermal fatigue processes. Predominant wear phenomena of the austenitic-ferritic GradeS32304 deposits spinning roll no 3 and roll no 4 is high temperature basalt lava abrasion as sprayed by rolls no 1 andno 2 fibers of solidifying basalt lava impinge the working surface of spinning rolls no 3 and no 4.Research limitations/implications: The mechanisms of high temperature erosion demands further investigationsand detailed studies.Practical implications: The wear resistance of basalt lava spinning rolls can be increased.Originality/value: The mechanisms of surface layer wear of basalt lava spinning rolls were determined.

A. Lisiecki

2006-08-01

220

Loop quantum cosmology and slow roll inflation  

International Nuclear Information System (INIS)

In loop quantum cosmology (LQC) the big bang is replaced by a quantum bounce which is followed by a robust phase of super-inflation. Rather than growing unboundedly in the past, the Hubble parameter vanishes at the bounce and attains a finite universal maximum at the end of super-inflation. These novel features lead to an unforeseen implication: in presence of suitable potentials all LQC dynamical trajectories are funneled to conditions which virtually guarantee slow roll inflation with more than 68 e-foldings, without any input from the pre-big bang regime. This is in striking contrast to certain results in general relativity, where it is argued that the a priori probability of obtaining a slow roll with 68 or more e-foldings is suppressed by a factor e-204.

2010-11-01

 
 
 
 
221

Loop quantum cosmology and slow roll inflation  

Energy Technology Data Exchange (ETDEWEB)

In loop quantum cosmology (LQC) the big bang is replaced by a quantum bounce which is followed by a robust phase of super-inflation. Rather than growing unboundedly in the past, the Hubble parameter vanishes at the bounce and attains a finite universal maximum at the end of super-inflation. These novel features lead to an unforeseen implication: in presence of suitable potentials all LQC dynamical trajectories are funneled to conditions which virtually guarantee slow roll inflation with more than 68 e-foldings, without any input from the pre-big bang regime. This is in striking contrast to certain results in general relativity, where it is argued that the a priori probability of obtaining a slow roll with 68 or more e-foldings is suppressed by a factor e{sup -204}.

Ashtekar, Abhay, E-mail: ashtekar@gravity.psu.ed [Institute for Gravitation and the Cosmos and Physics Department, Penn State, University Park, PA 16802-6300 (United States); Sloan, David, E-mail: sloan@gravity.psu.ed [Institute for Gravitation and the Cosmos and Physics Department, Penn State, University Park, PA 16802-6300 (United States)

2010-11-01

222

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

223

Slipping and Rolling on an Inclined Plane  

CERN Multimedia

In the first part of the article using a direct calculation two-dimensional motion of a particle sliding on an inclined plane is investigated for general values of friction coefficient ($\\mu$). A parametric equation for the trajectory of the particle is also obtained. In the second part of the article the motion of a sphere on the inclined plane is studied. It is shown that the evolution equation for the contact point of a sliding sphere is similar to that of a point particle sliding on an inclined plane whose friction coefficient is $2/7}\\ \\mu$. If $\\mu> 2/7 \\tan\\theta$, for any arbitrary initial velocity and angular velocity the sphere will roll on the inclined plane after some finite time. In other cases, it will slip on the inclined plane. In the case of rolling center of the sphere moves on a parabola. Finally the velocity and angular velocity of the sphere are exactly computed.

Aghamohammadi, Cina; 10.1088/0143-0807/32/4/017

2011-01-01

224

Innovations in Rolling Process of Helical Gears  

Science.gov (United States)

By recent studies at Fraunhofer IWU Chemnitz basic information about the material flow in the rolling process of high gearings have been obtained, which provide the necessary data basis for a systematic adjustment of variable geometry and technology parameters. To use these data as efficiently as possible for subsequent studies a hybrid approach to this problem was chosen. In that case the combination of visioplasticity and FEM simulation. Such a method already used in many fields of manufacturing technologies has advantages in the field of visioplastic evaluated grid determined deformations and strain parameters according to available plastic theories of Huber, Hencky, Levy or v. Mises, which can be directly applied as boundary conditions for subsequent FEM analysis of the marginal zone of the work piece (gear contour). Results of the first qualitative investigations of this material flow analysis represent the basis for future optimized simulation modeling of gear rolling processes.

Neugebauer, R.; Hellfritzsch, U.; Lahl, M.; Schiller, S.; Milbrandt, M.

2011-01-01

225

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

226

Rolling-circle transposons in eukaryotes.  

Science.gov (United States)

All eukaryotic DNA transposons reported so far belong to a single category of elements transposed by the so-called "cut-and-paste" mechanism. Here, we report a previously unknown category of eukaryotic DNA transposons, Helitron, which transpose by rolling-circle replication. Autonomous Helitrons encode a 5'-to-3' DNA helicase and nuclease/ligase similar to those encoded by known rolling-circle replicons. Helitron-like transposons have conservative 5'-TC and CTRR-3' termini and do not have terminal inverted repeats. They contain 16- to 20-bp hairpins separated by 10--12 nucleotides from the 3'-end and transpose precisely between the 5'-A and T-3', with no modifications of the AT target sites. Together with their multiple diverged nonautonomous descendants, Helitrons constitute approximately 2% of both the Arabidopsis thaliana and Caenorhabditis elegans genomes and also colonize the Oriza sativa genome. Sequence conservation suggests that Helitrons continue to be transposed. PMID:11447285

Kapitonov, V V; Jurka, J

2001-07-17

227

Die Rolle des Motorkortex beim motorischen Lernen  

Directory of Open Access Journals (Sweden)

Full Text Available Aktuelle Studien weisen darauf hin, daß der menschliche primäre Motorkortex (M1 auf einem hohen hierarchischen Level operiert und daß der M1 an komplexen Prozessen wie motorischem Lernen beteiligt ist. Die Natur dieser Beteiligung ist aber unbekannt. Es gibt weiters Hinweise darauf, daß der M1 bei der Kodierung elementarer Bewegungsparameter wie Kraft und Bewegungsbeschleunigung aktiv ist. Eine wichtige Rolle könnte der M1 demnach bei lerninduzierten Veränderungen elementarer Bewegungsparameter spielen. In einer Reihe von Experimenten konnten wir nun zeigen, daß der M1 eine übungs- und effektorspezifische Rolle beim motorischen Lernen spielt, die es uns ermöglicht, Kraft und Bewegungsbeschleunigung rasch zu optimieren. Die Resultate bestätigen die Sicht, daß der Motorkortex nicht nur eine starre Output-Zone für Willkürmotorik ist, sondern auf einem hohen hierarchischen Level operiert, um an komplexen Prozessen wie motorischem Lernen spezifisch mitzuwirken. Mögliche Implikationen für Strategien zur Steigerung von motorischem Lernen und Erholung nach Funktionsausfällen werden diskutiert.

Muellbacher W

2001-01-01

228

Extreme chirality in Swiss roll metamaterials  

Energy Technology Data Exchange (ETDEWEB)

The chiral Swiss roll metamaterial is a resonant, magnetic medium that exhibits a negative refractive band for one-wave polarization. Its unique structure facilitates huge chiral effects: a plane polarized wave propagating through this system can change its polarization by 90 deg. in less than a wavelength. Such chirality is at least 100 times greater than previous structures have achieved. In this paper, we discuss this extreme chiral behaviour with both numerical and analytical results.

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

2009-09-16

229

Extreme chirality in Swiss roll metamaterials.  

Science.gov (United States)

The chiral Swiss roll metamaterial is a resonant, magnetic medium that exhibits a negative refractive band for one-wave polarization. Its unique structure facilitates huge chiral effects: a plane polarized wave propagating through this system can change its polarization by 90° in less than a wavelength. Such chirality is at least 100 times greater than previous structures have achieved. In this paper, we discuss this extreme chiral behaviour with both numerical and analytical results. PMID:21832359

Demetriadou, A; Pendry, J B

2009-09-16

230

Rolling Bearing Life Prediction, Theory, and Application  

Science.gov (United States)

A tutorial is presented outlining the evolution, theory, and application of rolling-element bearing life prediction from that of A. Palmgren, 1924; W. Weibull, 1939; G. Lundberg and A. Palmgren, 1947 and 1952; E. Ioannides and T. Harris, 1985; and E. Zaretsky, 1987. Comparisons are made between these life models. The Ioannides-Harris model without a fatigue limit is identical to the Lundberg-Palmgren model. The Weibull model is similar to that of Zaretsky if the exponents are chosen to be identical. Both the load-life and Hertz stress-life relations of Weibull, Lundberg and Palmgren, and Ioannides and Harris reflect a strong dependence on the Weibull slope. The Zaretsky model decouples the dependence of the critical shear stress-life relation from the Weibull slope. This results in a nominal variation of the Hertz stress-life exponent. For 9th- and 8th-power Hertz stress-life exponents for ball and roller bearings, respectively, the Lundberg- Palmgren model best predicts life. However, for 12th- and 10th-power relations reflected by modern bearing steels, the Zaretsky model based on the Weibull equation is superior. Under the range of stresses examined, the use of a fatigue limit would suggest that (for most operating conditions under which a rolling-element bearing will operate) the bearing will not fail from classical rolling-element fatigue. Realistically, this is not the case. The use of a fatigue limit will significantly overpredict life over a range of normal operating Hertz stresses. Since the predicted lives of rolling-element bearings are high, the problem can become one of undersizing a bearing for a particular application.

Zaretsky, Erwin V.

2013-01-01

231

Inflaton potential reconstruction without slow-roll  

CERN Document Server

We describe a method of obtaining the inflationary potential from observations which does not use the slow-roll approximation. Rather, the microwave anisotropy spectrum is obtained directly from a parametrized potential numerically, with no approximation beyond linear perturbation theory. This permits unbiased estimation of the parameters describing the potential, as well as providing the full error covariance matrix. We illustrate the typical uncertainties obtained using the Fisher information matrix technique, studying the $\\lambda \\phi^4$ potential in detail as a concrete example.

Grivell, I J; Grivell, Ian J; Liddle, Andrew R

2000-01-01

232

Boundary Friction on Molecular Lubricants: Rolling Mode?  

CERN Multimedia

A theoretical model is proposed for low temperature friction between two smooth rigid solid surfaces separated by lubricant molecules, admitting their deformations and rotations. 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 the stick-and-slip features and reveals a non-monotonic (mean) friction force {\\it vs} external load

Loktev, V M; Pogorelov, Yu.G.

2003-01-01

233

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...

2007-01-01

234

A Model of Active Roll Vehicle Suspension  

Directory of Open Access Journals (Sweden)

Full Text Available 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.

I. ?ech

2010-01-01

235

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...

2007-01-01

236

A mechanism for ramified rolling circle amplification  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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-...

Beals Thomas P; Smith James H; Nietupski Raymond M; Lane David J

2010-01-01

237

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

2004-04-01

238

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

1978-01-01

239

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 Ã?gidius

2009-01-01

240

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

 
 
 
 
241

Progress toward roll-to-roll processing of inorganic monolithic electrochromic devices on polymeric substrates  

Energy Technology Data Exchange (ETDEWEB)

As electrochromic device (ECD) emerges into the market, the necessity of cost reduction via high-throughput manufacturing is unavoidable. Inorganic monolithic ECD has compatibility in its manufacturing steps, allows continuous processing and hence low-cost ECD. A roll-to-roll (R2R) production is the industrial standard for high-throughput processing and was chosen to synthesize ECD on polymeric substrates. Preliminary success by implementing methods compatible to the aforementioned R2R processing has been achieved; however, continuous test-runs on an R2R machine are still limited. (author)

Widjaja, E.J.; Delporte, G.; Vandevelde, F.; Vanterwyngen, B. [Bekaert Technology Center, NV, Bekaert SA, Bekaertstraat 2, Zwevegem 8550 (Belgium)

2008-02-15

242

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

243

Roll-to-roll gravure with nanomaterials for printing smart packaging.  

Science.gov (United States)

Roll-to-roll (R2R) gravure is considered one of the highest throughput tools for manufacturing inexpensive and flexible ubiquitous IT devices called "smart packaging" in which NFC (near-field communication) transponder, sensors, ADC (analog-to-digital converter), simple processor and signage are all integrated on paper or plastic foils. In this review, we show R2R gravure can be employed to print smart packaging, starting from printing simple electrodes, dielectrics, capacitors, diodes and thin film transistors with appropriate nanomaterial-based inks on plastic foils. PMID:24749427

Jung, Minhun; Kim, Junseok; Koo, Hyunmo; Lee, Wookyu; Subramanian, Vivek; Cho, Gyoujin

2014-02-01

244

Roll Rotation Cues Influence Roll Tilt Perception Assayed Using a Somatosensory Technique  

Digital Repository Infrastructure Vision for European Research (DRIVER)

We investigated how the nervous system processes ambiguous cues from the otolith organs by measuring roll tilt perception elicited by two motion paradigms. In one paradigm (tilt), eight subjects were sinusoidally tilted in roll with the axis of rotation near ear level. Stimulus frequencies ranged from 0.005 to 0.7 Hz, and the peak amplitude of tilt was 20°. During this paradigm, subjects experienced a sinusoidal variation of interaural gravitational force with a peak of 0.34 g. The second mo...

Park, Sukyung; Gianna-poulin, Claire; Black, F. Owen; Wood, Scott; Merfeld, Daniel M.

2006-01-01

245

Low-cost sensor tape for environmental sensing based on roll-to-roll manufacturing process  

Digital Repository Infrastructure Vision for European Research (DRIVER)

We describe the concept of fabricating low-cost sensor tape for fine-grid environmental sensing based on roll-to-roll manufacturing processes. We experiment with constructing sensors and electronic connections with low-cost conductive inkjet printed copper traces. Our first attempt is to fabricate humidity sensors by spin-coating conductive polymer on sensor substrates and integrating the design with an embedded system. The humidity sensor was tested in a two-point probe and exhibits the I-V ...

2012-01-01

246

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

247

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.

Button, Sérgio Tonini.

248

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

249

Cis-trans isomerization of polyacetylene induced by mechanical rolling  

Energy Technology Data Exchange (ETDEWEB)

The influence of mechanical rolling on the ESR spectrum of originally cis-rich polyacetylene is investigated. Rolling decreases the peak-to-peak ESR linewidth, ..delta..H/sub pp/. This phenomenon is supposed to be related to cis-trans isomerization. However, rolling increases only slightly the trans content and the spin susceptibility of the polymer. These observations can be explained by assuming that the rolling induced isomerization preferentially increases the length of the trans segments with unpaired spins. Rolling is less effective than heating in giving rise to isomerization within all-cis segments or in lengthening trans segments with no stable unpaired spins. The behavior of ..delta..H/sub pp/ as a function of trans content in the case of rolling induced isomerization is different from the thermally activated process. The ESR linewidth gives information only about the trans macroradicals and not about the total cis-trans isomer ratio, that used to be employed.

Vancso, G.; Pekker, S.; Egyed, O.; Janossy, A.

1981-01-01

250

Strip casting with fluxing agent applied to casting roll  

Science.gov (United States)

A strip caster (10) for producing a continuous strip (24) includes a tundish (12) for containing a melt (14), a pair of horizontally disposed water cooled casting rolls (22) and devices (29) for electrostatically coating the outer peripheral chill surfaces (44) of the casting rolls with a powder flux material (56). The casting rolls are juxtaposed relative to one another for forming a pouting basin (18) for receiving the melt through a teeming tube (16) thereby establishing a meniscus (20) between the rolls for forming the strip. The melt is protected from the outside air by a non-oxidizing gas passed through a supply line (28) to a sealing chamber (26). A preferred flux is boron oxide having a melting point of about 550.degree. C. The flux coating enhances wetting of the steel melt to the casting roll and dissolves any metal oxide formed on the roll.

Williams, Robert S. (Fairfield, OH); O'Malley, Ronald J. (Miamisburg, OH); Sussman, Richard C. (West Chester, OH)

1997-01-01

251

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

2004-08-02

252

Influences Of Size Effects On The Rolling Of Micro Strip  

International Nuclear Information System (INIS)

Comparison between down-scaled flat rolling experiments of thin round wire and numerical simulation of those experiments have shown that the production process of manufacturing micro strip out of thin round wire is influenced by size effects. From plane strain compression tests, used as a physical simulation of the rolling process it is concluded that second order size effects of mechanical strength cause decreasing resistance to forming with decreasing wire diameters for rolling experiments with 25% and 50% reduction

2007-04-07

253

Die Rolle von ERp57 in der enchondralen Ossifikation  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Vitamin D3 spielt in der Knochenmineralisierung eine wichtige Rolle. Neben dem klassischen nukleären Vitamin D-Rezeptor (VDR) wurde ERp57, für 1,25-(OH)2 Vit D3 beschrieben. In dieser Arbeit wurde die Rolle von ERp57 in der Chondrozytendifferenzierung untersucht. Hierbei konnte gezeigt werden, dass die Matrixvesikel-assoziierte Form von ERp57 für die Entfernung des Rezeptors von der Chondrozytenoberfläche eine untergeordnete Rolle spielt. Zudem wurde eine knorpel-spezifischen ERp57 knoc...

2012-01-01

254

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

255

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...

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

2011-01-01

256

Prediction of Parametric Roll Resonance by Multilayer Perceptron Neural Network  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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 ...

Mi?guez Gonza?lez, M.; Lo?pez Pen?a, F.; Di?az Casa?s, V.; Galeazzi, Roberto; Blanke, Mogens

2011-01-01

257

Anti Roll Tanks in Pure Car and Truck Carriers  

Digital Repository Infrastructure Vision for European Research (DRIVER)

This is a master thesis conducted at KTH Centre for Naval Architecture in collaboration with Wallenius Marine AB. Rolling motions is something that is undesired in all kinds of seafaring. In terms of propulsion resistance, comfort and route planning it would be desirable to reduce these motions. This thesis is an investigation on how different roll stabilising systems affect the performance of an 8000 unit PCTC vessel, special emphasis is put on investigating the performance of anti roll tank...

2009-01-01

258

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.

2011-01-01

259

Behaviour of Surface Defects in Wire Rod Rolling  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Defects are often present in rolled products, such as wire rod. The markets demand for wire rod without any defects has increased. In the final wire rod products, defects originating from the steel making, casting, pre-rolling of billets and during the wire rod rolling can appear. In this work, artificial V-shaped longitudinal surface cracks has been analysed experimentally and by means of FEM. The results indicate that the experiments and FEM calculations show the same tendency except in two...

Filipovic, Mirjana; Eriksson, Conny; O?verstam, Henrik

2006-01-01

260

Eddy Current and Thermal Analysis of Induction Heating Roll  

Energy Technology Data Exchange (ETDEWEB)

The Induction heating is used in various industry and ever-increasing number of applications. The heating roll, which is a kind of induction heating, widely used in curing of coatings and fiber industry. In this paper we analyzed thermal characteristic of induction heating roll by three dimensional eddy-current analysis. Using this analytic results, We could predict the thermal distribution of induction heating roll (author). 4 refs., 9 figs., 2 tabs.

Jang, S. M.; Cho, S. K.; Yoon, I. K.; Jeong, S. S. [Chungnam National University, Taejeon (Korea); Park, H. C.; Son, Y. S. [Korea Institute of Machinery and Materials, Taejeon (Korea)

2002-07-01

 
 
 
 
261

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

262

Roll caster for the three-layer clad-strip  

Directory of Open Access Journals (Sweden)

Full Text Available Purpose: of this paper is to show the characteristics of two kinds of roll casters for three-layer clad strip of aluminium alloys. Moreover, the characteristics of these twin roll casters were compeered with the early type of roll casters for clad strip.Design/methodology/approach: Design was tried to attain the fabrication of the roll casters to cast the three-layers-clad-strip. One caster was an unequal diameter roll caster equipped with a scraper. The scraper was adopted to prevent the mixture of different kinds of melts of the alloys. The scraper was used to cast the clad strip with clear interfaces between each strip. The other caster was a tandem type roll caster assembled from two vertical type twin roll casters. A vertical type of twin roll was mounted on the other vertical type of a twin roll caster.Findings: Three layers of clad strips could be cast by two kinds of the roll casters developed in the present study. The casting speed was 20 m/min. This speed was much higher at the conventional twin roll caster for the aluminium alloys. Each strip of three layers clad strip was connected strictly. The element of clad strip did not peel at the interface by continuous bending. The as-cast clad strip could be cold-rolled. The element of alloys did not mix at the connecting interface of the strips. The casting conditions which affected the connecting of the strips and condition of interface were investigated and shown in this paper.Research limitations/implications: The width of the strip was from 30 mm to 50 mm. The casting of the wide strip was not investigated. The alloy used in the present study was only aluminium alloys. The length of the cast strip was 3 m. The thickness of element strip was from 0.8 mm to 1.5 mm. The difference of the melting temperature of the alloys was within 50°C. The number of the layers was less than three layers.Practical implications: The roll caster invented in the present study can be used for the fabrication of the clad strip. The clad strip is, for example, used for the brazing sheet of the radiator for the automotive industry.Originality/value: There was not a report concerning the roll caster for three layers clad strip. The roll casters for clad strips shown in this paper were of an original process. Especially, the use of the scraper in the roll casting was original.

R. Nakamura

2010-02-01

263

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

264

Qantitative Analysis and Design of a Rudder Roll Damping Controller  

DEFF Research Database (Denmark)

A rudder roll damping controller is designed using Quantitative Feedback Theory to be robust for changes in the ships metacentric height. The analytical constraint due to the non-minimum phase behaviour of the rudder to roll is analysed using the Poisson Integral Formula and it is shown how the design tradeoffs in closed-loop roll reduction can be approximated using this formula before a controller is designed. The robust roll and course keeping controllers designed are then evaluated using a nonlinear simulation.

Hearns, G.; Blanke, M.

1998-01-01

265

Quantitative Analysis and Design of a Rudder Roll Damping Controller  

DEFF Research Database (Denmark)

A rudder roll damping controller is designed using Quantitative feedback theory to be robust for changes in the ships metacentric height. The analytical constraint due to the non-minimum phase behaviour of the rudder to roll is analysed using the Poisson Integral Formula and it is shown how the design tradeoffs in closed-loop roll reduction can be approximated using this formula before a controller is designed. The robust roll and course keeping controllers designed are then tested using a nonlinear simulation.

Hearns, G.; Blanke, M.

1998-01-01

266

Advanced process limits by rolling of helical gears  

Digital Repository Infrastructure Vision for European Research (DRIVER)

A new developed method describes the gear-rolling-process and an alternative pitch design of forming tools. A model was created to analyze rolling processes which determined that in contrast to flat rolling tools, round tools for helical gears need additional kinematic compensation during diameter-related variable pitch forming processes. The new method shows up to a 50% improvement in pitch accuracy and the ability to roll high teeth gears (up to 10 mm in height and a tooth-height-coefficien...

Neugebauer, Reimund; Hellfritzsch, U.; Lahl, M.

2008-01-01

267

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

268

Nonlinear vibrations in a covered roll system with viscoelastic contact  

Science.gov (United States)

A theoretical analysis on the contact vibration problem of a nip rolling system composed with two paper machine rolls is presented. It is modelled at the contact region by a two-degree-of-freedom (DOF) mass-spring-damper system. The rolling contact force in a case of viscoelastic polymer covered roll is formulated by integration of the contact stress. Regenerative chatter effects to the stability of the vibrations are considered. The perturbation technique is applied through the multi-scale method to calculate the nonlinear normal form of the governing equations to determine the stability behavior of the system. The numerical results in time domain are consistent with the bifurcation diagrams.

Yuan, L.; Järvenpää, V.-M.

2009-07-01

269

Convex functions and the rolling circle criterion  

Directory of Open Access Journals (Sweden)

Full Text Available Given 0≤R1≤R2≤∞, CVG(R1,R2 denotes the class of normalized convex functions f in the unit disc U, for which ∂f(U satisfies a Blaschke Rolling Circles Criterion with radii R1 and R2. Necessary and sufficient conditions for R1=R2, growth and distortion theorems for CVG(R1,R2 and rotation theorem for the class of convex functions of bounded type, are found.

G. P. Kapoor

1995-12-01

270

Heat and wear generation for rolling contacts  

Energy Technology Data Exchange (ETDEWEB)

Railway wheels are getting unround due to wear. Since this effect is a long time phenomenon, there is a need for fast algorithms to calculate the wheel-track system and the contact problem including the wear. A point contact model is used which allows a fast calculation of the contact forces. The contact model includes the influence of the temperature, since the temperature distribution does affect the contact forces. A fast algorithm for calculating the temperature and wear distributions within the contact regime for steady rolling is presented. (orig.)

Sextro, W. [Hannover Univ. (Germany). Inst. fuer Mechanik

2001-07-01

271

Rolls-Royce implementing new production system  

Science.gov (United States)

An advanced, integrated manufacturing systems system is being implemented in Rolls-Royce production facilities in order to cut unit production costs by reducing lead times, manning levels and inventories. The topics discussed include the program outline, planned subcontracting, the machining operation that includes isothermal forming of wide-chord hollow blades, carbon fiber production of subsystems including thrust reversers, continuous dress creep feed grinding, the directionally solidified casting facility that can produce single-crystal blades without modification to the casting furnaces, and a robot machining line.

1982-05-01

272

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

273

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 UVâ??vis and IR spectroscopy.

Bundgaard, Eva; Hagemann, Ole

2010-01-01

274

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

275

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

DEFF Research Database (Denmark)

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

2010-01-01

276

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

277

Effect of roll materials on lubricity in cold rolling; Reikan atsuen no junkatsusei ni oyobosu roru zaishitsu no eikyo  

Energy Technology Data Exchange (ETDEWEB)

Using steels already put to practical use such as low Cr steel, die steel, and high-speed steel for rolling materials, the lubricity and anti-seizure properties in cold rolling are investigated with a newly developed lubricating evaluation testing machine. The coefficient of friction and the anti-seizure limit of each roll corresponding to a wide range of changes in the rolling speed and reduction in thickness are obtained using the evaluation test machine. The anti-seizure properties of each roll is evaluated quantitatively by introducing the interfacial temperature calculated from the obtained experimental data, and the relation between the seizing phenomena and roll materials are investigated by analyzing the conditions of the seized portions of the roll using an X-ray microanalyzer. Difference in the friction coefficients of roll materials is small under the conditions of a standardized surface roughness. Carbides on roll surface are effective for inhibiting the growth of seizure, and die and high-speed steels containing comparatively large amount of carbides show excellent anti-seizure properties. 12 refs., 11 figs., 5 tabs.

Azushima, A.; Kaneda, T. [Yokohama National Univ., Yokohama (Japan). Faculty of Engineering; Jinbo, Y. [Kanto Special Steel Works Ltd., Kanagawa (Japan)

1995-01-01

278

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 (< 1 ?m) powders, e.g., fault-gouge and nano-powders, have remained enigmatic. We report here experimental results of a new efficient mechanism for powder lubrication. We conducted friction tests on high-velocity rotary shear apparatus (Reches & Lockner, 2010). Two types of experimental faults were tested: (1) faults made of solid, igneous rocks (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

279

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

280

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

1976-11-01

 
 
 
 
281

Fatigue properties of rolled stainless steels  

Science.gov (United States)

In this present study, rotating bending fatigue tests and compressive tensile fatigue tests had been performed on notched martensitic stainless steel and austenitic stainless steel specimens, respectively. Fatigue limit tests were done on notched non-deformed and notched deformed specimens in order to evaluate the effect of plastic deformation due to roller-working on fatigue behavior of notched deformed specimens. The result showed that according to increase of deformation value on surface layer of martensitic stainless steel specimens from 0, 0.5 and 1.0 mm, the fatigue limit of those specimens also increase to 485, 730 and 800 MPa, respectively. In case of austenitic stainless steel specimen, the fatigue limit of 0, 0.5 and 1.0 mm deformed specimens are 260, 470 and 500 MPa, respectively Fatigue limit of rolled specimens does not linearly increase with increase in plastic deformation value. Hardness number improvement and notch root residual stress are the most responsible in fatigue strength improvement of the rolled specimens.

Iswanto, Priyo Tri; Nishida, Shin-ichi; Hattori, Nobusuke; Kawakami, Yuji

2005-04-01

282

Precision instrumentation for rolling element bearing characterization.  

Science.gov (United States)

This article describes an instrument to measure the error motion of rolling element bearings. This challenge is met by simultaneously satisfying four requirements. First, an axial preload must be applied to seat the rolling elements in the bearing races. Second, one of the races must spin under the influence of an applied torque. Third, rotation of the remaining race must be prevented in a way that leaves the radial, axial/face, and tilt displacements free to move. Finally, the bearing must be fixtured and measured without introducing off-axis loading or other distorting influences. In the design presented here, an air bearing reference spindle with error motion of less than 10 nm rotates the inner race of the bearing under test. Noninfluencing couplings are used to prevent rotation of the bearing outer race and apply an axial preload without distorting the bearing or influencing the measurement. Capacitive displacement sensors with 2 nm resolution target the nonrotating outer race. The error motion measurement repeatability is shown to be less than 25 nm. The article closes with a discussion of how the instrument may be used to gather data with sufficient resolution to accurately estimate the contact angle of deep groove ball bearings. PMID:17411223

Marsh, Eric R; Vigliano, Vincent C; Weiss, Jeffrey R; Moerlein, Alex W; Vallance, R Ryan

2007-03-01

283

Precision instrumentation for rolling element bearing characterization  

International Nuclear Information System (INIS)

This article describes an instrument to measure the error motion of rolling element bearings. This challenge is met by simultaneously satisfying four requirements. First, an axial preload must be applied to seat the rolling elements in the bearing races. Second, one of the races must spin under the influence of an applied torque. Third, rotation of the remaining race must be prevented in a way that leaves the radial, axial/face, and tilt displacements free to move. Finally, the bearing must be fixtured and measured without introducing off-axis loading or other distorting influences. In the design presented here, an air bearing reference spindle with error motion of less than 10 nm rotates the inner race of the bearing under test. Noninfluencing couplings are used to prevent rotation of the bearing outer race and apply an axial preload without distorting the bearing or influencing the measurement. Capacitive displacement sensors with 2 nm resolution target the nonrotating outer race. The error motion measurement repeatability is shown to be less than 25 nm. The article closes with a discussion of how the instrument may be used to gather data with sufficient resolution to accurately estimate the contact angle of deep groove ball bearings

2007-03-01

284

Casting and rolling in one heat  

Energy Technology Data Exchange (ETDEWEB)

In regard of the reduction of energy consumption during the production of steel slabs and strips different charging procedures are of high economic interest. Especially hot and direct charging procedures are used in modern ways of strip production like CSP and strip casting. For simulation of these procedures and their related effects on the microstructure and the mechanical properties of the material, the complete process chain of melting, casting and hot rolling in one heat has been realised in a pilot scale. In this concept process parameters such as temperature over time are controlled during the complete process. By variation of the thermomechanical process parameters the microstructure and the mechanical properties gained in different processing routes can effectively be simulated. This new set-up allows the simulation of the casting and rolling processes not only in a laboratory scale by using conventional compression, tensile and quench tests but now also in a pilot scale. The results will be used as input parameters for FEM simulation. In this paper the set-up of the laboratory facility is described with the measured and controlled parameters. (orig.)

Kopp, R.; Nutzmann, M.; Ziegelmayer, O. [Inst. fuer Bildsame Formgebung, RWTH Aachen (Germany); Bleck, W.; Diederichs, R. [Inst. fuer Eisenhuettenkunde, RWTH Aachen (Germany)

2002-08-01

285

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

286

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

Science.gov (United States)

...Amendment 39-15860 (74 FR 12086, March 23, 2009): Rolls-Royce Deutschland Ltd & Co KG (formerly BMW Rolls-Royce GmbH, formerly BMW Rolls-Royce Aero Engines): Docket No. FAA-2008-0224; Directorate Identifier...

2012-02-21

287

76 FR 36981 - Airworthiness Directives; Rolls-Royce plc RB211-Trent 500 Series Turbofan Engines  

Science.gov (United States)

...2120-AA64 Airworthiness Directives; Rolls-Royce plc RB211--Trent 500 Series...correct this unsafe condition, Rolls Royce have developed a cleaning or replacement...correct this unsafe condition, Rolls Royce have developed a cleaning or...

2011-06-24

288

77 FR 26216 - Airworthiness Directives; Rolls-Royce plc Turbofan Engines  

Science.gov (United States)

...2120-AA64 Airworthiness Directives; Rolls-Royce plc Turbofan Engines AGENCY...directive (AD) that applies to all Rolls-Royce plc (RR) RB211-Trent 875-17...identified in this AD, contact Rolls-Royce plc, Corporate...

2012-05-03

289

77 FR 32007 - Airworthiness Directives; Rolls-Royce plc Turbofan Engines  

Science.gov (United States)

...2120-AA64 Airworthiness Directives; Rolls-Royce plc Turbofan Engines AGENCY...airworthiness directive (AD) for all Rolls-Royce plc (RR) RB211-Trent 800 series...identified in this AD, contact Rolls-Royce plc, Corporate...

2012-05-31

290

77 FR 20508 - Airworthiness Directives; Rolls-Royce plc Turbofan Engines  

Science.gov (United States)

...2120-AA64 Airworthiness Directives; Rolls-Royce plc Turbofan Engines AGENCY...airworthiness directive (AD) for all Rolls-Royce plc (RR) RB211-Trent 875-17...identified in this AD, contact Rolls-Royce plc, Corporate...

2012-04-05

291

77 FR 58762 - Airworthiness Directives; Rolls-Royce plc Turbofan Engines  

Science.gov (United States)

...2120-AA64 Airworthiness Directives; Rolls-Royce plc Turbofan Engines AGENCY...airworthiness directive (AD) for all Rolls-Royce plc (RR) RB211-Trent 875-17...identified in this AD, contact Rolls-Royce plc, Corporate...

2012-09-24

292

78 FR 17300 - Airworthiness Directives; Rolls-Royce plc Turbofan Engines  

Science.gov (United States)

...2120-AA64 Airworthiness Directives; Rolls-Royce plc Turbofan Engines AGENCY...airworthiness directive (AD) for all Rolls-Royce plc (RR) RB211-Trent 553-61...identified in this AD, contact Rolls-Royce plc, Corporate...

2013-03-21

293

77 FR 73268 - Airworthiness Directives; Rolls-Royce plc Turbofan Engines  

Science.gov (United States)

...2120-AA64 Airworthiness Directives; Rolls-Royce plc Turbofan Engines AGENCY...airworthiness directive (AD) for certain Rolls-Royce plc (RR) RB211-Trent 900 series...identified in this AD, contact Rolls-Royce plc, Corporate...

2012-12-10

294

78 FR 11976 - Airworthiness Directives; Rolls-Royce plc Turbofan Engines  

Science.gov (United States)

...2120-AA64 Airworthiness Directives; Rolls-Royce plc Turbofan Engines AGENCY...airworthiness directive (AD) for all Rolls-Royce plc (RR) RB211-524 series...identified in this AD, contact Rolls-Royce plc, Corporate...

2013-02-21

295

78 FR 17297 - Airworthiness Directives; Rolls-Royce plc Turbofan Engines  

Science.gov (United States)

...2120-AA64 Airworthiness Directives; Rolls-Royce plc Turbofan Engines AGENCY...airworthiness directive (AD) for all Rolls-Royce plc (RR) RB211 Trent 500 series...identified in this AD, contact Rolls-Royce plc, Corporate...

2013-03-21

296

77 FR 56760 - Airworthiness Directives; Rolls-Royce plc Turbofan Engines  

Science.gov (United States)

...2120-AA64 Airworthiness Directives; Rolls-Royce plc Turbofan Engines AGENCY...airworthiness directive (AD) for all Rolls-Royce plc (RR) RB211-Trent 800 series...identified in this AD, contact Rolls-Royce plc, Corporate...

2012-09-14

297

78 FR 22180 - Airworthiness Directives; Rolls-Royce plc Turbofan Engines  

Science.gov (United States)

...2120-AA64 Airworthiness Directives; Rolls-Royce plc Turbofan Engines AGENCY...airworthiness directive (AD) for certain Rolls-Royce plc (RR) RB211-Trent 970-84...identified in this AD, contact Rolls-Royce plc, Corporate...

2013-04-15

298

77 FR 2932 - Airworthiness Directives; Rolls-Royce plc (RR) Turbofan Engines  

Science.gov (United States)

...Airworthiness Directives; Rolls-Royce plc (RR) Turbofan Engines AGENCY: Federal...identified in this AD, contact Rolls-Royce plc, Corporate Communications, P.O...Boeing Airplane Company, Rolls-Royce plc, and American Airlines requested that...

2012-01-20

299

THE STUDY OF SCALE FORMATION ON HOT ROLLED INGOTS AND BILLETS  

Directory of Open Access Journals (Sweden)

Full Text Available During the heating for rolling, ingots and billets are affected by the chemical action of the heating atmosphere. Between the heating environment elements and steel components there are taking place chemical reactions initiated at the separation surface that may affect a layer in metal of about a few microns to a few millimeters. The thickness of the affected layer is a function of the environment nature, heated material composition, chemical reaction’s type and kinetics, heating rate and temperature. The aim of this paper is to correlate the oxidation and the decarburization processes during the heating of ingots and billets for rolling. The study was made on ingots and billets rolled at the breakdown mill of the Special Steel Complex, Physics Laboratories from MECHEL Targoviste, Romania. The scope of the study is the analysis of the scale obtained from the rolling mill train in order to obtain specific information that will be used in adjusting the rolling parameters for diminishing the oxidation and decarburization and for recycling the scale in electric furnaces.

GHEORGHE VLAICU

2010-06-01

300

Determination of vehicle rolling resistance and aerodynamic drag  

Energy Technology Data Exchange (ETDEWEB)

The retarding forces on a vehicle are characterized by rolling resistance and aerodynamic drag. These forces determine power requirements for a specified vehicle performance (particularly important for an electric vehicle) and are necessary inputs for any vehicle simulation. Both rolling resistance and aerodynamic drag are determined for a number of vehicles and the testing and data analysis techniques are described.

Lynn, D.K.; McCormick, J.B.; Bobbett, R.E.; Derouin, C.R.; Nachamkin, J.; Kerwin, W.

1979-01-01

 
 
 
 
301

Slow roll inflation in nonminimally coupled theories: hyperextended gravity approach  

Science.gov (United States)

The slow roll approximation is studied for cosmological models in hyperextended scalar-tensor theories of gravity. A procedure to obtain slow roll solutions in nonminimally coupled gravity is outlined and some examples are provided. An integral condition for the functional form of the nonminimal coupling is imposed in order to obtain intermediate inflationary behavior.

Torres, Diego F.

1997-02-01

302

Influence of the Toroidal Roll Pattern on the Sunspot Activity.  

Science.gov (United States)

The latitude distribution of active regions with respect to the toroidal roll pattern was investigated for the period 1978 to 1982. It is shown that the sunspot activity is not concentrated only at the boundaries of rolls. The downdraft at the convergence...

E. Ribes

1988-01-01

303

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

304

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

305

Slow hot rolling in direct linkage with thin slab and strip continuous casting: Effect on the evolution of austenite grain  

Energy Technology Data Exchange (ETDEWEB)

This work was carried out in context with the development of strip casting with the single-belt process. In this new process the hot rolling is performed in-line with considerably lower velocity than in conventional hot rolling. It is of interest to study the effect of low rolling speed on the material properties. Based on a finite element model used to predict the thermomechanical behaviour of the strip in tandem mills, the microstructural evolution of austenite was computed. The parameter studies were carried out over a wide range of volumetric flow rate extending from that in thin slab casting to that in conventional finishing rolling. They demonstrate that the ''slow hot rolling'' can produce a fine grain of austenite. It is found that the final grain size of austenite is about the same for the two processes under the condition that strip thickness behind the last stand is the same. (orig.)

Zhou, S.; Schwerdtfeger, K. [Techn. Univ. Clausthal (Germany). Inst. fuer Metallurgie

2003-12-01

306

Large transient fault current test of an electrical roll ring  

Science.gov (United States)

The space station uses precision rotary gimbals to provide for sun tracking of its photoelectric arrays. Electrical power, command signals and data are transferred across the gimbals by roll rings. Roll rings have been shown to be capable of highly efficient electrical transmission and long life, through tests conducted at the NASA Lewis Research Center and Honeywell's Satellite and Space Systems Division in Phoenix, AZ. Large potential fault currents inherent to the power system's DC distribution architecture, have brought about the need to evaluate the effects of large transient fault currents on roll rings. A test recently conducted at Lewis subjected a roll ring to a simulated worst case space station electrical fault. The system model used to obtain the fault profile is described, along with details of the reduced order circuit that was used to simulate the fault. Test results comparing roll ring performance before and after the fault are also presented.

Yenni, Edward J.; Birchenough, Arthur G.

1992-01-01

307

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

308

Determination of carbon and nitrogen in rolled ferritic steel sheets  

International Nuclear Information System (INIS)

This paper reports texture induced anisotropy of the carbon and nitrogen Snoek relaxation measured in commercial carbon-manganese rolled steel. This phenomenon strongly influences determination of the concentration of C and N atoms dissolved in ferritic steel sheets. The relationship between the height of the Snoek peak and the concentration of foreign interstitial atoms (FIAs) in bbc single crystal is therefore reconsidered in the case of polycrystalline rolled steels. Anisotropy effect is observed in rolled steel sheets as well as in sheets subjected to various heat treatment. In all investigated cases the Snoek peak is observed in samples cut at the angle 45o to the rolling direction (RD) is higher by around 45% than for perpendicularly or transversely cut specimens. Hence this effect is general. Strong anisotropy of the Snoek relaxation in rolled samples is examined by sensitivity of so-called Snoek orientation factor ? to texture components determined by the three-dimensional orientation distribution function ODF. (author)

1998-05-17

309

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

310

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

311

29 CFR 1917.71 - Terminals handling intermodal containers or roll-on roll-off operations.  

Science.gov (United States)

...container or roll-on roll-off terminal for passage of employees to...handling equipment or in the terminal's traffic lanes shall wear...be overloaded. (5) Each tractor shall have all brake air lines...address all conditions in the terminal that could affect the...

2010-07-01

312

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

313

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

Science.gov (United States)

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. PMID:24803196

Liao, Kuan-Hsun; Lo, Cheng-Yao

2014-01-01

314

Roll-to-roll printed resistive WORM memory on a flexible substrate  

International Nuclear Information System (INIS)

The fabrication process and the operation characteristics of a fully roll-to-roll printed resistive write-once-read-many memory on a flexible substrate are presented. The low-voltage (<10 V) write operation of the memories from a high resistivity ‘0’ state to a low resistivity ‘1’ state is based on the rapid electrical sintering of bits containing silver nanoparticles. The bit ink is formulated by mixing two commercially available silver nanoparticle inks in order to tune the initial square resistance of the bits and to create a self-organized network of percolating paths. The electrical performance of the memories, including read and write characteristics, is described and the long-term stability of the less stable ‘0’ state is studied in different environmental conditions. The memories can find use in low-cost mass printing applications. (paper)

2012-08-03

315

Analysis and fabrication of a prism film with roll-to-roll fabrication process.  

Science.gov (United States)

A prism-based brightness enhancement film (BEF), has been investigated through computer-aided optical analysis and experiments in this study. The prism film was fabricated on a 100 microm thick PET film substrate using roll-to-roll (R2R) process with UV curable resins of different refractive indices. The results from both optical analysis and experiments showed that resins with higher refractive indices have better on-axis luminous gain. The prism structures fabricated on the substrate achieved a replication rate of 97.54% in this study. Compared with the 3M BEF, the prism films developed in this study are improved in on-axis luminous gains when the refractive index of the resin is higher than 1.53. PMID:19293901

Wang, Min-Wen; Tseng, Chih-Chin

2009-03-16

316

Large-scale roll-to-roll fabrication of vertically oriented block copolymer thin films.  

Science.gov (United States)

Large-scale roll-to-roll (R2R) fabrication of vertically oriented nanostructures via directed self-assembly of cylindrical block copolymer (c-BCP) thin films is reported. Nearly 100% vertical orientation of cylinders in sub-100 nm c-BCP films under optimized processing via a dynamic sharp temperature gradient field termed Cold Zone Annealing-Sharp or 'CZA-S' is achieved, with successful scale-up on a prototype custom-built 70 ft × 1 ft R2R platform moving at 25 ?m/s, with 9 consecutive CZA units. Static thermal annealing of identical films in a conventional vacuum oven fails to produce comparable results. As a potential for applications, we fabricate high-density silicon oxide nanodot arrays from the CZA-S annealed BCP thin film template. PMID:23647480

Singh, Gurpreet; Batra, Saurabh; Zhang, Ren; Yuan, Hongyi; Yager, Kevin G; Cakmak, Miko; Berry, Brian; Karim, Alamgir

2013-06-25

317

Roll-to-Roll Microimprinting Process for Indium Tin Oxide Layer Patterning  

Science.gov (United States)

Conventional indium tin oxide (ITO) layer patterning processes are problematic because they have limited efficiency. Many applications demand large-area, continuous processing with low costs and a high throughput. In order to overcome these problems, a continuous roll-to-roll (R2R) microimprinting process is proposed and demonstrated for the purpose of ITO layer patterning. Additionally, a series of experiments were conducted to investigate the influence of process parameters, i.e., the operating speed, the nip pressure and the tension of substrate, and the geometry, i.e., the width and height of the master patterns, on the imprinted patterns of ITO-coated polyethylene terephthalate substrates. The proper imprinting conditions are investigated and the mechanism of ITO patterning by imprinting process was suggested. It was found that the ITO-coated area can be electrically isolated through the imprinting process, by the accumulation of microcracks on ITO induced by the deformation.

Ahn, Byoung-Joon; Kim, Ji-Youp; Ko, Sung-Lim

2013-05-01

318

Roll-to-roll printed resistive WORM memory on a flexible substrate  

Science.gov (United States)

The fabrication process and the operation characteristics of a fully roll-to-roll printed resistive write-once-read-many memory on a flexible substrate are presented. The low-voltage (<10 V) write operation of the memories from a high resistivity ‘0’ state to a low resistivity ‘1’ state is based on the rapid electrical sintering of bits containing silver nanoparticles. The bit ink is formulated by mixing two commercially available silver nanoparticle inks in order to tune the initial square resistance of the bits and to create a self-organized network of percolating paths. The electrical performance of the memories, including read and write characteristics, is described and the long-term stability of the less stable ‘0’ state is studied in different environmental conditions. The memories can find use in low-cost mass printing applications.

Leppäniemi, Jaakko; Mattila, Tomi; Kololuoma, Terho; Suhonen, Mika; Alastalo, Ari

2012-08-01

319

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

320

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

 
 
 
 
321

Modeling of rolling element bearing mechanics  

Science.gov (United States)

Roller element bearings provide the primary mechanical interface between rotating and nonrotating components in the high performance turbomachinery of the Space Shuttle Main Engine (SSME). Knowledge of bearing behavior under various loading and environmental conditions is essential to predicting and understanding the overall behavior of turbopumps, including rotordynamic stability, critical speeds and bearing life. The objective is to develop mathematical models and computer programs to describe the mechanical behavior of ball and cylinder roller bearings under the loading and environmental conditions encountered in the SSME and future high performance rocket engines. This includes characteristics such as nonlinear load/motion relationships, stiffness and damping, rolling element loads for life prediction, and roller and cage stability.

Greenhill, L. M.

1991-01-01

322

Thermal transport properties of rolled graphene nanoribbons  

Science.gov (United States)

Using nonequilibrium Green's function method, we investigate the influence of the curvature and edge effects on the thermal transport during the process of rolling graphene nanoribbons (GNRs) into carbon nanotubes (CNTs) in the transverse direction. The curvature effect results in a slight decrease in the thermal conductance of GNRs, which is remarkably different from that in the longitudinal direction. The curvature and edge effects show a strong size and chirality dependence, while the curvature effect is more sensitive to the size. When the size equals to 12.8 nm (49.2 nm) with the zigzag (armchair) edge, the edge effect results in the reduction of thermal conductance of 2.4% (13.0%) as compared to the corresponding CNT, but the curvature effect vanishes.

Li, Dengfeng; Li, Bolin; Luo, Min; Feng, Chunbao; Ouyang, Tao; Gao, Fei

2013-08-01

323

WGHB Open Vault: Rock and Roll  

Science.gov (United States)

Sixty years after it took the world by storm, rock and roll continues to be a vital musical force. It may have branched off into a million little variations, but it remains the subject of documentaries, scholarly volumes, and much more. This collection from the WGBH Open Vault brings together dozens of interviews with rock and rollers from the 1950s to the 1990s. These interviews were originally conducted as part of a co-production between WGBH/Boston and the BBC. All told, there are over 160 interviews here with folks like Ben E. King, Al Kooper, Dick Dale, Kenny Gamble, and Leon Huff. Each video also has a transcript and complete bibliographic information. Visitors can search through interviews by name, date, or media format. Users are encouraged to leave their own comments on the videos as well.

324

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.

Varela López, F.; Rosen, M..

325

Thick backed carbon targets via mechanical rolling  

International Nuclear Information System (INIS)

For targets requiring thick backing foils, the straight-forward and usual method is to deposit the target material directly on the backing by thermal evaporation. In some instances the reverse is more desirable, adding a backing to an already existing target foil, for example. A recent study involving measurement of the lifetime of the first 2+ excited state in 36Ar by the Doppler shift attenuation method required 0.5 mg/cm2 natural carbon targets on thick (18 mg/cm2) gold and lead backings. Problems of delamination had arisen after beam irradiation using thick gold backings for these experiments. Carbon target foils were then prepared by mechanical rolling in direct contact with a thick lead backing using an intermediate layer of indium to assure good adhesion of the layers. Details of the method will be discussed. (author)

2014-02-01

326

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

327

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

328

Energy saving processes in the production of flat rolled steel products. Energieeinsparung bei der Herstellung von Flacherzeugnissen aus Stahl  

Energy Technology Data Exchange (ETDEWEB)

On the medium-wide strip mill of the Thyssen AG in Berlin, milling experiments were carried out with the aim to change the quality of hot-rolled steel in such a way that cold-rolled steels or flat products can be substituted. The application of this hot-rolled steel will make some of the next production and/or heat treatment steps unnecessary, so that the substitution will be connected with energy savings. Apart from low-carbon steel coils of ferritic, highly corrosion-resistant micro-alloyed structural steels and dual-phase steels were manufactured. With the successful closing of the experiments, the aim to save energy has been reached, and hot-rolled steel has been made more competitive.

Angele, B.; Maid, O.

1983-11-01

329

Numerical and Experimental Investigation of Roll Forces and Torques in Cold Roll Forming of a Channel Section  

Science.gov (United States)

One of the most important issues in the review of cold roll forming process of metals is estimation of force and torque. The optimum production line can be designed determining the effective parameters on force and torque. Some of these parameters are material, sheet thickness, bending angle, lubrication conditions, rolls rotational speed and distance of the stands. The aim of this study is to investigate the effect of thickness, yield strength, sheet width and forming angle plate on the force and torque applied on rolls. So the forming process was 3D simulated in finite element software Marc/mentat. Simulation results showed that with increase of yield strength, thickness and forming angle, applied force and torque on rolls will increase. Also the increase in sheet width- assuming constant flange length- will increase the force on the rolls and reduce the torque needed for forming. The effect of thickness and sheet width was experimentally investigated which verified the results obtained by FEA.

Davoodi, B.; Naeini, H. Moslemi; Asl, Y. Dadgar; Azizi T., R.; Kasaei, M. M.; Panahizadeh, V. R.

2011-01-01

330

Allowable variation of cold-rolled strip transverse profiles in high tension  

Science.gov (United States)

The formation mechanism of the cold-rolled strip shape with high tension was studied. An advanced method to calculate the allowable variation of strip transverse profiles was established by the strip buckling criterion, which can be more properly used in cold rolling. With this method, the aim allowable variation of the product strip transverse profile and the required transverse profile range of incoming strips can be reached. Besides, this method has been successfully applied in a domestic tandem cold mill, and the transverse profile range of incoming strips suggested with this method is more practicable and complete. Consequently, the good performance is acquired.

Wang, Xiao-Chen; Yang, Quan; Du, Xiao-Zhong; Jiang, Zheng-Yi

2010-10-01

331

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

2006-09-01

332

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

Science.gov (United States)

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 J5000 better than 1.7 T, using hot rolling conditions 40 mm transfer bar thickness, finish mill entry temperature 1000 °C, and finishing temperature 800-840 °C and after decarburization heat treatment and grain growth treatment, was obtained.

Hu?ady, J.; ?erník, M.; Hilinski, E. J.; Predmerský, M.; Magurová, A.

2006-09-01

333

High-strength nanostructured Al/B{sub 4}C composite processed by cross-roll accumulative roll bonding  

Energy Technology Data Exchange (ETDEWEB)

Highlights: Black-Right-Pointing-Pointer Nanostructured Al/8 vol.% B{sub 4}C composites were produced in the form of sheets. Black-Right-Pointing-Pointer Good bonding was performed between Al layers in the presence of the ceramic particles. Black-Right-Pointing-Pointer The tensile strength of the composite improved by increasing the number of CR-ARB cycle. - Abstract: In the present work, nanostructured Al/B{sub 4}C composites were successfully produced in the form of sheets, through cross roll accumulative roll bonding (CR-ARB) process, at room temperature. The CR-ARB process was performed in two steps. In the first step, the strips were roll-bonded with a draft percentage of 66% reduction and for the next, the strips were roll-bonded with a draft percentage of 50%. The later step is consist of 8 rolling cycles, in which, after every rolling cycle the specimen was rotated 90 Degree-Sign , around normal direction of the rolling process, and then rolled again. The X-ray diffraction peak profile analysis was used to determine the crystallite size of the Al matrix in the various cycles. The results showed that CR-ARB process can effectively refine the coarse-grained structure to an ultrafine grain range, so that the crystallite size of the Al matrix of the composite produced by this process was determined to be about 110 nm. To evaluate microstructure of the produced composites, optical microscope (OM) was used. The results proved that the microstructure of the produced composite has a good degree of homogeneity in particles distribution and also a good bonding created between Al layers. To evaluate mechanical properties of the produced composites, their tensile strength was also determined in various rolling cycles and compared with the same composites produced by conventional accumulative roll bonding (ARB) process.

Alizadeh, Morteza, E-mail: Alizadeh@sutech.ac.ir [Department of Materials Science and Engineering, Shiraz University of Technology, Modarres Blvd., 3619995161, Shiraz (Iran, Islamic Republic of); Paydar, M.H. [Department of Materials Science and Engineering, School of Engineering, Shiraz University, Zand Blvd., 7134851154, Shiraz (Iran, Islamic Republic of)

2012-03-15

334

Studying Cell Rolling Trajectories on Asymmetric Receptor Patterns  

Science.gov (United States)

Lateral displacement of cells orthogonal to a flow stream by rolling on asymmetric receptor patterns presents an opportunity for development of new devices for label-free separation and analysis of cells1. Such devices may use lateral displacement for continuous-flow separation, or receptor patterns that modulate adhesion to distinguish between different cell phenotypes or levels of receptor expression. Understanding the nature of cell rolling trajectories on receptor-patterned substrates is necessary for engineering of the substrates and design of such devices. Here, we demonstrate a protocol for studying cell rolling trajectories on asymmetric receptor patterns that support cell rolling adhesion2. Well-defined, ?m-scale patterns of P-selectin receptors were fabricated using microcontact printing on gold-coated slides that were incorporated in a flow chamber. HL60 cells expressing the PSGL-1 ligand 3were flowed across a field of patterned lines and visualized on an inverted bright field microscope. The cells rolled and tracked along the inclined edges of the patterns, resulting in lateral deflection1. Each cell typically rolled for a certain distance along the pattern edges (defined as the edge tracking length), detached from the edge, and reattached to a downstream pattern. Although this detachment makes it difficult to track the entire trajectory of a cell from entrance to exit in the flow chamber, particle-tracking software was used to analyze and yield the rolling trajectories of the cells during the time when they were moving on a single receptor-patterned line. The trajectories were then examined to obtain distributions of cell rolling velocities and the edge tracking lengths for each cell for different patterns. This protocol is useful for quantifying cell rolling trajectories on receptor patterns and relating these to engineering parameters such as pattern angle and shear stress. Such data will be useful for design of microfluidic devices for label-free cell separation and analysis.

Lee, Chia-Hua; Bose, Suman; Van Vliet, Krystyn J.; Karp, Jeffrey M.; Karnik, Rohit

2011-01-01

335

Clad strip casting by a twin roll caster  

Directory of Open Access Journals (Sweden)

Full Text Available Purpose: Of this paper is to realize the casting of the clad strip by only one process. Therefore, the investigation of the ability of the casting of the clad strip by a vertical type twin roll caster was operated. The aim of the use of the twin roll caster to make clad strip was in the reduction of the production-energy of the clad strip.Design/methodology/approach: Used in the present study was a vertical type twin roll caster with the scriber. The scriber was used to prevent the mixture of the two kinds of the melts. The scriber was set at roll-bite, and the scriber contacted to the one of solidification layer. The melt was stopped by the scriber and the only the solidification layer was dragged by the roll.Findings: The clad strip with the clear interface could be by the vertical type twin roll caster with the scriber. The scriber was useful to drag only the solid and semisolid layer. The two kinds of strips were connected strictly at the interface of the clad strip. The clad strip was not broken at the interface by the continuous bending.Research limitations/implications: Are that 100 mm width-strip was cast in the present study. Ability of the clad strip that is wider than 100 mm was not clear. The control of the clad ratio was not investigated.Practical implications: The twin roll caster devised and investigated in this report is useful to cast clad strip like the brazing sheet for the radiator of the automobile.Originality/value: The vertical type twin roll cater to cast clad strip is original process. The scriber was used to prevent the mixture of the two kinds of melts. The scriber was not used in the previous research to cast clad strip at the twin roll caster, and use of the scriber was the first try.

T. Haga

2009-06-01

336

Topical developments at TMCP-rolled heavy plates; Aktuelle Entwicklungen bei TM-gewalzten Grobblechen  

Energy Technology Data Exchange (ETDEWEB)

The lecture presents topical developments at TMCP-rolled heavy plates for shipbuilding application. There are shown requirements for present-day shipbuilding plates and the subsequently derived different processes of thermomechanical rolling of heavy plates. Based on the plate making process of the rolling mill do Dillinger Huette the metallurgical design and results of the heavy plate production are presented. (orig.) [German] Der Beitrag befasst sich mit aktuellen Entwicklungen bei TM-gewalzten Grobblechen fuer den Schiffbau. Es werden die Anforderungen an moderne Schiffbaustaehle und die daraus abgeleiteten Verfahrensvarianten des thermomechanischen Walzens von Grobblechen dargestellt. Am Beispiel der Prozessfuehrung im Walzwerk der Dillinger Huette werden das metallurgische Design und die Ergebnisse der Grobblechfertigung vorgestellt. (orig.)

Just, C. [Dillinger Huettenwerke AG, Dillingen (Germany)

2002-10-01

337

Graphical Addenda in the Technological Area of the Nodular Iron Cast Rolls Production  

Directory of Open Access Journals (Sweden)

Full Text Available The technical conditions, which are imposed to the cast iron rolls in theexploitation period, are very different and often contradictory. The obtaining of variousphysical and mechanical properties in the different points of the same foundry productmeets difficult technological problems in the industrial condition. One of the parameters,which determine the structure of the irons destined for rolls casting, is the chemicalcomposition. If we not respect this composition, which guaranties the exploitationproperties of the each roll in the stand of rolling mill, it will lead to rejection. Alloyingelements have in principle the same influence on structure and properties. This papersuggest a mathematical interpretation of the influence of the main alloy elements over themechanical characteristics (the hardness on the crust and on the necks of the rolls of thisnodular irons, resulting the average values and average square aberration of the variablesHB, and the main alloying elements (Cr, Ni, Mo, the equations of the hyper surface in thefour dimensional space. For the statistical and mathematical analysis, there were used 23industrial cases. The resulted surfaces, belonging to the three-dimensional space, can berepresented and, therefore, interpreted by technologists. Knowing these level curves allowsthe correlation of the values of the twos independent variables so that the hardness can beobtained in between the requested limits. The paper presents the results of some researchesregarding the chemical composition of the nodular irons destined for casting half-hardrolls. It is presented, in graphical form, used the Matlab area, the influence of the mainalloying elements upon the hardness, and measured on the necks and the core of the rolls,respectively on the working surface (body of these very important rolling mill componentsThe realization of an optimal chemical composition can constitute a technical efficientmode to assure the exploitation properties, the material from which the rolling millscylinders are manufactured having an important role in this sense. From this point of viewis applied the mathematical molding, which is achieved starting from the differentiation onrolls component parts, taking into consideration the industrial data obtained from thehardness mensuration on rolls, which recommends the hardness, for different chemicalcompositions.

Imre Kiss

2008-10-01

338

Cracking phenomena in twin roll strip casting of steel  

Energy Technology Data Exchange (ETDEWEB)

Surface cracking on twin roll cast 0.6%-C steel has been studied. It was shown that cracks are associated with the phenomenon of uneven surface temperature and occur within hot spots or at the boundary between hot and colder zones. Crack orientation is mainly transversal. Thermal fluctuations on the strip surface are probably generated at the initial contact of the solidifying steel shell with a blank roll surface. They can be prevented by shot blasting or coating of the roll surfaces. This also eliminates cracking. (orig.)

Zimmermann, H.; Buechner, A.R.; Tacke, K.-H. [Max-Planck-Inst. fuer Eisenforschung GmbH, Duesseldorf (Germany)

2000-07-01

339

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

340

Heat transfer through rotating roll of contact dryer  

Energy Technology Data Exchange (ETDEWEB)

This paper covers results of experimental and theoretical researches referring to the technique of contact drying. Research of roll system parameters was made in case of lack of drying material layer and in case of existence of drying material layer on the surface of rotating roll in exploitation conditions. Based on the research results, the criteria equations were given which characterize heat transfer in the dynamic conditions of dryer roll rotation. Relatively simple construction and low specific energy consumption make these dryers very attractive for application in chemical, food and textile industry.

Tolmac, D.; Lambic, M. [Univ. in Novi Sad, Zrenjanin (Yugoslavia). Technical Faculty Mihajlo Pupin

1997-07-01

 
 
 
 
341

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

342

Hydrogen effect on cold rolling texture of stable ?-titanium alloy  

International Nuclear Information System (INIS)

A study was made into microstructure and texture of cold rolled titanium alloy VT-35 with various hydrogen content aimed to reveal hydrogen influence on the mechanism of cold plastic deformation by rolling. Experiments were carried out using sheets 1.2 mm thick hydrogenated up to hydrogen concentrations from 0.06 to 0.554 mass. %. All specimens constituted a single-phase FCC ?-solid solution. It is shown that small hydrogen additions have a plasticizing effect on ?-titanium alloys in their cold rolling. The character of texture is dependent on hydrogen concentration and determined by deformation mechanism. 6 refs.; 5 figs

1996-10-01

343

Effect of biomimetic coupling units' morphologies on rolling contact fatigue wear resistance of steel from machine tool rolling tracks  

Science.gov (United States)

The rolling contact fatigue wear resistance plays an important role on ensuring machining precision of machine tool using rolling tracks. Bio-inspired wearable surfaces with the alternated hardness were prepared on the specimen of steel material from machine tool rolling tracks by biomimetic coupling laser remelting method to imitate biological coupling principle. The microstructures and micromorphologies of bionic units in different sizes were characterized by optical microscope. The specimens with bionic units in different sizes and distributions were tested for rolling contact fatigue wear resistance. Combining the finite element analysis and the results of wear tests, a discussion on rolling contact fatigue wear was had. The specimens with bionic units had better rolling contact fatigue wear resistance than the untreated one, while the specimens with bionic units in the alternative depth's distributions present a better rolling contact fatigue wear resistance than the ones with bionic units in the single depth's distribution. It attributed to the alternative distribution made further improvement on the dispersion of depth of stress concentration.

Yang, Wanshi; Zhou, Hong; Sun, Liang; Wang, Chuanwei; Chen, Zhikai

2014-04-01

344

Application of powder metallurgy and hot rolling processes for manufacturing aluminum/alumina composite strips  

Energy Technology Data Exchange (ETDEWEB)

In this study, aluminum matrix composites (AMC) with 2, 4, 6 and 10 wt% alumina were produced using powder metallurgy (PM), mechanical milling (MM) and vacuum hot pressing (VHP) techniques; then, this was followed by the hot-rolling process. During hot rolling, AMCs with 6 and 10 wt% Al{sub 2}O{sub 3} were fractured whereas strip composites with 2 and 4 wt% Al{sub 2}O{sub 3} were produced successfully. Microstructure and mechanical properties of the samples were investigated by optical and scanning electron microscopes and tensile and hardness tests, respectively. Microscopic evaluations of the hot-rolled composites showed a uniform distribution of alumina particles in the aluminum matrix. It was found that with increasing alumina content in the matrix, tensile strength (TS) and hardness increased and the percentage of elongation also decreased. Scanning electron microscope (SEM) was used to investigate aluminum/alumina interfaces and fracture surfaces of the hot rolled specimens after tensile test. SEM observations demonstrated that the failure mode in the hot-rolled Al-2 wt% Al{sub 2}O{sub 3} composite strips is a typical ductile fracture, while the failure mode was shear ductile fracture with more flat surfaces in Al-4 wt% Al{sub 2}O{sub 3} strips.

Zabihi, Majed, E-mail: m.zabihi@ma.iut.ac.ir [Department of Materials Engineering, Isfahan University of Technology, Isfahan 84156-83111 (Iran, Islamic Republic of); Toroghinejad, Mohammad Reza, E-mail: toroghi@cc.iut.ac.ir [Department of Materials Engineering, Isfahan University of Technology, Isfahan 84156-83111 (Iran, Islamic Republic of); Shafyei, Ali, E-mail: shafyei@cc.iut.ac.ir [Department of Materials Engineering, Isfahan University of Technology, Isfahan 84156-83111 (Iran, Islamic Republic of)

2013-01-10

345

Application of powder metallurgy and hot rolling processes for manufacturing aluminum/alumina composite strips  

International Nuclear Information System (INIS)

In this study, aluminum matrix composites (AMC) with 2, 4, 6 and 10 wt% alumina were produced using powder metallurgy (PM), mechanical milling (MM) and vacuum hot pressing (VHP) techniques; then, this was followed by the hot-rolling process. During hot rolling, AMCs with 6 and 10 wt% Al2O3 were fractured whereas strip composites with 2 and 4 wt% Al2O3 were produced successfully. Microstructure and mechanical properties of the samples were investigated by optical and scanning electron microscopes and tensile and hardness tests, respectively. Microscopic evaluations of the hot-rolled composites showed a uniform distribution of alumina particles in the aluminum matrix. It was found that with increasing alumina content in the matrix, tensile strength (TS) and hardness increased and the percentage of elongation also decreased. Scanning electron microscope (SEM) was used to investigate aluminum/alumina interfaces and fracture surfaces of the hot rolled specimens after tensile test. SEM observations demonstrated that the failure mode in the hot-rolled Al-2 wt% Al2O3 composite strips is a typical ductile fracture, while the failure mode was shear ductile fracture with more flat surfaces in Al-4 wt% Al2O3 strips.

2013-01-10

346

Nondestructive evaluation of martensite content in the microstructure of rolled steel wire  

International Nuclear Information System (INIS)

In the microstructure of carbon steel wires, produced on wire rolling mills with controlled cooling, martensite in a certain amount can be formed. Martensite lowers the ductility of the material. An electromagnetic method for nondestructive evaluation of this martensite content had been developed for an in mill quality check. With this method the influence of microstructural stresses on relative permeability is measured. Under in mill conditions, a rejection level for the martensite content of 1.5% abs. can be granted. The use of this new method saves about 60% of the expenses for metallographic examinations. (orig.)

1984-07-01

347

Nondestructive evaluation of martensite content in the microstructure of rolled steel wire  

Energy Technology Data Exchange (ETDEWEB)

In the microstructure of carbon steel wires, produced on wire rolling mills with controlled cooling, martensite in a certain amount can be formed. Martensite lowers the ductility of the material. An electromagnetic method for nondestructive evaluation of this martensite content had been developed for an in mill quality check. With this method the influence of microstructural stresses on relative permeability is measured. Under in mill conditions, a rejection level for the martensite content of 1.5% abs. can be granted. The use of this new method saves about 60% of the expenses for metallographic examinations.

Polanschuetz, W.

1984-07-01

348

Flows in forward deformable roll coating gaps: Comparison between spring and plane-strain models of roll cover  

International Nuclear Information System (INIS)

In this report the flow between rigid and a deformable rotating rolls fully submerged in a liquid pool is studied. The deformation of compliant roll cover is described by two different models (1) independent, radially oriented springs that deform in response to the traction force applied at the extremity of each or one-dimensional model, and (2) a plane-strain deformation of an incompressible Mooney-Rivlin material or non-linear elastic model. Based on the flow rate predictions of both models, an empirical relation between the spring constant of the one dimensional model and the roll cover thickness and elastic modulus is proposed

1997-12-01

349

21 CFR 136.180 - Whole wheat bread, rolls, and buns.  

Science.gov (United States)

...false Whole wheat bread, rolls, and buns. 136.180 Section 136.180 Food...180 Whole wheat bread, rolls, and buns. (a) Each of the foods whole wheat...rolls, entire wheat rolls, whole wheat buns, graham buns, and entire wheat...

2009-04-01

350

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 structureâ??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

351

Thermobimetals Mechanical Properties Produced by Explosive Welding with Rolling  

Digital Repository Infrastructure Vision for European Research (DRIVER)

We used explosive welding with rolling to produce thermobimetals on the basis of beryllium bronze and alloys of nickel. It gave us possibility to obtain magnetic and non-magnetic thermobimetals possessing high physical and mechanical properties.

Gulbin, V.; Kobelev, A.; Borissov, D.

1997-01-01

352

Properties of doped boiler steel after controlled rolling  

Energy Technology Data Exchange (ETDEWEB)

The article shows that the structural strength of carbon boiler steel type 20K can be enhanced by doping with vanadium or niobium and by controlled rolling and controlled cooling. 8 refs., 6 figs., 1 tab.

Bobylev, M.V.; Kireev, V.B.; Koreshkova, A.M.

1992-03-01

353

The Rolling Motion of a Disk on a Horizontal Plane  

CERN Multimedia

This classic problem is reviewed with the goal of identifying frictional forces that cause the system to evolve. A debate as to the type of friction that halts the rolling motion should be settled experimentally.

McDonald, K T

2000-01-01

354

Competition between roll and square convection patterns in binary mixtures  

International Nuclear Information System (INIS)

We present a few-mode Galerkin model for convection in binary fluid layers subject to impermeable horizontal boundary conditions at positive separation ratios. It describes convection in the form of rolls in x direction, y direction, and squares. To incorporate symmetry-breaking sidewall forces selecting the spatial phase of the patterns relative to the walls we introduce into the model equations a single small inhomogeneity that favors the experimentally realized phase. Then squares are stabilized shortly above onset of convection where the amplitudes are very small. Far above onset, the amplitudes strongly increase, nonlinear mode coupling dominates, and causes rolls to be stable. In an intermediate regime, there are oscillations between the three competing patterns of rolls in x direction, squares, and rolls in y direction. Heat transport, spatial, and temporal behavior of the various convective states are in good agreement with recent experiments

1988-09-15

355

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

356

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

357

Parallel Estimation Respecting Constraints of Parametric Models of Cold Rolling.  

Czech Academy of Sciences Publication Activity Database

steel industryKód oboru RIV: BB - Aplikovaná statistika, opera?ní výzkum http://library.utia.cas.cz/separaty/2010/AS/karny-parallel estimation respecting constraints of parametric models of cold rolling.pdf

Ettler, P.; Kárný, Miroslav

358

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%.

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

2010-05-01

359

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

360

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

 
 
 
 
361

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 the visual spectrum (lambdamax approximately 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. PMID:17251115

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

2007-03-22

362

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 the 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.

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

2007-01-01

363

Mesomorphic Lamella Rolling of Au in Vacuum  

Directory of Open Access Journals (Sweden)

Full Text Available Abstract Lamellar nanocondensates in partial epitaxy with larger-sized multiply twinned particles (MTPs or alternatively in the form of multiple-walled tubes (MWTs having nothing to do with MTP were produced by the very energetic pulse laser ablation of Au target in vacuum under specified power density and pulses. Transmission electron microscopic observations revealed (111-motif diffraction and low-angle scattering. They correspond to layer interspacing (0.241–0.192 nm and the nearest neighbor distance (ca. 0.74–0.55 nm of atom clusters within the layer, respectively, for the lamella, which shows interspacing contraction with decreasing particle size under the influence of surface stress and rolls up upon electron irradiation. The uncapped MWT has nearly concentric amorphous layers interspaced by 0.458–0.335 nm depending on dislocation distribution and becomes spherical onions for surface-area reduction upon electron dosage. Analogous to graphene-derived tubular materials, the lamella-derived MWT of Au could have pentagon–hexagon pair at its zig-zag junction and useful optoelectronic properties worthy of exploration.

Chen Shuei-Yuan

2009-01-01

364

Mesomorphic Lamella Rolling of Au in Vacuum  

Science.gov (United States)

Lamellar nanocondensates in partial epitaxy with larger-sized multiply twinned particles (MTPs) or alternatively in the form of multiple-walled tubes (MWTs) having nothing to do with MTP were produced by the very energetic pulse laser ablation of Au target in vacuum under specified power density and pulses. Transmission electron microscopic observations revealed (111)-motif diffraction and low-angle scattering. They correspond to layer interspacing (0.241-0.192 nm) and the nearest neighbor distance (ca. 0.74-0.55 nm) of atom clusters within the layer, respectively, for the lamella, which shows interspacing contraction with decreasing particle size under the influence of surface stress and rolls up upon electron irradiation. The uncapped MWT has nearly concentric amorphous layers interspaced by 0.458-0.335 nm depending on dislocation distribution and becomes spherical onions for surface-area reduction upon electron dosage. Analogous to graphene-derived tubular materials, the lamella-derived MWT of Au could have pentagon-hexagon pair at its zig-zag junction and useful optoelectronic properties worthy of exploration.

Huang, Chang-Ning; Chen, Shuei-Yuan; Shen, Pouyan

2009-11-01

365

SOFC technology development at Rolls-Royce  

Science.gov (United States)

Fuel cells have the prospect for exploiting fossil fuels more benignly and more efficiently than alternatives. The various types represent quite different technologies, with no clear winner, yet. Nevertheless, the high temperature MCFC and solid oxide fuel cell (SOFC) types seem better suited to power generation in a hydrocarbon fuel economy. Presently, the costs of MCFCs and SOFCs are too high to compete directly with contemporary power generation plant. Seeking to overcome the drawbacks of first generation fuel cells, over the past 7 years an innovative second generation SOFC concept has been evolved in the Rolls-Royce Strategic Research Centre, with encouraging results. It is distinguished from other types by the name: Integrated Planar Solid Oxide Fuel Cell (IP-SOFC). It is a family of integrated system concepts supporting product flexibility with evolutionary stretch potential from a common SOFC module. Fabrication of the key component of the IP-SOFC, the "multi-cell membrane electrode assembly (multi-cell MEA) module" carrying many series connected cells with supported electrolyte membranes only 10 to 20 ?m thick, has been proved. Development of the internal reforming subsystem, the next big hurdle, is now in hand. Following an outline of its salient features and test results, the methodology and results of recent IP-SOFC stack costing studies are presented, and the continuing research and development programme indicated.

Gardner, F. J.; Day, M. J.; Brandon, N. P.; Pashley, M. N.; Cassidy, M.

366

STS-103 Discovery rolls over to VAB  

Science.gov (United States)

The orbiter Discovery rolls along the tow-way to the Vehicle Assembly Building where it will be mated with an external tank and solid rocket boosters for its launch on mission STS-103. The launch date is currently under review for early December. STS-103, the third Hubble Space Telescope servicing mission, is a 'call-up' due to the need to replace portions of the pointing system, the gyros, which have begun to fail on the Hubble Space Telescope. Although Hubble is operating normally and conducting its scientific observations, only three of its six gyroscopes are working properly. The gyroscopes allow the telescope to point at stars, galaxies and planets. The STS-103 crew will also be replacing a Fine Guidance Sensor and an older computer with a new enhanced model, an older data tape recorder with a solid-state digital recorder, a failed spare transmitter with a new one, and degraded insulation on the telescope with new thermal insulation. The crew will also install a Battery Voltage/Temperature Improvement Kit to protect the spacecraft batteries from overcharging and overheating when the telescope goes into a safe mode.

1999-01-01

367

Effect of Rolling Massage on Particle Moving Behaviour in Blood Vessels  

International Nuclear Information System (INIS)

The rolling massage manipulation is a classic Chinese massage, which is expected to eliminate many diseases. Here the effect of the rolling massage on the particle moving property in the blood vessels under the rolling massage manipulation is studied by the lattice Boltzmann simulation. The simulation results show that the particle moving behaviour depends on the rolling velocity, the distance between particle position and rolling position. The average values, including particle translational velocity and angular velocity, increase as the rolling velocity increases almost linearly. The result is helpful to understand the mechanism of the massage and develop the rolling techniques. (cross-disciplinary physics and related areas of science and technology)

2008-09-01

368

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

369

Rolling contact fatigue testing of peek based composites  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Rolling contact fatigue phenomenon was investigated on unfilled PEEK and on three different PEEK composites: 10% carbon micro-fiber, graphite and PTFE filled matrix, 30% carbon micro-fiber filled matrix, 30% glass micro-fiber filled matrix. For this aim, roller-shaped specimens were machined from extruded bars of these materials and subjected to rolling contact tests at different contact pressure levels by means of a four roller machine. Contact pressure-life diagrams and wear rates wer...

Avanzini A.; Donzella G.; Gallina D.; Pandini S.; Petrogalli C.

2010-01-01

370

Model based development of a roll angle estimator for motorcycles.  

Digital Repository Infrastructure Vision for European Research (DRIVER)

This report compares the development tools Ascet and Matlab with regard to their suitability as tools for model based development of signal processing software for embedded systems. We derive appropriate metrics of quality and perform an implementation of a signal processing algorithm called RAI, Roll Angle Indicator, in both tools. RAI is an algorithm that with an Extended Kalman Filter estimates the roll angle, that is how much a motorcycle is leaning. From the models implemented in Ascet a...

Eriksson, Sofia; Isaksson, Petter

2003-01-01

371

Studying cell rolling trajectories on asymmetric receptor patterns  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Lateral displacement of cells orthogonal to a flow stream by rolling on asymmetric receptor patterns presents an opportunity for development of new devices for label-free separation and analysis of cells[1]. Such devices may use lateral displacement for continuous-flow separation, or receptor patterns that modulate adhesion to distinguish between different cell phenotypes or levels of receptor expression. Understanding the nature of cell rolling trajectories on receptor-patterned substrates i...

Lee, Chia-hua; Bose, Suman; Vliet, Krystyn J.; Karp, Jeffrey Michael; Karnik, Rohit

2011-01-01

372

Slow-roll inflation without fine-tuning  

CERN Document Server

The slow-roll approximation is the usual starting point to study the constraints imposed on the inflaton potential parameters by the observational data. We show that, for a potential exhibiting at least two extrema and giving rise to a limited inflationary period, slow-roll does not have to be taken as an additional hypothesis and is in fact forced by the constraints on the number of e-foldings.

Charters, T C; Nunes, A; Charters, Tiago; Mimoso, Jose P.; Nunes, Ana

2000-01-01

373

Nature of Roll to Spiral-Defect-Chaos Transition  

Digital Repository Infrastructure Vision for European Research (DRIVER)

We investigate the nature of the parallel-roll to spiral-defect-chaos (SDC) transition in Rayleigh-Benard convection, based on the generalized Swift-Hohenberg model. We carry out extensive, systematic numerical studies by, on one branch, increasing the control parameter gradually from the parallel roll regime to the SDC regime and, on the other branch, decreasing it in the opposite manner. We find that the data of several time-averaged global quantities all form hysteretic l...

Li, Xiao-jun; Xi, Hao-wen; Gunton, J. D.

1997-01-01

374

Impact of mechanical anisotropy on flat-rolled wires geometry  

Digital Repository Infrastructure Vision for European Research (DRIVER)

A precise final geometry of flat-rolled wires is required in view of their industrial applications. However, comparison between experimental and computed cross-sections shows a gap of 10%. This difference might originate in the anisotropy introduced by wire drawing. Coefficients of an anisotropic constitutive model (Hill 48) have been identified from transverse compression tests. Then Lam3®, a finite element software, has been used to simulate rolling passes. The anisotropic law previously e...

Masse?, Thomas; Chastel, Yvan; Fourment, Lionel; Montmitonnet, Pierre; Bobadilla, Christian; Persem, Nicolas; Foissey, Sylvain

2009-01-01

375

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

376

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

377

Sticking Phenomenon Occurring during Hot Rolling of Ferritic Stainless Steels  

International Nuclear Information System (INIS)

Sticking phenomenon occurring during hot rolling of two ferritic stainless steels, STS 430J1L and STS 436L, was investigated in this study. A hot rolling simulation test was carried out using a high-temperature wear tester capable of controlling rolling speed, load, and temperature. The simulation test results at 900 .deg. C and 1000 .deg. C revealed that the sticking process proceeded with three stages, i.e., nucleation, growth, and saturation, for the both stainless steels, and that STS 430J1L had a smaller number of sticking nucleation sites than the STS436L because of higher high-temperature hardness, thereby leading to a smaller amount of the sticking. When the test temperature was 1070 .deg. C, the sticking hardly occurred in both stainless steels as Fe-Cr oxide layers were formed on the surface of the rolled materials. These findings suggested that the improvement of high-temperature properties of stainless steels and the appropriate rolling conditions for readily forming oxide layers on the rolled material surface were required in order to prevent or minimize the sticking

2007-01-01

378

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)

1991-01-01

379

Toroidal convection rolls in the sun a challenge to theory  

Science.gov (United States)

A large-scale circulation in the form of azimuthal (east-west oriented) rolls has been discovered in the convection zone of the Sun (Ribes et al.0, 1985; Ribes, 1986). The characteristics of the global circulation (for example orientation, number, lifetime and so forth) are quite different from those of meridional cells (oriented parallel to the solar axis) which has been predicted by theory (e.g. Glatzmaier, 1985). This raises the important question as to whether or not the newly-discovered azimuthal rolls contribute to the transport of heat from the deep interior of the Sun to its surface. Here we report new results that exhibit the convective nature of the azimuthal rolls. These are based on 22 years of observation of the roll pattern (Ribes, 1986), a 11 year sequence of solar diameter measurements (Laclare, 1987), and four years of luminosity measurements (Willson et al., 1981). The first indication is provided by the distribution of solar activity, which frames the roll pattern rather than being superimposed on it. The second hint comes from a temporal association that exists between the onset of new rolls and the luminosity and diameter oscillations with a period of 980 days.

Ribes, E.; Laclare, F.

380

Annealing behavior of cold-rolled reactor pressure vessel steel  

Energy Technology Data Exchange (ETDEWEB)

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.

Lee, Geol Woo

1993-02-15

 
 
 
 
381

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

382

Flexible IZO/Ag/IZO/Ag multilayer electrode grown on a polyethylene terephthalate substrate using roll-to-roll sputtering  

Digital Repository Infrastructure Vision for European Research (DRIVER)

We investigated the optical, electrical, structural, and surface properties of roll-to-roll [R2R] sputter-grown flexible IZO/Ag/IZO/Ag [IAIA] multilayer films on polyethylene terephthalate substrates as a function of the top indium zinc oxide [IZO] thickness. It was found that the optical transmittance of the IAIA multilayer was significantly influenced by the top IZO layer thickness, which was grown on identical AIA multilayers. However, the sheet resistance of the IAIA multilayer was mainta...

Kim, Han-ki; Lim, Jong-wook

2012-01-01

383

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

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...

Woon, H. S.; Lim, K. P.; Puteri, N.; Rozaimah, R.; Tan, C. Y.

2009-01-01

384

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 rolling-volume journals suggests that LIS journal editors are making forward-looking choices about publication models even though the topic has not been much addressed in the library literature. Further research is warranted; possibilities include expanding the study’s geographic scope, broadening the study to other disciplines, and investigating publication model trends across the entire scholarly OA universe. CONCLUSION Both because satisfaction is high among editors of rolling-volume journals and because readers and authors appreciate quick publication times, the rolling-volume model will likely become even more prevalent in coming years.

Jill Cirasella

2013-08-01

385

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

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: Portuguese Abstract in portuguese 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). T [...] odos 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 utilizado para gerar uma curva de cubagem para a espécie. Abstract in english This study was carried out with the aim of generating a taper equation for Virola surinamensis (Roll.) Warb, which is among the main exported species by the wood industries from the Amazonian estuary. The Kozak (1969), Baldwin (1991), Demaerschalk (1972) and Garay (1979) mathematical models were tes [...] ted. All the tested models estimated the diameter with good precision, however, the first three models resulted in inconsistency while estimating commercial height. The Garay model was chosen and used to generate a cubage curve for the species.

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

386

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

Directory of Open Access Journals (Sweden)

Full Text Available 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 utilizado para gerar uma curva de cubagem para a espécie.This study was carried out with the aim of generating a taper equation for Virola surinamensis (Roll. Warb, which is among the main exported species by the wood industries from the Amazonian estuary. The Kozak (1969, Baldwin (1991, Demaerschalk (1972 and Garay (1979 mathematical models were tested. All the tested models estimated the diameter with good precision, however, the first three models resulted in inconsistency while estimating commercial height. The Garay model was chosen and used to generate a cubage curve for the species.

Helio Garcia Leite

2006-02-01

387

Roll-to-roll embedded conductive structures integrated into organic photovoltaic devices.  

Science.gov (United States)

Highly conductive screen printed metallic (silver) structures (current collecting grids) combined with poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate) (PEDOT:PSS) are a viable replacement for indium tin oxide (ITO) and inkjet printed silver as transparent electrode materials. To provide successful integration into organic photovoltaic (OPV) devices, screen printed silver current collecting grids should be embedded into a substrate to avoid topology issues. In this study micron-thick conductive structures are embedded and integrated into OPV devices. The embedded structures are produced roll-to-roll with optimized process settings and materials. Topology measurements show that the embedded grids are well suited for integration into OPV devices since the surface is almost without spikes and has low surface roughness. JV measurements of OPV devices with embedded structures on a polyethylene terephthalate/silicon nitride (PET/SiN) substrate show an efficiency of 2.15%, which is significantly higher than identical flexible devices with ITO (1.02%) and inkjet printed silver (1.48%). The use of embedded screen printed silver instead of ITO and inkjet printed silver in OPV devices will allow for higher efficiency devices which can be produced with larger design and process freedom. PMID:24196842

van de Wiel, H J; Galagan, Y; van Lammeren, T J; de Riet, J F J; Gilot, J; Nagelkerke, M G M; Lelieveld, R H C A T; Shanmugam, S; Pagudala, A; Hui, D; Groen, W A

2013-12-01

388

Roll-to-Roll Screen Printed Radio Frequency Identification Transponder Antennas for Vehicle Tracking Systems  

Science.gov (United States)

Vehicle tracking systems based on ultra high frequency (UHF) radio frequency identification (RFID) technology are already introduced to control the access to car parks and corporate premises. For this field of application so-called Windshield RFID transponder labels are used, which are applied to the inside of the windshield. State of the art for manufacturing these transponder antennas is the traditional lithography/etching approach. Furthermore the performance of these transponders is limited to a reading distance of approximately 5 m which results in car speed limit of 5 km/h for identification. However, to achieve improved performance compared to existing all-purpose transponders and a dramatic cost reduction, an optimized antenna design is needed which takes into account the special dielectric and in particular metallic car environment of the tag and an roll-to-roll (R2R) printing manufacturing process. In this paper we focus on the development of a customized UHF RFID transponder antenna design, which is adopted for vehicle geometry as well as R2R screen printing manufacturing processes.

Zichner, Ralf; Baumann, Reinhard R.

2013-05-01

389

Patterned immobilization of antibodies within roll-to-roll hot embossed polymeric microfluidic channels.  

Science.gov (United States)

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 was followed by a second deposition of antibody by overprinting on the PEI-GA patterned PMMA foil. The PEI polymer ink was first formulated to ensure stable drop formation in inkjet printing and the printed films were characterized using atomic force microscopy (AFM) and X-ray photoelectron spectroscopy (XPS). Anti-CRP antibody was patterned on PMMA foil by the developed method and bonded permanently with R2R hot embossed PMMA microchannels by solvent bonding lamination. The functionality of the immobilized antibody inside the microfluidic channel was evaluated by fluorescence-based sandwich immunoassay for detection of C-reactive protein (CRP). The antibody-antigen assay exhibited a good level of linearity over the range of 10 ng/ml to 500 ng/ml (R(2)?=?0.991) with a calculated detection limit of 5.2 ng/ml. The developed patterning method is straightforward, rapid and provides a versatile approach for creating multiple protein patterns in a single microfluidic channel for multiplexed immunoassays. PMID:23874811

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

2013-01-01

390

Multivariable passive RFID vapor sensors: roll-to-roll fabrication on a flexible substrate.  

Science.gov (United States)

We demonstrate roll-to-roll (R2R) fabrication of highly selective, battery-free radio frequency identification (RFID) sensors on a flexible polyethylene terephthalate (PET) polymeric substrate. Selectivity of our developed RFID sensors is provided by measurements of their resonance impedance spectra, followed by the multivariate analysis of spectral features, and correlation of these spectral features to the concentrations of vapors of interest. The multivariate analysis of spectral features also provides the ability for the rejection of ambient interferences. As a demonstration of our R2R fabrication process, we employed polyetherurethane (PEUT) as a "classic" sensing material, extruded this sensing material as 25, 75, and 125-?m thick films, and thermally laminated the films onto RFID inlays, rapidly producing approximately 5000 vapor sensors. We further tested these RFID vapor sensors for their response selectivity toward several model vapors such as toluene, acetone, and ethanol as well as water vapor as an abundant interferent. Our RFID sensing concept features 16-bit resolution provided by the sensor reader, granting a highly desired independence from costly proprietary RFID memory chips with a low-resolution analog input. Future steps are being planned for field-testing of these sensors in numerous conditions. PMID:22358260

Potyrailo, Radislav A; Burns, Andrew; Surman, Cheryl; Lee, D J; McGinniss, Edward

2012-06-21

391

Roll-to-Roll Solution-Processible Small-Molecule OLEDs  

Energy Technology Data Exchange (ETDEWEB)

The objective of this program is to develop key knowledge and make critical connections between technologies needed to enable low-cost manufacturing of OLED lighting products. In particular, the program was intended to demonstrate the feasibility of making high performance Small-Molecule OLEDs (SM-OLED) using a roll-to-roll (R2R) wet-coating technique by addressing the following technical risks (1) Whether the wet-coating technique can provide high performance OLEDs, (2) Whether SM-OLED can be made in a R2R manner, (3) What are the requirements for coating equipment, and (4) Whether R2R OLEDs can have the same performance as the lab controls. The program has been managed and executed according to the Program Management Plan (PMP) that was first developed at the beginning of the program and further revised accordingly as the program progressed. Significant progress and risk reductions have been accomplished by the end of the program. Specific achievements include: (1) Demonstrated that wet-coating can provide OLEDs with high LPW and long lifetime; (2) Demonstrated R2R OLEDs can be as efficient as batch controls (Figure 1) (3) Developed & validated basic designs for key equipment necessary for R2R SM-OLEDs; (4) Developed know-hows & specifications on materials & ink formulations critical to wetcoating; (5) Developed key R2R processes for each OLED layer (6) Identified key materials and components such as flexible barrier substrates necessary for R2R OLEDs.

Liu, Jie Jerry

2012-07-31

392

Adaptation of roll-to-roll imprint lithography: from flexible electronics to structural templates  

Science.gov (United States)

HP has previously demonstrated the roll-to-roll (R2R) fabrication of active-matrix display backplanes using the Self-Aligned Imprint Lithography (SAIL) process. This approach permits a single imprint step to create a multi level mask comprising all patterns required for subsequent etching steps, obviating the need for multiple alignment steps. In this paper the imprint lithography technique and aspects of SAIL are reviewed. New work using imprint processing to generate structural templates, with aspect ratios approaching 6:1, for fluid containment will be presented. Arrays of transparent well structures, formed on a flexible transparent substrate provide the basis for a color display filter matrix that is filled by inkjet deposition of pigmented resins. A primary benefit of this approach is precise color pattern definition. A separation between primary color fields of 4 microns is realized without risk of color mixing or overlap. Components patterned with high absolute precision by imprint lithography were readily integrated with parts from other sources to yield flexible color reflective display demonstrator panels. This work highlights the flexibility of imprint processing and its suitability for use with a wide variety of materials and in differing applications.

Holland, Edward R.; Jeans, Albert; Mei, Ping; Taussig, Carl P.; Elder, Richard E.; Bell, Cynthia; Howard, Emmett; Stowell, John

2011-03-01

393

Design of an airframe agnostic roll-on/roll-off (AA-RORO) sensor platform  

Science.gov (United States)

The US military has recently taken tactical steps to increase its ISR capabilities to support military operations. Due to the dynamic capabilities of the terrorist threat, there is a need for a payload- and airframe-agnostic, rapid-deployment sensor system that can be used on multiple airframes for in-theater missions and for the test and evaluation of sensors prior to fielding. This "plug-and-play" system, based upon the Oculus Sensor Deployment System technology, uses a system-of-systems approach to modularize the base platform, thereby allowing the system to conform to aircraft such as the C-130, C-27, V-22, CH-47, CH-53 and CASA-235 without any modification to the airframe itself. This type of system can be used as (1) a versatile, cost-effective test and evaluation platform for current and developmental sensors as well as (2) an in-theater ISR asset that can be used on readily available airframes at a particular location. This paper illustrates the CONUS and OCONUS mission potential of this multi-airframe system and outlines the novel design characteristics that the Airframe Agnostic Roll-on/Roll-off (AA-RORO) sensor platform incorporates to make it the most versatile, rapid-deployment sensor platform available to support near-term U.S. military operations. The system concept was developed with the support of and input from multiple military agencies and the respective branches they represent.

Sparks, Bruce; Wowczuk, Zenovy S.; Harrison, A. Jay

2009-05-01

394

Ellipsometry as a Nondestructive Depth Profiling Tool for Roll-to-Roll Manufactured Flexible Solar Cells  

DEFF Research Database (Denmark)

We show that it is possible to perform ellipsometry on large area roll-to-roll (R2R) coated solar cells on flexible substrates and further demonstrate that the slot-die coating technique employed yields the same bulk heterojunction (BHJ) film morphology and vertical phase separation as laboratory samples prepared by the spin coating technique. The solar cell device geometry was Kapton/Al/Cr/P3HT:PCBM/PEDOT:PSS/Ag. Variable angle ellipsometry was used to determine the optical dispersions of the pure phases of P3HT and PCBM allowing an effective medium approximation model to be employed. It was found that a top layer phase separation of P3HT and a vertical linear gradient of P3HT and PCBM best described the BHJ layer. The model was tested for samples of varying thickness and blend composition, model parameters including thickness (AFM), vertical composition (XPS depth profiling), and optical transmission (optical simulation and UVâ??visible spectroscopy comparisons) was confirmed to comply with the model. A meansof quality testing and optimization of the coating procedure line scans across a R2R slot-die-coated sample over large distances (8 cm) was made giving insight into thickness and composition uniformity.

Vesterager Madsen, Morten; Sylvester-Hvid, Kristian O.

2011-01-01

395

Roll-to-Roll Inkjet Printing and Photonic Sintering of Electrodes for ITO Free Polymer Solar Cell Modules and Facile Product Integration  

DEFF Research Database (Denmark)

Small polymer solar cell modules that are manufactured without indium-tin-oxide using only roll-to-roll printing and coating techniques under ambient conditions enable facile integration into a simple demonstrator (for example a laser pointer). Semitransparent front electrode grid structures prepared by roll-to-roll inkjet printing in conjunction with photonic sintering enabled preparation of complete modules on flexible substrates and subsequent integration of the modules into a laser pointer demonstrator.

Angmo, Dechan; Larsen-Olsen, Thue Trofod

2013-01-01

396

Modeling precipitation and its effect on recrystallization during hot strip rolling of niobium steels  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Using a physically based model, the microstructural evolution of Nb microalloyed steels during rolling in SSAB Tunnplåt’s hot strip mill was modeled. The model describes the evolution of dislocation density, the creation and diffusion of vacancies, dynamic and static recovery through climb and glide, subgrain formation and growth, dynamic and static recrystallization and grain growth. Also, the model describes the dissolution and precipitation of particles. The impeding effect on g...

Lissel, Linda; Engberg, Go?ran; Borggren, Ulrika

2008-01-01

397

Dimethylsulfoxide exposure modulates HL-60 cell rolling interactions  

Directory of Open Access Journals (Sweden)

Full Text Available Human leukaemic HL-60 cells are widely used for studying interactions involving adhesion molecules [e.g. P-selectin and PSGL-1 (P-selectin glycoprotein ligand-1] since their rolling behaviour has been shown to mimic the dynamics of leucocyte rolling in vitro. HL-60 cells are neutrophilic promyelocytes that can undergo granulocytic differentiation upon exposure to compounds such as DMSO (dimethylsulfoxide. Using a parallel plate flow chamber functionalized with recombinant P-selectin–Fc chimaera, undifferentiated and DMSO-induced (48, 72 and 96 h HL-60 cells were assayed for rolling behaviour. We found that depending on P-selectin incubation concentration, undifferentiated cells incurred up to a 6-fold increase in rolling velocity while subjected to an approximately 10-fold increase in biologically relevant shear stress. HL-60 cells exposed to DMSO for up to 72 h incurred up to a 3-fold increase in rolling velocity over the same shear stress range. Significantly, cells exposed for up to 96 h incurred up to a 9-fold decrease in rolling velocity, compared with undifferentiated HL-60 cells. Although cell surface and nuclear morphological changes were evident upon exposure to DMSO, flow cytometric analysis revealed that PSGL-1 expression was unchanged, irrespective of treatment duration. The results suggest that DMSO-treated HL-60 cells may be problematic as a substitute for neutrophils for trafficking studies during advanced stages of the LAC (leucocyte adhesion cascade. We suggest that remodelling of the cell surface during differentiation may affect rolling behaviour and that DMSO-treated HL-60 cells would behave differently from the normal leucocytes during inflammatory response in vivo.

David J. Gee

2012-05-01

398

High speed twin roll casting of 6061 alloy strips  

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 strips of two aluminum alloys:6061 and recycled 6061. Mechanical properties of the roll cast 6061 and recycled 6061 strips were investigated inthe frame of this purpose.Design/methodology/approach: Methods used in the present study were high speed twin roll caster and lowtemperature casting. These methods were used to realize rapid solidification and increase the casting speed.Findings: are that 6061 and recycled 6061 could be cast at speed of 60 m/min. Casted strips were about 3 mmthick. As cast strip could be cold-rolled down to sheet of 1 mm thick. 180 degrees bending test was operated on thesheet after T4 heat treatment and crack was not worse than 6022 which is typical aluminum alloy for sheet of theautomobile. This result means the roll cast 6061 can be used as a sheet for body of the automobile instead of 6022.Research limitations/implications: Research limitation is that the width of the strip was 100 mm andinvestigation of the properties were enough for practical use. Wider strip must be cast using the twin roll caster ofthe size for production.Originality/value: The economy sheet of the 6061 for the auto mobile can be produced by the high speed twinroll caster. 6061 is typical wrought aluminum alloy of 6000 series. Therefore, the sheet of 6061 will becomeeconomy. 6061 can be recycled at two times when the 6061 is cast into strip by the high speed roll casting.

T. Haga

2008-05-01

399

Rolling bearing life models and steel internal cleanliness  

Energy Technology Data Exchange (ETDEWEB)

The most widely used steel grade for rolling bearings is based on a steel composition first used almost a hundred years ago, the so-called 1C-1.5Cr steel. This steel is used either in a selective surface induction hardened conditions or in a through hardened heat treated condition, both yielding exceptional structural and contact fatigue properties. The Lundberg and Palmgren rolling bearing life prediction model, published in 1947, was the first analytical approach to bearing performance prediction, subsequently becoming a widely accepted basis for rolling bearing life calculations. At that time the fatigue life of rolling bearings was dominated by the classical sub-surface initiated failure mode. This mode results from the accumulation of micro-plastic strain at the depth of maximum Hertzian stress and is accelerated by the stress concentrations occurring at the micro internal defects. In common with all fatigue processes, rolling bearing failure is a statistical process: the failures of bearings with high inclusion content tested at high stress levels belong to the well-known family of Weibull distributions. Steady improvements in bearing steel cleanliness due, amongst other things, to the introduction of secondary metallurgy steel making techniques, have resulted in a significantly increased rolling bearing life and load carrying capacity. In recognition of this, in 1985 Ioannides and Harris introduced a new fatigue life model for rolling bearings, comprising a more widely applicable approach to the modeling of bearing life based on the relevant failure mode. Subsequently this has been extended to include effects of hardness and of micro-inclusion distributions in state-of-the-art clean bearing steel.

Beswick, J.; Gabelli, A.; Ioannides, S.; Tripp, J.H.; Voskamp, A.P.

1999-07-01

400

Large-scale Roll-to-Roll Fabrication of Organic Solar Cells for Energy Production  

DEFF Research Database (Denmark)

The global energy consumption is increasing steadily while natural energy sources are running out sooner or later. Solar electricity is one of many renewable energy sources that contributes to the worldâ??s demand. Organic solar cells (OPV) are an attractive 3rd generation solar technology that can be produced cheaply and very fast from solution with printing processes. The current research all around the world is still focused on lab-scale sized devices « cm2, ITO-glass substrates, and spin coating as the main fabrication method. These OPV devices are far from any practical application although record efficiencies beyond 10% could be achieved. This dissertation describes process workflows and roll-to-roll (R2R) fabrication methods for upscaling the OPV technology to solar module sizes that enable real power production even at efficiencies 10 kV and power output >220Wpeak could be successfully manufactured while having only two terminal contacts. Real energy production from these modules was studied by setting up a whole solar park based on OPV modules. Infinity modules with a length of 100m (width 0.3 m) were rolled out and taped onto a wooden structure. The maximum power output of six parallel-connected modules with a total active area of 88.2m2 was beyond 1.3 kW while having energy payback times P1 year. Alternative installation concepts such as a balloon or special designed solar tubes on land or water were proved to be functional as well. Solar tubes with Infinity modules of around 200W generated 18 kWh in 5 weeks. The energy was fed back into the Danish power grid. The dissertation contains a brief introduction of organic solar cell technology and reviews important R2R compatible manufacturing methods including photonic sintering. The fabrication, design, and challenges of Flextrode and Infinity modules are described in detail. The potential future energy production is presented through large-scale OPV installation scenarios and performance analyses. Fatal failures such as fully burned cells are described while easy repair mechanisms are shown that avoid costly replacements of full modules. A conclusion and outlook finalizes the dissertation.

Hösel, Markus

2013-01-01

 
 
 
 
401

New progress of FEM simulation and AI application in rolling at RAL  

Energy Technology Data Exchange (ETDEWEB)

New progresses on FEM simulation and AI application in rolling have been achieved at RAL recently. The existence and uniqueness of the extreme point of total functional for rolling problem has been proved. Different rolling processes, such as H-beam rolling, ribbing strip rolling, slab sizing, have been solved by our in-house FEM software package. The simulation results have been put into production use to improve the precision of math models. The Artificial Neural Network has been used to predict rolling force, coiling temperature, microstructure and properties of the rolled products. An expert system for deviation diagnoses of strip thickness has been developed for industry use. Synergetic Artificial Intelligence has also been applied to rolling scheduling. We are making continuous efforts to develop AI applications for rolling line co-operating in China steel industry. (author)

Liu Xianghua; Wang Guodong [Northeastern Univ., State Key Lab. of Rolling and Automation, Shenyang City (China); Zhao Kun [Shanghai Baosteel Yichang Steel Strip Co. Ltd., Shanghai (China)

2000-07-01

402

Lattice Boltzmann simulation of behaviour of particles moving in blood vessels under the rolling massage  

International Nuclear Information System (INIS)

The rolling massage is one of the most important manipulations in Chinese massage, which is expected to eliminate many diseases. Here, the effect of the rolling massage on a pair of particles moving in blood vessels under rolling massage manipulation is studied by the lattice Boltzmann simulation. The simulated results show that the motion of each particle is considerably modified by the rolling massage, and it depends on the relative rolling velocity, the rolling depth, and the distance between particle position and rolling position. Both particles' translational average velocities increase almost linearly as the rolling velocity increases, and obey the same law. The increment of the average relative angular velocity for the leading particle is smaller than that of the trailing one. The result is helpful for understanding the mechanism of the massage and to further develop the rolling techniques. (classical areas of phenomenology)

2009-07-01

403

Wear of steel in rolling contact with silicon nitride  

Energy Technology Data Exchange (ETDEWEB)

Wear of steel (AISI M-50 and AISI 52100) bearing balls in lubricated rolling contact with ground and ground-and-lapped silicon nitride rods was studied using a ball-on-rod rolling-contact-fatigue (RCF) tester. The steel balls suffered significant wear in rolling contact with the as-ground (R{sub a}=0.18 {mu}m) silicon nitride rods. The wear volume loss was approximately linear with the rolling distance. The wear rate increased linearly with the initial Hertzian contact stress in the range, 3-6.5 GPa. Examination of the wear tracks in a scanning electron microscope revealed surface features that suggested a wear mechanism that involved plastic deformation of the steel surface, squeezing of the metal symmetrically outward and rupture of the metal layers at the edges. The steel balls suffered negligible wear but failed by spalling in rolling contact with the ground-and-lapped silicon nitride rods (R{sub a}=0.08 {mu}m) at an initial contact stress of 5.5 GPa. The as-ground silicon nitride rods exhibited neither wear nor spalling in the RCF tests, while the ground-and-lapped silicon nitride rods showed no wear but occasional spalling failure. (orig.)

Lakshminarayanan, R.; Chao, L.Y.; Iyer, N.; Shetty, D.K. [Utah Univ., Salt Lake City, UT (United States)

1997-09-01

404

Finishing of disk tools for rolling spiral fins on tubes  

Energy Technology Data Exchange (ETDEWEB)

At the All-Union Scientific-Research and Design Institute for Chemical and Petroleum Apparatus Building Technology, Volgograd, a special machine has been designed and built and investigations have been made to provide tool working surfaces with high quality. Finds that the increase in surface quality of the rolling tools as a result of abrasive grinding with a belt on the special machine makes it possible to reduce external friction in the rolling zone, as a result of which there is an improvement in the conditions of radial flow of the tube metal. Savings are obtained as a result of a decrease in the power required by the electric motors for rolling of finned tubes. This is an indication of a reduction in the forces of friction in the source of change in form of the fins and approximately doubles the life of the rolling tool. The production operation of grinding the parts of the rolling tool with an abrasive belt and a special machine has been introduced into the Lauristin Tallin Machine Building Plant.

Sultanov, T.A.; Buneev, B.G.; Yurova, T.I.

1982-09-01

405

Phenomena of Foamed Concrete under Rolling of Aircraft Wheels  

Science.gov (United States)

Engineered Material Arresting System (EMAS) is an effective technique to reduce hazards associated with aircraft overrunning runway. In order to ascertain phenomena of the foamed concrete used for EMAS under rolling of aircraft wheel, a specially designed experimental setup was built which employed Boeing 737 aircraft wheels bearing actual vertical loads to roll through the foamed concrete. A number of experiments were conducted upon this setup. It is discovered that the wheel rolls the concrete in a pure rolling manner and crushes the concrete downwards, instead of crushing it forward, as long as the concrete is not higher than the wheel axle. The concrete is compressed into powder in-situ by the wheel and then is brought to bottom of the wheel. The powder under the wheel is loose and thus is not able to sustain wheel braking. It is also found that after being rolled by the wheel the concrete exhibits either of two states, i.e. either 'crushed through' whole thickness of the concrete or 'crushed halfway', depending on combination of strength of the concrete, thickness of the concrete, vertical load the wheel carries, tire dimension and tire pressure. A new EMAS design concept is developed that if an EMAS design results in the 'crushed through' state for the main gears while the 'crushed halfway' state for the nose gear, the arresting bed would be optimal to accommodate the large difference in strength between the nose gear and the main gear of an aircraft.

Jiang, Chun-shui; Yao, Hong-yu; Xiao, Xian-bo; Kong, Xiang-jun; Shi, Ya-jie

2014-04-01

406

Rolling Motions During Solar Prominence Eruptions in Asymmetric Magnetic Environments  

Science.gov (United States)

Panasenco et al. [1] report observations of several CMEs that display a rolling motion about the axis of the erupting prominence. Murphy et al. [2] present simulations of line-tied asymmetric magnetic reconnection that make a falsifiable prediction regarding the handedness of rolling motions of flux ropes during solar eruptions. We will present initial results of our work to investigate this prediction. To determine the strength and any asymmetric properties of the magnetic field in the regions of interest in the photosphere, we use magnetograms from HMI. We use AIA observations to determine if there is any rolling motion and, if so, what handedness the rolling motions have. We then compare the photospheric magnetic information with the handedness information to determine if there is any relationship between the two. Finally, we will discuss prospects for diagnosing rolling motions of erupting prominence using off-limb IRIS observations.[1] O. Panasenco, S. Martin, A. D. Joshi, & N. Srivastava, J. Atmos. Sol.-Terr. Phys., 73, 1129 (2011)[2] N. A. Murphy, M. P. Miralles, C. L. Pope, J. C. Raymond, H. D. Winter, K. K. Reeves, D. B. Seaton, A. A. van Ballegooijen, & J. Lin, ApJ, 751, 56 (2012)

McKillop, Sean; Miralles, Mari Paz; Murphy, Nicholas Arnold; McCauley, Patrick

2014-06-01

407

On the sound radiation of a rolling tyre  

Science.gov (United States)

The sound radiation from rolling tyres is still not very well understood. Although details such as horn effect or directivity during rolling have been investigated, it is not clear which vibrational modes of the tyre structure are responsible for the radiated sound power. In this work an advanced tyre model based on Wave Guide Finite Elements is used in connection with a contact model validated in previous work. With these tools the tyre vibrations during rolling on an ISO surface are simulated. Starting from the calculated contact forces in time the amplitudes of the modes excited during rolling are determined as function of frequency. A boundary element model also validated in previous work is applied to predict the sound pressure level on a reference surface around a tyre placed on rigid ground as function of the modal composition of the tyre vibrations. Taking into account different modes when calculating the vibrational field as input into the boundary element calculations, it is possible to identify individual modes or groups of modes of special relevance for the radiated sound power. The results show that mainly low-order modes with relative low amplitudes but high radiation efficiency in the frequency range around 1 kHz are responsible for the radiated sound power at these frequencies, while those modes which are most strongly excited in that frequency range during rolling are irrelevant for the radiated sound power. This fact is very essential when focusing on the design of quieter tyres.

Kropp, Wolfgang; Sabiniarz, Patrick; Brick, Haike; Beckenbauer, Thomas

2012-04-01

408

Development of a Rolling Process Design Tool for Use in Improving Hot Roll Slab Recovery  

Energy Technology Data Exchange (ETDEWEB)

In this quarter, our primary effort has been focused on model verification, emphasizing on consistency in result for parallel and serial simulation runs, Progress has been made in refining the parallel thermal algorithms and in diminishing discretization effects in the contact region between the rollers and slab. We have received the metrology data of the ingot profile at the end of the fifth pass from Alcoa. Detailed comparisons between the data and the initial simulation result are being performed. Forthcoming from Alcoa are modifications to the fracture model based on additional experiments at lower strain rates. The original fracture model, was implemented in the finite element code, but damage in the rolling simulation was not correct due to the modeling errors at lower strain rates and high stress triaxiality. Validation simulations for the fracture model will continue when the experimentally-based adjustments to the parameter values become available.

Couch, R; Wang, P

2003-05-06

409

Roll-to-roll coated PBI membranes for high temperature PEM fuel cells  

DEFF Research Database (Denmark)

We employed roll-to-roll coating in the preparation of 40 μm thick poly[2,2â?²(m-phenylene)-5,5â?²bibenzimidazole] (PBI) films for fuel cells using both knife-coating (KC) and slot-die (SD) coating. The films were coated directly from a 9% (w/w) solution of PBI in dimethylacetamide onto a sacrificial low cost paper or plastic based carrier substrate and dried using a hot air oven with a length of 1 m at 140 °C. A web width of 305 mm, a working width of 250 mm and a web speed of 0.2 m minâ??1 were explored to ensure efficient drying of the thick wet film. A large air flow was found to efficiently avoid skinning. Films were prepared by a single coating step and by two subsequent coating steps in order to explore whether two coating steps gave films with fewer defects. A significant development towards upscaling the PEM fuel cell technology was that the PBI membrane was coated onto a sacrificial carrier substrate allowing for easy recoating on top of the firstly prepared film. It was thus possible to prepare free-standing films by a simple coating procedure followed by delamination from the carrier substrate post-film formation and drying. We finally carried out systematic membrane characterization with respect to solubility, phosphoric acid doping and fuel cell performance. Our results showed that the PBI membranes prepared in this work have identical properties compared to traditionally cast membranes while enabling an increase of a factor of 100 in manufacturing speed.

Steenberg, Thomas; Hjuler, Hans Aage

2012-01-01

410

Laser processing of organic photovoltaic cells with a roll-to-roll manufacturing process  

Science.gov (United States)

Flexible large area organic photovoltaic (OPV) is currently one of the fastest developing areas of organic electronics. New light absorbing polymer blends combined with new transparent conductive materials provide higher power conversion efficiencies while new and improved production methods are developed to achieve higher throughput at reduced cost. A typical OPV is formed by TCO layers as the transparent front contact and polymers as active layer as well as interface layer between active layer and front contact. The several materials have to be patterned in order to allow for a row connection of the solar cell. 3D-Micromac used ultra-short pulsed lasers to evaluate the applicability of various wavelengths for the selective ablation of the indium tin oxide (ITO) layer and the selective ablation of the bulk hetero junction (BHJ) consisting of poly(3-hexylthiophene):phenyl-C61-butyric acid methyl ester (P3HT:PCBM) on top of a Poly(3,4-ethylenedioxythiophene) poly(styrenesulfonate) (PEDOT:PSS) without damaging the ITO. These lasers in combination with high performance galvanometer scanning systems achieve superior scribing quality without damaging the substrate. With scribing speeds of 10 m/s and up it is possible to integrate this technology into a roll-to-roll manufacturing tool. The functionality of an OPV usually also requires an annealing step, especially when using a BHJ for the active layer consisting of P3HT:PCBM, to optimize the layers structure and therewith the efficiency of the solar cell (typically by thermal treatment, e.g. oven). The process of laser annealing was investigated using a short-pulsed laser with a wavelength close to the absorption maximum of the BHJ.

Petsch, Tino; Haenel, Jens; Clair, Maurice; Keiper, Bernd; Scholz, Christian

2011-02-01

411

Predictive model for the cold rolling process through sensitivity factors via neural networks  

Directory of Open Access Journals (Sweden)

Full Text Available The mathematical modeling of the rolling process involves several parameters that may lead to non-linear equations of difficult analytical solution. Such is the case of Alexander's model (Alexander 1972, considered one of the most complete in the rolling theory. This model requires excessive computational time, which prevents its application in on-line control and supervision systems. In this paper, the representation of the cold rolling process through Neural Networks trained with data obtained by Alexander's model is presented. This representation is based in sensitivity factors obtained by differentiating a neural network previously trained. The representation allows to obtain equations of the process for different operation points with low computational time. On the other hand, the representation based in sensitivity factors has predictive characteristics that can be used in predictive control techniques. Through predictive model, it is possible to eliminate the time delay in the feedback loop introduced by measurements of the outgoing thickness, normally with X-ray sensors. The predictive model can work as a virtual sensor implemented via software. An example of the application to a single stand rolling mill is presented.

Luis E. Zárate

2006-03-01

412

Anti-friction properties of ester additives during hot rolling of aluminum{copyright}  

Energy Technology Data Exchange (ETDEWEB)

Heavy esters of polyhydric alcohols, such as glycerol and synthetic polyols, are commonly used as additives in aluminum hot rolling lubricants. The presence of several hydroxyl groups allows a varying degree of esterification leading to the formation of full and partial esters. These esters are rarely separated from the main additive, and thus may be present in the finished rolling lubricant, affecting its anti-friction properties. The objective of this work was to examine the anti-friction properties of these potential ester contaminants during rolling on a laboratory hot rolling mill. Two lubricant application methods were examined; as emulsion and direct (neat oil) application. The anti-friction properties of additives were found to depend on their chemical structure and the lubricant applications method. In emulsified oils, partial esters of glycerol were found to greatly reduce friction in comparison to triglycerides, while the partial esters of synthetic polyols exhibited only a weak anti-friction effect. There was no frictional advantage observed which could be associated with using the partial esters in direct application mode. Moreover, under these conditions, the anti-friction properties of the completely esterified synthetic polyols were significantly lower than those of triglycerides, while in emulsions they were comparable. 11 refs., 7 figs., 3 tabs.

Januszkiewicz, K.R.; Bekmesian, G.; Heenan, D.F. [Alcan International Limited, Ontario (Canada)] [and others

1995-08-01

413

Predictive model for the cold rolling process through sensitivity factors via neural networks  

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: English Abstract in english The mathematical modeling of the rolling process involves several parameters that may lead to non-linear equations of difficult analytical solution. Such is the case of Alexander's model (Alexander 1972), considered one of the most complete in the rolling theory. This model requires excessive comput [...] ational time, which prevents its application in on-line control and supervision systems. In this paper, the representation of the cold rolling process through Neural Networks trained with data obtained by Alexander's model is presented. This representation is based in sensitivity factors obtained by differentiating a neural network previously trained. The representation allows to obtain equations of the process for different operation points with low computational time. On the other hand, the representation based in sensitivity factors has predictive characteristics that can be used in predictive control techniques. Through predictive model, it is possible to eliminate the time delay in the feedback loop introduced by measurements of the outgoing thickness, normally with X-ray sensors. The predictive model can work as a virtual sensor implemented via software. An example of the application to a single stand rolling mill is presented.

Luis E., Zárate.

414

Research for rolling effects on flow pattern of gas-water flow in horizontal tubes  

International Nuclear Information System (INIS)

The flow pattern transition of two-phase flow is caused by the inertial force resulted from rolling and incline of horizontal tubes under rolling state. an experimental study on the flow patterns of gas-water flow was carried out in horizontal tubes under rolling state, which rolling period is 15 second and rolling angle is 10 degrees, and a pattern flow picture is shown. It was found that there are two flow patterns in one rolling period under some gas flux and water flux. (authors)

2007-04-01

415

Parametric roll due to hull instantaneous volumetric changes and speed variations  

DEFF Research Database (Denmark)

Parametric roll of a containership in head sea condition has been studied in the paper. A time domain routine for GZ righting arm calculation based on exact underwater hull geometry has been implemented into a two-degree-of-freedom procedure for roll response calculation. The speed variation due to e.g. added resistance has been accounted for in the model by the surge velocity. The ship roll motion due to a regular wave critical for parametric roll occurrence has been simulated, as well as the ship roll response in a severe stochastic sea. The present method has been compared with other existing methods for parametric roll prediction.

Vidic-Perunovic, Jelena; Jensen, Jørgen Juncher

2009-01-01

416

Transport properties of cold rolled Ag sheathed Bi(2223) tapes  

International Nuclear Information System (INIS)

For future applications, the magnetic field dependence of j_c is an important quantity. At 77 K the critical current is strongly reduced in the presence of a magnetic field: published values of the ratio j_c(77K,0T)/j_c(77K,1T) typically lie between 3 and 12, the highest ratio being observed for the rolled tapes. Recently we have shown that both hot and cold rolling techniques in addition to the optimization of the total heat treatment time of tapes reduced the ratio j_c(77K,0T)/j_c(77K,1T) for long tapes to a value of about 5, i.e. a value normally observed for pressed tapes. Recent results on cold rolled tapes with improved j_c values and their field dependence are presented here, together with the electrical characterization at different temperatures and magnetic fields. (orig.)

1993-01-01

417

Optical scattering from rough-rolled aluminum surfaces.  

Science.gov (United States)

Bidirectional, angular resolved scatterometry was used to evaluate the feasibility of using rolled aluminum as reflectors in solar thermal collectors and solar cells. Two types of rolled aluminum with different surface roughnesses were investigated. The results show that the smoother of the two samples [rms height, (0.20 ? 0.02) mum] can be used as a nonimaging, concentrating reflector with moderate reflection losses compared with those of optically smooth aluminum reflectors. The sample with the rougher surface [rms height, (0.6 ? 0.1) mum] is not suitable as a concentrating element but can be used as planar reflectors. The orientation of the rolling grooves is then of importance for minimizing reflection losses in the system. PMID:18357222

Rönnelid, M; Adsten, M; Lindström, T; Nostell, P; Wäckelgård, E

2001-05-01

418

Contact pressure in rolled tube-tubesheet joints  

International Nuclear Information System (INIS)

The residual contact pressure in a rolled tube-tubesheet joint is calculated for serveral practical tube-tubesheet size and material selections. The analysis follows the elastic-plastic strain history during the tube expansion process. It accounts also for the initial gap size, reversed yielding, and material strain-hardening of both the tube and the tubesheet. The residual contact pressure is expressed as a function of the degree of expansion of the tube. The inside diameter of the tube after rolling (apparent wall reduction) is chosen as the measure of the expansion. Plots of the residual contact pressure versus the apparent wall reduction shows that in all cases the contact pressure attains most of its value within 3-6% of the apparent wall reduction. Further rolling is of no benefit to the residual contact pressure. (orig.)

1991-01-01

419

Measurements of normal and frictional forces in a rolling process  

DEFF Research Database (Denmark)

To improve the quality of frictional data and to validate the simulations in rolling, a load transducer for measuring normal and frictional stresses in the deformation zone has been developed. 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. By analysing the output from the insert, the frictional stress and normal pressure in the contact zone can be determined. The new concept differs from existing pin designs by less disturbance of lubricant film and material flow and limited penetration of material between the transducer and roll. The transducer is tested at laboratory conditions and is expected to be running in industrial conditions in 2004.

Henningsen, Poul; Arentoft, Mogens

2006-01-01

420

Contact pressure in rolled tube-tubesheet joints  

Energy Technology Data Exchange (ETDEWEB)

The residual contact pressure in a rolled tube-tubesheet joint is calculated for serveral practical tube-tubesheet size and material selections. The analysis follows the elastic-plastic strain history during the tube expansion process. It accounts also for the initial gap size, reversed yielding, and material strain-hardening of both the tube and the tubesheet. The residual contact pressure is expressed as a function of the degree of expansion of the tube. The inside diameter of the tube after rolling (apparent wall reduction) is chosen as the measure of the expansion. Plots of the residual contact pressure versus the apparent wall reduction shows that in all cases the contact pressure attains most of its value within 3-6% of the apparent wall reduction. Further rolling is of no benefit to the residual contact pressure. (orig.).

Kalnins, A.; Updike, D.P. (Dept. of Mechanical Engineering and Mechanics, Lehigh Univ., Bethlehem, PA (United States)); Caldwell, S.M